What the experts say
Nigel Hetherington reviews the latest research material relating to coaching, exercise physiology and athletic development.
To quote a recent review 'the upward trends in athletic performance can be observed in a wide range of sports from sprinting to golf. There are ranges of factors that contribute to these observed increases. Some, such as improved levels of fitness and technique, are related to the human element of competition. Others are associated with sports equipment design and the construction materials. In field athletics, for example, different factors have contributed to improvements in performance in different disciplines: events such as the hammer are dominated by the human element, whereas the pole vault is strongly affected by materials technology. Enhancement of performance through materials technology is not without its critics, particularly in sports such as golf and tennis. Governing bodies are becoming increasingly proactive in the specification of detailed regulations for the design and construction of sports equipment. However advances in materials technology can also make sport more enjoyable for novice to intermediate athletes, resulting in increased participation (as well as increased health and wealth for society as a whole)'.
The bottom line here is that a whole array of mechanical ergogenic aids that serve not only the elite performer in search of the elusive 'sporting edge' but also the would-be beginner are set to become big business. One such mechanical aid that has achieved much publicity over the last 10 years or so is the personal heart rate monitor. In the last issue of Successful Coaching (12, 2004) Ken Grace responded to a reader's letter on this subject with some excellent guidance. In further support of Ken's closing paragraph a quote from the instructions accompanying a monitor acquired a couple of years ago are interesting 'The contact between the skin and the belt (i.e. transmitter pad) is not to be disconnected through bigger movements such as deep breathing.' Hmm?
While on the subject of heavy breathing, exposure to elevated oxygen levels particularly in a hypoxic tent environment, prior to competition has been used as a means of improving performance. However, a recent paper found simply that a single exposure to 95% oxygen at normal pressure for 90 minutes had no measurable effect on VO2max assessment straight afterwards so it may be best to seek further expert help before you rush out to buy that oxygen cylinder or hypoxic tent!
According to the authors, over the years since 1966 there have been many attempts to train the muscles used in the breathing process (so-called 'inspiratory muscle training' or IMT). Pressure threshold loading has been found to be the most successful means in clinical situations. This paper describes a novel IMT device trademarked 'Powerbreathe ' available as a class 1 medical device with an apparently proven track record in IMT. A later paper from a group in Australia adds a cautionary note to this form of training since they conclude that sensory rather than respiratory muscle conditioning may be an important mechanism by which whole-body endurance is increased.
A fascinating and yet simple study based on two parallel groups of male cross-country skiers showed that by completing an 8 week program consisting of 3 sets of 6 highly event-specific exercises at 85% of IRM (one rep maximum) significant gains can be made to rate of force development and aerobic endurance as measured by time to exhaustion on a double poling ski ergometer. The time to exhaustion improved by over 20% and the time to peak force was reduced by up to 60%. The emphasis in the training was for each skier to aim for a maximal rate of concentric muscle action by applying the greatest force possible to overcome resistance based on a cable pulley system designed to simulate the double polling action.
A paper that will bring a welcome smile to the face of all male endurance athletes concluded that when a group of 10 male runners of average age around 60 was compared to a sample of sedentary and yet healthy males of average age around 58 that the runners (average over 40 miles per week) came out on top. The runners produced higher average and peak levels of human growth hormone (peak 5.25 vs. 2.10 mU/l) during a two-hour recovery period following measurement of VO2max where the runners attained 34.91 vs. the sedentary individuals 22.36 l/min/kg. Sex hormone binding globulin and testosterone were also significantly higher in the runners. The suggestion is therefore that such activity can help to counteract the normal decline of growth hormone with ageing.
A wealth of literature exists on the detrimental effect of elevated core body temperature on endurance performance. This is typified by performance in Tropical zones where the mean temperature is around 30ºC and humidity is also very high. A recent article reports that power output can be improved by up to 7% in activities acting up to an hour in such conditions. Various methods for reducing core temperature are reviewed. The effect is believed to function through the reduction in core temperature creating a greater heat storage reserve - function tends to fall dramatically once core temperature reaches 40ºC - thus allowing a higher work rate to be performed before elevated core temperature limits performance. A follow-up comment reinforces the findings and also highlights the importance of testing any such strategies out of competition to identify the most suitable and practical method for each athlete.
An earlier paper looking at dynamic leg press exercises in 6 female volleyball players of national standard demonstrated that the use of 'whole-body vibrations' before performing the lifts led to a measurable increase in velocity, force and average power output. The perhaps somewhat inconclusive explanation was given as being down to 'neural factors'. A more recent paper has shed further light on this where the authors looked at a hard-squatting exercise with and without vibration at 26Hz with performance tests being run before and after on a group of 19 healthy young individuals divided into two groups. Both groups performed similarly in the tests before and after and during the exercise itself. Most interestingly though the group that had undergone the vibration treatment during the hard-squatting regime showed a significant increase in muscle activity associated with the vastus lateralis (one of the quadriceps muscle group mainly functional in extending the leg from a fully flexed knee position). Activity was recorded using electromyography. The specific conclusion from these data is that the vibration treatment led to a change in neuromuscular recruitment patterns, which apparently enhanced neuromuscular excitability. This could have an impact on training regimes in the future.
