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Sports Science, 2010.

Sports science: What have the sport scientists done for us? Craig Sharp on the interface between knowledge and p Craig Sharp

Journal of sports science and medicine

Sportscience 14, 29-35, 2010 (sportsci.org/2010/wghBMS.htm)erformance

In 1990 Craig Sharp, recently described (in the BASES journal 2002) as ‘arguably the founder of sports science in the UK’, was heading up the British Olympic Medical Centre, which he had co-founded in 1987. In 1992 he was appointed to the first chair of sports science at the University of Limerick and is currently professor of sports science at Brunel University, with honorary posts at Stirling and Exeter Universities and at the International Equine Institute at Limerick. He is planning to retire soon, partly to concentrate on his life-long interest in Scottish, scientific and sports poetry.

When I first entered the world of sports science at the University of Birmingham in 1971, it was the only British university offering a degree in physical education (later sports science) in Britain. Then came Glasgow, Loughborough and Liverpool. Clyde Williams was appointed to Loughborough soon after, and for some years he and I gave lectures to packed audiences all over the country on aspects of sports physiology. The trouble was that we had to give virtually the same lecture each time, as the knowledge base of each audience at the time was quite low. I well remember Clyde saying to me after one such double act: ‘Craig, we really should stop inventing the wheel every month!’

Because I came from another profession (veterinary medicine), in which I had had some experience of racehorses and racing greyhounds, and because I had been a national runner and a professional squash player, I was especially interested in sports physiology, which I took to be the application to sport of what was known at the time about exercise physiology. A lot was known even then, researched by such famous physiologists as Nobel prizewinner AV Hill onwards, in a succession which included Roger Bannister’s 1950s work on oxygen aspects of running.

Practical application of science

Clyde Williams, Ron Maughan in Aberdeen, Bruce Davis in Salford and some others were more fundamental scientists than I was. They sought to create a good base of published research, while I was more interested in the practical application of that science to competitors and coaches.

I had co-founded the Birmingham Human Motor Performance Laboratory in the early 70s, gradually persuading a series of national squads to visit for testing and advice. These included the GB men’s artistic gymnastics squad, the sprint and slalom canoe squads, the England volleyball squad, the GB judo squad, the GB women’s and men’s squash squads and some of the GB rowers. In addition, a number of individual international competitors from track and field athletics, tennis, shooting and archery came regularly, with their coaches, for testing.

However, until the mid-80s, most elite track and road runners went to the superb labs of Bruce Davis, Clyde Williams and John Humphreys (the latter working in Leeds), where the

genuine expertise for running was concentrated. At the same time, Tom Reilly was making a name for himself in a variety of sports at Liverpool John Moores, as were Ed Winter at Bedford and Tudor Hale at Chichester.

Because of my involvement with Olympic squads (I had helped take 90 competitors to altitude train at St Moritz just before the 1972 Olympics and had been on the British Olympic Association’s Medical Committee since 1972), I was invited in 1987 to set up the British Olympic Association’s physiology laboratories at Northwick Park Hospital, whose Clinical Research Centre was one of the great medical research institutes of Europe.

My five years at the British Olympic Medical Centre (BOMC) coincided with an almost exponential growth in sports science teaching in universities throughout the country, and there are now some 150 sports science courses of various kinds in institutions around the UK.

From around 1990, when PP was founded, sport in general, but especially competition sport, came under a variety of influences all pointing the same way

towards an increasing use of sports science, first physiology but later psychology and biomechanics. In addition to the BOMC, other influences included:

  • The National Coaching Foundation, especially under the brilliant guidance of Sue Campbell;
  • The then British Association of National Coaches, under Geoff Gleason and John Atkinson;
  • Great athletics coaches such as John Anderson, Harry Wilson and Peter Coe;
  • Peter Radford and Neil Spurway with their ‘physiology and sports science’ course in Glasgow;
  • John Brewer at Lilleshall.

Gold standards for lab testing

These and other influences, including the BASES gold standards for laboratory testing and interpretation, paved the way for a massive grassroots increase in the application of science to sport. This was paralleled by the growth and development of the British Association of Sport and Exercise Medicine, together with a major increase in diploma and masters courses in sports medicine in Scotland, England and Ireland.

In the old days, the governing bodies of various sports would send just their squads with their coaches to an accredited laboratory for appropriate testing. Now, however, increasing numbers of governing bodies employ their own sports scientists, who accompany the squads and provide even better liaison between the laboratory and the competitor and coach. At the highest elite level, some individual competitors employ their own personal sports scientists, such as the hugely experienced Joe Dunbar and Leo Faulmann.

What effect has this explosion of interest in sports science had on the sporting world itself? In sport in general, and running in particular, from club level upwards the level of knowledge is very much greater than ever before. Training has been put on a genuinely sound basis, as has nutrition and fluid balance before, during and after various events. Injuries can be managed and treated so that athletes stay in their sport for very much longer than, for example, in the Bannister days.

Professor Tim Noakes’ book Lore of Running, in its fourth (paperback) edition last year, is an unsurpassed source of wisdom on the science and medicine of running, which should be read by every runner from the 800m distance upwards. There are also excellent books, financed by the International Olympic Committee, on the major fitness parameters and on a growing number of individual sports.

But what of the effect on performance? By comparison with the mid-80s, British running above 400m, with the astounding exception of Paula Radcliffe, has been not been notably successful. Partly, of course, this is because much of the rest of the world has latched onto very good training and sports science as well. But it is also because grass-roots athletics has withered away to a considerable extent in Britain, with the elite tending to cut themselves off from club events. For it is a sad paradox that an unprecedented explosion in knowledge about how to push the boundaries in sport has been accompanied by a parallel explosion in sedentary leisure pursuits (home computers, video, DVDs etc) that has made young people less and less eager to explore those boundaries.

Where do all the sport and exercise science graduates go? Before the second world war a classics degree was seen as a basic education, which few students ever thought to make their life’s work. Sport science degrees have, to some extent, filled part of that general educational niche. A degree course with a spectrum ranging from statistical analysis and biomechanics through psychology and physiology to sports philosophy and sociology certainly offers an excellent general education, reflected in the very broad range of occupations such graduates enter.

Nevertheless, a substantial proportion of those graduates go on to work in sport or fitness, while growing numbers are absorbed into the various areas of health science. But herein lies a real problem for sport science. University departments are powerfully research driven these days in order to stay afloat financially and attract good staff and students. But the grant money for research into sport is very limited, partly because it tends to fall between stools, being perceived as too medical for the science funding bodies and too scientific for their medical equivalents. Money is available primarily for the application of sporting disciplines to health and medicine. Not for nothing did the original British Association of Sports Science become Sport and Exercise Science and the British Association of Sport and Medicine morph into Sport and Exercise Medicine.

My dream of a National Sports University for the UK

Excellent and relevant research into sport is being carried out — but not nearly as much as one would like. I used to dream of a National Sports University — Loughborough, Birmingham, Borough Road or Stirling on a grand scale, where genuine critical mass would be achieved within the major laboratory-based disciplines of physiology, psychology and biomechanics. But I don’t know whether it will ever be realised.

What have been the main trends in research, and what are the outstanding challenges? In terms of running, physiological research has gradually been shifting towards more detailed treadmill testing for running economy, lactate thresholds and ‘lactate minimum’ levels. A major problem in assessing runners is that about 50% of the energy of each running stride is stored and released as ‘elastic energy‘ in tendons and ligaments, yet we are only able to measure the other 50%, which is delivered by muscle. The development of simple accurate systems for measuring elastic energy would represent a real breakthrough in running science.

Runners’ fluid balance, glucose and salt requirements are reasonably well understood, thanks to Ron Maughan inter alia. Heat acclimatisation strategies are good, and there are some regimens to help athletes resist pollution.

