Exercise prescription for overhead athletes with shoulder pathology: a systematic review with best evidence synthesis

Variation of muscle recruitment during exercises performed below horizontal arm elevation that target the lower trapezius: A repeated measures cross-sectional study on asymptomatic individuals

The gold standard exercise for recruitment of the lower trapezius is the Y prone exercise which is performed above 90° of shoulder elevation. However, clinicians often prescribe exercises that avoid high elevation postures during early stages of rehabilitation. Comparatively little data exists on relative muscle recruitment during lower arm elevation exercises. This study examined the EMG activity of four shoulder girdle muscles during four exercises accomplished below 90° of shoulder elevation and compared them to the Y prone while considering sex effects. Variance across exercises of the ratio between upper trapezius and lower trapezius was also explored. 32 healthy participants completed standardized muscle-specific MVCs and two repetitions of each exercise. The side lying external rotation and the wall slide exercises produced the highest peak EMG for the lower trapezius, both 33 and 29% lower than the Y Prone. For the upper trapezius to lower trapezius ratio, the side lying external rotation elicited the lowest value, followed by the Y prone and wall slide (53 and 59% respectively higher). Sex influenced some EMG values, typically interacting with exercise type. Thus, side lying external rotation and the wall slide are recommended for targeting the lower trapezius muscle during early rehabilitation.

The Artificial Intelligence System for the Generation of Sports Education Guidance Model and Physical Fitness Evaluation Under Deep Learning

In recent years, China's achievements in artificial intelligence (AI) have attracted the attention of the world, and AI technology has penetrated into all walks of life. In particular, the in-depth integration of AI technology with sports education guidance and physical fitness evaluation has achieved very significant progress and results, which has improved the quality of life of people and provided more high-quality, customized, and personalized health management services for human beings. This study aimed to explore the application model of deep learning in sports education and guidance and in the analysis of the residents' physical fitness, so as to formulate a personalized and intelligent exercise program. The residents of A and B units are selected as the research object to evaluate the physical fitness. Subsequently, the self-designed questionnaire is used to survey the chronic disease online, and the acquired data are put into a deep learning model for the analysis to obtain the physique scoring results and exercise guidance. According to the results of physical fitness evaluation, the proportion of overweight was the highest (40.4%), followed by fatty liver (24.3%) and hyperlipidemia (20.4%), showing high incidence in people aged 41-50 years. The highest incidence of female gynecological diseases was gout (23.0%) and hyperlipidemia (20.6%). After exercise therapy, the scores were excellent and good. Conclusions: The database SQL Server 2005 was a platform for storing all kinds of data and knowledge-based rule information. The user's access service was provided by the remote server via the browser. Therefore, building a rule-based reasoning mechanism can realize physical test data collection, physical fitness evaluation, and information management for improving physical fitness.

Shoulder electromyography activity during push-up variations: a scoping review

BACKGROUND

Push-ups (PU) are a common closed chain exercise used to enhance shoulder girdle stability, with variations that alter the difficulty or target specific muscles. To appropriately select and prescribe PU exercises, an understanding of muscle activity during variations of the PU is needed. The purpose of this scoping review was to identify common PU variations and describe their muscle activation levels.

METHODS

Databases searched included PubMed, CINAHL, Scopus, and SPORTDiscus for articles published between January 2000 and November 2019.

RESULTS

Three hundred three articles were screened for eligibility with 30 articles included in the analysis. Six PU types and five muscles met the criteria for analysis. Weighted mean electromyography (EMG) amplitude was calculated for each muscle across PU types and for each PU type as a measure of global muscle activity. Triceps and pectoralis major had the highest EMG amplitude during unstable, suspension, incline with hands on a ball and the standard PU. Serratus anterior had the highest EMG amplitude during PU plus and incline PU. The greatest global EMG amplitude occurred during unstable surface PU.

DISCUSSION

These results provide clinicians with a framework for prescribing PU to target specific muscles and scale exercise difficulty to facilitate rehabilitation outcomes.

Co-creation of an exercise inventory to improve scapular stabilization and control among individuals with rotator cuff-related shoulder pain: a survey-based study amongst physiotherapists

Background

Scapular stabilization exercises (SSE) are often included in the treatment of individuals with rotator cuff-related shoulder pain (RCRSP) to decrease pain and improve function. These SSE typically aim to strengthen the scapular muscles and optimize dynamic neuromuscular control of the scapula, which may improve overall shoulder stability and movement quality. No consensus of the recommended SSE for the management of RCRSP is available. Hence, this study aimed to consult physiotherapists to co-create an inventory of recommended SSE based on the exercise’s relevance and frequency of prescriptions for the rehabilitation of individuals with RCRSP.