A study reporting on high-intensity training based on 30s duration supramaximal cycling sprints with two different groups following a different rest period regime has been published. In the research two randomly established groups of 5 males performed the 30 seconds test before and after normal training. One group (short program - SP) trained every day for two weeks while one group (long program - LP) trained every third day for 6 weeks. While the SP group showed enhanced levels of key biochemical markers including lactate dehydrogenase (active in metabolizing lactate) it was only the LP group that showed a marked increase in performance suggesting that the muscle fibre fatigue and injury in the SP group had not had time to recover in order to yield a benefit from the next training session.
This fully supports the belief held by many coaches that high intensity training sessions must be interspersed with low intensity or rest days in order to allow the training effect to occur.
Another report using different recovery times during repeated cycle sprint of 8 seconds duration demonstrated that both 15 seconds and 30 seconds recoveries were inadequate to allow for maintenance of a peak power output above a certain level but that with recoveries of 1 or 2 minutes power output could be maintained for each sprint.
A part-finding from a study based on 8 females performing a series of cycle sprint tests showed that when two 30 seconds maximal cycle sprints were performed - the first against a greater resistance and therefore slower pedal rate (by ca. 26%) than the second - the peak power output in the second sprint was statistically greater (442W vs 402W) even though the muscle metabolite response profile was similar. The metabolite data and additional findings reported in the paper seem to suggest that recovery of power is not exclusively determined by muscle metabolites. We all know and understand that warm-up leads to elevation of muscle temperature and enhanced muscle performance. This result, however, appears to suggest that in order to attain true maximal output a maximal 'rehearsal' effort performed within a very close timeframe (i.e. within minutes), possibly against an increased resistance relative to the actual attempt, may yield a subsequent competition performance benefit for some power athletes.
Despite the important 'feel good' factor that many athletes experience following massage therapy and the excellent review of the potential benefits of such treatment reported by Jon Gestl in Successful Coaching (Issue 12 May 2004) a very recent publication challenges the widely reported findings that massage serves to clear metabolites and hence reduce the time between useful workouts and also that massage facilitates an increase in power output through increasing the range of movement and flexibility. Following a standardized warm-up the study is based on data from 9 male games players performing 6 standardized 30 second high intensity exercise bouts on cycle ergometers with 30 second active recoveries. Ending with 5 minutes of active recovery and then 20 minutes of either supine rest or leg massage the subjects then performed a 30 second Wingate test after a standardize warm-up. No difference was shown between the groups for blood lactate or maximum power between trials. However, a lower fatigue index was observed in the massage group that warrants further investigation.
A second report by authors from the same team as above questions the requirement for physiotherapist level trained expertise to provide massage that can only be demonstrated to provide a 'feel good' factor. They argue that specialist sports massage staff should be used for these purposes.
Though not classically considered as ergogenic aids, both the wind and the altitude play a major part in many performances. A recent studybased on 110m hurdling attempts to create a more meaningful comparison of many of the current elite senior men's 110m hurdle best performances by calculating out the effect of altitude and wind. The wind factor has been reported previously for the 100m event as being equivalent to a decrease in time of 0.10 second for a wind factor of +2.0m/s. The findings for the hurdles are as high as 0.19 second for the same wind speed. For example, the author's model would have Colin Jackson's World record modified to 12.98 seconds from 12.91 for comparison purposes based on the altitude of Stuttgart (250m) and the +0.5m/s wind. Jackson's 12.97 seconds run in Sestriere (2065m) but with a wind of -1.6m/s would, interestingly, become 12.90 seconds. Unfortunately, the reported findings come under fire from the author of the original paper and so the debate may continue for some time.
Finally, in the last issue of Successful Coaching Gordon Manning unwound the mystery of hypnosis and explained why the power of the mind is so important in performance. Our last paper reviewed in this issue serves to underpin the important role the coach plays in creating and maintaining a motivational environment and how this impacts on success for the athlete. Elite athletes were used in the study and the outcomes highlight that the athletes perceived that a high mastery climate and a low performance climate was highly beneficial to them. The message appears clear - seeking to perform the perfect effort through total mastery of the event is more likely to produce the dream performance than focusing on the outcome of that performance. This is probably the highest order psychological ergogenic imaginable - but then if you are reading this you probably already knew that.
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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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