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Background: Creatine supplementation has been shown to augment training-induced strength gains. The purpose of this study was to examine the effect of creatine supplementation on recovery of muscle strength after anterior cruciate ligament (ACL) reconstruction. Hypothesis: Creatine supplementation will facilitate strength gains after AOL reconstruction. Study Design: Double-blind, prospective, and randomized clinical trial. Methods: Sixty patients were randomized into creatine or placebo groups. Quadriceps and hamstring strength and power were measured isokinetically. Hip flexor, abductor, and adductor strengths were measured with a handheld dynamometer prior to surgery and at 6 weeks, 12 weeks, or 6 months after surgery. Results: From 6 weeks to 12 weeks after surgery, there were significant increases in strength on the involved side for knee extension (47%), knee flexion (27%), hip flexion (20%), hip abduction (9%), and hip adduction (17%). These strength improvements were unaffected by creatine supplementation with similar effects in the creatine and placebo groups. From 6 weeks to 12 weeks after surgery, there were significant increases in power on the involved side for knee extension (46%) and knee flexion (26%), but these effects were not affected by creatine supplementation. At 6 months, creatine supplementation did not affect outcome as measured by the single leg hop test for distance or the knee outcome score. Conclusions: The results demonstrate that patients do not benefit from creatine supplementation during the first 12 weeks of rehabilitation after AOL reconstruction. [ABSTRACT FROM AUTHOR]

Presents a study which determined whether hip muscle strength and flexibility contribute to the incidence of adductor muscle strains in hockey players. Risk of hockey players for noncontact muscoskeletal injuries; Methodology; Results and discussion.

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 x side x 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. [ABSTRACT FROM AUTHOR]

Purpose: Quadriceps weakness is common after anterior cruciate ligament reconstruction (ACLR). Limited neuromuscular activation may have a role in the weakness. The purpose of this study was to use peripheral magnetic stimulation to measure changes in quadriceps inhibition in patients during rehabilitation from ACLR.Methods: Ten patients (7M/3F; age 35 ± 8 years; BMI 26.0 ± 4.8 kg/m2) who had ACLR with patellar tendon autograft were recruited. At 3 and 6 months postoperatively, patients' knee extension peak torque was measured during maximum voluntary isometric contraction (MVIC), magnetic stimulation-evoked contraction, and MVIC augmented with superimposed burst magnetic stimulation to the femoral nerve. All tests were done bilaterally at 30° and 65° of knee flexion on a dynamometer. Central activation ratio was calculated by dividing the peak torque before stimulation by peak torque after stimulation.Results: Patients had marked deficits in MVIC, with improvement from 3 to 6 months that was more apparent at 65° versus 30° (P < 0.05). There was significant deficit in stimulation-evoked torque on the involved side that diminished over time, and this change occurred differently between the two angles (P < 0.05). Central activation ratio was lower on the involved side versus the noninvolved side and this effect was more prominent at 3 versus 6 months: combining the angles, mean central activation ratio on the involved and noninvolved sides, respectively, was 91.4 ± 7.6% and 97.5 ± 5.3% at 3 months, and 93.0 ± 7.8% and 95.8 ± 6.8% at 6 months.Conclusions: At 3 and 6 months after ACLR, there were significant deficits in quadriceps strength and activation. Quadriceps activation levels were high (> 90%) for both sides at both time points. The substantial strength deficits at this postoperative period may be largely due to muscle atrophy with limited contribution from central inhibition. Rehabilitation interventions to normalize quadriceps strength should emphasize hypertrophic stimuli as opposed to neuromuscular activation strategies.Level Of Evidence: II, prospective cohort study. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background:Monitoring pitch count is standard practice in minor league baseball but not in softball because of the perception that fast-pitch softball pitching is a less stressful motion.Purpose:To examine muscle fatigue after fast-pitch softball performances to provide an assessment of performance demand.Study Design:Descriptive laboratory study.Methods:Bilateral strength measurements (handheld dynamometer) were made on 19 female softball pitchers (mean age [±SD], 15.2 ± 1.2 years) before and after pitching a game (mean number of pitches, 99 ± 21; mean innings pitched, 5 ± 1). A total of 20 tests were performed on the dominant and nondominant sides: forearm (grip, wrist flexion/extension, pronation/supination, elbow flexion/extension), shoulder (flexion, abduction/adduction, external/internal rotation, empty can test), scapula (middle/lower trapezius, rhomboid), and hip (hip flexion/extension, abduction/adduction). Fatigue (percentage strength loss) was categorized based on bilateral versus unilateral presentation using paired t tests: bilateral symmetric (significant on dominant and nondominant and not different between sides), bilateral asymmetric (significant on dominant and nondominant but significantly greater on dominant), unilateral asymmetric (significant on dominant only and significantly greater than nondominant), or unilateral equivocal (significant on dominant only but not different from nondominant).Results:Bilateral symmetric fatigue was evident for all hip (dominant, 19.3%; nondominant, 15.2%) and scapular tests (dominant, 19.2%; nondominant, 19.3%). In general, shoulder tests exhibited bilateral asymmetric fatigue (dominant, 16.9%; nondominant, 11.6%). Forearm tests were more variable, with bilateral symmetric fatigue in the elbow flexors (dominant, 22.5%; nondominant, 19.2%), and wrist flexors (dominant, 21.6%; nondominant, 19.0%), bilateral asymmetric fatigue in the supinators (dominant, 21.8%; nondominant, 15.5%), unilateral asymmetric fatigue in the elbow extensors (dominant, 22.1%; nondominant, 11.3%), and unilateral equivocal fatigue in the pronators (dominant, 18.8%; nondominant, 15.2%) and grip (dominant, 11.4%; nondominant, 6.6%). The mean (±SD) pitch velocity was 49 ± 4 mph, with a small loss of velocity from the first to last inning pitched (3.4% ± 5.0%, P < .01).Conclusion:Fast-pitch softball pitching resulted in profound bilateral fatigue in the hip and scapular muscles, with more selective fatigue in the shoulder and arm muscles.Clinical Relevance:These findings emphasize the importance of strength in the proximal musculature to provide a stable platform for the arm to propel the ball. [ABSTRACT FROM AUTHOR]

