Running Biomechanics and Clinical Features Among Adolescent Athletes With Lower Leg Chronic Exertional Compartment Syndrome.

OBJECTIVE: To compare clinical measures between patients with chronic exertional compartment syndrome (CECS) and healthy controls and evaluate running biomechanics, physical measurements, and exertional intracompartmental (ICP) changes in adolescent athletes with lower leg CECS. DESIGN: Cross-sectional case-control study. SETTING: Large tertiary care hospital and affiliated injury prevention center. PARTICIPANTS: Forty-nine adolescents with CECS (39 F, 10 M; age: 16.9 ± 0.8 years; body mass index (BMI): 23.1 ± 2.9 kg/m 2 ; symptom duration: 8 ± 12 months) were compared with 49 healthy controls (39 F, 10 M; age: 6.9 ± 0.8 years; BMI: 20.4 ± 3.7 kg/m 2 ). INTERVENTIONS: All participants underwent gait analyses on a force plate treadmill and clinical lower extremity strength and range of motion testing. Patients with chronic exertional compartment syndrome underwent Stryker monitor ICP testing. MAIN OUTCOME MEASURES: Symptoms, menstrual history, and ICP pressures of the patients with CECS using descriptive statistics. Mann-Whitney U and χ 2 analyses were used to compare CECS with healthy patients for demographics, clinical measures, and gait biomechanics continuous and categorical outcomes, respectively. For patients with CECS, multiple linear regressions analyses were used to assess associations between gait biomechanics, lower extremity strength and range of motion, and with ICP measures. RESULTS: The CECS group demonstrated higher mass-normalized peak ground reaction force measures (xBW) compared with controls (0.21 ± 0.05 xBW ( P < 0.001) and were more likely to have impact peak at initial contact ( P = 0.04). Menstrual dysfunction was independently associated with higher postexertion ICP (ß = 14.6; P = 0.02). CONCLUSIONS: The CECS group demonstrated increased total force magnitude and vertical impact transient peaks. In women with CECS, menstrual dysfunction was independently associated with increased postexertion ICP. These biomechanical and physiological attributes may play a role in the development of CECS.

Adolescent and young adult hip and knee strength profiles relate to running gait biomechanics.

OBJECTIVES: Compare and assess relationships between strength and running biomechanics among healthy adolescents and young adult males and females. DESIGN: Retrospective cohort. SETTING: Clinic. PARTICIPANTS: 802 healthy participants (570 F, 232 M; 16.6 ± 2.3 years). MAIN OUTCOME MEASURES: Mass-normalized knee flexor and extensor strength, hip adductor and abductor strength, hamstrings-to-quadriceps (H:Q), and abductor-to-adductor (Abd:Add) ratios were obtained using hand-held dynamometry. Mass-normalized peak vertical ground reaction force (vGRF), %stance, cadence, and stride length were obtained using an instrumented treadmill. Multivariate analyses of variance were used to compare strength and biomechanics across ages and sexes. Linear regressions were used to assess the relationships between strength and biomechanics, accounting for speed, age, and sex. Independent t-tests were used to compare strength between strength ratio profiles. RESULTS: Strength and running biomechanics significantly differed between sexes (p-range: <0.001-0.05) and age groups (p-range: <0.001-0.02). Strength and strength ratios were significantly associated with increased cadence (p-range:0.001-0.04) and stride lengths (p-range:0.004-0.03), and decreased vGRF (p < 0.001). Lower H:Q ratios had significantly lower strength measures (p < 0.001). Higher Abd:Add ratios had significantly increased abductor strength (p < 0.001). CONCLUSIONS: Strength and running biomechanics differed by sexes and ages. Hip and knee strength and strength ratios were related to select spatiotemporal and kinetic biomechanical features.

The Effect of Stride Length and Lateral Pelvic Tilt on Elbow Torque in Youth Baseball Pitchers.

High elbow torque during a pitch may contribute to injury risk. Our objective was to determine the pitch mechanics associated with elbow varus torque in youth baseball pitchers. Eighteen male youth pitchers (age = 15.5 ± 1.6 years) threw 3 fastballs and 3 change-ups from a windup position while undergoing 3-dimensional kinematic analysis. Independent variables included ball release point distance, stride length, lateral pelvic tilt, and ball velocity. Two multiple regression models, separated by pitch type (fastball, change-up) were used to determine the association of independent variables with peak varus torque at the elbow. Fastball and change-up regression models indicated that stride length (ß = 0.301, p = .015; ß = 0.46, p < .001, respectively) and lateral pelvic tilt (ß = -0.50, p < .001; ß = -0.25, p = .04, respectively) were significantly associated with peak elbow varus torque. During fastballs, pitch velocity was significantly associated with peak elbow varus torque (ß = 0.38, p = .002), while release point distance was significantly associated with peak elbow varus torque during change-ups (ß = -0.33, p = .015). Youth pitchers with longer strides and less lateral pelvic tilt demonstrated greater elbow torque regardless of pitch type, while the association of ball velocity and release point to elbow varus torque was dependent on pitch type.

