The Optimum Range of Motion of Elbow to Strengthen the Rotator Cuff Muscles from Pronated Grip Pull-Ups

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