Methods

A group of 16 physiotherapists with experience in treating shoulder pain participated in a sequential consultation incorporating two distinct rounds of consultation focusing on SSE (modified Delphi design). In round 1, physiotherapists identified and demonstrated up to 10 SSE that they commonly recommend or use among individuals with RCRSP. The description and performance of all SSE were audio and video recorded. All SSE suggested by more than one participant in round 1 advanced to round 2. In round 2, physiotherapists rated these SSE on a 4-point Likert scale according to their perceived relevance and frequency of prescription for this population.

Results

In round 1, out of the 25 SSE recommended by participants, 19 SSE (76.0%) were recommended by more than one physiotherapist and advanced to round 2. In round 2, 13 SSE were consensually classified (agreement ≥75%) as being relevant for the rehabilitation of individuals with RCRSP. SSE targeting the recruitment of the serratus anterior and lower trapezius muscles were considered the most relevant for the management of RCRSP, whereas SSE targeting neuromuscular scapular control were the most prescribed SSE for the management of RCRSP.

Conclusions

An inventory composed of 13 SSE was co-created by physiotherapists based on their relevance and frequency of prescription for the rehabilitation of individuals with RCRSP. When designing an exercise program, physiotherapists can use this SSE inventory to inform their exercise selection, in combination with their current knowledge on shoulder rehabilitation, as well as patients’ preferences.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40945-022-00132-7.

Band Pull-Apart Exercise: Effects of Movement Direction and Hand Position on Shoulder Muscle Activity

Background/Purpose

The Elastic band pull-apart exercise is commonly used in rehabilitation. It involves pulling an elastic resistance band with both hands in horizontal abduction or diagonal arm movements. The extent of muscle activation during this exercise is unknown. The purpose of this study was to measure the electromyographic (EMG) activity of shoulder-girdle muscles during the pull-apart exercise using resistance bands and to determine the effects of arm position and movement direction on shoulder-girdle muscle activity.

Materials/Methods

Surface EMG activity was measured on the infraspinatus, upper trapezius, middle trapezius, lower trapezius and posterior deltoid of the dominant shoulder. After measurement of maximal voluntary contraction (MVC) for each muscle, subjects performed the band pull-apart exercise in three hand positions (palm up, neutral, palm down) and three movement directions (diagonal up, horizontal, diagonal down). Elastic band resistance was chosen to elicit moderate exertion (5/10 on the Borg CR10 scale). The order of the exercises was randomized and three repetitions of each exercise were performed. Mean peak EMG activity in each muscle across the repetitions was calculated and expressed as a percentage of MVC. Peak normalized EMG activity in each muscle was compared in two-way (hand position x direction) repeated-measures ANOVA.

Results

Data were collected from 10 healthy subjects (all males, age 36±12 years). Peak muscle activity ranged from 15.3% to 72.6% of MVC across muscles and exercise conditions. There was a significant main effect of hand position for the infraspinatus and lower trapezius, where muscle activity was highest with the palm up hand position (p < 0.001), and for the upper trapezius and posterior deltoid, where muscle activity was highest with the palm down position (p-value range < 0.001-0.004). There was a significant main effect of movement direction, where the diagonal up direction demonstrated the highest muscle activity for the infraspinatus, upper trapezius, lower trapezius, and posterior deltoid (p-value range < 0.001-0.02).

Conclusion

Altering hand position and movement direction during performance of an elastic band pull-apart exercise can affect magnitudes of shoulder-girdle muscle activity. Clinicians may alter a patient's hand position and movement direction while performing the band pull-apart exercise in order to increase muscle activity in target muscles or diminish muscle activity in other muscles.

Level of Evidence

2b.

Electromyography activation of shoulder and trunk muscles is greater during closed chain compared to open chain exercises

BACKGROUND

To compare the activation of shoulder and trunk muscles between six pairs of closed (CC) and open chain (OC) exercises for the upper extremity, matched for performance characteristics. The secondary aims were to compare shoulder and trunk muscle activation and shoulder activation ratios during each pair of CC and OC exercise.

