Post-processing Peak Oxygen Uptake Data Obtained During Cardiopulmonary Exercise Testing in Individuals With Spinal Cord Injury: A Scoping Review and Analysis of Different Post-processing Strategies.

OBJECTIVES: To review the evidence regarding the most common practices adopted with cardiopulmonary exercise testing (CPET) in individuals with spinal cord injury (SCI), with the following specific aims to (1) determine the most common averaging strategies of peak oxygen uptake (V̇o2peak), (2) review the endpoint criteria adopted to determine a valid V̇o2peak, and (3) investigate the effect of averaging strategies on V̇o2peak values in a convenience sample of individuals with SCI (between the fourth cervical and sixth thoracic spinal segments). DATA SOURCES: Searches for this scoping review were conducted in MEDLINE (PubMed), EMBASE, and Web Science. STUDY SELECTION: Studies were included if (1) were original research on humans published in English, (2) recruited adults with traumatic and non-traumatic SCI, and (3) V̇o2peak reported and measured directly during CPET to volitional exhaustion. Full-text review identified studies published before April 2021 for inclusion. DATA EXTRACTION: Extracted data included authors name, journal name, publication year, participant characteristics, and comprehensive information relevant to CPET. DATA SYNTHESIS: We extracted data from a total of 197 studies involving 4860 participants. We found that more than 50% of studies adopted a 30-s averaging strategy. A wide range of endpoint criteria were used to confirm the attainment of maximal effort. In the convenience sample of individuals with SCI (n=30), the mean V̇o2peak decreased as epoch (ie, time) lengths increased. Reported V̇o2peak values differed significantly (P<.001) between averaging strategies, with epoch length explaining 56% of the variability. CONCLUSIONS: The adoption of accepted and standardized methods for processing and analyzing CPET data are needed to ensure high-quality, reproducible research, and inform population-specific normative values for individuals with SCI.

Exercise Improves Cardiorespiratory Fitness, but Not Arterial Health, after Spinal Cord Injury: The CHOICES Trial.

Arterial stiffness, as measured by carotid-femoral pulse wave velocity (cfPWV), is elevated after spinal cord injury (SCI). In the uninjured population, exercise training has been shown to reduce arterial stiffness. In a randomized, multi-center clinical trial, we evaluated the impact of two exercise interventions on cardiovascular disease risk factors in persons with chronic SCI. A total of 46 adults with motor-complete SCI with neurological levels of injury between the fourth cervical and sixth thoracic spinal cord segments (C4-T6) were randomly assigned to either body-weight-supported treadmill training (BWSTT) or arm-cycle ergometer training (ACET). Participants trained 3 days per week for 24 weeks. Exercise session duration progressed gradually to reach 30 and 60 min for ACET and BWSTT, respectively. The primary outcome was arterial stiffness, assessed by cfPWV, and was measured at baseline, 12 weeks of training, and at 24 weeks. Secondary outcomes included cardiorespiratory fitness (CRF) and cardiometabolic health measures and were measured before and after completion of training. Fourteen participants per intervention arm completed the exercise intervention. Our results show no effect of either exercise intervention on arterial stiffness (p = 0.07) and cardiometabolic health measures (p > 0.36). However, peak oxygen uptake increased with ACET compared with BWSTT (p = 0.04). The findings of this trial demonstrate that although 24 weeks of upper-body exercise improved CRF in persons with motor-complete SCI ≥T6, neither intervention resulted in improvements in arterial stiffness or cardiometabolic health measures. ClinicalTrials.gov identifier: NCT01718977.

Associations between left ventricular structure and function with cardiorespiratory fitness and body composition in individuals with cervical and upper thoracic spinal cord injury.

STUDY DESIGN: Cross-sectional. OBJECTIVE: It is known that left ventricular mass (LVM) and cardiorespiratory fitness (CRF) are associated to fat-free mass (FFM).  It is unknown if these factors associated with left ventricular (LV) structure and function outcomes in individuals with spinal cord injury (SCI). SETTING: University-based laboratory.Vancouver, BC, Canada. METHODS: Thirty-two individuals (aged 40 ± 11 years) with chronic, motor-complete SCI between the fourth cervical and sixth thoracic levels were recruited. Echocardiographic LV parameters and body composition were assessed at rest, as per the recommended guidelines for each technique. CRF was assessed during an incremental arm-cycle exercise test until volitional fatigue. The appropriate bivariate correlation coefficients [i.e., Pearson's (r) and Spearman's rank (Rs)] tests were used for normal and non-normal distributed variables, respectively. RESULTS: LV structure and function parameters were not associated with the indexed peak oxygen consumption (V̇O2peak) [i.e., relative to body weight or FFM] (Rs values ranged from -0.168 to 0.134, all P values > 0.223). The association between peak oxygen pulse and the resting echocardiographic-obtained SV was medium sized (Rs = 0.331, P = 0.069). The LVM associations with FFM and fat mass (FM) were large and small (r = 0.614, P < 0.001 and r = 0.266, P = 0.141, respectively). Associations of absolute V̇O2peak were medium- positive with FFM (Rs = 0.414, P = 0.021) but negative with FM (Rs = -0.332, P = 0.068). CONCLUSION: LV parameters measured at rest are not associated with V̇O2peak in individuals with cervical and upper-thoracic SCI. Given the observed associations between LVM and V̇O2peak with FFM, future studies may consider utilizing FFM for indexing cardiovascular measures following SCI.