Strategies to combat the effects of jet lag have been well researched by Tom Reilly; the principles of carbohydrate-loading are very well established; there is a growing research on creatine, and the ‘new creatine’ may well turn out to be carnosine, ingested to help the muscle cells buffer lactic acid internally, which is being researched by Roger Harris of Chichester.

From nutrients to supplements

Sports nutrition in general is moving on from study of the major nutrients — carbohydrate, protein and fat — to research into specific chemicals, such as glutamine to assist immune cells, and ‘branched chain amino acids’ to lessen central fatigue. And this is where one begins to enter the confusing realm of supplements, with all their attendant doping hazards for competitors.

Thus, the last 35 years have witnessed an accelerating groundswell of knowledge applied to sport. And in the 14 years of Peak Performance’s life there has been an exponential increase in all aspects of sports knowledge in general and running in particular — of which the very existence of PP is living testimony.

Although I began this piece by listing a number of elements of ‘expert input’ into sport, I have focused mainly on just one of them — physiology. In their varying ways, all the other elements have made progress which is as great, or even greater, and will continue to do so.

But when it comes to factors that enhance performance, knowledge is not necessarily the most important. A major factor in the everincreasing performance in running, for example, is that the more people who run, from all nations of the world (and some parts have hardly begun to compete yet) the greater the chance of throwing up what are known in statistics as ‘outliers’ — those freakishly talented individuals who set world records.

Horses, through a century-old breeding programme, have exposed their species’ outliers and are now being limited by physiology itself. But humans are still a very long way from reaching their physiological limits. We have by no means fully trawled the running genes of our species — let alone set about improving them!

Biomechanics and Medicine in Swimming XI: the 2010 International Symposium in Midsummer Oslo

Will G Hopkins, Tom J Vandenbogaerde

Institute of Sport and Recreation Research NZ, AUT University, Auckland 0627, New Zealand; Email. Reviewer: Kari Keskinen, Finnish Society of Sport Sciences, Olympic Stadium, FI — 00250 Helsinki, Finland.

Abstract:

This quadrennial conference was hosted in 2010 by the Norwegian Sport University, NIH. Amongst the best performance-related presentations were a case study of a change in butterfly kicking style and large-scale longitudinal studies of talent identification and overtraining in swimmers. Novel Technologies and Analyses: pressure across the hand, active drag, computational fluid dynamics, markerless video analysis, beat the bubbles, frontal crosssectional area, data-loggers/accelerometers, controlled trials with competitions, free simulation software. Starts and Turns: gliding, starting blocks, step starts, entry styles, underwater turn, start-time feedback, relay changeover, other starts and turns. Strokes and Kicking: limb coordination, freestyle/front crawl, butterfly. Training: reducing volume, overtraining, imagery, altitude, taper, strength. Water Polo: tests, offensive strategies. Miscellaneous: talent identification, trends and performance trajectories, skill acquisition, tests, lactate, swim suits, mushrooms. KEYWORDS: elite athletes, psychology, skill, technology, tests, training.

The 2010 quadrennial BMS conference in Oslo was memorable for the midnight twilight, the mainly wonderful summer weather, the nearby Nordic forests and lakes, the mayoral reception at the town hall, where one wall was a vast painting of Norwegians in an idyllic natural setting, and the amazing Vigeland Sculpture Park, featuring many more natural Norwegians. Is the Scandinavian attitude to nudity an evolutionary adaptation to the need for vitamin D? Also memorable and much appreciated was the thorough and thoughtful planning by our hosts at the Norwegian Sport University (Norges idrettshøgskolen, NIH), who provided an opening fanfare by a brass quartet of student musicians, a closing flute solo, free wi-fi, classy conference backpacks, and highest-quality espresso coffee throughout the conference.

And there were some great presentations! Here we report only on those with practical application to competitive swimming performance or to research thereon. If your interest is the clinical, safety, adapted, or educational aspects of swimming, peruse the book of abstracts (see below) to find the many relevant presentations.

Prizes for the best oral, poster and student presentation (the Archimedes Award) went to topics related to health and mechanisms. We had to wait for nearly the last poster on the last day for our choice of the best performancerelated presentation: a case study by the coach of a top butterfly swimmer, who persevered with a change in kicking style for two years before his swimmer «got it» (to use his words) and went on to a personal best at age 30. See below. Runners-up were massive longitudinal studies of talent identification and overtraining.

Although this conference is focused on one sport, it is organized under the auspices of the World Commission of Science and Sports. WCSS is dedicated to bringing science to sport and to bridging gap between scientists and practitioners. There’s a lot to be said for such specialty conferences, and this one was also just the right size: ~300 delegates (most of whom gave at least one presentation), nine unopposed keynote presentations, 125 oral presentations in three or four streams that didn’t clash too badly, and 125 poster presentations. A real plus was having all the posters displayed throughout the conference, so there were many unopposed hours to view them. Each poster was also presented in four parallel chaired sessions, which was only partially successful, owing to the overlap of content, the crush of people, and the background noise: you had to fly backwards and forwards and make a special effort to push to the front to hear the presenter. In future we need email addresses in the abstracts so we can arrange to interact with presenters during or after the conference.

To mark the 40 years since the inception of BMS, João Paulo Vilas-Boas included in his opening address a quantitative review of the contents of the previous and current conferences. The main topics have always been biomechanics, physiology and «evaluation», with medicine and other disciplines playing roles similar to those at any sport-science conference. So whether or not you are a biomechanist or a medic, if you are interested in swimming research, come to the 2014 conference. The venue was announced at the closing ceremony: the Australian Institute of Sport, Canberra, and it will be sometime near Easter.

Videos of the keynote presentations are now available at the Coaches Info website. The conference abstracts can be downloaded as a PDF from the conference website. A welcome difference from the ACSM meeting, along with the incomparable coffee, is the availability of abstracts for all presentations. Even more welcome, and for the first time, the volume of full papers will also be available free as a 10-MB PDF, the aim being to get more recognition and citations of the published work. For access to a particular paper before the password-protection is removed from the PDF, contact us. To make the most of the abstracts, we suggest you get a small group together (no more than five) with an interest in a specific stroke or topic, set up the PDF of the abstracts on a big monitor, then use the Search window (not the Find form) to link to each abstract containing an appropriate keyword. It’s great fun, and you will learn things from each other, as well as from the abstracts.

In what follows, use the code number shown in brackets (…) to search the abstracts PDF for the given abstract. Text after the number represents the first few words of the title that will take you uniquely to the paper when you search for it in the full volume. Abstract only implies either that the authors did not submit a full paper or that the submitted paper was rejected in the peer-review process.

In evaluating effects on performance, it’s important to keep in mind the changes that will improve or impair the medal prospects of a top athlete. The smallest important such change is 0.3 of the amount of variation (expressed as a standard deviation) that a typical top athlete shows from competition to competition (Hopkins et al., 1999; Hopkins et al., 2009). An elite swimmer’s time varies in this way by only 0.8% (Pyne et al., 2004), so the smallest important change in swim time is 0.3 of 0.8%, or about 0.25%. Use this value even for research on subelite competitive swimmers, in the hope that the findings will apply to elites. For research on youth swimmers aimed at team selection or talent identification, the smallest effect may be better defined via standardization: 0.20 of the between-swimmer standard deviation. See Magnitude Matters for more.

Novel Technologies and Analyses

An Italian group think they have developed the best technology yet for measuring thrust developed by the hand via pressure differences across the hand (O-002, abstract only). Another group has developed algorithms to analyze the data from 12 pressure sensors on the hand (O-005, Prediction of Propulsive…).

You can detect left-right asymmetry and wide swings in instantaneous stroke force by measuring «active drag»: the tension in a line used to drag a swimmer through the water at slightly above maximum swimming speed while the swimmer swims all out (O-004, Measuring Active Drag…). This technique is not particularly new, and you can get the same information from an instrumented tether: synchronize it with video analysis and you can see what’s going wrong. There was a good trade display of the latest version, the Torrent ERack, which for US$10,000 incorporates resisted training, assisted training, and synchronized video. The much simpler passive tether costs US$3000.

