This study was to investigate the change of muscle fatigue through maximum contraction during flexion and extension of knee joint before and after the isometric trunk exercise was implemented on elderly Hansen`s disease. 18 subjects exercised for 60 minutes twice a week for 12 weeks. The subjects were divided into normal sensory group, group with sensory loss in left sole, group with sensory loss in right sole, and group with sensory loss in both soles, according to the sensory condition on their soles. We obtained following results. Muscle fatigue in normal sensory group, there were significant differences in left·right hamstring, left rectus femoris(p<.05), in group with sensory loss in left sole, there were significant differences in left·right hamstring(p<.05), in group with sensory loss in right sole, there were significant differences in left·right hamstring, right rectus femoris and group with sensory loss in both sole, there were significant differences in right hamstring(p<.05). The differences of muscle fatigue according to the sensory condition on their soles, there were significant differences in left hamstring between normal sensory group and group with sensory loss in both sole(p<.05).