Does High Medial Elbow Stress During Pitching Compromise the Dynamic Stabilizers of The Elbow?

Background: The flexor carpi ulnaris (FCU) and flexor digitorum superficialis (FDS) are thought to provide dynamic stability to the medial elbow, with a lesser contribution from the pronator teres (PT). Hypothesis/Purpose: The purpose of this study was to determine if baseball pitchers with higher valgus elbow torque experience greater FCU and FDS strength loss. Study Design: Controlled Laboratory Study. Methods: A pilot study was performed to determine if middle and ring finger flexion strength tests preferentially activated the FCU and FDS versus the PT (10 men age 36±12 yr). EMG amplitudes, expressed as percent of maximal voluntary contraction (MVC) were compared between tests and muscles. In a field study of college baseball pitchers, middle finger, ring finger and grip strength were tested prior to, immediately after, and one day after 14 pitching performances in 10 pitchers (21±2 yr). Elbow valgus torque was measured from an inertial measurement unit, housed in a compression sleeve and pitchers were categorized as having high or low valgus torque. Results: For the pilot study EMG activations were 74% FDS, 66% FCU and 35% PT for the middle finger test (muscle effect p=0.032) and 93% FCU, 61% FDS and 23% PT for the ring finger test (muscle effect p=0.005). In the field study, pitchers with high valgus torque showed marked post-game middle finger fatigue (88% of baseline) and incomplete recovery the following day (95%), while pitchers with low valgus torque showed no strength loss (107% post game, 106% a day later; group x time p=0.022). Results were similar for ring finger strength (high torque: 94% post game 96% a day later; low torque: 114% post game 107% a day later; group x time p=0.048). By contrast, grip strength was not different between pitchers with high versus low valgus torque (p=0.143). Conclusion: High medial elbow stress during pitching fatigues the dynamic stabilizers of the medial elbow. Level of Evidence: Level 3©The Author(s).

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.

Role of Pelvis and Trunk Biomechanics in Generating Ball Velocity in Baseball Pitching.

ABSTRACT: Orishimo, KF, Kremenic, IJ, Mullaney, MJ, Fukunaga, T, Serio, N, and McHugh, MP. Role of pelvis and trunk biomechanics in generating ball velocity in baseball pitching. J Strength Cond Res 37(3): 623-628, 2023-The purpose of this study was to determine the impact of pelvis rotation velocity, trunk rotation velocity, and hip-shoulder separation on ball velocity during baseball pitching. Fastball pitching kinematics were recorded in 29 male pitchers (age 17 ± 2 years, 23 high school, 6 college). Pelvis and trunk angular velocities and hip-shoulder separation were calculated and averaged for the 3 fastest pitches. Associations between peak pelvis velocity, peak trunk velocity, hip-shoulder separation at foot contact, and ball velocity were assessed using Pearson correlation coefficients and multiple regression. The average ball velocity was 33.5 ± 2.8 m·s -1 . The average hip-shoulder separation at foot contact was 50 ± 12°. The peak pelvis velocity (596 ± 88°·s -1 ) occurred at 12 ± 11% of the time from stride foot contact to ball release, with the peak trunk velocity (959 ± 120°·s -1 ) occurring at 36 ± 11%. Peak trunk velocity was predictive of ball velocity ( p = 0.002), with 25% of the variability in ball velocity explained. No combination of factors further explained ball velocity. Hip-shoulder separation at foot contact (17%, p = 0.027), peak pelvis velocity (23%, p = 0.008), and the timing of peak pelvis velocity (16%, p = 0.031) individually predicted peak trunk velocity. The combination of peak pelvis velocity, hip-shoulder separation at foot contact, and the timing of peak trunk velocity explained 55% of the variability in trunk rotation velocity ( p < 0.001). These data highlight the importance of interactions between pelvis and trunk for maximizing velocity in pitching. Training to improve pelvis-trunk axial dissociation may increase maximal trunk rotation velocity and thereby increase ball velocity without increasing training load on the shoulder and elbow.

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.

Accelerated Muscle Recovery in Baseball Pitchers Using Phase Change Material Cooling.

