The erection of the male and female erectile organs (male and female penis) consists of three phases: a) latent, b) turgid, c) rigid or muscular. Ischiocavernosum muscles (muscles of erection) are much more developed in male than in female. These muscles are innervated by branches of the pudendal nerve, that originates from Onufʼs nucleus located in the sacral spinal cord. The androgens are responsible of the sexual dimorphism of this nucleus. The tonic contraction of ischiocavernosum muscles during erection is necessary for the rigidity of penis. These muscles, as also the bulbocavernosum muscle (muscle of ejaculation and orgasm), though histologically striated, have a semiautomatic function: ischiocavernosum muscles, together with bulbocavernosum muscle, introduce a continuous involuntary reflected hypertonic contraction during erection. This is necessary not only for the rigidity of the penis, but also for the maintenance of erection. The Kegel exercises allow the contraction of the pubovaginalis (elevator of the prostate in male) and the puborectalis muscles, and of all the perineal muscles and especially of the superficial ones (the most important in sexology): only with these exercises it is possible to train the ischiocavernosum and bulbocavernosum muscles.

This training could reduce the post-ejaculatory refractory period that increases in every man with age and could facilitate the erection after a first ejaculation. In elderly men the ejaculation takes place with less strength or without squirting. The Kegel exercises, training bulbocavernosum muscle, are important to prevent and postpose the physiologic reduction of the strength of ejection of the seminal liquid.