摘要
Background： Using a cross-sectional design comparison, two overhead press techniques （in-front of the head or behind the head） were compared. The purpose of this study was to determine the impact of behind the head or in-front of the head overhead pressing technique on shoulder range of movement （ROM） and spine posture. The overhead press is commonly prescribed exercise. The two techniques （in-front of the head or behind the head） may influence joint mechanics and therefore require an objective analysis. Methods： Passive shoulder ROM quantified using goniometric measures, dynamic ROM utilised three-dimensional （3D） biomechanical mea- sures （120 Hz） of 33 participants performing overhead pressing in a seated position. The timing and synchronisation of the upper limb shoulder and spine segments were quantified and influence of each technique was investigated. Results： The in-front technique commenced in lordotic position, whilst behind the head technique commenced in kyphotic position. Behind the head technique started with less thoracic extension than in-front condition. The thoracic spine remained extended and moved between 12~ and 15~ regardless of gender or technique. The techniques resulted in a significant difference between genders. Males were able to maintain a flat or normal lumbar lordosis, whereas females tended to kyphotic. Conclusion： Shoulder ROM was within passive ROM for all measures except external rotation for males with the behind the head technique. To avoid possible injury passive ROM should be increased prior to behind the head protocol. Females showed greater spine movements, suggesting trunk strengthening may assist overhead pressing techniques. For participants with normal trunk stability and ideal shoulder ROM, overhead pressing is a safe exercise （for the shoulder and spine） when performed either in-front of or behind the head.
背景:肩上举是一种常用练习,两种技术(头前式和头后式)可能会影响关节结构,因此需做客观分析。本研究旨在通过横向比较研究两种肩上举技术对肩部活动度和脊柱姿态的影响。方法:运用角度测量和三维生物力学测试方法研究33名受试者进行坐姿肩上举练习时肩关节的被动和主动活动幅度。结果:头前举在脊柱前凸的姿势下开始,头后举在脊柱后凸的姿势下开始。与头前举相比,头后举开始时的胸部伸展幅度更小。无论何种性别、何种肩上举技术,胸推均呈伸展状,且动作过程中的角度为12°-15°。两种肩上举技术在性别上表现出显著性差异。男性能保持正常的腰椎前凸,而女性则表现为腰椎后凸。结论:除头后式技术时男性肩关节产生外旋外,其余的肩关节动作幅度都在被动动作幅度之内。为避免可能出现的损伤,在头后式肩上举练习前应增加被动动作幅度。女性显现出更大的脊柱活动度,表明加强躯干力量有助于肩上举动作的完成。对具有正常躯干稳定性和理想肩关节动作幅度的受试者来说,无论头前式还是头后式,推举对于肩部和脊柱都最一种较为安全的练习。
