Scapula kinematics of pull-up techniques: Avoiding impingement risk with training changes.

Area of Science:

• Biomechanics
• Sports Medicine
• Kinesiology

Background:

• Overhead athletic activities are associated with shoulder pathology.
• Scapula dyskinesia is a common precursor to shoulder injuries.
• Pull-ups are a prevalent exercise for overhead athletes, with varying techniques.

Purpose of the Study:

• To quantify scapular kinematics and external forces during three distinct pull-up techniques.
• To analyze the potential injury implications of different pull-up variations.

Main Methods:

• An observational study involving eleven regular pull-up participants.
• Analysis of upward pull-up motions using three techniques: palms anterior, palms posterior (reverse), and wide-grip.
• Scapular kinematics were tracked using a skin-fixed technique with retro-reflective markers.

Main Results:

• High intra-participant repeatability was observed for humerothoracic and scapulothoracic rotations.
• Significantly different kinematic patterns were noted between pull-up techniques.
• Reverse grip pull-ups exhibited extreme glenohumeral rotation, while wide-grip pull-ups showed reduced scapular protraction/retraction, both suggesting increased impingement risk.

Conclusions:

• The employed scapula tracking technique demonstrated high repeatability.
• High arm elevation during pull-ups narrows sub-acromial space, increasing impingement injury risk.
• Wide and reverse grip pull-ups present kinematic patterns associated with higher impingement risk; assisted front pull-ups warrant further investigation.