Bruce Mason gave only an average account of the biomechanics of active drag (O-006, A Method to Estimate Active…), but he redeemed himself completely in a keynote address about the biomechanical services provided to swimmers and their coaches at the Australian Institute of Sport in Canberra (KL-004, Biomechanical Services…). He presented a series of case studies of starts, turns, and swim strokes, where the high-tech equipment in the new pool at the AIS has been used to improve performance.

Most promising of the recent wizardry is the use of computational fluid dynamics (CFD) to combine the swimmer’s anthropometry (from laser scan) with the swimmer’s current swimming style (from video analysis) to develop a computerized mathematical model of the swimmer actively swimming through water, complete with simulations of the vortices and waves that limit speed. The model can then be used to predict ways to improve the swimmer’s technique, and you try out the most promising in the pool. The method has been around for some years now, and although we got the impression that one more level of model development and computer power is needed to fully realize the potential of this approach, it was rumored that the Russians might already be there. Swimming at the next Olympics may be partly a contest between nations with the most money to spend on computers and computer programmers.

A CFD analysis of finger positions of an elite male swimmer reached the following conclusion (O-076, abstract only): «For hand positions in which lift force plays an important role (e.g., insweep phases), abduction of the thumb may be better, whereas at higher angles of attack… the adduction of the thumb may be preferable... Fingers [should be] slightly spread… to create more propulsive force.»

Development of markerless automated video analysis appears to be close to practical implementation (O-050, abstract only), the main breakthrough apparently being a statistical approach to dealing with the obscuring action of bubbles. Another group beat the bubbles by using a regression technique to identify limb-segment midlines in an analysis of the dive of 16 male elite swimmers (P-014, abstract only). Faster starters used a dolphin kick and performed deeper dives.

It’s now possible to get a reasonable estimate of frontal cross-sectional area (responsible for drag) from an analysis of movements in the sagittal plane recorded from a single side-on camera (O-053, abstract only). We’re not sure how this approach will «provide new practical insights into swimming analysis protocols».

Apparently successful merging of video with the data stream from a 3-D accelerometer-gyroscope data-logger was made possible by addition of a depth gauge with a resolution of 10 cm to the device (O-055, Whole Body Observation…). «Wavelet analysis» also helped, but it was difficult to understand the presenter on this point. Another author claimed that «the feasibility to use inertial sensors [accelerometer-gyroscopes] to characterize turning, gliding and stroke resumption in swimming was verified» in eight elites doing various swim movements (O-123, Analysis of Swim Turning…). We are skeptical about the current practicality and bulk of these devices.

You can get a swimmer’s position down to an accuracy of one frame of a 25-Hz video if you use 2-D direct linear transformation (DLT) analysis of footage from three cameras (O-056, The Validity and Reliability of a Procedure…).

If your team competes often in a season, and there are plenty of other teams in the competitions, and your coach wants to try some new strategy with the whole team, and the coach hasn’t done anything else substantially different so far in the season, you can use competition results to estimate the effect of the strategy (O-073, abstract only). The uncertainty of the estimate is typically about one third of what you get from the usual controlled trials, and the outcome is as valid as it is possible to get: the effect on competitive performance. It’s best done with mixed modeling.

It was demonstrated at the last BMS meeting, but the authors have updated their free swimming simulation software (Swumsuit), and it looks very cool indeed, at least for teaching (O-126, P-029, Advanced Biomechanical Simulations…) and possibly for research (P-030, abstract only). Downloads and more at the SWUM website.

Starts and Turns

Kinetic analysis of gliding combined with planimetry to determine crosssectional area in six national-level males led the authors to recommend more emphasis on control of body position during the glides to reduce drag (O-078, Hydrodynamic Characterization…).

A new FINA-sanctioned starting block with side grips and a steeper angle (9° rather than 5°) appears to produce starts that would represent a substantial small effect for 50and 100-m events in seven male swimmers (P-004, abstract only) and in 14 elite swimmers (O-083, A Biomechanical Comparison of Elite…). The authors of the latter study concluded that «coaches and athletes should spend time adapting to the new block and the new starting technique».

Step starts were statistically significantly faster than no-step starts in repeated trials of relay changeovers (O-084, Comparison among Three…), but this is one of those occasions where statistical significance of a trivial effect practically guarantees the effect isn’t worth worrying about. The swimmers also made more «missed trials» (bad changeovers?) with step starts.

A randomized controlled trial of 5+5 elite swimmers compared outcomes of instruction on pike vs flat entry (O-086, abstract only). Both groups changed their entry style significantly, but whether the changes would have substantial effects on swim time was unclear.

Does a new «apnea» underwater turn (O-119, An Analysis of an Underwater…) offer any advantages for the butterfly and breaststroke? The mean gain in time for the 10 swimmers was 0.07 s on average, which is not worthwhile, but apparently the swimmers had practiced the turn for only a few sessions (not stated in the abstract or full paper). So it might be worthwhile with enough practice, but only for 50or 100-m events: the presenter mentioned that the reduction in breathing would probably impair performance in races with more than one turn.

A controlled trial of the effect of giving feedback about start times produced a statistically significant improvement in start time in the experimental group (O-121, abstract only), but it was done with regional-level swimmers and physed students, and in any case the gains would probably translate into a trivial effect in 50-m swim time. Inferring significance apparently via a comparison of P values in the two groups is also forbidden, although the presenting author said that this was a mistake in the abstract.

In the first of two controlled trials aimed at improving relay changeovers (O-122, abstract only), both groups of 13 junior elites received video feedback for the 4 d of training, but one group was given additional feedback on horizontal take-off force while the other received feedback on changeover time. The group receiving force feedback made bigger reductions in changeover time that would probably translate into medals (not enough data presented to be sure), and they made less false starts. In the other trial, eight elites practiced the traditional arm-swing start while another eight learned a single-step start. Both groups improved by a similar amount, but it’s unclear from the ambiguous abstract whether the step start was better.

There was no immediate application to race times, but the following analyses may be of interest nevertheless: backstroke start (P-009, Biomechanical Characterization…); flat, pike or Volkov starts (O-085, Influence of Swimming Start…); and gliding (P-036, Evaluation of the Gliding…) .

Several correlational studies of starts or turns and performance time suffered from woefully inadequate sample sizes. Unless the relationships are very strong and therefore obvious anyway (for example, when there are novice and expert swimmers in the sample), you need hundreds of subjects to do the job properly. The only way correlation can work with samples of 10-20 is when the correlated variables are change scores derived from repeated measurements, in which the subjects spontaneously vary their technique substantially and there are substantial differences in the change in performance–see, for example, the paper on effects of tapering (P-

072) reported in more detail below. It’s even better when you make multiple observations on each subject, derive a slope representing the relationship between the movement and performance for each subject, then process the slopes with a simple t statistic. (See within-subject modeling for more.) Anyway, here’s a quick list of the studies: kinematic analysis of grab start in 12 national level (and this involved stepwise regression, which is right out of the question with this sample size) (P-020, Kinematics Analysis of Undulatory…); kinematic analysis of water-entry skill in 14 college elites (P-024, abstract only); and kinematic and kinetic analysis of tumble turns in eight elite females (P-033, Biomechanical Factors Influencing…).

Strokes and Kicking

In a keynote and original-research presentation on limb coordination (KL002, Inter-Limb Coordination in Swimming), Ludovic Seifert mentioned complex systems, dynamical system theory, self-organization, and various constraints, although you don’t have to understand these concepts to appreciate his main finding: the best swimmers achieve overlap of the propulsion phase of each arm at race pace, presumably by shortening the recovery phase of each stroke. Is there an application to performance enhancement here? Seifert also presented several original-research studies on coordination (O-044, Arm Coordination, Active Drag…; P-037, Modelling Arm Coordination…).

