Scapular taping alters kinematics in asymptomatic subjects

BackgroundScapular taping is frequently used in the management of shoulder pain and as a part of injury prevention strategies in sports. It is believed to alter scapular kinematics and restore normal motion. However, there is little evidence to support its use. The aim of the study was to investigate the effect of shoulder taping on the scapular kinematics of asymptomatic subjects.MethodThirteen asymptomatic subjects performed elevations in the sagittal and scapular planes with no tape and after the application of tape. A motion tracking system and a scapula locator method were used to measure the shoulder movement. Co-ordinate frames were defined for the thorax, humerus and scapula and Euler angles were used to calculate joints rotations.ResultsScapular taping increased the scapular external and upward rotations and posterior tilt in elevations in the sagittal plane (p < 0.001). In the scapular plane, taping increased scapular external rotation (p < 0.05).ConclusionsTaping affects scapulothoracic kinematics in asymptomatic subjects. The effect may be different for different planes of movement. The findings have implications on the use of taping as a preventive measure in high-risk groups. Further work is needed to assess the effect of taping on symptomatic populations.     

Difference between palpation and optoelectronics recording of scapular motion

The aim of this study is to determine the errors of scapular localisation due to skin relative to bone motion with an optoelectronic tracking system. We compared three-dimensional (3D) scapular positions obtained with skin markers to those obtained through palpation of three scapular anatomical landmarks. The scapular kinematics of nine subjects were collected. Static positions of the scapula were recorded with the right arm elevated at 0°, 40°, 80°, 120° and 160° in the sagittal plane. Palpation and subsequent digitisation of anatomical landmarks on scapula and thorax were done at the same positions. Scapular 3D orientation was also computed during 10 repeated movements of arm elevation between 0° and 180°. Significant differences in scapular kinematics were seen between static positions and palpation when considering anterior/posterior tilt and upward/downward rotation at angles over 120° of humeral elevation and only at 120° for internal/external rotation. There was no significant difference between positions computed during static positions and during the movement for the three scapular orientations. A rotation correction model is presented in order to reduce the errors between static position and palpation measurement.     

Ratio between 3D glenohumeral and scapulothoracic motions in individuals without shoulder pain

This study determined the ratio between glenohumeral and three-dimensional scapular motion during arm elevation and lowering in 91 individuals without shoulder pain. Scapular kinematics were assessed using an electromagnetic tracking device. Individuals performed 3 repetitions of elevation and lowering of the arm in the sagittal plane. Two-way ANOVAs (interval: 30–60°, 60–90°, 90–120° x phase: elevation and lowering) and paired t-tests were used for data analysis. For scapular internal/external rotation, lesser scapular internal rotation contribution was found during the 60–90° interval as compared to the 90–60° interval. Lesser scapular external rotation was identified in the 60–30° interval of arm lowering. The ratio was greater during arm elevation (1.89) compared to lowering (1.74) across the entire motion arc. For scapular upward rotation, greater upward rotation contribution was observed during arm elevation at the 30–60° interval, and less scapular downward rotation contribution in the final range of arm lowering. For scapular tilt, lesser scapular posterior tilt contribution during arm elevation was observed compared to arm lowering. The ratios between glenohumeral elevation/lowering and each individual scapulothoracic motion showed either differences between intervals and/or between elevation and lowering during specific intervals in healthy individuals.     

Measurement of Dynamic Scapular Kinematics Using an Acromion Marker Cluster to Minimize Skin Movement Artifact

The measurement of dynamic scapular kinematics is complex due to the sliding nature of the scapula beneath the skin surface. The aim of the study was to clearly describe the acromion marker cluster (AMC) method of determining scapular kinematics when using a passive marker motion capture system, with consideration for the sources of error which could affect the validity and reliability of measurements. The AMC method involves placing a cluster of markers over the posterior acromion, and through calibration of anatomical landmarks with respect to the marker cluster it is possible to obtain valid measurements of scapular kinematics. The reliability of the method was examined between two days in a group of 15 healthy individuals (aged 19-38 years, eight males) as they performed arm elevation, to 120°, and lowering in the frontal, scapular and sagittal planes. Results showed that between-day reliability was good for upward scapular rotation (Coefficient of Multiple Correlation; CMC = 0.92) and posterior tilt (CMC = 0.70) but fair for internal rotation (CMC = 0.53) during the arm elevation phase. The waveform error was lower for upward rotation (2.7° to 4.4°) and posterior tilt (1.3° to 2.8°), compared to internal rotation (5.4° to 7.3°). The reliability during the lowering phase was comparable to results observed during the elevation phase. If the protocol outlined in this study is adhered to, the AMC provides a reliable measurement of upward rotation and posterior tilt during the elevation and lowering phases of arm movement.     

