Effects of Scapular Kinetic-Chain Exercise on Muscle Activity in Overhead-Pitching Baseball Players

Author(s):  
Ki-Jae SONG ◽  
Jin-Ho YOON ◽  
Jae-Keun OH

Background: We aimed to demonstrate the effect of 8 wk of scapular kinetic-chain exercise on muscle activity in collegiate baseball players diagnosed with scapular dyskinesis. Methods: The subjects were career baseball players with at least a 7-year career assigned into either a SICK (S; scapular malposition, I; inferior border prominence, C; coracoid process pain, K; scapular dyskinesis; n=7) group or a normal group (n=16), respectively. The groups were further divided into SICK-Dominant, SICKNon-Dominant, Normal-Dominant, and Normal-Non-Dominant to examine the dominant and non-dominant deviation of each group. Twenty-three subjects finally recruited through the Sports Science Institute of Korea National Sport University, Seoul, Korea in Sep 2014. Subjects were only allowed drug treatment for acute injuries during matches or training, and matches, training, and diet were controlled by university dormitory life. Results: There was a significant increase in maximal muscular activation (MA) in elevation motion of NormalDominant upper trapezii (UT), mean MA of SICK-Dominant UT, and mean MA of SICK-Dominant lower trapezii (LT) (P<0.05). In depression motion, the mean MAs of SICK-Dominant, Normal-Dominant, and Normal-Non-Dominant UT were significantly increased (P<0.05). The maximal MA of Normal-Dominant LT was significantly increased (P=0.029), and the SICK-Dominant and Normal-Dominant groups showed significantly higher maximal and mean MAs after exercise compared with the Normal-Non-Dominant group (P<0.05). The maximal MA of SICK-Dominant musculi serratus anterior was significantly lower than NormalDominant at pre-test (P=0.034), and the mean MA of SICK-Dominant musculi serratus anterior differed from Normal-Dominant and Normal-Non-Dominant (P<0.05) before testing, but only from Normal-Non-Dominant after testing (P=0.031). Conclusion: Scapular kinetic-chain exercise improved muscle activation in both overhead-pitching players with scapular dyskinesis and normal players.

2008 ◽  
Vol 43 (5) ◽  
pp. 464-469 ◽  
Author(s):  
W. Steven Tucker ◽  
Brian M. Campbell ◽  
Erik E. Swartz ◽  
Charles W. Armstrong

Abstract Context: The Cuff Link is a closed kinetic chain rehabilitation apparatus for the upper extremity. Limited research has established its effectiveness to elicit muscle activation of the scapular muscles. Objective: To determine if scapular muscle activation differs in response to 2 upper extremity closed kinetic chain exercises: Cuff Link and standard push-up. Design: A single-group, repeated-measures design. Setting: Controlled laboratory. Patients or Other Participants: Twenty-eight healthy individuals (13 women: age  =  19.69 ± 1.55 years, height  =  167.44 ± 9.52 cm, mass  =  61.00 ± 8.79 kg; 15 men: age  =  22.00 ± 3.91 years, height  =  181.44 ± 6.60 cm, mass  =  82.36 ± 13.23 kg) with no history of shoulder or low back injury volunteered to participate in this study. Intervention(s): Participants performed 10 trials of complete revolutions on the Cuff Link and 10 full–weight-bearing push-ups. We controlled trial velocity and randomized order. Trunk and shoulder positions were normalized to the participant's height. Using surface electromyography, we recorded muscle activity of the serratus anterior, middle trapezius, and lower trapezius. Rectified and smoothed electromyography data for the serratus anterior, middle trapezius, and lower trapezius were normalized as a percentage of the maximal voluntary isometric contractions (%MVIC). Main Outcome Measure(s): Mean muscle activity of the serratus anterior, middle trapezius, and lower trapezius. We used paired-samples t tests to analyze the mean data for each condition. The α level was adjusted to .016 to avoid a type I error. Results: Middle trapezius %MVIC was greater during push-ups (27.01 ± 20.40%) than during use of the Cuff Link (11.49 ± 9.46%) (P  =  .001). Lower trapezius %MVIC was greater during push-ups (36.07 ± 18.99%) than during use of the Cuff Link (16.29 ± 8.64%) (P  =  .001). There was no difference in %MVIC for the serratus anterior between conditions. Conclusions: The push-up demonstrated greater middle trapezius and lower trapezius activation levels compared with the Cuff Link. However, the push-up had a high participant failure rate. Because serratus anterior activation levels were similar, the Cuff Link may be an appropriate alternative for individuals lacking the upper body strength to perform a push-up.


