In order to investigate how the diaphragm and trunk muscles are recruited during various voluntary movements, we recorded EMG signals and video images simultaneously and analyzed EMGs of the diaphragm and trunk muscles during the voluntary movements that required trunk muscles. During trunk movements, the duration of the diaphragmatic activity became irregular and the intensity of the activity increased. Further analysis revealed that the diaphragmatic activities were consisted of two components, such as respiratory and non-respiratory activities during voluntary movements. Our results led to the idea that the diaphragmatic activities may be controlled from different control mechanisms of central nervous system.