Evolution of muscular fatigue in periscapular and rotator cuff muscles during isokinetic shoulder rotations

Abstract

To this day, how shoulder muscles react to a strong fatigue stimulus during dynamic shoulder rotations remains unknown. The aims of this study were to assess the effect of repeated maximal internal-external isokinetic shoulder rotations on shoulder strength and muscle activity. Twenty-four individuals completed a 50-repetition fatiguing isokinetic protocol whileelectromyography was recorded on eleven muscles of the shoulder girdle. Time-frequency transformation and an ANOVA model using statistical parametric mapping methods were used to analyze shifts in instantaneous median frequency (MDF) between each 10-repetition Blocks. Peak torques decreased in both internal and external rotation (P < 0.01) by 24.8% on average which indicated the presence of fatigue. Significant decrease in MDF (P < 0.01) was observed for pectoralis, middle deltoid, upper, middle and lower trapezius, infraspinatus and subscapularis muscles. The observed fatigue to the periscapular and rotator cuff muscles suggests that shoulder stability could be compromised during repeated shoulder rotations, which could underlie the increased risk of scapular dyskinesis and shoulder impingement during fatiguing tasks. The present study provides a deeper understanding on the manifestations of fatigue within muscles of the shoulder girdle and the results could be applied toward improvements in athlete shoulder injury prevention and rehabilitation programs.

An Optimization Method Tracking EMG, Ground Reactions Forces, and Marker Trajectories for Musculo-Tendon Forces Estimation in Equinus Gait

“…Raw EMG signals were band pass filtered (4th order) between 30 and 300 Hz, rectified, and EMG envelops were obtained by a 4th order low-pass Butterworth filter with a cut-off frequency of 25 Hz. EMG envelops were then normalized to their respective maximal voluntary activation (Gaudet et al, 2018).…”

Scapular Dyskinesis: From Basic Science to Ultimate Treatment

“…Clinically, the consequent loss of strength was appreciated by the lesser upward rotation and the greater IR of the scapula [53,54]. Stabilizer muscle fatigue seems to decrease RC strength and to increase SD symptoms [55][56][57]. However, in comparison to patients without SD, no significant difference in ultimate muscle strength was observed, probably because upper trapezius strength can rebalance altered movements [55,58].…”

Strength Abilities in Sports Swimming a Systematic Review

“…During the analysis of the available national and international literature, numerous materials were found concerning isokinetic studies of the shoulder joint of competitive swimmers, in internal and external rotation movements only (Rupp et al, 1995;Bak and Magnusson, 1997;Swanik et al, 2002a;Ramsi et al, 2004;West et al, 2005;Gozlan et al, 2006;Olivier et al, 2008;Batalha et al, 2012Batalha et al, , 2013Batalha et al, , 2014Batalha et al, , 2015aBatalha et al, , 2015bWiażewicz, 2015;Wiażewicz and Kolbowicz, 2015;Dekerle and Pat-erson, 2016;Wiażewicz and Czekała, 2017;Gaudet et al, 2018;Liaghat et al, 2018). Significantly fewer literature items were related to comprehensive studies, i.e.…”

“…Additionally, it was recognised that peak torque may not be an entirely appropriate determinant of shoulder muscle strength symmetry. Gaudet et al (2018) attempted to assess the effect of repeated maximal internal and external arm rotations, on muscle strength and activity. The rotations were performed in an isokinetic mode.…”

“…Numerous authors (Ramsi et al, 2004;Walker et al, 2012;Batalha et al, 2013Batalha et al, , 2015aBatalha et al, , 2015bGaudet et al, 2018) indicate that swimming techniques may be the cause of shoulder muscle strength misalignment and advocate the introduction of compensatory programmes, due to the disruption of the agonist/antagonist ratio. The literature (Richardson et al, 1980;McMaster and Troup, 1993;Weldon and Richardson, 2001;Blanch, 2004;Wolf et al, 2009;Bak, 2010;Habechian et al, 2018) cites rotator cuff strength imbalance as one of the risk factors for shoulder injury in swimmers.…”