A Field-expedient Arm Care Screening Tool Can Identify Musculoskeletal Risk Factors in Baseball Players.

BACKGROUND: Preseason movement screening can identify modifiable risk factors, deterioration of function, and potential for injury in baseball players. Limited resources and time prevent high school baseball coaches from performing movement screens on their players. HYPOTHESIS: The arm care screen (ACS) will be highly sensitive to detecting musculoskeletal risk factors. STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 150 baseball players were independently scored on the ACS electronically by reviewing a video recording of each player's screening performance. Discriminability of the ACS was determined with a 2 × 2 contingency table dichotomizing musculoskeletal risk factors as present or absent based on a predetermined cutoff value and those who passed or failed the corresponding ACS subtest. RESULTS: High sensitivity was observed on the reciprocal shoulder mobility (0.89; 95% CI 0.81-0.94), 90/90 total body rotation (0.86; 95% CI 0.79-0.92), and lower body diagonal reach (0.85; 95% CI 0.78-0.91) tests of the ACS suggesting sufficient ability to identify musculoskeletal impairments and risk factors. CONCLUSION: The ACS is a simplistic screening tool that the coach can administer to discriminate between youth, high school, and college-level baseball players who possess musculoskeletal risk factors. The ACS subtests demonstrated high sensitivity for correctly identifying musculoskeletal risk factors common in baseball players and can be useful as a screening tool for baseball coaches developing arm care exercise programs. CLINICAL RELEVANCE: A field-expedient screen could provide coaches the ability to identify musculoskeletal risk factors that need to be addressed to minimize injury risk factors in a time-efficient manner.

Blood Flow Restriction Therapy: An Evidence-Based Approach to Postoperative Rehabilitation.

➢: Blood flow restriction therapy (BFRT) involves the application of a pneumatic tourniquet cuff to the proximal portion of the arm or leg. This restricts arterial blood flow while occluding venous return, which creates a hypoxic environment that induces many physiologic adaptations. ➢: BFRT is especially useful in postoperative rehabilitation because it produces muscular hypertrophy and strength gains without the need for heavy-load exercises that are contraindicated after surgery. ➢: Low-load resistance training with BFRT may be preferable to low-load or high-load training alone because it leads to comparable increases in strength and hypertrophy, without inducing muscular edema or increasing pain.

Lateral Patellar Dislocation: A Critical Review and Update of Evidence-Based Rehabilitation Practice Guidelines and Expected Outcomes.

¼: Nonoperative treatment of a lateral patellar dislocation produces favorable functional results, but as high as 35% of individuals experience recurrent dislocations. ¼: Medial patellofemoral ligament reconstruction is an effective treatment to prevent recurrent dislocations and yield excellent outcomes with a high rate of return to sport. ¼: Both nonoperative and postoperative rehabilitation should center on resolving pain and edema, restoring motion, and incorporating isolated and multijoint progressive strengthening exercises targeting the hip and knee. ¼: Prior to return to sports, both functional and isolated knee strength measurements should be used to determine leg symmetry strength and to utilize patient-reported outcome measures to assess the patient's perceived physical abilities and patellofemoral joint stability.

The Intra- and Inter-rater Reliability of an Arm Care Screening Tool in High School Baseball Coaches.

