Effect of a Novel Training Program in Patients With Chronic Shoulder Pain Based on Implicit Motor Learning: Pilot and Feasibility Study.

Background: Implicit motor learning has been shown to be effective for learning sports-related motor skills. It facilitates automaticity of movements and thereby improves performance in multitasking and high-pressure environments. Motor learning to develop motor skills and neuroplastic capacities is not sufficiently incorporated in musculoskeletal rehabilitation. Especially in patients with chronic pain conditions like shoulder pain this approach might benefit over traditional exercise programs. Purpose/hypothesis: The aim of this study was to investigate the feasibility and clinical outcome of a new implicit motor learning exercise program in a group of patients with chronic shoulder pain. Study design: Pilot and feasibility cohort study. Methods: Twenty-six patients with chronic shoulder pain performed a 6-week home exercise program with weekly remote follow up by a physiotherapist. The program comprised five exercises designed to challenge overall body balance, simultaneously engaging the upper limbs in a range of reaching tasks. The tasks included reaching above the head, at and below waist level, in various directions. No instructions on correct performance were provided to foster external focus. Feasibility was assessed by (1) recruitment rate, (2) follow up rate, (3) subjective experience, (4) self-reported adverse events and (5) self-reported adherence of subjects. Clinical effects of the program were assessed with (1) the Shoulder Pain and Disability Index (SPADI), (2) the Auto-Constant score, (3) the numeric rating scale (NRS) at rest and at night, (4) the patient specific functional scale (PSFS), (5) the avoidance endurance questionnaire (AEQ), (6) patient acceptable symptom state (PASS) and (7) a global rating of change (GROC). Results: The study protocol was feasible in terms of follow up rate (16w for 28 patients), exercise adherence (77.1%± 29.41), and adverse events (no serious, 5 light adverse events). Statistically significant improvements were observed for SPADI (p<0.001), NRS at rest (p=0.033), at night (p=0.29), PSFS (p<0.001) and PASS (p<0.001) after only six weeks training. Conclusion: This study reveals promising results of another way of looking at exercise for patients with chronic shoulder pain. Both feasibility and clinical effects of the program on pain and function was acceptable. Future studies should incorporate a control group, provide longer follow up and include objective measurements. Level of evidence: 2b.

Radioactive iodine treatment for Graves' hyperthyroidism: incidence of Graves orbitopathy.

PURPOSE: There are limited recent data on the effect of radioactive iodine (RAI) for Graves' disease on Graves' orbitopathy (GO) development or reactivation. This audit investigates the GO incidence in patients with Graves' disease after RAI treatment, and explores risk factors present, and steroid prophylaxis use. METHODS: A retrospective audit of Graves' disease patients treated with RAI over a 5-year period. Data collected: smoking status, thyroid-stimulating hormone receptor antibody (TRAb) status, GO history, Graves' disease duration, eye features pre- and post-treatment, prophylactic corticosteroids, RAI dose given, post-RAI thyroid status, duration until hypothyroid. RESULTS: One hundred one patients were included, with a median Graves' disease duration 36 months. 34/101 (33.7%) were active/ex-smokers, 86/101 (85.1%) were TRAb-positive, 11/101 (10.9%) had a GO history; 32 (31.7%) had eye features present. Median RAI dose given was 596MBq. 8/101 (7.9%) patients received prophylactic corticosteroid; 89/101 (88.1%) achieved hypothyroid state in the year after RAI. GO developed in 5/101 (5.0%), of which 4/5 (80%) were de novo in high-risk individuals who did not receive steroids. One was a GO reactivation despite steroids. Two required intravenous steroids with/without orbital radiotherapy, one completed oral steroid taper; the remainder were treated conservatively. CONCLUSION: Our cohort had a lower GO incidence in patients with Graves' disease receiving RAI, with majority arising de novo . It is essential that all patients are assessed for Graves orbitopathy risk factors and counselled adequately prior to RAI. The decision to initiate steroids should be undertaken in a multi-disciplinary setting involving endocrinologists and ophthalmologists.

Kinetic chain revisited: consensus expert opinion on terminology, clinical reasoning, examination, and treatment in people with shoulder pain.