METHODS

Twenty-two healthy young adults were recruited. During visit 1, the 5-repetition maximum resistance was established for each CC and OC exercise. During visit 2, electromyography activation from the infraspinatus (INF), deltoid (DEL), serratus anterior (SA), upper, middle and lower trapezius (UT, MT, LT), erector spinae (ES) and external oblique (EO) muscles was collected during 5-repetition max of each exercise. Average activation was calculated during the concentric and eccentric phases of each exercises. Activation ratios (DEL/INF, UT/LT, UT/MT, UT/SA) were also calculated. Linear mixed models compared the activation by muscle collapsed across CC and OC exercises. A paired t-test compared the activation of each muscle and the activation ratios (DEL/INF, UT/LT, UT/MT, UT/SA) between each pair of CC and OC exercises.

RESULTS

The INF, LT, ES, and EO had greater activation during both concentric (p = 0.03) and eccentric (p < 0.01) phases of CC versus OC exercises. Activation ratios were lower in CC exercises compared to OC exercises (DEL/INF, 3 pairs; UT/LT, 2 pairs; UT/MT, 1 pair; UT/SA, 3 pairs).

CONCLUSION

Upper extremity CC exercises generated greater activation of shoulder and trunk muscles compared to OC exercises. Some of the CC exercises produced lower activation ratios compared to OC exercises.

2022 Bern Consensus Statement on Shoulder Injury Prevention, Rehabilitation, and Return to Sport for Athletes at All Participation Levels

There is an absence of high-quality evidence to support rehabilitation and return-to-sport decisions following shoulder injuries in athletes. The Athlete Shoulder Consensus Group was convened to lead a consensus process that aimed to produce best-practice guidance for clinicians, athletes, and coaches for managing shoulder injuries in sport. We developed the consensus via a 2-round Delphi process (involving more than 40 content and methods experts) and an in-person meeting. This consensus statement provides guidance with respect to load and risk management, supporting athlete shoulder rehabilitation, and decision making during the return-to-sport process. This statement is designed to offer clinicians the flexibility to apply principle-based approaches to managing the return-to-sport process within a variety of sporting backgrounds. The principles and consensus of experts working across multiple sports may provide a template for developing additional sport-specific guidance in the future. J Orthop Sports Phys Ther 2022;52(1):11-28. doi:10.2519/jospt.2022.10952.

Non-Operative Shoulder Dysfunction in the United States Military

INTRODUCTION

Recent epidemiological evidence shows that shoulder and upper-arm complaints impose a substantial burden on the armed forces of the United States and create significant challenges for all components of the physical fitness domain of total force fitness. Clinicians, epidemiologists, and health-services researchers interested in shoulder and upper-arm injuries and their functional limitations rarely have objective, validated criteria for rigorously evaluating diagnostic practices, prescribed treatments, or the outcomes of alternative approaches. We sought to establish and quantify patient volume, types of care, and costs within the Military Health System (MHS) in assessing and managing active duty members with nonoperative shoulder and upper-arm dysfunction.

MATERIALS AND METHODS

We performed a retrospective cohort study using data from the MHS Data Repository and MHS MART (M2) from fiscal year 2014 to identify active duty individuals with a diagnosis of shoulder and upper-arm injury or impairment defined by one of the International Classification of Disease Ninth Edition diagnosis codes that were selected to reflect nonoperative conditions such as fractures or infections. Statistical analyses include descriptive statistics on patient demographics and clinical visits, such as the range and frequency of diagnoses, number and types of appointments, and clinical procedure information following the diagnosis. We also examined treatment costs related to shoulder dysfunction and calculated the total cost to include medications, radiological, procedural, and laboratory test costs for all shoulder dysfunction visits in 2014 and the average cost for each visit. We further examined the category of each medication prescribed.

RESULTS

A total of 55,643 individuals met study criteria and accrued 193,455 shoulder-dysfunction-related clinical visits in fiscal year 2014. This cohort represents approximately 4.8% of the 1,155,183 active duty service members assigned to the United States and its territories during FY 2014. Most patients were male (85.32%), younger (85.25% were under 40 years old), and Caucasian/White (71.12%). The most common diagnosis code was 719.41 (pain in joint, shoulder region; 42.48%). The majority of the patients 42,750 (76.8%) had four or fewer medical visits during the study period and 12,893 (23.2%) had more than four visits. A total of 4,733 patients (8.5%) underwent arthrocentesis aspiration or injection. The total cost for all visits was $65,066,767.89. The average and median cost for each visit were $336.34 (standard deviation was $1,493.87) and $163.11 (range was from 0 to $84,183.88), respectively. Three out of four patients (75.3%) underwent radiological examinations, and 74.2% of these individuals had more than one radiological examination. Medications were prescribed to 50,610 (91.0%) patients with the three most common being IBUPROFEN (12.21%), NAPROXEN (8.51%), and OXYCODONE-ACETAMINOPHEN (5.04%), respectively.

