Abstract

Isokinetic plantar flexion peak torque (PT), contractional work (CW), and integrated electromyographic activity (iEMG) were analyzed in a group of untrained females and a group of female elite orienteers. Similar levels of PT, CW, and iEMG were observed in both groups during single maximum maneuvers. During repetitive (299) maximum plantar flexions, the untrained females showed a steeper and more pronounced decline in CW during the first 50 contractions than the orienteers. After this fatique phase, all subjects could maintain a steady-state level of CW throughout the test. This level CW was significantly (20) higher in the orienteers than in the untrained females. The iEMGs of the gastrocnemii and soleus muscle decreased to significantly (10) lower levels in the untrained woman than in the orienteers. For both groups, the soleus muscle showed a significantly higher steady-state level of iEMG (10) than mm. gastrocnemii. In the untrained group, CW/iEMG of m. triceps surae decreased to a plateau level significantly lower than in the orienteerers who could virtually maintain the initial CW/iEMG throughout the test. The differences observed could be explained by adaptations to performed endurance training in the orienteers. Verf.-Referat