PURPOSE: The purpose of this study was to document recovery after a pitching performance and determine whether prolonged postgame phase change material (PCM) cooling of the shoulder and forearm accelerates recovery. METHODS: Strength, soreness, and serum creatine kinase (CK) activity were assessed before and on the 2 d after pitching performances in 16 college pitchers. Pitchers were randomized to receive either postgame PCM cooling packs on the shoulder and forearm or no cooling (control). PCM packs were applied inside compression shirts and delivered cooling at a constant temperature of 15°C for 3 h. Strength was assessed for shoulder internal rotation (IR), external rotation (ER), empty can (EC) test, and grip. RESULTS: Total pitch count was 60 ± 16 for 23 PCM cooling games and 62 ± 17 for 24 control games (P = 0.679). On the days after pitching, IR strength (P = 0.006) and grip strength (P = 0.036) were higher in the PCM cooling group versus control. One day after pitching, IR strength was 95% ± 14% of baseline with PCM cooling versus 83% ± 13% for control (P = 0.008, effect size d = 0.91) and 107% ± 9% versus 95% ± 10% for grip strength (P = 0.022, effect size d = 1.29). There was a trend for greater ER strength with PCM cooling (P = 0.091, effect size d = 0.51). The EC strength was not impaired after pitching (P = 0.147) and was therefore unaffected by PCM cooling (P = 0.168). Elevations in soreness and CK were not different between treatments (treatment-time CK P = 0.139, shoulder soreness P = 0.885, forearm soreness P = 0.206). CONCLUSION: This is one of the first studies to document impairments in muscle function on the days after baseball pitching, and the first study showing a novel cryotherapy intervention that accelerates recovery of muscle function in baseball pitchers after a game.

ASSESSMENT OF HUMERAL TORSION BY PALPATION IN BASEBALL PITCHERS: A VALIDATION STUDY.

BACKGROUND/PURPOSE: Greater humeral retroversion has been associated with shoulder and elbow injuries. Methods for measuring torsion include radiography, computed tomography (CT) and sonography (US) which may be costly or unavailable. A palpation method might be a reliable alternative to imaging techniques. The purpose of the current study was to examine the construct validity of the palpation technique for humeral torsion by (1) determining if a side-to-side difference in humeral torsion (HT) could be detected in a cohort of baseball pitchers using the palpation technique and (2) compare the side-to-side difference in HT obtained through the palpation method to the US method. HYPOTHESIS: Clinical assessment of HT by palpation is reliable and is as accurate as sonographic HT measurements among overhead athletes. METHODS: Twenty collegiate and high school pitchers were assessed. Bilateral shoulder passive external rotation (ER) and internal rotation (IR) range of motion were measured. Humeral torsion was indirectly measured using sonographic and palpatory methods. Paired t-tests were used to determine HT side-to-side difference measured by US versus palpation. Pearson's correlation coefficient (r) was used to determine the relationship between HT side-to-side difference detected by palpation and US, and relationships among IR and ER of the shoulder and HT side to-side difference measurements. RESULTS: There was significantly greater HT in dominant versus nondominant arm assessed by both palpation (5°±5, p=0.0004) and ultrasound (9°±11, p=0.0007). There was a positive correlation between both methods of HT measurement (r = 0.522, p=0.018). Palpation significantly underestimated HT as compared to US measurements (difference 4°±9, p=0.048). Difference in IR between shoulders correlated with HT measured by palpation (r=-0.651, p=0.002) and US (r=0.569, p=0.009). Increased ER in the dominant versus nondominant arm correlated with the side-to-side difference in HT measured by both palpation (r = 0.509, p=0.02) and US (r = 0.602, p=0.005). CONCLUSION: Greater HT on the dominant versus nondominant shoulder via palpation indicated this method can be used to assess HT in pitchers. HT assessed by palpation correlated with HT assessed by US. However, the magnitude of side-to-side difference in HT was smaller with palpation compared to US, and the two techniques should not be used interchangeably. Nevertheless, assessment of HT via palpation is a reliable and practical method and its use should be encouraged. LEVEL OF EVIDENCE: Level 3, measurement study.

EMG OF SHOULDER MUSCLES DURING REACTIVE ISOMETRIC ELASTIC RESISTANCE EXERCISES.