CONCLUSIONS

Nearly 1 in 20 active duty military service members presented for nonoperative care of shoulder and/or upper-arm dysfunction during FY2014. Further examinations of the etiology and potential impact of shoulder/upper-arm dysfunction on force readiness are clearly warranted, as are additional studies directed at identifying best practices for preventing injury-related dysfunction and determining best practices for the treatment of shoulder dysfunction to optimize service member fitness and force readiness.

Effectiveness of shoulder injury prevention programs in an overhead athletic population: A systematic review

OBJECTIVE

To analyze the effectiveness of shoulder injury prevention programs in overhead athletes.

DESIGN

Systematic Review.

METHODS

CINAHL, Embase, PubMed, and SPORTDiscus electronic databases were searched from database inception through December 2020 for randomized controlled or prospective cohort studies that implemented shoulder injury prevention programs in overhead athletes and reported shoulder injury incidence rates.

RESULTS

Seven studies fulfilled the inclusion criteria. Two studies reported on odds ratios (OR) that resulted in a reduction of shoulder injuries in overhead athletes following shoulder strengthening and flexibility exercises (OR, 0.72; 95% CI; 0.52, 0.98; OR, 0.22; 95% CI; 0.06, 0.75). One study reported on hazard ratio (HR) that resulted in a reduction of shoulder injuries following stretching of the posterior capsule (HR, 0.36; 95% CI; 0.13, 0.95).

CONCLUSION

There is limited research surrounding the effectiveness of shoulder injury prevention programs in overhead athletes specific to injury reduction. Only three studies reported a favorable effect in terms of injury prevention, with only one study at low risk of bias. At present, no conclusions can be made regarding the effectiveness of shoulder injury prevention programs in the overhead athlete.

Electromyographic Profile of the Shoulder During Stability Exercises With Kettlebells

CONTEXT

Shoulder rehabilitation can be a difficult task due to the dynamic nature of the joint complex. Various weight training implements, including kettlebells (KB), have been utilized for therapeutic exercise in the rehabilitation setting to improve shoulder girdle strength and motor control. The KBs are unique in that they provide an unstable load and have been purported to promote greater muscle activation versus standard dumbbells. Recent literature has examined the efficacy of KB exercises for global strengthening and aerobic capacity; however, electromyographic data for shoulder-specific activities are lacking.

OBJECTIVE

To examine muscle activation patterns about the rotator cuff and scapular musculature during 5 commonly-utilized KB exercises.

DESIGN

Cross-sectional analysis of a single group.

SETTING

Clinical biomechanics laboratory.

PARTICIPANTS

Ten participants performed all exercises in a randomized order.

MAIN OUTCOME MEASURES

Mean electromyographic values for each subject were compared between exercises for each target muscle.

RESULTS

Significant differences (P < .05) between exercises were observed for all target muscles except for the infraspinatus.

CONCLUSIONS

The data in this study indicates that certain KB exercises may elicit activation of the shoulder girdle at different capacities. Physical therapy practitioners, athletic trainers, and other clinical professionals who intend to optimize localized strengthening responses may elect to prescribe certain exercises over others due to the inherent difference in muscular utilization. Ultimately, this data may serve to guide or prioritize exercise selection to achieve higher levels of efficacy for shoulder strength and stability gains.

The effects of shoe type on lower limb venous status during gait or exercise: A systematic review

This systematic review evaluated the literature pertaining to the effect of shoes on lower limb venous status in asymptomatic populations during gait or exercise. The review was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed-NCBI, EBSCO Host, Cochrane Library and Science Direct databases were searched (March 2019) for words around two concepts: shoes and venous parameters. The inclusion criteria were as follows: (1) the manuscript had to be published in an English-language peer-reviewed journal and the study had to be observational or experimental and (2) the study had to suggest the analysis of many types of shoes or orthotics on venous parameters before, during and/or after exercise. Out of 366 articles, 60 duplications were identified, 306 articles were analyzed, and 13 articles met the eligibility criteria after screening and were included. This review including approximately 211 participants. The methodological rigor of these studies was evaluated with the modified Downs and Black quality index. Nine studies investigated the effect of shoes on blood flow parameters, two on venous pressure and two on lower limb circumferences with exercise. Evidence was found that unstable shoes or shoes with similar technology, sandals, athletic or soft shoes, and customized foot orthotics elicited more improvement in venous variables than high-heeled shoes, firm shoes, ankle joint immobilization and barefoot condition. These venous changes are probably related to the efficiency of muscle pumps in the lower limbs, which in turn seem to be dependent on shoe features associated with changes in the kinetics, kinematics and muscle activity variables in lower limbs during gait and exercise.