Construct validation of the leisure time physical activity questionnaire for people with SCI (LTPAQ-SCI).

STUDY DESIGN: Cross-sectional construct validation study. OBJECTIVES: To test the construct validity of the Leisure Time Physical Activity Questionnaire for People with Spinal Cord Injury (LTPAQ-SCI) by examining associations between the scale responses and cardiorespiratory fitness (CRF) in a sample of adults living with spinal cord injury (SCI). SETTING: Three university-based laboratories in Canada. METHODS: Participants were 39 adults (74% male; M age: 42 ± 11 years) with SCI who completed the LTPAQ-SCI and a graded exercise test to volitional exhaustion using an arm-crank ergometer. One-tailed Pearson's correlation coefficients were computed to examine the association between the LTPAQ-SCI measures of mild-, moderate-, heavy-intensity and total minutes per week of LTPA and CRF (peak volume of oxygen consumption [V̇O2peak] and peak power output [POpeak]). RESULTS: Minutes per week of mild-, moderate- and heavy-intensity LTPA and total LTPA were all positively correlated with V̇O2peak. The correlation between minutes per week of mild intensity LTPA and V̇O2peak was small-medium (r = 0.231, p = 0.079) while all other correlations were medium-large (rs ranged from 0.276 to 0.443, ps < 0.05). Correlations between the LTPAQ-SCI variables and POpeak were also positive but small (rs ranged from 0.087 to 0.193, ps > 0.05), except for a medium-sized correlation between heavy-intensity LTPA and POpeak (r = 0.294, p = 0.035). CONCLUSIONS: People with SCI who report higher levels of LTPA on the LTPAQ-SCI also demonstrate greater levels of CRF, with stronger associations between moderate- and heavy-intensity LTPA and CRF than between mild-intensity LTPA and CRF. These results provide further support for the construct validity of the LTPAQ-SCI as a measure of LTPA among people with SCI.

Effects of exercise interventions on cardiovascular health in individuals with chronic, motor complete spinal cord injury: protocol for a randomised controlled trial [Cardiovascular Health/Outcomes: Improvements Created by Exercise and education in SCI (CHOICES) Study].

INTRODUCTION: Recent studies demonstrate that cardiovascular diseases and associated complications are the leading cause of morbidity and mortality in individuals with spinal cord injury (SCI). Abnormal arterial stiffness, defined by a carotid-to-femoral pulse wave velocity (cfPWV) ≥10 m/s, is a recognised risk factor for heart disease in individuals with SCI. There is a paucity of studies assessing the efficacy of conventional training modalities on arterial stiffness and other cardiovascular outcomes in this population. Therefore, this study aims to compare the efficacy of arm cycle ergometry training (ACET) and body weight-supported treadmill training (BWSTT) on reducing arterial stiffness in individuals with chronic motor complete, high-level (above the sixth thoracic segment) SCI. METHODS AND ANALYSIS: This is a multicentre, randomised, controlled, clinical trial. Eligible participants will be randomly assigned (1:1) into either ACET or BWSTT groups. Sixty participants with chronic (>1 year) SCI will be recruited from three sites in Canada (Vancouver, Toronto and Hamilton). Participants in each group will exercise three times per week up to 30 min and 60 min for ACET and BWSTT, respectively, over the period of 6 months. The primary outcome measure will be change in arterial stiffness (cfPWV) from baseline. Secondary outcome measures will include comprehensive assessments of: (1) cardiovascular parameters, (2) autonomic function, (3) body composition, (4) blood haematological and metabolic profiles, (5) cardiorespiratory fitness and (6) quality of life (QOL) and physical activity outcomes. Outcome measures will be assessed at baseline, 3 months, 6 months and 12 months (only QOL and physical activity outcomes). Statistical analyses will apply linear-mixed modelling to determine the training (time), group (ACET vs BWSTT) and interaction (time × group) effects on all outcomes. ETHICS AND DISSEMINATION: Ethical approval was obtained from all three participating sites. Primary and secondary outcome data will be submitted for publication in peer-reviewed journals and widely disseminated. TRIAL REGISTRATION NUMBER: NCT01718977; Pre-results. TRIAL STATUS: Recruitment for this study began on January 2013 and the first participant was randomized on April 2013. Recruitment stopped on October 2018.