What the experts say
Nigel Hetherington reviews the latest research material relating to coaching, exercise physiology and athletic development.
I am often asked my views on creatine supplementation for athletes. My views are my own and remain unchanged. Here is what the science seems to be saying. The key points from a major review on the use of creatine were as follows:
Despite the literature clearly showing that a brief (5 day) high-dose creatine-loading phase is sufficient to saturate muscles with creatine, survey data indicate that athletes often ingest creatine supplements for weeks or months, rather than for several days before an athletic event. It has been reported that baseball and football players most often ingest creatine in the off-season, which is the time of year when athletes undergo training to increase strength and/or body mass for the forthcoming competitive season. Thus, rather than ingesting creatine acutely to improve performance at a particular athletic event, many athletes use creatine chronically in an effort to increase muscle strength, muscle size, and body mass during training.
A recent single study looked at the impact on anaerobic work capacity (AWC) after two or six days of supplementation with creatine at 4 x 5g per day versus a dextrose placebo. Results showed a 13-15% increase in AWC in both men and women.
The overall conclusion was that the performance of some, but not all, individuals can benefit from creatine supplementation; there is no "magical" effect for everyone. If only some individuals experience a benefit, then do these individuals have an unfair advantage in sport performance? The ethical issues associated with creatine supplementation remain unclear. In the world of swimming one paper argues there has been little or no evidence demonstrating benefits to swim performance either in a single sprint swim or repetitive interval swims. The paper does report that improvements have been measured on a swim bench ergometer for power development and suggests that how this improvement in power output might transfer to the water is uncertain. I am left very confused here! Does swimming not have a power output function that relates to swimming speed - readily measurable in sprint swimming? Not quite sure how a swimmer propels themselves through the water if there is no relationship here.
A complementary review to the first added the following comments:
I would probably rest my case on the last point plus one or two caveats - long-term commitment to a progressive training program that is designed for each athlete and the motivation to train and compete. These by far outweigh the benefits that any supplement can provide. Furthermore, many do not consider the potential impact of such supplementation, for example, if chronic ingestion allows the athlete to complete more training than their body is able to naturally respond to in terms of overload / adaptation then somewhere along the line there is going to be an unwanted effect - possibly injury or more subtly, over-training syndrome and fatigue. As the saying goes 'There are no short-cuts to any place worth going.' I still have not met any performer in any sport who has made it to the top without talent and hard work and, in the main, supported by great coaching. It does appear that the advantages that such substances can produce through acute supplementation can impact on performance on the day when a little can mean such a lot!
Of course the real problem here is deciding what is a supplement and what is not. Caffeine was removed from the WADA list of banned substances a couple of years ago, possibly due to conflicting evidence on the ergogenic effect on prolonged, sub-maximal exercise. A recent publication may bring that decision into question, but from a different perspective. A study examined the benefits of 6mg / kg body weight versus a placebo taken 60 minutes before exercise on male team-sport athletes when completing cycle ergometer sprint repetitions - 2 sets of 18 x 4 second sprints with 2 minutes active recovery. The outcome was very interesting in that the caffeine group showed an 8.5% higher level of sprint work completed in the first set and still 7.6% higher in the second set while mean peak power was 7.0% and 6.6% higher respectively. A specific study involving caffeine also examined its effect on leg muscle pain in females during moderate intensity cycling exercise with perceived pain levels being almost halved with a 5mg / kg body weight relative to placebo.
Carbohydrate loading is another area well covered in the endurance literature but less so in the power domain. An interesting study looked at the effect of high loading (6.5g / kg body weight) versus moderate loading (4.4g / kg body weight) on repetitive jump squat power performance over 4 sets of 12 maximal effort jumps with 2-minute recoveries. The results showed a decline in performance with time independent of the carbo-loading level and there was no significant difference in power performance. Blood lactate levels were similar in both cases. So it is strong coffee with added creatine, but with no added carbohydrate for everyone then?
It is right that appropriate professional organizations should seek to challenge existing rules and regulations within sport. A recent publication has raised a question concerning the use of ß2 agonists and the current criteria for use. Effectively the report concludes that the current guidelines may be preventing fair play rather than promoting it since one third of the diagnosed asthma sufferers used in the experiment would be denied the opportunity to receive the most effective therapeutic action under current guidelines and would not receive therapeutic exemption for the use of ß2 agonists.
