Ankle position during strength training does influence isokinetic knee extensor and flexor strength gains

Abstract

Background: Recently, the training effect of the multijoint system was more effective than isolated joint exercise in restoring function in patients with patellofemoral dysfunction. Researchers have investigated whether differences in ankle position can facilitate or inhibit knee activity on peak torque and total work. Some researchers reported that maximum isometric electromyographic activity levels of the quadriceps during active ankle dorsiflexion or plantarflexion were greater than those performed with the ankle in a neutral position. However, all of these studies assessed knee strength during the isokinetic or isometric mode for testing alone and did not examine the effect of ankle position on isokinetic knee extensor andflexor strength gains during knee isokinetic strengthening training. Purpose: The purpose of this study was to investigate the influence of two different active ankle positions such as plantarflexion and dorsiflexion during the isokinetic training on strengthening knee flexors and extensors. Methods: A volunteer sample of 22 healthy adults was randomized to ankle dorsiflexion (AD) and ankle plantarflexion (AP) training groups. Subjects were trained isokinetically in knee extension and flexion under two actively fixed, contracted ankle conditions (dorsiflexion or plantarflexion) four times a week for three weeks. Results: The AD group had significant improvements in the PT (peak torque) and the TW (total work) of knee extensors at 60◦/sec and the PT and the TW of knee flexors at both 60◦/sec and 180◦/sec. Significant gains in the PT and the TW of knee extensors at 180◦/sec and the PT and the TW of knee flexors at both speeds were also observed in the AP group. The AD group demonstrated 29% greater post-training gain than the AP group in the PT and TW for knee extensors at 60◦/sec (p< 0.05). The PT and TW of knee flexors at 60◦/sec in the AD group also revealed significantly greater gains by 45%and59%, respectively, than those ofAPgroup (p< 0.05). Conclusion(s): These results suggest that active ankle dorsiflexion in a knee strength training programmay bemore efficient to increase knee extensor and knee flexor strength than a plantarflexed position. Implications:Knee isokinetic strength trainingwith ankle positionwill be important clue to provide basic data and information to clinicians and patientswith knee injury like anterior cruciate ligament injury or patellofemoral dysfunction.