Table 2.

Default moment-arm matrix for posture 1 (in mm)

	DELT1	DELT2	DELT3	PECM2	BIClong	BICshort	TRIlong	TRIlat	BRA	BRD	PT	FCR	FCU	ECRB/ECRL	ECU
SFE	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
SAA	−15.5*	34.1*	17.9*	−56.5*	5.33†	−30.7*	−6.93	0	0	0	0	0	0	0	0
SIER	5.08*	1.88*	−8.58*	9.61†	5.84	4.19*	−4.88	0	0	0	0	0	0	0	0
EFE	0	0	0	0	45.8†	45.8†	−19.6†	−19.6†	22.7†	78.6†	14.5†	13.0†	13.6†	13.1†	−2.66†
FPS	0	0	0	0	−12.8†	−12.8†	0	0	0	5.09†	9.95†	1.97†	1.17†	−0.22‡	−0.69†
WFE	0	0	0	0	0	0	0	0	0	0	0	14.9*	14.9*	−11.5*	−6.30†
WRUD	0	0	0	0	0	0	0	0	0	0	0	−7.47*	21.8*	−17.3*	25.1*

Note: Each element represents the moment arm of a given muscle (column) in a given DOF (row). Shaded values indicate the largest moment arm of a given muscle; only these values were retained for simulations without moment arm coupling. Using an arm model representing a 10th or 90th percentile male (by height) instead of the default model (50th percentile male) changed moment arms by different amounts; changes of 1–5%, 8–11%, and 23–36% are indicated by *, †, and ‡, respectively. Muscle abbreviations are given in Table 1. DOF abbreviations are defined as follows (positive direction listed first): SFE, SAA, and SIER represent SFE, adduction–abduction, and internal–external rotation, respectively; EFE and FPS represent EFE and forearm pronation–supination, respectively; and WFE and WRUD represent wrist flexion–extension and ulnar-radial deviation, respectively. Negative moment-arm values indicate resultant torques in the negative direction for that DOF. An explanation of the top row of zeros is given in the Appendix and discussed in the Limitations section of the Discussion.