BACKGROUND: Traditionally, shoulder isometrics are introduced in the early stages of shoulder rehabilitation. A patient's isometric torque output is based on a subjective perception of force generation. By utilizing elastic resistance elongation (strain) to standardize force output, clinicians could prescribe shoulder therapeutic isometrics based on % maximum voluntary contraction (%MVC). PURPOSE/HYPOTHESIS: The purpose of this study was to measure electromyographic (EMG) activity and determine the %MVC during shoulder flexion, external rotation and abduction isometrics at varying lengths of TheraBand® elastic resistance. It was hypothesized that increased elongation of progressive resistance bands would proportionately increase the %MVC of the shoulder musculature. STUDY DESIGN: Laboratory design using healthy subjects. METHODS: Eight healthy subjects (16 shoulders) (5 females, 3 males; avg. age 29.2) were tested. Surface EMG electrodes were placed over the anterior deltoid, middle deltoid, and infraspinatus muscles. A force transducer was anchored to a stable surface with its corresponding end in series with an extremity strap securely holding the elastic band. Subjects were asked to maintain shoulder position for the proper isometric contraction (flexion, abduction and external rotation) while taking incremental steps away from the anchored elastic resistance, to the beat of a metronome to clearly marked distances on the floor (50, 100, 150, 200 and 250% of band elongation). This was repeated with yellow, red, green, and blue TheraBand® resistance levels. Maximum voluntary contractions for both force and EMG were collected for each subject in all three test positions. EMG data were normalized and expressed as a %MVC. RESULTS: For external rotation and flexion, the infraspinatus and anterior deltoid activity increased with band elongation (p<0.01) and progressive colors (p<0.01). The increases in EMG activity with elongation plateaued with the yellow and red bands but continued to increase with the green and blue bands (p<0.01). The increase in infraspinatus and anterior deltoid EMG activity with progressive band color was more apparent for green and blue bands compared with yellow and red band (p<0.01). For the abduction exercise, middle deltoid activity increased with band elongation (p<0.01) and progressive color (p<0.01). In all three exercises, there was an increase in force exerted by the band with increasing length and band color (p < 0.001). However, while there were clear increases in force from red to green to blue, there was no difference in force between yellow and red regardless of elongation (p<0.01). CONCLUSION: Isometric flexion, external rotation and abduction muscle activity can be accurately prescribed clinically by adjusting the elongation and resistance associated with progressive colors of resistance bands. LEVEL OF EVIDENCE: 3.

CURRENT CONCEPTS AND TREATMENT OF PATELLOFEMORAL COMPRESSIVE ISSUES.

Patellofemoral disorders, commonly encountered in sports and orthopedic rehabilitation settings, may result from dysfunction in patellofemoral joint compression. Osseous and soft tissue factors, as well as the mechanical interaction of the two, contribute to increased patellofemoral compression and pain. Treatment of patellofemoral compressive issues is based on identification of contributory impairments. Use of reliable tests and measures is essential in detecting impairments in hip flexor, quadriceps, iliotibial band, hamstrings, and gastrocnemius flexibility, as well as in joint mobility, myofascial restrictions, and proximal muscle weakness. Once relevant impairments are identified, a combination of manual techniques, instrument-assisted methods, and therapeutic exercises are used to address the impairments and promote functional improvements. The purpose of this clinical commentary is to describe the clinical presentation, contributory considerations, and interventions to address patellofemoral joint compressive issues.

Functional Outcomes After Double-Row Versus Single-Row Rotator Cuff Repair: A Prospective Randomized Trial.

