What the experts say
Nigel Hetherington reviews the latest research material relating to coaching, exercise physiology and athletic development.
The northern hemisphere summer period has yielded some fascinating insights into coaching as published in the scientific literature over the last two or three months.
Launching straight in a paper from Canada reported on how unique geographical surroundings can affect coaching success. The author reports that elite coaches located in remote and rural locations, for instance, face unique challenges that differ from those experienced by elite coaches in large cities with greater population densities. As well as still requiring and demonstrating the key generic characteristics common to all elite coaches including being great teachers, leaders and motivators, coaches working in more rural environments tend to demonstrate a strong desire towards reaching personal success and above average leadership skills with athletes, the sport and the community.
Leadership was then better imparted to the athletes by selling their vision and inspiring them to pursue athletic excellence. Furthermore, problem-solving skills tended to be significantly higher, in response to the need to be creative with facilities and dealing with weather and travel, among other things. The findings lead to proposals regarding the development needs of aspiring elite coaches in such situations and the conclusion that specific support and development is required that is relevant to the environment in which the coach operates. This should influence coach education provision.
In the new 'genetic age' a paper that caught my eye looks at the shift from environmental to genetic factors and their influence on participation in sport. Based on a very significant survey of identical, non-identical and opposite gender twins the results demonstrated that between the ages of 13 and 16, environmental factors shared by children from the same family account for individual differences in sports participation (78 to 84%), whereas genes are of no importance. At the age of 17 to 18, genetic influences start to appear (36%), and the role of the common environment decreases (47%). After the age of 18, genes explain individual differences in sports participation (85%), and the common environmental factors no longer contribute.
The report concluded that environmental factors shared by family members determine sports participation in young adolescence but cease to be of importance in adulthood when individual differences in sports participation are due to genetic variation. These conclusions may hold some water with all athletes in all sports in the sense that continued participation is, for many, dependent on 'success' that can be driven, in part at least, by genetic factors as participants reach adulthood.
Staying with genes we should be truly amazed that there is now a non-invasive test that can tell us if an individual is likely to be good at a particular sport! The test, based on a simple cheek swab, provides information regarding the level of fast-twitch muscle fibres and therefore an indication as to whether the individual is likely to be more suited for speed and power sports or endurance sports or somewhere in the middle. The test does not discriminate good athletes from bad athletes but is designed to assist athletes in identifying the type of events, distances or sports in which success is more likely. For a fee that is affordable by most and using a test that does not involve having a section of muscle removed for biopsy, like it or not, the capability to gain this information appears to now exist.
Intelligent event selection through the use of genetics seems to have arrived as a real option to speed us on our way. Unfortunately, the taking of banned performance-enhancing substances to speed us on our way seems as though it will never go away. A paper reporting on a survey of Olympic athletes from cycling, athletics, rowing, and sailing revealed ongoing ignorance. Over 90% of responders had received a doping educational update in the last six months, and most agreed with the statement "I have received the information I need to avoid getting into trouble with the doping laws".
Despite this, more than half of responders agreed with the statements "I should receive reminders more often" and "The authorities should do more to educate sportspeople". Also, four people admitted to taking a banned substance by accident. Forty-one (55%) reported taking supplements. The report concluded that there is a need to alter the educational process, particularly with contingency planning for minor illness. The use of Internet-based resources for up to date information about banned substances needs to be promoted, and access to the Internet improved. The educational needs of team doctors with doping laws need to be assessed.
An interesting paper reviews the value of coaching feedback in a specific event situation. Based on the comparison of elite and sub-elite sprinters and their block starts the paper supplies a great deal of data on reaction times, power outputs etc. during the response/drive phases and identifies some key differences between elite and sub-elite athletes. The paper goes on to examine the outcome of coaching feedback to the sub-elite aimed at increasing focus on the key kinetic elements. After six weeks of intervention, there was no measurable improvement in sub-elite athlete performance in the chosen parameters. This should not be interpreted as meaning that feedback does not work rather than some forms of feedback without specific supporting training development may be unfruitful.
