An investigation of the effect of a six-minute manual muscle massage on the excitability of the spinal reflex pathway in 20 able-bodied subjects was undertaken. H-reflex recordings were obtained from the right soleus muscle, which was the site being massaged. Skin temperature and antagonist activity were monitored in an attempt to explain the changes observed in a previous study. The experimental paradigm chosen was an A-B-A interrupted-time series design consisting of two pretreatment, two treatment (massage), and two posttreatment conditions. H-reflex amplitudes recorded during both massage conditions (.76 +/- .58 mV, .76 +/- .61 mV) were significantly reduced (F5,90 = 69.04, p less than .01) in comparison to all other (before and after) conditions (2.58 +/- .75 mV, 2.56 +/- .71 mV, 2.82 +/- 1.14 mV, and 2.89 +/- .82 mV, respectively). This decrease could not be explained conclusively by changes in skin temperature, nerve conduction velocity, or antagonist recruitment, thus indicating a decrease in spinal reflex excitability attributed to massage. These findings also support our earlier report, which stated that H-reflex amplitudes are reduced only during the period of tissue manipulation, regardless of the duration of the massage.