We used a tightly woven cotton belt 13.5 cm (5.3 inches) in width, which was tied around a patient in an electrical wheelchair to help maintain him in the upright position. The belt was positioned between the fourth/fifth and eighth/ninth ribs anterior to the axillary line of the patients. With the aim of assessing the effects of belt position on the efficacy of RBP, we compared respiration with the belt in its usual position and positioned 10 cm (3.9 inches) cephalad. Breath-to-breath ventilation and expiratory gases were measured with a respirometabolic monitoring system (MG-360, RM-300; Minato; Osaka, Japan) through a full face- mask. The subjects were six patients with DMD, 22 to 35 years of age, who were unable to ambulate and were dependent on mechanical ventilation 50 to 100% of the time. They started spontaneous RBP as soon as they were transferred from the bed to an upright position in a wheelchair with the ventilator temporarily stopped. During RBP with the belt in its usual position, tidal volume was 276 ± 69 mL per breath (mean ± SD) and respiratory rate was 30.3 ± 7.0 breaths/min. However, with the belt in the more cephalad position, tidal volume was significantly decreased, to 232 ± 71 mL per breath (p < 0.05), without any change in respiratory rate of 31.0 ± 7.8 breaths/min. The supplemental tidal volume exerted by an efficient RBP in these patients was approximately 20%. With the unusual belt position, all the patients felt uneasy on breathing due to a lack of freedom to utilize their upper body for RBP.