Primary Outcome Measures:
- Ability Score [ Time Frame: within a 14 day period ] [ Designated as safety issue: No ]
The ability score is the sum of the number of items successfully completed in the wheelchair propulsion assessment. There are 8 items in the assessement, which will be completed in the following order: 1) Figure of 8 Shape, 2) Doorstep Crossing, 3) Platform Ascent, 4) 15 meter sprint, 5) Ramp Ascent (5% grade), 6) Ramp Ascent (8% grade), 7) 150 meter propulsion, and 8) Timed Level Transfer.
Secondary Outcome Measures:
- Muscular strength [ Time Frame: 1 day ] [ Designated as safety issue: No ]
Upper extremity dynamic strength testing will be performed on a Helms equalizer 1000 multi-station exerciser using the following maneuvers: overhead press, horizontal row, vertical butterfly, biceps curl, latissimus pull down (either to the chest or neck), and dips. The 1-repetition maximum (1-RM) will be calculated using the Mayhew regression equation.
- Anaerobic power [ Time Frame: 1 day ] [ Designated as safety issue: No ]
Participants will propel a table-mounted Monark 894e ergometer for 30 seconds at maximal speed against constant force. The constant resistance for each subject will be set at 1.5% and 3.5% of their body mass, for tetraplegia and paraplegia respectively. Data for three variables will be obtained: a) peak power, defined as the highest average mechanical power measured during any 5-second period, b) mean power, the average power sustained during the 30-second test period, and c) rate of fatigue, defined as the degree of power drop-off during the test.
- Cardiovascular endurance [ Time Frame: 1 day ] [ Designated as safety issue: No ]
Endurance will be measured using a calibrated upper arm ergometer. An initial exercise workload of 0 Watts at 60 revolutions per minute (RPM) for three minutes will be followed by three minute stages increasing in 20 Watt increments. Responses to exercise will be continuously monitored via open-circuit spirometry and 12-lead electrocardiography. Peak Work will be defined as volitional fatigue, inability to maintain targeted workload, or the point at which increasing workload fails to further increase VO2.
The ability to independently self-propel and transfer oneself is a crucial component of daily life for individuals with a spinal cord injury. This ability is related in part to an individual's strength, power, and endurance, but it is unknown which of these measures is most important to achieve a high level of wheelchair function. Identification of which physical performance parameters are best related to wheeled mobility performance is essential in developing interventions to improve said performance. Currently, clinic-friendly assessments of a person's wheeled mobility ability do not exist. We have developed a modified, clinic-friendly version of validated wheelchair mobility assessment that can be completed in most clinics. Before it can be implemented by clinicians its reliability must be established. Crossvalidating it against standard measures of physical performance will allow for the identification of the most appropriate exercise interventions to improve independent wheeled mobility.