Aerobic fitness associated with repeated-sprint ability in women.

2004 NOV 4 - (NewsRx.com & NewsRx.net) -- Muscle buffer capacity and aerobic fitness are associated with repeated-sprint ability in women.

"In addition to a high aerobic fitness, the ability to buffer hydrogen ions (H+) may also be important for repeated-sprint ability (RSA). We therefore investigated the relationship between muscle buffer capacity (betam[subscript]in vivo and betam[subscript]in vitro) and RSA. Thirty-four untrained females [mean (SD): age 19 (1) years, maximum oxygen uptake (VO[subscript]2peak) 42.3 (7.1) mL/kg per min] completed a graded exercise test (GXT), followed by a RSA cycle test (five six-second sprints, every 30 seconds). Capillary blood was sampled during the GXT and before and after the RSA test to determine blood pH (pH(b)) and lactate concentration ([La-][subscript]b)," scientists in Australia report.

"Muscle biopsies were taken before (n=34) and after (n=23) the RSA test to determine muscle lactate concentration ([La-][subscript]i), hydrogen ion concentration ([H+][subscript]i) pH[subscript]i, betam[subscript]in vivo and betam[subscript]in vitro," stated David Bishop and colleagues at the University of Western Australia. "There were significant correlations between work decrement (%) and betam[subscript]in vivo (r=-0.72, p

"There were also no significant correlations between total work (J/kg) during the RSA test and betam[subscript]in vitro, betam[subscript]in vivo, or changes in [La-][subscript]i, pH[subscript]i, [La-][subscript]b, or pH[subscript]b," reported Bishop and his collaborators. "There were significant correlations between total work ...