BACKGROUND: Preseason movement screening can identify modifiable risk factors, deterioration of function, and potential for injury in baseball players. Limited resources and time intensive testing procedures prevent high school coaches from accurately performing frequent movement screens on their players. PURPOSE: To establish the intra-rater and inter-rater reliability of a novel arm care screening tool based on the concepts of the Functional Movement Screen (FMS™) and Selective Functional Movement Assessment (SFMA™) in high school coaches. STUDY DESIGN: Methodological intra- and inter-rater reliability study. METHODS: Thirty-one male high school baseball players (15.9 years ± 1.06) were independently scored on the Arm Care Screen (ACS) by three examiners (two coaches, one physical therapist) in real-time and again seven days later by reviewing video recordings of each players' initial screening performance. Results from each examiner were compared within and between raters using Cohen's kappa and percent absolute agreement. RESULTS: Substantial to excellent intra-rater and inter-rater reliability were established among all raters for each component of the ACS. The mean Cohen's kappa coefficient for intra-rater reliability was 0.76 (95% confidence interval, 0.54-0.95) and percent absolute agreement ranged from 0.82-0.94 among all raters. Inter-rater reliability demonstrated a mean Cohen's kappa value of 0.89 (95% confidence interval, 0.77-0.99) while percent absolute agreement between raters ranged from 0.81-1.00. Intra- and inter-rater reliability did not differ between raters with various movement screening experience (p>0.05). CONCLUSIONS: High school baseball coaches with limited experience screening movement can reliably score all three components of the ACS in less than three minutes with minimal training. LEVEL OF EVIDENCE: Level 3, Reliability study.

Current Concepts in Arm Care Exercise Programs and Injury Risk Reduction in Adolescent Baseball Players: A Clinical Review.

CONTEXT: Awareness of important injury risk factors associated with excessive pitching volume has been highlighted in the literature, but injury rates remain high. Shoulder pain in baseball players is associated with various changes in musculoskeletal movements, which presents as measurable impairments throughout the kinetic chain. Baseball coaches and rehabilitation professionals have utilized exercise programs targeting strength and flexibility of the throwing arm to prevent injuries. The purpose of this review is to summarize the current evidence regarding the effectiveness of arm care exercise programs in reducing upper extremity injury rates in adolescent baseball players. EVIDENCE ACQUISITION: A search of electronic databases, including CINAHL with full text, MEDLINE, and SPORTDiscus was conducted to retrieve available articles in English from the years 2010 through 2020. The search terms injury prevention, exercise, and adolescent baseball were used. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: Improving shoulder internal rotation range of motion by stretching the posterior shoulder muscles daily was associated with a 36% risk reduction of shoulder and elbow injuries. Group-based arm care exercise programs that target multiple musculoskeletal impairments demonstrated an approximately 50% reduced risk of elbow injury. CONCLUSION: For adolescent baseball players, arm care injury prevention programs focusing on important musculoskeletal impairments are effective at reducing injury incidence rates. Multimodal injury prevention programs that improve multiple musculoskeletal impairments are more comprehensive and may result in better injury reduction than programs focusing on a singular impairment.

Comparison of Upper Extremity Function in Women With and Women Without a History of Breast Cancer.

BACKGROUND: Breast cancer treatments often result in upper extremity functional limitations in both the short and long term. Current evidence makes comparisons against a baseline or contralateral limb, but does not consider changes in function associated with aging. OBJECTIVE: The objective of this study was to compare upper extremity function between women treated for breast cancer more than 12 months in the past and women without cancer. DESIGN: This was an observational cross-sectional study. METHODS: Women who were diagnosed with breast cancer and had a mean post-surgical treatment time of 51 months (range = 12-336 months) were compared with women who did not have breast cancer (CTRL group). Self-reported upper extremity function using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and shoulder range of motion, strength, and muscular endurance were measured. Participants were divided into 3 groups: breast cancer involving the nondominant limb (BC-ND), breast cancer involving the dominant limb (BC-DOM), and CTRL. RESULTS: A total of 59 women in the CTRL group, 23 women in the BC-ND group, and 28 women in the BC-DOM group completed measures. Mean DASH scores in women with breast cancer were higher than those of women in the CTRL group, regardless of the limb on which cancer occurred (Cohen d = 1.13; 95% CI = 2.20 to 16.21) Range of motion for the BC-ND group was significantly less for flexion (Cohen d = 1.19, 95% CI = -13.08 to -0.11) and external rotation (Cohen d = 1.11, 95% CI = -18.62 to -1.98) compared with the CTRL group. Strength in the BC-ND group was 23% to 25% lower in the CTRL group for external (Cohen's d = 0.89, 95% CI = 0.09 to 0.12) and internal rotation (Cohen d = 0.92, 95% CI = 0.10 to 0.13). Endurance was not significantly different in the 3 groups. LIMITATIONS: Some participants had rehabilitation, which may have skewed results. The range of post-surgical treatment times was broad, making it difficult to determine when function returned. Muscular endurance measures demonstrated a ceiling effect and large variance, limiting the ability to distinguish differences among participants. These results may not be generalizable to the subset of women who were treated with lumpectomy, sentinel node biopsy, or chest wall radiation alone or who underwent a contralateral prophylactic mastectomy. CONCLUSION: In the long term, women with breast cancer have lower self-reported shoulder function than women without breast cancer. Motion and strength are lower among women who have experienced cancer on the nondominant limb.

