Jump-Landing Biomechanics

"Certain athletes are at higher risk of knee pain and non-contact knee injury than others."

The above statement is well known but unfortunately, not many of us know exactly why. Thankfully, the American Journal of Sports Medicine gave us some input into the biomechanical reasons some athletes are at risk of patellofemoral pain syndrome (sorry Mike) and potentially at risk of non-contact ACL injury. The information below is taken from two VERY recently published papers from the large scale Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) study. This study examined the biomechanical variables involved in a jump-landing-rebound task.

​Biomechanical Factors Potentially Involved with Risk of Non-Contact ACL Injury

• Lower knee and hip flexion motion (saggital plane kinematics)
• Higher knee valgus and hip adduction angle (frontal plane kinematics)
• Greater internal knee and hip internal rotation moment (transverse plane kinematics)
• Greater internal knee and hip extension moment and anterior tibial shear force (saggital plane kinetics)
• Greater internal knee valgus and hip adduction moment (frontal plane kinetics)
• Greater vertical ground reaction force
• Women

Biomechanical Factors Potentially Involved with Patellofemoral Pain Syndrome

• Decreased hip abduction, knee flexion, and knee extension strength
• Lower knee extension moments
• Greater navicular drop
• Decreased peak knee flexion angle
• Women

This is what I think:

• Women are more important than biomechanical factors (they are actually more important than many things in life)
• Athletes need to learn to absorb the landing (land with the toes and roll back onto the heels in one fluid motion)
• Athletes need to eccentrically control the lower extremity from collapsing in when landing (don’t land knock-kneed)
• Feet should be shoulder width apart
• Spine should be neutral and the core should be stiff
• Athletes need to spend some time on the glute/posterior-chain eccentrics

​The preceeding information was derived from the two most recent issues of AJSM. It is strongly suggested that for a complete understanding, readers view the papers in their entirety as Padua et al was based on validating the Landing Error Scoring System and Boling et al interestingly found higher hip ER strength and lower ground reaction forces as risk factors.