Take Home Points

  1. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training.

Rotator cuff diseases are common musculoskeletal issues. There are several causes and symptoms of rotator cuff diseases. It is important to implement treatments appropriate for each case. As one gets older and the rotator cuff weakens or tears, it becomes harder to avoid rotator cuff diseases. There have been a number of studies that have proposed methods to prevent these symptoms through rotator cuff muscle training exercises. Kim (2014) examined individualized resistance training programs for the prevention of rotator cuff disease. Five participants (machine group) performed individualized shoulder internal and external rotation training with a resistance training machine. Another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation power was measured using an isokinetic machine before and after training.

The average power of both shoulder internal and external rotation improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training.
Haptic-based training and dumbbell-based training show common progresses on average power. The differences in average power progress of external rotation between the groups are due to the differences when engaged in exercise using dumbbells as opposed to exercise using haptic-based resistance training (Kim 2014). Each person’s joint angle-torque was examined as shown in and the resistance of the haptic device was based on this measurement. With the control group, the exercise load was chosen by the weight of the dumbbell and the influence of gravity for each joint angle. In the case of internal rotation, there was no substantial difference in the impact of the training sessions because the joint angle-force profiles for the machine group and control group showed similar tendencies (Kim 2014). When looking at external rotation, the profiles showed opposite tendencies.  This was similar with the finding that the machine group showed a greater improvement in exercise performance by maintaining consistent muscle activation throughout the exercise. Previous studies suggest that the effectiveness of a training load on the joint angle-torque relationship in elbow or knee joint exercises.
COR provides prevention and rehabilitation personal training programs for both athletes and your everyday weight lifters.  At COR we provide shoulder strengthening and soft tissue physical therapy programs.  By using body weight, rubber bands and weights in the training program, this can help maintain our strengths and improve our weaknesses.  Using a movement screening for everyone in the beginning, this can help pinpoint our weakness and make a proper and affective individualized program for each person. 
Reference:

1. Kim Y, Lee K, Moon J, Koo D, Park J, Kim K, Hong D, Shin I. Effect of Resistance Training Maintaining the Joint Angle-torque Profile Using a Haptic-based Machine on Shoulder Internal and External Rotation. J Phys Ther Sci. 2014 Apr;26(4):525-8.

Written by Chris Barber, CPT