MODIFYING STANCE ALTERS THE PEAK KNEE ADDUCTION MOMENT DURING A GOLF SWING.

BACKGROUND: The knee joint is one of the most frequently injured regions in the game of golf, and the loads experienced by the knee during the golf swing are typically greater than during other activities of daily living. Altering movement patterns is a common strategy that can be used to reduce loading on the knee joint but has received little attention during studies of the golf swing. The primary aim of this study was to examine the effect altering golf stance has on the lead limb peak external knee adduction moment. STUDY DESIGN: Laboratory based, quasi-experimental. METHODS: Twenty healthy participants were recruited for a 3-dimensional biomechanical analysis wherein participants hit three golf shots with a driver using the following stance conditions: self-selected, bilateral 0 º foot angle, bilateral 30 º foot angle, wide stance width, and narrow stance width. RESULTS: Both the 30 º foot angle (0.80 ± 0.51 Nm) and wide stance width (0.89 ± 0.49 Nm) conditions significantly decreased (p < 0.001) the lead limb peak external knee adduction moment compared to the self-selected (1.15 ± 0.58 Nm) golf stance. No significant differences (p = 0.109) in swing speed were found between any of the stance conditions. CONCLUSION: The externally rotated foot position and wider stance width decreased the lead limb peak external knee adduction moment without hindering swing speed. Modifying stance could be a viable option for golfers who wish to continue playing the sport at a high level, while reducing potentially detrimental loads at the knee joint.Levels of Evidence: 2b-Individual cohort study.

Reliability of Isometric and Eccentric Isokinetic Shoulder External Rotation.

CONTEXT: Shoulder external rotators are challenged eccentrically throughout the deceleration phase of throwing, which is thought to contribute to overuse injuries. To evaluate the effectiveness of intervention programs, as well as identifying deficits, reliable and responsive measures of isometric and eccentric shoulder external rotation are necessary. Previously, isometric measures have primarily tested a single position, and eccentric measures have not been found to have high reliability. OBJECTIVE: To examine the between-days reliability of multiple-angle isometric and dynamic eccentric isokinetic testing of shoulder external rotation. DESIGN: Repeated measures. PARTICIPANTS: 10 healthy subjects (age 30 ± 12 y, height 166 ± 13 cm, mass 72 ± 10 kg). MAIN OUTCOME MEASURES: Average isometric peak torque of shoulder external rotation at 7 angles was measured. From these values, the angle of isometric peak torque was calculated. Dynamic eccentric average peak torque, average total work, and average angle of peak torque were measured. RESULTS: Between-days reliability was high for average peak torque during isometric contractions at all angles (ICC ≥ .85), as it was for dynamic eccentric average peak torque (ICC ≥ .97). The estimated angle of isometric peak torque (ICC ≤ .65) was not highly reliable between days. The average angle of peak torque from the eccentric testing produced inconsistent results. Average total work of dynamic eccentric shoulder external rotation was found to be highly reliable between days (ICC ≥ .97). CONCLUSION: Aspects of force such as peak torque and total work in isometric and eccentric testing of the shoulder external-rotator muscles can be measured reliably between days and used to objectively evaluate shoulder strength and identify changes when they occur. Angle measurements of peak torque could provide insight into the mechanical properties of the posterior shoulder muscles but were found to be inconsistent between days.

