Digital fluoroscopic video assessment of glenohumeral migration: Static vs. Dynamic conditions

The purpose was to compare glenohumeral (GH) migration, during dynamic shoulder elevation and statically held positions using digital fluoroscopic videos (DFV). Thirty male volunteers (25±4 years) without right shoulder pathology were analyzed using DFV (30 Hz) during arm elevation in the scapular plane. DFV were obtained at the arm at side position, 45°, 90°, and 135° for static and dynamic conditions. GH migration was measured as the distance from the center of the humeral head migrated superiorly or inferiorly relative to the center of the glenoid fossa. Inter-rater reliability was considered good; ICC (2,3) ranged from 0.83 to 0.92. A main effect was revealed for contraction type (p=0.031), in which post-hoc t-tests revealed that humeral head was significantly more superior on the glenoid fossa during dynamic contraction. A main effect was also revealed for arm angle (p<0.001), in which post-hoc t-tests revealed significantly more superior humeral head positioning at 45°, 90°, and 135° when compared to arm at side (p<0.001), as well as at 90° compared to 45° (p=0.024). There was no interaction effect between angle and contraction type (p=0.400). Research utilizing static imaging may underestimate the amount of superior GH migration that occurs dynamically.     

Secondary motions of the shoulder during arm elevation in patients with shoulder tightness

An analysis of secondary shoulder motions (humeral rotation, humeral head anterior/posterior translation, scapular tipping, and scapular upward/downward rotation) in subjects with anterior/posterior shoulder tightness provides the opportunity to examine the role of tightness as a means of affecting shoulder motions. Subjects with shoulder tightness (anterior, n = 12; posterior, n = 12) elevated their arms in the scapular plane. Three replicated movements were performed to the maximum motions. Kinematics data were collected by FASTRAK 3D electromagnetic system. To determine if a significant difference of the secondary motions existed between anterior/posterior shoulder tightness, two-factor mixed ANOVA models with the repeated factor of elevation angle (five elevation angles) and the independent factor of group were calculated. The relationships between the self-reported functional scores (Flexilevel Scale of Shoulder Function, FLEX-SF) and abnormal shoulder kinematics were assessed. For humeral head anterior/posterior translation, the subjects with posterior tightness demonstrated anterior humeral head translation (10 mm, p = 0.019) compared to subjects with anterior tightness. The subjects with anterior tightness demonstrated less posterior tipping (2.2°, p = 0.045) compared to subjects with posterior tightness. The humeral anterior translation had moderate relationships with FLEX-SF scores (r = ?0.535) in subjects with posterior tightness. The scapular tipping had moderate relationships with FLEX-SF scores (r = 0.432) in subjects with anterior tightness. In conclusion, the secondary motions were different between subjects with anterior and posterior shoulder tightness. During arm elevation, less scapular posterior tipping and less posterior humeral head translation in subjects with anterior and posterior shoulder tightness, respectively, are significantly related to self-reported functional disability in these subjects.     

Three-dimensional comparison of static and dynamic scapular motion tracking techniques

The shoulder is complex and comprised of many moving parts. Accurately measuring shoulder rhythm is difficult. To classify shoulder rhythm and identify pathological movement, static measures have been the preferred method. However, dynamic measures are also used and can be less burdensome to obtain. The purpose of this paper was to determine how closely dynamic measures represent static measures using the same acromion marker cluster scapular tracking technique. Five shoulder angles were assessed for 24 participants using dynamic and static tracking techniques during humeral elevation in three planes (frontal, scapular, sagittal). ANOVAs were used to identify where significant differences existed for the factors of plane, elevation angle, and tracking technique (static, dynamic raising, dynamic lowering). All factors were significantly different for all shoulder angles (p < 0.001), except for elevation plane in scapulothoracic protraction/retraction (p = 0.955). Tracking techniques were influential (p < 0.001), but the grouped mean differences fell below a clinically relevant 5° benchmark. There was large variation in mean differences of the techniques across individuals. While population averages are similar, individual static and dynamic shoulder assessments may be different. Caution should be taken when dynamic shoulder assessments are performed on individuals, as they may not reflect those obtained in static scapular motion tracking.     

