Note: [*] Staff Physical Therapist, St. Francis Hospital Center, Indianapolis,IN.
Note: [**] Address reprint requests to Mark F. Reinking, MS, PT, ATC at St. Francis Hospital Center, 1600 Albany St., Beech Grove, IN 46107.
Abstract: This study was devised to assess the different effects of concentric and eccentric actions on the tibialis anterior in a short-term strengthening regimen. It was hypothesized that any changes that may emerge in a pre- and posttest strength assessment would be from primarily neurologic alterations. Forty-four subjects were randomly divided into a control (n = 15), eccentric training (n = 14), and concentric training (n = 15) groups. The training groups performed eight training sessions over a 3-week period, allowing at least 1 day of rest between sessions. The training employed a modified daily adjusted progressive resistive exercise technique that used Thera-Band (Hygenic Corp., Akron, OH) as the resistance mode. Pre- and posttest data were collected via a Biodex dynamometer (Shirley, NY) of the ankle dorsiflexion pattern (30 and 90 deg/sec). No significant changes were observed in peak torque, and only the eccentrically trained group exhibited significant change of the total work performed of an eccentric pattern at 30 deg/sec. No significant changes were seen at 90 deg/sec. The results show a significant increase in total work at 30 deg/sec without an increase in peak torque. An alteration of the shape of the generated curve was seen with a “smoothing” occurring during the posttest. This finding is supportive of an enhancement of neuromuscular integration and an enhancement of neural function in the recruitment of muscle fibers during eccentric activation.
