Comparison of muscle buffer capacity and repeated-sprint ability of untrained, endurance-trained and team-sport athletes

We measured the muscle buffer capacity (beta m) and repeated- sprint ability ( RSA) of young females, who were either team- sport athletes ( n= 7), endurance trained ( n= 6) or untrained but physically active ( n= 8). All subjects performed a graded exercise test to determine V O2peak followed 2 days later by a cycle test of RSA ( 5 x 6 s, every 30 s). Resting muscle samples ( Vastus lateralis) were taken to determine bm. The team- sport group had a significantly higher bm than either the endurance- trained or the untrained groups ( 181 +/- 27 vs. 148 +/- 11 vs. 122 +/- 32 mu mol H+ g dm (-1) pH (-1) respectively; P < 0.05). The team- sport group also completed significantly more relative total work ( 299 +/- 27 vs. 263 +/- 31 vs. 223 +/- 21 J kg (-1), respectively; P < 0.05) and absolute total work ( 18.2 +/- 1.6 vs. 14.6 +/- 2.4 vs. 13.0 +/- 1.9 kJ, respectively; P < 0.05) than the endurance-trained or untrained groups during the RSA test. The team- sport group also had a greater post- exercise blood lactate concentration, but not blood pH. There was a signi. cant correlation between beta m and RSA ( r = 0.67; P < 0.05). Our findings show that young females competing in team sports have a larger bm than either endurance-trained or untrained females. This may be the result of the intermittent, high- intensity activity during training and the match play of team- sport athletes. The team- sport athletes also had a greater RSA than either the endurance- trained or untrained subjects. The greater total work by team- sport athletes was predominantly due to a better performance during the early sprints of the repeated- sprint bout.