The Effect of a Strength and Speed Weight Training Program on Unilateral and Bilateral Concentric Contraction Strength and Bilateral Deficit in Elbow Flexion

Document Type : Research Paper


1 Kharazmi University

2 Islamic Azad University (Tehran)


The force exerted by a single limb during a maximal bilateral contraction is found to be less than the force associated with a maximal unilateral contraction. This phenomenon is called bilateral deficit. Therefore, the aim of this study was to determine the effect of a strength and speed weight training program on unilateral and bilateral concentric contraction strength and deficit in elbow flexion. For this purpose, 50 non-athlete males (mean age 21.57+1.91 yr, weight 72.22+14.31 kg and height 175.61+3.31 cm) voluntarily participated in this study. Subjects (n=50) were randomly assigned to a control group (n=10) or divided into four weight training groups (n=10) who performed arm curl exercise as: 1) unilateral strength, 2) bilateral strength, 3) unilateral speed or 4) bilateral speed training. Training was two sessions/week for 8 weeks and an intensity of 80-100% of (1RM) for strength group with three sets (one repetition) and four sets (ten repetitions) with an intensity of 50-80% of 1RM for speed group. Control subjects attended sessions but performed no exercise. Maximal concentric strength of right elbow flexion (RL1RM), left elbow (LL1RM) and bilateral elbow (BL1RM) was performed before and after training. Data were analysed using inferential statistics, MANOVA and SLD post hoc tests at p<0.05. The results showed no significant difference between unilateral and bilateral strength training, also between bilateral and unilateral speed training in elbow flexion muscle strength for right, left and both hands. Both strength training groups outperformed the two groups of speed training; also, four experimental groups outperformed the control group. Bilateral training groups
outperformed the unilateral training groups and control group in the facilitation of elbow flexion bilateral deficit. Therefore, in order to prevent bilateral deficit in bilateral sports, bilateral strength and speed weight training is suggested.