Flexor-Pronator Mass Training Exercises Selectively Activate Forearm Musculature.

Purpose/Hypothesis: The flexor-pronator mass of the forearm contributes dynamic stability to the medial elbow. Training this muscle group is essential for overhead athletes, however, there is lack of evidence supporting use of training exercises. The purpose of this study was to measure the extent of EMG activity of the flexor pronator musculature during two distinct forearm strengthening exercises using resistance bands. It was hypothesized that two exercises would elicit at least moderate level of muscle activity, but the activation would be different in the pronator versus the flexor muscles. Materials/Methods: 10 healthy subjects (all males, age 36±12 years) were included. Surface EMG activity was measured on three muscles of the dominant-side forearm: flexor carpi ulnaris (FCP), flexor digitorum superficialis (FDS), and pronator teres (PT). After measurement of maximal voluntary contraction (MVC) for each muscle, subjects performed wrist ulnar deviation and forearm pronation exercises using elastic band resistance. Resistance was set to elicit moderate exertion (5/10 on the Borg CR10 scale). Order of exercise was randomized and three repetitions of each exercise were performed. Mean peak EMG activity in each muscle across repetitions during the eccentric phase of each exercise was calculated and expressed as a percentage of MVC. Moderate level of activity was defined as 21% of MVC or higher. Peak normalized EMG activity in each muscle was compared using two-way (exercise x muscle) repeated-measures ANOVA with post-hoc pairwise comparisons if a significant interaction was found. Results: There was an exercise by muscle interaction effect (p<0.001). The ulnar deviation exercise selectively activated FCU (40.3%) versus FDS (19.5%, p=0.009) and PT (21.5%, p=0.022). Conversely, the pronation exercise selectively activated FDS (63.8%, p=0.002) and PT (73.0%, p=0.001) versus FDS (27.4%). Conclusion: The ulnar deviation and pronation exercises using elastic band resistance studied targeted and activated the flexor-pronator mass musculature. The ulnar deviation and pronation exercises using elastic band resistance are practical and effective means of training the flexor-pronator mass. These exercises can be readily prescribed to athletes and patients as part of their arm care program.

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.

MAPPING TENDERNESS TO PALPATION PREDICTS RETURN TO PLAY FOLLOWING ACUTE HAMSTRING STRAIN.

INTRODUCTION/PURPOSE: Currently there is little evidence supporting the use of objective tests, measures, or imaging to help predict time to return to sport (RTS) following a hamstring strain. The purpose of this study is to investigate the predictive value of tenderness to palpation (TTP) as measured by area and location following hamstring strain. STUDY DESIGN: Case Series. METHODS: Nineteen male athletes (age 28 ± 9 yr) who sustained an acute hamstring strain underwent hamstring tenderness mapping on initial evaluation. The length and width of tenderness of the hamstring was identified with manual palpation, outlined in pen, and was then calculated as a percentage of the length and width of the posterior thigh. All patients underwent the same hamstring rehabilitation protocol with remapping performed at specific stages in rehabilitation. The association between mapping tenderness indices and RTS was assessed by linear regression. RESULTS: The average length of the area of tenderness was 22 ± 12% with an average RTS of 43 ± 36 days. The length of the area of tenderness measured on initial evaluation was a strong predictor of RTS (R2 = 0.58, p<0.001; y = 2.3x - 6.2). Area of injury (R2 = 0.36, p = 0.006) and age (R2 = 0.27, p = 0.024) were also related to RTS, while width of injury (R2 = 0.006, p = 0.75) and location of injury were not (proximal-distal p = 0.62, medial-lateral p = 0.64). Adding age with length of injury into a multiple regression analysis improved the prediction of RTS (R2 = 0.73). The relationship between RTS and length of tenderness was relatively unchanged when the additional mapping indices taken during the course of rehabilitation were added to the analysis (R2 = 0.61, p<0.001; y = 2.3x - 4.4). This indicates that the regression equation can be used to estimate RTS regardless of when in the post injury/rehabilitation process the mapping is performed. CONCLUSIONS: The length of the area of tenderness to palpation of the injured hamstring muscle was highly predictive of RTS time. Based on the regression equation a patient with a length of tenderness of 10% would have an estimated RTS time of 17 days, while a tenderness length of 30% would be estimated to return in 63 days. This hamstring mapping technique described was predictive of the RTS and may be a useful clinical tool. LEVEL OF EVIDENCE: IIb.

Rehabilitation After Hamstring-Strain Injury Emphasizing Eccentric Strengthening at Long Muscle Lengths: Results of Long-Term Follow-Up.