The article discusses research which investigated shoulder and elbow injury risk factors in high school baseball pitchers. Topics explored include the measurement of pre-baseball season strength and range of motion in players' throwing arm, the evaluation of glenohumeral internal and external rotation and posterior shoulder tightness, and the statistical calculation of relative risk factors gathered.

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° ± 10°, P < .001) and gain in external rotation ROM (11° ± 10°, P < .001) on the dominant versus nondominant arm, with no effect on total ROM (2° ± 7° 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. [ABSTRACT FROM AUTHOR]

Background: Separation of tendon ends after Achilles tendon repair may affect the tendon repair process and lead to postoperative end-range plantarflexion weakness. Hypothesis; Patients will have disproportionate end-range plantarflexion weakness after Achilles tendon repair. Study Design: Descriptive laboratory study. Methods: Four-strand core suture repairs of Achilles tendon were performed on 1 female and 19 male patients. Postoperatively, patients were nonweightbearing with the ankle immobilized for 4 weeks. Plantarflexion torque, dorsiflexion range of motion, passive joint stiffness, toe walking, and standing single-legged heel rise (on an incline, decline, and level surface) were assessed after surgery (mean, 1.8 years postoperative; range, 6 months–9 years). Maximum isometric plantarflexion torque was measured at 20° and 10° of dorsiflexion, neutral, and 10° and 20° of plantar flexion. Percentage strength deficit (relative to noninvolved leg) was computed at each angle. Passive dorsiflexion range of motion was measured goniometrically. Passive joint stiffness was computed from increase in passive torque between 10° and 20° of dorsiflexion, before isometric contractions. Results: Significant plantarflexion weakness was evident on the involved side at 20° and 10° of plantar flexion (34% and 20% deficits, respectively; P < .001), with no torque deficits evident at other angles (6% at neutral, 3% at 10° of dorsiflexion, 0% at 20° of dorsiflexion). Dorsiflexion range of motion was not different between involved and noninvolved sides (P = .7). Passive joint stiffness was 34% lower on the involved side (P < .01). All patients could perform an incline heel rise; 14 patients could not perform a decline heel rise (P < .01). Conclusion: Disproportionate weakness in end-range plantar flexion, decreased passive stiffness in dorsiflexion, and inability to perform a decline heel rise are evident after Achilles tendon repair. Possible causes include anatomical lengthening, increased tendon compliance, and insufficient rehabilitation after Achilles tendon repair. Clinical Relevance: Impairments will have functional implications for activities (eg, descending stairs and landing from a jump). Weakness in end-range plantar flexion may be an unrecognized problem after Achilles tendon repair. [ABSTRACT FROM AUTHOR]

Background: Previous studies have estimated joint torques and electromyogram activity associated with the pitching motion. Although previous studies have investigated the influence of extended pitching (fatigue) on kinematic and kinetic parameters, no attempts have been made to quantify the fatigue associated with a pitching performance. Purpose: Considering previous investigations on muscle activity during pitching, this study investigated muscle fatigue in upper and lower extremity muscle groups after a pitching performance. Study Design: Descriptive laboratory study. Methods: Thirteen baseball pitchers from 4 universities and 1 independent minor league team were tested before and after 19 games. Pitchers threw an average of 99 pitches during an average of 7 innings. Shoulder, scapular, and lower extremity muscle strengths were assessed using a handheld dynamometer before and after the pitching performances. Results: Baseline strength tests revealed that the pitching arm was 12% weaker (P = .02) in the empty can test (supraspinatus) compared to the contralateral side. Postgame shoulder strength tests revealed selective fatigue of 15% in shoulder flexion (P = .02), 18% fatigue in internal rotation (P = .03), and 11% fatigue in shoulder adduction (P = .01). Minimal fatigue was noted in the empty can test, scapular stabilizers, and hip musculature. Conclusions: A trend toward significant baseline strength in internal rotation together with significant selective postgame fatigue on internal rotation of the dominant upper extremity indicate that the internal rotators experience a high performance demand during pitching. Weakness in the empty can test on the dominant arm combined with minimal postgame fatigue was surprising given that studies and injury patterns have indicated a high performance demand on the supraspinatus during pitching. [ABSTRACT FROM AUTHOR]

Presents a study which examined whether preoperative and early postoperative measures of quadriceps muscle strength were predictive of residual quadriceps muscle weakness. Methodology; Results; Discussion.