Exercise testing protocol using a roller system for manual wheelchair users with spinal cord injury.

OBJECTIVE: Determine the validity and reliability of an exercise testing protocol to evaluate cardiorespiratory measures in manual wheelchair users (MWUs) with spinal cord injury (SCI) using a roller-based (RS) wheelchair system. DESIGN: Repeated measures within-subject design. SETTING: Community-based research laboratory. PARTICIPANTS: Ten adults with SCI requiring the use of a manual wheelchair. INTERVENTIONS: Not applicable. OUTCOME MEASURES: Cardiorespiratory measures (peak oxygen consumption [VO2peak], respiratory exchange ratio [RER], pulmonary ventilation [VE], energy expenditure [EE], heart rate [HR], accumulated kilocalories [AcKcal]) and perceived exertion (RPE) were measured during three separate maximal exercise tests using an arm crank ergometer (ACE) and an RS. RESULTS: At maximal exertion, there were no significant differences in variables between groups, with moderate-to-strong correlations (P < 0.05, r = 0.79-0.90) for VO2, HR, RPE, AcKcal, and rate of EE between RS and ACE trials. Significant moderate-to-strong correlations existed between RS trials for VO2, AcKcal, rate of EE, and peak power output (P < 0.01, r = 0.77-0.97). CONCLUSIONS: VO2peak was highly correlated between ACE and RS trials and between the two RS trials, indicating the RS protocol to be reliable and valid for MWUs with SCI. Differences in perceived exertion and efficiency at submaximal workloads and maximal pulmonary ventilation at peak workloads indicated potential advantages to using the RS.

A Method for Quantifying Upper Limb Performance in Daily Life Using Accelerometers.

A key reason for referral to rehabilitation services after stroke and other neurological conditions is to improve one's ability to function in daily life. It has become important to measure a person's activities in daily life, and not just measure their capacity for activity in the structured environment of a clinic or laboratory. A wearable sensor that is now enabling measurement of daily movement is the accelerometer. Accelerometers are commercially-available devices resembling large wrist watches that can be worn throughout the day. Data from accelerometers can quantify how the limbs are engaged to perform activities in peoples' homes and communities. This report describes a methodology to collect accelerometry data and turn it into clinically-relevant information. First, data are collected by having the participant wear two accelerometers (one on each wrist) for 24 h or longer. The accelerometry data are then downloaded and processed to produce four different variables that describe key aspects of upper limb activity in daily life: hours of use, use ratio, magnitude ratio, and the bilateral magnitude. Density plots can be constructed that visually represent the data from the 24 h wearing period. The variables and their resultant density plots are highly consistent in neurologically-intact, community-dwelling adults. This striking consistency makes them a useful tool for determining if upper limb daily performance is different from normal. This methodology is appropriate for research studies investigating upper limb dysfunction and interventions designed to improve upper limb performance in daily life in people with stroke and other patient populations. Because of its relative simplicity, it may not be long before it is also incorporated in clinical neurorehabilitation practice.

Does Task-Specific Training Improve Upper Limb Performance in Daily Life Poststroke?

BACKGROUND: A common assumption is that changes in upper limb (UL) capacity, or what an individual is capable of doing, translates to improved UL performance in daily life, or what an individual actually does. This assumption should be explicitly tested for individuals with UL paresis poststroke. OBJECTIVE: To examine changes in UL performance after an intensive, individualized, progressive, task-specific UL intervention for individuals at least 6 months poststroke. METHODS: Secondary analysis on 78 individuals with UL paresis who participated in a phase II, single-blind, randomized parallel dose-response trial. Participants were enrolled in a task-specific intervention for 8 weeks. Participants were randomized into 1 of 4 treatment groups with each group completing different amounts of UL movement practice. UL performance was assessed with bilateral, wrist-worn accelerometers once a week for 24 hours throughout the duration of the study. The 6 accelerometer variables were tested for change and the influence of potential modifiers using hierarchical linear modeling. RESULTS: No changes in UL performance were found on any of the 6 accelerometer variables used to quantify UL performance. Neither changes in UL capacity nor the overall amount of movement practice influenced changes in UL performance. Stroke chronicity, baseline UL capacity, concordance, and ADL status significantly increased the baseline starting points but did not influence the rate of change (slopes) for participants. CONCLUSIONS: Improved motor capacity resulting from an intensive outpatient UL intervention does not appear to translate to increased UL performance outside the clinic.

A motor learning approach to training wheelchair propulsion biomechanics for new manual wheelchair users: A pilot study.

