Richard L. Burse

The assessment of the static component in rhythmic exercise

AbstractA new approach has been devised to assess the “static component” of dynamic exercise. This technique involves the measurement of the isometric endurance of muscles which have just taken part in rhythmic exercise and depends on the repeatability of trained subjects in isometric effort. The premise is that isometric endurance will be inversely related to the static component of the preceding dynamic exercise. The subjects worked on a bicycle ergometer at known fractions of their maximal aerobic capacity (max

Isometric fatigue induced by different levels of rhythmic exercise

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Procedures for the measurement of acute mountain sickness.

). The rate of pedalling was varied from 30 to 90 rpm, so that for a given % max

Operation everest II: neuromuscular performance under conditions of extreme simulated altitude

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Respiratory response and muscle function during isometric handgrip exercise at high altitude.

, the belt tension varied inversely with the speed of cycling. At any one speed of cycling, isometric endurance decreased as the belt tension increased. Following exercise at 30 rpm, the isometric endurance was 25 to 50% lower than that found at the most advantageous speed of cycling for our subjects; at these faster rates of cycling two subjects showed least static component following exercise at 90 rpm while the remaining subject performed best after cycling at 50 rpm.

Influence of posture on isometric fatigue.

SummaryEight healthy male subjects (age range 24–38 year) were asked to exert a fatiguing isometric endurance contraction with their handgrip muscles at 40% of their maximum strength after immersion of their forearms in water at various temperatures ranging from 3–40‡ C. For each subject, isometric endurance was longest after immersion of his forearm in water at a particular characteristic bath temperature; endurance decreased markedly above or below this temperature. The increase in heart rate from the beginning to the end of the fatiguing contractions was the same irrespective of the bath temperature. In contrast, the increase in blood pressure (both systolic and diastolic) throughout the contractions was almost constant for contractions exerted after immersion of the forearm in water at 20–40‡ C, but was reduced progressively for contractions exerted in water below 20‡ C.