A string of light-emitting diodes down each arm facilitated automatic digitizing (P-127, Preliminary Results of…). Combined with high-speed video of four elite freestylers, the technique revealed that forward thrust (as determined by hip forward velocity) is maximum midway through the stroke rather than towards the end, as traditionally taught, and that these swimmers adopted an elbow angle of ~130° rather than the recommended 90°. The authors are getting a bigger sample size.

The findings were inconclusive with respect to race times, but you may have an interest in video analyses of front-crawl (P-005, P-035, abstracts only), and the freestyle in the previous paragraph.

Analysis of pressure difference across the hand combined with video of 23 varsity-level butterfly swimmers revealed patterns of hand-force development that led to the following conclusions: coaches can adjust entry angle to eliminate time wasted when the hands are above the shoulders, and coaches can also encourage swimmers to begin elbow flexion as soon as the entry is complete (O111, Quantitative Data Supplements…).

The most inspirational presentation for us was the case study presented by the coach of the 100-m butterfly Asian record holder, who took two years to change his kicking style, then went on to set a personal best as a 30-year old (P077, Effects of Reduced Knee-bend…). The swimmer was taught to keep his legs straight in the upbeat and to delay bending the knees until the downbeat was initiated. The presentation of the longitudinal monitoring was almost exemplary, lacking only an inferential statistic for the uncertainty in the change in performance (but the effect was so clear that it didn’t matter).

Training

Continuing the long tradition initiated by Dave Costill, a group from Denmark reported on the effect of halving training volume and increasing training intensity for 12 weeks in a randomized controlled trial of 16+15 elite swimmers (20 male, 11 female) (O-026, P-078, abstracts only). VO2max dropped significantly by 3.8% in the experimental group compared with control. It was also apparent in the presenter’s slide that performance in an all-out 200-m test also declined by about 1.5%, but it was non-significant and it was presented as no change. On the other hand, 100-m sprint performance apparently improved, but the comparison of the changes in the two groups is not in the abstract. Amazingly, the coach allowed this 12-week study to straddle the Danish national championships, but the group had not investigated the effect of the first 6 wk of the program on change in competitive performance since the previous competition. Hopefully they will, and report it using chances of benefit and harm with respect to a smallest important change of 0.25%.

In a sometimes overwhelming keynote lecture, Pierre-Nicolas Lemyre told us all about one of the biggest and best studies yet of overtraining/burnout (KL-006, The Psycho-Physiology of Overtraining…), involving psychometrics, hormones, and double maximal stress testing of 53 elite swimmers at the easy beginning (September), very hard middle (November), and peaking end (March) of a six-month season. A measure of lack of motivation at the beginning of the season was the best predictor of level of burnout in the middle (r=0.52) and at the end (r=0.55). Change in cortisol in the stress test and several other measures were also substantial predictors of burnout, altogether giving a correlation of

0.82 in a multiple linear regression. Predictors of performance change from the previous season to the end of the monitored season were not presented in the abstract or the paper, alas, but presumably they would have been similar to the predictors of burnout. Now we need studies of interventions based on the predictors and aimed at reducing risk of burnout and enhancing performance. Let’s hope you can do both in the same athlete.

There was apparently no significant effect of 3 wk of supplemental imagery training on performance in a controlled trial of 8+8 13-y old kids, but not even the full paper showed any data (P-107, Imagery Training in Young…).

Ferran Rodriguez presented a keynote on altitude training for swimmers (KL-008, Training at Real…), in which he gave credit to a recent meta-analysis of performance effects of the various kinds of hypoxic exposure (Bonetti and Hopkins, 2009), unfortunately without drawing on its findings. The forthcoming multicenter altitude study he promoted here and in an earlier presentation (O052, abstract only) would be a good opportunity to try out the competition-based new research design (O-073, abstract only, see above).

The reduction in training load during a taper before a national competition in 12 age-group swimmers correlated clearly and substantially (r=0.63) with change in performance in the competition from the previous «starting list time» (P-072, Changes of Competitive Performance…). When asked, the presenter thought the correlation was due more to higher training at the start of the taper than lower training at the end; that is, those who reached a higher training load before the taper had bigger gains in performance.

Four weeks of strength training improved the start times of five male and two female national-level swimmers by an average of 0.07 s (P-075, abstract only), or about 0.3% in a 50-m race. Although this change is the smallest worth having, it would be important to ensure the benefit transfers to actual overall swim time.

Water Polo

Means and standard deviations were reported for a new test battery (P-094, abstract only), but there were no statistics for validity (e.g., correlation with ability of players) or reliability (e.g., test-retest correlation). The same group reported a correlational study of muscle strength and throwing speed with 15 players (O-038, abstract only). See our earlier comments about inadequate sample size.

Looking for patterns of play in games using sophisticated modeling may be the way of the future. Here a group used Markov chains to analyze offensive play in 11 games between the same two teams at a world league final (O-041, A Markov Chain Model). Their conclusion: fast breaks and intense activities of the back players are important.

Miscellaneous

In a spectacular study of talent identification (O-071, Talent Prognosis…), 21 measures of fitness and anthropometry were taken on over 700 children of age 14 ± 4 y (mean ± SD) from two elite sport schools. Swimming competition data were collected ~7 y later on the 130 male and 113 female survivors (age 21 ± 3 and 20 ± 3 y). They were divided into three talent groups (why not use percent of world record as the outcome?), then linear and neural-net models were developed to predict the talent grouping from the original test scores. The neural net worked much better than the linear model, correctly predicting the talent group for 88% of the girls and 68% of the boys compared with only 69% and 50% respectively. The linear model does manage to identify the tests that matter most (extrinsic motivation–oh dear!–and a composite factor called swimming coordination), whereas a neural net is a black box that doesn’t tell you what matters without extensive probing. Now what? Use the neural-net model to help filter future intakes?

Mixed modeling is the secret for analyzing age and calendar year trends in overall competitive performance times and for predicting performance of individual swimmers from their «quadratic trajectories» (O-074, abstract only). Is this the way to identify your country’s strong and weak events and your promising talented individuals?

Stephen Langendorfer gave an inspirational keynote on skill acquisition at different stages of the lifespan (KL-007, Applying a Developmental Perspective…). But as an audience member summarized it in question time, he hijacked all the good techniques in teaching under his banner of the developmental view, and left all the bad things under the error-correction view. Perhaps he should have given some credence to this prevailing view, given that we seem to have evolved to acquire behavior and culture in this efficient manner.

Our comments about sample size in correlational studies in the section on Starts and Turns applies to a study of field tests in 12 swimmers (P-110, abstract only) and of fitness tests in 25 male adolescents (P-079, abstract only). With larger sample sizes outcomes are clearer, although hardly surprising in the study of fitness tests of 72 young swimmers (P-121, Predictors of Performance…).

Some of the papers relating to lactate measurement sported big names, but we consider these to be of marginal utility. Those interested should search the abstract PDF for lactate. We have adopted the same approach to the many studies of swimsuits.

By our calculations from the full paper, Olympic swim times in the 2008 games were faster than predicted from the trend over previous Olympics by a large 1.7 ± 0.7 % (mean ± SD) (P-088, Identification of a Bias…). Swimsuits were surely the main reason?

There was an intriguing abstract about beneficial effects of a mushroom extract on «infection, allergy and inflammation that… may improve health and training-related inflammation in elite swimmers and other athletes» (O-021, abstract only). Unfortunately the author did not turn up to present the study and to answer questions about the potentially harmful effects of anti-inflammatories and antioxidants on training adaptations. See this year’s ACSM report for more on this topic.

Acknowledgements: funding to attend the conference was provided in part for WGH by the Norges idrettshøgskole and by Sport and Recreation NZ for WGH and TJV. Salary support was provided by AUT University for WGH and by Swimming NZ for TJV.

