Abstract
Objective: To determine the effect of lower extremity muscle strength training in healthy young adults on improvement of stability and performance.
Methodology: In this study 37 volunteers with mean age of 21.35±0.94 years were included and were randomly divided into 3 groups. Each group was trained for 3 days a week for 4 weeks. First group (group I) was trained with Russian stimulation to the knee extensors muscles, second group (group II) was trained by whole-body vibration (WBV) and third group (group III) was a control group and had no training. Balance was assessed with Portable Kinesthetic Ability Trainer (SPORTKAT 550). Quadriceps muscle strength was evaluated with Hand-Held dynamometer and lower extremity performance was measured with step-up test.
Results: Muscle strength (p>0.05), step-up test (p<0.05) and static balance increased (p<0.05) in group I and group II muscle strength (p>0.05) and step-up test (p<0.05) increase, while the decrease in static balance (p<0.05) was found. In III group, muscle strength (p<0.05) and static balance (p<0.05) increased, step up to the test (p> 0.05) decreased. After training muscle strength, static balance, and step up test results of participants in group I and II did not increase significantly compared to group III.
Conclusion: Although 4 weeks Russian stimulation and WBV methods improved the muscle strength in groups I and II compared to Group III, lower extremity endurance and the balance, there was no advantage relative to each other.

Key words: Whole-body Vibration, Russian stimulation, balance, performance