Effects of Prolonged Running-Induced Fatigue on the Periodicity of Shank-Foot Segment Coupling and Free Torque

ORIGINAL Lower Extremities' Joint Stability during the Elderly Woman's Walking

“…The input parameter "m" represents the pattern length being compared, while "r" is the allowable tolerance. Precedent studies were referenced for the detailed steps involved in the ApEn calculation (Stergiou, 2004;Ryu, 2016). Moreover, to test the assumption that the observed time series data represented the outcome of definitive dynamic types of the analyzed system (Theiler, Eubank, Longtin, Galdrikian, & Farmer, 1992), ApEn values were calculated after performing a surrogate data test (pseudo-periodic surrogate) on the time series data on 20 strides.…”

Relationship between Center of Pressure and Local Stability of the Lower Joints during Walking in the Elderly Women

“…The calculation of 3D angles in the lower extremity joints used the Cardan XYZ sequence method (Hamill & Ryu, 2004), calculating values for 20 strides in the right foot support phase. The support phase was established as the range from the moment of the right foot touching down on the treadmill when the vertical ground reaction force (GRF) is ≥5 N to the moment of lifting off when GRF is <5 N. To examine local stability of 3D angles of hip, knee, and ankle joints calculated in this manner, a nonlinear method of ApEn was used to calculate the periodicity (Ryu, 2016), with larger ApEn values being considered to show greater instability (Preatoni et al, 2014;Ryu, 2016). For CoP calculation, 6 components of GRF data (Fx, Fy, Fz, Mx, My, and Mz) obtained from the treadmill were used on the right foot support phase for 20 strides, just as in the calculation of kinematic variables.…”