BACKGROUND: The purpose of this study was to reach consensus on the most appropriate terminology and issues related to clinical reasoning, examination, and treatment of the kinetic chain (KC) in people with shoulder pain among an international panel of experts. METHODS: A 3-round Delphi study that involved an international panel of experts with extensive clinical, teaching, and research experience in the study topic was conducted. A search equation of terms related to the KC in Web of Science and a manual search were used to find the experts. Participants were asked to rate items across 5 different domains (terminology, clinical reasoning, subjective examination, physical examination, and treatment) using a 5-point Likert-type scale. An Aiken coefficient of validity (V) ≥0.7 was considered indicative of group consensus. RESULTS: The participation rate was 30.2% (n = 16), whereas the retention rate was high throughout the 3 rounds (100%, 93.8%, and 100%). A total of 15 experts from different fields and countries completed the study. After the 3 rounds, consensus was reached on 102 items: 3 items were included in the "terminology" domain; 17 items, in the "rationale and clinical reasoning" domain; 11 items, in the "subjective examination" domain; 44 items, in the "physical examination" domain; and 27 items, in the "treatment" domain. Terminology was the domain with the highest level of agreement, with 2 items achieving an Aiken V of 0.93, whereas the domains of physical examination and treatment of the KC were the 2 areas with less consensus. Together with the terminology items, 1 item from the treatment domain and 2 items from the rationale and clinical reasoning domain reached the highest level of agreement (V = 0.93 and V = 0.92, respectively). CONCLUSION: This study defined a list of 102 items across 5 different domains (terminology, rationale and clinical reasoning, subjective examination, physical examination, and treatment) regarding the KC in people with shoulder pain. The term "KC" was preferred and a agreement on a definition of this concept was reached. Dysfunction of a segment in the chain (ie, weak link) was agreed to result in altered performance or injury to distal segments. Experts considered it important to assess and treat the KC in particular in throwing or overhead athletes and agreed that no one-size-fits-all approach exists when implementing shoulder KC exercises within the rehabilitation process. Further research is now required to determine the validity of the identified items.

Evidence for taping in overhead athlete shoulders: a systematic review.

Taping is a popular approach and is often used as part of a multifactorial injury prevention programme for athletes. The aim of this study was to evaluate the current literature regarding the effects of shoulder taping in overhead athletes. Literature search was performed related to rotational range of motion (RoM), posterior shoulder tightness (PST), kinematics, muscular activity, acromiohumeral distance (AHD), proprioception, strength, and performance. Twenty studies were eligible. The majority of the applied taping methods were scapular and humeral head repositioning taping. Across all studies, there was limited to moderate evidence in favour of taping in overhead athletes with regard to rotational RoM, AHD, proprioception, and altering scapular kinematics, while taping did not enhance PST, muscular activity, shoulder strength, and performance. Therefore, the current evidence showed taping can alter some of the investigated factors that may have a therapeutic or preventive role. However, in the management of the athlete shoulder, taping-only approaches should not be focused on, and taping can be integrated in a more comprehensive approach for the overhead athletes.

Scapulothoracic muscle activity during kinetic chain variations of a prone elevation exercise.

BACKGROUND: Scapular rehabilitation exercises should target appropriate muscles. Recently, adding external rotation resistance to scapular exercises has gained interest. Moreover, clinical experts advise kinetic chain integration into shoulder rehabilitation exercises. OBJECTIVE: To investigate scapular muscle activity during kinetic chain variations of a prone elevation exercise. METHODS: Activity of the upper (UT), middle (MT), and lower (LT) trapezius and serratus anterior (SA) muscles was determined with surface electromyography (EMG) in 31 asymptomatic participants during six prone elevation exercise variations. Variation was created by adding external rotation resistance, adding trunk extension, or changing exercise position (prone on a Swiss ball with knees or feet supported, or prone on a physiotable). All data were normalized as a percentage of maximal voluntary isometric contraction (% MVIC). For each muscle, a Friedman's ANOVA was conducted to analyse statistical differences in EMG signal intensity between exercises. RESULTS: The LT was moderately (42 - 48% MVIC) and MT highly (63 - 66% MVIC) activated during all exercise variations. No significant differences between exercises for these muscles could be detected. Adding external rotation to a prone elevation exercise decreased UT activity while adding trunk extension increased UT activity. Altering exercise position had no influence on scapular muscle activity except increased UT activity when lying prone on a physiotable with trunk extension. CONCLUSION: Prone elevation exercises are appropriate for facilitating LT and MT activity. Adding external rotation inhibits UT activity while UT facilitation could be achieved when adding trunk extension.