Management of acute shoulder pain in an adolescent lacrosse athlete: a case report.

UNLABELLED: Acute onset of shoulder pain in adolescent athletes typically is related to trauma. The subject of this case report, a 13 year-old male, was injured when he collided with another athlete while his right arm was extended. He experienced immediate onset of significant right shoulder pain. Manual assessment in the emergency department revealed anterior tenderness and loss of function due to pain - most notably limitations in both active internal rotation and abduction. A plain film showed a radiographic density anterior to the humeral head but a donation site (where a bony avulsion may have occurred) was not delineated. Magnetic resonance imaging clearly identified a lesser tuberosity avulsion (thus the site of origin of the bony material) encompassing the insertion of the subscapularis muscle with retraction of approximately one centimeter. Open surgical repair (reduction and fixation) was performed with excellent results. LEVEL OF EVIDENCE: 5 (Single Case report).

Diagnostic imaging of the throwing athlete's shoulder.

UNLABELLED: The diagnostic capabilities of advanced imaging have increasingly enabled clinicians to delineate between structural alterations and injuries more efficiently than ever before. These impressive gains have unfortunately begun to provide a reliance on imaging at the loss of quality in the clinical examination. Ideally, imaging of the shoulder complex is performed to confirm the provisional diagnosis developed from the history and clinical exam rather than to create such. This clinical commentary will provide the framework for both basic and advanced uses of imaging as well as discussion of evolving modalities. LEVEL OF EVIDENCE: 5.

Glenohumeral instability and glenoid bone loss in a throwing athlete.

UNLABELLED: This case presents the challenges of management associated with a young throwing athlete presenting with a history of bilateral anterior shoulder instability. This athlete had multiple surgical interventions over a three-year period. The imaging modalities provided partial elucidation (at best) of the true picture of the pathology. This case report outlines the decision making process utilized to provide individualized care to a young throwing athlete with bilateral glenohumeral joint instability, recurrent dislocations, and resultant glenoid bone loss. LEVEL OF EVIDENCE: 5 (Single Case report).

Acute management concepts of the acromioclavicular joint: a case report.

UNLABELLED: Acromioclavicular injuries are quite common and approaches to early management of those that are described as a Type III are controversial. The Rockwood Type III classification implies complete disruption of the acromioclavicular and coracoclavicular ligaments, resulting in inferior positioning of the scapula and, thus, the glenohumeral complex while the clavicle appears more superiorly prominent. Clinical management can include surgical or conservative techniques. This case report outlines the decision making process related to this type of injury, as applied in the diagnosis and management of 61 year-old recreational athlete. LEVEL OF EVIDENCE: 5 (Single Case report).

Comparison of hip and knee strength and neuromuscular activity in subjects with and without patellofemoral pain syndrome.

