Hammer Strength Iso-lateral Leg Curl Both Leg is a hamstrings-focused exercise built around a pull pattern and performed with selectorized machine. The muscular job here is to contribute to the movement, and that translates directly into overall performance in this pattern. What separates this variation from other hamstrings work is that it is using a neutral hammer grip — a detail that changes which fibres take the load and how much stability the movement demands. The 'Hammer Strength Iso lateral' element in the name is the part that matters technically — it defines the exact position and path this version uses, and swapping it changes the training effect. Support comes from the calves and glutes; the calves in particular help point the foot downward at the ankle, which is why fatigue there often shows up before the hamstrings is fully worked. Training this with selectorized machine makes load changes instant and keeps the movement path stable, though it may not fit every limb length despite adjustment. Programme it alongside your other hamstrings work rather than as a standalone. The pattern is accessible enough to learn in a single session, which makes it a sound entry point before progressing to heavier or more complex variations.
Muscles Worked
The Hammer Strength Iso-lateral Leg Curl Both Leg is primarily a legs exercise, but it is never only the legs doing the work.
Legs
75%
Calves
42%
Glutes
32%
Legs (primary) — These fibres contribute to the movement, and they carry the majority of the load in this movement.
Calves (secondary) — Assists by helping to point the foot downward at the ankle, contributing to ankle stiffness, walking and jumping mechanics.
Glutes (secondary) — Assists by helping to extend and externally rotate the hip, contributing to hip power, posture and lower-back protection.
Benefits of the Hammer Strength Iso-lateral Leg Curl Both Leg
Uses selectorized machine, which makes load changes instant and keeps the movement path stable.
Reinforces the lats, mid-back, rear delts and biceps as a coordinated unit rather than as isolated parts.
Builds strength in the hamstrings through a pull pattern, which carries over directly to drawing resistance toward your torso.
Allows progressive overload — adding load or repetitions over weeks is what actually drives hamstrings growth.
How to Perform the Hammer Strength Iso-lateral Leg Curl Both Leg
1
Adjust the seat and handles so the machine's pivot lines up with your working joint.
2
Begin by drawing your shoulder blade toward your spine, then pull the handles toward you.
3
Pull until your hamstrings is fully shortened and hold that position for a beat.
4
A good Hammer Strength Iso-lateral Leg Curl Both Leg rep looks identical to the one before it; when it doesn't, the set is done.
5
Return to the start under control, letting the arm straighten without losing tension.
6
Keep every rep at the same tempo — when speed drops noticeably, end the set.
Your Goal General Fitness
Sets
2–3
Reps
10–15
Rest
60s
Breathing Technique
The general rule for the Hammer Strength Iso-lateral Leg Curl Both Leg is simple: inhale on the lowering phase, exhale as you pull. For heavier sets, take a breath in at the start position, brace as though bracing for a punch, and hold that pressure through the hardest part of the rep before exhaling. If your breathing falls apart, it is usually the first sign the set has gone past useful.
Tips for Proper Form
Set your position before the first rep rather than correcting it mid-set.
Keep the range of motion consistent across every rep so you can compare sessions honestly.
Maintain a neutral hammer grip throughout — letting it drift changes which muscles are loaded.
Lead with the elbow rather than the hand so the back does the work instead of the arms.
Control the lowering phase — most of the hamstrings stimulus comes from resisting the weight, not lifting it.
Pull to the point where your hamstrings is fully shortened, pause for a beat, then lower under control.
The Hammer Strength Iso-lateral Leg Curl Both Leg works best when you treat the hamstrings as the only muscle in the room — if you stop feeling it there, scale the movement back rather than pushing on.
Adjust the seat so the pivot lines up with your joint — a bad setting quietly moves the work off the hamstrings.
Common Mistakes to Avoid
Pulling with the arms before the shoulder blades move.
Do this insteadInitiate with the scapula, then bend the elbow — otherwise the hamstrings barely participates.
Treating the Hammer Strength Iso-lateral Leg Curl Both Leg as a warm-up movement and never progressing it.
Do this insteadGive it real working sets — the hamstrings needs a genuine stimulus, not a token effort.
Using momentum even though the machine removes the need for balance.
Do this insteadSlow the tempo — with stabilisation handled, the hamstrings should do all of it.
