THE EFFECT OF COMBINED VERSUS ECCENTRIC TRAINING ON MARKERS OF OVERSTRESS298

Abstract

The main purpose of the study was to determine if the eccentric phase of a squat would induce muscle trauma and subsequent performance decrements in IRM comparable to combined concentric-eccentric training. 28 weight trained subjects were assigned to an eccentric (ECC, n=11) or combined (COM, n=9) training group. ECC lowered the weight from a standing to a parallel position. COM performed both phases of the squat. All performed 13 training sessions (10 sets; 1 rep/set, 100% IRM 2min rest between sets). IRM was assessed on a daily basis. Peak isometric and isokinetic forces were assessed before, mid-, and after training. Muscle biopsies to assess glycogen levels and muscle damage, were performed before and after the training. Profile of Mood States (POMS) were completed every 3d. A repeated measures ANOVA (p<.05) revealed no significant group difference in: IRM squat, glycogen depletion, and POMS. There was a significant decrease in isometric force for COM, and a significant increase for ECC. Z-line streaming, indicative of muscle damage, was seen in ECC. Conclusion: similar physiological and psychological responses were observed between the two training groups. Surprisingly, even though damage was evident in ECC, they demonstrated a significant increase in isometric strength, suggesting that muscle trauma might not be a limiting factor in an increase in isometric force.