Reviewer’s Comment

This is an excellent analysis of performance-related papers presented in BMS

XI. I have noticed a trend towards more controlled trials at this conference, but sample sizes are still generally too small to study the small effects that make a difference to medal-winning. Placebo effects, both positive and negative, are also a problem in studies where swimmers cannot be blinded to the treatments. – Kari Keskinen

References

Bonetti DL, Hopkins WG (2009). Sea-level exercise performance following adaptation to hypoxia: a meta-analysis. Sports Medicine 39, 107-127

Hopkins WG, Hawley JA, Burke LM (1999). Design and analysis of research on sport performance enhancement. Medicine and Science in Sports and Exercise 31, 472-485

Hopkins WG, Marshall SW, Batterham AM, Hanin J (2009). Progressive statistics for studies in sports medicine and exercise science. Medicine and Science in Sports and Exercise 41, 3-12. Link to PDF.

Pyne D, Trewin C, Hopkins W (2004). Progression and variability of competitive performance of Olympic swimmers. Journal of Sports Sciences 22, 613-620

Published July 2010

Journal of sports science and medicine

Sportscience (2009) 8, 89 — 96 (sportsci.org/2009/wghBMS.htm

SHORT AND LONGER-TERM EFFECTS OF CREATINE SUPPLEMENTATION ON EXERCISE INDUCED MUSCLE DAMAGE

John Rosene, Tracey Matthews, Christine Ryan, Keith Belmore, Alisa Bergsten, Jill Blaisdell1, James Gaylord, Rebecca Love, Michael Marrone, Kristine Ward and Eric Wilson

Health and Human Performance Department, Plymouth State University, Plymouth, NH, USA

Exercise Science and Sports Studies Department, Springfield College, Springfield, MA, USA.

Abstract

The purpose of this investigation was to determine if creatine supplementation assisted with reducing the amount of exercise induced muscle damage and if creatine supplementation aided in recovery from exercise induced muscle damage. Two groups of subjects (group 1 = creatine; group 2 = placebo) participated in an eccentric exercise protocol following 7 and 30 days of creatine or placebo supplementation (20 g.d-1 for 7 d followed by 6g.d-1 for 23 d = 30 d). Prior to the supplementation period, measurements were obtained for maximal dynamic strength, maximal isometric force, knee range of motion, muscle soreness, and serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH). Following 7 days of creatine supplementation, on day 8, subjects began consuming 6 g.d-1 of creatine for 23 days. Additionally on days 8 and 31, subjects performed an eccentric exercise protocol using the knee extensors to induce muscle damage. Indirect markers of muscle damage, including maximal isometric force, knee range of motion, muscle soreness, and serum levels of CK and LDH, were collected at 12, 24, and 48 hours following each exercise bout. The results indicated that acute bouts of creatine have no effect on indirect markers of muscle damage for the acute (7 days) bout. However, maximal isometric force was greater for the creatine group versus placebo for the chronic (30 days) bout. This suggests that the ergogenic effect of creatine following 30 days of supplementation may have a positive impact on exercise induced muscle damage.

Key words: Soreness, isometric force, eccentric

Introduction

Creatine supplementation has been widely studied as an ergogenic aid relative to performance in high-intensity activities (Burke et al., 1996; Casey et al., 1996; Greenhaff et al., 1993; Harris et al., 1992; Kreider, et al., 1998; Odland et al., 1997; Terjung, et al., 2000; Volek, et al., 1999; Willoughby and Rosene, 2001). Others have examined clinical aspects of creatine supplementation such as potential adverse effects in muscle injury (Krieder, et al., 1998), thermoregulation (Kern et al., 2001; Rosene et al., 2004; Volek, et al., 2001), and renal complications (Boswell et al., 2003). These studies have led investigators to examine potential clinical benefits of creatine supplementation such as with recovery from exercise induced muscle damage (Rawson et al., 2001

Exercise-induced muscle damage has been shown to result from strenuous, unaccustomed exercise. The damage that occurs is primarily due to eccentric muscle actions and affects the structural composition of muscle leading to impairments in performance. These structural changes in muscle include mechanical factors, alterations in calcium homeostasis due to sarcoplasmic reticulum disruption, and the inflammatory response (Clarkson and Sayers, 1999).

As part of the repair process, protein synthesis is enhanced via several mechanisms including the stress proteins which have been found to be upregulated following a bout of eccentric exercise (Willoughby et al., 2003). Creatine supplementation has also been shown to impact protein synthesis resulting in alterations in skeletal muscle composition. Twelve weeks of creatine supplementation (25g.d-1 for 1 wk; followed by 5g.d-1 for 12 wks) resulted in increased muscle fiber cross sectional area when compared to placebo for type I

(35% vs 11%), type IIa (36% vs 15%), and type IIb fibers (35% vs 6%) (Volek et al., 1999). Additionally, greater increases were found for type I, type IIa, and type IIx MHC mRNA expression for creatine supplemented individuals compared to placebo. For these changes in MHC mRNA expression, subjects were supplemented with 6g.d-1 for 90 days with no loading phase (Willoughby and Rosene, 2001).

Rawson et al., 2001 reported that 5 days of creatine supplementation (20g.d-1)

did not reduce indirect markers of muscle damage or reduce recovery time following eccentric exercise. Increased muscular strain as a result of the eccentric exercise was believed to have caused structural damage within the muscle thereby limiting creatine’s effects on cellular membrane stability. As such, sarcolemmal and sarcoplasmic reticulum damage may have been too extensive for a 5-day supplementation protocol to have any impact (Rawson et al., 2001).

The symptoms of delayed onset muscle soreness which include strength loss, pain, muscle tenderness, stiffness, and swelling, have been reported to occur within 48 hours of damage and last beyond 5 days. Degradation of contractile proteins appears to contribute to decreases in muscular force 5-28 days post eccentric exercise (Ingalls et al., 1998). Therefore, reductions in force output immediately following a bout of eccentric exercise and up to 5 days may be related to the inflammatory response associated with cellular membrane damage (Connelly, Sayers et al., 2003). Any effects of creatine supplementation impacting myofibrillar protein content would not be evident until between the 5 and 28 day time period.

Athletes have also anecdotally reported decreased fatigue, decreased muscle soreness, and decreased recovery time while supplementing with creatine. With evidence to support increased myofibrillar protein synthesis, muscular hypertrophy, and muscular strength with creatine supplementation it is possible that creatine supplementation will have positive effects on indirect markers of exercise-induced muscle damage (Willoughby and Rosene, 2001; Volek, et al., 1999). Based on previous reports of enhanced creatine uptake with exercise and positive effects on skeletal muscle composition, (Burke et al., 1996; Casey, et al., 1996; Greenhaff, et al., 1993; Harris et al., 1993; Kreider, et al., 1998; Odland, et al., 1997; Terjung, et al., 2000; Volek, et al., 1999; Willoughby and Rosene, 2001) longer supplementation protocols may also be helpful in decreasing exercise-induced muscle damage. Therefore the purpose of this investigation was to determine the effects of 7 and 30 days of creatine versus placebo supplementation on indirect markers of muscle damage following a bout of eccentric exercise.

Methods

Subject

Twenty males, were randomly assigned to a creatine (CR) or placebo (P) group (CR = 10; P = 10). For the CR group subjects were 21.6 ± 1.65 yrs, 1.77 ± 0.07 m, 84.0 ± 8.3 kg, and 12.95 ± 4.76% body fat. For the P group subjects were 21.60 ± 0.70 yrs, 1.753 ± 0.06 m, 84.0 ± 13.4 kg, and 11.75 ± 4.72% body fat. The subjects were physically active (consistent physical activity for 6 months prior to beginning the study) and free of creatine supplementation for at least 60 days prior to beginning the study. All subjects were required to read and complete a medical history form to ensure that eligibility criteria were met. All subjects were informed of the purpose and possible risks involved in the investigation and were required to read and sign an informed consent prior to participation. All procedures were approved by the University Institutional Review Board.

