isokinetic strength of knee extensors: A randomized clinical trial

Objective: The purposes of this study were (1) to investigate and (2) to compare effects of isometric exercises and electrical stimulation on isokinetic strength for healthy quadriceps femoris muscle.Methodology: Twenty healthy volunteers (range, 20-25; mean age, 20.9 +/- 1.1 yr) participated in the study. All participants were divided into two groups (Group I and Group II). Each group consisted of 10 subjects. While Group I received electrical stimulation with Russian current, Group II trained with maximal volunteer isometric exercises (10s contraction and 50s relaxing periods with 10 repetitions) for three days per week for six weeks. Before and after the training program, each subject was evaluated using the following tests; anthropometrical measurements, fixed weight repetition, step-up, decline squat, single leg hop, and isokinetic assessments (peak torque, work per repetition, initial peak torque, fatigue index, total work done, %BW).Results: After a 6-week training program, significant differences in terms of physical functioning and isokinetic parameters in the two groups were found (p 0.05). Quadriceps femoris hypertrophy was only found in electrical stimulation group (p < 0.05).Conclusion: The results obtained from this study show that the two strengthening techniques just used in the study can be used to improve muscle strength, performance and isokinetic parameters in healthy quadriceps femoris muscle (p < 0.05). But, there is no superiority on each other. In conclusion, these results indicate that electrical stimulation and maximal volunteer isometric exercises can be used to increase isokinetic strength as an alternative for isokinetic dynamometer in clinical setting