Reliability of propulsion technique and physiological parameters during wheelchair ergometer tests and its use in assessing the effects of different hand rim types

PURPOSE: Wheelchair optimisation in clinical settings often relies on expert opinion from static wheelchair seating posture. A wheelchair ergometer provides biomechanical and physiological insights during propulsion. This study assessed the reliability of propulsion technique and physiological parameters in submaximal and sprint tests and used these values to compare two hand rim types.

MATERIALS AND METHODS: Nineteen non-wheelchair users completed two exercise blocks per hand rim type (Gekko vs. conventional) on a wheelchair ergometer. Each block included a 4-min submaximal test and a 30 s sprint. The intraclass correlation coefficient (ICC), standard error of measurement (SEM) and smallest detectable change (SDC) were calculated to assess reliability for one to four exercise blocks. Hand rim differences were analysed using a mixed-effects model.

RESULTS: Submaximal propulsion technique showed good to excellent reliability (ICC = 0.75-1.00), while physiological variables and sprint propulsion technique had moderate to excellent reliability (ICC = 0.5-0.95). SDCs ranged from 12 to 29% (submaximal) and 13 to 25% (sprint), except for negative power variables (25-70%). Averaging the two, three or four tests reduced SDCs by 29%, 42% and 50%, respectively, compared to one test. The Gekko rim outperformed the conventional rim in negative power (submaximal) and in distance, velocity and power (sprints).

CONCLUSIONS: The submaximal test demonstrated better reliability and lower SDCs than the sprint test. The Gekko rim performed better at group level but not for every individual. Using SDCs instead of group results enhances clinical relevance. Future research should validate these findings in wheelchair users to support evidence-based wheelchair setup recommendations.Implications for rehabilitationThe study showed that submaximal propulsion technique has good-to-excellent reliability, while submaximal physiological parameters and sprint propulsion technique showed moderate-to-excellent reliability. Smallest detectable change (SDC) values varied, with higher values seen in negative power and physiological parameters, and generally higher SDCs in the sprint test.Although group-level statistics showed significant differences in propulsion technique (favouring the Gekko hand rim), individual analysis using SDC cut-offs revealed variations among participants. This highlights that wheelchair adaptations should be evaluated at an individual level, as group results may not capture important differences that matter for specific users.To detect the most meaningful individual differences, it is recommended to average the results of four tests. However, since the most significant reduction in SDCs occurs between one and two tests, at least two tests should be conducted when time or physical capacity is limited.The findings are not only relevant for comparing hand rims. SDC thresholds can be used to assess a wide range of individual factors, such as propulsion technique, fitness or wheelchair features (e.g., seat height). These thresholds can help tailor interventions based on the unique needs of each wheelchair user.