The purpose of this study was to examine power output and fatigue from power-time curves of cycle ergometer and isokinetic dynamometer tests. Fifteen physically active female university athletes performed a 45 s cycle ergometer test at resistances of 0.075, 0.085, and 0.095 kp/kg bw, as well as a 45 s and a 3 repetition isokinetic flexion and extension test at velocities of 60, 180, and 300$ sp circ$/s. Results revealed that peak power, mean power (W and W/kg), and fatigue (W/kg) were highest at the 0.095 kp/kg bw resistance and lowest at the 0.075 kp/kg bw resistance. Significant differences among the three cycle ergometer conditions existed for peak power, mean power, and fatigue. Peak power and mean power (W and W/kg) were highest at 300$ sp circ$/s and lowest at 60$ sp circ$/s. Results revealed significant differences among the isokinetic dynamometer conditions for peak and mean power. Mean power output (W) was significantly correlated (range of r = 0.56 to r = 0.74) for the cycle ergometer and the isokinetic dynamometer test conditions.

The intent of this thesis was to study the effects of caffeine ingestion on substrate utilization and muscle metabolism during exercise, as reflected by endurance time to exhaustion. For this purpose, seven trained cyclists performed work bouts at 80% of maximal oxygen consumption to exhaustion after ingestion of caffeine (CAF trial) end under control (CON trial) conditions.Although the work time to exhaustion was not significantly different between the CAF trial, 91.8 (S.E. ± 7.7) min and the CON trial, 85.2 (S.E. ± 10.5) min, five of he subjected did show an average 18% increase in performance following ingestion of 330 mg caffeine. Since there was no elevation of FFA prior to exercise, it was expected that no muscle glycogen sparing would occur during the first 30', 41.7 (S.E. ± 6.1) mM/kg in the CAF trial and 42.1 (S .E. + 6.6) mM/kg in the CON trial. Serum glycerol concentration was significantly (P< .05) during the CAF trial at 10' and 30'. R values were significantly lower during the CAF trial, .87 (S.E. ± .01) than the CON trial, .91 (S.E. ± .01) at exhaustion. Significantly lower (p<.05) perceived exertion ratings were also observed during the CAF trial. These data suggest a positive effect on endurance exercise performance following caffeine ingestion.

The purpose of this study was to examine the effects of recovery modes and exercise durations on blood lactate concentrations and subsequent performance in cycling tests. Fourteen male subjects completed six randomly assigned experimental protocols with a combination of three durations and two modes of recovery (passive and active cycling at 45% VO$ sb{ rm 2 max}$). Each protocol consisted of eight bouts of cycling at 120% of VO$ sb{ rm 2 max}$ interspersed with five minute recovery periods. Each protocol terminated with a maximal performance task consisting of a 45s all-out cycling test. Results indicated significantly (p $<$ 0.05) higher blood lactate concentrations in the passive and 60s conditions. Mean power outputs measured in the performance task were significantly (p $<$ 0.05) higher in the active recovery conditions compared to passive recovery. Mean power outputs were lower during the 60s conditions. Since the correlation between blood lactate and mean power output was low (r = -0.24), other factors were influencing subsequent performance.

Blood lactate concentration and mean power output were examined over a series of maximal intermittent exercise bouts with varying recovery patterns. Thirteen elite male cyclists completed four randomly assigned experimental conditions. Each exercise/recovery condition consisted of twelve 10 s maximal exercise bouts on a Monark cycle ergometer. Four different recovery patterns (30, 60, 90 and 120 s) followed the repeated 10 s all-out efforts. Results revealed that the mean power output averaged over the 12 trials was 12.7, 13.0, 13.2 and 13.4 W/kg, for the 30, 60, 90 and 120 s conditions, respectively. Blood lactate concentration during exercise were 9.9, 9.2, 6.5 and 6.0 mmol/1, for the 30, 60, 90 and 120 s conditions, respectively. The 30 and 60 s conditions yielded significantly lower mean power output values compared to the 90 and 120 s conditions. Following the repeated maximal 10 s efforts, blood lactate concentration was significantly greater in the 30 and 60 s recovery conditions compared to the 90 and 120 s conditions.

The purpose of this study was to evaluate metabolic, cardiorespiratory, and perceptual responses during recumbent cycle ergometry performed at various seat back angles and different work rates. Healthy college-aged men performed steady-state exercise at two work rates, 100 watts (n=46) and 150 watts (n=26), using five back seat angles, 90, 105, 120, 135, and 150 degrees. The results of this study suggest that recumbent seat back angles of 135 to 150 degrees are associated with lower metabolic and cardiorespiratory stress during rest and submaximal exercise than more upright positions. The reduced stress at these angles is accompanied by lower perceptions of exertion and improved seating comfort. The failure of the base-line correction for resting V0 2 to remove the effect of seat back angle implies that the reduced physiological stress associated with these positions is due to reasons other than attenuated resting metabolic costs. It is concluded that the selection of recumbent seat back angles between 135 and 150 degrees can result in improved efficiency, reduced physiological stress, diminished perceptions of exertion, and increased seating comfort.

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