Biomechanics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 202-213
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Alana J. Turner ◽  
Reuben F. Burch V ◽  
Adam C. Knight ◽  
...  

Background: Occupational footwear and a prolonged duration of walking have been previously reported to play a role in maintaining postural stability. The purpose of this paper was to analyze the impact of three types of occupational footwear: the steel-toed work boot (ST), the tactical work boot (TB), and the low-top work shoe (LT) on previously unreported lower extremity muscle activity during postural stability tasks. Methods: Electromyography (EMG) muscle activity was measured from four lower extremity muscles (vastus medialis (VM), medial hamstrings (MH), tibialis anterior (TA), and medial gastrocnemius (MG) during maximal voluntary isometric contractions (MVIC) and during a sensory organization test (SOT) every 30 min over a 4 h simulated workload while wearing ST, TB, and LT footwear. The mean MVIC and the mean and percentage MVIC during each SOT condition from each muscle was analyzed individually using a repeated measures ANOVA at an alpha level of 0.05. Results: Significant differences (p < 0.05) were found for maximal exertions, but this was limited to only the time main effect. No significant differences existed for EMG measures during the SOT. Conclusion: The findings suggest that occupational footwear type does not influence lower extremity muscle activity during both MVIC and SOT. Significantly lower muscle activity during maximal exertions over the course of the 4 h workload was evident, which can be attributed to localized muscular fatigue, but this was not sufficient to impact muscle activity during postural stability tasks.


Author(s):  
Kara-Lyn R. Harrison ◽  
Paolo Sanzo ◽  
Carlos Zerpa ◽  
Taryn Klarner

Due to the repetitive high forces and torques placed on an individual during a baseball pitch, shoulder pain is present in 46-57% of pitchers. Therapeutic taping has been proposed to have beneficial qualities in injury prevention, rehabilitation, and performance enhancement via muscular facilitation. Therefore, the purpose of this pilot study was to investigate the effect of taping on the velocity of an overhead baseball throw and muscle activation patterning of the supraspinatus, infraspinatus, and pectoralis major muscles in baseball players after muscle fatigue was induced. Participants were asked to complete three pre-test maximum velocity overhead throws, a fatiguing protocol, followed by three post-test maximum velocity pitches. There was no statistically significant difference in throwing velocity or muscle activity with the application of the different taping conditions in the three phases of an overhead baseball throw. These finding suggest Kinesio Tape® does not change muscle activation or velocity of overhead baseball throws when compared to a no tape condition.


2020 ◽  
Vol 55 (3) ◽  
pp. 265-273
Author(s):  
Wan-Yu Du ◽  
Tsun-Shun Huang ◽  
Yuan-Chun Chiu ◽  
Szu-Jieh Mao ◽  
Li-Wei Hung ◽  
...  

Context Subacromial impingement syndrome (SIS) is associated with scapular dyskinesis, or imbalanced scapular muscle activity. Evidence has shown that feedback can improve scapular control in patients with SIS. However, it is unknown whether real-time video feedback or electromyography (EMG) biofeedback is optimal for improving scapular kinematics and muscle activity during a functional task. Objective To compare the effects of video and EMG feedback sessions on absolute muscle activity (upper trapezius [UT], lower trapezius [LT], serratus anterior), muscle balance ratios (UT/LT, UT/serratus anterior), and scapular kinematics (anterior-posterior tilt, external-internal rotation, upward rotation) in SIS participants during arm elevation and lowering. Design Randomized controlled clinical trial. Setting Research laboratory. Patients or Other Participants Overhead athletes who were diagnosed with SIS and who also exhibited scapular dyskinesis (N = 41). Main Outcome Measure(s) Three-dimensional kinematics and EMG were recorded before and after feedback training. Results Lower trapezius muscle activity increased (4.2%–18%, P &lt; .011) and UT/LT decreased (0.56–1.17, P &lt; .013) in the EMG biofeedback training group as compared with those in the video feedback training group. Scapular upward rotation during arm elevation was higher in the video group than in the EMG group after feedback training (2.3°, P = .024). Conclusions The EMG biofeedback improved muscle control and video feedback improved the correction of scapular upward rotation in patients with SIS. Trial Registration Number ClinicalTrials.gov: NCT03252444.


