Table 5.

Ankle plantarflexor muscle group regression equation, model parameters, diagnostic statistics, participant characteristics (mean ± standard deviation), and between-session reliability of ultrasound measurements

Equation $\text{Ankle plantarflexors muscle volume}=878.606+\left(0.553\times \text{lateral gastrocnemius cross}-\text{sectional area at 25}\%\text{of shank length}.\text{body mass}\right)$
	β	Standard error (lower limb–upper limit)	p value
Constant	878.606	140.417 (572.662–1184.549)	<0.001
Lateral gastrocnemius cross-sectional area at 25% of shank length.body mass	0.553	0.201 (0.115–0.991)	0.018
R2	0.387
Adjusted R2	0.336
Standard error of the estimate (cm3)	134.91 (10.78%)
Mean cross-validation residual (cm3)	92.44 (6.37%)
Durbin–Watson statistic	1.44

	Model-development group	Cross-validation group (range)	Between-session difference (TEM)
Height (m)	1.81 ± 0.07	1.80 (1.72–1.88)
Body mass (kg)	78.5 ± 7.8	84.1 (67.2–106.5)
Lateral gastrocnemius cross-sectional area at 25% of shank length (cm2)	8.6 ± 1.9	10.2 (9.0–11.9)	0.24 (2.5%)
Ankle plantarflexor muscle volume (cm3)	1252.0 ± 165.5	1451.5 (1198.8–1748.2)

Model-development group n = 14, cross-validation group n = 4