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Avoiding high‐risk rotator cuff loading: Muscle force during three pull‐up techniques
Author(s) -
Urbanczyk Caryn A.,
Prinold Joseph A. I.,
Reilly Peter,
Bull Anthony M. J.
Publication year - 2020
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.13780
Subject(s) - biceps , biomechanics , range of motion , rotator cuff , medicine , shoulder girdle , physical medicine and rehabilitation , scapula , shoulders , kinematics , repeated measures design , physical therapy , anatomy , surgery , mathematics , statistics , physics , classical mechanics
Heavily loaded overhead training tasks, such as pull‐ups are an effective strength training and rehabilitation exercise requiring high muscle forces maintained over a large range of motion. This study used experiments and computational modeling to examine loading patterns during three different pull‐up variants and highlighted risks to vulnerable musculoskeletal structures. Optical motion tracking and a force platform captured kinematics and kinetics of 11 male subjects with no history of shoulder pathology, during performance of three pull‐up variants—pronated front grip, pronated wide grip, and supinated reverse grip. UK National Shoulder model (UKNSM) simulated biomechanics of the shoulder girdle. Muscle forces and activation patterns were analyzed by repeated measures ANOVA with post‐hoc comparisons. Motor group recruitment was similar across all pull‐up techniques, with upper limb depression occurring secondary to torso elevation. Stress‐time profiles show significant differences in individual muscle patterns among the three pull‐up variants, with the most marked differences between wide grip and reverse grip. Comparing across techniques, latissimus dorsi was relatively more active in wide pull‐ups ( P < .01); front pull‐ups favored activation of biceps brachii and brachialis ( P < .02); reverse pull‐ups displayed higher proportional rotator cuff activation ( P < .01). Pull‐ups promote stability of the shoulder girdle and activation of scapula stabilizers and performing pull‐ups over their full range of motion is important as different techniques and phases emphasize different muscles. Shoulder rehabilitation and strength & conditioning programs should encourage incorporation of all three pull‐up variants with systematic progression to provide greater global strengthening of the torso and upper limb musculature.