Radcliffe's analyses of quadrilateral sockets proposed that compression of the soft tissue along the proximal-medial aspect of the residual limb was important to prevent the socket translating laterally during single-limb support when large internal abduction moments were present, thereby minimizing discomfort and compensatory gait adaptations [3-4].
In the quadrilateral design, optimal loading of the proximal-medial aspect of the residual limb precompresses and stiffens the soft tissue, improving its ability to reduce lateral translation of the socket during prosthetic single-limb support .
The vertical GRF was plotted separately from heel strike to the beginning of the single-limb support and from the end of the single-limb support to the toe-off highlighted in Figure 1(d).
While we limited our loading and unloading phase analysis to the double-support regions, Figure 1(d) and Figure 2(a) show that loading and unloading was also occurring in the single-limb support phase and changing systematically across the different types of ambulators (note the progressively wider peaks in vertical GRF as functional walking status improves).
Most notably, paretic single-limb support time is increased (by 7.
observed that single-limb support time for the paretic limb, and to a lesser extent for the nonparetic limb, increased (from 45%-76% of total stance time ) as a function of increased BWS, which resulted in improved symmetry in single-limb support time [6-7].
observed that moderate increases in treadmill speed did not affect symmetry in either weight supported by or time spent on each limb during single-limb support .
In these studies, gait symmetry and single-limb support time in the paretic limb were greater during treadmill walking.
In the hemiparetic subjects, leg kinetic energy (KE) at toe-off in the nonparetic limb was exaggerated relative to side-matched limbs in nondisabled control subjects (Figure 1(a), dashed vs solid line), which resulted in reduced swing time in the nonparetic limb (Figure 1(b), dashed vs solid line) consistent with weakness or poor balance during single-limb support on the paretic limb .
Similar to changes observed with BWS, the addition of a handrail hold increased single-limb support time in the paretic limb.
Moreover, walking with a more normal gait pattern, such as with increased single-limb support time, can increase the functional demands on the paretic limb, which may also contribute to positive treatment outcome [7,18].
6-7] found that single-limb support time in the paretic limb increased with BWS, which can contribute positively to treatment outcome.