The effects of a plyometric training program on the latency time of the quadriceps femoris and gastrocnemius short-latency responses

Authors

D H Potach; D Katsavelis; G M Karst; R W Latin; N Stergiou

Abstract

Aim

The purpose of this study was to determine if a plyometric training program can affect the latency time of the quadriceps femoris and gastrocnemius short-latency responses (SLRs) of the stretch reflex.

Methods

Sixteen healthy subjects (12 female and 4 male) were randomly assigned to either a control or a plyometric training group. Maximum vertical jump height (VJ) and SLRs of both quadriceps femoris and gastrocnemius were measured before and after a four week plyometric training program.

Results

Plyometric training significantly increased VJ (mean+/-SEM) by 2.38+/-0.45 cm (P<0.05) and non-significantly decreased the latency time of the quadriceps femoris SLR (mean+/-SEM) 0.363+/-0.404 ms (P>0.05) and gastrocnemius SLR (mean+/-SEM) 0.392+/-0.257 ms (P>0.05). VJ results support the effectiveness of plyometric training for increasing VJ height.

Conclusions

The non-significant changes in the latency time of the quadriceps femoris and gastrocnemius SLRs seen in the training group suggest that performance improvements following a four-week plyometric training program are not mediated by changes in the latency time of the short-latency stretch reflex.

Link

Potach DH, Katsavelis D, Karst GM, Latin RW, Stergiou N. The effects of a plyometric training program on the latency time of the quadriceps femoris and gastrocnemius short-latency responses. J Sports Med Phys Fitness. 2009;49(1):35-43.