An examination of strength and concentric work ratios during variable range of motion training

Clark, RA, Bryant, AL, and Humphries, B. An examination of strength and concentric work ratios during variable range of motion training. J Strength Cond Res 22(5): 1716-1719, 2008-Variable range of motion (ROM) training consists of partial ROM resistance training with the countermovement being performed at a different phase of the movement for each set. In this study, we assessed the effect of this method of training on peak force, load lifted, and concentric work performed. Six male subjects with resistance training backgrounds (age 20.2 ± 1.3 years, height 179.4 ± 4.6 cm, weight 89.6 ± 9.9 kg, 6-repetition maximum [6RM] bench press 92.5 ± 14.3 kg) participated in this study. Testing consisted of 6RM bench press strength tests during full (FULL), three quarter (3/4), one half (1/2), and one quarter (1/4) ROM from full elbow extension bench press performed on a Smith machine. The 6RM load, peak force (PF), and concentric work (W) performed during each ROM was examined using a one-way analysis of variance performed at an a level of p < 0.05. The 6RM load increased significantly as the ROM was decreased for all tests (FULL = 92.5 ± 14.3 kg, 3/4 = 102.1± 14.3 kg, 1/2 = 123.3 ± 23.6 kg, 1/4 = 160.9 ± 26.2 kg). PF during each test was significantly higher during the 1/4 (1924.8 ± 557.9 N) and 1/2 (1859.4 ± 317.1N) ROM from full elbow extension bench press when compared with the 3/4(1242.2 ± 254.6 N) and FULL (1200.5 ± 252.5 N) ROM exercise. Although higher force levels were evident, the restriction in barbell displacement resulted in a subsequent reduction in W as the lifting ROM was reduced. These results suggest that variable ROM resistance training results in increased force production as the ROM diminishes. © 2008 National Strength and Conditioning Association