Variations by Experience Level
Beginner
Reduce the load and perform the Hammer Strength Iso-lateral Leg Curl Both Leg for higher repetitions, focusing entirely on position rather than weight. If selectorized machine feels unmanageable, rehearse the same pattern with bodyweight first. Stay at this level until every Hammer Strength Iso-lateral Leg Curl Both Leg rep looks the same as the first.
Intermediate
Add a one- to two-second pause at the hardest position of each repetition. Alternate harder and easier Hammer Strength Iso-lateral Leg Curl Both Leg sessions rather than pushing every one.
Advanced
Add a drop set on the last working set to extend the stimulus beyond your normal stopping point. At this level the Hammer Strength Iso-lateral Leg Curl Both Leg is best programmed after your heaviest hamstrings work, not before it.
Safety Considerations
Warm up with lighter sets of the Hammer Strength Iso-lateral Leg Curl Both Leg before your first working set.
The most common way the Hammer Strength Iso-lateral Leg Curl Both Leg goes wrong is using momentum from the lower back to swing the weight.
Stop the set when technique degrades — a Hammer Strength Iso-lateral Leg Curl Both Leg rep that no longer looks like your first one is not building anything.
Keep a neutral hammer grip consistent; changing it mid-set shifts load onto joints that are not warmed up for it.
Who Should Avoid This Exercise
The Hammer Strength Iso-lateral Leg Curl Both Leg suits most healthy trainees, but it is not appropriate for everyone.
Anyone with an acute lower-back injury or disc irritation, until cleared to load the spine again.
Anyone experiencing sharp, localised or radiating pain during the movement — that is a signal to stop, not to push through.
This is general educational information, not medical advice. If you are managing an injury or medical condition, check with a qualified professional before adding this exercise to your programme.
What muscles does the Hammer Strength Iso-lateral Leg Curl Both Leg work?
It primarily trains the legs, with the calves and glutes assisting. The pattern is classified as pull, so the lats, mid-back, rear delts and biceps share the workload.
Is the Hammer Strength Iso-lateral Leg Curl Both Leg suitable for beginners?
Yes. It is rated beginner-level, and the pattern can usually be learned in a single session with light resistance.
How many sets and reps should I do?
A practical starting point is 3 sets of 10-12, resting 60-90 sec between sets, roughly 2x per week. Adjust from there based on how you recover.
What equipment do I need for the Hammer Strength Iso-lateral Leg Curl Both Leg?
You need selectorized machine. This makes load changes instant and keeps the movement path stable, though it may not fit every limb length despite adjustment.
How do I breathe during the Hammer Strength Iso-lateral Leg Curl Both Leg?
As a general rule, inhale on the lowering phase, exhale as you pull. Avoid holding your breath for the entire set.
What is the most common mistake with the Hammer Strength Iso-lateral Leg Curl Both Leg?
Using momentum from the lower back to swing the weight. The simplest correction is to lead with the elbow rather than the hand so the back does the work instead of the arms.
What can I do instead of the Hammer Strength Iso-lateral Leg Curl Both Leg?
Good substitutes that train the same hamstrings pattern include Lying Single Leg Extended On Wall Hamstrings Stretch, Ankle - Dorsal Flexion, and Ankle - Plantar Flexion. Pick whichever matches the equipment you have available.
How do I progress the Hammer Strength Iso-lateral Leg Curl Both Leg over time?
Add a small amount of load once you can complete every set at the top of the rep range with clean technique. Keep tempo and range consistent so the comparison is honest.
About Training Your Hamstrings
Within hamstrings training, the Hammer Strength Iso-lateral Leg Curl Both Leg is the selectorized machine variation to reach for when you want a pull pattern you can repeat consistently.
The hamstrings run down the back of the thigh and perform two jobs: bending the knee and extending the hip. Strong hamstrings balance the quads, protect the knee, and are essential for sprinting and powerful hip extension.
Train them with two movement types. Knee-flexion work — lying and seated leg curls — targets the hamstrings directly, while hip-hinge movements like the Romanian deadlift, good morning, and Nordic curl load them through a powerful stretch. Combining both builds fuller, more resilient hamstrings than curls alone.
On hinges, push the hips back with a flat back and feel the stretch rather than rounding the spine. A slow lowering phase dramatically increases the training effect.