17Background: External loading of the ligamentous tissues induces mechanical creep, which 18 modifies neuromuscular response to perturbations. It is not well understood how ligamentous 19 creep affects athletic performance and contributes to modifications of knee biomechanics during 20 functional tasks. 21 Hypothesis/Purpose: The purpose of this study was to examine the mechanical and 22 neuromuscular responses to single leg drop landing perturbations before and after passive 23 loading of the knee joint. 24 Study Design: Descriptive laboratory study 25 Methods: Male (n=7) and female (n=14) participants' (21.3 ± 2.1 yrs, 1.69 ± 0.09 m, 69.3 ± 13.0 26 kg) right hip, knee, and ankle kinematics were assessed during drop landings performed from a 27 30 cm height onto a force platform before and after a 10 min creep protocol. Electromyography 28 (EMG) signals were recorded from rectus femoris (RF), vastus lateralis (VL), vastus medialis 29 (VM), semimembranosus (SM), and biceps femoris (BF) muscles. The creep protocol involved 30 fixing the knee joint at 35° during static loading with perpendicular loads of either 200 N (males) 31 or 150 N (females). Maximum, minimum, range of motion (ROM), and angular velocities were 32 assessed for the hip, knee, and ankle joints, while normalized average EMG (NAEMG), average 33 vertical ground reaction forces (aVGRF), and rate of force development (RFD) were assessed at 34 landing. Rate of force development (RFD) was calculated during the landings using ANOVAs. 35 Alpha was set at 0.05.36