Reliability and validity of measuring scapular upward rotation using an electrical inclinometer

The aim of this study was to assess the reliability and validity of a modified two-dimensional electrical inclinometer to measure scapular upward rotation during static humeral elevation. Numerous techniques have been proposed to qualitatively and quantitatively measure upward rotation of the scapula. These techniques are limited by expense or an inability to be synchronized with other measurements, such as muscle activity and force output. For validity testing, static scapular upward rotation was measured separately with a digital protractor and electrical inclinometer while participants were at rest and 60°, 90° and 120° of humeral elevation in the scapular plane. For reliability testing, either 20 min before or 20 min after validity testing, participants performed the testing positions while measurements were taken with the electrical inclinometer only. Significant correlations existed between the modified electrical inclinometer and digital protractor at all four positions (r>0.996, p<0.001). The electrical inclinometer demonstrated good to excellent intra-rater reliability (ICC(3,1)>0.892, 95%CI: 0.785-0.988 and SEM<1.8°). These results support the use of the electrical inclinometer to measure scapular upward rotation. These findings provide clinicians and researchers with a practical instrument that can accurately measure scapular upward rotation in synchrony with other measurements, such as electromyography and isokinetic data.     

Effects of trunk rotation on scapular kinematics and muscle activity during humeral elevation

Trunk rotation often accompanies humeral elevation, during daily activities as well as sports activities. Earlier studies have demonstrated that changes in spinal posture contribute to scapular motion during humeral elevation. However, the effect of trunk rotation on scapular kinematics during humeral elevation has received scant attention. This study aimed to clarify how trunk rotation affects scapular kinematics and muscle activities during humeral elevation. Electromagnetic motion capture and electromyography were used to assess scapular and clavicular motion and muscle activity in the right and left sides of 12 healthy young men. The subjects were seated and instructed to elevate both arms with the trunk in neutral, ipsilaterally rotated, or contralaterally rotated position. Ipsilaterally rotated trunk position decreased the internal rotation (by 5°, relative to neutral trunk position) and increased the upward rotation (by 4°, relative to neutral trunk position) of the scapula. Trunk position did not affect clavicular motion during humeral movement. Electromyography showed that contralaterally rotated trunk position increased the activity of the upper trapezius and serratus anterior muscles and decreased the activity of the lower trapezius. Therapists should consider the importance of trunk rotation, which may be the key to developing more efficient rehabilitation programs.     

Scapular kinematics during unloaded and maximal loaded isokinetic concentric and eccentric shoulder flexion and extension movements

Characterization of scapular kinematics under demanding load conditions might aid to distinguish between physiological and clinically relevant alterations. Previous investigations focused only on submaximal external load situations. How scapular movement changes with maximal load remains unclear. Therefore, the present study aimed to evaluate 3D scapular kinematics during unloaded and maximal loaded shoulder flexion and extension. Twelve asymptomatic individuals performed shoulder flexion and extension movements under unloaded and maximal concentric and eccentric loaded isokinetic conditions. 3D scapular kinematics assessed with a motion capture system was analyzed for 20° intervals of humeral positions from 20° to 120° flexion. Repeated measures ANOVAs were used to evaluate kinematic differences between load conditions for scapular position angles, scapulohumeral rhythm and scapular motion extent. Increased scapular upward rotation was seen during shoulder flexion and extension as well as decreased posterior tilt and external rotation during eccentric and concentric arm descents of maximal loaded compared to unloaded conditions. Load effects were further seen for the scapulohumeral rhythm with greater scapular involvement at lower humeral positions and increased scapular motion extent under maximal loaded shoulder movements. With maximal load applied to the arm physiological scapular movement pattern are induced that may imply both impingement sparing and causing mechanisms.     

A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements

The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual’s anthropometry. We compared the model to “gold standard” bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models.     

A systematic review of 3D scapular kinematics and muscle activity during elevation in stroke subjects and controls

Through the onset of post-stroke motor disorders, the normal scapular function is compromised. As a result, shoulder pain and associated upper limb dysfunctions frequently arise after stroke.This review aimed to provide a systematic overview of available literature on scapular function, i.e. scapular three-dimensional (3D) kinematics and muscle activity during elevation, in healthy persons, persons with primary shoulder disorders and post-stroke patients. 3D scapular kinematics have been widely reported in healthy persons and persons with primary shoulder disorders, whereby a general pattern of upward rotation and posterior tilt during elevation has been agreed upon. Results on scapular internal/external rotation are inconsistent. In a post-stroke population, 3D scapular kinematics are less frequently reported. Scapular muscle activity has thus far been studied to very limited extend and firm conclusions could not be drawn.Although 3D scapular kinematics and muscle activity registrations are being increasingly used, some general methodological aspects should be considered. While the International Society of Biomechanics already proposed recommendations on the definition of upper limb joint coordinate systems and rotation sequences, proper result comparison necessitates further guidelines on other methodological aspects, i.e. data collection, processing, analyzing, and reporting.     

