Therapeutic Photobiomodulation Before Strenuous Exercise Attenuates Shoulder Muscle Fatigue.

CONTEXT: Photobiomodulation therapy (PBMT) applied as a preconditioning treatment before exercise has been shown to attenuate fatigue and improve skeletal muscle contractile function during high-intensity resistance exercise. Practical implications for preconditioning muscle with PBMT prior to fatiguing exercise include a safe and non-invasive means to enhance performance and reduce the risk of musculoskeletal injury. OBJECTIVE: To examine the muscle fatigue attenuating effects of PBMT on performance of the shoulder external rotator muscle group when applied as a preconditioning treatment before high-intensity, high-volume resistance exercise. DESIGN: Sham-controlled, cross-over design. SETTING: Laboratory. PARTICIPANTS: Twenty healthy men (n=8) and women (n=12) between the age of 18 and 30. INTERVENTION: PBMT was administered using a near-infrared laser (λ=810/980nm, 1.8 W/cm2, treatment area = 80cm2-120 cm2) to the shoulder external rotator muscles at a radiant exposure of 10 J/cm2. Subjects performed 12 sets of isokinetic shoulder exercise. Each set consisted of 21 concentric contractions of internal and external rotation at 60°/s. The sets were subdivided into 3 blocks of exercise [Block 1: sets 1-4; Block 2: sets 5-8; Block 3: sets 9-12]. MAIN OUTCOME MEASURES: normalized peak torque [Nm/kg], average peak torque [Nm], total work [Nm], and average power [W]. RESULTS: During the last block of exercise (sets 9-12), all performance measures for the active PBMT condition were 6.2% to 10% greater than the sham PBMT values (p < 0.02 to 0.001). CONCLUSIONS: PBMT attenuated fatigue and improved muscular performance of the shoulder external rotators in the latter stages of strenuous resistance exercise.

The Effect of Scapular Muscle Strengthening on Functional Recovery in Patients With Lateral Elbow Tendinopathy: A Pilot Randomized Controlled Trial.

CONTEXT: There is a lack of consensus on the best management approach for lateral elbow tendinopathy (LET). Recently, scapular stabilizer strength impairments have been found in individuals with LET. OBJECTIVE: The purpose of this study was to compare the effectiveness of local therapy (LT) treatment to LT treatment plus a scapular muscle-strengthening (LT + SMS) program in patients diagnosed with LET. DESIGN: Prospective randomized clinical trial. SETTING: Multisite outpatient physical therapy. PATIENTS: Thirty-two individuals with LET who met the criteria were randomized to LT or LT + SMS. INTERVENTIONS: Both groups received education, a nonarticulating forearm orthosis, therapeutic exercise, manual therapy, and thermal modalities as needed. Additionally, the LT + SMS group received SMS exercises. MAIN OUTCOME MEASURE: The primary outcome measure was the patient-rated tennis elbow evaluation; secondary outcomes included global rating of change (GROC), grip strength, and periscapular muscle strength. Outcomes were reassessed at discharge, 6, and 12 months from discharge. Linear mixed-effect models were used to analyze the differences between groups over time for each outcome measure. RESULTS: The average duration of symptoms was 10.2 (16.1) months, and the average total number of visits was 8.0 (2.2) for both groups. There were no significant differences in gender, age, average visits, weight, or height between groups at baseline (P > .05). No statistical between-group differences were found for any of the outcome measures. There were significant within-group improvements in all outcome measures from baseline to all follow-up points (P < .05). CONCLUSION: The results of this pilot study suggest that both treatment approaches were equally effective in reducing pain, improving function, and increasing grip strength at discharge as well as the 6- and 12-month follow-ups. Our multimodal treatment programs were effective at reducing pain and improving function up to 1 year after treatment in a general population of individuals with LET.

ANALYSIS OF RANGE OF MOTION IN FEMALE RECREATIONAL TENNIS PLAYERS WITH AND WITHOUT LATERAL ELBOW TENDINOPATHY.

