Increased Fat Oxidation During Arm Cycling Exercise in Adult Men With Spinal Cord Injury Compared With Noninjured Controls

Abstract

People with spinal cord injury (SCI) tend to be more sedentary and increase fat accumulation, which could have a negative influence on metabolic flexibility. The aim of this study was to investigate the capacity to oxidize fat in a homogenous sample of men with thoracic SCI compared with healthy noninjured men during an arm cycling incremental test. Forty-one men, 21 with SCI and 20 noninjured controls, performed an incremental arm cycling test to determine peak fat oxidation (PFO) and the intensity of exercise that elicits PFO (Fatmax). PFO was expressed in absolute values (g/min) and relative to whole-body and upper-body lean mass ([mg·min−1]·kg−1) through three different models (adjusting by cardiorespiratory fitness and fat mass). Gross mechanical efficiency was also calculated. PFO was higher in SCI than in noninjured men (0.27 ± 0.07 vs. 0.17 ± 0.07 g/min; 5.39 ± 1.30 vs. 3.29 ± 1.31 [mg·min−1]·kg−1 whole-body lean mass; 8.28 ± 2.11 vs. 5.08 ± 2.12 [mg·min−1]·kg−1 upper-body lean mass). Fatmax was found at a significantly higher percentage of VO2peak in men with SCI (33.6% ± 8.2% vs. 23.6% ± 6.4%). Differences persisted and even increased in the fully adjustment model and at any intensity. Men with SCI showed significantly higher gross mechanical efficiency at 35 and 65 W than the noninjured group. Men with SCI showed higher fat oxidation when compared with noninjured men at any intensity, even increased after full adjustment for lean mass, fat mass, and cardiorespiratory fitness. These findings suggest that SCI men could improve their metabolic flexibility and muscle mass for greater efficiency, not being affected by their fat accumulation.

Fat Oxidation during Exercise in People with Spinal Cord Injury, and Protocols Used: A Systematic Review

“…Six of the included studies had observational cross-sectional designs [ 28 , 29 , 30 , 31 , 32 , 33 ], while two were clinical trials [ 33 , 34 ]. Four of the observational studies had a control group [ 29 , 31 , 32 , 33 ].…”

“…Six of the included studies had observational cross-sectional designs [ 28 , 29 , 30 , 31 , 32 , 33 ], while two were clinical trials [ 33 , 34 ]. Four of the observational studies had a control group [ 29 , 31 , 32 , 33 ]. One of the clinical trials had a crossover design [ 34 ], while the other was a parallel-group study [ 35 ].…”

“…The total population of all of the studies was 91 subjects of both sexes (84 men and 7 women) and >18 years old (range: 22 to 64 years). Of the total of 91 participants, 85 subjects with SCI were included—in some studies exclusively [ 28 , 33 , 34 , 35 ], and in others as a majority alongside other pathologies such as poliomyelitis (n = 1) [ 30 ], spina bifida (n = 3) [ 29 , 30 ], or limb amputation (n = 3) [ 29 , 31 ]. Four studies [ 29 , 31 , 32 , 33 ] included non-injured subjects as a control group (n = 45; 44 men, 1 woman).…”

“…Three of the studies were conducted on athletes competing nationally and internationally [ 29 , 30 , 31 ] in different disciplines: wheelchair racing [ 29 , 30 ], handcycling [ 29 , 31 ], and triathlon [ 31 ]. All of the studies except that of Jacobs et al (2021) [ 34 ] provided absolute values of VO 2peak , and all except that of Kressler et al (2012) [ 28 ] also offered values relative to body mass [ 33 , 34 ]. Thus, the mean value of VO 2peak was 1.86 L∙min −1 , although the range was between 0.75 and 2.60 L∙min −1 , where the lowest value corresponded to subjects with tetraplegia [ 35 ].…”

“…Arm cycle ergometer: This can be synchronous (i.e., the two arms of the ergometer are in the same position) or asynchronous (i.e., the arms of the ergometer are placed in opposite positions). Synchronous movement has been shown to be more efficient [ 37 ], although the most common system used in the laboratory is asynchronous [ 29 , 32 , 33 , 37 , 38 , 39 , 40 ].…”