As a follow up to my first post on the importance of dorsiflexion (HERE), I wanted to follow up by quickly reviewing the research on the effects of decreased dorsiflexion during jump landings.
During a land from a jump all the joints of the lower extremity work together to dissipate the forces. This coupling within the lower extremity means that when someone with decreased dorsiflexion lands, they will also typically demonstrate decreased flexion at the knees and hips (Fong et al., 2011).
Decreased dorsiflexion has been associated with greater medial knee displacement during a drop landing task (Sigward et al., 2008). Hagins et al had participants in their study land onto an inclined surface to limit the amount of available dorsiflexion motion available. Posterior ground reaction forces during a drop landing onto an incline increased by 10% of participant’s bodweight compared to landing on a flat surface! This significant increase in posterior ground reaction forces increases the stress placed on the ACL which the authors suggest is from increased force required of the quadriceps. They suggest that this may lead to tears of the ACL (Hagins et al., 2007).
Athletes with decreased dorsiflexion range of motion also land with their plantar flexors (calves) in a more stretched position. This means they may overstress their plantarflexors, possibly leading to injuries to the Achilles tendon (Whitting et al, 2011).
Conclusion: When you consider this research applied to athletes such as basketball players, it really stresses the importance of dorsiflexion range of motion. Basketball players commonly have decreased dorsiflexion as the result of multiple ankle sprains. As they play and perform thousands of jump landings during the course of the season, they are at an increased injury risk secondary to their limited ankle motion.
“So the findings indicate that techniques designed to increase plantar-flexor extensibility and dorsiflexion ROM may attenuate ACL injury risk by placing the lower extremity in a position consistent with reduced ACL loading, thus decreasing the forces the lower extremity must absorb after ground contact (Fong et al., 2011).”
- Dorsiflexion capacity affects achilles tendon loading during drop landings. Whitting, Steele, McGhee, Munro. Med Sci Sports Exerc. 2011.
- Ankle-Dorsiflexion Range of Motion and Landing Biomechanics. Fong, Blackburn, Norcross, McGrath, Padua. Journal of Athletic Training 2011.
- Predictors of Frontal Plane Knee Excursion During a Drop Land in Young Female Soccer Players. Sigward, Susumu, and Powers. Sports Physical Therapy, 2008.
- The effect of an inclined landing surface on biomechanical variables during a jumping task. Hagins, Pappas, Kremenic, Orishimo, Rundle. Clinical Biomechanics, 2007.