A potentially useful application of physiological data has been reported for soccer players. Four different forms of practice were identified based on measured heart rate zones and the associated blood lactate levels - friendly matches, modified games, tactical training and technical training activities. Blood lactate levels of 2 and 4mM were used as the reference points and the proportion of time players spent in each lactate zone calculated from their heart rates during exercise in the different activities. Armed with this information coaches can now plan heart rate zone activities to meet intensity requirements and keep a log of estimated exercise intensity during training.
Going on to relate specific physiological data to performance is not a new concept but it seems to me that we have still a long way to go in terms of making these data specific enough to individual sports or events to be particularly useful. However, one study has moved toward this goal with a specific experiment based on 3000 metre running performance. Using 16 experienced and trained triathletes a battery of measurements were conducted. The findings were that peak treadmill running velocity during a VO2max test alone accounted for 82.3% of the variance. Adding in running velocity at lactate threshold and peak lactate concentration elevated the predictive power to 93.6%. It was also obvious from this that both aerobic and anaerobic parameters are important measures of 3000 metre performance.
Analysis of sprint patterns in rugby union matches has led to a better understanding as to what form of speed training players from different match positions should undergo. Interestingly forwards commenced sprints from a standing position most frequently (41% of the time) whereas backs started from standing 29%, walking 29%, jogging 29% and striding 13% of the time. Both sets of players reached speed in excess of 90% maximal speed during a game though backs were almost twice more likely to attain this than forwards. Clearly backs need to undergo specific sprint training. However, the similar distribution of overall velocities for both forwards and backs suggests that both sets of players should undergo specific acceleration training and maximal speed training utilizing a variety of start speeds to mimic movement patterns of competition.
Another paper appeared to add to the stretching debate. This one examined the effect of different stretching routines prior to high-speed motor capacities important to soccer playing including 10m sprints, 20m flying sprints, agility performance etc. There seemed little difference between no stretching and static stretching. However, there was a consistent difference between performance following a dynamic stretch protocol and static stretching of the order of 1 to 2% in favour of dynamic warm-up.
A paper that looked at recovery intervals when performing bench presses found that from a variety of repetition and set regimes the power output was maintained if the recovery between individual reps was increased or smaller sets were used when compared to more traditional sets of 6 repetitions performed consecutively. Not surprising at all since the predominant energy system here is the ATP-CP system that will recover significantly provided a few extra 10's of seconds are allowed between repetitions or lesser reduction takes place through smaller sets. It is the outcome of such training that needs to be the measure. I guess the coach and athlete have to think this one through for their particular sport and training needs.
Found another paper on one of my pet-topics - contrast preloading explosive work! I have reported earlier on this from an anecdotal perspective and found a reference supporting observation. Now here's another. This study looked at the effect of preloading on a jump squat and found a significant enhancement compared to no preloading or simply a repeat of the same activity. The conclusion was that a single set of preloading exercise enhances performance during a lower body explosive power training session. However, optimal effect may not occur until midway through a session.
Another study compared the benefits of low, moderate and high training volume sessions all at high relative training intensities for trained junior weightlifters and found that moderate volume, high intensity session produced the best return.
And finally, after all that training and coaching maybe it is your pleasure to take a break on the golf course? A recent paper, however, reports that not only do previously published findings on the benefits of flexibility training etc. hold true for increased club head speed (leading to up to 4.9m increases in driving distance in this case) hold true but that putting distance control (for men) and consistency (men and women) also benefit. The golf club is no place to relax then !
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About the Author
Nigel Hetherington is the Head Track & Field Coach at the internationally acclaimed Singapore Sports School. He is a former National Performance Development Manager for Scottish Athletics and National Sprints Coach for Wales. Qualified and highly active as a UK Athletics (UKA) level 4 performance coach in all events he has coached athletes to National and International honours in sprints, hurdles as well as a World Record holder in the Paralympic shot. He has 10 years experience as senior coach educator and assessor trainer on behalf of UKA. Nigel is also an experienced athlete in sprint (World Masters Championship level) and endurance (3-hour marathon runner plus completed the 24 hour 'Bob Graham Round' ultra-endurance event up and down 42 mountain peaks in the English Lake District). He is a chartered chemist with 26 years' experience in scientific research and publishing.
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