Powerhouse Gym 7435 Watson Rd, Saint Louis, MO63119 Powerhouse Gym is open 24 hours and someone is on staff around the clock. This is a large gym with plenty of equipment,…More including a variety of cardio workout machines and saunas for men and women. Childcare and classes are included with membership. Personal trainers are on staff and one free training session is available for new members. 2010 is the gym's 20th anniversary, and there are membership specials all year.