2021 ◽  
pp. 175857322110193
Author(s):  
Katie L Kowalski ◽  
Denise M Connelly ◽  
Jennifer M Jakobi ◽  
Jackie Sadi

Background Push-ups (PU) are a common closed chain exercise used to enhance shoulder girdle stability, with variations that alter the difficulty or target specific muscles. To appropriately select and prescribe PU exercises, an understanding of muscle activity during variations of the PU is needed. The purpose of this scoping review was to identify common PU variations and describe their muscle activation levels. Methods Databases searched included PubMed, CINAHL, Scopus, and SPORTDiscus for articles published between January 2000 and November 2019. Results Three hundred three articles were screened for eligibility with 30 articles included in the analysis. Six PU types and five muscles met the criteria for analysis. Weighted mean electromyography (EMG) amplitude was calculated for each muscle across PU types and for each PU type as a measure of global muscle activity. Triceps and pectoralis major had the highest EMG amplitude during unstable, suspension, incline with hands on a ball and the standard PU. Serratus anterior had the highest EMG amplitude during PU plus and incline PU. The greatest global EMG amplitude occurred during unstable surface PU. Discussion These results provide clinicians with a framework for prescribing PU to target specific muscles and scale exercise difficulty to facilitate rehabilitation outcomes.


2011 ◽  
Vol 20 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Justin M. Stanek ◽  
Todd A. McLoda ◽  
Val J. Csiszer ◽  
A.J. Hansen

Context:Selected muscles in the kinetic chain may help explain the body’s ability to avert injury during unexpected perturbation.Objective:To determine the activation of the ipsilateral rectus femoris (RF), gluteus maximus (MA), gluteus medius (ME), and contralateral external obliques (EO) during normal and perturbed gait.Design:Single-factor, repeated measures.Setting:University research laboratory.Participants:32 physically active, college-age subjects.Intervention:Subjects walked a total of 20 trials the length of a 6.1-m custom runway capable of releasing either side into 30° of unexpected inversion. During 5 trials, the platform released into inversion.Main Outcome Measures:Average, peak, and time to peak EMG were analyzed across the 4 muscles, and comparisons were made between the walking trials and perturbed trials.Results:Significantly higher average and peak muscle activity were noted for the perturbed condition for RF, MA, and EO. Time to peak muscle activity was faster during the perturbed condition for the EO.Conclusion:Rapid contractions of selected postural muscles in the kinetic chain help explain the body’s reaction to unexpected perturbation.


2021 ◽  
pp. 036354652110250
Author(s):  
Kelly R. Berckmans ◽  
Birgit Castelein ◽  
Dorien Borms ◽  
Thierry Parlevliet ◽  
Ann Cools

Background: Scapular muscle activity during shoulder exercises has been explored with surface electromyography (EMG). However, knowledge about the activity of deeper-layer scapular muscles is still limited. Purpose: To investigate EMG activation of the deeper-layer scapular stabilizers (levator scapulae [LS], rhomboid major [RM], pectoralis minor [Pm] muscles) together with superficial muscle activity (upper [UT], middle [MT], and lower trapezius [LT] and serratus anterior [SA]) during 4 exercises often used for training scapular function. Based on the amplitude EMG of the deeper-layer muscles, scapular muscle activation ratios for the 4 exercises were calculated, hereby providing knowledge of the optimal muscle balance. Study Design: Descriptive laboratory study. Methods: A total of 26 healthy participants performed 4 shoulder exercises (side-lying external rotation [ER], side-lying forward flexion, prone horizontal abduction with ER, and prone extension) while simultaneously measuring scapular muscle activity. Intramuscular electrodes were used for the deeper layer, in contrast to surface electrodes for the superficial muscles. All data were normalized to percentage of maximal voluntary isometric contraction (%MVIC), and the activation ratios (the muscle activity of the deeper layer relative to the other muscles) were calculated. A 1-way analysis of variance with Bonferroni correction was applied for statistical analysis. Results: Moderate activity was found in all exercises for the LS and RM (25%-45% MVIC). The Pm resulted in low activity during both side-lying exercises (13%-18% MVIC). Ratios involving LS or RM showed values >1 for all exercises (1.28-12.41) except for LS/MT, LS/LT, and LS/RM (0.85-0.98) during side-lying ER, and LS/MT, RM/MT and RM/LS (0.85-0.99) during side-lying forward flexion. Likewise, values <1 were found when MT (0.85) and LS (0.99) were involved with RM in the numerator during side-lying forward flexion. Ratios with Pm in the numerator showed values <1, apart from the ratios with UT and SA in the denominator. Conclusion: The study provides extended knowledge about the deeper-layer scapular muscle activity and related ratios during the 4 shoulder exercises mentioned here. Putting theory into practice, based on our results, we advise both side-lying exercises to be performed to strengthen LT and MT, even in case of hyperactivity of the Pm. However, the 4 exercises should be given carefully to patients with hyperactivity in the LS and/or RM. Clinical Relevance: The findings of this study may assist clinical decision making in exercise selection for restoring scapular function.


Sign in / Sign up

Export Citation Format

Share Document