ABSTRACT
BACKGROUND: Lower extremity sprain and strain injury constitutes a large percentage of lower extremity injuries experienced by soccer players. Yet, very limited data exists on the association between core strength and endurance and this injury. PURPOSE: The purpose of this study was to compare core muscle endurance and hip muscle strength between soccer players who experienced non-contact lower extremity sprain and/or strain injury during their season and those who did not. Additionally, the frequency of injury was correlated with core muscle endurance and hip strength, and endurance was used for predicting the risk for injury. STUDY DESIGN: Prospective cohort. METHODS: Twenty-one (35.59%) athletes experienced non-contact lower extremity sprain and/or strain injury during the season. Fifty-nine male athletes (mean age 20.92 ± 4.08 years, mass 77.34 ± 12.02 kg and height 1.79 ± 0.06m) were tested. Prior to the start of the season, prone-bridge, side-bridge, trunk flexion and horizontal back extension hold times were recorded for endurance assessment and peak hip abductor and external rotator isokinetic torques for strength assessment. RESULTS: Prone-bridge and side-bridge hold times were significantly longer in the non-injured players when compared with the times of the injured players (p=0.043 & 0.008 for the prone-bridge and side-bridge, respectively). There were significant negative correlations between the frequency of injury and both prone-bridge (r=-0.324, p=0.007) and side-bridge (r=-0.385, p=0.003) hold times. Logistic regression analysis revealed that side-bridge hold time was a significant predictor of injury (OR=0.956, CI=0.925-0.989). CONCLUSION: Soccer players with non-contact lower extremity sprain and/or strain have less core endurance than non-injured players. Reduced core endurance is associated with increased incidence of injury. Improving side-bridge hold time, specifically, may reduce the risk for injury. LEVEL OF EVIDENCE: 1b.
ABSTRACT
BACKGROUND: Laterally wedged insoles have controversial effect in treating medial compartment knee osteoarthritis. This study examined the effects of unilateral and bilateral use of insoles having medial arch supports and of different inclinations on the frontal plane external hip, knee, subtalar moments and pelvic alignment. METHODS: Kinetic and kinematic gait parameters were collected from 21 patients with primary medial knee osteoarthritis. The insoles' inclinations were 0, 6 and 11°, where each of the 6° and 11° was used once unilaterally and another bilaterally while the 0° was used bilaterally as a control. FINDINGS: The Multivariate Analysis of Variance revealed significant increase in the external subtalar eversion moment using either of the 6° or 11° laterally wedged vs the 0° non-wedged insole conditions (P=0.003). Moreover, there were significant increases in the external eversion moment using the 11° vs the 6° insole conditions (P<0.05). However, there were no significant differences for the remaining tested variables (P>0.05). The bivariate correlations revealed significant negative correlations between the subtalar eversion and knee adduction moments (r=-0.409, P=0.000) and the subtalar eversion and hip adduction moments (r=-0.226, P=0.049), and positive correlation between the hip and knee adduction moments (r=0.268, P=0.019). INTERPRETATION: The non-significant reduction in the external knee adduction moment may question the efficacy of using wedged insoles having medial arch supports in treating patients with medial knee osteoarthritis. Additionally, using such insoles did not produce appreciable mechanical effects on remote articulations as the hip and pelvis.
