Peak oxygen uptake measured during a perceptually-regulated exercise test is reliable in community-based manual wheelchair users

This study aimed to compare test-retest reliability and peak exercise responses from ramp-incremented (RAMP) and maximal perceptually-regulated (PRETmax) exercise tests during arm crank exercise in individuals reliant on manual wheelchair propulsion (MWP). Ten untrained participants (9 male) completed four trials over a 2-week period, performing two RAMP (0-40 W + 5-10 W·min-1) trials one week followed by two PRETmax trials the next, or vice versa. PRETmax consisted of five, 2-min stages performed at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20. Participants freely changed the power output to match the required RPE. Gas exchange variables, heart rate, power output, RPE and affect were determined throughout trials. The V̇ O2peak from RAMP (14.8 ± 5.5 ml·kg-1 ·min-1 ) and PRETmax (13.9 ± 5.2 ml·kg-1 ·min-1) trials were not different (P = 0.08). Measurement error was 1.7 and 2.2 ml·kg-1 ·min-1 and coefficient of variation 5.9% and 8.1% for measuring V̇ O2peak from RAMP and PRETmax, respectively. Affect was more positive at RPE 13 (P = 0.02), 15 (P = 0.01) and 17 (P = 0.01) during PRETmax. This study shows the PRETmax can be used to measure V̇ O2peak in participants reliant on MWP and leads to a more positive affective response compared to RAMP

Comparison between esophageal and intestinal temperature responses to upper-limb exercise in individuals with spinal cord injury

Objective: Individuals with spinal cord injuries (SCI) may present with impaired sympathetic control over thermoregulatory responses to environmental and exercise stressors, which can impact regional core temperature (Tcore) measurement. The purpose of this study was to investigate whether regional differences in Tcore responses exist during exercise in individuals with SCI. Setting: Rehabilitation centre in Wakayama, Japan. Methods: We recruited 12 men with motor-complete SCI (7 tetraplegia, 5 paraplegia) and 5 able-bodied controls to complete a 30-minute bout of arm-cycling exercise at 50% V̇ O2peak. Tcore was estimated using telemetric pills (intestinal temperature; Tint) and esophageal probes (Teso). Heat storage was calculated from baseline to 15 and 30 minutes of exercise. Results: At 15 minutes of exercise, elevations in Teso (Δ0.39±0.22°C; P<0.05), but not Tint (Δ0.04±0.18°C; P=0.09), were observed in able-bodied men. At 30 minutes of exercise, men with paraplegia and able-bodied men both exhibited increases in Teso (paraplegia: Δ0.56±0.30°C, P<0.05; able-bodied men: Δ0.60±0.31°C, P<0.05) and Tint (paraplegia: Δ0.38±0.33°C, P<0.05; able-bodied men: Δ0.30±0.30°C, P<0.05). Teso began rising 7.2 min earlier than Tint (pooled, P<0.01). Heat storage estimated by Teso was greater than heat storage estimated by Tint at 15 minutes (P=0.02) and 30 minutes (P=0.03) in men with paraplegia. No elevations in Teso, Tint, or heat storage were observed in men with tetraplegia. Conclusions: While not interchangeable, both Teso and Tint are sensitive to elevations in Tcore during arm-cycling exercise in men with paraplegia, although Teso may have superior sensitivity to capture temperature information earlier during exercise