Jump Landing and ACL Injury

Sep 04, 2017

Ligaments are made of tough fibrous material. They function to limit joint mobility to control excessive motion. The knee joint has an anterior cruciate ligament (ACL) that helps stabilise the knee. It runs diagonally in the middle of the knee. There are 4 major ligaments of the knee. When it comes to knee ligament injuries, the most often affected is the ACL.

For some athletes, knee pain after a jump is not new at all. Most likely, it is a result of a ligament injury. A recent study showed evidence of increased hip flexion during landing and increasing tensile stiffness of the quads may help reduce ACL injury.

ACL Injury

ACL rupture is a common injury in sports. It is usually associated with jump landing movements and side-step cutting activities such as basketball, soccer or tennis. Most ACL ruptures occur in non-contact situations, which appear to be likely a result of poor muscular control and improper movements rather than direct trauma.

Generally, there are higher incidences of non-contact ACL injury in females compared to males. This is because females tend to have less capability in stabilising the joint during high-impact movements.

From a biomechanical standpoint, the strains and loading in the ACL during dynamic movement are associated with forces and movements applied to the knee joint, the instantaneous position and orientation of the lower limbs, and the structure of the bone and soft tissue.

ACL injuries usually occur in high-impact sports that involve different muscle activation patterns rather than during low-impact movements of passive knee motion. In a recent study by K. Oberhofer et al, the muscle-tendon forces are thought to play an important role in the stabilisation of the knee joint, which can affect ACL loading.

The Study

The researchers studied the influence of muscle-tendon forces on ACL loading during jump-landing movements through biomechanical analyses of the healthy knee. They conducted a systematic review and gathered 26 studies in vitro and in situ.

Four in vitro studies showed a reduction of peak ACL strain when the quadriceps force was increased. One in vitro study showed a reduction of ACL loading when hamstring force was increased

The muscles are the main active joint stabilisers that help prevent knee ligaments from getting injured. The researchers found that both peak ACL strain and peak ACL force during jump landing is reduced if there is an increase in the passive resistance to stretch of the quadriceps or the hamstrings.

The results of the study suggest that increasing hip flexion during landing may help reduce ACL strain by lengthening the hamstrings. Lengthening the hamstring increases its passive resistance to stretch.

Also, increasing the tensile stiffness of the quads may help in stabilising the joint during landing. This protects the passive soft tissue structures from overloading.

Although common in sports, ACL injuries can still be minimised with the help of a physiotherapist. A physiotherapist can help you with the right kind of exercises to condition your muscles, which can ultimately help you reduce your susceptibility to injury.

If you’re in a preparation for an upcoming sport, make sure to see a Perth physiotherapist. Book an appointment at Happy Physio today on 92727359.



Oberhofer K, Hosseini Nasab SH, Schütz P, et al. The influence of muscle-tendon forces on ACL loading during jump landing: a systematic review. Muscles, Ligaments and Tendons Journal. 2017;7(1):125-135. doi:10.11138/mltj/2017.7.1.125.