Backward Double Integration is a Valid Method to Calculate Maximal and Sub-Maximal Jump Height

Figures & data

Figure 1. Example of net GRF trace of one trial with event detections for quiet standing, start of the countermovement, take-off, landing and end of landing.

Table 1. Bland-Altman analysis bias, standard deviation (SD) of bias, limits of agreement (LoA), Pearson coefficient of determination, Cohen’s d effect size and 95% confidence interval and Intraclass Correlation Coefficient (ICC) and 95% Confidence Interval of the FDI, BDI and FT+C methods compared to the Kinematic method.

Method	Bias (cm)	SD of Bias (cm)	95% LoA (cm)	R^2	Effect Size and 95% Confidence Interval	ICC and 95% Confidence Interval
Maximal Jumping
FDI	−0.4	0.9	−2.2–1.5	0.989	0.02 (−0.02–0.05)	0.994 (0.99–1.00)
BDI	−0.1	1.2	−2.3–2.2	0.983	−0.04 (–0.09 – 0.01)	0.995 (0.99–1.00)
FT+C	−0.4	2.3	−4.8–4.1	0.9386	−0.04 (–0.11 – 0.03)	0.954 (0.89–0.98)
Sub-maximal Jumping
FDI	−0.1	0.7	−1.5–1.4	0.988	−0.02 (–0.05 – 0.02)	0.995 (0.99–1.00)
BDI	−0.1	0.9	−1.7–1.9	0.982	−0.02 (0.06–0.02)	0.996 (0.99–1.00)
FT+C	0.2	2.3	−4.3–4.6	0.931	−0.01 (–0.07 – 0.09)	0.927 (0.84–0.97)

Figure 2. Raw pairwise data of BDI and FT+C compared to the FDI method. Lower graphs indicate Cohen’s d effect sizes and confidence intervals. Graph A presents maximal jumping, while graph B presents indicates sub-maximal jumping.