Table 1.

Parameters used in Eqs. (28)–(32) to estimate the stiffness of the tendons and muscle fibers with respect to the wrist. E is the elastic modulus, A_T is the average cross section of the tendon, PCSA is the physiological cross section area of the muscle, ${\ell }_f$ is the length of the muscle fibers, ${\ell }_T$ is the tendon length, l_m is the average moment arm of the muscle, P ₀ is the maximum isometric force, $K_{\theta }^P$ is the joint stiffness generated by the parallel element (muscle fibers), $K_{\theta }^S$ is the joint stiffness generated by the serial element (tendon), κ is the ratio between stiffness components. Muscles are extensor carpii radialis brevis (ECRB), extensor carpii radialis longus (ECRL), extensor carpii ulnaris (ECU), flexor carpii radialis (FCR), flexor carpii ulnaris (FCU).

	E	AT	PCSA	${\ell }_f$	${\ell }_T$	$\frac{{\ell }_f}{{\ell }_T}$	lm	Po	$K_{\theta }^P$	$K_{\theta }^S$
Wrist	(MPa)	(mm2)	(cm2)	(m)	(m)		(cm)	(N)	(Nm/rad)	(Nm/rad)	κ
ECRB	726.1	14.6	2.401	0.071	0.204	0.346	1.60	54.023	4.786	13.303	2.77
ECRL	438.1	14.2	1.300	0.127	0.264	0.476	1.50	29.250	1.267	5.300	4.13
ECU	721.6	15.7	2.100	0.059	0.215	0.272	0.60	47.250	0.709	1.896	2.67
FCR	595.4	17.7	2.119	0.060	0.230	0.259	1.60	47.678	5.001	11.715	2.34
FCU	448.0	27.4	3.636	0.042	0.208	0.202	1.40	81.810	9.376	11.589	1.23