BACKGROUND: The functional benefits of double-row (DR) versus single-row (SR) rotator cuff repair are not clearly established. PURPOSE: To examine the effect of DR versus SR rotator cuff repair on functional outcomes and strength recovery in patients with full-thickness tears. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: Forty-nine patients were randomized to DR or SR repairs; 36 patients (13 women, 23 men; mean age, 62 ± 7 years; 20 SR, 16 DR) were assessed at a mean 2.2 ± 1.6 years after surgery (range, 1-7 years; tear size: 17 medium, 13 large, 9 massive). The following data were recorded prior to surgery and at follow-up: Penn shoulder score, American Shoulder and Elbow Surgeons (ASES), and Simple Shoulder Test (SST) results; range of motion (ROM) for shoulder flexion, external rotation (ER) at 0° and 90° of abduction, and internal rotation (IR) at 90° of abduction; and shoulder strength (Lafayette manual muscle tester) in empty- and full-can tests, abduction, and ER at 0° of abduction. Treatment (SR vs DR) × time (pre- vs postoperative) mixed-model analysis of variance was used to assess the effect of rotator cuff repair. RESULTS: Rotator cuff repair markedly improved Penn, ASES, and SST scores (P < .001), with similar improvement between SR and DR repairs (treatment × time, P = .38-.10) and excellent scores at follow-up (DR vs SR: Penn, 91 ± 11 vs 92 ± 11 [P = .73]; ASES, 87 ± 12 vs 92 ± 12 [P = .21]; SST, 11.4 ± 1.0 vs 11.3 ± 1.0 [P = .76]). Patients with DR repairs lost ER ROM at 0° of abduction (preoperative to final follow-up, 7° ± 10° loss [P = .013]). ER ROM did not significantly change with SR repair (5° ± 14° gain, P = .16; treatment by time, P = .008). This effect was not apparent for ER ROM at 90° of abduction (treatment × time, P = .26). IR ROM improved from preoperative to final follow-up (P < .01; SR, 17° ± 27°; DR, 7° ± 21°; treatment × time, P = .23). Rotator cuff repair markedly improved strength in empty-can (54%), full-can (66%), abduction (47%), and ER (54%) strength (all P < .001), with no difference between SR and DR repairs (P = .23-.75). All clinical tests with the exception of the lift-off test were normalized at follow-up (P < .05). CONCLUSION: Outcomes were not different between SR or DR repair, with generally excellent outcomes for both groups. Rotator cuff repair and subsequent rehabilitation markedly improved shoulder strength.

The Effect of a High Pitch Volume on Musculoskeletal Adaptations in High School Baseball Pitchers.

BACKGROUND: Shoulder range of motion and strength adaptations occur at an early age in baseball pitchers. PURPOSE/HYPOTHESIS: The purpose of this study was to examine the effect of pitch volume on in-season and year-to-year range of motion (ROM) and strength adaptations in high school baseball pitchers. The hypothesis was that a high pitch volume will not affect range of motion asymmetries but will impair supraspinatus strength. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Pre- and postseason ROM and strength measures were performed on pitchers from 3 high schools for 4 consecutive seasons, for a total of 95 player-seasons (mean ± SD participant age, 16 ± 1 years). Preseason measures were repeated the next year on players returning to the teams, for a total of 71 consecutive player-seasons. ROM tests included internal-external rotation and posterior shoulder flexibility. Strength tests (hand-held dynamometer) included internal-external rotation, supraspinatus, and scapular retraction. Pitchers were categorized by pitch count for the season (high, >400; moderate, 180-400; low, <180). ROM and strength changes in the dominant versus nondominant arm were assessed by analysis of variance. RESULTS: Dominant versus nondominant ROM differences did not change from pre- to postseason (P = .36-.99) or from one year to the next (P = .46-.86), with no effect of pitch volume (P = .23-.87). Supraspinatus strength decreased in the dominant arm during the season, with 13% loss in high-volume pitchers (P < .001) and insignificant losses in moderate- (6%) and low-volume pitchers (2%). Strength in other tests was unaffected by pitch volume. Consistent with physical development, strength increased bilaterally from one year to the next (supraspinatus, 12%; external rotation, 15%; internal rotation, 14%; scapular retraction, 23%; P < .001). Supraspinatus strength gain in the dominant arm was affected by prior pitch volume (P = .02): 24% in low-volume pitchers (P < .01), with no significant change in moderate-volume (0%; P = .99) or high-volume (5%; P = .99) pitchers. CONCLUSION: Dominant versus nondominant ROM differences did not progress during the season, or from one year to the next, and were unaffected by pitch volume. A high pitch volume was associated with in-season supraspinatus weakness and diminished strength gains from one year to the next. In conclusion, a high pitch volume appeared to have a catabolic effect on supraspinatus strength.

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.

Risk Factors for Shoulder and Elbow Injuries in High School Baseball Pitchers: The Role of Preseason Strength and Range of Motion.

