Table 3. Linear regression (LR) coefficients following cross validation on the training subset.

Peak vGRF [BW]	y= 2.23 + 0.15*Speed + 0.33* Accel-based Est. −0.34*Step Freq.
	B	SE	t	p
Intercept	2.23	0.46	4.87	0.000
Speed [m/s]	0.15	0.03	4.42	0.000
Acceleration-based Estimate [BW]	0.33	0.05	6.54	0.000
Step Frequency [Hz]	−0.34	0.12	−2.84	0.006
Body Mass [kg]	0.001	0.003	0.50	0.621
Vertical Impulse [BW*s]	y= 0.69 − 0.10*Step Freq.
	B	SE	t	p
Intercept	0.69	0.02	31.13	0.000
Speed [m/s]	−0.002	0.001	−1.73	0.089
Acceleration-based Estimate [BW*s]	−0.05	0.03	−1.79	0.079
Step Frequency [Hz]	−0.10	0.004	−25.95	0.000
Body Mass [kg]	0.00003	0.00009	0.32	0.752
Contact Time [s]	y= 0.230 − 0.019*Speed + 0.151*Accel-based Est. + 0.0007*Body Mass
	B	SE	t	p
Intercept	0.230	0.033	6.88	0.000
Speed [m/s]	−0.019	0.002	−8.62	0.000
Acceleration-based Estimate [s]	0.151	0.063	2.42	0.019
Step Frequency [Hz]	−0.011	0.007	−1.51	0.135
Body Mass [kg]	0.0007	0.0002	4.05	0.000

Notes.

Unstandardized coefficients (B), coefficient standard errors (SE), t values (t), and p values (p) are listed for independent variables used to predict peak vertical ground reaction force (vGRF), vertical impulse, and contact time, where Accel-based Est. is the Acceleration-based estimate and Freq. is Frequency. Equations with statistically significant predictor variables are included. Bold p values indicate p < 0.05.