Adaptive glenoid bone remodeling simulation

Glenoid prosthesis loosening is the most common cause for revision total shoulder arthroplasty. Stress-induced bone remodeling may compromise long-term prosthesis fixation and significantly contribute to loosening. Realistic, robust analysis of bone-prosthesis constructs need to look beyond initial post-implantation mechanics provided by static finite element (FE) simulation. Adaptive bone remodeling simulations based on Wolff's law are needed for evaluating long-term glenoid prostheses fixation. The purpose of this study was to take a first step towards this goal and create and validate two-dimensional FE simulations, using the intact glenoid, for computing subject-specific adaptive glenoid remodeling. Two-dimensional glenoid FE models were created from scapulae computed tomography images. Two distinct processes, “element” and “node” simulations, used the forward-Euler method to compute bone remodeling. Initial bone density was homogeneous. Center and offset load combinations were iteratively applied. To validate the simulations we performed location-specific statistical comparisons between predicted and actual bone density, load combinations, and “element” and “node” processes. Visually and quantitatively “element” simulations produced better results (p>0.22), and correlation coefficients ranged 0.51–0.69 (p<0.001). Having met this initial work's goals, we expect subject-specific FE glenoid bone remodeling simulations together with static FE stress analyses to be effective tools for designing and evaluating glenoid prostheses.     

Biceps femoris and semitendinosus tendon/aponeurosis strain during passive and active (isometric) conditions

The purpose of this study was to quantify strain and elongation of the long head of the biceps femoris (BFlh) and the semitendinosus (ST) tendon/aponeurosis. Forty participants performed passive knee extension trials from 90° of knee flexion to full extension (0°) followed by ramp isometric contractions of the knee flexors at 0°, 45° and 90° of knee flexion. Two ultrasound probes were used to visualize the displacement of BFlh and ST tendon/aponeurosis. Three-way analysis of variance designs indicated that: (a) Tendon/aponeurosis (passive) elongation and strain were higher for the BFlh than the ST as the knee was passively extended (p < 0.05), (b) contraction at each angular position was accompanied by a smaller BFlh tendon/aponeurosis (active) strain and elongation than the ST at higher levels of effort (p < 0.05) and (c) combined (passive and active) strain was significantly higher for the BFlh than ST during ramp contraction at 0° but the opposite was observed for the 45° and 90° flexion angle tests (p < 0.05). Passive elongation of tendon/aponeurosis has an important effect on the tendon/aponeurosis behavior of the hamstrings and may contribute to a different loading of muscle fibers and tendinous tissue between BFlh and ST.     

The effects of biofeedback training for efficient activation of infraspinatus on proprioception and EMG activity during shoulder external rotation

The purpose of this study investigated which biofeedback (BF) training enables efficient activation of the infraspinatus muscle that affect joint position sense (JPS) and force sense (FS) of the shoulder joint. Twenty healthy males participated and performed three external rotation (ER) exercises under three randomly assigned training conditions: 1) non-biofeedback (NBF), 2) BF and 3) force biofeedback (FBF). Each exercise was performed at intervals of one week between training conditions. After performed the ER exercise under each training condition, the relative error (RE) was calculated at shoulder ER 45° and 80°, and then shoulder ER force were measured to determine the JPS error and FS error, respectively. Muscle activity of infraspinatus and posterior deltoid were measured and compared between training conditions. The RE of shoulder ER 45° and 80° were significantly lower under the FBF conditions than other training conditions (P < 0.05). The RE of shoulder ER force were also significantly lower under the FBF conditions compared to those under the other training conditions (P < 0.05). The activity of the infraspinatus muscle was significantly higher under the FBF conditions during all three ER exercises than other training conditions (p < 0.05). We suggest that BF trainings can be useful to improve the proprioception of shoulder joint as well as activation of infraspinatus muscle while performing the ER exercises.     