Does verbal and tactile feedback change EMG activity in shoulder girdle and trunk muscles during plyometric exercise in overhead athletes with and without shoulder pain?

OBJECTIVES: To investigate if there is a difference in muscle activity for overhead athletes before and after an intervention with correction of both core and scapula compared to no intervention and is there a difference between overhead athletes with or without shoulder pain. DESIGN: Controlled laboratory EMG study including intervention. SETTING: University EMG laboratory. PARTICIPANTS: Sixty overhead athletes, 30 with shoulder pain and 30 healthy controls were included performing plyometric rotational shoulder exercise. MAIN OUTCOMES: Half of the participants received an intervention the other half were controls with no intervention. EMG muscle activity from 10 scapular, thoraco-humeral and trunk muscles were measured. RESULTS: There were no significant differences in muscle activation levels between the groups with or without intervention. For the shoulder pain group, there were significant lower activity in Upper Trapezius when repeating the exercise. The shoulder pain group had significant higher activity in Pectoralis Major compared to the Healthy Control group. CONCLUSIONS: Most differences were found between the pre- and post-test. Repetition of the exercise seems to be more important than verbal and tactile instructions. Comparing the shoulder pain group with the healthy controls confirms previous findings that, pain patients recruit muscles differently from healthy persons.

Does the Activity in Scapular Muscles During Plyometric Exercises Change When the Kinetic Chain Is Challenged?-An EMG Study.

ABSTRACT: Werin, MB, Maenhout, AG, Icket, J, Jacxsens, N, Kempkes, E, and Cools, AM. Does the activity in scapular muscles during plyometric exercises change when the kinetic chain is challenged?-An EMG study. J Strength Cond Res 36(7): 1793-1800, 2022-Plyometric exercises for the shoulder are used in rehabilitation and in workout regime when the sport demands high speed power training. The aim of this clinical laboratory electromyography (EMG) study was to determine whether scapular muscle performance differs during plyometric shoulder exercises when changing the demand on the kinetic chain. Thirty healthy overhead athletes, with a mean age of 22.7 years (±2.2), performed 6 exercises, with both a low and a high demand on the kinetic chain, in prone, side and standing in positions. The EMG activity of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) on the tested side and bilateral of gluteus maximus (GM) and abdominal oblique externus (OE) was registered with wireless surface EMG. Intermuscular muscle ratios UT/SA, UT/MT, and UT/LT were also calculated. The level of significance set for the study was alpha = 0.05. The muscle ratio UT/SA was significantly lower (p < 0.05) when high demand on the kinetic chain compared with low. SA muscle activity showed significantly (<0.001) higher values in the prone position with high demand on the kinetic chain compared with low. All 3 trapezius muscle parts had significantly higher values (p < 0.001) in the prone compared with side and standing positions. The GM and OE showed significantly higher (p ≤ 0.01) activity in positions more demanding for the kinetic chain. When composing a strengthening or a rehabilitation program for athletes, the knowledge of how scapular and trunk muscles interact can be used to amplify the strengthening effect.

Comparison of 90Y SIRT predicted and delivered absorbed doses using a PSF conversion method.

PURPOSE: The aims of this study were to develop and apply a method to correct for the differences in partial volume effects of pre-therapy Technetium-99 m (99mTc)-MAA SPECT and post-therapy Yttrium-90 (90Y) bremsstrahlung SPECT imaging in selective internal radiation therapy, and to use this method to improve quantitative comparison of predicted and delivered 90Y absorbed doses. METHODS: The spatial resolution of 99mTc SPECT data was converted to that of 90Y SPECT data using a function calculated from 99mTc and 90Y point spread functions. This resolution conversion method (RCM) was first applied to 99mTc and 90Y SPECT phantom data to validate the method, and then to clinical data to assess the power of 99mTc SPECT imaging to predict the therapeutic absorbed dose. RESULTS: The maximum difference between absorbed doses to phantom spheres was 178%. This was reduced to 27% after the RCM was applied. The clinical data demonstrated differences within 38% for mean absorbed doses delivered to the normal liver, which were reduced to 20% after application of the RCM. Analysis of clinical data showed that therapeutic absorbed doses delivered to tumours greater than 100 cm3 were predicted to within 52%, although there were differences of up to 210% for smaller tumours, even after the RCM was applied. CONCLUSIONS: The RCM was successfully verified using phantom data. Analysis of the clinical data established that the 99mTc pre-therapy imaging was predictive of the 90Y absorbed dose to the normal liver to within 20%, but had poor predictability for tumours smaller than 100 cm3.

