What the experts say
Nigel Hetherington reviews the latest research material relating to coaching, exercise physiology and athletic development.
The first paper reviewed this month examines skill development in senior sportspeople. We often hear about the importance of laying down a foundation of activity-based around technique during the 'skill hungry years' around 10-12. In contrast, we often hear the phrase 'You cannot teach an old dog new tricks' about older players. The study's purpose was to determine whether multidimensional perceptual-cognitive skills training, including situational awareness, anticipation, and decision making, improves on-court performance in older adults compared with a physical training program, including stroke and footwork development. Twenty-seven senior tennis players were randomly assigned to one of three groups: perceptual-cognitive skills training, technique-footwork training, or no training. Results indicated that participants receiving perceptual-cognitive skills training had significantly faster response speeds, a higher percentage of accurate responses, and a higher percentage of performance decision making in post-test match situations. Findings provide clear evidence that perceptual-cognitive skills can be trained in aged individuals. The old dog just got a new trick!
In a study the fascicle (muscle bundle) length of the human medial gastrocnemius (MG) muscle was monitored to evaluate possible input from the short-latency stretch reflex (<55ms, SLR) during the stance phase of running and to examine its timing at various running speeds. Eight subjects ran at 2.0, 3.5, 5.0, and 6.5 m/s. During ground contact, the sudden MG fascicle stretch occurred during the early contact at all running speeds. This was followed by the fascicle shortening. The timing of fascicle stretches depended on running speed and type of foot contact. In slower speed conditions (2.0, 3.5, 5 m/s), the MG fascicle stretch and the corresponding SLR activities occurred during the middle of the braking phase. In fast-speed running (6.5 m/s), however, the MG fascicle stretch occurred later compared with the lower speed. The corresponding SLR activities occurred significantly later at the end of the braking phase. In addition to the clear demonstration of the different timings of SLR in MG during ground contact of running, the results imply that the role of the MG SLR during the stance phase of running can be different between fast- and slow-speed running conditions. These factors should be taken into account in planning appropriate running activities.
Imagine you could test muscular endurance without getting tired! A recent paper highlights exactly how to do that - well nearly - using repetitive magnetic stimulation the muscle still fatigues but at least the subject does not have to run, cycle or row for 2 hours!
A follow-up paper specifically examined the effect of repetitive magnetic stimulation (rMS) of the intramuscular branches of the femoral nerve to establish if it is used to induce and quantify quadriceps endurance. The authors compared in vivo contractile properties of the quadriceps muscle with the fibre-type composition and oxidative enzyme capacity. Force generation and the surface electromyogram were measured throughout. Quadriceps twitch force, elicited by supramaximal magnetic stimulation of the femoral nerve, was measured before and after the protocol. Quadriceps muscle biopsies were analysed for oxidative (citrate synthase, CS) and glycolytic (phosphofructokinase, PFK) enzyme activity and myosin heavy chain isoform protein expression. They concluded that quadriceps endurance assessment using rMS is feasible.
A paper further examined the understanding that a recent bout of high-intensity exercise can alter the balance of aerobic and anaerobic energy provision during subsequent exercise above the lactate threshold. The idea here is that through the careful coupling of activities within a programme, the energy systems can be 'primed' ready to increase the opportunity for targeting the development of one system over another. However, it remains uncertain whether such 'priming' influences the tolerable duration of subsequent exercise through changes in the parameters of the aerobic function (e.g. lactic threshold, maximum oxygen uptake (O2max)] and/or the hyperbolic power-duration relationship. The authors studied six men performing cycle ergometry to the limit of tolerance with a series of key measurements being recorded. All tests were subsequently repeated with a preceding 6-min supra-CP priming bout and an intervening 2-min recovery. The results suggest that, following supra-CP priming, there is either a reduced depleted energy resource or a residual fatigue-metabolite level that leads to the tolerable limit before this resource is fully depleted.
In recent years Caffeine was removed from the WADA list of banned substances - recent papers might serve to bring this decision back under the spotlight. Caffeine (CAF) increases blood pressure both at rest and during exercise. The effect of acute CAF ingestion combined with intense resistance training on cardiovascular function is, however, unknown. A study examined changes in cardiovascular function after completion of fatiguing bench-press and leg-press exercise after CAF or placebo ingestion. Twenty-two resistance-trained men ingested CAF (6 mg/kg) or placebo one-hour pre-exercise. They refrained from CAF intake and strenuous exercise 48 and 24 h pretrial, respectively. Heart rate and blood pressure were measured pre-exercise. After a standardized warm-up, 1-repetition-maximum (1-RM) on the barbell bench press and leg press was tested. When it had been determined, a load equivalent to 60% of 1-RM was placed on the bar, and the subject completed repetitions to failure. Measurements of heart rate and blood pressure were immediately completed, and mean arterial pressure was calculated. Results showed significant increases in heart rate (+ 10 beats/min) and systolic blood pressure (+ 8-10 mmHg) with acute CAF ingestion versus placebo. No change in diastolic blood pressure across time or treatment was shown. To prevent elevated blood pressure and potential enhanced risk of heart disease, the authors concluded that CAF intake should be monitored in at-risk men who participate in resistance training.