The effect of subscapularis muscle contraction on coaptation of anteroinferior glenohumeral ligament–labrum complex after Bankart repair

Facilitation of healing is important for the anteroinferior glenohumeral ligament–labrum complex (AIGHL-LC) after Bankart repair in shoulder dislocation. The purpose of this study was to investigate the effect of subscapularis muscle loading on contact area and contact pressure between the subscapularis and AIGHL-LC and between the glenoid bone and the AIGHL-LC following Bankart repair. Twenty-two fresh-frozen cadaveric shoulders were used. They were attached to a shoulder-positioning device to which a compression force was applied. Loads applied to the supraspinatus, infraspinatus, and teres minor tendons were held constant. The loads applied to the subscapularis tendon were set at 0, 10, 20, and 30 Newton (N). Contact pressure and area between the subscapularis and the AIGHL-LC were measured with the arm at 4 rotational positions: 60° and 30° internal, neutral, and 30° external. After the Bankart lesion was created, the contact area and pressure between the AIGHL-LC and glenoid bone were measured while Bankart repair was performed with or without loading of the subscapularis. The contact area and pressures with 10, 20, and 30 N of subscapularis loadings were significantly greater than with 0 N of subscapularis loading at 60° internal rotation and 30° external rotation (P < .05). After Bankart repair, contact area and pressure with subscapularis loading between the AIGHL-LC and glenoid bone were significantly greater than without subscapularis loading (P < .01). We conclude that isometric contraction exercises of the subscapularis might facilitate healing of the AIGHL-LC after Bankart repair.     

Finite element modelling of the glenohumeral capsule can help assess the tested region during a clinical exam

The objective of this research was to examine the efficacy of evaluating the region of the glenohumeral capsule being tested by clinical exams for shoulder instability using finite element (FE) models of the glenohumeral joint. Specifically, the regions of high capsule strain produced by glenohumeral joint positions commonly used during a clinical exam were identified. Kinematics that simulated a simple translation test with an anterior load at three external rotation angles were applied to a validated, subject-specific FE model of the glenohumeral joint at 60° of abduction. Maximum principal strains on the glenoid side of the inferior glenohumeral ligament (IGHL) were significantly higher than the maximum principal strains on the humeral side, for all three regions of the IGHL at 30° and 60° of external rotation. These regions of localised strain indicate that these joint positions might be used to test the glenoid side of the IGHL during this clinical exam, but are not useful for assessing the humeral side of the IGHL. The use of FE models will facilitate the search for additional joint positions that isolate high strains to other IGHL regions, including the humeral side of the IGHL.     

Shoulder labral pathomechanics with rotator cuff tears

Rotator cuff tears (RCTs), the most common injury of the shoulder, are often accompanied by tears in the superior glenoid labrum. We evaluated whether superior humeral head (HH) motion secondary to RCTs and loading of the long head of the biceps tendon (LHBT) are implicated in the development of this associated superior labral pathology. Additionally, we determined the efficacy of a finite element model (FEM) for predicting the mechanics of the labrum. The HH was oriented at 30° of glenohumeral abduction and neutral rotation with 50 N compressive force. Loads of 0 N or 22 N were applied to the LHBT. The HH was translated superiorly by 5 mm to simulate superior instability caused by RCTs. Superior displacement of the labrum was affected by translation of the HH (P<0.0001), position along the labrum (P<0.0001), and interaction between the location on the labrum and LHBT tension (P<0.05). The displacements predicted by the FEM were compared with mechanical tests from 6 cadaveric specimens and all were within 1 SD of the mean. A hyperelastic constitutive law for the labrum was a better predictor of labral behavior than the elastic law and insensitive to ±1 SD variations in material properties. Peak strains were observed at the glenoid–labrum interface below the LHBT attachment consistent with the common location of labral pathology. These results suggest that pathomechanics of the shoulder secondary to RCTs (e.g., superior HH translation) and LHBT loading play significant roles in the pathologic changes seen in the superior labrum.     

