scholarly journals The Coupled Kinematics of Scapulothoracic Upward Rotation

2019 ◽  
Author(s):  
Rebekah L Lawrence ◽  
Jonathan P Braman ◽  
Daniel F Keefe ◽  
Paula M Ludewig
Keyword(s):  
Muscle Function ◽  
Shape Matching ◽  
Coupling Function ◽  
Scapular Dyskinesis ◽  
Cross Sectional ◽  
Single Plane ◽  
Predominant Component ◽  
Shoulder Complex ◽  
Proportional Contribution ◽  
Kinematic Mechanisms

Abstract Background Scapulothoracic upward rotation (UR) is an important shoulder complex motion allowing for a larger functional work space and improved glenohumeral muscle function. However, the kinematic mechanisms producing scapulothoracic UR remain unclear, limiting the understanding of normal and abnormal shoulder movements. Objective The objective of this study was to identify the coupling relationships through which sternoclavicular and acromioclavicular joint motions contribute to scapulothoracic UR. Design This was a cross-sectional observational study. Methods Sixty participants were enrolled in this study; 30 had current shoulder pain, and 30 had no history of shoulder symptoms. Shoulder complex kinematics were quantified using single-plane fluoroscopy and 2D/3D shape matching and were described as finite helical displacements for 30-degree phases of humerothoracic elevation (30°–60°, 60°–90°, and 90°–120°). A coupling function was derived to estimate scapulothoracic UR from its component motions of acromioclavicular UR, sternoclavicular posterior rotation, and sternoclavicular elevation as a function of acromioclavicular internal rotation. The proportional contributions of each of the component motions were also calculated and compared between phases of humerothoracic elevation and groups. Results Scapulothoracic UR displacement could be effectively predicted using the derived coupling function. During the 30- to 60-degree humerothoracic elevation phase, acromioclavicular UR accounted for 84.2% of scapulothoracic UR, whereas sternoclavicular posterior rotation and elevation each accounted for <10%. During later phases, acromioclavicular UR and sternoclavicular posterior rotation each accounted for 32%–42%, whereas sternoclavicular elevation accounted for <11%. Limitations Error due to the tracking of sternoclavicular posterior rotation may have resulted in an underprediction of its proportional contribution and an overprediction of the proportional contribution of acromioclavicular UR. Conclusions Acromioclavicular UR and sternoclavicular posterior rotation are the predominant component motions of scapulothoracic UR. More research is needed to investigate how these coupling relationships are affected by muscle function and influenced by scapular dyskinesis.

BIOMECHANICAL MODEL PREDICTING VALUES OF MUSCLE FORCES IN THE SHOULDER GIRDLE DURING ARM ELEVATION

2010 ◽  
Vol 10 (04) ◽  
pp. 643-666 ◽  
Author(s):  
ERIC BERTHONNAUD ◽  
MELISSA MORROW ◽  
GUILLAUME HERZBERG ◽  
KAI-NAN AN ◽  
JOANNES DIMNET
Keyword(s):  
Geometric Modeling ◽  
Geometric Model ◽  
Contractile Element ◽  
Muscle Forces ◽  
Active Muscle ◽  
Cross Sectional ◽  
Shoulder Complex ◽  
Arm Elevation

A three-dimensional (3D) geometric model for predicting muscle forces in the shoulder complex is proposed. The model was applied throughout the range of arm elevation in the scapular plan. In vitro testing has been performed on 13 cadaveric shoulders. The objectives were to determine homogeneous values of physiological parameters of shoulder muscles and to locate sites of muscular attachment to any bone of the shoulder complex. Muscular fiber lengths, lengths of contractile element (CE), and muscle volumes were measured, corresponding physiological cross-sectional area (PCSA) were calculated, and force/length muscle relations were found. An in vivo biplanar radiography was performed on five volunteers. The photogrammetric reconstruction of bone axes and landmarks were coupled with a geometric modeling of bones and muscle sites of attachment. Muscular paths were drawn and changes in lengths during movement have been estimated. Directions of muscle forces are the same as that of muscular path at the point of attachment to bone. Magnitudes of muscular forces were found from muscle lengths coupled with force/length relations. Passive forces were directly determined contrary to active muscle forces. A resulting active muscle force is calculated from balancing weight and passive forces at each articular center. Active muscle forces were calculated by distributing the resulting force among active muscles based on the muscular PCSA values.