Performance Metrics in Professional Baseball Pitchers before and after Surgical Treatment for Neurogenic Thoracic Outlet Syndrome.

BACKGROUND: High-performance throwing athletes may be susceptible to the development of neurogenic thoracic outlet syndrome (NTOS). This condition can be career-threatening but the outcomes of treatment for NTOS in elite athletes have not been well characterized. The purpose of this study was to utilize objective performance metrics to evaluate the impact of surgical treatment for NTOS in Major League Baseball (MLB) pitchers. METHODS: Thirteen established MLB pitchers underwent operations for NTOS between July 2001 and July 2014. For those returning to MLB, traditional and advanced (PitchF/x) MLB performance metrics were acquired from public databases for various time-period scenarios before and after surgery, with comparisons made using paired t-tests, Wilcoxon matched-pair signed-rank tests, and Kruskal-Wallis analysis of variance. RESULTS: Ten of 13 pitchers (77%) achieved a sustained return to MLB, with a mean age of 30.2 ± 1.4 years at the time of surgery and 10.8 ± 1.5 months of postoperative rehabilitation before the return to MLB. Pre- and postoperative career data revealed no significant differences for 15 traditional pitching metrics, including earned run average (ERA), fielding independent pitching, walks plus hits per inning pitched (WHIP), walks per 9 innings, and strikeouts to walk ratio (SO/BB). There were also no significant differences between the 3 years before and the 3 years after surgical treatment. Using PitchF/x data for 72 advanced metrics and 25 different time-period scenarios, the highest number of significant relationships (n = 18) was observed for the 8 weeks before/12 weeks after scenario. In this analysis, 54 (75%) measures were unchanged (including ERA, WHIP, and SO/BB) and 14 (19%) were significantly improved, while only 4 (6%) were significantly decreased (including hard pitch maximal velocity 93.1 ± 1.0 vs. 92.5 ± 0.9 miles/hr, P = 0.047). Six pitchers remained active in MLB during the study period, while the other 4 had retired due to factors or injuries unrelated to NTOS. CONCLUSIONS: Objective performance metrics demonstrate that pitchers returning to MLB after surgery for NTOS have had capabilities equivalent to or better than before treatment. Thoracic outlet decompression coupled with an ample period of postoperative rehabilitation can provide effective treatment for professional baseball pitchers with career-threatening NTOS.

Examination of Age-Related Differences on Clinical Tests of Postural Stability.

BACKGROUND: The modified Balance Error Scoring System (mBESS) and Y-Balance Test are common clinical measurements of postural control, but little is known about the effect of age on performance of these tasks. The purpose of this study was to examine how healthy child and adolescent athletes perform on 2 common clinical measurements of postural control. HYPOTHESIS: Younger athletes would demonstrate poorer postural control compared with older athletes. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Three hundred eighty-nine athletes between the ages of 10 and 18 years underwent an evaluation of postural control. Each participant completed the mBESS in the double-leg, single-leg, and tandem stances as well as the Y-Balance Test. Postural stability data were analyzed between age groups (10-12, 13-15, and 16-18 years) using univariate analyses of covariance. RESULTS: The youngest athletes (10-12 years) had a greater mean number of errors in the single-leg stance of the mBESS than the 13- to 15-year-old and 16- to 18-year-old athletes (3.8, 3, and 2.5 errors, respectively; P < 0.01). They also had greater right to left asymmetry compared with the 16- to 18-year-old athletes on the Y-Balance Test in the posterolateral (6.8 and 3.8 cm, respectively; P = 0.006) and posteromedial (5.3 and 3.6 cm, respectively; P = 0.014) directions of movement. CONCLUSION: Athletes between the ages of 10 and 12 years performed worse on the single-leg stance of the mBESS and demonstrated more asymmetry on the Y-Balance Test in the posterolateral and posteromedial directions compared with older athletes. CLINICAL RELEVANCE: In the absence of a baseline balance test for athletes younger than the age of 13 years, caution should be used in interpreting postural stability assessments, as age may be a modifying factor in performance.