If a person is able to do so without injury or pain, optimal results would be found when using what over what?

The choice of using free weights over machines is supported by the idea that free weights promote the use of multiple muscle groups and assist in improving coordination, balance, and functional movements. When exercises are performed with free weights, the individual engages stabilizing muscles to maintain control and stability throughout the movement, thereby enhancing overall strength and proprioception.

Free weights also allow for a greater range of motion and flexibility in movement patterns, accommodating natural body mechanics better than machines, which often have fixed paths of motion. This adaptability can lead to better muscle activation and development, as well as enhance the ability to perform everyday activities.

While machines can be beneficial for isolating certain muscle groups and may provide a safer environment for those beginning their strength training journey, they do not typically engage the body in the same multilateral fashion that free weights do, resulting in less functional strength gains over time. Free weights tend to provide a more comprehensive approach to resistance training for those who can perform the movements safely and effectively.