Background/Objective: Tilt and recline variable position seating systems are most commonly used for pressure relief to decrease potential for skin breakdown. This study provides quantitative information on the magnitudes of loading on the seat and back during phases of tilt, recline, and standing. The objective of this study was to show that the amount of force reduction at the seat would differ across these 3 methods within their respective clinical ranges. Participants: Six able-bodied (AB) subjects (2 men, 4 women) with a median age of 25 years, and 10 subjects (8 men, 2 women) with spinal cord injury (SCI) with a median age of 35.5 years. Methods: Subjects sat on a power wheelchair with Tekscan pressure mats placed underneath a foam backrest and cushion. Data were collected at 5 positions for each method. Order of position and method tested were randomized. Linear regressions were used to calculate the relationships of normalized seat and backrest forces to seat and backrest angles for each chair configuration. Results: Normalized seat loads had strong linear relationships with the angles of change in tilt, recline, and standing for both groups. Maximum decreases in seat load occurred at full standing and full recline in the SCI subjects and in full standing in the AB subjects. Loads linearly increased on the back during tilt and recline and linearly decreased during standing for both groups. Conclusions: Standing and recline offered similar seat load reductions at their respective terminal positions. Standing also reduced loading on the backrest. Recognizing that each method had clinical benefits and drawbacks, the results of this study indicate that tilt, recline, and standing systems should be considered as a means of weight shifting for wheelchair users.

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Background/Objective: The development of simple postural stability tests that relate to performance of activities of daily living (ADL) and can be quickly performed in a clinical setting may assist clinicians in determining appropriate wheelchair configurations and postural supports in an efficient manner. The study's purpose was to validate 3 clinical measures of reach-functional reach (FR), reach area (RA), and bilateral reach (BR)-against the performance of ADL tasks.Methods: Two groups of 20 subjects differing by time since spinal cord injury were tested. Three measures of reach-FR, RA, and BR-were recorded with and without permitting compensatory strategies. Subjects also attempted a series of ADL tasks. Group 2 subjects participated in test-retest reliability of the reach measures and to measure reach while using compensatory strategies. Correlation, ANOVA, and linear regression were used for analysis.Results: Regression analysis showed that injury level was a significant predictor of success in performing ADL tasks (%ADL). Significant but not strong correlations were found between %ADL and all uncompensated reach measures. Within Group 2 subjects, compensated FR (r ¼ 0.663) and RA (r ¼ 0.647) were more related to the %ADL score than the uncompensated FR (r ¼ 0.348) and RA (r ¼ 0.305) measurements. BR had the strongest relationship with %ADL scores (P ¼ 0.031) and was the only significant uncompensated reach measurement within the regression analyses.Discussion and Conclusion: While working with clients on seated stability and functional movement, clinicians should be encouraged to incorporate BR tasks because it has the strongest relationship to ADL performance. Researchers interested in studying postural control and stability during functional tasks should consider using uncompensated reach measures.

Differences in tilt-use illustrated the variability in function and activity among users, as well as the diverse benefits of a tilt system for different users. Further study into why subjects did not regularly achieve PRT magnitudes would be valuable to inform improved training, education and follow-up.

Background and Purpose. Manual wheelchair configurations commonly include “squeezing” the wheelchair frame to improve balance for users with spinal cord injuries. This squeezing is achieved by lowering the rear portion of the seat relative to the front of the seat while maintaining the same back angle. The study's purpose was to examine the effect of increasing posterior seat inclination on buttock interface pressures. Subjects. Nine male and 5 female subjects (mean age=37 years, SD=11.2, range=19–55) with complete thoracic or lumbar spinal cord injury were tested. Methods. Subjects sat on a pressure mat placed over a foam cushion. Pressure readings were taken at seat angles reflecting seat height decreases of 0, 5.1, 7.6, and 10.2 cm (0, 2, 3, and 4 in) of the rear of the seat relative to the front of the seat. An analysis of variance and a Duncan multiple range test were used for data analysis. Results. No meaningful differences were found in measurements of interface pressure (dispersion index, contact area, and seat pressure index), total force on seat, or peak pressure index with posterior seat inclination. Discussion and Conclusion. The data indicate no meaningful evidence that squeezing a wheelchair frame increases seat interface pressures.