Comparison of glenohumeral joint kinematics between manual wheelchair tasks and implications on the subacromial space: A biplane fluoroscopy study

Scapula and humerus motion associated with common manual wheelchair tasks is hypothesized to reduce the subacromial space. However, previous work relied on either marker-based motion capture for kinematic measures, which is prone to skin-motion artifact; or ultrasound imaging for arthrokinematic measures, which are 2D and acquired in statically-held positions. The aim of this study was to use a fluoroscopy-based approach to accurately quantify glenohumeral kinematics during manual wheelchair use, and compare tasks for a subset of parameters theorized to be associated with mechanical impingement. Biplane images of the dominant shoulder were acquired during scapular plane elevation, propulsion, sideways lean, and weight-relief raise in ten manual wheelchair users with spinal cord injury. A computed tomography scan of the shoulder was obtained, and model-based tracking was used to quantify six-degree-of-freedom glenohumeral kinematics. Axial rotation and superior/inferior and anterior/posterior humeral head positions were characterized for full activity cycles and compared between tasks. The change in the subacromial space was also determined for the period of each task defined by maximal change in the aforementioned parameters. Propulsion, sideways lean, and weight-relief raise, but not scapular plane elevation, were marked by mean internal rotation (8.1°, 10.8°, 14.7°, −49.2° respectively). On average, the humeral head was most superiorly positioned during the weight-relief raise (1.6 ± 0.9 mm), but not significantly different from the sideways lean (0.8 ± 1.1 mm) (p = 0.191), and much of the task was characterized by inferior translation. Scaption was the only task without a defined period of superior translation on average. Pairwise comparisons revealed no significant differences between tasks for anterior/posterior position (task means range: 0.1–1.7 mm), but each task exhibited defined periods of anterior translation. There was not a consistent trend across tasks between internal rotation, superior translation, and anterior translation with reductions in the subacromial space. Further research is warranted to determine the likelihood of mechanical impingement during these tasks based on the measured task kinematics and reductions in the subacromial space.     

Jumping ability is related to change of direction ability in elite handball players

PurposeThis study investigated the relationship between vertical and horizontal jumping ability and change of direction (COD) to measure athletic performance in 51 elite male handball players.Scope.Countermovement jump (CMJ), peak power, and standing long jump (SLJ) were measured. Participants performed a 20-m sprint test (time measured at 5, 10, and 20 m) and a zigzag test (COD: 135°, 90°, and 45°). The COD deficit, an index of the time required for COD, was calculated. The correlations between CMJ height and zigzag test times were relatively large (at 135°, r =  − 0.607; at 90°, r =  − 0.594; at 45°, r =  − 0.613; p < 0.01), whereas those between CMJ height and COD deficit were moderate (at 135°, r =  − 0.399, p < 0.01; at 90°, r =  − 0.350, p < 0.05; at 45°, r =  − 0.323, p < 0.05). SLJ showed a negative moderate correlation with COD deficit (at 135°, r =  − 0.439, p < 0.01; at 90°, r =  − 0.469, p < 0.01; at 45°, r =  − 0.380, p < 0.01).ConclusionsThis study is the first to analyse SLJ ability and COD deficit parameters of handball players. We found that SLJ ability is moderately related to COD time and deficit; therefore, SLJ measurement may be a useful predictor of athletic performance.     

