Heavy Duty Isolated Leg Extension - Curl MachineLeg Extension and Curl Machine with Single Leg Extension Isolation Feature Step up your leg game with our Heavy Duty Isolation Leg Extension Machine. This high quality equipment helps you work your quads and hamstrings effectively by isolating the muscles for maximum results. Whether you're targeting both legs or focusing on single leg extension, this plate loaded leg curl machine (330 lb. weight capacity) ensures youre always pushing your limits.