King Grub
2016-02-04, 12:43
The purpose of this study was to determine the effects of deadlift chain variable resistance on surface electromyography (EMG) of the gluteus maximus, erector spinae, and vastus lateralis muscles, ground reaction forces (GRFs), and rate of force development (RFD). Thirteen resistance trained men (24.0 ± 2.1 y, 179.3 ± 4.8 cm, 87.0 ± 10.6 kg) volunteered for the study. On day one, subjects performed 1 repetition maximum (1RM) testing of the deadlift exercise. On day two, subjects performed one set of three repetitions with a load of 85% 1RM with (CH) and without chains (NC). The order of the CH and NC conditions was randomly determined for each subject. For the CH condition, the chains accounted for approximately 20% (19.9 ± 0.6%) of the 85% 1RM load, matched at the top of the lift. Surface EMG was recorded to differentiate muscle activity between conditions (CH, NC), range of motion (ROM; bottom, top) and phase (concentric, eccentric). Peak GRFs and RFD were measured using a force plate. EMG results revealed that for the gluteus maximus there was significantly greater EMG activity during the NC condition versus the CH condition. For the erector spinae, EMG activity was greater at the bottom than the top ROM (p < 0.05). Force plate results revealed that deadlifting at 85% 1RM with an accommodating chain resistance of approximately 20% results in a reduction in GRFs (p < 0.05) and no change in RFD (p > 0.05). Collectively, these results suggest that the use of chain resistance during deadlifting can alter muscle activation and force characteristics of the lift.
J Strength Cond Res. 2016 Jan 29. An Electromyographic and Force Plate Analysis of the Deadlift Performed With and Without Chains.
J Strength Cond Res. 2016 Jan 29. An Electromyographic and Force Plate Analysis of the Deadlift Performed With and Without Chains.