PURPOSE/BACKGROUND: Historically, patellofemoral pain syndrome (PFPS) has been viewed exclusively as a knee problem. Recent findings have suggested an association between hip muscle weakness and PFPS. Altered neuromuscular activity about the hip also may contribute to PFPS; however, more limited data exist regarding this aspect. Most prior investigations also have not concurrently examined hip and knee strength and neuromuscular activity in this patient population. Additional knowledge regarding the interaction between hip and knee muscle function may enhance the current understanding of PFPS. The purpose of this study was to compare hip and knee strength and electromyographic (EMG) activity in subjects with and without PFPS. METHODS: Eighteen females with PFPS and 18 matched controls participated in this study. First, surface EMG electrodes were donned on the gluteus medius, vastus medialis, and vastus lateralis. Strength measures then were taken for the hip abductors, hip external rotators, and knee extensors. Subjects completed a standardized stair-stepping task to quantify muscle activation amplitudes during the loading response, single leg stance, and preswing intervals of stair descent as well as to determine muscle onset timing differences between the gluteus medius and vastii muscles and between the vastus medialis and vastus lateralis at the beginning of stair descent. RESULTS: Females with PFPS demonstrated less strength of the hip muscles. They also generated greater EMG activity of the gluteus medius and vastus medialis during the loading response and single leg stance intervals of stair descent. No differences existed with respect to onset activation of the vastus medialis and vastus lateralis. All subjects had a similar delay in gluteus medius onset activation relative to the vastii muscles. CONCLUSION: Rehabilitation should focus on quadriceps and hip strengthening. Although clinicians have incorporated gluteus medius exercise in rehabilitation programs, additional attention to the external rotators may be useful. LEVEL OF EVIDENCE: 4.

A pilot study of core stability and athletic performance: is there a relationship?

STUDY DESIGN: Correlation study OBJECTIVES: To objectively evaluate the relationship between core stability and athletic performance measures in male and female collegiate athletes. BACKGROUND: The relationship between core stability and athletic performance has yet to be quantified in the available literature. The current literature does not demonstrate whether or not core strength relates to functional performance. Questions remain regarding the most important components of core stability, the role of sport specificity, and the measurement of core stability in relation to athletic performance. METHODS: A sample of 35 volunteer student athletes from Asbury College (NAIA Division II) provided informed consent. Participants performed a series of five tests: double leg lowering (core stability test), the forty yard dash, the T-test, vertical jump, and a medicine ball throw. Participants performed three trials of each test in a randomized order. RESULTS: Correlations between the core stability test and each of the other four performance tests were determined using a General Linear Model. Medicine ball throw negatively correlated to the core stability test (r -0.389, p=0.023). Participants that performed better on the core stability test had a stronger negative correlation to the medicine ball throw (r =-0.527). Gender was the most strongly correlated variable to core strength, males with a mean measurement of double leg lowering of 47.43 degrees compared to females having a mean of 54.75 degrees. CONCLUSIONS: There appears to be a link between a core stability test and athletic performance tests; however, more research is needed to provide a definitive answer on the nature of this relationship. Ideally, specific performance tests will be able to better define and to examine relationships to core stability. Future studies should also seek to determine if there are specific sub-categories of core stability which are most important to allow for optimal training and performance for individual sports.

Reliability of electromyographic methods used for assessing hip and knee neuromuscular activity in females diagnosed with patellofemoral pain syndrome.

Patellofemoral pain syndrome (PFPS) is one of the most common, yet misunderstood, knee pathologies. PFPS is thought to result from abnormal patella tracking caused from altered neuromuscular control. Researchers have investigated neuromuscular influences from the gluteus medius (GM), vastus medialis (VM), and vastus lateralis (VL) but with inconsistent findings. A reason for these discrepancies may be from varying methodology. The purpose of this study was to determine the reliability of electromyographic (EMG) methods used to assess amplitudes and timing differences of the GM, VM, and VL in subjects with PFPS. Seven females with PFPS participated. GM, VM, and VL activity was assessed during the stance phase of a stair descent task on two separate occasions. Amplitudes during the different intervals of stance were recorded and expressed as a percent of each muscle's maximum voluntary isometric contraction. Muscle onsets at the beginning of stair descent were also determined. VM-GM, VL-GM, and VL-VM onset timing differences were quantified. Intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs) were calculated to assess between-day reliability. Most EMG measures had acceptable reliability (ICC(3,5)>or=0.70). Although some measures had moderate reliability (ICC<0.70), they had low SEMs, which suggested high measurement precision. These findings support using these methods for examining neuromuscular activity in subjects with PFPS.