BACKGROUND: Shoulder strength and motion deficits in high school baseball pitchers have been implicated in injury risk. PURPOSE/HYPOTHESIS: To prospectively determine if preseason strength and range of motion (ROM) are predictive of injury in high school baseball pitchers. It was hypothesized that ROM asymmetries and weakness would be predictive of injury. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Preseason strength and ROM measurements were made on 101 pitchers from 4 different high schools over 4 seasons (total 166 pitcher-seasons: 25 freshman, 46 junior varsity, and 95 varsity player-seasons). Glenohumeral internal rotation (IR), glenohumeral external rotation, and posterior shoulder ROM were measured bilaterally. Strength in IR, external rotation, supraspinatus (empty-can test), and scapular retraction was measured bilaterally (handheld dynamometer). Injury incidence (injuries per 1000 pitches) was computed for players categorized as above normal (≥1 SD above the mean), normal (within 1 standard deviation of the mean), and below normal (≤1 SD below the mean) for each potential risk factor. Injury was defined as a missed game or practice because of shoulder or elbow problem. RESULTS: There were 28 upper extremity injuries (19 shoulder, 9 elbow; incidence, 0.58 injuries/1000 pitches). There was a trend for supraspinatus weakness to be associated with increased injury risk (relative risk [RR], 3.60; 95% CI, 0.75-17.32; P = .09). When analyzing major injuries only (>3 missed games), preseason supraspinatus weakness was significantly associated with increased injury risk (RR, 4.58; 95% CI, 1.40-15.01; P = .02). Paradoxically, pitchers with no IR loss were at increased risk compared with pitchers with ≥20° loss (RR, 4.85; 95% CI, 1.01-23.29; P = .04). Other ROM and strength measures were unrelated to injury risk. CONCLUSION: Although excessive loss of IR ROM is thought to be a risk factor for injury, the opposite was the case in this study. The absence of IR ROM loss in high school pitchers may indicate inadequate prior exposure to pitching, resulting in increased injury risk. Preseason supraspinatus weakness was associated with increased risk for a major injury, and preventative supraspinatus strengthening may be beneficial.

Electromyographic analysis of the triceps surae muscle complex during achilles tendon rehabilitation program exercises.

BACKGROUND: Specific guidelines for therapeutic exercises following an Achilles tendon repair are lacking. HYPOTHESIS: A hierarchical progression of triceps surae exercises can be determined on the basis of electromyographic (EMG) activity. STUDY DESIGN: Randomized laboratory trial. METHODS: Bipolar surface electrodes were applied over the medial and lateral heads of the gastrocnemius as well as the soleus on 20 healthy lower extremities (10 participants, 27 ± 5 years old). Muscle activity was recorded during 8 therapeutic exercises commonly used following an Achilles repair. Maximal voluntary isometric contractions (MVICs) were also performed on an isokinetic device. The effect of exercise on EMG activity (% MVIC) was assessed using repeated measures analysis of variance with Bonferroni corrections for planned pairwise comparisons. RESULTS: Seated toe raises (11% MVIC) had the least amount of activity compared with all other exercises (P < 0.01), followed by single-leg balance on wobble board (25% MVIC), prone ankle pumps (38% MVIC), supine plantarflexion with red elastic resistance (45% MVIC), normal gait (47% MVIC), lateral step-ups (60% MVIC), single-leg heel raises (112% MVIC), and single-leg jumping (129% MVIC). CONCLUSION: There is an increasing progression of EMG activity for exercises that target the triceps surae muscle complex during common exercises prescribed in an Achilles tendon rehabilitation program. Seated toe raises offer relatively low EMG activity and can be utilized as an early rehabilitative exercise. In contrast, the single-leg heel raise and single-leg jumping should be utilized only during later-stage rehabilitation. CLINICAL RELEVANCE: EMG activity in the triceps surae is variable with common rehab exercises.

Reliability of shoulder range of motion comparing a goniometer to a digital level.

