Abstract

The ventilatory threshold (VT) separates low- from moderate-intensity exercise, the respiratory compensation point (RCP) moderate- from high-intensity exercise. Both concepts assume breakpoints in respiratory data. However, the objective determination of the VT and RCP using breakpoint models during upper-body modality exercise in wheelchair athletes with spinal cord injury (SCI) has received little attention. Therefore, the aim of this study was to compare the fit of breakpoint models (i.e., two linear regression lines) with continuous no-breakpoint models (i.e., exponential curve/second-order polynomial) to respiratory data obtained during a graded wheelchair exercise test to exhaustion. These fits were compared employing adjusted R2, and blocked bootstrapping was used to derive estimates of a median and 95% confidence intervals (CI). V̇O2-V̇CO2 and V̇E/V̇O2-time data were assessed for the determination of the VT, and V̇CO2-V̇E and V̇E/V̇CO2-time data for the determination of the RCP. Data of 9 wheelchair athletes with tetraplegia and 8 with paraplegia were evaluated. On an overall group-level, there was an overlap in the adjusted R2 median ± 95% CI between the breakpoint and the no-breakpoint models for determining the VT (V̇O2-V̇CO2: 0.991 ± 0.003 vs. 0.990 ± 0.003; V̇E/V̇O2-time: 0.792 ± 0.101 vs. 0.782 ± 0.104, respectively) and RCP (V̇E-V̇CO2: 0.984 ± 0.004 vs. 0.984 ± 0.004; V̇E/V̇CO2-time: 0.729 ± 0.064 vs. 0.691 ± 0.063, respectively), indicating similar model fit. We offer two lines of reasoning: (1) breakpoints in these respiratory data exist but are too subtle to result in a significant difference in adjusted R2 between the investigated breakpoint and no-breakpoint models; (2) breakpoints do not exist, as has been argued previously.

Highlights

  • In order to optimize endurance performance, athletes with an impairment often structure their training according to exercise domains, described by low, moderate, and high-intensity zones (Bhambhani et al, 1995; Coutts and McKenzie, 1995; Zeller et al, 2017)

  • Whilst there is an abundance of research focusing on the use of these methods in able-bodied athletes during lower- or whole-body exercise (Seiler and Kjerland, 2006; Seiler and Tønnessen, 2009; Pettitt et al, 2013), there is a lack of studies identifying these breakpoints to distinguish exercise domains in wheelchair athletes during upper-body exercise

  • There was no difference between the fit of breakpoint vs nobreakpoint models for either of the ventilatory threshold (GET) or respiratory compensation point (RCP) approaches derived from data collected during a graded exercise test to exhaustion

Read more

Summary

Introduction

In order to optimize endurance performance, athletes with an impairment often structure their training according to exercise domains, described by low-, moderate-, and high-intensity zones (Bhambhani et al, 1995; Coutts and McKenzie, 1995; Zeller et al, 2017). These exercise domains are distinguished using thresholds with a variety of methods that are based on either. The RCP is determined by a breakpoint in the V E/V CO2time (ventilatory equivalent method) (Reinhard et al, 1979) or V CO2-V E relationship (Beaver et al, 1986). Whilst there is an abundance of research focusing on the use of these methods in able-bodied athletes during lower- or whole-body exercise (Seiler and Kjerland, 2006; Seiler and Tønnessen, 2009; Pettitt et al, 2013), there is a lack of studies identifying these breakpoints to distinguish exercise domains in wheelchair athletes during upper-body exercise

Objectives
Methods
Discussion
Conclusion
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.