Hip strength and hip and knee kinematics during stair descent in females with and without patellofemoral pain syndrome.

STUDY DESIGN: Cross-sectional. OBJECTIVE: To determine if females presenting with patellofemoral pain syndrome (PFPS) from no discernable cause other than overuse demonstrate hip weakness and increased hip internal rotation, hip adduction, and knee valgus during stair descent. BACKGROUND: Historically, PFPS has been viewed exclusively as a knee problem. Recent findings have indicated an association between hip weakness and PFPS. Researchers have hypothesized that patients who demonstrate hip weakness would exhibit increased hip internal rotation, hip adduction, and knee valgus during functional activities. To date, researchers have not simultaneously examined hip and knee strength and kinematics in subjects with PFPS to make this determination. METHODS AND MEASURES: Eighteen females diagnosed with PFPS and 18 matched controls participated. Strength measures were taken for the hip external rotators and hip abductors. Hip and knee kinematics were collected as subjects completed a standardized stair-stepping task. Independent t tests were used to determine between-group differences in strength and kinematics during stair descent. RESULTS: Subjects with PFPS generated 24% less hip external rotator (P = .002) and 26% less hip abductor (P =. 006) torque. No between-group differences (P > .05) were found for average hip and knee transverse and frontal plane angles during stair descent. CONCLUSION: Subjects with PFPS had significant hip weakness but did not demonstrate altered hip and knee kinematics as previously theorized. Additional investigations are needed to better understand the association between hip weakness and PFPS etiology.

Vastus medialis activation during knee extension exercises: evidence for exercise prescription.

CONTEXT: Knee extension exercise is an important part of knee rehabilitation. Clinicians prescribe non-weight bearing exercise initially and progress patients to weight bearing exercise once they can perform a straight leg raise (SLR). OBJECTIVE: Compare VM activation during a SLR and weight bearing exercises. DESIGN: One-way repeated measures design. SETTING: University Laboratory. SUBJECTS: Fifteen healthy subjects. INTERVENTION: One SLR exercise and 6 weight-bearing knee extension exercises. MAIN OUTCOME MEASURES: Electromyographic amplitudes for the VM expressed as a percent maximum voluntary isometric contraction. RESULTS: The SLR had greater activation than the single leg stance and bilateral squat exercises. The step-up and unilateral leg press exercises had the greatest activation. CONCLUSIONS: SLR performance can be an important indicator for exercise progression. These results provide foundational knowledge to assist clinicians with exercise prescription.

A comparison of select trunk muscle thickness change between subjects with low back pain classified in the treatment-based classification system and asymptomatic controls.

STUDY DESIGN: Cross-sectional descriptive. OBJECTIVES: To investigate if muscle thickness change, as measured with rehabilitative ultrasound imaging (RUSI), is different across subgroups of patients with low back pain (LBP), classified in the Treatment-Based Classification (TBC) system, when compared to controls. BACKGROUND: Researchers have demonstrated that subgroups of patients with LBP exist and respond differently to treatment, challenging the assertion that LBP is "nonspecific." The TBC system uses 4 categories (stabilization, mobilization, direction specific exercise, or traction) to subgroup patients. Recently, researchers have demonstrated impairments of the transverse abdominis (TrA) and lumbar multifidus (LM) in those with LBP, regardless of classification. Although distinct differences in impairments have been identified between subgroups, TrA and LM impairments have not been studied and may be present across categories of the TBC system. METHODS AND MEASURES: RUSI was utilized to measure percent thickness change from rest to contracted state during a voluntary task of the TrA and during an upper extremity task known to activate the LM in 56 subjects classified in the TBC system and 20 controls. RESULTS: During the prone upper extremity lifting task with a hand weight, there was a significant group difference for the LM at L4-L5 (P = .03) and at L5-S1 (P = .04), and during volitional activation for the TrA (P < .01). Post hoc testing revealed the differences were between controls and both the direction specific and stabilization categories at the L4-L5 level, between control and direction specific category for the L5-S1 level, and between controls and all 3 categories for the TrA. CONCLUSION: Deficits in the ability to generate muscle thickness changes in the TrA and LM occurred across categories of the TBC system. Intervention studies should be performed to determine if intervention can correct these deficits and if deficit corrections are related to outcomes.

