Leg extensions are a strength training exercise primarily targeting the quadriceps muscles located at the front of the thigh. This exercise is typically performed using a leg extension machine, where the individual sits with their back against a padded support and extends their legs against resistance. The movement involves straightening the knees while keeping the upper legs stationary, which isolates the quadriceps. Leg extensions can help improve muscle strength, enhance athletic performance, and support rehabilitation efforts for knee injuries when performed correctly and with appropriate weight.