KINETIC ANALYSIS OF UNILATERAL LANDINGS IN FEMALE VOLLEYBALL PLAYERS AFTER A DYNAMIC AND COMBINED DYNAMIC-STATIC WARM-UP JASON M. AVEDESIAN, 1 LAWRENCE W. JUDGE, 2 HENRY WANG, 1 AND D. CLARK DICKIN 1 1 Biomechanics Laboratory, Ball State University, Muncie, Indiana; and 2 School of Kinesiology, Ball State University, Muncie, Indiana ABSTRACT Avedesian, JM, Judge, LW, Wang, H, and Dickin, DC. Kinetic analysis of unilateral landings in female volleyball players after a dynamic and combined dynamic-static warm-up. J Strength Cond Res XX(X): 000–000, 2018—A warm-up is an impor- tant period before training or competition to prepare an ath- lete for the physical demands of subsequent activity. Previous research has extensively focused on the effects of warm-up in relation to various jumping performance attributes; however, limited research has examined the biomechanical nature of landings after common warm-up practices. Twelve female, collegiate-level volleyball players performed unilateral land- ings on the dominant and nondominant limb before and after dynamic warm-ups and combined dynamic-static (CDS) warm-ups. Kinetic variables of interest were measured at the hip and knee during the landing phase of a volleyball- simulated jump-landing maneuver. A significant 3-way interaction (warm-up 3 limb 3 time) for peak internal knee adduction moment was observed, as this kinetic parameter significantly increased (p = 0.01; d = 0.79) in the nondomi- nant limb at 1-minute post-CDS warm-up. No other warm-up differences were detected; however, significant main effects of limb were determined for dominant-limb internal hip abduc- tion moment (p , 0.01; d = 1.32), dominant-knee internal rotation moment (p , 0.01; d = 1.88), and nondominant- knee external rotation moment (p , 0.01; d = 1.86), which may be due to altered hip and trunk mechanics during the jump landings. This information provides strength and condi- tioning professionals with biomechanical information to deter- mine warm-up protocols that reduce the risk of injury in female volleyball athletes. KEY WORDS biomechanics, stretching, landing mechanics, anterior cruciate ligament INTRODUCTION V olleyball is a highly competitive and popular international sport, with the Fe ´de ´ ration Interna- tionale de Volleyball (FIVB) claiming 220 national federations (17) and over 800 million participants (10). In the United States, women’s collegiate volleyball has grown substantially during the past 30 years, totaling 17,119 participants in the 2015–2016 season (30). Because of repetitive jump landings and other maneuvers, injury risk in volleyball is comparable with other sports such as hockey or soccer, with injury incidence rates reported between 2.9 and 4.1 injuries per 1,000 athletic exposure hours (8). Most volleyball injuries are to lower extremity structures (1), with acute ankle sprains and knee internal derangement injuries (e.g., anterior cruciate ligament [ACL]) often occurring when a player is landing from a block or spike maneuver (42). A sprain/tear of the ACL is a severe injury accounting for approximately 26–60% of acute knee injuries in female volleyball athletes (1,28). Women participating in landing sports are 2–8 times more likely to injure the ACL compared with men (9). This increased injury rate in women can be attributed to intrinsic (e.g., greater Q-angle) and extrinsic (e.g., decreased skill level and body awareness) factors (9). When performing landings, women demonstrate movement biomechanics that elevate injury risk to the ACL and lower extremity, such as landing in an erect position with less hip and knee flexion (13), increased knee valgus (31), and higher ground reaction forces (GRFs) (32). Because of anatomical and skill differ- ences, female athletes display altered landing technique that heighten the risk of an ACL injury. Furthermore, female volleyball players often perform unilateral (single-leg) land- ings in training or competition (42), and these landings are associated with risky biomechanical patterns because of 1 limb absorbing the impact generated in the jump phase by Address correspondence to D. Clark Dickin, dcdickin@bsu.edu. 00(00)/1–10 Journal of Strength and Conditioning Research Ó 2018 National Strength and Conditioning Association VOLUME 00 | NUMBER 00 | MONTH 2018 | 1 Copyright ª 2018 National Strength and Conditioning Association