Table 1.

Summary of muscle parameters used in seated-posture-control neuroprosthesis model.

Muscle Segment	l0 (m)	lst (m)	&agr; (°)	PCSA (cm2)	f (N/cm2)	Fmax (N)
Erector Spinae	0.127 [1]	0.325 [1]	13.0 [1]	26.00 [2]	57.6	1,497.0
Latissimus Dorsi 1 (lateral)	0.328 [3]	0.111	0.0 [3]	2.00 [3]	57.6	115.2
Latissimus Dorsi 2 (medial)	0.321 [3]	0.142	0.0 [3]	2.10 [3]	57.6	121.0
Rectus Abdominis	0.280 [1]	0.076 [1]	0.0 [1]	6.80 [4]	22.0	149.6
External Obliques	0.129* [5]	0.029	0.0	6.85 [6]	22.0	150.7
Internal Obliques	0.091* [5]	0.031	0.0	5.68 [6]	22.0	125.0
Quadratus Lumborum	0.073 [1]	0.045 [1]	7.4 [1]	6.40 [4]	57.6	368.6
Gluteus Maximus 1 (lateral)	0.156†[7]	0.144‡[7]	5.0 [7]	15.01 [7]	32.0	480.4
Gluteus Maximus 2 (central)	0.162†[7]	0.146‡[7]	0.0 [7]	21.51 [7]	32.0	688.2
Gluteus Maximus 3 (medial)	0.158†[7]	0.167‡[7]	5.0 [7]	14.43 [7]	32.0	461.8
Adductor Magnus (posterior)	0.131 [7]	0.260 [7]	5.0 [7]	17.41 [7]	32.0	557.1
Semimembranosus	0.080 [7]	0.359 [7]	15.0 [7]	16.86 [7]	32.0	539.5
Semitendinosus	0.201 [7]	0.262 [7]	5.0 [7]	5.37 [7]	32.0	171.8
Biceps Femoris (long head)	0.109 [7]	0.341 [7]	0.0 [7]	11.74 [7]	32.0	375.7
Rectus Femoris	0.084 [7]	0.346 [7]	5.0 [7]	12.73 [7]	32.0	778.0
Sartorius	0.579 [7]	0.040 [7]	0.0 [7]	1.70 [7]	32.0	103.9
Iliacus	0.100 [7]	0.090	7.0 [7]	8.50 [7]	50.0	425.0
Psoas Major	0.137 [7]	0.183	8.0 [7]	14.70 [7]	50.0	735.0

^*Weighted average of segments [4].

^†+10%.

^‡+15%.

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α = pennation angle, f = specific force, F_max = maximum isometric force (nondisabled), l₀ = optimal fiber strength, l_st = tendon slack length, PCSA = physiological cross-sectional area.