Effect of orthoses on postural stability in asymptomatic subjects with rearfoot malalignment during a 6-week acclimation period.

OBJECTIVE: To determine the effect of custom-fitted orthoses on postural sway over a 6-week acclimation period. DESIGN: Repeated-measures analysis of variance on postural sway measures with factors being group (control, malaligned), time (initial, 2 wk, 4 wk, 6 wk postintervention), and condition (with orthoses, without orthoses). For single-limb stance, side (right, left) was analyzed to determine bilateral differences. SETTING: Biodynamics laboratory. PARTICIPANTS: Twenty-one subjects, 11 asymptomatic with rearfoot malalignment and 10 asymptomatic with normal rearfoot alignment. INTERVENTIONS: Orthoses were prescribed and worn for 6 weeks. Balance testing was performed on 4 different dates with each subject tested in both orthotic conditions. Postural control was measured with three 10-second eyes-closed trials for single-limb stance, one 20-second eyes-closed bilateral stance with the platform moving, and one 20-second eyes-open bilateral stance with the platform and surroundings moving. MAIN OUTCOME MEASURES: Sway velocity (in deg/s) for single-limb stance and equilibrium score for bilateral stance. RESULTS: Postural sway measures were significantly decreased during single-limb testing with orthoses versus without orthoses, regardless of group. The orthotic intervention significantly improved bilateral stance equilibrium score in the malaligned group at weeks 2, 4, and 6 when compared with measures at the initial week. Equilibrium score of the malaligned group with orthoses at initial week was significantly lower (worse) than the control group with orthoses at initial week; however, these results were not repeated during measurements taken at weeks 2, 4, or 6. CONCLUSIONS: The application of orthoses decreased sway velocity for single-limb stance, improving postural stability regardless of group when visual feedback was removed. During bilateral stance, postural stability was initially worse for the malaligned group with and without orthoses when compared with the control group; however, improvements were seen by week 2 and continued throughout the remainder of testing. Clinically, the application of orthoses appears to improve postural control in people with rearfoot malalignment, particularly when vision is removed.

EMG analysis of shoulder muscle fatigue during resisted isometric shoulder elevation.

The purpose of this study was to determine if a difference existed in the rate of fatigue of select shoulder muscles during isometric shoulder elevation and if the measured rate of fatigue was consistent from day to day. Shoulder muscle fatigue has been associated with alterations in joint mechanics and possibly contributes to shoulder dysfunction. While research exists, there is limited information on an objective and reliable measure of shoulder fatigue. Sixteen asymptomatic subjects were evaluated. The subjects held a weight equivalent to 60% of his/her Maximum Voluntary Isometric Contraction (MVIC) while elevating in the scapular plane. Surface electrodes were applied to collect electromyographic activity from the upper trapezius, middle deltoid, serratus anterior, and lower trapezius muscles while the arm was held at 90 degrees elevation. Data collection ceased when the subject was no longer able to maintain 90 degrees of elevation. The subject then rested and a second trial performed. One week later, the two-trial procedure was repeated. A significant interaction of trial x day x muscle was found for the rate of fatigue. Post hoc analysis revealed that the rate of fatigue of the middle deltoid was significantly greater than the other muscles tested. The intraday reliability was good for all muscles but interday reliability was poor except for the middle deltoid. This study suggests that the middle deltoid appears to fatigue faster than the other shoulder muscles tested at the selected level of shoulder elevation. This should be considered in designing a rehabilitation program to develop a sequence that does not overly fatigue the middle deltoid.