10/25/2026
We've added a new sign to the Nautilus Next Gen Leg Extension. This is actually one of the best leg extension machines because the strength curve on the machine is optimized for maximum time under tension but like all machines you have to use it correctly to get the full benefit. I see many people (not just in the gym but also online as I searched for tutorial videos) do this exercise incorrectly and there is misinformation online for what makes a good leg extension machine. The challenge is at the BOTTOM (the starting position), not the TOP, of the rep (when your legs are fully extended). If the strength curve remained consistent for the entire rep range then you'd damage your knees when you fully extend your legs.
The only way that you put resistance on your quads when your legs are extended at the TOP of the rep is when you pause the rep for a couple seconds -- it is because the resistance vanishes at the top of the rep range that some people "smash" the top of the machine lever when they fully extend their legs. It's very noisy and loud when people do this and can be heard from across the gym even by people wearing headphones. I hear it ALL THE TIME when people use this machine ,and it DAMAGES the metal gears and bike chain belt in the machine when people do that because they are trying to over-extend the machine beyond its intended range of motion. The resistance is supposed to get easier at the TOP of the rep so you don't hurt your knees, and you're intended to pause at the top of the rep range for 1-3 seconds, too. If you hear any banging at the top of the rep you are going up too far to where you lost resistance on your quads.
You as the user need to limit your rep range so you don't fully extend your legs all the way out, but instead keep your knees at a position so you keep tension on the quads. And once getting to this top range you should pause for 1-3 seconds before you slowly lower the weight stack back as you return to the starting position range. If you do leg extensions this way with suitable resistance your quads will BURN like they are on fire. You should feel like fire ants are biting your quads if you are doing the leg extension correctly. If you don't feel that intense burn in the quads then you are wasting your energy on the leg extension machine. I can tell when people are not doing this correctly because they are swinging their legs wildly, making a lot of noise but not actually working their quads. Then they pull out their phones or chat with people. If you do leg extension correctly you need a moment to get your thoughts in order because the discomfort on your quads is so much. It is a large muscle group so when you exhaust them, you feel it. It is one of the few exercises where if you do it correctly it's actually very uncomfortable.
The Leg Extension is a deeply isolating exercise and if you perform it correctly you should have trouble walking for a few moments after finishing your set, because your quads are exhausted. If you can hop off the leg extension and walk normally you did not perform the exercise correctly.
Also, ignore the handles on the seat and just cross your arms like a vampire, and keep your back perfectly still. Many people cheat the exercise by trying to swing their backs against the back pad to get the weight up past the starting position, or because the weight is so much it is lifting them out of the seat because their quads cannot get the weight up from the start position. That is your signal the weight stack is too heavy for you. Again, the fully extended position is the LEAST CHALLENGING part of the motion and is not actually the exercise. The challenge of the exercise is to lift the weight from the starting position so if you use body momentum to lift the stack up then you're cheating the exercise.
The exact amount of weight that you use on this machine is going to vary not just depend upon how strong you are but also how you are using it as part of your program. Nautilus machines were designed as part of a circuit. Many people like to use leg extensions to pre-exhaust their quads before they do another compound movement such as a squat or a leg press. However the original Nautilus program the leg extension was performed after doing compound leg movements. There's also a unit where leg extensions were built into a leg press machine so you would superset leg press and leg extension together.
So if you've already exhausted your quads some by doing another compound movement you're not going to need to use as much weight as when you are using it as the first leg exercise. This is something that you should consider as part of your program.
We've actually added a specially designed HUSLA pad to this machine to help increase tension on the quads at the bottom and top of the range, and again these pads are designed because a good leg extension will lose a lot of tension at the top of the range so you don't damage your knees. You don't have to use the extra padding, you can rotate the pad to not use the extra cushioning without removing the pad from the machine but it's there if you want some additional tension at the start and top of the exercise.