Kinematic And Kinetic Analysis Of The Influence Of Chains On The Execution Of The Clean

Abstract

Chain training, a technique where chains are hung from the ends of conventional barbells, is rapidly increasing in popularity in strength training facilities nationally. Advocates contend that the use of chains assists in the development of explosive power, increased core stabilization, and enhanced motor control and balance. Yet, empirical evidence to substantiate these claims is lacking. PURPOSE To investigate the influence of chains on the execution of the clean. METHODS Three female and four male competitive weightlifters who have used chains in their training participated in the study. Each lifter employed his or her individual warm-up protocol prior to performing one repetition under the following conditions: (1) 75% of the individual's 1 repetition maximum (RM) using only the conventional bar and weights, (2) 80% of the individual's 1 RM, 75% of which was accounted for by the conventional bar and weights with the remaining 5% accounted for by the addition of chains, (3) 80% of the individual's 1 RM using only the conventional bar and weights, (4) 85% of the individual's 1 RM, 80% conventional bar and weights, 5% chains and (5) 85% of the individual's RM using only the conventional bar and weights. Each trial was completed by all lifters before moving to the next higher percentage load ensuring ample rest between lifts. During each trial, lifters positioned their right foot on an AMTI force platform which collected ground reaction forces at a rate of 1000 HZ. In addition, all trials were videotaped, capturing the subject's right side in the sagittal plane at 60 HZ. A reflective marker was placed on the end of the bar facing the camera. Kinematic data were digitized and analyzed using the PEAK Motus 4.3 motion analysis system. Separate paired t-tests were used to examine maximum vertical displacement of the bar, maximum bar velocity, and the vertical ground reaction forces (Fz) for the first pull, unweighting, and second pull phases of each lift. RESULTS For the 80% conventional bar and weights only lift, significantly greater vertical displacement of the bar occurred (t = 0.038, p<.05). For the chain lift at 80%, force plate data revealed significantly greater ground reaction forces during both the unweighting (t = .005, p<.05) and 2nd pull phases (t = .035, p<.05). No significant differences were found for the 85% lift (p>0.05). CONCLUSION Results suggest that chains have minimal influence on the execution of the clean in trained competitive weightlifters. Future longitudinal research with chains must be conducted to assess the efficacy and transfer specificity of chain training.