Analysis of Scapular Muscle EMG Activity During Elastic Resistance Oscillation Exercises From the Perspective of Different Arm Positions

BACKGROUND

Little is known about the optimal exercise intensity and the effects of arm position on elastic resistance exercise. The purpose of this study was to investigate scapular muscle activity in different arm positions utilized during standing elastic resistance exercise.

HYPOTHESIS

Lower trapezius (LT), serratus anterior (SA), and infraspinatus (IS) muscle activity will vary across arm positions above shoulder level. Also, oscillation resistance exercise will result in increased muscle activity compared with isometric contraction.

STUDY DESIGN

Controlled laboratory study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 19 uninjured male collegiate baseball players volunteered to participate in this study. The electromyography (EMG) activity of the LT, upper trapezius (UT), middle deltoid (MD), SA, and IS muscles was determined using surface EMG in 3 arm positions: diagonal pattern 1 (D1), 120° of shoulder abduction (120), and 90° shoulder abduction with external rotation and elbow flexion (90/90) during both isometric contraction and oscillation resistance exercise.

RESULTS

No difference in EMG activity of the LT muscle was found between the 120 and 90/90 position. However, the 120 position increased UT and MD muscle activity significantly more than those of the 90/90 position. The D1 arm position significantly increased SA muscle activity more than the 120 and 90/90 positions while the LT muscle activity was nearly silent.

CONCLUSION

The standing 90/90 position effectively generated both LT and IS muscle EMG activity while minimizing both UT and MD muscle activity.

CLINICAL RELEVANCE

The use of oscillation movements under elastic loading can create high muscle activation in the LT muscle without an adverse effect of the humeral head position and scapular rotation.

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.

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.

In situ repair of partial-thickness rotator cuff tears: a critical analysis review

After failed conservative management, operative intervention is typically indicated for patients with partial-thickness rotator cuff tears (PTRCTs) with persistent pain and disability symptoms.

For PTRCTs involving < 50% of the tendon thickness, debridement with or without acromioplasty resulted in favourable outcomes in most studies.

For PTRCTs involving > 50% of the tendon thickness, in situ repair has proven to significantly improve pain and functional outcomes for articular and bursal PTRCTs.

The few available comparative studies in the literature showed similar functional and structural outcomes between in situ repair and repair after conversion to full-thickness tear for PTRCTs.

Most non-overhead athletes return to sports at the same level as previous to the injury after in situ repair of PTRCTs. However, rates of return to preinjury level of competition for overhead athletes have been generally poor regardless of the utilized technique.

During long-term follow-up, arthroscopic in situ repair of articular and bursal PTRCTs produced excellent functional outcomes in most patients, with a low rate of revision.

Cite this article: EFORT Open Rev 2020;5:138-144. DOI: 10.1302/2058-5241.5.190010

Muscle Activity Ratios of Scapular Stabilizers During Closed Kinetic Chain Exercises in Healthy Shoulders: A Systematic Review

CONTEXT

Selective strengthening of scapular stabilizers is one of the emphases of the recent literature. Closed kinetic chain (CKC) exercises are used extensively in shoulder rehabilitation. However, a limited number of studies have reported scapular muscle ratios during CKC exercises.

OBJECTIVES

To determine the CKC exercises producing the optimal ratios of the scapular stabilizer muscles in healthy shoulders.

EVIDENCE ACQUISITION

A systematic search within PubMed, Embase, CINAHL Plus, and SPORTDiscus with Full Text and ULAKBIM National Medical Database was performed up to January 2018. Studies were selected according to the predetermined criteria. If the pooled mean ratios (upper trapezius [UT]/middle trapezius [MT], UT/lower trapezius [LT], and UT/serratus anterior [SA]), which were calculated from the percentage of maximum voluntary contractions of muscles, were <0.60, these exercises were considered as ideal for higher activation of the MT, LT, and SA than the UT.

EVIDENCE SYNTHESIS

The search identified 1284 studies, and 29 observational studies were included for review. Seventy-nine CKC exercises were determined. Four exercises for the MT, 9 for the LT, and 59 for the SA were identified from the articles as being optimal exercises to activate the specified muscle more than the UT.

