Three replications were conducted, and the maximum exertion among the three trials was considered as the MVTE of a given condition.
Both handwheel type and similarity factors significantly affected MVTE (Table 3).
For the effect of operating plane, Figure 5 shows that the mean MVTE in the frontal plane (4.5 Nm) was significantly less than that in the transverse and sagittal planes (5.2 and 5.1 Nm, p [less than] .001).
As discussed, a power grasp can exert significantly greater MVTE than can a precision grasp under all the conditions (Rows 1, 4, 5, and 6 in Table 5).
For the consideration of the effective shear force, which is obtained by using the MVTE divided by the radius of handwheels (half the effective diameter), the average shear force was less than 175 N for men and 113 N for women under the power grasp condition (Table 7).
TABLE 6 The Mean and Relative MVTE of Different Types MVTE (Nm) Relative MVTE(b) Diameter(a) Type Male Female Ratio Male Female Smooth 5.15 3.46 1 5.15 3.46 Curved 6.35 4.17 1.122 5.66 3.72 Knurled 6.43 4.15 1.46 5.61 3.62 a Ratio among the effective diameter in Table 1; b ratio of the MVTE over diameter ratio.
The mean MVTE of women was about two-thirds that of men.