The effect of sleep deprivation and exercise load on isokinetic leg strength and endurance.

Isokinetic leg strength and fatigue were measured in 24 male U.S. Marine Corps volunteers in a simulated sleep loss and unusually heavy work scenario. Knee extension and flexion peak torque (PT) were measured at three isokinetic speeds (1.57, 2.62 and 3.66 rad.s-1) followed by 45 consecutive maximal reciprocal contractions at 3.14 rad.s-1 to measure fatigue index (FI). All subjects were retested 2 days later following 30-h sleep deprivation (SD). The exercise group (n = 12) spent 25 1-h sessions performing computer tasks, filling out questionnaires and walked 1.61 km with a 50% gross body mass pack load, during each of the 25 sessions. The control group (n = 12) did likewise but did not exercise. Repeated measures ANOVA indicated that flexion PT at 1.57 rad.s-1 decreases (P < 0.013) after SD. Exercise did not affect FI but did decrease PT. It was concluded that carrying a 50% load produces decrements in PT for both extension and flexion but more so for flexion. SD affected PT but had no effect on FI.

Comparison of body composition and somatotype of trained female triathletes.

The body composition and somatotype of 16 trained female triathletes aged 18.8-32.8 years were measured. All of the subjects were engaged in a competitive training programme and participated in the same triathlon. Anthropometric variables included height, mass, selected diameters, girths and skinfolds, and a Heath-Carter anthropometric somatotype. Body composition was determined by hydrostatic weighing procedures and skinfold patterns. Comparisons were made with Olympic swimmers and runners. The triathletes had a mean body mass of 55.2 kg and a mean height of 162.1 cm. When compared to swimmers, the triathletes were somewhat shorter and significantly (P less than 0.005) older. On most other measures, including a balanced mesomorph somatotype of 3.1-4.3-2.6, they were similar to swimmers. This group of triathletes were generally heavier, less lean, more mesomorphic and less ectomorphic than elite runners. Reported body densities from other studies indicated little difference between the triathletes and other groups. Skinfold patterns were similar in shape for all groups, but the runners had smaller values, at all sites, than either swimmers or triathletes. Because of lack of information on cyclists, adequate comparisons were not possible. Regression analysis indicated that training parameters were more important than anthropometric measures in the prediction of performance. It was concluded that this group of triathletes were closer, with respect to both body composition and somatotype, to swimmers than to runners.