Mateusz Kukla, Michał Kończak, Maciej Berdychowski, Dominik Rybarczyk, Bartosz Wieczorek, Łukasz Warguła
Abstract
Manual wheelchair users may have reduced physical activity and total energy expenditure, while wearable devices may not adequately capture external mechanical demand during wheelchair propulsion. This pilot study examined whether wheel-level mechanical power combined with heart rate could estimate mass-specific oxygen uptake (V̇O2/kg) during manual wheelchair propulsion. Ten long-term manual wheelchair users aged 29–38 years completed 3-min trials under three progressively loaded conditions on a wheelchair ergometer.
Introduction
People with disabilities constitute a population affected by substantial health disparities [1]. Consumer-level wrist-worn activity monitors have also shown limited accuracy at lower movement frequencies during wheelchair propulsion [2]. In individuals with SCI who use wheelchairs, reduced physical activity and the associated risk of obesity create a need for reliable information on activity-related energy expenditure [3]. Dedicated physical-activity monitoring systems have therefore been developed to estimate energy expenditure in manual wheelchair users [4].
Methods
Participants
A total of 10 volunteers participated in the study, including both males and females aged between 29 and 38 years. Inclusion criteria comprised all reasons for wheelchair use, provided that participants had used a wheelchair for at least 20 hours per week for a minimum of 10 years. Exclusion criteria included the inability to use a manual wheelchair, specifically in individuals with a spinal cord injury at the level of C8 or above, as well as the presence of upper limb joint or muscle disorders. Participants were also excluded if they had any illness or injury that could interfere with their participation in the planned experimental procedures, particularly respiratory infections that could affect metabolic measurements.
Results
The experiments were conducted under three conditions, each corresponding to increasing levels of load torque ( ). In the first condition, the mean velocity was 1.8 ± 0.8 km/h, with a mass-specific oxygen uptake of 9.0 ± 1.7 mL O2·kg−1·min−1, while energy expenditure per minute was 3.4 ± 0.6 kcal/min. In the second condition, the mean velocity was 1.8 ± 0.8 km/h, with a V̇O2/kg value of 10.2 ± 1.5 mL O2·kg−1·min−1, and energy expenditure per minute was 3.9 ± 0.5 kcal/min. Finally, in the third condition, the mean velocity was 1.5 ± 0.8 km/h, while V̇O2/kg was 11.3 ± 1.5 mL O2·kg−1·min−1, and energy expenditure per minute was 4.3 ± 0.6 kcal/min. For the analyzed conditions, the mean load torque values were 1.9 ± 0.4 Nm, 2.3 ± 0.7 Nm, and 3.4 ± 1.5 Nm, respectively. A summary of the obtained results is presented in Table 2.
Discussion
A previous study reported a linear relationship between wheelchair propulsion velocity and MET-based estimates of metabolic demand [3]. Previous studies [30–32] have also demonstrated systematic changes in energy-expenditure-related outcomes with increasing wheelchair propulsion velocity, although the metabolic variables and their definitions differed between studies. Therefore, regression analysis was performed in the present study to assess the relationship between mean wheelchair velocity and directly measured V̇O2/kg. Analysis of the presented data, together with the coefficient of determination ( ), indicates the existence of a strong linear relationship between the analyzed variables.
Conclusions
Within the framework of the present pilot study, a preliminary model was developed to estimate mass-specific oxygen uptake (V̇O2/kg) during manual wheelchair propulsion based on mechanical power and heart rate. The findings suggest that these variables may provide useful complementary information for estimating metabolic demand; however, the observed relationships and predictive performance should be interpreted cautiously given the small and heterogeneous study sample. The proposed model has undergone only internal participant-level evaluation using leave-one-participant-out cross-validation and should not be regarded as externally validated.
Citation: Kukla M, Kończak M, Berdychowski M, Rybarczyk D, Wieczorek B, Warguła Ł (2026) A preliminary model for estimating mass-specific oxygen uptake during manual wheelchair propulsion from mechanical power and heart rate. PLoS One 21(10): e0359323. https://doi.org/10.1371/journal.pone.0359323
Editor: Raul Bartolomeu, Polytechnic University of Guarda, PORTUGAL
Received: June 15, 2026; Accepted: September 12, 2026; Published: October 6, 2026
Copyright: © 2026 Kukla et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: The datasets used and/or analyzed during the current study are available at: https://doi.org/10.18150/93AIYT.
Funding: This research was conducted as part of the project “Innovative Drive Systems for Wheelchairs—Design, Prototype, Research”, project no. “Rzeczy są dla ludzi/0004/2020”, funded by the National Centre for Research and Development. The presented work was co-funded with grant 0614/SBAD/1603 for education allocated by the Ministry of Science and Higher Education of the Republic of Poland. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study.
Competing interests: The authors have declared that no competing interests exist.
https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0359323#sec001
