Lower Limb Joint Angle Coordination Assessment at Sagittal Plane on Human Vertical Countermovement

Abstract

This study presents innovative analysis at the time, frequency and phase domain for lower limb joint angular coordination assessment at sagittal plane on human vertical countermovement (CM), comparing long CM on countermovement jump (CMJ) and short CM on drop jump (DJ) from 40 cm step with squat jump (SJ) in the absence of CM. Lower limb CM and muscle stretch-shortening cycle has been pointed as playing a key role on human gait efficiency as well as on run and jump performance with an open issue on objective and quantitative measures for lower limb joint angle coordination assessment at different CM in comparison with no CM condition. Case study is considered from subject specific with 20 years old, 84 kg of body mass and 1.84 m height, selected according to best performance criteria of maximum vertical jump height during CMJ, DJ and SJ from a small sample of n = 6 sports and physical education degree students with (21.5 ± 1.4) years old, (76.7 ± 9.3) kg mass and (1.79 ± 0.06) m height, with no previous injuries, specific sport abilities or training. Calibrated image system with two digital video cameras JVC GR-VL9800 operating at 100 Hz and direct linear transformation (DLT-11) was used along with Simi Motion System and Dempster adapted model with 14 segments to track 3D coordinates of joint marks and obtain joint angles, angular velocities and accelerations at sagittal plane by inverse kinematics. Entire signal analysis was implemented on complementary time, frequency and phase domains for lower limb joint angle coordination assessment at sagittal plane on human vertical jump for comparison of long, short and without CM condition. Comprehensive signal analysis allowed detection of distinct coordination at CMJ from DJ and SJ as well from untrained tested subjects to those reported on trained subjects namely with lower coordination at untrained subjects associated to inaptitude to potentiate short CM and thus presenting lower DJ performance than trained subjects.