A study determined the effects of Red Bull energy drink on Wingate cycle performance and muscle endurance. Healthy young adults (11 men, 4 women, average age 21 years) participated in a study in which they were randomized to supplement with Red Bull (2 mg/kg body mass of caffeine) or an isoenergetic, isovolumetric, non-caffeinated placebo, separated by seven days. Muscle endurance (bench press) was assessed by the maximum number of repetitions over three sets (separated by 1-min rest intervals) at an intensity corresponding to 70% of baseline 1-repetition maximum. Three 30-s Wingate cycling tests with two minutes recovery between tests were used to assess peak and average power output. Red Bull energy drink significantly increased total bench-press repetitions over 3 sets (Red Bull = 34 ± 9 vs. placebo = 32 ± 8) but had no effect on Wingate peak or average power (Red Bull = 701 ± 124 W vs. placebo = 700 ± 132 W, Red Bull = 479 ± 74 W vs. placebo = 471 ± 74 W, respectively). Red Bull energy drink significantly increased upper body muscle endurance but did not affect anaerobic peak or average power during repeated Wingate cycling tests in young healthy adults.
A further study assessed the perceptions, knowledge, and experiences of caffeine use by athletes competing at the 2005 Ironman Triathlon World Championships. Questionnaires were distributed to 140 athletes (105 men and 35 women, average age 40 years) representing 16 countries during pre-race registration. A large proportion (73%) of these endurance athletes believed that caffeine is ergogenic to their endurance performance, and 84% believe it improves their concentration. The most commonly reported positive caffeine experiences related to the in-competition use of cola drinks (65%) and caffeinated gels (24%). The athletes' ability to accurately quantify the caffeine content of common food items was limited. The most popular sources of caffeine information were self-experimentation (16%), fellow athletes (15%), magazines (13%), and journal articles (12%). Over half the athletes (53%) could not identify the amount of caffeine required to improve their triathlon performance. The mean suggested doses were 3.8 (±±3) mg/kg body weight. Few side effects associated with taking caffeine during exercise were reported.
A fascinating study had three objectives: 1) to explore athletes' preferences for informational and emotional content within pre-game speeches according to types of sporting situations, 2) to explore coaches' and athletes' perceptions of preferred informational and emotional content within pre-game speeches, and 3) to explore potential gender differences. Participants were 208 collegiate varsity athletes (121 male, 87 female). Athletes and coaches completed measures assessing preferences for pre-game speech content and demographic variables. Results indicated that athletes preferred differing amounts of information and emotion according to the situation and athletes' and coaches' perceptions of needed emotion within pre-game speeches differed as well. Gender differences were also found; female athletes placed higher values on the amount of information than their male counterparts. No gender differences were found in the amount of emotional content.
A research report explored factors that may influence whether coaches adopt desired behaviours. The research was conducted with a census survey of Canadian coaches who had completed all or part of their National Coaching Certification Program Competition-Introduction coach education. The results indicate that several factors may influence desired coaching behaviour. The factors include competitive experience as an athlete, hours of coaching per week, and whether the coaches are coaching an individual or team sports. The results provide empirical evidence that factors beyond coach education influence whether coaches engage in sound coaching practice. So, as we say, obtaining a coaching license through a formal education course is one thing, but.
A study explored relationships between pre-competition anxiety and in-competition coping in swimmers. Thirty-nine male swimmers with international competitive experience participated in the study (average age 19 years and competitive experience 9 years). Participants completed a short measure of anxiety intensity and direction before the start of their event and a coping questionnaire after the completion of their event. Correlation analysis showed that the intensity of cognitive anxiety had low to moderate negative correlations with approach coping strategies, and low to moderate positive relationships with avoidance coping strategies. Furthermore, somatic anxiety intensity had low to moderate positive relationships with avoidance strategies. Finally, analysis of variance revealed that swimmers perceiving their anxiety states as facilitative reported more approach and less avoidance coping strategies than swimmers perceiving their anxiety states as debilitative. Following previous evidence from the sports anxiety literature, the results suggest that facilitative perceptions of anxiety symptoms relate to more adaptive cognitive and behavioural outcomes. Therefore, coaches should emphasize not only the regulation of anxiety intensity but also the way swimmers perceive anxiety symptoms.
-It's okay to feel nervous, now go out there and channel it' might be the advice to give!?
A systematic research publication review set out to identify randomised controlled trials and controlled intervention studies that evaluated the effectiveness of preventive injury strategies in adolescent sport and to conclude the strength of the evidence. The review concluded that injury prevention strategies that focus on preseason conditioning, functional training, education, balance and sport-specific skills, which should be continued throughout the sporting season, are effective. Those coaches who miss this key message in a 'periodised' approach to training should review their planning strategy to ensure these key elements are retained with the training programme at all times if injury avoidance is to be maximised
Heavy exercise can be associated with an increased risk of upper respiratory tract infections. Strenuous exercise also causes gastrointestinal (GI) symptoms. In previous studies, probiotics have reduced respiratory tract infections and GI symptoms in general populations, including children, adults, and the elderly. These questions have not been studied in athletes before. A study investigated probiotics' effect on the number of healthy days, respiratory infections, and GI-symptom episodes in marathon runners in the summer. One hundred forty-one marathon runners were recruited for an intervention study during which they received Lactobacillus rhamnosus GG (LGG) or placebo for a 3-month training period. At the end of the training period, the subjects took part in a marathon race, after which they were followed up for two weeks. The mean number of healthy days was 79.0 in the LGG group and 73.4 in the placebo group. There were no differences in the number of respiratory infections or GI-symptom episodes. The duration of GI-symptom episodes in the LGG group was 2.9 vs 4.3 d in the placebo group during the training period and 1.0 vs 2.3 d, respectively, during the 2 wk after the marathon. The authors concluded that LGG had no effect on the incidence of respiratory infections or GI-symptom episodes in marathon runners, but it shortened the duration of GI-symptom episodes.
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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, and 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.