The Effects of Aging and Training on Skeletal Muscle

1998 ◽  
Vol 26 (4) ◽  
pp. 598-602 ◽  
Author(s):  
Donald T. Kirkendall ◽  
William E. Garrett
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Function ◽  
Cellular Level ◽  
Type I ◽  
Loss Of Function ◽  
Skeletal Muscle Function ◽  
Cross Sectional ◽  
Age Related ◽  
General Slowing

Aging results in a gradual loss of muscle function, and there are predictable age-related alterations in skeletal muscle function. The typical adult will lose muscle mass with age; the loss varies according to sex and the level of muscle activity. At the cellular level, muscles loose both cross-sectional area and fiber numbers, with type II muscle fibers being the most affected by aging. Some denervation of fibers may occur. The combination of these factors leads to an increased percentage of type I fibers in older adults. Metabolically, the glycolytic enzymes seem to be little affected by aging, but the aerobic enzymes appear to decline with age. Aged skeletal muscle produces less force and there is a general “slowing” of the mechanical characteristics of muscle. However, neither reduced muscle demand nor the subsequent loss of function is inevitable with aging. These losses can be minimized or even reversed with training. Endurance training can improve the aerobic capacity of muscle, and resistance training can improve central nervous system recruitment of muscle and increase muscle mass. Therefore, physical activity throughout life is encouraged to prevent much of the age-related impact on skeletal muscle.

scholarly journals Risk Factors Associated With Shoulder Pain and Disability Across the Lifespan of Competitive Swimmers

2012 ◽  
Vol 47 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Angela Tate ◽  
Gregory N. Turner ◽  
Sarah E. Knab ◽  
Colbie Jorgensen ◽  
Andrew Strittmatter ◽  
...  
Keyword(s):  
High School ◽  
Shoulder Pain ◽  
Age Groups ◽  
Muscle Length ◽  
Scapular Dyskinesis ◽  
Shoulder Injuries ◽  
Shoulder Injury ◽  
Cross Sectional ◽  
Pectoralis Minor ◽  
Competitive Swimmers

Context: The prevalence of shoulder pain among competitive swimmers is high, but no guidelines exist to reduce shoulder injuries. Elucidating differences between swimmers with and without shoulder pain can serve as a basis for the development of a program to prevent shoulder injury that might lead to pain and dysfunction. Objective: To determine whether physical characteristics, exposure, or training variables differ between swimmers with and without shoulder pain or disability. Design: Cross-sectional study. Setting: Multisite swimming centers. Patients or Other Participants: A total of 236 competitive female swimmers aged 8 to 77 years. Data Collection and Analysis: Participants completed the Penn Shoulder Score and underwent testing of core endurance, range of motion, muscle force production, and pectoralis minor muscle length and the Scapular Dyskinesis Test. Swimmers were grouped by age for analysis: ages 8 to 11 years (n = 42), 12 to 14 years (n = 43), 15 to 19 years (high school, n = 84), and 23 to 77 years (masters, n = 67). Comparisons were made between groups with and without pain and disability using independent t tests for continuous data and χ2 analyses and Fisher exact tests for categorical data. Results: Nine (21.4%) swimmers aged 8 to 11 years, 8 (18.6%) swimmers aged 12 to 14 years, 19 (22.6%) high school swimmers, and 13 (19.4%) masters swimmers had shoulder pain and disability. Differences that were found in 2 or more age groups between athletes with and without shoulder pain and disability included greater swimming exposure, a higher incidence of previous traumatic injury and patient-rated shoulder instability, and reduced participation in another sport in the symptomatic groups (P &lt; .05). Reduced shoulder flexion motion, weakness of the middle trapezius and internal rotation, shorter pectoralis minor and latissimus, participation in water polo, and decreased core endurance were found in symptomatic females in single varying age groups (P &lt; .05). Conclusions: Female competitive swimmers have shoulder pain and disability throughout their lives. Given that exposure and physical examination findings varied between athletes with and without substantial pain and disability, a program to prevent shoulder injury that might lead to pain and dysfunction appears warranted and might include exposure reduction, cross-training, pectoral and posterior shoulder stretching, strengthening, and core endurance training.