A further paper based on a study of power athletes (sprinters) looked at the question as to whether or not hydration status can affect sprinting performance. It is well understood that hydration is an important factor in endurance and various claims have been made regarding power performance, e.g. either a similar detrimental effect to endurance due to cardiovascular strain, heat storage and metabolism or an enhancing effect due to loss of body mass positively affecting power to weight. The results, based on measurement of 50m, 200m and 400m sprints as well as vertical jump performance in normal states of hydration and after taking a diuretic and being dehydrated showed no significant differences between the two conditions despite participant losing over 2% of body mass due to the diuretic. Since there appears to be no evidence to support claims of improved performance by losing weight through the use of diuretics, the well-documented health benefits of maintaining levels of hydration seem to override here.
Often, especially when a new skill or element of skill is to be introduced, an athlete is asked to identify their 'strong' leg (or arm). Though the demands of some events may be for a 'strong' limb and an element of unilateral (one-sided) development may be apparent, most events (and indeed daily activities) demand bilateral development and a natural balance of strength is developed. A recent paper tested the unilateral leg squat strength of 42 healthy individuals and found that there was no difference between left and right leg strength even though each individual had a preferred or dominant leg for whatever reason. 'Dominant' leg or limb is, therefore, a more accurate term to adopt when seeking to introduce a skill.
As is well documented another factor that can have a major influence on skill acquisition is fatigue. An interesting study looked at the controlled fatiguing of muscle through electro-stimulation and seeking to identify how fatigue manifests itself. Interestingly, though the most obvious effect was based on central nervous system function (i.e. the whole centrally driven nerve impulse for the action), there was a specific and highly evident fatigue issue with type II fast-twitch fibres resulting from peripheral (or local) neuromuscular propagation failure. This supports the need for central neural training and specific training at the local level.
Previously, I reviewed papers on chronic lower back pain. A further paper, based on the treatment of athletes with a history of this condition, has now come to light. It provides further significant clinical evidence to support the view that a specific mobilization-based intervention utilizing an icing/stretching routine significantly improves mobility and reduces pain.
Moving on to muscle stiffness and soreness arising specifically from eccentric conditioning exercise, a further paper shows a clear advantage to performing specific stretches to hasten recovery and reduce the sensation of these two symptoms when performed during warm-up in sessions after the eccentric session. Stretching, in this case, serves to reduce passive muscle tension caused by muscle damage during the eccentric exercise. Stretching at the start of a training session is supported in these circumstances. Staying with eccentric activity a further study found that this form of exercise when performed at maximal effort could affect both central and peripheral fatigue during sustained maximal voluntary contractions several days later. Eccentric training can be very beneficial to an athlete, but the timing of it with other activities in a particular competition, for example, and the recovery processes need to be carefully considered.
The impact of strength development was studied focusing on elbow flexors to examine differences between individuals as well as between men and women. Almost 600 individuals took part in the study and the findings, after a 12-week program, were that both men and women exhibit a wide range of responses to resistance training with some subjects showing little to no gain, and others showing profound changes, increasing the size by over 10cm and doubling their strength. Men had only a slight advantage in relative size gains compared with women, whereas women outpaced men in relative gains in strength. This provides a big pointer for female athletes - gaining strength can be relatively easy (and is not necessarily associated with getting bigger!)
For many endurance athletes, the very thought of developing muscular strength is quite alien. A detailed study reviews the various forms of strength training and their relative benefits to endurance athletes. The best way to entice you the reader to find out more is to offer an extract from the conclusions section:
"Addition of explosive resistance and high-intensity interval training to a generally low-intensity training program will produce substantial gains in performance"
Another more specific paper looks at the timing of strength and endurance sessions and reports that, circuit training immediately after individualised endurance training in the same session produced greater improvement in the 4 km time trial and aerobic capacity than the opposite order or each of the training programs performed separately. This is enlightening stuff for all coaches!
And finally, two papers looked at hydration and electrolyte levels with cramping in endurance athletes. In the first based on a study of Ironman Triathletes no relationship could be found between body mass or per cent body mass loss during the race and cramping. Though sodium levels were lower in athletes experiencing cramping, they were still within the normal range found in all competitors. No other measured parameters differed including glucose levels, haemoglobin concentration or haematocrit. Surface electromyography revealed higher levels of activity in cramping muscles, as might be expected, relating to the increased neuromuscular activity.
The second paper concluded that consumption of a carbohydrate-electrolyte beverage before and during exercise in a hot environment may delay the onset of cramp but that neither dehydration nor electrolyte loss is the sole causes of cramping since, primarily, 69% of those who did suffer cramps were hydrated and supplemented with electrolytes.
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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 of experience as a 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 of experience in scientific research and publishing.
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