Proof3

Proof3 is a small-group strength training gym in Scottsdale for adults who want to build muscle, protect bone density and stay strong as they age. Groups hold 12 people at most, often fewer, and each 60-minute session includes 30 minutes of strength work and 30 minutes of endurance. Working weights come from each member's own testing rather than a shared class workout, and the gym also offers personal training, online coaching and muscle preservation programs.

Every new member starts with the proof3 Assessment, which covers InBody body composition, movement screening and strength and power testing, producing a prf score that is retested over time. A coach goes over the results in a private 60-minute session before group training begins. Membership runs $249 to $299 a month after the first 30 days, and the gym sits in the Salt River area of north Scottsdale. Classes run seven days a week, with early morning and evening times.