Abstract:
The most of rotator cuff (RC) muscle injuries occurr due to the lack of strength in the
RC muscles. The pull-up is one of the exercises that can be used to strengthen the RC.
Thus, the study provides a specific range from the pronated grip pull-up that in RC
muscles strengthening. The baseball players (n=4) who mostly engage with overhead
movement and completed up to ten repetitions of pull-ups were used in this study. The
wireless electrodes with Delsys Trigno electromyography (EMG) sensors were used to
conduct the surface EMG test and 2D video recording (sagittal plane) were conducted
simultaneously as data gathering methods. The videos were analysed using the human
movement analysis software (Kinovea 0.9.5) and the Lab Chart Reader software 8.1.22
was utilized for the EMG signal analysis. According to the results of the EMG test for
the infraspinatus muscle (one of the RC muscles), the elbow angle from 940 to 1350 at
the eccentric phase has shown the activation. Therefore, it is recommended to adapt
the elbow angle from 940 to 1350 while performing pronated grip pull-ups in order to
strengthen the RC muscles of baseball players. Although, the conclusion of this study is
disputable since the sample is not generalizable. Thereby, more researches are required
to identify all the RC muscles activation in pull-ups motion with players of other sports
