Lawrence Michael A, Leib Daniel J, Ostrowski Stephanie J, Carlson Lara A
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.
J Strength Cond Res. 2017 May;31(5):1206-1211. doi: 10.1519/JSC.0000000000001610.
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.
劳伦斯、马萨诸塞州、莱布、DJ、奥斯特罗夫斯基、SJ以及卡尔森、LA。不稳定卧推杠铃路径与肌肉激活的非线性分析。《力量与体能研究杂志》31(5): 1206 - 1211, 2017年——不稳定阻力训练通常用于提高稳定肌在负荷下维持关节完整性的能力。本研究的目的是使用非线性分析方法，研究不稳定负荷（由柔性杠铃和弹性带悬挂的负荷提供）对卧推时杠铃路径、主要肌肉组织和稳定肌肉组织的影响。15名有阻力训练经验的男性（年龄24.2±2.7岁，体重84.1±12.0千克，身高1.77±0.05米，举重经验9.9±3.4年，卧推1次最大重复量（1RM）为107.5±25.9千克）自愿参与本研究。受试者分别使用标准杠铃和柔性“地震”杠铃，在稳定（总负荷为1RM的75%）和不稳定（总负荷为1RM的60%）条件下各进行2组，每组5次重复的卧推。使用表面肌电图来检测主要发力肌（胸大肌、三角肌前束和肱三头肌）以及杠铃稳定肌肉组织（背阔肌、三角肌中束和后束、肱二头肌和斜方肌上束）的肌肉活动。在不稳定条件下，杠铃的移动方式更多，并且在内外侧和前后方向上更难以预测。然而，使用不稳定杠铃时，所有肌肉的肌肉激活模式受到的约束更大。这些发现表明，不稳定条件更具挑战性，但受试者通过以更稳定的模式收缩肌肉或在整个运动过程中“保持紧绷”来控制不稳定性。