The challenge of the sporting shoulder: From injury prevention through sport-specific rehabilitation toward return to play.

Shoulder injuries and sports-related shoulder pain are substantial burdens for athletes performing a shoulder loading sport. The burden of shoulder problems in the athletic population highlights the need for prevention strategies, effective rehabilitation programs, and a individually based return-to-play (RTP) decision. The purpose of this clinical commentary is to discuss each of these 3 challenges in the sporting shoulder, to assist the professional in: (1) preventing injury; (2) providing evidence-based practice rehabilitation and; (3) to guide the athlete toward RTP. The challenges for injury prevention may be found in the search for (the interaction between) relevant risk factors, develop valid screening tests, and implement feasible injury prevention programmes with maximal adherence from the athletes. Combined analytical and functional testing seems mandatory screening an athlete's performance. Many questions arise when rehabilitating the overhead athlete, from exercise selection, over the value of stretching, toward kinetic chain implementation and progression to high performance training. Evidence-based practice should be driven by the available research, clinical expertise and the patient's expectations. Deciding when to return to sport after a shoulder injury is complex and multifactorial. The main concern in the RTP decision is to minimize the risk of re-injury. In the absence of a "gold standard", clinicians may rely on general guidelines, based on expert opinion, regarding cutoff values for normal range of motion, strength and function, with attention to risk tolerance and load management.

Electromyographic analysis of selected shoulder muscles during a series of exercises commonly used in patients with symptomatic degenerative rotator cuff tears.

BACKGROUND: In the nonoperative treatment of degenerative rotator cuff (RC) tears, exercise therapy is advocated. Exercises focusing on strengthening the anterior deltoid (AD) and the scapular muscles are proposed to compensate for RC dysfunction. However, the amount of electromyographic (EMG) activity in these muscles during these exercises remains unclear. Moreover, it is unknown whether muscle activity levels during these exercises alter with increasing age. Therefore, the purpose of this study was to evaluate EMG activity in the deltoid and scapular muscles during 2 series of commonly used shoulder rehabilitation exercises and assess possible age-related changes in muscle activity. METHODS: Fifty-five healthy participants (aged 18-60 years) participated in this study. Surface EMG activity was measured in 8 shoulder girdle muscles during a progression of a closed chain elevation program (bench and wall slides) and during a progression of previously published AD exercises. In addition, muscle activity was compared between 3 age categories (18-32 years, 33-46 years, and 47-60 years). RESULTS: The proposed progressions exhibited increasing activity from <10% of maximal voluntary isometric contraction to >20% of maximal voluntary isometric contraction for the AD for both exercise programs and for the middle deltoid, upper trapezius, and middle trapezius during the closed chain elevation exercises. Activity levels in the other muscles remained <20% throughout the progression. Age-related analysis revealed increased activity in the AD, infraspinatus, and middle trapezius and decreased lower trapezius activity during the bench and wall slides. No age-related changes were noted for the AD exercises. CONCLUSION: These findings may assist the clinician in prescribing appropriate progressive exercise programs for patients with symptomatic RC tears.

Incorporation of the Kinetic Chain Into Shoulder-Elevation Exercises: Does It Affect Scapular Muscle Activity?

CONTEXT: Scapular rehabilitation exercises should focus on selective activation of weaker muscles and minimal activation of hyperactive muscles. For rehabilitation of overhead athletes, single-plane open chain exercises below 90° of shoulder elevation are often recommended. Moreover, incorporating the kinetic chain in shoulder rehabilitation exercises is advised and has been suggested to influence scapular muscle activity levels. OBJECTIVE: To study the influence of kinetic chain incorporation during 5 variations of a shoulder-elevation exercise on scapular muscle activity. DESIGN: Cross-sectional study. SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty-one asymptomatic participants (15 men, 16 women). MAIN OUTCOME MEASURE(S): The electromyographic activity of the upper (UT), middle (MT), and lower (LT) trapezius, and serratus anterior was determined during 5 variations of bilateral elevation with external rotation: (1) open-hand position (reference exercise), (2) closed-hand position, (3) dynamic bipedal squat, (4) static unipedal squat, and (5) dynamic unipedal squat on the contralateral leg. All data were normalized as a percentage of maximal voluntary isometric contraction (MVIC). RESULTS: A closed-hand position (exercise 2) instead of an open-hand position (exercise 1) resulted in lower MT (mean difference = 3.44% MVIC) and LT (mean difference = 7.76% MVIC) activity. Incorporating the lower limb (exercises 3-5) increased UT activity when compared with exercise 1 (mean differences = 3.67, 2.68, 5.02% MVIC, respectively), which in general resulted in increased UT : MT ratios. Additionally, LT activity decreased when a dynamic unipedal squat was added (mean difference: 4.90% MVIC). For the serratus anterior, the greatest activity occurred during elevation in a static unipedal squat position (exercise 4, 22.90% MVIC). CONCLUSIONS: Incorporating the kinetic chain during shoulder-elevation exercises influenced scapular muscle activity and ratios. In particular, incorporating the lower limb resulted in more UT activity, whereas the open-hand position increased MT and LT activity.

