Understanding Jumping Mechanics

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With Chicago summer upon us, jumping sports like beach volleyball, basketball and tennis are in full swing, and a legion of athletes of all ages worry about their knees. If you’ve played a sport that involved jumping at any point in your life, you’ve probably heard a coach or trainer tell you to “watch your jump mechanics.” As a physical therapist, one of the first things we look at with injured athletes is their form during a jump landing and a deep squat. But what does that mean exactly?
A recent report in the Journal of Orthopaedic and Sports Physical Therapy (JOSPT) looked at real-time feedback versus post-performance feedback on jump mechanics, and good news, those participants who received only post-performance feedback saw equal improvements, so no need for fancy setups to analyze your jumps, just a little bit of self-awareness.
Here’s five key points to look for when considering your jumping:
1. Land Softly
Landing softly can help to decrease impact loading / vertical ground reaction force, which can decrease how far your shin bone shifts forward, which can decrease risk for ACL injury.
2. Bend Your Knees and Hips
In a 2005 study, there was a correlation between decreased knee flexion and ACL injury in female athletes. Another study cued this as landing with your ‘knees over your toes’, which improved peak knee flexion angles.
3. Land with Both Feet at the Same Time
Landing asymmetrically can cause undue force through one foot/knee/ankle.
4. Don’t Let Your Knees Buckle In or Out
Landing with your feet parallel and your knees facing forward, like headlights, helps to reduce impact stress and allows both the inner and outer knee to absorb force. In an article looking at videos from 39 basketball ACL tears, doctors found that athletes demonstrated dynamic knee valgus (buckling inward) in many of the cases.
5. Land with Feet Shoulder Width Apart
Landing with your knees too wide or too narrow can increase the tendency to buckle. If you’re landing on one foot, land with that foot in the middle, underneath your body mass.
Worried about doing all that practice for nothing? A 2001 JOSPT study showed that subjects given one session of jump training with feedback showed improvement not only on a test repeated in two minutes after training, but also one week later. The brain is a powerful thing!

References: Ericksen H, Thomas A, Gribble P, Doebel S, Pietrosimone B. Immediate Effects of Real-Time Feedback on Jump-Landing Kinematics. J Orthop Sports Phys Ther. 2015;45(2):112-118. doi:10.2519/jospt.2015.4997.
Hewett TE, Myer GD, Ford KR, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study. Am J Sports Med. 2005;33:492–501. http://dx.doi.org/10.1177/0363546504269591
Mothersole G, Cronin J, Harris N. Jump-Landing Program for Females. Strength and Conditioning Journal. 2014;36(4):52-64. doi:10.1519/ssc.0000000000000078.
Onate J, Guskiewicz K, Sullivan R. Augmented Feedback Reduces Jump Landing Forces. J Orthop Sports Phys Ther. 2001;31(9):511-517. doi:10.2519/jospt.2001.31.9.511.