Muscle activity and forces in different suspension lunge exercises

Abstract

Although there are some researches about lunge exercise and instability conditions (i.e., Bosu, fitball), few researches were found comparing different methods using a suspension device and its load quantification. The purpose of this study was to examine the effect of suspension training and instability surfaces on muscle activity and force production while performing different variations of the lunge exercise. A randomized within-subjects design was used to study the effects of five conditions (traditional, suspension, suspension-Bosu, suspension-Vibro30 or Vibro40) on five different muscles (rectus femoris, biceps femoris, vastus medialis, vastus lateralis and gluteus medius) in physically active male university students (n = 7; age = 25.71± .06 years old). During lunge performance, muscle activation was recorded using surface electromyography (sEMG). Force production was obtained using both Wii Balance Board and a S-Type load cell. Mean peak force and normalized sEMG values were compared across the 5 exercises. Results showed no significant differences in muscle activity between traditional and suspension lunge. However lunges performed with dual instability increased sEMG activity in the analysed muscles in comparison with single instability condition. Furthermore, force output on the strap decrease when instability increase and suspension lunge showed significant differences (p< .05) on forward leg exerted force in comparison with traditional lunge. In conclusion, the results obtained in the present study could be useful for select the optimal lunge progression and the load cell seems to be an adequate tool to quantify the load while performing a suspension exercise.