Muscle recruitment during plyometric exercises in overhead athletes with and without shoulder pain.

OBJECTIVES: To investigate if there is a difference in muscle activity patterns during high load plyometric shoulder exercises between overhead athletes with and without shoulder pain. DESIGN: Controlled laboratory EMG study. SETTING: University EMG Laboratory. PARTICIPANTS: Sixty overhead athletes, 30 with shoulder pain and 30 healthy controls were included. MAIN OUTCOME MEASURES: The EMG activity of Upper Trapezius (UT), Middle Trapezius (MT), Lower Trapezius (LT), Serratus Anterior (SA), Latissimus Dorsi (LD) and Pectoralis Major (PM) on the tested side and bilateral on Abdominal Obliques Externus (OE) muscles was registered with wireless surface EMG during 3 rotational plyometric shoulder exercises in 3 positions, prone, sidelying and standing. RESULTS: A significant higher muscle activity was found in the shoulder pain group for MT together with an overall significant higher activity in the thoraco-humeral and abdominal muscles compared to healthy controls. CONCLUSIONS: When rehabilitating the overhead athlete with shoulder pain, shoulder muscles together with both thoraco-humeral and abdominal muscles need to be engaged.

The relationship between quality of life in a nursing home and personal, organizational, activity-related factors and social satisfaction: a cross-sectional study with multiple linear regression analyses.

Objectives: This study aimed to investigate quality of life in nursing home residents and the relationship with personal, organizational, activity-related factors and social satisfaction.Methods: In a cross-sectional survey study in 73 nursing homes in Flanders, Belgium, 171 cognitively healthy residents were randomly recruited (mean age 85.40 years [±5.88]; 27% men, 73% women). Quality of life, as the dependent/response variable, was measured using anamnestic comparative self-assessment (range -5 to +5). Multiple linear regression (forward stepwise selection) was used (1) to investigate which factors were significantly related to nursing home residents' quality of life and (2) to model the relationship between the variables by fitting a linear equation to the observed data.Results: Nursing home residents reported a quality of life score of 2.12 (±2.16). Mood, self-perceived health status, social satisfaction and educational level were withheld as significant predictors of the anamnestic comparative self-assessment score (p < 0.001), explaining 38.1% of the variance in quality of life.Conclusions: Results suggest that a higher quality of life in nursing homes can be pursued by strategies to prevent depression and to improve nursing home residents' subjective perception of health (e.g. offering good care) and social network. It is recommended that nursing homes prepare for future generations, who will be more educated.

Quantifying acromiohumeral distance in elite male field hockey players compared to a non-athletic population.

BACKGROUND: Shoulders of elite field hockey players are loaded continuously during play. Frequent high shoulder loading is known to influence certain shoulder variables, such as acromiohumeral distance. However, the influence of elite field hockey play on acromiohumeral distance is not examined yet. OBJECTIVE: To examine the acromiohumeral distance in elite male field hockey players compared to a non-athletic control group. DESIGN: Cross-sectional study. METHODS: Fifty male participants were included; 25 elite field hockey players (age: 24.0±2.72 years; weight: 77.2±5.29kg; height; 180.5±5.37cm) and 25 age- and gender matched non-athletes (23.0±2.29 years; weight: 75.7±9.53kg; height: 181.8±5.52cm). A Telemed-Colormaster-128 EXT-IZ device was used to bilaterally obtain ultrasound acromiohumeral distance images at 3 different angles of shoulder abduction in the frontal plane. RESULTS: Field hockey players showed a bilateral larger acromiohumeral distance at 45° (mean difference: 1.46mm [95% CI 0.46; 2.46]; p=0.005) and 60° (mean difference: 1.07mm [95% CI 0.21; 1.93]; p=0.016) compared to controls. In both groups, a significant but clinically less relevant, side difference was established for the acromiohumeral distance at 60° (mean difference: 0.79mm [95% CI 0.21; 1.34]; p=0.009). CONCLUSION: With active shoulder abduction, elite field hockey players show a larger acromiohumeral distance in comparison to non-athletic participants. This may be a protective sport-specific adaptation, to better guard the shoulder from injury. Thus, acromiohumeral distance measurement may help physical therapists/coaches decide which athletes could benefit from specific, additional exercises aimed at enlarging the subacromial space.

