The effect of inverted positioning on spinal length and electromyographic (emg) activity of superficial lumbar area musculature was investigated in 20 healthy men. Spinal length tape measurements were taken with subjects first sitting erect and after 1 minute in the inverted position. An integrated bioelectric monitoring system was used to quantify emg activity. Initially, a stable emg baseline was identified for each subject resting supine on a motorized tilt table. The randomly selected control group subjects remained supine for an additional 245 seconds. Experimental group subjects were inverted for half this duration and returned to the resting position for the remainder. Data were recorded for 10-second accumulation periods of emg activity 16 times from each subject. The 1-tailed paired t-test was applied to all data. The difference between the means of the spinal length measurements taken sitting and during inversion was highly significant (p less than 0.005). The difference between the mean emg activity of the inversion period and the baseline mean was also statistically relevant (p less than 0.03). This study concluded that inverted positioning for short periods significantly increased spinal length and reduced emg activity of the superficial lumbar area musculature of normal males. These findings complemented the clinical observations of several authors.