Validation of a video-based motion analysis technique in 3-D dynamic scapular kinematic measurements

BackgroundCurrent non-invasive 3-D scapular kinematic measurement techniques such as electromagnetic tracking are subjected to restrictions of wired sensors and limited capture space. Video-based motion analysis provides greater freedom with relatively less movement restriction. However, video-based motion analysis was rarely used in and not validated for scapular kinematics.MethodsScapular kinematics of five subjects performing abduction, scaption, and internal/external rotation was captured simultaneously with video-based motion analysis and dynamic stereo X-ray, a gold standard for tracking scapular movements. The data from video-based motion analysis was correlated with the data from dynamic stereo X-ray for validity evaluation.FindingsStrong and significant correlations were identified in scapular protraction/retraction and medial/lateral rotation during abduction and scaption, and scapular medial/lateral rotation and anterior/posterior tilt during internal/external rotation.InterpretationVideo-based motion analysis is valid for evaluating a single subject's scapular movement pattern in protraction/retraction during abduction and scaption, and medial/lateral-rotation during internal/external rotation. Anterior/posterior-tilt during abduction and scaption should be investigated with caution. Video motion analysis is also valid for evaluating group average of scapular kinematics except for protraction/retraction during internal/external rotation. While acknowledging the inherent limitations, video-based motion analysis is an appropriate technique for tracking scapular kinematics.     

Objective classification of scapular kinematics in participants with movement faults of the scapula on clinical assessment

The aim of this study was to assess the potential of employing a classification tool to objectively classify participants with clinically assessed movement faults (MFs) of the scapula. Six participants with a history of shoulder pain with MFs of the scapula and 12 healthy participants with no movement faults (NMFs) performed a flexion movement control test of the scapula, while scapular kinematic data were collected. Principal component scores and discrete kinematic variables were used as input into a classifier. Five out of the six participants with a history of pain were successfully classified as having scapular MFs with an accuracy of 72%. Variables related to the upward rotation of the scapula had the most influence on the classification. The results of the study demonstrate the potential of adopting a multivariate approach in objective classification of participants with altered scapular kinematics in pathological groups.     

Comparison of two trunk electromagnetic sensor placement methods during shoulder motion analysis

For kinematic studies of the shoulder, electromagnetic sensors are commonly placed on the humerus, scapula, and trunk. The trunk sensor is used to describe humeral and scapular kinematics with respect to the trunk. There are two common trunk sensor placements, the sternum or third thoracic vertebrae (T3). It is currently unclear if placement of the trunk sensor affects kinematics, making it difficult to compare data across studies. The purpose of this study was to compare two trunk sensor placements (T3 and sternum) on trunk and scapular kinematics during arm elevation. An electromagnetic tracking system was used to collect kinematic data during five consecutive repetitions of ascending and descending arm elevation in the sagittal plane. The results indicate that trunk sensor placement had no significant effect on trunk kinematics or scapular upward/downward rotation and internal/external rotation. Scapular anterior/posterior tilt was significantly greater when the trunk sensor was on the sternum compared to the T3 vertebrae during ascending 30°–120°: mean difference = −3.51° (95%CI: −5.61, −1.40), and descending 120°–30°: mean difference = −3.27° (95%CI: −6.07, −0.48). However, the difference in anterior/posterior tilt did not exceed the error (minimal detectable change), and thus is likely not a meaningful difference. These results indicate the trunk sensors can be affixed on T3 or the sternum, depending on the needs of the study.     

Effects of shoulder muscle fatigue caused by repetitive overhead activities on scapulothoracic and glenohumeral kinematics.

The purpose of this study was to determine the effects of shoulder muscle fatigue on three dimensional scapulothoracic and glenohumeral kinematics. Twenty healthy subjects participated in this study. Three-dimensional scapulothoracic and glenohumeral kinematics were determined from electromagnetic sensors attached to the scapula, humerus, and thorax. Surface electromyographic (EMG) data were collected from the upper and lower trapezius, serratus anterior, anterior and posterior deltoid, and infraspinatus muscles. Median power frequency (MPF) values were derived from the raw EMG data and were used to indicate the degree of local muscle fatigue. Kinematic and EMG measures were collected prior to and immediately following the performance of a shoulder elevation fatigue protocol. Following the performance of the fatigue protocol subjects demonstrated more upward and external rotation of the scapula, more clavicular retraction, and less humeral external rotation during arm elevation. All muscles with the exception of the lower trapezius showed EMG signs of fatigue, the most notable being the infraspinatus and deltoid muscles. In general, greater scapulothoracic motion and less glenohumeral motion was observed following muscle fatigue. Further studies are needed to determine what effects these changes have on the soft tissues and mechanics of the shoulder complex.     