Quality assessment of shoulder plyometric exercises: Examining the relationship to scapular muscle activity.

OBJECTIVES: The purpose of the study was to evaluate performance quality of shoulder plyometric exercises, and examine the relationship to scapular muscle activation during an intense exercise bout. DESIGN: Observational study. SETTING: University laboratory. PARTICIPANTS: 32 healthy university students (male/female: 14/18) volunteers. MAIN OUTCOME MEASURES: Subjects performed 10 plyometric exercises. Surface EMG of upper (UT), middle (MT) and lower (LT) trapezius and serratus anterior (SA) was registered. A quality assessment questionnaire was administered at the beginning and end of the exercise bout. Muscle activation at the beginning and end was evaluated by t-test. Mixed repeated measures ANOVA was conducted to test the effects of criterion-quality, time, muscles, exercises, and their interactions. RESULTS: Increased EMG activation was noted in 34/40 cases, (21/40 significant (p < 0.05) changes). Quality assessment revealed a decline in the ability to maintain initial position (43% of subjects), failure to keep a consistent and symmetrical arc of motion (62% of subjects), and performance with trick movements (48% of subjects). Inability to keep a consistent arc of motion was significant in 4 exercises. CONCLUSIONS: The novel questionnaire may aid quality assessment during plyometric exercises. Ability to keep a consistent arc of motion was the most sensitive marker of decline of performance quality.

The isokinetic rotator cuff strength ratios in overhead athletes: Assessment and exercise effect.

OBJECTIVE: Muscle strength imbalance in the shoulder region can be considered as a predisposing factor in the development of movement dysfunctions, possibly leading to overuse injuries. Repetitive overhead throwing, performed in sports, may result in muscle imbalance between the external (ER) and internal (IR) rotators. Muscle strength measured with an isokinetic device, is reported as a concentric (CON) or eccentric (ECC) force. The balance between an agonist and an antagonist is mentioned as a ratio (CON/CON or ECC/CON). The aim of this systematic literature review is to provide an overview of the existing evidence considering the isokinetic muscle strength ratios of ER and IR of the shoulder in healthy overhead athletes. In addition, the effect of exercise programs on these ratios was investigated. METHODS: Two online databases (Web of Science and PubMed) were consulted using different search strategies. Articles were selected based on inclusion and exclusion criteria. All included articles were assessed on their methodological quality. RESULTS AND CONCLUSIONS: There is moderate evidence for a lower functional deceleration ratio (ECC ER/CON IR) at the dominant side. This lower ratio is due to a large overweight of CON IR strength on that side. There is no consensus about which exercise program is the most effective in altering the shoulder isokinetic strength ratios.

Upper Quadrant Field Tests and Isokinetic Upper Limb Strength in Overhead Athletes.

