Abstract-The objective of this study was to conduct a kinetic analysis of manual wheelchair propulsion during start-up on select indoor and outdoor surfaces. Eleven manual wheelchairs were fitted with a SMART Wheel and their users were asked to push on a course consisting of high-and low-pile carpet, indoor tile, interlocking concrete pavers, smooth level concrete, grass, hardwood flooring, and a sidewalk with a 5-degree grade. Peak resultant force, wheel torque, mechanical effective force, and maximum resultant force rate of rise were analyzed during startup for each surface and normalized relative to their steady-state values on the smooth level concrete. Additional variables included peak velocity, distance traveled, and number of strokes in the first 5 s of the trial. We compared biomechanical data between surfaces using repeated-measures mixed models and paired comparisons with a Bonferroni adjustment. Applied resultant force (p = 0.0154), wheel torque (p < 0.0001), and mechanical effective force (p = 0.0047) were significantly different between surfaces. The kinetic values for grass, interlocking pavers, and ramp ascent were typically higher compared with tile, wood, smooth level concrete, and high-and low-pile carpet. Users were found to travel shorter distances up the ramp and across grass (p < 0.0025) and had a higher stroke count on the ramp (p = 0.0124). While peak velocity was not statistically different, average velocity was slower for the ramp and grass, which indicates greater wheelchair/user deceleration between strokes. The differences noted between surfaces highlight the importance of evaluating wheelchair propulsion ability over a range of surfaces.Key words: access, biomechanics, community access, driving surfaces, manual wheelchair, propulsion forces, ramps, rolling resistance, sidewalks, standards, surface resistances, wheelchair propulsion.Abbreviations: ANOVA = analysis of variance, MEF = mechanical effective force, NVWG = National Veterans Wheelchair Games, SCI = spinal cord injury, 3-D = three dimensional, VA = Department of Veterans Affairs.

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Rationale and Objectives-Ultrasound is a proven method for examining soft tissue structures including tendons, and recently quantitative ultrasound has become more prevalent in research settings. However, limited reliability data has been published for these new quantitative ultrasound measures. The main study objective is to quantify the reliability and measurement error of multiple quantitative ultrasound imaging protocols for the biceps and supraspinatus tendons.Materials and Methods-Two examiners captured ultrasound images of the non-dominant long head of the biceps tendon and supraspinatus tendon from 15 able-bodied participants and five manual wheelchair users. Each examiner captured two images per subject under two different preparations which includes subject positioning and reference marker placement. Image processing (reading) was performed twice to compute nine quantitative ultrasound measures of greyscale tendon appearance using first-order statistics and texture analysis. Generalizability theory was applied to compute interand intra-rater reliability using the coefficient of dependability (Φ) for multiple study design protocols.Results-Inter-rater reliability was generally low (0.26 <Φ< 0.82), and we recommend that a single evaluator capture all images for quantitative ultrasound protocols. Most (n = 14 of 18) of the quantitative ultrasound measures exhibited at least moderate (Φ>0.50) intra-rater reliability for a single image, captured under one preparation, and read once.Conclusion-By following a protocol designed to minimize measurement error, one can increase the reliability of quantitative ultrasound measures. We believe that an appropriately designed protocol will allow quantitative ultrasound to be used as an outcome measure to identify structural changes within the tendon.

In this study we investigated the reliability of ultrasound in measuring median nerve characteristics including cross-sectional area (CSA), flattening ratio (FR), swelling ratio (SR), and mean grayscale. Generalizability theory was used to assess inter- and intrarater reliability using the dependability coefficient (phi), normalized standard error of measurement, and normalized minimum detectable change (MDC(NORM)) for multiple study design protocols. Interrater reliability was generally moderate. Intrarater reliability was mostly good (phi > 0.876) when using a single image, captured on one occasion, and being read once. Intrarater MDC(NORM) ranged from 3.8% to 6.2% for all CSA measures and SR. Using multiple images and/or readings at multiple occasions did not appreciably improve reliability measures. Ultrasound is a reliable tool for measuring median nerve characteristics. We recommend that a single evaluator capture all images for protocols aimed at quantifying median nerve ultrasound measures. We believe an appropriately designed protocol can utilize ultrasound to accurately assess changes in median nerve characteristics after activity.

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