Single and repeated-sprint protocols result in significant rises in blood and muscle lactate (La-bl and La-m), and significant decreases in muscle pH (pHm) and phosphocreatine (PCr)(1,2). High correlations have been demonstrated between the percentage restoration of power during a second 30-s sprint and the percentage resynthesis of PCr, while neither pHm or La-m recovery were related to the recovery of 30-s sprint performance(1). To date, however, no study has investigated the relationship between the recovery of muscle metabolites and the recovery of repeated-sprint performance. Furthermore, no study has investigated metabolite concentrations at a point when subsequent performance is fully recovered. The aim of the present study was to identify the relationships between performance recovery and the recovery of muscle metabolites, La-bl and oxygen consumption (VO2) following 5 x 6-s repeated-sprint exercise. Nine female soccer players (mean ± SD: age 27 ± 7 y; mass 60.5 ± 5.3 kg; VO2max 50.0 ± 3.9 mL/kg/min) performed two consecutive 5 x 6-s maximal sprint-cycle bouts (B1 and B2) on eight separate occasions. The five sprints within each bout were separated by 24 s of active recovery and the two bouts were separated by passive recovery periods lasting 5 – 14 min. Trials 1 – 6 were used to identify the least time required to recover total work done (Wtot) over a 5 x 6-s bout (time = trec). During trial 7, expired air was collected between B1 and B2(separated by trec). During trial 8, blood samples and v. lateralis muscle biopsies were taken at rest, immediately post B1 and at theindividual trec. Following trec (mean ± SD: 10.7 ± 1.2 min), Wtot recovered to 100 ± 1.05 % (B1: 18575 ± 1792 J, B2: 18579 ± 1861 J; P=0.947).La-bl was higher than at rest both immediately post B1 and after trec (11.6 ± 3.2 and 10.9 ± 4.6 vs 1.0 ± 0.5 mmol/L; P<0.001). pHmdropped during B1 (7.1 ± 0.1 to 6.9 ± 0.1; P<0.01) and recovered to 7.1 ± 0.1 at trec (not different from rest, P>0.1). La-m content was elevated above the resting value post B1 (95.0 ± 54.7 vs 14.4 ± 1.6 mmol/L; P<0.05) and dropped significantly during recovery, remaining higher than the resting value (38.0 ± 16.4 mmol/L; P<0.05). PCr was reduced to 43 ± 22 % of resting content following B1 and despite recovering to 82 ± 13 %, remained lower than baseline PCr content after trec. During recovery from B1, VO2 was unchanged (i.e., hadstabilised) after 3.0 min (P>0.05). Results suggest that the full recovery of La-bl, La-m and PCr is not necessary for the recovery of 5 x 6-ssprint performance in trained, female, team-sport athletes. Instead it may be more important for pHm to have returned to baseline levels and for sufficient PCr resynthesis to have occurred to recover work in a second bout. 1. Bogdanis G., et al. (1995). J Physiol 482(2): 467-480; 2. Bishop D., et al. (2004). Eur J Appl Physiol 92: 540-547. The first author’s position is supported by the EU-funded Interreg IIIa programme.