Intelligent workload control of bicycle ergometer for the elderly based on individual physical work capacity

Studies on controlling the bicycle ergometer workload for middle-aged and elderly people by monitoring their heart rate and surface EMG during exercise have been conducted in the past. In this paper, it is shown that 18 middle-aged and aged subjects studied can he classified into four types in terms of time changes of the indices associated with muscular fatigue, as estimated by tests involving progressively increasing workload. In addition, customization of a workload-control method for middle-aged and aged people who show large individual differences in physical work capacities is discussed on the basis of tests of 8 subjects selected from the above types, conducted five times over 9 months. Specifically, scatter graphs of indices associated with muscular fatigue and heart rates measured during progressively increasing workload tests were divided into three intervals and a membership function was designed for fuzzy workload control for each of these intervals. In addition, fuzzy rules considering subjective indices and anaerobic work thresholds are studied while increasing the workload temporarily. The results show that a workload control method that guarantees safety and a feeling of accomplishment can be developed for exercise in the vicinity of the threshold of anaerobic metabolism. (C) 2004 Wiley Periodicals, Inc.