Blood sampling

For serum creatine kinase (CK) and lactate dehydrogenase (LDH), blood was drawn from the antecubital vein into a 10 mL collection tube via a Vacutainer apparatus. The blood samples stood for 10 min, were centrifuged to extract the serum and frozen at -20°C for later analysis. Blood samples were obtained prior to each eccentric exercise bout and also at 12, 24, and 48 hours post-exercise. Serum CK and LDH were analyzed via reflectance spectrophotometry with the dry-chemistry technique utilizing the DT60 II Chemistry System (Orthoclinical Diagnostics, Raritan, NJ) at 680 nm (CK) and 340 nm (LDH) following manufacture’s guidelines.

Muscle strength assessment

Maximal dynamic strength (MDS) of the dominant (acute) and nondominant (longer-term) thigh was assessed using a Body Masters (Rayne, LA) seated leg extension machine via a standard one repetition maximum (1-RM) test prior to the eccentric exercise protocol. The concentric 1-RM measure was used to determine the eccentric load of 150% of the concentric 1-RM. A maximum of four sets was used to determine the 1-RM in order to counteract muscle fatigue (Willoughby and Pelsue, 1998; Willoughby and Rosene, 2001).

Maximal isometric force (MIF) was determined using the Biodex System 2 (Shirley, NY) isokinetic dynamometer. Subjects were seated with the leg positioned at approximately 45° of knee flexion. The Biodex was set at 0° per second or in isometric mode and the subject performed 3 maximal isometric contractions with 1 minute rest between trials. The average score was used as the criterion.

Knee range of motion and muscle soreness

Knee range of motion (KROM) was assessed using standard goniometric techniques with the subject in the prone position (Norkin and White, 1995). The evaluator passively moved the involved knee into the flexed position (heel moving towards the buttocks) while the hips were maintained in neutral. The position of the knee at which the subject attempted to lift the hips off the table or indicated maximal knee motion was used as the measurement

Perceived muscle soreness (SOR) was assessed by each subject placing a mark along a 25.4 cm continuum, with 0 indicating no muscle soreness and 25.4 cm indicating very, very sore (Willoughby et al., 2003)

Testing protocol

Two groups of subjects (group 1 = creatine; group 2 = placebo) participated in an eccentric exercise protocol following 7 and 30 days of creatine or placebo supplementation. Prior to the supplementation period, baseline measures were obtained for MDS, MIF, KROM, SOR, and serum levels of CK and LDH.

Following the 7 days of creatine supplementation (20 g.d-1), on day 8 (acute effect), subjects began consuming 6 g.d-1 of creatine for 29 days. Additionally on day 8, subjects performed a knee extension eccentric exercise protocol to induce muscle damage of the knee extensors. The eccentric exercise protocol consisted of a warmup bout of 1 set of 10 repetitions at 50% of the previously determined concentric 1-RM. Subjects then performed 7 sets of 10 repetitions at 150% of the concentric 1-RM using eccentric contractions, with each repetition lasting 2-3 seconds and 15 seconds rest between each repetition. A 3 min rest was employed between each set (Willoughby et al., 2003). Subjects were required to refrain from strenuous exercise 3 days prior to the exercise bout. Indirect markers of muscle damage including MIF, KROM, SOR were assessed at 12 hours posteccentric exercise and every 24 hours thereafter for 5 days (Rawson et al., 2001). Blood samples were obtained prior to each eccentric exercise bout and also at 12, 24, and 48 hours post-exercise. After 30 days of supplementation, on day 31 (longer-term effect), subjects repeated the knee extension eccentric exercise protocol on the non-dominant leg to counteract the repeat bout effect. To determine the correct eccentric load, the concentric 1-RM of the non-dominant leg was assessed on day 21 of the supplementation period, in addition to all other measures, following procedures previously described. Measurements for indirect markers of muscle damage on the nondominant leg were repeated at 12 hours post-eccentric exercise and every 24 hours thereafter for 5 days (Rawson et al., 2001). Blood samples were obtained prior to each eccentric exercise bout and also at 12, 24, and 48 hours post-exercise. Subjects were instructed to consume a normal mixed diet throughout the duration of the study. During the 36 day study period, subjects completed four, 3-day dietary recalls for analysis of nutrient intake. Additionally, subjects were required to refrain from any additional strenuous activity (increasing exercise duration, intensity, beginning a new exercise regimen, etc). Normal daily activities and/or exercise were permitted.

Statistical analysis

Before analyses of the dependent variables, independent group t-tests were performed to ensure that the creatine and placebo groups were similar across diet. Analyses were preformed individually for the acute and chronic conditions. For both conditions, 2 X 7 ANOVAs with time as the repeated factor were computed to examine interactions or differences among the independent variables. The independent variables included the treatment groups (creatine or placebo) and time (pre to day 5). The dependent variables were MIF, KROM, and SOR. In addition, 2 X 4 ANOVAs with time as a repeated factor were computed for LDH and CK for both acute and chronic phases. The levels for time included pretest up to 48 hr. The alpha level was set at 0.05 and when post hoc analyses were performed, the Bonferroni adjustment was used to adjust for multiple analyses. Results

Results

The independent group t-tests for dietary intake of carbohydrate, protein and fat was not significantly different (p > 0.05) for the two groups. It was therefore determined that the groups were similar for dietary intake

Acute condition: No significant (p > 0.05) difference or interaction was found for KROM. For MIF and SOR only significant (p < .05) time differences were found. With respect to MIF, 12 hr was significantly less than days 3, 4, and

5. For SOR, pre test scores were significantly less than hr 12, 24 and 48; 12 hr was significantly greater than days 4 and 5. In addition, 48 hr was significantly greater than days 3, 4, and 5; and lastly, day 3 was significantly greater than days 4 and 5. LDH and CK were not significantly different across time or group (p > 0.05

Chronic condition: KROM, and LDH were not significantly (p > 0.05) different with respect for group or time. SOR was significantly (p < 0.05) different across time. Pre test scores were significantly less than hours 12, 24, and 48. Hour 24 was significantly greater than day 5; and hr 48 and day 3 were significantly greater than days 4 and 5. CK was significant (p < 0.05) across time. Pre test scores were significantly less than hours 12, 24, and 48.

For the chronic MIF data, one subject was eliminated for the analyses. Values for the subject were not considered within normal values for MIF. For MIF there was a significant (p < 0.05) time and treatment effect. For the time effect, MIF scores were significantly lower at 12 hours versus hours 24 and 48 and days 3, 4, and 5. Hour 24 MIF scores were significantly lower than days 3, 4, and 5. At 48 hours MIF scores were significantly greater than at 12 hours and days 4 and 5. On day 3 MIF scores were significantly greater than at 12 and 24 hours. On days 4 and 5 MIF scores were significantly greater than 12, 24, and 48 hours. For the treatment effect, MIF scores for the creatine group were significantly greater versus the placebo group.

Discussion

This investigation examined the acute and longer-term (chronic) effects of creatine supplementation on exercise-induced muscle damage. Anecdotal reports have indicated that individuals supplementing with creatine have a decreased recovery time during and following exercise, subsequently these individuals report greater/more effective exercise sessions. The consequences of exerciseinduced muscle damage particularly that of eccentric exercise, include a myriad of events that lead to reductions in muscle force, increased soreness, and impaired muscle function (Thompson et al., 2001). Therefore strategies utilized to reduce the negative effects of exercise-induced muscle damage would have great benefit to those wishing to maximize performance.

As a result of exerciseinduced muscle damage, there is injury to the cell membrane which triggers the inflammatory response leading to the synthesis of prostaglandins and leukotrines (Connolly et al., 2003). Additionally, alterations in sarcolemmal and sarcoplasmic reticulum membranes are evident. This damage may result in increased intracellular calcium levels which may be associated with muscle degradation. As such, ingestion of exogenous creatine may provide protective effects via increased phosphocreatine synthesis which may aid in stabilizing the sarcolemmal membranes and thereby reducing the extent of damage (Rawson et al., 2001).

