ORIGINAL ARTICLE Argyris G. Toubekis Æ Helen T. Douda Savvas P. Tokmakidis Influence of different rest intervals during active or passive recovery on repeated sprint swimming performance Accepted: 19 September 2004 / Published online: 20 November 2004 Ó Springer-Verlag 2004 Abstract The purpose of this study was to investigate the effect of active or passive recovery after two different rest intervals on performance during repeated bouts of maximal swimming exercise. Sixteen swimmers (eight males and eight females) performed four trials in a counterbalanced order. Eight repetitions of 25-m sprints (8·25 m), with a rest interval of 45 or 120 s, followed by a 50-m sprint test 6 min later, were performed in each trial. The 45 or 120-s interval was either active (A45 and A120) or passive (P45 and P120). The intensity of the active recovery corresponded to 60% of the individual best 100-m velocity. Performance time was recorded using an official competition timing system. The first 25- m sprint was comparable across trials (P>0.05), but performance was decreased after the second sprint dur- ing active compared to passive recovery, irrespective of the interval duration (P<0.05). The 50-m sprint time was 2.4% better in the P120 and A120 compared to the A45 and P45 trials (P<0.05). After completing the 8·25 m, blood lactate was decreased with active recov- ery when the interval period was 120 s (P120 vs A120, P<0.05). Blood lactate concentration at the start as well as 5 min after the 50-m sprint was lower in the A120 and A45 compared to the P120 and P45 trials respectively (P<0.05). Plasma glycerol was not different between trials (P>0.05), whereas plasma ammonia was higher in the A45 compared to the P120 trial (P<0.05). The in- terval period separating short-duration sprints may therefore alter performance when subsequent maximum exertion is applied. For sustained sprinting ability, pas- sive recovery is advised during repeated swimming sprints of short duration. Keywords Active recovery Æ Sprint swimming Æ Interval duration Æ Performance Introduction It has been suggested that when active recovery is ap- plied between repeated bouts, it may facilitate perfor- mance more than when applying passive rest (Maglischo 2003). When active recovery is applied during the rest interval between short-duration sprints in cycling (i.e. 6– 30 s), performance is better maintained compared to passive recovery (Signorile et al. 1993; Ahmaidi et al. 1996; Bogdanis et al. 1996b). This may be attributed to increased muscle blood flow (Bangsbo et al. 1994), which in turn may facilitate oxygen supply to the cell for a faster phosphocreatine (PCr) resynthesis. During successive bouts of sprint exercise, a short- duration interval period leads to incomplete resynthesis of PCr (Gaitanos et al. 1993; Bogdanis et al. 1996a, 1998). At the same time, anaerobic glycolysis results in high levels of muscle lactate associated with hydrogen ions. Lactate can no longer be considered the cause of fatigue (Gladden 2004). However, intramuscular meta- bolic byproducts, such as inorganic phosphate as well as hydrogen ions, may act to impair muscle function (Hermansen 1981). Even though aerobic ATP contri- bution increases to compensate for the reduced rate of ATP provided by anaerobic sources (Bogdanis et al. 1996a), it does not prevent the significant reduction in power output and velocity which occurs during repeated short-duration cycling, swimming or running (Balsom et al. 1992a; Gaitanos et al. 1993; Peyrebrune et al.1998). Studies conducted with swimmers examined the application of active recovery after long-duration (about 2 min) swimming exercise and after long resting periods (i.e. 14 min, Felix et al. 1997; or 3 min, McMurray 1969). However, it is possible that changes in duration and intensity of the exercise as well as duration of the resting interval alter energy contribution. It has been A. G. Toubekis Æ H. T. Douda Æ S. P. Tokmakidis (&) Department of Physical Education and Sport Science, Democritus University of Thrace, 69100 Komotini , Greece E-mail: stokmaki@phyed.duth.gr Tel.: +30-531-39649 Fax: +30-531-39683 Eur J Appl Physiol (2005) 93: 694–700 DOI 10.1007/s00421-004-1244-9