This study investigated the effects of isokinetic concentric training on isokinetic concentric and eccentric torque outputs. Sixteen female subjects (mean age in years ± SE = 21 ± 1) were randomly assigned to either a training or a control group. Concentric and eccentric torques of the right knee extensors were assessed at 1.05rad·s-1 using a KinCom isokinetic dynamometer system. Each test consisted of a set of four maximal concentric and four maximal eccentric contractions of the knee extensors. The peak and average torques for each contraction were calculated using the computer software supplied by the KinCom manufacturer. On a separate day, after abstaining from heavy exercise for at least 12 hours, a single corr-sectional image of the thigh at midfemur was obtained using computer tomography (CT) scanning. From this image, cross-sectional area of the quadriceps femoris group was calculated using the computer software associated with the General Electric 9800 CT Scanning System. Training group subjects trained three days weekly for six weeks on a Cybex II+ isokinetic dynamometer, completing five sets of ten maximal effort knee extensions at an angular velocity of 1.05rad·s-1. Each set of exercise was separated by two minutes of self-selected recovery. Torque outputs were monitored daily to ensure that adequate recovery was provided between sets of exercise, and to document changes is strength as the program progressed. Significant (p <.01) increases in peak and average concentric torque (11% and 12%, respectively), peak and average eccentric torque (18% and 21%, respectively), and muscle cross-sectional area (3.2%) were observed for training group subjects. A 6% decrease in peak concentric torque was the only significant (p < .05) change observed for the controls. Body weight did not change for either group during the study. These data suggest that under isokinetic conditions concentric training results in significant improvements in both concentric and eccentric torque outputs. This result was evident when considering either peak or average torque during a single contraction. Therefore, application of an exclusive specificity principle to contraction type in resistance training may not be appropriate. The results of this study add to the evidence that resistance training effects may not be as specific to the training mode as has been thought.
|Number of pages||5|
|Journal||Archives of Physical Medicine and Rehabilitation|
|Publication status||Published - Jan 1 1990|
- Muscle contraction
ASJC Scopus subject areas
- Physical Therapy, Sports Therapy and Rehabilitation