For shoulder muscle prevention, we investigated individual shoulder muscle performance and fatigue patterns in various external conditions, including three different % maximum voluntary contractions, six shoulder angles and 60-s durations of exertion. The rating of perceived exertion was also measured for comparison. The upper trapezius (UT), middle deltoid (MD), pectoralis major (PM), latissimus dorsi (LD) and serratus anterior (SA) were selected for assessment. Normalized median power frequency electromyograms were calculated for quantitative fatigue evaluation in ten participants. UT muscle was severely fatigued by extreme flexion angle rather than weight. MD muscle was the most rapidly fatigued after 15 s duration. SA muscle was more fatigued at 0° than 30° adduction. LD and PM muscle fatigue were mostly due to external workload. This muscle specific outcome could help practitioners to design an intervention program targeting particular shoulder injury.

为了预防肩部肌肉，我们研究了各种外部条件下的个别肩部肌肉性能和疲劳模式，包括三种不同的最大自愿收缩百分比，六个肩角和60秒钟的运动时间。还测量了感知的劳累等级，以进行比较。选择上斜方肌（UT），中三角肌（MD），大胸大肌（PM），背阔肌（LD）和前锯肌（SA）进行评估。计算归一化的中频工频肌电图以定量评估十名参与者。极限屈曲角而不是重量使UT肌肉严重疲劳。在15 s的持续时间后，MD肌肉疲劳最快。SA肌肉在0°时比30°内收时更疲劳。LD和PM肌肉疲劳主要归因于外部工作量。