GM45 Leg Extension / Wholesale, Bulk Supply & OEM for Commercial Gyms, Fitness Studios and Rehabilitation Centers

A Selectorised Isolation Machine for the Quadriceps

The GM45 Leg Extension is a single-purpose isolation machine for the quadriceps, built around a seated configuration with a selectorised weight stack. At 1242 × 1205 × 1296 mm, it shares the same footprint as the GM44 Seated Leg Curl in the same product range, which makes the two machines a matched pair for a leg-training line.

The specification sheet supplies the model designation in English and Chinese, an illustration of the machine, and the dimensions. The illustration shows a selectorised weight stack, a backrest, a seat, a leg pad, and handles. These visual details are sufficient to determine the machine category, but they do not describe the adjustment system, the stack weight, the increment value, or the frame specification. Buyers should request a complete specification sheet before quotation.

The distinction between a selectorised leg extension and a plate-loaded version is operational rather than functional. A selectorised machine allows the user to change the load with one pin movement. That reduces the time between sets from approximately 30–45 seconds to under five seconds and removes the handling requirement for weight plates. In a commercial gym, that difference determines how many members can use the machine during a peak hour.

For a rehabilitation setting, the selectorised system is the reason the machine is specified. Load can be increased in 2.5–5 kg increments, which is finer than the smallest standard weight plate. A patient returning from injury can progress without making a 10 kg jump, and the clinician can prescribe a specific load without relying on the patient to load plates correctly.

Why the Leg Extension Remains in Every Commercial Facility

The knee-extension movement isolates the quadriceps through the terminal range of knee extension. It is one of the few exercises that loads the quadriceps without requiring axial loading through the spine, and that distinction determines where the machine is used.

A squat or a leg press loads the entire lower body and places compressive load on the lumbar spine. For a member with a back injury, those movements may be contraindicated even when the legs have recovered. The leg extension allows the lower body to be trained independently of the spine, which makes it a standard rehabilitation tool.

The movement also trains the rectus femoris through its full length-tension relationship. The rectus femoris crosses both the hip and the knee, and it is active in both knee extension and hip flexion. In a seated position with the hip flexed, the rectus femoris operates from a pre-stretched position, which produces a different training stimulus from a squat.

For a commercial gym, the leg extension serves a different purpose. It is the primary isolation movement for the quadriceps and the standard exercise for addressing a strength imbalance between the anterior and posterior chain. A leg-training area built around squats, leg presses, and leg curls without a dedicated knee-extension station will leave the rectus femoris undertrained relative to the hamstrings.

The selectorised format also removes the technique barrier. A member can learn the movement in one instruction and perform it correctly thereafter. There is no bar path to learn, no rack position to establish, and no stabilisation requirement.

1242 × 1205 × 1296 mm on the Training Floor

The assembled dimensions are 1242 × 1205 × 1296 mm. At 124.2 cm long, 120.5 cm wide, and 129.6 cm high, the GM45 occupies 1.50 square metres​ of floor space.

That footprint is identical to the GM44 in the same range, which is not coincidental. A matched pair should occupy the same floor area so that they can be placed side by side without one machine projecting into the walkway. For a distributor or facility planner, this consistency simplifies the layout: two machines, two identical footprints, one leg-training corner.

The 129.6 cm height clears standard ceiling heights without issue and allows the machine to be placed beneath overhead rigging or wall-mounted storage in most facilities. The weight stack and the top of the movement arm should be checked against any overhead obstruction, but at 129.6 cm the clearance requirement is minimal.

The 120.5 cm width is the figure that requires planning. At 120.5 cm, the GM45 is 25–30 cm wider than the 90–95 cm width of a standard power rack. The working clearance must be added on both sides: access to the weight stack on one side, and clearance for the user to enter and exit the machine on the other.

A practical planning rule is to allow 0.60–0.90 metres​ of clearance on the stack side and 0.60–0.90 metres​ on the entry side. That gives a required zone of approximately 2.40–3.00 × 2.40–3.00 metres for safe operation, which is substantially more than the 1.50 square metres of the machine footprint.

