The Biomechanics of Lower Limb during Active Landing and Passive Landing

Objective:To examine the kinematics,impact force,tissue vibration and muscle activity during active landing(AL)and passive landing(PL).In addition,the aim was to understand the regulation mechanism of nerves-muscle skeletal system during landing.Methods:Twelve trained basketball male volunteers in physical education were required to complete three different attitudes(30cm、45cm、60cm)×two different landing models(AL & PL).The variables were measured including kinematic of lower extremity,impact characteristics,soft tissue acceleration signal and EMG signals.Results:At three different attitudes,AL showed significantly decrease the knee and hip joint angle(P<0.05),and significantly increase angle velocity(P<0.05)during the instantaneous moment of touchdown and cushion phase compared with PL.The peak of impact force(P<0.05),maximum loading rate(P<0.05)and impact frequency(P<0.05)were significantly reduce during AL compared with PL at three different attitudes.AL showed significantly decrease the maximum amplitude of accelerate of quadriceps femoris(except 60cm)(P<0.01)and hamstrings(P<0.01)at three different attitudes compared with PL.At three different attitudes,AL showed significantly increase the tissue damping(P<0.05)compared with PL.The parts of muscles showed significant increase the EMG amplitude(P<0.05)during AL in per-activation,post-activation and cushion phase compared with PL.Conclusion:At the case of AL,the human being can adjustment the landing strategy of muscle-skeletal system,which mean effective decrease the tissue vibrate under the impact force.Eventually,the effective motor control were resulted in decrease the risk of sports injuries.On the counter,muscle-skeletal system were bear higher impact force and tissue vibrate,and improve the risk of sports injuries.