Effect of pre-exercise carbohydrate ingestion on substrate consumption in persons with spinal cord injury

To investigate the influence of pre-exercise carbohydrate ingestion on fat and carbohydrate oxidation during prolonged arm cranking exercise in persons with spinal cord injury.

Six male paraplegic subjects (PS, Ll-Th3, 46.3+/-6.6 years) and seven able-bodied subjects (AB, 43.1+/-4.6 years) were volunteered to participate in the present study.

The subjects were required to consume a glucose solution (1 g kg(-1) body mass and 500 ml plain water; glucose experiment) or only plain water (water experiment) before the prolonged exercise. Then the subjects performed for 1-h arm cranking exercise at a moderate workload.

In the water experiment, the carbohydrate oxidation slightly decreased and the fat oxidation increased continuously in AB. In contrast, the carbohydrate and fat oxidation of PS was constant during the exercise in the water experiment. In the glucose experiment, the fat oxidation did not rise and the carbohydrate oxidation was constant until the end of the exercise in PS and AB. PS oxidized more fat than AB in the glucose experiment (P<0.05), but no significant difference was found between PS and AB in the water experiment.

Using a wheelchair in daily life regularly was regarded as an exercise training that disciplined PS indirectly and is considered to cause PS to have more percentage of type I fiber than AB in the anterior deltoid muscle. Thus, the distribution of muscle fiber type in anterior deltoid muscle might be one of the factors that impacted the fat oxidation of PS in glucose experiment.