05) were retained. Statistical analyses were performed using SPSS version 19.0 (SPSS Inc., Chicago, IL, USA). There were significant side-to-side differences for all variables assessed in all players (Table 1). Glenohumeral internal rotation ROM (t155 = −14.1, p < 0.0005, mean difference (md) = −8.4°) and infraspinatus muscle stiffness (t155 = −2.7, p = 0.008, md = −2.9°) were significantly less
on the dominant side compared to the non-dominant side. Humeral retrotorsion (t155 = 17.9, p < 0.0005, md = 15.7°), posterior capsule thickness (t155 = −8.0, p < 0.005, md = 0.01 cm), posterior deltoid muscle stiffness (t155 = −4.2, p < 0.0005, md = 3.2 N/cm), and teres minor muscle stiffness selleck chemicals (t155 = 2.0, p = 0.050, md = 1.4 N/cm) were significantly greater on the dominant side compared to the non-dominant side. The regression model for prediction of GIRD in all baseball players was statistically significant (R2 = 0.134, F(1, 156) = 24.0, p < 0.01) with only humeral retrotorsion difference included as a significant predictor (β = −0.243, t156 = −4.9, p < 0.01). A greater humeral retrotorsion side-to-side difference was associated with greater GIRD. The analysis was also performed on 47 high school baseball players who listed their
primary position as pitcher (age = 16.2 ± 1.3 year; height = 181.1 ± 5.9 cm; mass = 75.3 ± 10.5 kg). Side-to-side descriptive values and comparisons of pitchers are presented in Table 2. Galunisertib solubility dmso Of the Casein kinase 1 47 pitchers included in the analysis, 85% (40 pitchers) experienced GIRD, with less internal rotation ROM on the dominant side compared to the non-dominant side. Glenohumeral internal rotation ROM (t46 = −7.7, p < 0.0005, md = −9.3°)
was significantly less on the dominant side compared to the non-dominant side. Humeral retrotorsion (t46 = 10.7, p < 0.0005, md = 18.1°), posterior capsule thickness (t46 = −5.6, p < 0.005, md = 0.02 cm) and posterior deltoid muscle stiffness (t46 = 3.2, p = 0.002, md = 1.6 N/cm) were significantly greater on the dominant side compared to the non-dominant side. There were no significant differences in infraspinatus (p = 0.076) or teres minor (p = 0.208) muscle stiffness between limbs in athletes that listed pitcher as their primary position. The regression model for prediction of GIRD in baseball players whose primary position was as pitcher was statistically significant (R2 = 0.126, F(1, 46) = 6.50, p = 0.01) with only humeral retrotorsion difference remaining as a significant predictor (β = −0.254, t46 = −2.6, p = 0.01). A greater humeral retrotorsion side-to-side difference was associated with greater GIRD. The results of our study indicate that humeral retrotorsion is a significant contributor to GIRD in high school baseball players and pitchers, a finding that is in agreement with previous literature.12 In addition, previous research has linked greater humeral torsion values3 and 39 with altered ROM.