Sharper angle,higher risk? The effect of cutting angle on knee mechanics in invasion sport athletes

IntroductionCutting is an important skill in team-sports, but unfortunately is also related to non-contact ACL injuries. The purpose was to examine knee kinetics and kinematics at different cutting angles.Material and methods13 males and 16 females performed cuts at different angles (45°, 90°, 135° and 180°) at maximum speed. 3D kinematics and kinetics were collected. To determine differences across cutting angles (45°, 90°, 135° and 180°) and sex (female, male), a 4 × 2 repeated measures ANOVA was conducted followed by post hoc comparisons (Bonferroni) with alpha level set at α ≤ 0.05 a priori.ResultsAt all cutting angles, males showed greater knee flexion angles than females (p < 0.01). Also, where males performed all cutting angles with no differences in the amount of knee flexion −42.53° ± 8.95°, females decreased their knee flexion angle from −40.6° ± 7.2° when cutting at 45° to −36.81° ± 9.10° when cutting at 90°, 135° and 180° (p < 0.01). Knee flexion moment decreased for both sexes when cutting towards sharper angles (p < 0.05). At 90°, 135° and 180°, males showed greater knee valgus moments than females. For both sexes, knee valgus moment increased towards the sharper cutting angles and then stabilized compared to the 45° cutting angle (p < 0.01). Both females and males showed smaller vGRF when cutting to sharper angles (p < 0.01).ConclusionIt can be concluded that different cutting angles demand different knee kinematics and kinetics. Sharper cutting angles place the knee more at risk. However, females and males handle this differently, which has implications for injury prevention.     

Predictive mathematical modeling of knee static laxity after ACL reconstruction: in vivo analysis

Previous studies did not take into consideration such large variety of surgery variables which describe the performed anterior cruciate ligament (ACL) reconstruction and the interaction among them in the definition of postoperative outcome. Seventeen patients who underwent navigated Single Bundle plus Lateral Plasty ACL reconstruction were enrolled in the study. Static laxity was evaluated as the value of anterior/posterior displacement at 30° and at 90° of flexion, internal/external rotation at 30° and 90° of knee flexion, varus/valgus test at 0° and 30° of flexion. The evaluated surgical variables were analyzed through a multivariate analysis defining the following models: AP30_estimate, AP90_estimate, IE30_estimate, IE90_estimate, VV0_estimate, VV30_estimate. Surgical variables has been defined as the angles between the tibial tunnel and the three planes, the lengths of the tunnel and the relationship between native footprints and tunnels. An analogous characterization was performed for the femoral side. Performance and significance of the defined models have been quantified by the correlation ratio (η²) and the corresponding p-value (*p < 0.050). The analyzed models resulted to be statistically significant (p < 0.05) for prediction of postoperative static laxity values. The only exception was the AP90_estimate model. The η² ranged from 0.568 (IE90_estimate) to 0.995 (IE30_estimate). The orientation of the tibial tunnel resulted to be the most important surgical variable for the performed laxity estimation. Mathematical models for postoperative knee laxity is a useful tool to evaluate the effects of different surgical variables on the postoperative outcome.     

Translational stiffness of the replaced shoulder joint

Results after a total shoulder arthroplasty in rheumatoid patients are poor, indicated by loosening of especially the glenoid component, bad joint functionality and the possibility of a joint dislocation. The failure mechanisms behind this are multiple, including patient, surgical and design factors. These results must be improved. At present, the optimal geometrical prosthesis component design, focused on joint conformity and constraint, still has to be investigated.

Proper understanding of the effect of geometrical design parameters on the theoretical relationship between joint translations and joint forces may contribute to improved designs. The main objective of this study is to theoretically describe this relationship and to investigate the joint translational stiffness, which can be used to investigate the effect of design parameters on joint motion. Joint translational stiffness is the gradient of the subluxation force with respect to the humeral head displacement.

For this static analysis a potential field is introduced, as the result of a joint compressive force (muscle forces) and a subluxation force (external forces). The positive and negative stiffness during articulation inside and subluxation outside the glenoid cavity, lead to stable and unstable equilibrium joint positions, respectively. A most lateral position of the humeral head centre coincides with a zero subluxation force; at this position the humerus is dislocated and a restoring force is needed to relocate the humeral head.