BACKGROUND: Intrinsic factors including altered joint motion in the upper extremity may lead to altered biomechanics in tennis players and could result in symptoms of lateral elbow tendinopathy. PURPOSE: To compare upper extremity passive motion and elbow carrying angle between three groups of women: recreational tennis players with LET, non-symptomatic recreational tennis players, and a control group of non-tennis players. STUDY DESIGN: Cross-sectional. METHODS: A convenience sample of 63 women was recruited and placed into one of the three groups: non-symptomatic tennis players (NSTP), symptomatic tennis players (STP), and a control group. Elbow carrying angle, passive range of motion of the shoulder, elbow, forearm, and wrist were measured during a single session. RESULTS: A significant difference was found between the groups for wrist flexion (p < 0.00), forearm pronation (p = 0.002), elbow flexion (p = 0.020) and extension (p = 0.460), as well as shoulder internal rotation (p < 0.00). No significant differences were found in other motions or carrying angle between the three groups (p =0.059). Post-hoc comparisons indicated that shoulder internal rotation and wrist flexion was less in both STP and NSTP groups compared with the control group. Elbow flexion and forearm pronation were greater in STP than the other two groups. CONCLUSION: Impairments including loss of shoulder internal rotation and wrist flexion and greater motion at the elbow and forearm were found in the UE of symptomatic tennis players. Evaluation of passive motion and muscle length should be performed prior to establishing a rehabilitation plan for symptomatic tennis players. LEVELS OF EVIDENCE: 3.

Do joint mobilizations assist in the recovery of lateral elbow tendinopathy? A systematic review and meta-analysis.

STUDY DESIGN: Systematic review. INTRODUCTION: No consensus exists as to which are the most effective methods to treat the symptoms associated with lateral elbow tendinopathy (LET). Research has suggested that joint mobilizations may assist in the recovery of patients with LET. PURPOSE OF THE STUDY: To determine if joint mobilizations are effective in improving pain, grip strength, and disability in adults with LET. METHODS: Searches in 3 databases were performed to identify relevant clinical trials. Reviewers independently extracted data and assessed the methodological quality. Summary measures of quantitative data were extracted or calculated where possible. Appropriate data were pooled for meta-analysis using a random-effects model. RESULTS: A total of 20 studies met the inclusion criteria; 7 were included in the meta-analysis. Studies were broadly classified into 3 groups: mobilization with movement (MWM), Mill's manipulation, and regional mobilization techniques. Pooled data across all time periods demonstrated a mean effect size of 0.43 (95% confidence interval [CI]: 0.15-0.71) for MWM on improving pain rating, and 0.31 (95% CI: 0.11-0.51) for MWM on improving grip strength, 0.47 (95% CI: 0.11-0.82) for Mill's manipulation on improving pain rating. A mean effect size of -0.01 (95% CI: -0.27 to -0.26) shows Mill's manipulation did not improve pain free grip strength. Functional outcomes varied considerably among studies. Pain, grip strength, and functional outcomes were improved with regional mobilizations. CONCLUSION: There is compelling evidence that joint mobilizations have a positive effect on both pain and/or functional grip scores across all time frames compared to control groups in the management of LET.

The effect of visual perturbation upon femoral acceleration during the single and bilateral squat.

OBJECTIVES: Record femoral accelerations using a smartphone accelerometer attached to the distal thigh during single-legged (SLS) and bilateral squats, and each squat condition occurred under two visual conditions: 1) normal vision and 2) visual perturbation with stroboscopic glasses. DESIGN: Repeated-measures cross-over with counter-balanced order for four total conditions. SETTING: Laboratory. PARTICIPANTS: 22 females and 16 males without lower extremity pathologies. MAIN OUTCOME MEASURES: 2D video assessment of frontal plane projection angle, composite amplitude index of smartphone accelerometer measurements, and bivariate correlations between these two outcomes. RESULTS: A significant interaction was found for stance x vision as the difference occurred within the SLS stance condition between the visual conditions (Normal: 9.85 ± 0.06; Stroboscopic: 9.86 ± 0.07; p = 0.008 with an adjusted alpha of 0.25). Femoral accelerations were not associated (r = -0.07) with 2D video assessment of frontal plane projection angle. CONCLUSIONS: Similar to other studies using smartphone accelerometry to assess movement quality, we found that the device could detect movement variation via femoral accelerations during SLS with visual perturbation in healthy individuals.

Spine biomechanics associated with the shortened, modern one-plane golf swing.