scholarly journals Scapular Dyskinesis in Young, Asymptomatic Elite Swimmers

2018 ◽  
Vol 6 (1) ◽  
pp. 232596711775081 ◽  
Author(s):  
Jacopo Preziosi Standoli ◽  
Francesco Fratalocchi ◽  
Vittorio Candela ◽  
Tiziano Preziosi Standoli ◽  
Giuseppe Giannicola ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Dynamic Test ◽  
Cross Sectional Study ◽  
Type I ◽  
Scapular Dyskinesis ◽  
Long Distance ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Overhead Athletes ◽  
Elite Swimmers

Background: Overhead athletes are at a greater risk of developing scapular dyskinesis (SD). Although swimming is considered an overhead sport, information regarding SD in these athletes is scarce. Purpose: To determine the prevalence of SD in young, asymptomatic elite swimmers. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 661 asymptomatic elite swimmers were enrolled in this study (344 male, 317 female; mean age, 15.83 ± 2.20 years). Anthropometric characteristics, training routine, and stroke specialty were recorded. SD was assessed using a dynamic test consisting of an examination of the shoulder blades throughout synchronous forward flexion motion in the sagittal plane and was deemed to be either present or absent. Each movement was repeated 5 times. These evaluations were performed with athletes at rest, before any training or competition. Statistical analysis was performed. Results: SD was detected in 56 (8.5%) participants. Type I SD was the most common (46.5%); male participants were 2 times as likely to have SD as female participants (39 male, 17 female; P < .01). No correlation was found between the dominant limb and side affected ( P = .258); rather, a correlation was found between the breathing side and side affected, in that swimmers with a preferred breathing side were more prone to develop SD in the opposite shoulder ( P < .05). Swimmers involved in long-distance races were found to have a greater risk of developing SD ( P = .01). Conclusion: SD may be an asymptomatic condition in elite young swimmers and is present in 8.5% of these athletes. Early diagnosis may be useful for asymptomatic athletes with SD and to avoid its possible evolution to a symptomatic condition.

Flexibility, Position, and Strength of the Shoulder Complex in Pediatric and Adult Amateur Tennis Athletes

2021 ◽  
pp. 1-9
Author(s):  
Germanna M. Barbosa ◽  
Larissa P. Ribeiro ◽  
Ana B. Nasser ◽  
Gretchen D. Oliver ◽  
Paula R. Camargo
Keyword(s):  
At Risk ◽  
Outcome Measures ◽  
External Rotation ◽  
Posterior Capsule ◽  
Serratus Anterior ◽  
Cross Sectional ◽  
Shoulder Range Of Motion ◽  
Cutoff Values ◽  
Shoulder Complex ◽  
Dominant Side

Context: Understanding the musculoskeletal adaptations in the shoulder complex of varying ages of tennis athletes may suggest preventive protocols and conditioning and rehabilitation programs to this population. This study aimed to generate a bilateral descriptive profile of shoulder flexibility, scapular and clavicular position, and muscle strength in pediatric and adult amateur tennis athletes. The outcome measures were compared between groups and sides. The number and percentage of athletes “at risk” according to cutoff values for shoulder range of motion (ROM) were also analyzed. Design: Cross-sectional study. Methods: 36 pediatric and 28 adult amateur tennis athletes were tested. Outcome measures were ROM of shoulder flexion, abduction, internal and external rotation, posterior capsule tightness, pectoralis minor index (PMI), scapular upward rotation, clavicular elevation, and strength of the external rotators, serratus anterior, and lower trapezius of the dominant/nondominant sides. Results: Pediatric athletes had greater dominant side external rotation (P = .01) and total ROM (P = .04), increased Low Flexion test (P = .01), and decreased PMI (P = .01) compared with the adults. Bilaterally, the pediatric athletes had greater dominant side external rotation ROM (P < .01) and decreased PMI (P = .002) as compared with their nondominant side, whereas the adults displayed lower values on posterior capsule tightness (P = .01) and decreased PMI (P = .02) on their dominant side compared with their nondominant side. For the remaining outcomes, no interaction effects were observed. The cutoff values for shoulder ROM showed that several athletes were “at risk” of shoulder problems. Conclusion: Upper extremity adaptations at the shoulder are present in both pediatric and adult tennis athletes. These data can assist clinicians in better understanding the biomechanical adaptations in the shoulder of amateur tennis athletes in different age groups.

Sign in / Sign up

Export Citation Format

Share Document