This type of exercise equipment isolates and strengthens the muscles of the posterior and anterior thigh. A seated or lying user performs a controlled movement, flexing and extending the knee joint against resistance provided by weights or other mechanisms. Variations exist to accommodate different body types and training goals, such as prone, seated, and standing designs.
Developing strong hamstrings and quadriceps contributes significantly to overall lower body strength, stability, and athletic performance. It plays a key role in injury prevention, particularly for athletes engaged in activities requiring running, jumping, or rapid changes in direction. Rehabilitation protocols frequently incorporate this equipment for recovering from knee injuries or surgeries. Historically, simpler forms of these exercises were practiced with resistance bands or bodyweight, but dedicated machinery has evolved over time to offer more precise and controlled training.