Effects of exercise intensity on the stretch-shortening cycle function of the lower limbs after cycling / 体力科学

This study aimed to elucidate the effects of exercise intensity on stretch-shortening cycle (SSC) function of the lower limbs after cycling. Ten male triathletes performed a cycling graded test to determine the ventilatory threshold (VT) and two hopping-cycling (30 min of cycling at 90 or 110% VT)-hopping tests. The two hopping-cycling-hopping tests performed in random order. Power output (PO), heart rate (HR) and rate of perceived exertion (RPE) were monitored throughout the 30-min cycling. Blood lactate concentrations (BLa) were measured in order to assess metabolic stress. The SSC function was calculated as the ratio of the jump height to the time spent in contact with the ground (reactive strength index [RSI]). PO, HR and RPE values during cycling at 110%VT was higher than at 90%VT (p < 0.01). BLa value after the cycling at 110%VT was higher than at 90%VT (90%VT: 2.4±1.0 vs. 110%VT: 5.9±2.8 mmol/L, p < 0.01). Regardless of the cycling exercise intensity, the RSI significantly decreased after the cycling exercise (p < 0.01). The RSI remained decreased at 15 min after the cycling exercise (p < 0.05). These results demonstrated that the SSC function decreased after cycling. Exercise intensity during cycling is likely to have no effect on the decrease in SSC function.

A comparison of aerobic capacity in long-distance runners and triathletes with the same level of running performance / 体力科学

The purpose of this study was to clarify the aerobic fitness of triathletes comparing with long-distance runners with the same level of running performance. Thirteen male university endurance athletes were divided into two groups ; long-distance runners and triathletes. The subjects performed maximal and submaximal treadmill running test to assess their maximal oxygen uptake (VO2max) and running economy (RE). The VO2max (ml/kg/min) in triathletes was lower than that in the runners (p = 0.08, d = 1.18). The RE (ml/kg/km) in triathletes was higher than that in the runners (p = 0.05, d = 1.34). This study suggests that the difference of aerobic fitness between two homogeneous groups is caused by running form and the training with preceding exercise.