EFFECTS OF DETRAINING FOLLOWING SHORT-TERM RESISTANCE TRAINING ON ECCENTRIC AND CONCENTRIC MUSCLE STRENGTH

Healthy males were examined before and after 12 weeks of accommodated resistance training (three week-1) and after 12 weeks of detraining. Training consisted of four to five sets of six coupled maximum voluntary bilateral concentric and eccentric (Grp ECCON; n = 10) or 12 concentric (Grp CON; n = 8) quadriceps muscle actions. Concentric and eccentric peak torque at various constant angular velocities and three repetition maximum half-squat and vertical jump height were measured. Grp ECCON showed greater (P < 0.05) overall increase in peak torque after training and detraining than Grp CON. Thus, concentric peak torque (0.52 rad s-1) increased more (P < 0.05) over the experimental period in Grp ECCON and increases in eccentric peak torque were preserved in Grp ECCON only. Increases in peak torque in response to training were greater (P < 0.05) at 0.52 than at 2.62 rad s-1. Alterations in the torque-velocity patterns induced by training remained after detraining in Grp ECCON but not in Grp CON. The retained increases (P < 0.05) in half-squat were 12 and 18 % in Grps CON and ECCON, respectively. Neither group showed increased vertical jump height after detraining. This study showed greater preservation of concentric and eccentric peak torque after detraining following coupled concentric and eccentric than concentric resistance training. Only the former regime induced a change in the shape of torque-velocity curves that was manifest after detraining. These results suggest that the performance of eccentric muscle actions is critical to optimize increases in muscular strength in response to heavy resistance training, because it probably induce greater and more long-lived neural adaptations than the performance of concentric actions.