Hamstring extensibility and transverse plane knee control relationship in athletic women

Abstract

Athletic women are at particular risk for sustaining a non-contact anterior cruciate ligament (ACL) injury. The hamstrings are vital to providing dynamic knee motion control in the sagittal and transverse planes during running stance, and some have suggested this function is enhanced when they are less extensible. This study attempted to determine the correlational relationships between hamstring extensibility and transverse plane knee kinematics and from these data to describe the dynamic transverse plane knee motion control capabilities of the hamstrings. Twenty normal athletic women (mean +/- SD; aged 21 +/- 1.6 years; height 163.3 +/- 5.7 cm; weight 60.1 +/- 3.6 kg) were evaluated for active hamstring extensibility and transverse plane knee kinematic relationships during crossover-cut stance phase. Following crossover-cut training (3 weeks) using the left (preferred) lower extremity as the stance limb, hamstring extensibility was measured. Following this, subjects were fitted with 9 retroreflective markers denoting the local segmental coordinate systems (3 markers each) of the left foot, leg and thigh. Kinematic (3-dimensional, four phase-locked cameras, 200 Hz) knee and ankle data were sampled and analyzed. Descriptive statistics and Pearson correlations between hamstring extensibility and knee and ankle kinematic variables were calculated. Statistical significance was set at P < or = 0.05 with Bonferroni adjustments. Hamstring extensibility (12 degrees +/- 8 degrees terminal extension) revealed low but significant positive correlations with tibial external rotation (6 degrees +/- 10.7 degrees) at heelstrike (19.3 degrees +/- 8.5 degrees knee flexion) (r = 0.62, P = 0.004) and tibial internal rotation (-13 degrees +/- 8.4 degrees) at peak knee flexion (57.8 degrees +/- 9.3 degrees) following heelstrike (r = 0.47, P = 0.01). Increased hamstring extensibility resulted in increased tibial external rotation at heelstrike and decreased tibial internal rotation at peak knee flexion. Increased hamstring extensibility may improve knee extensor efficiency at heelstrike by enabling greater tibial external rotation and protect the ACL at peak knee flexion by decreasing the tibial internal rotation magnitude.

Hamstrings Stiffness and Landing Biomechanics Linked to Anterior Cruciate Ligament Loading

“…35 Given that the hamstrings attach posteriorly on the medial and lateral aspects of the shank segment, they can influence 3-dimensional knee-joint loading. 8,[36][37][38] Hamstrings activity can limit frontal-plane knee loading during controlled loading conditions 39,40 and during static 41 and dynamic tasks. 42 Cadaveric data also have indicated that hamstrings force can limit ACL loading attributable to anterior tibial shear force.…”

Gender Differences in the Kinematics of Unanticipated Cutting in Young Athletes

“…Increased ankle eversion may be a potential factor related to the gender differences found in ACL injury rates. Increased valgus knee stress and a preloading effect on the ACL may result from excessive eversion or pronation (18,26). This is may be due in part to a coupling of foot eversion and internal tibial rotation (3,22.26).…”

The relationships between active extensibility, and passive and active stiffness of the knee flexors

“…Musculotendinous stiffness may have implications for joint stability from both mechanical [21,24,27,31,32] and neural [11,14,19,34] perspectives. The knee flexors are appropriately positioned to provide resistance to anterior tibial translation and rotation relative to the femur, and their associated stiffness may serve as a protective mechanism for the anterior cruciate ligament (ACL).…”