CONTEXT/OBJECTIVE: Developing an evidence-based approach to teaching wheelchair skills and proper propulsion for everyday wheelchair users with a spinal cord injury (SCI) is important to their rehabilitation. The purpose of this project was to pilot test manual wheelchair training based on motor learning and repetition-based approaches for new manual wheelchair users with an SCI. DESIGN: A repeated measures within-subject design was used with participants acting as their own controls. METHODS: Six persons with an SCI requiring the use of a manual wheelchair participated in wheelchair training. The training included nine 90-minute sessions. The primary focus was on wheelchair propulsion biomechanics with a secondary focus on wheelchair skills. OUTCOME MEASURES: During Pretest 1, Pretest 2, and Posttest, wheelchair propulsion biomechanics were measured using the Wheelchair Propulsion Test and a Video Motion Capture system. During Pretest 2 and Posttest, propulsion forces using the WheelMill System and wheelchair skills using the Wheelchair Skills Test were measured. RESULTS: Significant changes in area of the push loop, hand-to-axle relationship, and slope of push forces were found. Changes in propulsion patterns were identified post-training. No significant differences were found in peak and average push forces and wheelchair skills pre- and post-training. CONCLUSIONS: This project identified trends in change related to a repetition-based motor learning approach for propelling a manual wheelchair. The changes found were related to the propulsion patterns used by participants. Despite some challenges associated with implementing interventions for new manual wheelchair users, such as recruitment, the results of this study show that repetition-based training can improve biomechanics and propulsion patterns for new manual wheelchair users.

Quantifying Real-World Upper-Limb Activity in Nondisabled Adults and Adults With Chronic Stroke.

BACKGROUND: Motor capability is commonly assessed inside the clinic, but motor performance in real-world settings (ie, outside of the clinic) is seldom assessed because measurement tools are lacking. OBJECTIVE: To quantify real-world bilateral upper-limb (UL) activity in nondisabled adults and adults with stroke using a recently developed accelerometry-based methodology. METHODS: Nondisabled adults (n = 74) and adults with chronic stroke (n = 48) wore accelerometers on both wrists for 25 to 26 hours. Motor capability was assessed using the Action Research Arm Test (ARAT). Accelerometry-derived variables were calculated to quantify intensity of bilateral UL activity (ie, bilateral magnitude) and the contribution of both ULs to activity (magnitude ratio) for each second of activity. Density plots were used to examine each second of bilateral UL activity throughout the day. RESULTS: Nondisabled adults demonstrated equivalent use of dominant and nondominant ULs, indicated by symmetrical density plots and a median magnitude ratio of -0.1 (interquartile range [IQR] = 0.3), where a value of 0 indicates equal activity between ULs. Bilateral UL activity intensity was lower (P < .001) and more lateralized in adults with stroke, as indicated by asymmetrical density plots and a lower median magnitude ratio (-2.2; IQR = 6.2, P < .001). Density plots were similar between many stroke participants who had different ARAT scores, indicating that real-world bilateral UL activity was similar despite different motor capabilities. CONCLUSIONS: Quantification and visualization of real-world bilateral UL activity can be accomplished using this novel accelerometry-based methodology and complements results obtained from clinical tests of function when assessing recovery of UL activity following neurological injury.

An accelerometry-based methodology for assessment of real-world bilateral upper extremity activity.

BACKGROUND: The use of both upper extremities (UE) is necessary for the completion of many everyday tasks. Few clinical assessments measure the abilities of the UEs to work together; rather, they assess unilateral function and compare it between affected and unaffected UEs. Furthermore, clinical assessments are unable to measure function that occurs in the real-world, outside the clinic. This study examines the validity of an innovative approach to assess real-world bilateral UE activity using accelerometry. METHODS: Seventy-four neurologically intact adults completed ten tasks (donning/doffing shoes, grooming, stacking boxes, cutting playdough, folding towels, writing, unilateral sorting, bilateral sorting, unilateral typing, and bilateral typing) while wearing accelerometers on both wrists. Two variables, the Bilateral Magnitude and Magnitude Ratio, were derived from accelerometry data to distinguish between high- and low-intensity tasks, and between bilateral and unilateral tasks. Estimated energy expenditure and time spent in simultaneous UE activity for each task were also calculated. RESULTS: The Bilateral Magnitude distinguished between high- and low-intensity tasks, and the Magnitude Ratio distinguished between unilateral and bilateral UE tasks. The Bilateral Magnitude was strongly correlated with estimated energy expenditure (ρ = 0.74, p<0.02), and the Magnitude Ratio was strongly correlated with time spent in simultaneous UE activity (ρ = 0.93, p<0.01) across tasks. CONCLUSIONS: These results demonstrate face validity and construct validity of this methodology to quantify bilateral UE activity during the performance of everyday tasks performed in a laboratory setting, and can now be used to assess bilateral UE activity in real-world environments.

Validity and reliability of a system to measure passive tissue characteristics of the lumbar region during trunk lateral bending in people with and people without low back pain.

The current study examined the validity and reliability of a new system that was developed to measure lumbar region passive stiffness and end range of motion during a trunk lateral bending movement in vivo. Variables measured included force, end range lumbar region motion, torque, lumbar region stiffness, and passive elastic energy. Validity of the force measurements was examined using standard weights. Validity of lumbar region angle measurements was examined using an instrumented trunk with an electrogoniometer. Reliability of the measurements between trials within a session was examined in a sample of 50 people (25 men, 25 women; mean +/- standard deviation age = 30.7 +/- 8.9 yr); 31 people reported a history of chronic or recurrent low back pain (LBP) and 19 reported no prior history of LBP. The end range lumbar region motion and force measurements demonstrated an excellent linear relationship with the criterion standard measures. Average error between the criterion standard and observed measurements was minimal for all measurements. For reliability testing, the majority of intraclass correlation coefficient values were >0.75. The validity and reliability of the current system are sufficient to examine lumbar region stiffness and end range of motion in people with and people without LBP.