Skin-fixed scapula trackers: a comparison of two dynamic methods across a range of calibration positions

The aim of this study was to establish the optimal methodology for skin-fixed measurement of the scapula during dynamic movement. This was achieved by comparing an optimally positioned Scapula Tracker device (ST) to a previously described palpation device, taken as the true measure of scapular kinematics. These measurements were compared across a range of calibration positions, including the use of multiple calibration positions for a single movement, in order to establish an optimal calibration approach. Ten subjects' scapular motion was measured using this ST and a previously described Acromial Method (AM). The two datasets were compared at a standard, an optimal and a 'multiple' calibration position, thus allowing a direct comparison between two common skin-fixed methods to track the bony kinematics of the scapula across different calibration positions. A comparison was also made with a bone-fixed technique from the literature. At both the standard and optimal calibration positions the ST was shown to be the more accurate measure of internal rotation and posterior tilt, particularly above 100° of humerothoracic elevation. The ST errors were found to be acceptable in relation to clinically important levels. Calibration positions have been shown to have a significant effect on the errors of both skin-fixed measurement techniques and therefore the importance of correct calibration is highlighted. It has thus been shown that a ST can be used to accurately quantify scapular motion when appropriately calibrated for the range of motion being measured.     

Kinesiotaping for scapular dyskinesis: The influence on scapular kinematics and on the activity of scapular stabilizing muscles

Scapular dyskinesis is observed in 61% of overhead athletes (Burn et al., 2016). For most of them, it remains asymptomatic. However, scapular dyskinesis is considered a risk factor for shoulder injury by some authors (Clarsen et al., 2014). The aim of this study is to explore the effectiveness of kinesiotaping in modifying scapular kinematics and peri-scapular muscle activity in dyskinetic athletes. The 3-dimensional position and orientation of the scapula as well as the activation of upper trapezius, lower trapezius and serratus anterior were recorded in twenty asymptomatic athletes during shoulder movements (flexion and abduction), in loaded and unloaded conditions and in three circumstances (standard, kinesiotaping 1, kinesiotaping 2). A significant decrease between 9 and 12% in upper trapezius activity was observed with kinesiotaping 1 and 2. Lower trapezius activity was slightly increased with kinesiotaping 1 while it was significantly decreased about 15–20% with kinesiotaping 2. No change was observed in serratus anterior activity, for either kinesiotaping 1 or 2. Considering scapular kinematics, both kinesiotaping 1 and 2 significantly increased posterior tilt and upward rotation. External rotation was decreased with kinesiotaping 2, in comparison to standard condition. Kinesiotaping, and especially taping 1, seems to be an effective method for changing periscapular muscle activity and scapular kinematics.     

Validity and reliability of shoulder kinematics in typically developing children and children with hemiplegic cerebral palsy

Shoulder motion has been mainly analysed in children based on thoraco-humeral (TH) joint kinematics, excluding the scapula-thoracic (ST) and gleno-humeral (GH) joints. In order to measure 3D scapulo-humeral motion using an optoelectronic system, we propose a protocol based on an acromion marker cluster (AMC), a functional method to determine the gleno-humeral rotation centre and different Euler sequences. This study investigated the validity of the AMC compared to the palpation of anatomical landmarks with a scapula locator, assessed the intra-session repeatability and the ability to discriminate differences of such a protocol in 10 typically developing children (TD) and 10 children with hemiplegic cerebral palsy (HCP) during 6 different tasks (flexion, abduction, horizontal abduction, hand to head, hand to controlateral shoulder and hand to back pocket). For both populations, the AMC method showed an overall Root Mean Square Error (RMSE) of 5.5°. The AMC method under-estimated the protraction/retraction of the scapula during abduction. The within-session reliability was good to excellent for all tasks except the hand to back pocket task. The YXY recommended Euler sequence for TH and GH joints resulted in gimbal lock for most of the tasks whereas the XZY sequence could be used for most of the tasks and most of the children.     

Adaptation of scapula lateral rotation after reverse anatomy shoulder replacement

Scapula motion is significant for support of the arm and stability of the shoulder. The effect of the humeral elevation on scapular kinematics has been well investigated for normal subjects, but there are limited published studies investigating adaptations after shoulder arthroplasty. Scapula kinematics was measured on 10 shoulders (eight subjects) with a reverse total joint replacement. The measurements were performed using an instrumented palpating technique. Every subject performed three simple tasks: abduction, elevation in scapula plane and forward flexion. Results indicate that, lateral scapula rotation was significantly increased (average of 24.42% over the normal rhythm) but the change was variable. Despite the variability, there is a clear trend correlating humeral performance with increased rotation (R2 0.829). There is clearly an adaptation in lateral scapula rotation in patients with shoulder joint replacement. The reason for this is unclear and may be related to joint pathology or to muscle adaptation following arthroplasty.