In the current investigation only MIF following the chronic condition resulted in creatine having greater MIF versus placebo. This suggests that the creatine supplementation may reduce the extent of muscle damage when supplementing for more than 30 days. However, since no other indices of muscle damage resulted in differences between creatine and placebo, it is plausible that since these subjects were active males, that an ergogenic effect of creatine supplementation may have occurred. Previous investigators have reported increases in muscle fiber size and molecular changes with 12 weeks of creatine supplementation (Volek et al., 1999; Willoughby and Rosene, 2001). These investigations incorporated a resistance training program that contributed to the resultant changes. In the present investigation subjects were not required to refrain from training, therefore there was the potential for similar ergogenic effects. The resultant muscle force differences in the chronic condition support an ergogenic benefit, while the results from the acute condition are similar to previous reports with short-term supplementation (Rawson et al., 2001).

Neural factors such as enhanced neural recruitment patterns, enhanced motor unit synchronization and increased excitability of the ?-motor neuron have been attributed to strength gains early in a training program, the first 6-8 weeks. In addition, there appear to be intramuscular structural adaptations, including muscular hypertrophy and fiber type conversion (type IIb converts to type IIa) that occurs during 6 weeks of training (Staron et al., 1994). Creatine supplementation has been found to enhance intramuscular adaptations to strength training both at the fiber and molecular level (Volek et al., 1999; Willoughby and Rosene, 2001

In the present investigation, it is plausible to expect that increased MIF scores resulted in part due to neural adaptations. However, the creatine group exhibited a greater increase in MIF versus the placebo group in the chronic condition. Therefore an ergogenic benefit of creatine supplementation is the most plausible explanation for differences in MIF. Ingalls, Warren, and Armstrong (1998) reported that decreased muscle force following muscle damage is a result of proteolysis at days 14 and 28 post damage. Early decrements in force (within 5 days of damage) were not attributed to proteolysis. The MIF differences between Cr and P conditions at 30 days post damage may be explained by enhanced protein synthesis versus degradation, most likely within the MHC as previously reported (Ingalls et al., 1998; Willoughby and Rosene, 2001

Previous research has shown positive effects of creatine supplementation on muscle protein synthesis (Willoughby and Rosene, 2001). In the event that there is increased protein synthesis, and therefore reduced proteolysis, then creatine supplementation may have a positive influence on performance when muscle damage occurs. Traditional supplementation protocols have been utilized to rapidly increase muscle creatine levels (Harris et al., 1992; Hultman et al., 1996) and then maintain these levels (Robinson, 2000). Therefore, the protocols have been divided into a loading and maintenance phase. The loading phase is incorporated to rapidly increase muscle creatine levels by as much as 20%.(Harris et al., 1992). The maintenance phase allows for these increased muscle creatine levels to remain for the duration of supplementation. Any positive effects of creatine on the attenuation of muscle damage may be found under such supplementation conditions.

Indices of muscle damage, other than MIF, did not differ between the creatine and placebo conditions. However, the resultant time effects were consistent with the progression of recovery from muscle damage. It has been shown that muscle creatine levels show increases in just 2 days (Vandenderghe et al. 1999) and that signs and symptoms of muscle damage present within 48 hours of the event (Connolly et al., 2003). In the present investigation under both acute and chronic conditions there was evidence of symptoms of muscle damage within the 48 hour period, particularly SOR. These findings are similar to Rawson et al., 2001 who reported symptoms of muscle damage however, no difference between creatine and placebo groups following 5 days of creatine supplementation at 20 g.d-1.

The elevations of CK during the chronic condition may be indicative of using the non-dominant leg for the subsequent muscle damage bout. Increased CK in blood is a result of eccentric exercise which is unfamiliar to the muscle or muscle group, (Clarkson and Tramblay, 1992; Rawson et al., 2001) therefore CK elevations in the non-dominant compared to the dominant leg would be expected. Additionally, the CK elevations in the chronic condition suggest increased sarcolemmal or sarcoplasmic reticulum membrane damage. Since the non-dominant leg was used to induce muscle damage in the chronic condition, increased CK is most likely due to greater sarcolemmal and sarcoplasmic reticulum membrane instability as a result of mechanical stress from the eccentric exercise (Rawson et al., 2001).

Conclusion

In summary, short-term creatine supplementation did not appear to attenuate the effects of exercise induced muscle damage when compared to placebo treatments. However, the long-term effects appeared to have had an ergogenic effect on muscle when muscles were subjected to isometric force development. Anectdotal reports of attenuation of muscle damage and decreased recovery time may be associated with the increased energy availability of PCr associated with creatine supplementation, as well as the possible molecular changes in muscle. The eccentric protocol utilized in the current investigation and that of Rawson et al., 2001 were designed to create situations of significant muscle damage. Therefore the possibility exists that creatine’s ergogenic effects on muscle may require greater than 7 days to positively impact muscle damage. Future studies may need to focus on lesser amounts of exercise induced muscle damage, such as may occur with regular weight-bearing athletic type activity, for short-term creatine supplementation protocols to see a potential benefit of creatine supplementation in decreasing recovery time and attenuating exercise induced muscle damage. In addition, longer-term supplementation protocols should investigate additional muscle performance measures, such as dynamic strength, to determine if muscle damage is attenuated or is recovery time decreased due to the ergogenic effects of creatine supplementation.

Acknowledgments

The creatine and placebo supplements were provided by AST Sports Science, Golden, CO, USA. All experimental procedures comply with the current laws of the United States.

Key points

  • Eccentric muscle actions highly associated with exercise induced muscle damage.
  • Creatine supplementation has ergogenic effect to increase protein synthesis.
  • Creatine supplementation does not attenuate exercise induced muscle damage with short term supplementation (7 days).
  • Increased maximal isometric force seen with creatine supplementation after 30 days following exercise induced muscle damage.
  • Ergogenic effect of creatine supplementation may contribute to reduced exercise induced
  • muscle damage.

Recovery training: the importance of recovery and various recovery strategies you should implement The importance of recovery for sportsmen and women of all disciplines James Marshall MSc, CSCS, ACSM/HFI, runs Excelsior, a sports training company

When planning training programmes for athletes, it is easy to write down sets, reps, times, volumes, intensities and loads. However, structuring a recovery programme to effectively allow adaptation to take place between training sessions is a lot trickier, as James Marshall explains

Before we look at how recovery can be optimised, it’s important to understand why it’s important. This is crucial for both coaches and athletes; coaches because they are going to have to plan time and resources to assist recovery, and athletes because they are going to have to implement the strategies. According to ‘supercompensation theory’ (see figure 1), after the body has been exposed to a stressful situation, providing that adequate recovery has taken place, it will adapt and become stronger(1). Without further exposure to this stimulus, the body will soon return to its previous state. However, if further training takes place during the supercompensation phase, then more work or higher intensities can be tolerated. But if training takes place too soon, recovery is incomplete, less work can be done and the athlete risks fatigue, injury or burnout

Fatigue comes in different forms, including central, peripheral neural, hormonal and psychological; the recovery process therefore needs to target all these different areas. Different aspects of fatigue require different amounts of recovery, and it is very difficult to balance these recoveries. For example, competing in a final of a competition may actually be physically easier than a training session, but the emotional, psychological and hormonal stress will be much greater and this should be taken into account when planning post-competition training.

Where recovery is useful is in trying to reduce the time between training stimulus and supercompensation. Inadequate recovery strategies will mean that you’re not prepared to train at the next session; instead of enhancing training status, another session actually puts you back. There are some times when inadequate recovery might be planned, such as on a training camp for a few days, but this must then be followed by a few easier days to allow supercompensation to take place. However, during hard competitive phases of the season, time might be one thing the coach doesn’t have, so enhancing the recovery becomes crucial.

Comparing recovery strategies

Which recovery strategies are best in a realistic training environment? Researchers from Australia looked at recovery interventions on netball players following a simulated netball circuit training session(2). The players performed the same circuit on two consecutive days and followed one of four recovery interventions:

  • Passive recovery;
  • Active recovery;
  • Cold water immersion (CWT);
  • Contrast water therapy.