CONTEXT: Isokinetic testing is used to determine possible deficits in upper extremity strength in overhead athletes. Given that isokinetic testing is restricted to a laboratory setting, field tests, such as the Seated Medicine Ball Throw (SMBT) and Upper Quarter Y-Balance Test (YBT-UQ), were developed to assess upper body performance. The relationships between these field tests and isokinetic strength have not been examined. OBJECTIVE: To investigate the relationship between isokinetic strength testing for shoulder external and internal rotation and elbow flexion and extension and SMBT distance and YBT-UQ performance in overhead athletes. DESIGN: Cross-sectional study. SETTING: Institutional laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 29 healthy overhead athletes (14 men, 15 women; age = 21.6 ± 2.5 years, height = 177.7 ± 9.7 cm, mass = 70.3 ± 11.5 kg). INTERVENTION(S): A Biodex dynamometer was used to measure the isokinetic strength of the shoulder and elbow muscles. Upper extremity performance was assessed using the SMBT and YBT-UQ. MAIN OUTCOME MEASURE(S): We used Pearson correlation coefficients and coefficients of determination to analyze the relationship between SMBT and YBT-UQ performance and the isokinetic strength variables. RESULTS: We observed moderate to strong correlations between the SMBT and isokinetic shoulder and elbow strength (r range = 0.595-0.855) but no correlations between the YBT-UQ and isokinetic strength variables. The shared variance between these strength variables and the SMBT ranged from 35.4% to 64.5% for shoulder strength and 58.5% to 73.1% for elbow strength. CONCLUSIONS: These findings suggested that the SMBT is a reliable, low-cost, and easy- and quick-to-administer alternative to isokinetic testing for evaluating upper extremity strength in a clinical setting. Performance on the YBT-UQ did not seem to be related to upper limb strength and, therefore, cannot be used for this purpose. Using the YBT-UQ for other purposes may have value.

Scapular muscle activity in a variety of plyometric exercises.

BACKGROUND: Plyometric shoulder exercises are commonly used to progress from slow analytical strength training to more demanding high speed power training in the return to play phase after shoulder injury. The aim of this study was first, to investigate scapular muscle activity in plyometric exercises to support exercise selection in practice and second, to enhance understanding of how scapular muscles are recruited during the back and forth movement phase of these exercises. METHODS: Thirty-two healthy subjects performed 10 plyometric exercises while surface EMG-activity of the scapular muscles (upper (UT), middle (MT) and lower trapezius (LT) and serratus anterior (SA)) was registered. A high speed camera tracked start and end of the back and forth movement. RESULTS: Mean scapular EMG activity during the 10 exercises ranged from 14.50% to 76.26%MVC for UT, from 15.19% to 96.55%MVC for MT, from 13.18% to 94.35%MVC for LT and from 13.50% to 98.50%MVC for SA. Anova for repeated measures showed significant differences in scapular muscle activity between exercises (p<0.001) and between the back and forth movement (p<0.001) within exercises. CONCLUSION: Plyometric shoulder exercises require moderate (31-60%MVC) to high (>60%MVC) scapular muscle activity. Highest MT/LT activity was present in prone plyometric external rotation and flexion. Highest SA activity was found in plyometric external rotation and flexion with Xco and plyometric push up on Bosu. Specific exercises can be selected that recruit minimal levels of UT activity (<15%): side lying plyometric external rotation and horizontal abduction or plyometric push up on the Bosu. The results of this study support exercise selection for clinical practice.

Prevention of shoulder injuries in overhead athletes: a science-based approach.

The shoulder is at high risk for injury during overhead sports, in particular in throwing or hitting activities, such as baseball, tennis, handball, and volleyball. In order to create a scientific basis for the prevention of recurrent injuries in overhead athletes, four steps need to be undertaken: (1) risk factors for injury and re-injury need to be defined; (2) established risk factors may be used as return-to-play criteria, with cut-off values based on normative databases; (3) these variables need to be measured using reliable, valid assessment tools and procedures; and (4) preventative training programs need to be designed and implemented into the training program of the athlete in order to prevent re-injury. In general, three risk factors have been defined that may form the basis for recommendations for the prevention of recurrent injury and return to play after injury: glenohumeral internal-rotation deficit (GIRD); rotator cuff strength, in particular the strength of the external rotators; and scapular dyskinesis, in particular scapular position and strength.

Prevention of shoulder injuries in overhead athletes: a science-based approach

The shoulder is at high risk for injury during overhead sports, in particular in throwing or hitting activities, such as baseball, tennis, handball, and volleyball. In order to create a scientific basis for the prevention of recurrent injuries in overhead athletes, four steps need to be undertaken: (1) risk factors for injury and re-injury need to be defined; (2) established risk factors may be used as return-to-play criteria, with cut-off values based on normative databases; (3) these variables need to be measured using reliable, valid assessment tools and procedures; and (4) preventative training programs need to be designed and implemented into the training program of the athlete in order to prevent re-injury. In general, three risk factors have been defined that may form the basis for recommendations for the prevention of recurrent injury and return to play after injury: glenohumeral internal-rotation deficit (GIRD); rotator cuff strength, in particular the strength of the external rotators; and scapular dyskinesis, in particular scapular position and strength.