During a forceful eccentric contraction of the quadriceps while landing a jump, why does the risk of an ACL tear increase more than with concentric contraction?

💡 Explanation

An ACL tear risk increases during eccentric contraction because the stretch-shortening cycle generates a high-impact load and greater muscle force, exceeding the ACL's tensile strength. This impairs the knee's ability to effectively dissipate force, therefore the ligament is stressed rather than protected by muscle contraction, because concentric actions distribute forces differently.

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