What the experts say
Nigel Hetherington reviews the latest research material relating to coaching, exercise physiology and athletic development.
'Are their limits to running World Records' is the provocative title to a paper that reflects on recent claims that in the future women will run faster than men. The claim was based on what the authors see as an oversimplification of trends. In this review of data using more relevant data analysis both long and middle-distance events were re-analysed from data collected throughout the 20th century. The final conclusion was that many of the established men's and women's endurance running world records are nearing their limits. As a result, women's times are unlikely to ever reach those achieved by men. Sounds like a challenge ladies?
A recent study looked at coordination patterns of flat breaststroke swimmers at different levels up to elite. Using video analysis, the researchers identified that at increasing swim speeds for race distances between 200m and 50m the trend was for shorter glide phases, more rapid stroke rates and shorter stroke lengths. However, in the elite swimmers, the glide time was significantly less at all speeds than in non-elite. This paper argues the point that developing the optimum technique for the event works and that the optimum technique for the flat breaststroke has been thus defined.
Reaction to different forms of training on aerobic power was investigated in 10-year old boys using a comparison between high-intensity interval training and moderate intensity continuous training. After an 8-week program involving either steady-state cycling at 80 to 85% of maximum heart rate or 30-second sprints on a cycle ergometer, the outcome was that the boys from the interval training sessions showed significantly greater improvements in a number of key physiological factors including ventilatory threshold.
but I did not say that I advise it!
A simple and yet interesting review of the practice of basketball coaches, operating at a national level in the US, in strength and conditioning training revealed that 19 out of 20 use Olympic lifts, all used plyometrics, 17 out of 20 follow a periodised training plan with their athletes. The survey might suggest that the coaches all follow a prescribed approach; that they are all acting in best faith using good practice or that through experience, they have all arrived at the same conclusion as to what actually works best. It does not guarantee that the approach is best for all athletes. The review does, however, also serve as a source of applied information and new ideas - great for the open-minded coach as well as the one who just wants to do what is proven.
A study revealed that not only does ingesting carbohydrate during prolonged cycle exercise attenuate the perception of exertion but that it also enhances feelings of pleasure during and following such physical exertions! The point is that it is 'how' an athlete feels that may be important in addition to 'what' they feel.
A paper I am still trying to get my head around reports that performing water-based plyometric training yielded improvements in vertical jump performance in female volleyball players not yielded from a parallel training program that used a stretching protocol. Both groups also took part in a traditional pre-season training program during the 6-week duration of the trial. After 4 weeks there was no difference but after 6 weeks the water trainers showed an 8% improvement in vertical jump performance. Given the potential for reduction in muscle soreness and load-bearing injury often associated with land-based plyometric training, the use of aquatic training is a well-worth investigation.
The impact of an 8-week training program on running economy in terms of the energy cost of running fast or slow has been investigated based on recreational runners. Data from the two-stage fitness test was collected at the start and after 4 and 8-weeks respectively. Maximum running time at v-fast was used as the performance measure. Energy cost was calculated from oxygen uptake above rest, blood lactate and speed. The results showed that while the maximum running time increased the energy cost reduced while running at the speed most commonly used in training. However, at v-fast, the energy cost can actually increase if the running time increases. This suggests that with novice athletes more energy is initially consumed at higher speeds with which they are unfamiliar relative to lower speeds. This is due to both the incomplete development of the energy pathway and correct running action. A related paper looked specifically at running 8000m at slow (70% aerobic threshold) and fast (90% aerobic threshold) speeds and concluded that though energy requirements differed at the two different speeds they were comparable on a relative basis. The faster run leads to the metabolism of greater amounts of carbohydrate whereas both runs consumed similar amounts of fats.
The impact of hydration status at reduced temperature and ambient temperature on endurance exercise has been studied. Subjects were exposed to 3hr passive heat stress at 45 deg Celsius. Half of the group was allowed to remain hydrated with consumption of fluids equivalent to 3% body mass while the other half were not allowed any fluid replenishment. Later subjects were exposed to either 2 deg Celsius or 20 deg Celsius for 1-hour. Subsequent 30-minute time trials revealed that the endurance performance for those exposed to reduced temperature and hypo-hydration lost less performance than those exposed to the higher temperature and hypo-hydration. The data demonstrate that hypo-hydration impairs endurance exercise performance in the temperate but not cold air but that cold stress alone does not.
A paper looked at anthropometric measurements and physical test results as to provide possible reasons behind the domination of sprinting by Afro-American and Caribbean athletes. In a study involving a comparison of Caucasian and Afro-Caribbean pre-pubertal boys of average age 11.49 years, the researchers revealed that there were no significant differences in sprint performance over 30m. Interestingly a vertical jump measurement was the main predictor of performance for the Caucasian boys while the stride number to height ratio was the main factor in predicting performance with the Afro-Caribbean boys. The latter group had better jump test results and ratios. It was hypothesized that despite the fact the Afro-Caribbean boys seemed to be endowed to run faster, they did not. It was proposed that this group was, unable to use their greater leg strength at this age to develop an optimal stride.
A series of papers have appeared looking at gastrointestinal problems and factors in relation to distance running. It has been reported that between 30 and 50% of participants experience one or more symptoms and that these symptoms are more prevalent in running that in other events involving less mechanical strain - e.g. cycling or swimming. The first study looked at symptoms and identified a broad spectrum. Very often athlete will undergo physiological adaptation to or caused by these factors - a fact that must be considered by medical practitioners when treating endurance athletes. In the second study health factors come under the microscope in relation to nutrition which can potentially positively and negatively affect the status. The impact of both heat exposure and water loss is also considered. In a further study the authors sought to examine the mechanisms behind gastrointestinal function in response to endurance exercise found from a review of the published literature. Key factors outlined included blood flow, motor function within the GI tract and hormonal messenger changes. Finally a major review paper examines the full range of gastrointestinal problems that may be experienced by distance runners including disease and other factors. With respect to diet, the pre-event meal may not critically assist performance but it does have the ability to harm performance. Care should be taken in making any dietary changes and last-minute changes should be avoided.
The response by a chronically fatigued body to abnormal exercise is reported in a study. The paper supports previous beliefs that immune deregulation at the cellular level is the main factor. Sufferers of chronic fatigue syndrome appear to potentially react negatively to abnormal exercise.
Finally, this month, as promised last month, I provide details from a major review paper looking at the effect of dietary supplements and sports performance. The paper reports that minerals are essential for a wide variety of metabolic and physiologic processes in the human body. Some of the physiologic roles of minerals important to athletes are their involvement in muscle contraction, normal heart rhythm, nerve impulse conduction, oxygen transport, oxidative phosphorylation, enzyme activation, immune functions, antioxidant activity, bone health, and acid-base balance of the blood.
The two major classes of minerals are the macro-minerals and the trace elements. The paper has a focus on the ergogenic theory and the efficacy of such mineral supplementation. Because many of these processes are accelerated during exercise, an adequate amount of minerals is necessary for optimal functioning. Athletes should obtain an adequate amount of all minerals in their diet, for a mineral deficiency may impair optimal health, and health impairment may adversely affect sports performance.
Iron and calcium are the two micronutrients most likely to be low in the diet, particularly in young athletes. A mineral deficiency may impair performance. Iron deficiency is a clear example of this in terms of the effect on endurance performance. Calcium deficiency may be an issue, particularly in female athletes. In contrast to this supplementation with magnesium, iron, zinc, copper and selenium does not appear to enhance performance in well-nourished athletes.
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About the Author
Nigel Hetherington was 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 British Athletics 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 British Athletics. 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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