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Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation.
J Strength Cond Res. 2017 May; 31(5):1206-1211.JS

Abstract

Lawrence, MA, Leib, DJ, Ostrowski, SJ, and Carlson, LA. Nonlinear analysis of an unstable bench press bar path and muscle activation. J Strength Cond Res 31(5): 1206-1211, 2017-Unstable resistance exercises are typically performed to improve the ability of stabilizing muscles to maintain joint integrity under a load. The purpose of this study was to examine the effects of an unstable load (as provided by a flexible barbell and a load suspended by elastic bands) on the bar path, the primary musculature, and stabilizing musculature while bench pressing using nonlinear analyses. Fifteen resistance-trained men (age 24.2 ± 2.7 years, mass 84.1 ± 12.0 kg, height 1.77 ± 0.05 m, 9.9 ± 3.4 years of lifting experience, and bench press 1 repetition maximum (RM) 107.5 ± 25.9 kg) volunteered for this study. Subjects pressed 2 sets of 5 repetitions in both stable (total load 75% 1RM) and unstable (total load 60% 1RM) conditions using a standard barbell and a flexible Earthquake bar, respectively. Surface electromyography was used to detect muscle activity of primary movers (pectoralis major, anterior deltoid, and triceps) and bar stabilizing musculature (latissimus dorsi, middle and posterior deltoid, biceps brachii, and upper trapezius). During the unstable condition, the bar moved in more ways and was less predictable in the mediolateral and anteroposterior directions. However, the muscle activation patterns of all muscles were more constrained with the unstable barbell. These findings suggest that the unstable condition was more challenging to control, but subjects controlled the instability by contracting their muscles in a more stable pattern or "staying tight" throughout the exercise.

Authors+Show Affiliations

1Department of Physical Therapy, University of New England, Portland, Maine; 2Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri; 3Department of Exercise and Sport Performance, University of New England, Portland, Maine; and 4Center for Excellence in the Neurosciences, University of New England, Biddleford, Maine.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27548799

Citation

Lawrence, Michael A., et al. "Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation." Journal of Strength and Conditioning Research, vol. 31, no. 5, 2017, pp. 1206-1211.
Lawrence MA, Leib DJ, Ostrowski SJ, et al. Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation. J Strength Cond Res. 2017;31(5):1206-1211.
Lawrence, M. A., Leib, D. J., Ostrowski, S. J., & Carlson, L. A. (2017). Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation. Journal of Strength and Conditioning Research, 31(5), 1206-1211. https://doi.org/10.1519/JSC.0000000000001610
Lawrence MA, et al. Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation. J Strength Cond Res. 2017;31(5):1206-1211. PubMed PMID: 27548799.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation. AU - Lawrence,Michael A, AU - Leib,Daniel J, AU - Ostrowski,Stephanie J, AU - Carlson,Lara A, PY - 2016/8/23/pubmed PY - 2017/6/16/medline PY - 2016/8/23/entrez SP - 1206 EP - 1211 JF - Journal of strength and conditioning research JO - J Strength Cond Res VL - 31 IS - 5 N2 - Lawrence, MA, Leib, DJ, Ostrowski, SJ, and Carlson, LA. Nonlinear analysis of an unstable bench press bar path and muscle activation. J Strength Cond Res 31(5): 1206-1211, 2017-Unstable resistance exercises are typically performed to improve the ability of stabilizing muscles to maintain joint integrity under a load. The purpose of this study was to examine the effects of an unstable load (as provided by a flexible barbell and a load suspended by elastic bands) on the bar path, the primary musculature, and stabilizing musculature while bench pressing using nonlinear analyses. Fifteen resistance-trained men (age 24.2 ± 2.7 years, mass 84.1 ± 12.0 kg, height 1.77 ± 0.05 m, 9.9 ± 3.4 years of lifting experience, and bench press 1 repetition maximum (RM) 107.5 ± 25.9 kg) volunteered for this study. Subjects pressed 2 sets of 5 repetitions in both stable (total load 75% 1RM) and unstable (total load 60% 1RM) conditions using a standard barbell and a flexible Earthquake bar, respectively. Surface electromyography was used to detect muscle activity of primary movers (pectoralis major, anterior deltoid, and triceps) and bar stabilizing musculature (latissimus dorsi, middle and posterior deltoid, biceps brachii, and upper trapezius). During the unstable condition, the bar moved in more ways and was less predictable in the mediolateral and anteroposterior directions. However, the muscle activation patterns of all muscles were more constrained with the unstable barbell. These findings suggest that the unstable condition was more challenging to control, but subjects controlled the instability by contracting their muscles in a more stable pattern or "staying tight" throughout the exercise. SN - 1533-4287 UR - https://www.unboundmedicine.com/medline/citation/27548799/Nonlinear_Analysis_of_an_Unstable_Bench_Press_Bar_Path_and_Muscle_Activation_ DB - PRIME DP - Unbound Medicine ER -