The clinical use of digital levels, for joint measurement, may be a viable alternative to standard goniometry. The purpose of this study was to determine the intra- and intertester reliability of a construction grade digital level compared to the standard universal goniometer for measurements for active assisted shoulder range of motion (ROM). Two experienced physical therapists measured shoulder flexion, external rotation (ER), and internal rotation (IR) ROM bilaterally, on two different occasions, in 20 patients (9 males, 11 females, 18-79 years old) with unilateral shoulder pathology, using a goniometer and a digital level. Relative reliability was assessed by using intraclass correlation coefficients (ICC), and absolute reliability was assessed by using 95% limits of agreement (LOA). Intratester ICCs ranged from 0.91 to 0.99, and LOA ranged from 3 degrees to 9 degrees for measurements made with the goniometer and digital level. Intertester ICCs ranged from 0.31 to 0.95, and LOA ranged from 6 degrees to 25 degrees . For the comparison of goniometric vs. digital level ROM, ICCs ranged from 0.71 to 0.98. ER and IR ROM were 3-5 degrees greater for the digital level than the goniometer (p < 0.01). Goniometric vs. digital level LOA ranged from 6 degrees to 11 degrees for shoulder flexion. Both measurement techniques had excellent intratester reliability, but for intertester reliability ICCs were 20% lower and LOA were 2.3 times higher than intratester values. Reliability estimates were similar between the digital level and the goniometer. However, because glenohumeral rotation was 3-5 degrees greater for the digital level than the goniometer (systematic error), the two methods cannot be used interchangeably. On the basis of the average intratester LOA for the goniometer and the digital level, a change of 6-11 degrees is needed to be certain that true change has occurred. For comparison of measures made by two different therapists, a change is of 15 degrees is required to be certain a true change has occurred. A digital level can be used to reliably measure shoulder ROM but should not be used interchangeably with a standard goniometer.

Adaptations in single-leg hop biomechanics following anterior cruciate ligament reconstruction.

When a patient performs a clinically normal hop test based on distance, it cannot be assumed that the biomechanics are similar between limbs. The objective was to compare takeoff and landing biomechanics between legs in patients who have undergone anterior cruciate ligament reconstruction. Kinematics and ground reaction forces were recorded as 13 patients performed the single-leg hop on each leg. Distance hopped, joint range of motion, peak joint kinetics and the peak total extensor moment were compared between legs during both takeoff and landing. Average hop distance ratio (involved/noninvolved) was 93 ± 4%. Compared to the noninvolved side, knee motion during takeoff on the involved side was significantly reduced (P = 0.008). Peak moments and powers on the involved side were lower at the knee and higher at the ankle and hip compared with the noninvolved side (Side by Joint P = 0.011; P = 0.003, respectively). The peak total extensor moment was not different between legs (P = 0.305) despite a decrease in knee moment and increases in ankle and hip moments (Side by Joint P = 0.015). During landing, knee motion was reduced (P = 0.043), and peak power absorbed was decreased at the knee and hip and increased at the ankle on the involved side compared to the noninvolved side (P = 0.003). The compensations by other joints may indicate protective adaptations to avoid overloading the reconstructed knee.

Correction of posterior shoulder tightness is associated with symptom resolution in patients with internal impingement.

BACKGROUND: Glenohumeral internal rotation deficit (GIRD) and posterior shoulder tightness have been linked to internal impingement. PURPOSE: To determine if improvements in GIRD and/or decreased posterior shoulder tightness are associated with a resolution of symptoms. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Passive internal rotation and external rotation (ER) range of motion (ROM) at 90 degrees of shoulder abduction and posterior shoulder tightness (cross-chest adduction in side lying) were assessed in 22 patients with internal impingement (11 men, 11 women; age 41 +/- 13 years). Treatment involved stretching and mobilization of the posterior shoulder. The Simple Shoulder Test (SST) was administered on initial evaluation and discharge. Changes in GIRD, ER ROM, and posterior shoulder tightness were compared between patients with complete resolution of symptoms versus patients with residual symptoms using independent t tests. RESULTS: Patients had significant GIRD (35 degrees), loss of ER ROM (23 degrees), and posterior shoulder tightness (35 degrees) on initial evaluation (all P < .01). Physical therapy (7 +/- 2 weeks; range, 3-12 weeks) improved GIRD (26 degrees +/- 14 degrees; P < .01), ER ROM loss (14 degrees +/- 20 degrees), and posterior shoulder tightness (27 degrees +/-19 degrees). The SST improved from 5 +/- 3 to 11 +/- 1 (P < .01). A greater improvement in posterior shoulder tightness was seen in patients with complete resolution of symptoms (n = 12) compared with patients with residual symptoms (35 degrees vs 18 degrees; P < .05). Improvements in GIRD and ER ROM loss were not different between groups (GIRD, 25 degrees vs 28 degrees, P = .57; ER ROM, 14 degrees vs 15 degrees, P = .84). CONCLUSION: Resolution of symptoms after physical therapy treatment for internal impingement was related to correction of posterior shoulder tightness but not correction of GIRD.

