Biomechanical Validation of Push-up and Pull-up Progression Program

A primary goal of rehabilitation is to return physically active individuals back to their normal level of function. Physically active individuals are participating in a wide variety of activities beyond sports but still many traditional exercises, such as push-up and pull-ups, are required. Although these exercises have been used to evaluate muscular endurance for decades the specific biomechanical demands on the shoulder, elbow, and wrist are not well established. A more comprehensive understanding of the biomechanical demands on the entire upper extremity kinetic chain would facilitate a scientifically based exercise prescription during rehabilitation. Therefore, the purpose of this study is to determine the biomechanical demands placed on the shoulder, elbow, and wrist during two critical upper extremity exercises to establish appropriate functional progressions for physically active individual returning from injury or surgery. The first aim of this study is to describe the electromyographical activation levels of the shoulder, elbow, and forearm musculature during various pull-up and push-up exercises. We hypothesize that muscular amplitude levels will provide evidence on how these exercises differentially load the upper extremity musculotendinous structures. The second aim will describe the linear and angular loading characteristics at the shoulder, elbow, and wrist joints during various pull-up and push-up exercises. Twenty-five healthy subjects between the ages of 18-45 years of age that demonstrate the ability to complete at least five pull-ups and push-ups will be recruited for this study. Subjects will be excluded from the study if they report an upper extremity injury or surgery within the past two years. Subjects will be excluded if range of motion of wrist, elbow, and shoulder are not within normal limits bilaterally. Subjects will be outfitted with retroreflective markers to track motion. Electromyography electrodes will be placed on the skin to collect muscle activation for the dominant latissimus dorsi, pectoralis major, anterior deltoid, serratus anterior, biceps brachii, triceps brachii, flexor carpi ulnaris, and extensor carpi radialis. Fine wire electrodes will be placed in the subject’s supraspinatus, infraspinatus, and subscapularis. A pull-up bar will be constructed in order to collect loads on the shoulders during the pull-up exercises. Each subject will complete a series of four pull-up and four push-up variations. The pull-up exercises will include full pull-up in a supinated grip, full pull-up in a pronated grip, isometric holds in the midrange, and dead hangs (isometric holds with elbow extended). The push-up exercises will include a modified-knee, standard, wide, and narrow push-ups. Five repetitions each exercise will be completed in random order. Comparisons of shoulder, elbow, and wrist torques and muscle activation will be conducted to determine if significant differences in loading and muscle activation exist between the variations of each exercise. The establishment of muscle activation and loading characteristics for each exercise will allow clinicians to determine a logical push-up and pull-up exercise progression based on invivo loading characteristics. This data is critical for the establishment of an evidence based return activity or sport program.