Effects of a 4-week eccentric training program on the repeated bout effect in young active women.

The aim of this study was to analyze the responses of women to the repeated bout effect (RBE) and to a short eccentric training program. Twenty-four young females were randomly assigned to a training group (TG, n = 14) or a control group (CG, n = 10). They performed two identical acute eccentric bouts (120 repetitions at 70% of 1RM) in a leg-press device in an 8 weeks interval. TG followed a 4-week-eccentric-training program between the bouts. Maximal isometric contraction, range of motion, peak power and quadriceps muscle soreness were compared between and within groups before and after the two acute eccentric bouts. TG and CG presented significant losses of isometric strength and peak power, and an increment in soreness after the first bout. Isometric strength and peak power were recovered faster in CG after the second bout (p < 0.05) compared with TG, which showed a similar recovery of these parameters after the second bout compared with the first one. A decrease in soreness and a faster recovery of range of motion were found in TG (p < 0.05) following the second bout compared with the first one, but not in CG. Data indicate that a 4-week eccentric training program may prevent the RBE over those adaptations related with muscle damage (e.g. strength loss), but it may increase RBE impact on inflammatory processes (e.g. soreness). Key pointsAn acute bout of eccentric exercise induces losses of strength, peak power and range of motion, and increases muscle soreness in young active women.When the acute eccentric bout is repeated by young women, the losses of strength and power are smaller, indicating less muscle damage. However, muscle pain and range of motion do not present any difference with the results obtained after the first bout, which would indicate that the repeated bout effect does not affect inflammatory response after acute eccentric exercise.Four weeks of eccentric training is enough to increase maximal isometric strength, but not dynamic strength (1RM) or peak power. Furthermore, this training seems to prevent those adaptations provided by the repeated bout effect related with muscle damage. On the other hand, the eccentric training seems to be a positive tool to decrease muscle soreness, and thus the inflammatory response, associated to a repeated acute eccentric bout.