title: A mechanical comparison of linear and double-looped hung supplemental heavy chain resistance to the back squat: a case study.
abstract: A relatively new and scarcely researched technique to increase strength is the use of supplemental heavy chain resistance (SHCR) in conjunction with plate weights to provide variable resistance to free weight exercises. The purpose of this case study was to determine the actual resistance being provided by a double-looped versus a linear hung SHCR to the back squat exercise. The linear technique simply hangs the chain directly from the bar, whereas the double-looped technique uses a smaller chain to adjust the height of the looped chain. In both techniques, as the squat descends, chain weight is unloaded onto the floor, and as the squat ascends, chain weight is progressively loaded back as resistance. One experienced and trained male weight lifter (age = 33 yr; height = 1.83 m; weight = 111.4 kg) served as the subject. Plate weight was set at 84.1 kg, approximately 50% of the subject's 1 repetition maximum. The SHCR was affixed to load cells, sampling at a frequency of 500 Hz, which were affixed to the Olympic bar. Data were collected as the subject completed the back squat under the following conditions: double-looped 1 chain (9.6 kg), double-looped 2 chains (19.2 kg), linear 1 chain, and linear 2 chains. The double-looped SHCR resulted in a 78-89% unloading of the chain weight at the bottom of the squat, whereas the linear hanging SHCR resulted in only a 36-42% unloading. The double-looped technique provided nearly 2 times the variable resistance at the top of the squat compared with the linear hanging technique, showing that attention must be given to the technique used to hang SHCR.
authors.affiliation: Department of Physical Therapy and Health Science, Bradley University, Peoria, Illinois, USA. kurtn@bradley.edu
authors.forename: Kurt R
authors.initials: KR
authors.lastname: Neelly
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Terry
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Morris
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D055070:Resistance Training / Q000295:instrumentation / Q000379:methods*; D016474:Weight-Bearing / Q000502:physiology*