Repetitive skill deterioration with fast and exercise-lowered blood glucose

Using a computerized system for measurement of the variability of force exerted at 26 points in each pedal revolution during the repetitive habituated task of cycling, healthy adult males 6 times performed for 20 minutes, either (a) 3 hours after a meal (fasting) or when so fasted and then fed glucose (b) immediately before, or (c) 30 minutes before performance. Both light and moderate workloads were used. As expected, blood glucose concentrations fell modestly below basal with exercise under (a) or (c) but not under (b). ANOVA of force mean and variability statistics significantly contrasted the 3 treatments, and 2 linear functions from multivariate analysis showed (a) and (c) to be significantly different from (b). These two treatments depressing blood glucose were more variable in force applied, with altered pattern of average forces, especially for points in the task where changes occurred in the force/time relationship. These points may use more immediate feedback correction. Such deterioration of movement control has significant applied implications and invites study of its neural aetiology.