Relationship between asymmetrical jump-landing impact and quadriceps strength after unilateral anterior cruciate ligament reconstruction

Primary and secondary injuries of the anterior cruciate ligament (ACL) often occur when athletes try to decelerate the body’s momentum during single-leg landing after jumping in sports such as basketball and handball [1,2]. To return to sports, 80–90% of athletes who experience primary ACL injury undergo reconstruction surgery and long-term postoperative rehabilitation [3-5]. The incidence of secondary injuries for the first 2–15 years after return to sports is 5.9–34% higher than that of primary injuries [6-9]. Moreover, athletes need a longer period of time to return to sports after revision reconstruction than after primary reconstruction [10].