Hammer Strength Iso-Lateral Leg Curl

The Hammer Strength Plate Loaded Iso-Lateral Leg Curl is a leg curl machine that lets you train your hamstrings lying down, with its own work arm for each leg. Because you lie on your front your hips stay neutral, so you compensate less with your lower back and hip flexors and the load stays on the back of your thigh. Intended for the serious home gym, the personal training studio and the semi-professional space where leg training goes beyond squatting alone.

Iso-Lateral Leg Curl at a glance

• Independent work arms for each leg: left and right move separately, so your strong leg cannot take over the work of your weaker one.
• Four different ways to train: both legs together, alternating, one leg on its own or with a different weight on each side, so you can work a difference away deliberately.
• Work arms angled 4 degrees outwards: the path follows the natural position of your lower leg instead of forcing your knee into a straight line.
• Lying design: your hips stay neutral, so the tension stays where you want it and you do not pull along with your pelvis.
• Starting resistance of 0.9 kg per arm: unloaded, the machine moves almost weightlessly, which makes warm-up sets and small steps up worthwhile.
• 11-gauge steel frame with powder coating: heavy gauge steel with an electrostatically applied layer, built for daily use by several people.
• Four storage pegs on the frame: your plates sit on the machine rather than around the room, so changing between sets is quick.
• Rubber feet: the machine stays in place during a heavy set, even without anchoring.

Why iso-lateral makes a difference for hamstrings

On a leg curl with a single connected roller, your strong leg quietly takes over part of the work, and with hamstrings in particular that goes unnoticed for a long time. Here each leg moves separately, so in the last reps of a heavy set you feel straight away that one side is giving out sooner. And you can act on it: an extra set for the side that is lagging, or a different weight on each arm. Over a training block of a few months, that stops a difference from becoming permanent.

Training lying down rather than seated

The lying design is the main difference from a seated leg curl. On your front your hips stay in a neutral position, so your pelvis does not tilt along as soon as it gets heavy. The result is that the movement stays cleaner and that you feel the tension where you want it. The angle between the hip and chest pads opens out, so your torso is supported and your lower back has less to do during the final reps.

Choosing and building resistance

You load a maximum of three 10 kg plates per arm, on top of a starting resistance of 0.9 kg per arm. That sounds modest next to a chest machine, but on a curl the hamstrings work through a short lever: this range is plenty for almost everyone. The advantage of that low starting resistance is that you can begin very small, which is welcome if you are still learning the movement or building back up after a quiet period. Weight plates do not come with the machine.

Space and set-up

The machine measures 175 cm long, 145 cm wide and 104 cm high, and it weighs 130 kg. That build height of 104 cm is low for a strength machine, so a basement or garage with a lowered ceiling is rarely a problem here. Do allow clear space on both sides to slide plates on and off and to get onto it comfortably. At 130 kg unit weight plus the loaded plates, this is a machine for a permanent spot on a level, solid floor.

Worth knowing

This is a machine for a single movement. If you only have room for one or two machines, a multi gym gives you more exercises per square metre. The Leg Curl only becomes interesting once you are building leg training up seriously and the hamstrings are a fixed part of your schedule alongside squats and deadlifts. Bear in mind as well that you buy the plates separately for each side.

Frequently asked questions about the Iso-Lateral Leg Curl

How much weight can I load on this machine?

You load a maximum of three 10 kg plates per arm, on top of a starting resistance of 0.9 kg per arm. For a lying leg curl that is a generous range, advanced users included, because the lever on this movement is short. Because each side is loaded separately, you are effectively buying the weight twice. Weight plates are not supplied.

How does this differ from a seated leg curl?

The position. Lying down, your hips stay neutral, so your pelvis does not tilt along and you compensate less with your lower back. On a seated version your hip is bent, which loads the hamstrings at a different length. Plenty of people use both versions alongside each other, but if you pick one, the lying design gives the strictest movement.

How much space do I need?

The machine itself is 175 x 145 x 104 cm. With a build height of 104 cm it also fits a room with a lower ceiling, where taller strength machines will not go. Allow clear space on both sides as well, to change plates and to get on and off. Measure your floor before you order, because at 130 kg this is not a machine you shift in passing.

Is this machine suitable for beginners?

Yes, a guided movement is actually welcome for beginners because you do not have to stabilise the path yourself. With 0.9 kg starting resistance per arm you can learn the movement virtually unloaded and then build up in small steps. The lying position also makes it hard to cheat by pulling with your back. That said, this is professional equipment for a single exercise, so for someone just starting out it is a substantial investment.

Can I train with a different weight on each leg?

Yes, that is exactly what the independent work arms are there for. You load left and right separately, so a weaker side can do the same reps with less weight. You can also work alternately or train one leg on its own. That makes the machine useful when you want to tackle a clear left to right difference.

Do I have to anchor the machine to the floor?

That is not necessary. The machine stands on rubber feet and weighs 130 kg on its own, so it will not slide during a heavy set. More important is a level surface able to take the load, certainly on a wooden upper floor. Choose a final spot in advance, because moving it afterwards is no small job.