Cardiorespiratory fitness in individuals with spinal cord injury: the relationship with motor completeness

OBJECTIVE: To compare cardiorespiratory fitness (CRF) in individuals with motor complete versus motor incomplete spinal cord injury (SCI), while accounting for lesion level (high versus low). It was hypothesized that individuals with motor incomplete injuries would demonstrate higher CRF levels than those with motor complete injuries, regardless of lesion level.

DESIGN: Retrospective multicenter cohort study.

SETTING: Dutch rehabilitation centers (N=12) involved in training participants for the HandbikeBattle event.

PARTICIPANTS: In total, 217 individuals with SCI and a rehabilitation history who participated in the HandbikeBattle between 2013 and 2023 (excluding 2020 to 2022 due to the COVID-19 pandemic) were included. The final analysis included 202 participants.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Indicators of CRF were peak oxygen uptake (VO 2peak) and peak power output (PPO), assessed during a cardiopulmonary exercise test on an arm ergometer.

RESULTS: Multilevel regression analyses showed that motor completeness of the lesion was not associated with either relative or absolute values of VO 2peak and PPO. Lesion level was associated with both VO 2peak and PPO (relative and absolute), indicating that individuals with lower lesion levels exhibited higher CRF outcomes compared to those with higher lesion levels.

CONCLUSIONS: CRF is not determined by motor completeness of the lesion, but is affected by neurological level of injury. These findings indicate that CRF should be addressed in individuals with both motor complete and motor incomplete SCI. Exercise intensity and progression should be tailored to the individual's neurological level and functional capacity to optimize training adaptations. This knowledge may improve clinical interpretation of fitness assessments and support more personalized exercise interventions in the SCI population.