The purpose of this study was to compare kinetic, kinematic, and performance variables associated with full and shortened modern backswings in a skilled group of modern swing (one-plane) golfers. Shortening the modern golf backswing is proposed to reduce vertebral spine stress, but supporting evidence is lacking and performance implications are unknown. Thirteen male golfers performed ten swings of each swing type using their own 7-iron club. Biomechanical-dependent variables included the X-Factor kinematic data and spine kinetics. Performance-related dependent variables included club head velocity (CHV), shot distance, and accuracy (distance from the target line). Data were analysed with repeated measures ANOVA with an a priori alpha of 0.05 (SPSS 22.0, IBM, Armonk, NY, USA). We found significant reductions for the X-Factor (p < 0.05) between the full and shortened swings. The shortened swing condition ameliorated vertebral compression force from 7.6 ± 1.4 to 7.0 ± 1.7 N (normalised to body weight, p = 0.01) and significantly reduced CHV (p < 0.05) by ~2 m/s with concomitant shot distance diminution by ~10 m (p < 0.05). Further research is necessary to examine the applicability of a shortened swing for golfers with low back pain.

Integrating shoulder and core exercises when rehabilitating athletes performing overhead activities.

Athletes performing overhead activities are at risk of sustaining both overuse and traumatic shoulder injuries. Research studies utilizing electromyography have identified therapeutic exercises that are effective in the muscular activation of the rotator cuff and the scapular stabilizers. Sports medicine professionals routinely prescribe these traditional therapeutic exercises when rehabilitating athletes. Failing to identify and address contributing musculoskeletal dysfunctions may delay an athlete's successful return to sport. Integrating shoulder and core exercises can address potential musculoskeletal dysfunctions while serving as a transitional program between the initial therapeutic exercises and the terminal return to sport rehabilitation program.

Ambient-temperature beverages are consumed at a rate similar to chilled water in heat-exposed workers.

Palatability of beverages has been shown to influence drinking patterns and hydration. Cool beverages are known to enhance palatability; however, situations exist in which cooling is not possible. The purpose of this study was to determine the palatability of a variety of flavors of ambient temperature beverages. Ten healthy males performed two work trials in a temperature-controlled environment (WBGT = 30 degrees C; wet = 25 degrees C, dry = 40 degrees C, globe = 41 degrees C). In one trial, the subjects had only chilled water to drink. In the second trial the subjects drank their choice (any or all) of five ambient temperature beverages (water, fruit punch, lemon-lime, orange, and cola). Repeated measures ANOVA showed no difference in absolute or relative fluid consumption between the two trials (chilled = 1730 +/- 316 mL and 21 +/- 5 mL/kg; ambient [all five beverages combined] = 1510 +/- 219 mL and 19 +/- 4 mL/kg). There was no difference in the rate of fluid consumption between the two trials (608 +/- 88 mL/30 min and 674 +/- 82 mL/30 min, p > 0.05). Additionally, when combining all ambient-temperature, flavored beverages, consumption was significantly greater than that of ambient temperature water (1245 +/- 206 vs. 255 +/- 86 mL, p < 0.05). These findings demonstrate that providing ambient temperature beverages in a hot condition results in fluid consumption values similar to chilled water. These findings are relevant to industry in that there may be times when workers are at risk for heat-related illness due to dehydration and chilled beverages are not available. By providing flavored beverages, fluid consumption may be maintained and degree of heat-illness may be lessened.

The effects of repetitive overhead throwing on shoulder rotator isokinetic work-fatigue.

BACKGROUND: Muscle strength and endurance of the shoulder rotators is important for overhead throwing performance and dynamic glenohumeral stability. Baseball pitching is distinguished as an intermittent activity with explosive, high intensity muscle contractions separated by periods of rest. Rotator cuff muscle performance could acutely decrease due to fatigue associated with bouts of throwing. OBJECTIVE: This study examined the effects of repeated overhead throwing upon isokinetic muscle performance of the shoulder rotators. METHODS: Repeated-measures analyses of vari-ance were used to compare peak torque, total work, and work-fatigue by muscle group, time, and contraction type. Ten collegiate baseball pitchers underwent isokinetic testing of the internal (IR) and external shoulder (ER) rotators one week before and immediately after a throwing protocol of 60 maximal-effort pitches arranged into four innings of 15 pitches per inning. Isokinetic testing consisted of 12 concentric and eccentric repetitions at 300 deg/sec for internal and external rotation of the throwing extremity. RESULTS: The main effect of time and the interaction of muscle group and contraction type were significant for work-fatigue. Post-hoc analysis revealed that subjects had significantly greater eccentric IR work-fatigue (13.3 + 1%) compared to the pre-test (7.3 + 2%). DISCUSSION AND CONCLUSIONS: Throwing-related fatigue affected both muscle groups, especially the IR, which has implications for dynamic glenohumeral stability. Rehabilitation and conditioning programs for competitive baseball pitchers should emphasize eccentric muscle endurance training of the shoulder rotators.

