Employing an arched back posture during the bench press exercise is increasingly popular. Vertical displacement of the barbell is commonly believed to be the key difference influencing strength performance between an arched and flat back bench press technique. However, comparisons between these back postures using a free weight barbell are lacking. Directly comparing performance between each posture is confounded by many variables such as proficiency and fatigue. This investigation aimed to investigate whether changing back posture alone can influence barbell kinematics, to indirectly assess potential performance differences. Twenty males performed one repetition of the bench press exercise using either an arched or flat back posture, at 25%, 50% and 75% of their one repetition maximum, in a repeated measures study design. Statistical significance was considered at p < 0.05. Changing back posture alone, reduced vertical displacement (approximately 11% average difference across all load conditions) and barbell to glenohumeral joint moment arm (approximately 20% difference) in the arched posture compared to the flat posture. These changes occurred without any specific cueing of the barbell motion and may increase the potential for lifting higher loads and decrease cumulative joint exposure. Additional cueing and training may be required to maximize the mechanical advantage available with each back posture. The arched posture appears to have an increased potential for further improvements in vertical displacement and moment arm through specific cueing. Future comparisons should consider if each back posture’s potential mechanical advantage has been maximized when assessing differences between techniques.

在卧推锻炼中采用弓形的背部姿势越来越受欢迎。通常认为，杠铃的垂直位移是影响弓形和卧推式卧推技术之间强度性能的关键差异。但是，缺乏使用自由重量杠铃的这些背部姿势之间的比较。直接比较每个姿势之间的性能会受到许多变量的干扰，例如熟练程度和疲劳程度。这项研究旨在调查仅改变背部姿势是否会影响杠铃运动学，从而间接评估潜在的性能差异。在重复测量研究设计中，二十名男性使用弓形或向后平躺姿势进行了一次卧推练习的重复，其重复次数最多达到一次重复的25％，50％和75％。统计学显着性被认为在p <0.05。相对于平坦姿势，仅改变背部姿势即可，减少弓形姿势的垂直位移（在所有负载条件下平均差异约11％）和杠铃至盂肱关节力矩臂（差异约20％）。这些变化的发生没有杠铃运动的任何特定提示，并且可能增加举起更高负荷的可能性并减少累积的关节暴露。可能需要额外的提示和训练，以最大程度地利用每种后仰姿势提供的机械优势。拱形的姿势似乎具有通过特定提示进一步改善垂直位移和力矩臂的潜力。