CONCLUSIONS

This review identified optimal CKC exercises that provide good ratios between the MT, LT, and SA with the UT. Most exercises have optimal UT/SA ratios, but some exercises performed on unstable surfaces may lead to excessive activation of the UT relative to the SA. For the UT/MT, the isometric low row, inferior glide, and half supine pull-up with slings are the ideal exercises. Isometric one-hand knee push-up variations seem to be the best choice for the UT/LT. The results suggest that many CKC exercises may be utilized to enhance scapular muscle balance when rehabilitating shoulder pathology.

Rehabilitation and Prehabilitation for Upper Extremity in Throwing Sports: Emphasis on Lacrosse

Lacrosse imposes multiple simultaneous physical demands during play including throwing and catching a ball while holding a crosse, running, cutting, and jumping. Often, these skills are completed while experiencing contact from another player leading to both on-and-off platform movements. Other motions include defensive blocking and pushing past defenders. Repetitive motions over sustained durations in practice or competition impart mechanical stresses to the shoulder or elbow joints, supportive muscles, and connective tissue. Preparation for lacrosse participation involves bilateral optimization of strength and durability of stabilizer muscles. Passing and shooting skills are encouraged to be equally effective on both sides; therefore, symmetric strength and flexibility are vital for prehabilitation and rehabilitation efforts. This article will: 1) provide insights on the upper-extremity musculoskeletal demands of lacrosse and related sports with similar throwing motion and 2) describe prehabilitation and rehabilitation methods that improve athlete durability and reduce likelihood of upper-extremity injury.

Vibration as an adjunct to exercise: its impact on shoulder muscle activation

PURPOSE

There is an interest within elite sport in understanding the impact of a vibrating platform as an adjunct to exercise in the training and rehabilitation of throwing athletes. However, there has been no comprehensive evaluation of its impact on the rotator cuff muscles or its effect on the timing of shoulder muscle recruitment more globally.

METHODS

Twenty healthy participants were recruited with EMG recorded from 15 shoulder girdle muscles. Isometric shoulder flexion at 25% maximal voluntary contraction was performed in three testing scenarios [no vibration; whole body vibration (WBV); and arm vibration (AV)]. A press up and triceps dips with and without vibration were also performed. Muscular recruitment was assessed pre- and post-vibration exposure as participants initiated forward flexion.

RESULTS

Activation of the anterior deltoid (p = 0.002), serratus anterior (p = 0.004), and rotator cuff muscles (p = 0.004-0.022) occurred significantly earlier following exposure to vibration. Significantly greater activation was seen in the anterior, middle and posterior deltoid, upper, middle and lower trapezius, serratus anterior, teres major, latissimus dorsi, supraspinatus, and infraspinatus when the isometric contraction was performed with either WBV and/or AV (p =  < 0.001-0.040). Similarly, increased activation was also demonstrated during the press up and triceps dips when performed with vibration.

CONCLUSION

The use of vibration as an adjunct to exercise provokes a near global increase in shoulder muscle activation level. Furthermore, exposure to vibration alters muscular recruitment improving readiness for movement. This has potential implications within elite sport for both training and game preparation; however, further longitudinal work is required.

Tuck Jump Assessment as an Indicator for Upper Extremity Injury

The purpose of this study was to determine if tuck jumps can be used as a dynamic movement assessment to ascertain a previous history of upper extremity injury in an overhead throwing sport. Seventy-one youth baseball and softball athletes (28 baseball/43 softball; 12.41±2.22 yrs.; 161.98±13.65 cm; 59.17 ± 14.90 kg) were recruited to participate and were placed in either the previous injury (N=18) or no previous injury (N=53) groups. Kinematic data were collected from jumps 4 through 8 during a trial of 10 tuck jumps performed at 100 Hz using an electromagnetic tracking system (trakSTAR ^TM , Ascension Technologies, Inc., Burlington, VT, USA) synced with the MotionMonitor ^® (Innovative Sports Training, Chicago, IL, USA). A logistic regression showed no significance in trunk flexion or upper leg elevation in the ability to determine upper extremity injury ( χ ² (1, N =71)=3.55, p =0.315). In conclusion, examining only trunk flexion and upper leg elevation during the tuck jump assessment (TJA) is not enough for clinicians to recognize previous upper extremity injury. Even though the body behaves as a kinetic chain, simplifying the dynamic movement assessment while not specifying the type of upper extremity injury is not favorable for the clinician to identify previous injury.