What the experts say
Nigel Hetherington reviews the latest research material relating to coaching, exercise physiology and athletic development.
A recent study investigated the effect of the speed with which an athlete moves the bar while bench-pressing, on the relationship between loading and the number of repetitions. Thirteen healthy men age around 21 regularly involved in weight training and with a 1RM in the region of 95-105kg took part. Subjects performed bench presses on a Smith machine at 5 different loadings between 40-80% 1RM, repeated for four different speeds of lift conditions (slow, medium, fast and ballistic i.e. maximum velocity), randomly assigned over 5 experimental sessions after a 1RM test. The speed of lift significantly changed the relationship between loading (%1RM) and the number of reps performed, with faster lifts producing a higher number of repetitions. A significant interaction between loading and speed meant that speed had a much greater effect on repetitions at lower loadings. The practical applications of this study are that the loading (%1RM) will not be consistent unless the speed of the lift is controlled during training.
A paper compared the rate of force development and the peak force exerted between isometric and dynamic mid-thigh clean pulls with subjects standing on a force plate. Though there was no relationship between the rates of force development in either case as the loading increased there was evidence that the peak force correlation improved between isometric and dynamic lifts with loading. The main observation with an impact on assessment was that isometric peak force and dynamic peak rate of force development were strongly related to vertical jump performance. In other words athletes who possess greater isometric maximum strength and dynamic explosive strength tend to be able to jump higher. One observation to make in general here is that isometric strength training, though absolutely proven to be of benefit in increasing strength, muscle bulk and levels of muscle recruitment is still largely underused as part of strength conditioning programs.
Swimmers were studied with respect to the impact of assisted and resisted training utilizing elastic tubes to develop over-strength or over-speed workouts. 100m front crawl swimming performance was investigated in a population of 37 competition level swimmers aged between 14 and 21 years. In the over-strength group swimming velocity and stroke rate increased over 3-weeks while stroke length remained unchanged. In the over-speed group stroke rate increased but stroke length decreased with no overall change in swim velocity. Though both approaches were superior to traditional training programs the over-strength 'resisted' program had a larger impact on muscle strength, swimming performance and stroke technique than the over-speed program.
Complex training continues to be used widely by performance athletes particularly to maximize the strength training benefits within the anaerobic energy systems. A study examined the effect of varying the intra-complex rest period between back squats (5RM) and countermovement jumps between 30 seconds and 6 minutes on a group of 18 men and women. The study found that flight time of the jumps was reduced at both 30 seconds and 6-minutes relative to that at 2 and 4-minutes and that only men improved after 4-minutes rest relative to the performance at 2-minutes. The study went on to examine ground reaction forces and flight times on an individual basis and found that all subjects differed and required a specific rest interval to allow them to perform maximally during the counter-movement jump phase of the complex. Clearly the observation here is that complex training can benefit or inhibit countermovement jump performance depending on the rest interval. The determination of the optimal intra-complex rest interval for each individual may be necessary in the practical setting to maximize the training benefit.
A recent study looked at the effect on post-session blood lactate levels of including an intra-set rest into a bench press workout without increasing the overall volume of rest. In other words performing fewer repetitions per set but performing more sets with the same overall volume of rest. Nine male subjects performed bench presses at a controlled level of force generation at the 6RM level. Blood lactate was determined before, immediately after and 5, 15 and 30 minutes after exercise. It was observed that manipulating the rest period, by increasing the frequency but decreasing the length of each rest period, did not significantly influence the movement associated with resistance training, but did have an effect on the post-exercise blood lactate response when the load, rest duration, and training volume were equated.
This finding may be of practical significance if fatigue is important in strength development or conversely if power training requires minimal fatigue. In the latter case this would be specifically important for athletes who are not highly trained weightlifters where fatigue can more readily lead to loss of technique leading to the possibility of increased injury.
It was also observed that increasing the frequency of the rest period enabled the subjects to perform a greater number of repetitions, resulting in significantly greater blood lactate accumulation. The question to ask yourself right now is, when planning a resistance training session, 'Why do I use a 10-repetition base?' The science seems to indicate no sound basis at all. I guess it's an easy number to remember!
A recent paper starts from the premise that an insight regarding the fluctuations in neuromuscular function among athletes during a taper is lacking and reports on changes in maximal mechanical power (Pmax), velocity at power maximum (V), and swim performance (ms-1) that occur during the taper. Using an arm ergometer measurement was made during the week prior to the initiation of the taper (high volume, HV), during the 2- to 3-week period of the taper, and during the week of peak competition (peak) in 24 male competitive swimmers. Subjects were divided into groups that tapered to peak performance for two different championship competitions.
