The effects of a plyometric training program on the latency time of the quadriceps femoris and gastrocnemius short-latency responses.
OBJECTIVE
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.
Potach
D H
DH
Nebraska Biomechanics Core Facility, University of Nebraska at Omaha, Omaha, NE 68182-0216, USA.
Katsavelis
D
D
Karst
G M
GM
Latin
R W
RW
Stergiou
N
N
D000328:Adult; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*; D012026:Reflex, Stretch / Q000502:physiology*; D055815:Young Adult