A Smith machine guides the barbell along a fixed vertical path, unlike a free-weight bench press. This fixed trajectory reduces the need for stabilizing muscles, simplifying the lift and potentially allowing for a heavier weight load. Consequently, the perceived exertion may be lessened compared to a traditional bench press.
This difference in muscular recruitment can be advantageous for individuals new to weightlifting or those rehabilitating from injuries, providing a more controlled environment. However, this very characteristic can also limit the development of stabilizer muscles crucial for functional strength and overall athletic performance. The reduced demand on these supporting muscles also alters the biomechanics of the exercise, potentially increasing the risk of shoulder impingement if proper form is not maintained. The history of the Smith machine, attributed to Jack LaLanne and later refined by Rudy Smith, underscores its evolution as an accessible strength-training tool.