The machine should not be placed against a wall on the stack side. A member selecting a weight must be able to stand alongside the machine without contacting another user or piece of equipment. This is a layout error that appears in newly equipped facilities and creates ongoing congestion complaints.

The Selectorised Stack and the Increment Question

The GM45 is shown with a selectorised weight stack. The specification sheet does not state the stack weight, the increment value, or the number of plates in the stack, and these are the three figures that determine whether the machine is suitable for the intended user base.

A standard commercial leg-extension stack ranges from 60 kg to 100 kg, with increment values of 2.5 kg, 5 kg, or 10 kg depending on the plate configuration. The increment value is the more important figure for a rehabilitation setting: a 10 kg jump is unusable for early-stage recovery, while a 2.5 kg increment allows measurable progression.

Buyers should request the following in writing:

• Total stack weight and the effective resistance at the movement arm
• Increment value per plate
• Number of plates in the stack
• Whether the top plate is a half increment
• Whether the stack is fitted with a magnetic selector pin
• Whether the stack enclosure is included

The distinction between stack weight and effective resistance matters. A lever system changes the mechanical advantage through the range of motion, so the weight selected on the stack is not necessarily the force applied to the leg pad. For a rehabilitation clinician prescribing a specific load, this difference must be known.

The stack enclosure is a safety item rather than a cosmetic one. It prevents a plate from being selected while the stack is in motion and protects users from pinch points. It should be confirmed as included before the order is placed.

Adjustment System and the User-Height Range

The leg-extension movement requires the leg pad to contact the anterior ankle at the correct distance from the knee joint. If the pad is too far forward, the resistance curve changes and the terminal range becomes difficult to control. If the pad is too far back, it contacts the shin rather than the ankle.

The GM45 illustration shows a seat, a backrest, and handles, but does not show the adjustment mechanism. Buyers should request the adjustment range for the seat position and the leg-pad position, and should confirm the mechanism type.

A pop-pin adjustment is the commercial standard. It allows the user to make the change from the seated position without tools and without assistance. A bolt-and-hole system requires the user to stand and manipulate a threaded fastener, which is slower and produces more service calls.

The user-height range should also be confirmed. A commercial leg extension should accommodate users from approximately 150 cm to 200 cm in height. The GM45 illustration shows a frame that appears to support this range, but the specification should be requested in writing.

The backrest angle is the other adjustment that affects the movement. A more reclined backrest changes the hip angle and alters the length-tension relationship of the rectus femoris. For a rehabilitation setting, a fixed backrest at a defined angle is preferable to an adjustable one, because it removes a variable from the exercise prescription.

Upholstery, Frame Finish and the Daily-Use Standard

The GM45 is shown with black upholstery and a grey frame. The visual specification is not a technical detail: it determines whether the machine can be integrated into an existing colour scheme and whether the finish will survive daily use.

For commercial use, the frame should be finished in a two-coat powder system over shot-blasted steel. A single-coat or painted finish will chip at contact points within the first six months of operation. The welds at the main frame joints should be continuous and ground flush, and the frame tubing should be of a gauge appropriate to the rated load.

The upholstery should be high-density foam covered in a commercial-grade vinyl with double-stitched seams. The foam density determines whether the pad deforms under load, and the stitching determines how long the cover remains intact. Both should be confirmed by requesting material samples before a bulk order is placed.

The leg pad should be positioned to contact the anterior ankle without impinging on the tibial tuberosity or the medial knee structures. The pad should be contoured rather than flat, as a flat pad tends to roll off the ankle during the terminal extension phase.

The handles should be positioned so that the user can stabilise the upper body without elevating the hips during the movement. If the handles are too far forward, the user will lift the pelvis to reach them, which removes the lumbar support that the backrest provides.

GM45 Against the Category

The following table draws on specification sets published by manufacturers operating in the same commercial strength-equipment category. Where competing figures differ, the lower or more conservative value is shown so the comparison remains fair.

The comparison that matters is not the footprint. It is the combination of a seated selectorised configuration, a shared footprint with the GM44, and the absence of a stated stack weight — which means the procurement decision should be delayed until the full specification is received.