CONTEXT: Hamstring-strain injuries have a high recurrence rate. OBJECTIVE: To determine if a protocol emphasizing eccentric strength training with the hamstrings in a lengthened position resulted in a low recurrence rate. DESIGN: Longitudinal cohort study. SETTING: Sports-medicine physical therapy clinic. PARTICIPANTS: Fifty athletes with hamstring-strain injury (age 36 ± 16 y; 30 men, 20 women; 3 G1, 43 G2, 4 G3; 25 recurrent injuries) followed a 3-phase rehabilitation protocol emphasizing eccentric strengthening with the hamstrings in a lengthened position. MAIN OUTCOME MEASURES: Injury recurrence; isometric hamstring strength at 80°, 60°, 40°, and 20° knee flexion in sitting with the thigh flexed to 40° above the horizontal and the seat back at 90° to the horizontal (strength tested before return to sport). RESULTS: Four of the 50 athletes sustained reinjuries between 3 and 12 mo after return to sport (8% recurrence rate). The other 42 athletes had not sustained a reinjury at an average of 24 ± 12 mo after return to sport. Eight noncompliant athletes did not complete the rehabilitation and returned to sport before initiating eccentric strengthening in the lengthened state. All 4 reinjuries occurred in these noncompliant athletes. At time of return to sport, compliant athletes had full restoration of strength while noncompliant athletes had significant hamstring weakness, which was progressively worse at longer muscle lengths (compliance × side × angle P = .006; involved vs noninvolved at 20°, compliant 7% stronger, noncompliant 43% weaker). CONCLUSION: Compliance with rehabilitation emphasizing eccentric strengthening with the hamstrings in a lengthened position resulted in no reinjuries.

Clinical outcomes of the addition of eccentrics for rehabilitation of previously failed treatments of golfers elbow.

INTRODUCTION AND PURPOSE: Eccentric training of the wrist extensors has been shown to be effective in treating chronic lateral epicondylosis. However, its efficacy in the treatment of medial epicondylosis has yet to be demonstrated. The objective of this study was to assess the effectiveness of a novel eccentric wrist flexor exercise added to standard treatment for chronic medial epicondylosis in patients who did not respond to previous therapeutic interventions for this disorder. NUMBER OF SUBJECTS: 20. MATERIALS/METHODS: Patients (13 men, 7 women; age 49±12 yr) with chronic medial epicondylosis who had failed previous treatment for this disorder (physical therapy 7, cortisone injection 7, PRP 1, NSAIDS 15) were prescribed isolated eccentrics in addition to wrist stretching, ultrasound, cross-friction massage, heat and ice. The specific isolated eccentric wrist flexor strengthening exercise performed by the patients involved twisting a rubber bar (Flexbar, Hygenic Corportation, Akron OH) with concentric wrist flexion of the noninvolved arm and releasing the twist by eccentrically contracting the wrist flexors of the involved arm (3 × 15 twice daily). A DASH questionnaire was recorded at baseline and again after the treatment period. Treating clinicians were blinded to baseline DASH scores. Treatment effect was assessed using paired t-test. Based on previous work it was estimated that with a sample of 20 patients there would be 80% power to detect a 13 point improvement in DASH scores (p<.05). RESULTS: The pathology was in the dominant arm of 18 patients and recurrent in 10. Primary symptomatic activities were golf (14), tennis (2), basketball (1), weight lifting (1), and general activities of daily living (2). There was a significant improvement in outcomes following the addition of isolated eccentrics (Pre DASH 34.7±16.2 vs. Post DASH 7.9±11.1, p<.001). For the 18 patients involved in sports, the sports module of the DASH score improved from 73.9±28.9 to 13.2±25.0, p<.001). Physical therapy visits ranged from 1-22 with an average of 12±6 and, average treatment duration of 6.1±2.5 wks (range 1-10). Home exercise program compliance was recorded for each subject (15 full, 3 mostly, 1 occasionally, 1 none). CONCLUSIONS: The outcome measure for chronic medial epicondylosis was markedly improved with the addition of an eccentric wrist flexor exercise to standard physical therapy. Given the inconsistent outcomes for patients previously treated with chronic medial epicondylosis the addition of isolated eccentrics seems warranted based on the results of this study. CLINICAL RELEVANCE: This novel exercise, using an inexpensive rubber bar, provides a practical means of adding isolated eccentric training to the treatment of chronic medial epicondylosis. LEVEL OF EVIDENCE: 2b.

Hamstring injury rehabilitation and prevention of reinjury using lengthened state eccentric training: a new concept.

BACK GROUND AND PURPOSE: Hamstring injury is a common occurrence in sport and there has been limited success in reducing this rate of recurrence to date. DESCRIPTION OF TOPIC WITH RELATED EVIDENCE: High speed running requires eccentric strength when the hamstring muscles are in a lengthened state. The lengthened state occurs when the hip is in flexion and the lower leg moves into extension, thus lengthening the two joint hamstring muscle over both articulations upon which they act. There is evidence to suggest that athletes who have sustained a hamstring strain lack strength when the muscle is utilized during performance in a lengthened state. PURPOSE: To examine the risk factors contributing to such a high recurrence rate and propose a unique rehabilitation strategy addressing these factors in order to decrease the rate of reinjury. DISCUSSION/RELATION TO CLINICAL PRACTICE: Failing to increase an athlete's eccentric strength in a lengthened position after a hamstring injury may predispose an athlete to subsequent reinjury. Incorporating lengthened state eccentric training may help reduce the rate of reinjury. LEVEL OF EVIDENCE: Level 5.