For the reconstruction of anal function for fecally incontinent patients, it could be practicable to transpose the gracilis muscle around the anal canal, with electrical stimulation to maintain contraction. It is necessary to keep continuous tonus, so tetanic contraction or "summation" would be essential for fecal continence, with a stimulation which permits prolonged contraction. Transposition of the gracilis muscle around the rectum was performed in thirteen Japanese white male rabbits. The muscles of the conditioning group (n = 8) were stimulated at 10 Hz for 6 weeks before the procedure. By stimulation at 15 Hz, a low frequency to permit prolonged contraction, the neoanal pressure increased maximally to 134.2 +/- 55.6 cmH2O (mean +/- s.d.) in the conditioning group, and to 115.0 +/- 37.1 cmH2O in the non-conditioning group (n = 5) (N.S.). But, the basal pressure with stimulation rose 82.3 +/- 12.4% (mean +/- s.d.) of the increase in the conditioning group, while that of the non-conditioning group remained at resting pressure (p < 0.001). The conditioning made it possible for the rabbit's gracilis muscle to create anal pressure with a sufficient rise in the basal pressure at a frequency permitting prolonged contraction.