Effect of metatarsal phalangeal joint extension on plantar soft tissue stiffness and thickness.

BACKGROUND: Plantar soft tissue stiffness and thickness are important biomechanical variables to understand stress concentrations that may contribute to tissue injury. OBJECTIVE: The purpose of this study was to determine the effects of passive metatarsal phalangeal joint (MPJ) extension on plantar soft tissue stiffness and thickness. METHODS: Seventeen healthy participants (7 male, 10 female, mean age 25.3 years, S.D. 4.4 years, mean BMI 24.7 kg/m(2), S.D. 3.2 kg/m(2)) were tested. Plantar soft tissue stiffness and thickness were measured at the metatarsal heads, midfoot and heel using a custom-built indentor device and an ultrasound machine. RESULTS: Indicators of soft tissue stiffness (K1 values) at the metatarsal heads and midfoot showed increases in stiffness of 81-88% (S.D.20-33%) in the MPJ extension position compared with the MPJ neutral position. Soft tissue thickness measures at the metatarsal heads with the MPJ in neutral ranged from a mean of 8.9 to 13.5mm and decreased, on average, by 8.8% (S.D. 2.9%) with MPJ extension. CONCLUSIONS: MPJ extension has a profound effect on increasing forefoot plantar soft tissue stiffness and a consistent but minimal effect on reducing soft tissue thickness. These changes may help transform the foot into a rigid lever at push-off consistent with the theory of the windlass mechanism.

Foot pressures during level walking are strongly associated with pressures during other ambulatory activities in subjects with diabetic neuropathy.

OBJECTIVE: To assess the relationship between foot pressures measured during level walking and other types of ambulatory activity in subjects with diabetes mellitus (DM) and peripheral neuropathy (PN). DESIGN: Descriptive survey with repeated measures. SETTING: University medical center. PARTICIPANTS: Convenience sample of 16 ambulatory subjects with DM and PN. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak pressure and pressure-time integral (PTI) at the heel, great toe, first metatarsal head (MT1), and third metatarsal head (MT3) during level walking, ramp climbing, stair climbing, and turning at a self-selected speed. RESULTS: Peak pressure and PTI during level walking correlated highly with pressures during ramp climbing (r range,.85-.97) and turning (r range,.75-.96) at all regions examined and with pressures during stair climbing at MT1 and MT3 (r range,.84-.91). Correlations between pressures during level walking and stair climbing were moderate at the great toe (r range,.46-.57) and poor at the heel (r range, -.12 to -.06). With few exceptions, pressures during ramp climbing, stair climbing, and turning were less than (P<.008) or equal to pressures during level walking. We found no activity-related differences in peak pressure or PTI independent of the effects of preferred walking speed. CONCLUSIONS: Results support the clinical evaluation of peak pressure during level walking as an efficient method to screen for maximum levels of stress on the foot as patients with DM and PN perform their daily activities.

Plantar tissue stiffness in patients with diabetes mellitus and peripheral neuropathy.

OBJECTIVE: To determine if a difference exists in the plantar soft tissue of patients with diabetes mellitus (DM) and peripheral neuropathy (PN) compared with age-matched controls. DESIGN: Case-control study with a parallel 3-element 1-dimensional viscoelastic model developed to characterize indentation data. SETTING: Data collection performed in an academic physical therapy laboratory. PARTICIPANTS: Forty subjects were recruited into 2 groups (20 subjects with DM, PN, and history of plantar ulcers; 20 control subjects), matched for age (DM: 55.22+/-9.39 y; control: 55.91+/-10.97 y), gender (DM: 14 men, 6 women; control: 14 men, 6 women), and body mass index (DM: 32.96+/-8.39 kg/m(2); control: 32.58+/-7.69 kg/m(2)). INTERVENTIONS: The plantar soft tissue stiffness was measured over the first, third, and fifth metatarsals, and heel of each subject using an indentor system that accurately measures force/displacement (F/D) data. A parallel 3-element viscoelastic mechanical model was then used to transform the F/D data into values that were used to make stiffness assessments. MAIN OUTCOME MEASURE: The element coefficients of our model indicated the stiffness of the plantar tissue. RESULTS: The plantar tissue of the subjects with DM over the metatarsal heads was stiffer than the control population as indicated by one of the spring constants in the parallel 3-element model (first: 1.13+/-0.55 N/mm vs.72+/-.32 N/mm; third:.96+/-.32 N/mm vs.79+/-.17 N/mm; fifth:.90+/-.31 N/mm vs.69+/-.28 N/mm; P<.05). CONCLUSIONS: The plantar tissue of subjects with DM, PN, and a history of ulcers was stiffer than control subjects. However, additional research is needed to determine the relationship among increased soft tissue stiffness, plantar pressures, and skin breakdown.