One group increased Pmax by 10.2% and swim performance by 4.4%. The other increased Pmax by 11.6% and swim performance by 4.7%. Pmax displayed a biphasic increase with approximately 50, 5, and 45% of the total increase occurring during the first, second, and third weeks of the taper, respectively. The biphasic response was the most common response among individual swimmers. Swimming performance was significantly correlated to both power and torque. In summary, maximal arm power measured by ergometry increased largely during the first and third weeks after the training volume was tapered for peak performance in elite swimmers. This may be a factor worth considering in terms of the timing of the competition within the taper period and the design of the taper. Moreover, does this biphasic response over a three week taper period relate to the different recovery modes following intensive training, i.e. acute session fatigue and general muscular recovery (usually of the order of days) and neuromuscular adaptation / chronic fatigue which might take of the order of 10-14 days?
A study compared the effect of dynamic warm up (DWU) with static-stretching warm up (SWU) on power and agility. Subjects aged 18-24 years performed one of the two warm up routines (DWU or SWU) or performed no warm up (NWU) on 3 consecutive days with the process lasting 10-minutes in each case. After 1-2 minutes of recovery, subjects performed 3 tests of power or agility i.e. T-shuttle run, underhand medicine ball throw for distance and a 5-step jump. Repeated measures revealed better performance scores after the DWU for the three performance tests relative to SWU and NWU. There were no significant differences between the SWU and NWU for the medicine ball throw and the T-shuttle run, but the SWU was associated with better scores on the 5-step jump. The authors concluded that because the results of this study indicate a relative performance enhancement with the DWU, the utility of warm up routines that use static stretching as a stand-alone activity should be reassessed. It would be interesting to see this experiment repeated following a general warm-up process in all cases since this may be more analogous to many sports situations.
A very elegant study examined the relative role of energy systems in two ostensibly similar training tests in female hockey players. The activities compared were the Interval Shuttle Sprint Test (ISST - 10 shuttle sprints of 20m starting every 20s) and the Interval Shuttle Run Test (ISRT - 20m continuous shuttle sprints for 30s with a 15s increasing speed walk recovery. Anaerobic (Wingate Test) and aerobic tests (VO2max cycle test) were performed on participants. It was concluded that for the ISST, anaerobic energetic pathways contribute mainly to energy supply for peak sprint time, while aerobic energetic pathways also contribute to energy supply for total sprint time. Energy during the ISRT is supplied mainly by the aerobic energy system. Depending on the aspect of physical performance a coach wants to determine if the ISST or ISRT can be used. It is also important to note that the format of these tests is not unlike many basic training session programs often employed by coaches, particularly in the 'general conditioning phase'. Care should be taken to ensure that the training being applied matches the needs of the athlete and the objectives of the program.
The effect of dehydration on the skills of young male basketball players was studied along with the impact of hydration maintenance with a 6% carbohydrate drink. The study found that deterioration in basketball skill performance accompanied 2% dehydration in skilled 12- to 15-yr-old basketball players. Additionally, hydration maintenance with a 6% carbohydrate electrolyte solution significantly improved shooting performance and on-court sprinting relative to hydration maintenance with water alone.
Whey protein supplementation and its effects on body composition, muscular strength, muscular endurance, and anaerobic capacity during 10 weeks of resistance training by 36 resistance-trained males were studied. Three groups of supplements were randomly assigned - 48gd-1 carbohydrate placebo, 40gd-1 of whey protein + 8gd-1 of casein (WC), or 40gd-1 of whey protein + 3gd-1 branched-chain amino acids + 5gd-1 L-glutamine. At 0, 5, and 10 weeks, subjects were tested for body composition, 1 repetition maximum (1RM) bench and leg press, 80% 1RM maximal repetitions to fatigue for bench press and leg press. WC experienced the greatest increases in lean mass and fat-free mass. Significant increases in 1RM bench press and leg press were observed in all groups after 10 weeks. In this study, the combination of whey and casein protein promoted the greatest increases in fat-free mass after 10 weeks of heavy resistance training. Athletes, coaches, and nutritionists can use these findings to increase fat-free mass and to improve body composition during resistance training.
The amount of ATP stored in the muscle available for immediate use is limited, and once used, must be resynthesized in the muscle. Ribose, a naturally occurring pentose sugar, helps resynthesize ATP for use in muscles. There have been claims that ribose supplements increase ATP levels and improve performance. Other studies have provided mixed results on the effectiveness of ribose as an ergogenic aid at high doses. None of these studies have compared the impact of the recommended dose of ribose on athletes and non-athletes under exercise conditions that are most conducive for effectiveness. A study evaluated the effectiveness of ribose as an ergogenic aid at the dose recommended for supplements currently on the market during an exercise trial to maximize its efficacy. 11 male subjects performed 2 trials 1 week apart. Each trial consisted of three 30-second Wingate tests with a 2-minute recovery between each test. Trials were counterbalanced, with 1 trial being performed with 625 mg of ribose and the other with a placebo. Peak power, mean power, and percent decrease in power were recorded during each Wingate test. There were no significant differences between ribose and the placebo. These results suggest that ribose had no effect on performance when taken orally, at the dose suggested by the distributor.
Finally, this month we look at a report that seeks to identify the smallest worthwhile enhancement in the Olympic-distance triathlon with view to applying this to test situations to monitor progress. Data was taken from 103 athletes in up to nine competitions over a 19 month period. The findings were as follows:
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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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