Influence of Hydration and Electrolyte Supplementation on Incidence and Time to Onset of Exercise-Associated Muscle Cramps.

Context: Exercise-associated muscle cramps (EAMCs) are common among physically active individuals and are temporarily disabling; therefore, prevention is of great interest.Objective: To determine the role of hydration and electrolyte supplementation in the prevention of EAMCs.Design: Each subject completed 2 counterbalanced trials in a repeated-measures design.Setting: University of Alabama.Patients or Other Participants: College-aged men (n = 13) with a history of EAMCs.Intervention(s): In each trial, participants performed a calf-fatiguing protocol to induce EAMCs in the calf muscle group. Each trial was performed in a hot environment (dry bulb temperature of 37 degrees C, relative humidity of 60%). In the carbohydrate-electrolyte trial, subjects consumed, at a rate similar to sweat loss, a carbohydrate-electrolyte beverage with sodium chloride added. In the hypohydration trial, subjects were not allowed to consume any fluids.Main Outcome Measure(s): We measured the incidence and time to onset of EAMCs.Results: Nine participants experienced cramps in the carbohydrate-electrolyte trial, compared with 7 in the hypohydration trial. Of the 7 individuals who had EAMCs in both trials, exercise duration before onset was more than doubled in the carbohydrate-electrolyte trial (36.8 +/- 17.3 minutes) compared with the hypohydration trial (14.6 +/- 5.0 minutes, P < .01).Conclusions: Consumption of a carbohydrate-electrolyte beverage before and during exercise in a hot environment may delay the onset of EAMCs, thereby allowing participants to exercise longer. However, it appears that dehydration and electrolyte loss are not the sole causes of EAMCs, because 69% of the subjects experienced EAMCs when they were hydrated and supplemented with electrolytes.

A Compositional Analysis of a Common Acetic Acid Solution With Practical Implications for Ingestion.

OBJECTIVE: Acetic acid solutions, such as pickle juice (PJ), have gained anecdotal popularity among certified athletic trainers and other sports medicine professionals as remedies for exercise-associated muscle cramps. The aims of this study were 2-fold: (1) to report compositional analyses of 2 common types of PJ and (2) to discuss implications for ingestion following current National Athletic Trainers' Association (NATA) fluid-replacement guidelines. DESIGN AND SETTING: Biochemical laboratory analyses of 2 PJ sample types. MEASUREMENTS: Compositional analyses were performed in triplicate and compared with a 1-way analysis of variance. RESULTS: Mean values for PJ with 220 mg of sodium per serving were carbohydrate, 4 +/- 0.2%; osmolality, 713 +/- 6 mOsm.kg H(2)O(-1); pH, 3.8 +/- 0.2; calcium, 0.5 +/- 0.02 g/L; potassium, 1.4 +/- 0.02 g/L; magnesium, 0.1 +/- 0.01 g/L; and sodium, 7.4 +/- 0.1 g/L. Mean values for PJ with 390 mg of sodium per serving were carbohydrate, 3 +/- 0.1%; osmolality, 1446 +/- 9 mOsm.kg H(2)O(-1); pH, 3.5 +/- 0.1 g/L; calcium, 0.1 +/- 0.01 g/L; potassium, 1.2 +/- 0.02 g/L; magnesium, 0.1 +/- 0.01 g/L; and sodium, 17.1 +/- 0.1 g/L. Differences between the 220 and 390 PJ were significant (P <.05) for osmolality, calcium, and sodium. CONCLUSIONS: Both types of PJ exceeded sodium concentration levels set by the current NATA guidelines for fluid replacement. Hypothetical dilution references are presented to assist the athletic trainer with fluid volumes necessary to dilute PJ. Ingestion of PJ or other hypertonic fluids should be followed by ingestion of hypotonic or isotonic fluids to ensure that ingested amounts of sodium fall within the current NATA guidelines. Volumes for proper dilution may be substantial.