Biomechanical Analysis of Injury Factor According to the Change of Direction After Single-leg Landing

Sports injuries occur frequently during various sports competitions, and many studies have been conducted to improve athletic performance and prevent injuries (Mcnitt-Gray, 1989). Lower extremity joint injuries occur in approximately 77% of cases, with knee (21%) and ankle (18%) joint injuries accounting for significant portions of such injuries (Tropp, Askling & Gillquist, 1985). With respect to injury type, approximately 50% and 13% of all knee injuries involved the anterior cruciate ligament (ACL) and medial collateral ligament (MCL), respectively (Majewski, Susanneet & Klaus, 2006). Among the injury types, ACL injuries account for approximately 70% of non-contact injuries during actual physical activities (Meyer & Haut, 2008). Ankle injuries occur at a frequency of 50% for sprains, 17% for spasms, 12% for bruises, and 5% for fractures (Hang, 2013). Among athletes who incurred ankle sprains, >70% experienced additional and repetitive symptoms of dysfunction and re-injury (Anandacoomarasamy & Barnsley, 2005). Knee ligament injuries and ankle sprains occur during sports competitions and trainings (Hootman, Dick & Agel, 2007). Various reports have indicated that the causes of injuries include decreased range of motion (ROM) of the lower extremity joints and large impact force (Chae & Kang, 2009; Kim, Oh & Jeong, 2015; Yeow, Lee & Goh, 2011) and large valgus angle (Cho, Kim, Moon, Cho & Lee, 2010; Shin, Choi & Kim, 2015). Meanwhile, a study that compared between normal and perceived landing reported that the flexion angle of the knee was larger in perceived landing than in normal landing (Choi, 2015; Schmitz, Kulas, Perrin, Riemann & Shultz, 2007; Sigward, Pollard & Powers, 2012). Moreover, a study on landing that simulated actual sports motion reported that injuries may appear from the impact load in the lower extremity joints during landing from jumping (Kim & Cho, 2012). The cause of such injury was attributed to lower extremity joint injury from insufficient impact absorption during landing and inKJSB Korean Journal of Sport Biomechanics 2016; 26(4): 433-441 http://dx.doi.org/10.5103/KJSB.2016.26.4.433 http://e-kjsb.org eISSN 2093-9752 ORIGINAL