Joint conformity and compression force influence the joint translational stiffness during articulation inside the glenoid cavity, whereas during articulating outside the glenoid cavity this is influenced by the joint compression force and humeral radius of curvature. The glenoid radius of curvature influences the contact point and, in combination with the glenoid superior–inferior chord length, it also influences the constraintness angle, which influences the maximum allowable subluxation load to prevent a joint dislocation. This constraintness angle together with the joint conformity also influences maximum joint translations before articulation outside the glenoid cavity. Furthermore, the sign of the joint translational stiffness determines the stability of shoulder motion, which is stable and unstable if this stiffness is positive and negative, respectively.     

Glenohumeral translation during active and passive elevation of the shoulder - a 3D open-MRI study

Despite its importance for the understanding of joint mechanics in healthy subjects and patients, there has been no three-dimensional (3D) in vivo data on the translation of the humeral head relative to the glenoid during abduction under controlled mechanical loading. The objective was therefore to analyze humeral head translation during passive and active elevation by applying an open MR technique and 3D digital postprocessing methods. Fifteen healthy volunteers were examined with an open MR system at different abduction positions under muscular relaxation (30-150 degrees of abduction) and during activity of shoulder muscles (60-120 degrees ). After segmentation and 3D reconstruction, the center of mass of the glenoid and the midpoint of the humeral head were determined and their relative position calculated. During passive elevation, the humeral head translated inferiorly from +1.58mm at 30 degrees to +0. 36mm at 150 degrees of abduction, and posteriorly from +1.55mm at 30 degrees to -0.07mm at 150 degrees of abduction. Muscular activity brought about significant changes in glenohumeral translation, the humeral head being in a more inferior position and more centered, particularly at 90 and 120 degrees of abduction (p<0.01). In anterior/posterior direction the humeral head was more centered at 60 and 90 degrees of abduction during muscle activity. The data demonstrate the importance of neuromuscular control in providing joint stability. The technique developed can also be used for investigating the effect of muscle dysfunction and their relevance on the mechanics of the shoulder joint.     

Spontaneous whole body rotations and classical dance expertise: How shoulder–hip coordination influences supporting leg displacements

The link between supporting leg stability and individual trunk strategies used during spontaneous whole-body rotations was studied according to visual and kinesthetic imagery styles for classical dancers and untrained female participants. Shoulders–hip angles in the horizontal plane and supporting leg (SL) displacements were analyzed with three-dimensional kinematic at the beginning and end of the four turns, identified according to their SL (left vs. right) and turn direction (clockwise, CW vs. counterclockwise, CCW). To begin a turn in CCW on left SL, all the participants turned shoulders before hips (?25° angle), p < 0.01. Untrained participants yielded the reverse (+30° angle) in CW – their non-preferred turn - whereas dancers maintained their trunk en bloc. In the turn slow down, in their preferred direction all the participants adopted en bloc behavior to avoid imbalance. Dancers kept this pattern in CCW but untrained participants separated shoulders and hips, p < 0.01; on left SL (+20° angle) hips finished before shoulders and on right SL (?25° angle), shoulders finished before hips. Both mental imagery styles and spatial context link reduction of shoulder–hip angle and stability of SL. Daily expertise, not only dance training, facilitates the en bloc shoulder–hip coordination to maintain equilibrium.     

