Studies were conducted to assess the relationship between buffer capacity (b) and repeated-sprint ability (RSA). Extracellular buffering systems appear important as we have reported significant correlations between RSA and and bblood (r=-0.69). In a follow-up study, 10 females performed a RSA test following the ingestion of either NaHCO3 (0.3 g/kg) or a placebo (NaCl: 0.207 g/kg). Compared with NaCl ingestion, the NaHCO3 trial resulted in a significant improvement in sprints 3, 4 and 5. The significant increase in post-test [La]m and [La]b during the NaHCO3 trial suggests that an increased anaerobic energy contribution is one mechanism by which NaHCO3 ingestion improved RSA. Intracellular buffering systems also appear important as we have reported significant correlations between RSA and bmuscle (r=-0.68). Furthermore, we have shown that despite being matched for total work, and producing similar increases in VO2max (10 - 12%), interval training, when compared to continuous training, produces significantly greater improvement in bmuscle and RSA (4.5%). While these results suggest that beta;muscle may be an important attribute for RSA, we have recently observed significant improvements in RSA despite a significant decrease in bmuscle following very high- intensity training. Thus, further research is required to investigate the relationship between RSA and both intracellular and extracellular buffer capacity