We studied the voluntary contractile activity of the ischiocavernosus muscl
e (ICM) in 21 sexually potent and 97 erectile dysfunction (ED) subjects usi
ng a spring balance. A strap was placed around the coronal grove of the gla
ns penis and tensioned with the spring balance. Subjects were asked and enc
ouraged to contract the ICM against the spring balance. We evaluated the le
ngth of stroke, duration of contraction, and maximum contractile force. The
length of stroke, duration of contraction, and maximum contractile force s
howed statistically significant differences between potent and ED subjects.
Diagnosed psychogenic ED and arteriogenic ED showed higher contractile act
ivity than cavernous ED and neurogenic ED. Our results corresponded to thos
e of previous studies that have ur-ed consideration of the role of the ICM
during the process of erection in animal experiments and in human electroph
ysiological studies. The spring balance evaluation is a useful, inexpensive
method for evaluating the ICM.