Free-weight machines often deliver less resistance at the start of the movement, which can under-load the initial range in the leg extension. Our dual loading axis corrects this bias: it lets you adapt the resistance to your profile and your goals. The result: more even tension across the whole movement, or targeted on the zone you want, ideal for the quadriceps (extension) and the hamstrings (curl), in controlled strength work or in volume.
Dual loading axis, an optimal resistance curve
Unlike basic models, this Leg Curl Machine features a double loading axis allowing fine adjustment of the resistance curve. This system corrects the tension losses often observed at the beginning of movement on classic machines.
Spread the plates between the low axis and the high axis. On leg extension, start with 65/35 (low axis / high axis) if you lack tension at the start. A distribution of 55/45 or lower is strongly discouraged. The second pin loads the machine from the very start, in the stretched position, a key phase for hypertrophy, where a classic leg curl gives little tension. With two pins instead of one, it also holds more plates, up to 140 kg.
It thus constitutes an excellent leg extension / leg curl machine for:
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maintaining continuous tension throughout the range of motion,
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better targeting the hamstrings and quadriceps,
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adapting the work according to your goals (hypertrophy, control, strengthening).
Leg curl and leg extension on a single machine
One machine to isolate the quadriceps (leg extension) and the hamstrings (leg curl). Footprint 124 x 91.4 x 113 cm for 41 kg, 140 kg capacity. It takes Olympic Ø 50 mm plates or standard 28/30 mm plates with the included adapter. To switch from leg curl to leg extension, simply change the position of the pins relative to the central bar.
Technical characteristics of the Leg Curl Machine
| Characteristic |
Detail |
| Type of machine |
Seated Leg Curl & Leg Extension |
| Load system |
Double independent loading axis |
| Plate compatibility |
Olympic Ø 50 mm + standard 28/30 mm (adapter included) |
| Backrest adjustment |
Multi-positions (knee alignment / rotation axis) |
| Seat adjustment |
Adjustable depth |
| Shin roller |
Automatically adjustable |
| Range-of-motion selector |
Start / end of stroke stops |
| Load capacity |
140 kg |
| Dimensions (L × W × H) |
124 × 91.4 × 113 cm |
| Machine weight |
41 kg |
| Frame |
Thick steel, wide base |
| Safety |
Non-slip / non-marking pads |
Standalone machine or CS-1 rack attachment?
Without a rack, choose this standalone dual-axis machine (140 kg, Olympic or standard plates). If you have a 75 x 75 mm rack with 25 mm holes, the CS-1 leg curl / extension attachment mounts on the rack (300 kg, Olympic plates, 19 kg).
Leg Curl Machine for targeted leg work
The UniStrength Leg Curl Machine is one of the essential strength training machines for effectively developing the lower body. It allows precise work on the hamstrings and quadriceps thanks to a combined leg curl and leg extension configuration, ideal for completing a home gym or equipping a professional gym.
Designed to integrate into a complete range of strength training machines, it offers a high-performance alternative to free exercises when the goal is muscle isolation, joint safety, and controlled progression.
Why choose the Uni Strength leg curl machine?
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Targeted and balanced leg work
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Fluid biomechanics and homogeneous tension
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Precise adjustments for all body types
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Compatible with standard and Olympic plates
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Ideal for completing a range of strength training machines
Learn all about the Leg Curl exercise
Frequently asked questions
What are the specifications of the seated leg curl and extension machine?
Dimensions 124 x 91.4 x 113 cm, weight 41 kg, load capacity 140 kg, thick steel frame with a wide base, non-slip feet. Compatible with 50 mm Olympic and 28/30 mm standard plates with the supplied adapter.
What is the dual loading axis?
Two plate pins that let you spread the load between two axes and modulate the resistance curve over the whole range, where classic free-weight machines lack tension at the start of the movement.
Which load distribution should be chosen between the two axes?
Start with 65/35 (low axis / high axis) on leg extension if there is a lack of tension at the start. A distribution of 55/45 or lower is strongly discouraged.
Which settings does the machine offer?
Multi-position backrest to align the knee with the axis of rotation, seat adjustable in depth, self-adjusting shin roller and range selector with start and end stops.
How should you position yourself on the machine?
Align the machine's axis of rotation with the knee joint before starting.
Which muscles and goals can you train with the leg curl and extension machine?
It isolates the quadriceps on leg extensions and the hamstrings on leg curls, for hypertrophy, controlled strength or strengthening work. It is an alternative to free weight exercises when you want muscle isolation, joint safety and controlled progression, in a home gym or a professional gym.
What is the difference with the CS-1 leg curl / extension attachment?
The Seated Leg Curl & Extension Machine is standalone, with a dual loading axis, for 140 kg and Olympic or standard plates (adapter included). The CS-1 leg curl / extension attachment mounts on a 75 x 75 mm rack with 25 mm holes, takes Olympic plates and supports up to 300 kg.
Which plates can be loaded on the machine?
Olympic Ø 50 mm plates, or standard 28/30 mm plates with the included adapter, up to 140 kg.
Are plates included?
No, the machine is delivered without plates. It takes Olympic Ø 50 mm or standard 28/30 mm plates (adapter included).
