ABSTRACT
The purpose of this study was to determine the age and habitual physical activity on re-oxygenation time in working muscles following maximal cycling exercise (CycEXmax). Twelve sedentary middle-aged (50±6), 13 sedentary elderly (66±3), 13 active middle-aged (53±5), and 20 active elderly (67±5) were evaluated the half re-oxygenation time (T1/2 reoxy) as an index of oxygen delivery, using near-infrared spectroscopy at the vastus lateralis (VL) and lateral head of the gastrocnemius (LG) after CycEXmax. T1/2 reoxys at VL and LG were significantly greater in the elderly subjects than in the middle-aged subjects in both sedentary and active groups. T1/2 reoxys at VL and LG of the active group were smaller than those of the sedentary group, regardless of age. The results of this study suggest that habitual physical activity may attenuate age-related prolongation in T1/2 reoxy in working muscles although ageing delay T1/2 reoxy in working muscles.
ABSTRACT
The purpose of this study was to investigate the effects of creatine loading on rowing performance in well-trained male competitive rowers (age 19.4±0.2 yr, height 182.2 ± 1.2 cm, weight 76.6±1.1 kg, mean±SE) . Twenty subjects were randomly separated into creatine (n=10) or placebo group (n=10) . Subjects performed simulated 2000 m rowing race and 20 sec maximal rowing on a rowing ergometer, before and after 6 days of creatine (20g of creatine monohydrate plus 4g of lactose per day) or placebo (24g of lactose per day) ingestion, The creatine and placebo were administered in a double-blind research design. Performance time for 2000 m rowing was improved significantly from 407.9±5.3sec to 404.7±5.4sec (p<0.01) in the creatine group, but no significant changes were observed in the placebo group. No significant changes were observed in power output during 20 sec maximal rowing in either groups. These results suggest that creatine loading can enhance performance in simulated 2000 m rowing race in well-trained competitive male rowers but has no beneficial effect on 20 sec maximal rowing.