All four of the interventions were performed for 15 minutes, with the passive recovery group sitting still for all that time. The active recovery group performed low intensity exercise at 40% of their maximum oxygen uptake (VO2max), while the cold water immersion subjects sat in a cold bath (9.3C) up to the top of their hip bone for 5 minutes, followed by 2.5 minutes out of the bath — repeated twice. The contrast water therapy group also sat in a similar temperature bath, but this time for 1 minute, then had a warm shower (39.1C) for 2 minutes and did this five times in total.

Recovery was assessed by subsequent performance (20m sprints, vertical jumps and total circuit time) as well as measurements of lactate, heart rates, ratings of perceived exertion and muscle soreness. The results showed that there was no difference statistically in performance on the two circuits or on the physical measurements for any of the recovery interventions (the fact that there was a whole 24 hours of recovery time between the two sessions may account for this, and that the circuit was challenging, but not maximal).

However, there was a difference in perceptions of recovery; the subjects who did cold water immersion and contrast water therapy perceived themselves as better recovered. This may be important as it shows the relevance of mental recovery in the process. It also highlights the need to keep recovery strategies tuned to the individual.

Compression clothing

Another study on netball players also found no difference in performance following an intervention — this time using compression tights(5). The subjects did five sets of 20 drop-jumps from a 60cm height, followed by an immediate jump up as high as they could, with a 2-minute rest between sets. The two recovery interventions were either wearing compression tights for 48 hours afterwards or just wearing normal clothing.

The results showed that there was no difference in performance between the groups in subsequent sprint tests; both groups ran slower 48 hours after the drop jumps than before. However, perceived muscle soreness was lower in the compression garment group compared to the control group after 48 hours. There was also a slight reduction in CK levels (see box 2, below) in the female compression garment group after 24 hours compared to the controls, but no difference after 48 hours. Moreover, subjects who used compression tights reported that the tights were uncomfortable at night, as they raised their body temperature and disrupted their sleep.

By contrast, a study on New Zealand provincial rugby players found that compression garments did help reduce CK levels compared to passive recovery(7). Contact sports such as rugby and boxing have been shown to produce higher levels of CK following the match, than in similar training sessions with no contact(8,9) so CK is definitely a useful marker of measuring fatigue in these sports.

The rugby players followed one of four recovery protocols post match:

  • Passive recovery (sitting on the bench for 9 minutes);
  • Active recovery (7 minutes’ cycling on a stationary bike at 80-100 rpm);
  • Contrast water therapy (CWT — 3 sets of sitting in a bath of cold water [8-10C] for 1 minute followed by hot water [40-42C] for 2 minutes);
  • Compression garments — wearing compression pants for 12 hours postmatch.

CK levels were measured immediately post match and then subsequently at 36 and 84 hours post match. A comparison between peak levels and the levels at 84 hours was then made. The fastest recovery was found in the active group, with the CWT and compression groups also showing fast levels of recovery. The passive condition showed the slowest level of recovery by some degree.

The nature of science investigations is to isolate one intervention at a time and to compare each intervention against a control group. However, it’s interesting to speculate if a combination of active recovery and CWT or compression garments worked better than one intervention alone. What is clear in this study was the short duration of all the post-match interventions; it could be surmised that a longer active recovery session would have resulted in an even further reduction in CK levels at 36 and 84 hours post match.

Implementing a recovery strategy

Coaches and athletes tend to fall into one of two camps: the ‘throw every resource we have at this, and implement everything together’ camp or the ‘let them get on with it’ camp. If you are a recreational athlete who trains on a Tuesday and Thursday, and competes on a Saturday, then you will have about 48 hours between sessions to recover naturally. Muscle glycogen can be restored through normal eating and most indicators of muscle damage such as creatine kinase will probably have returned to normal levels before your next training session. In short, recovery will likely take care of itself!

However, if you train or compete more frequently, then you’ll need to do something to aid the recovery process. If you’re a coach, it is probably best to have some ‘non negotiable’ recovery processes in place for the whole team:

  • An active warm-down immediately after competition/practice has finished;
  • Fluid and fuel replacement within 15 minutes of finishing the session;
  • Some form of water therapy such as showers, contrast showers, contrast bathing, depending on facilities;
  • A proper meal within two hours of finishing.

Depending on budget and the distance to travel home, compression garments could also be useful. Wearing compression tights is easy enough (although there is an initial cost) and many athletes like the comfort of wearing them. However, they shouldn’t be worn at night because they can potentially disrupt sleep, which will hinder recovery. Table 1 shows the pros and cons of different recovery strategies.

Other factors

The importance of nutrition in recovery is beyond the remit of this article (this topic has been covered extensively in previous issues of PP). However, it’s important to understand that carbohydrate, fluid and protein replacement is critical for speedy recovery. So, when looking at the physical aspects don’t forget that they will be more effective with fuel and fluid intake. The importance of sleep should also not be overlooked; if all else fails, getting a good night’s sleep should be first in the athlete’s mind!

Remember, too, that the psychological and social aspects of recovery are also important in the recovery process. The individual’s social and psychological preferences when recovering need to be taken into account. For example, some athletes might relax by taking a trip to the park as a group. For others, spending even more time with teammates could be an additional stressor and hinder the recovery process, so quiet time with a book or listening to music may be more appropriate. So-called ‘team building’ sessions maybe counterproductive for some athletes; stress can be created if these sessions take them away from their home environment for too long, causing relationship stresses, or placing them with teammates for longer than usual!

The use of CWT is also interesting, as plunging into a cold bath may not be to everyone’s tastes and could add to the stress of post-match trauma. The sudden immersion into cold water stimulates the sympathetic nervous system and actually invigorates the athlete. Gradual cooling may be more suitable for some because it stimulates the parasympathetic system and will calm the athlete down(10). It’s also worth adding that although other forms of heat therapy, such as saunas and jacuzzis, may feel relaxing if used a few hours after training, they should not be used immediately afterwards as they encourage dehydration.

Adaptation and personal preferences

As with any other form of training, adaptation to the recovery strategies will take place. The more you use a form of recovery, the more likely it is that after a certain amount of time, you will adapt, which will reduce the response and benefits. Instead, coaches should get their athletes familiar with recovery strategies such as CWT, but only in small doses. Then at the time of most need, such as in a tournament phase, you can use it much more intensely so that it stimulates the recovery process.

However, it’s important to emphasise that a successful recovery strategy needs to consider the athlete’s personal preferences, with the athlete being involved in planning their recovery strategies throughout the season and offseason. Of course this has to be done in conjunction with the coach and other support staff, but the athlete has to be familiar with and 100% comfortable with the choices made. If a coach introduces new methods the day before a competition, it will only lead to more stress for the athletes.

Summary

Recovery is essential in order to allow the body to adapt to the stresses of training and competition. Simply doing nothing may be okay for those who train two or three times a week, but for more serious athletes and those involved in contact sports, a recovery plan has to be put into place. The other tools here are important, but without good nutrition, sleep and relaxation they will be of limited value.

References

1. Bompa, T. Periodization: Theory and Methodology of Training. Champaign, IL: Human Kinetics (2001)

2. JSCR 23 (6), p 1795-1802 (2009)

3. Kellmann, M. & Kallus, K.W. Recovery-Stress Questionnaire for Athletes; User manual. Champaign, IL: Human Kinetics (2001)

4. JSCR, 22 (3), p1015-1024 (2008)

5. JSCR 23 (6), p 1786-1794 (2009)

6. Isr J Med Sci, 31, 698-9 (1995)

7. Br J Sports Med 40, p260-263 (2006)

8. Med J Aust 1 p467-70 (1981)

9. Int J Sports Med 6 p234-6 (1985)

10. Kurz, T. Science of Sports Training. Island Pond, VT: Stadion (2001


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