Limited hip and knee flexion during landing is associated with increased frontal plane knee motion and moments

Abstract

Background It has been proposed that female athletes who limit knee and hip flexion during athletic tasks rely more on the passive restraints in the frontal plane to deceleration their body center of mass. This biomechanical pattern is thought to increase the risk for anterior cruciate ligament injury. To date, the relationship between sagittal plane kinematics and frontal plane knee motion and moments has not been explored. Methods Subjects consisted of fifty-eight female club soccer players (age range: 11 to 20 years) with no history of knee injury. Kinematics, ground reaction forces, and surface electromyography were collected while each subject performed a drop landing task. Subjects were divided into two groups based on combined sagittal plane knee and hip flexion angles during the deceleration phase of landing (high flexion and low flexion). Findings Subjects in the low flexion group demonstrated increased knee valgus angles (P = 0.02, effect size 0.27), increased knee adductor moments (P = 0.03, effect size 0.24), decreased energy absorption at the knee and hip (P = 0.02, effect size 0.25; and P< 0.001, effect size 0.59), and increased vastus lateralis EMG when compared to subjects in the high flexion group (P = 0.005, effect size 0.35). Interpretation Female athletes with limited sagittal plane motion during landing exhibit a biomechanical profile that may put these individuals at greater risk for anterior cruciate ligament injury.

The Effect of Arm Position on Lower Extremity Kinematics during a Single Limb Drop Landing: A Preliminary Study

“…When landing with a decrease in hip flexion, there tends to be an emphasis on the use of knee extensors (quadriceps) instead of the hip extensors (hamstrings and gluteus maximus) to attenuate the ground reaction forces [10]. Since the quadriceps produce an anteriorly directed shear force on the proximal tibia, which contributes to ACL loading, whereas the hamstrings produce a posteriorly directed shear force on the proximal tibia, which protects the ACL, this finding could be of particular importance.…”

“…A more upright or "stiff" landing movement pattern, characterised by reduced flexion of the hip and knee joints coupled with increased ankle dorsiflexion [1], has been proposed to increase the risk of ACL injury. This may be due to these kinematic factors increasing the ground reaction force and reducing the ability of the hamstring muscles to prevent anterior shear force acting on the proximal end of the tibia [10], which in turn is likely to increase the strain on the ACL [11]. Knee valgus motion, caused by the excessive hip adduction and internal rotation whereby these movements combine to cause the tibia to abduct and the foot to pronate when the foot is fixed to the floor [12], has also been shown to increase the relative load on the ACL [13].…”

The Effect of Foot Landing Type on Lower-extremity Kinematics, Kinetics, and Energy Absorption during Single-leg Landing

“…In other words, since the results of our study show greater knee and ankle flexion for forefoot landing, the knee extensors and ankle plantarflexors are able to continue absorbing energy, reducing the load acting on the joints; conversely, for rearfoot landing, more restricted flexion of the knee and ankle joints impairs the ability to properly absorb the impact of the GRF, which is larger than in forefoot landing, resulting in a higher risk of knee or ankle injury. Furthermore, previous studies have reported that a hard landing, in which the peak knee flexion is small, shows greater activation of the vastus lateralis than a soft landing, in which the peak knee flexion is larger (Lee et al, 2001;Pollard, Sigward, & Powers, 2010). Thus, in rearfoot landing where there is greater knee extension than in forefoot landing, the large quadriceps femoris muscles are expected to be more active, pulling the tibia anteriorly and causing significant forces and strain on the ACL, which in turn could increase the risk of ACL injury (Li et al, 1999;Pandy & Shelburne, 1997).…”

Neuromuscular Retraining in Female Adolescent Athletes: Effect on Athletic Performance Indices and Noncontact Anterior Cruciate Ligament Injury Rates

“…Shultz et al [15] noted the importance of feedback that emphasizes correct form and technique, along with positive motivation of the athlete during training. We believe supervision is a vital component, especially in athletes that demonstrate potentially dangerous landing and cutting techniques that are believed to increase the risk of a noncontact ACL injury, such as low knee and hip flexion angles and landing flatfooted, with the foot far away from the center of body mass [80][81][82][83]. During training, athletes were constantly reminded to land softly with high knee flexion when jumping, to decelerate using small quiet steps, and to stop during sprinting drills with as little impact as possible.…”