From the Rehabilitation Unit, Kyoto University Hospital, Kyoto, Japan (JM, YY); Department of Orthopedic Surgery, Kyoto University, Kyoto, Japan (RA, SK, SN, SM); Take Physical Conditioning Gym, Kyoto, Japan (AM, SH); and Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan (NI).
Am J Phys Med Rehabil. 2022 Jun 1;101(6):540-544. doi: 10.1097/PHM.0000000000001860. Epub 2021 Aug 4.
Patients with shoulder disorders show altered periscapular muscle activity (e.g., decreased serratus anterior and increased upper trapezius activities). We herein devised a novel method for strengthening serratus anterior without excessive upper trapezius activation, named squeezing ball exercise in which patients squeezed a ball between both elbows with maximum voluntary isometric contraction in the horizontal adduction direction with the arms elevated at a 45-degree angle. The present study aimed to investigate whether the squeezing ball exercise could produce high muscle activity in the serratus anterior in patients with frozen shoulder and subacromial impingement syndrome before the rehabilitation intervention.
This is a proof-of-concept study. Serratus anterior and upper trapezius activities during squeezing ball exercise were evaluated using electromyography in 16 patients with frozen shoulders and subacromial impingement syndrome. Electromyography signals were normalized using maximal voluntary isometric contraction, and the muscle balance ratios (upper trapezius/serratus anterior) were calculated.
The average serratus anterior and upper trapezius activity was 69.9% ± 30.8% and 10.2% ± 6.3% maximal voluntary isometric contraction during the squeezing ball exercise, respectively, whereas the upper trapezius-serratus anterior ratio of the affected side was 0.15 ± 0.07.
The high serratus anterior activation and low upper trapezius-serratus anterior ratio during squeezing ball exercise could be attributed to the limb position where shortened serratus anterior exerts itself without painful subacromial impingement. Squeezing ball exercise could be a novel rehabilitation tool for patients with frozen shoulders and subacromial impingement syndrome.
肩部疾病患者的肩胛带肌活动会发生改变（例如，前锯肌活动减少，上斜方肌活动增加）。我们在此设计了一种新的方法，通过在水平内收方向上用最大随意等长收缩力挤压球，在手臂抬高 45 度角的情况下，在肘部之间挤压球，以增强前锯肌而不会过度激活上斜方肌，这种方法称为挤压球练习。本研究旨在探讨挤压球练习是否可以在肩部冻结和肩峰下撞击综合征患者进行康复干预之前，在前锯肌中产生较高的肌肉活动。
这是一项概念验证研究。在 16 例肩部冻结和肩峰下撞击综合征患者中，使用肌电图评估挤压球练习时的前锯肌和上斜方肌活动。肌电图信号使用最大随意等长收缩进行归一化，并计算肌肉平衡比（上斜方肌/前锯肌）。
挤压球练习时，前锯肌和上斜方肌的平均活动分别为最大随意等长收缩的 69.9%±30.8%和 10.2%±6.3%，而患侧的上斜方肌-前锯肌比值为 0.15±0.07。
挤压球练习时前锯肌高激活和上斜方肌-前锯肌比值低可能归因于缩短的前锯肌在没有疼痛的肩峰下撞击的情况下发挥作用的肢体位置。挤压球练习可能是肩部冻结和肩峰下撞击综合征患者的一种新的康复工具。