Muscle strength and range of motion in adolescent pitchers with throwing-related pain: implications for injury prevention.

BACKGROUND: A high prevalence of throwing-related shoulder and elbow pain has been documented in adolescent baseball pitchers. HYPOTHESIS: Pitchers with a history of throwing-related pain will have weakened dominant-arm posterior shoulder musculature and greater dominant-arm glenohumeral total range of motion (ROM) loss compared with pitchers without throwing-related pain. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-three adolescent pitchers (age 15.7 +/- 1.4 years) were tested. Twelve pitchers had throwing-related pain in the prior season and were currently symptom-free, while the remaining 11 pitchers had no such history of pain. Internal and external rotation ROM and muscle strength (lower trapezius, middle trapezius, rhomboids, latissimus dorsi, supraspinatus, internal rotators, external rotators) were measured bilaterally. Dominant versus nondominant differences in ROM and strength were compared between pitchers with and without throwing-related pain. RESULTS: As a whole, the group of 23 pitchers had a loss of internal rotation ROM (13 degrees +/- 10 degrees , P < .001) and gain in external rotation ROM (11 degrees +/- 10 degrees , P < .001) on the dominant versus nondominant arm, with no effect on total ROM (2 degrees +/- 7 degrees loss, P = .14). There was no difference in bilateral comparison of total ROM between pitchers with and without throwing-related pain. Dominant versus nondominant muscle strength was lower (P < .05) for the pain group versus nonpain group for the middle trapezius (7% +/- 19% vs 22% +/- 12%) and supraspinatus (-4% +/- 27% vs 14% +/- 14%) and higher (P < .05) for the internal rotators (19% +/- 14% vs 6% +/- 12%). CONCLUSION: Throwing-related pain in this population may be due to the inability of weakened posterior shoulder musculature to tolerate stress imparted on it by adaptively strengthened propulsive muscles. CLINICAL RELEVANCE: Selective posterior shoulder strengthening may be indicated in rehabilitative and injury prevention programs for adolescent pitchers.

Effect of knee flexion angle on Achilles tendon force and ankle joint plantarflexion moment during passive dorsiflexion.

Early mobilization exercises are advocated following Achilles tendon (AT) repair, but forces on the repair during passive range of motion are unknown. The extent to which these forces change with flexion of the knee is also not known. Estimated AT forces were measured using 3 models: cadaveric, uninjured subjects, and in both legs of subjects 6 weeks following unilateral AT repair. For cadaveric testing, estimated AT force was recorded using a force transducer while cycling the ankle from 10 degrees plantarflexion to maximum dorsiflexion at 3 different knee flexion angles (0 degrees , 45 degrees , and 90 degrees ). For in vivo testing, subjects were seated in an isokinetic dynamometer, and their ankles passively cycled from plantarflexion to dorsiflexion with the knee extended and flexed 50 degrees . Passive plantarflexion moment recorded by the dynamometer was converted to AT force by estimating the AT moment arm. In the cadaveric model, knee flexion reduced estimated AT forces during dorsiflexion by more than 40% (P < .036). In vivo testing showed that estimated AT force was reduced in knee flexion in healthy subjects (P < .001) and in the uninvolved leg AT repair subjects (P = .021), but not in the AT repaired leg (P = .387). Normal AT showed a marked reduction in estimated AT force with knee flexion which was not present in repaired AT. This could be because of elongation of the repair, causing more slack in the tendon that would need to be taken up before force transmission occurs. ACFAS Level of Clinical Evidence: 4.