Influence of muscle anatomical cross-sectional area on the moment arm length of the triceps brachii muscle at the elbow joint

The purpose of this study was to test the hypothesis that the musculotendon moment arm length is affected by the muscle anatomical cross-sectional area. The moment arm length of the triceps brachii (TB) muscle at 30°, 50°, 70°, 90°, 110° elbow flexion positions was measured in sagittal magnetic resonance images (MRI) of 18 subjects as the perpendicular distance between the center of the pulley of the humerus to the line through the center of the TB tendon. The moment arm increased as the elbow flexion angle decreased, from 1.74±0.13 cm at 110° to 2.39±0.14 cm at 30°. The maximal anatomical cross-sectional area of the TB muscle was significantly correlated with the moment arms at all joint positions (r=0.545–0.803, p<0.05). Furthermore, the circumference of the upper arm was also significantly correlated with the moment arms at all joint positions, except for 70° (r=0.504–0.702, p<0.05). These results indicate that the moment arm length of the TB muscle is affected by the muscle anatomical cross-sectional area.     

Osmotic dehydration of Kappaphycus alvarezii

The red alga Kappaphycus alvarezii has been reported to be a potential raw material for functional food due to its high content of soluble dietary fibre, mineral, omega-3 fatty acids as well as a substantial amount of essential amino acids. In order to benefit from these excellent nutritional properties, this project aimed to develop a high-value dehydrated snack from K. alvarezii using osmotic dehydration (OD) treatment prior to hot air-drying. A 3?×?3 factorial design with 50°, 60° and 70°Brix sucrose concentration as well as treatment temperatures of 30, 35 and 40 °C were used. In general, an increase in sucrose concentration and temperature promoted mass transfer. OD treatment using 70°Brix sucrose concentration at 40 °C caused case hardening of the seaweed that reduced the solid gain (p?<?0.05). Firmness of the seaweed increased with sucrose concentration and was not altered by temperature (p?<?0.05). The colour of the seaweed was not affected by OD treatment (p?>?0.05), but dehydrated seaweed became darker at high sugar concentration. Interaction effect between sucrose concentration and temperature was found to affect the water loss and solid gain of the OD treatment (p?<?0.05). The best sensory acceptable dehydrated seaweed was successfully identified. The final product contained high dietary fibre and very low Na/K ratio.     

Regional neuromuscular regulation within human rectus femoris muscle during gait

The spatial distribution pattern of neuromuscular activation within the human rectus femoris (RF) muscle was investigated during gait by multi-channel surface electromyography (surface EMG). Eleven healthy men walked on a treadmill with three gait speeds (4, 5, and 6 km/h) and gradients (0°, 12.5°, and 25°). The spatial distribution of surface EMG was tested by central locus activation (CLA), which is calculated from 2-D multi-channel surface EMG with 46 surface electrodes. For all conditions, CLA was around the middle regions during the swing-to-stance transition and moved in a proximal direction during the stance phase and stance-to-swing transition (p<0.05). CLA during the stance-to-swing transition and early swing phase significantly moved to proximal site with increasing gait speed (p<0.05). During the early stance and swing phases, with increasing grade, CLA significantly moved distally (p<0.05). These results suggest that the RF muscle is regionally activated during a gait cycle and is non-uniformly regulated longitudinally.     

The effects of taping on scapular kinematics and muscle performance in baseball players with shoulder impingement syndrome

PurposeThis study aimed to investigate the effect of elastic taping on kinematics, muscle activity and strength of the scapular region in baseball players with shoulder impingement.ScopeSeventeen baseball players with shoulder impingement were recruited from three amateur baseball teams. All subjects received both the elastic taping (Kinesio Tex^TM) and the placebo taping (3 M Micropore tape) over the lower trapezius muscle. We measured the 3-dimensional scapular motion, electromyographic (EMG) activities of the upper and lower trapezius, and the serratus anterior muscles during arm elevation. Strength of the lower trapezius was tested prior to and after each taping application. The results of the analyses of variance (ANOVA) with repeated measures showed that the elastic taping significantly increased the scapular posterior tilt at 30° and 60° during arm raising and increased the lower trapezius muscle activity in the 60–30° arm lowering phase (p < 0.05) in comparison to the placebo taping.ConclusionsThe elastic taping resulted in positive changes in scapular motion and muscle performance. The results supported its use as a treatment aid in managing shoulder impingement problems.