A perineometer or Kegel perineometer (vaginal manometer) is an instrument for measuring the strength of voluntary contractions of the pelvic floor muscles. Arnold Kegel (1894–1981) was the gynecologist who invented the Kegel Perineometer (used for measuring vaginal air pressure) and Kegel exercises (squeezing of the muscles of the pelvic floor). This followed the observation that muscles of the pelvic floor inevitably weakened following the trauma of childbirth. Ascertaining the air pressure inside the vagina by insertion of a perineometer, while requesting the woman to squeeze as hard as possible, indicates whether or not she would benefit from strengthening the vaginal muscles using the Kegel exercises. More modern electromyograph (EMG) perineometers, which measure electrical activity in the pelvic floor muscles, may be more effective in this purpose. Assessment of pelvic floor strength during gynaecological examination may help to identify women with fascial defects of the pelvic floor, as well as those at risk of genital prolapse or urinary incontinence. Both the Kegel perineometer and a digital examination are effective and concordant in their results in this assessment.