The smallest adjustments change the entire rep. The Nike Strength Pro Single Leg Roller rotates with the athlete through split squats, hip flexor work and rehab progressions, so the leg stays set instead of sliding a little on every rep and the focus stays on the movement. The roller runs a full 152 mm (6 inches) in diameter, wrapped in commercial-grade synthetic leather — firm enough to hold under load without bottoming out onto the structure underneath the way thinner rollers do, and wide enough to suit both regular and larger athletes. It is rated to 159 kg and tested to 635 kg to account for the athlete plus added weight. A knurled bolt makes height changes quick between athletes, with a nylon liner inside to protect the rack’s powder coat as it tightens down.