There is no definitive answer to this question as different commercial gyms will use different brands and types of equipment. However, some of the more popular brands that are often used in commercial gyms include Precor, Life Fitness, Cybex and Hammer Strength. These brands offer a wide range of equipment, from treadmills and ellipticals to free weights and strength machines. Ultimately, the decision of what brand or type of equipment to use will come down to the individual gym's preference.