Procurement and the Quotation Package

A distributor sourcing the GM45 should request a complete quotation package rather than a unit price. The minimum information required is:

• Full frame specification, including tubing dimensions and steel thickness
• Powder-coat specification and colour options
• Upholstery material, foam density, and colour options
• Weight-stack weight, increment value, and plate count
• Adjustment range for the seat and the leg pad
• Backrest angle and adjustability
• Rated load capacity
• Net, gross, and carton or crate dimensions
• Unit count per 20-foot and 40-foot container
• Spare-parts list and recommended stock levels
• Warranty terms, separated by frame, upholstery, and components
• OEM and private-label options, including logo application and colour matching
• Minimum order quantity and lead time

The last item is material. A facility equipping a new floor may require a matched set across multiple pieces, and the colour and finish must be consistent across the order. The grey frame and black upholstery shown in the specification sheet should be confirmed as standard or optional before the order is placed.

Container Loading and Stock Economics

The GM45 footprint of 1242 × 1205 × 1296 mm suggests a carton or crate in the region of 1300–1400 mm in length, 1250–1350 mm in width, and 900–1100 mm in height. The exact dimensions and gross weight are not listed on the specification sheet and should be requested from the factory before production begins, along with a loading diagram and the exact unit count per container.

Based on these indicative figures, the realised unit count in a 20-foot container will be modest. A 20-foot container offers approximately 33 cubic metres of internal volume, and the gross weight of each crate must also be confirmed, as the 216 kg GM44 net weight in the same range indicates that the gross figure will be substantially higher.

For a distributor, this argues for consolidating strength-equipment orders across multiple SKUs rather than shipping single units. The freight cost per unit decreases materially when the container is filled with a matched range rather than a single machine.

Maintenance and the Failure Points

Selectorised equipment has more service items than plate-loaded equipment, and the maintenance schedule should be documented from the date of installation.

A workable schedule for the GM45:

• Daily:​ wipe the upholstery, the frame, and the weight stack. Sweat is corrosive and the largest single cause of premature frame and upholstery failure.
• Weekly:​ inspect the selector-pin engagement and confirm that the pin sits fully home in the plate. A partially engaged pin will damage the plate and create a drop hazard.
• Monthly:​ check the cable tension and inspect the cable for broken strands. A cable with more than two broken strands should be replaced immediately.
• Quarterly:​ lubricate the guide rods with a dry-film lubricant. Do not use oil-based products, which attract abrasive dust and accelerate wear on the stack plates.
• Every six months:​ inspect the movement-arm pivot for play. Any lateral movement indicates bearing wear and should be addressed before the pivot housing is damaged.

The cable is the single component that determines whether the machine remains usable. A frayed cable changes the resistance curve and can fail under load. For a commercial facility, the recommended spare-parts stock should include one complete cable and one selector pin per machine.

Where the GM45 Belongs

The GM45 is suited to commercial gyms, rehabilitation centres, physiotherapy clinics, hotel fitness rooms, corporate wellness facilities, and fitness studios. It is a single-purpose machine, and it should be specified as part of a leg-training line rather than as a standalone purchase.

For a commercial gym, the GM45 provides the quadriceps component that pairs with the GM44 leg curl to form a complete knee-joint training station. For a rehabilitation centre, the selectorised stack allows load progression in small increments without plate handling. For a studio, it provides a low-coaching machine that members can operate without supervision.

The GM45 should not be specified as a replacement for a compound leg exercise. It does not load the posterior chain, it does not develop hip-extension strength, and it does not produce the systemic training effect of a squat. For those requirements, a different category of equipment is needed.

Frequently Asked Questions

What movement does the GM45 perform?

The GM45 is a seated leg extension. It isolates the quadriceps through knee extension while the torso remains supported by a backrest. It trains the quadriceps independently of the spine and does not load the posterior chain.

What is the weight-stack specification?

The specification sheet does not state the stack weight, the increment value, or the plate count. These should be requested in writing before quotation. A standard commercial leg-extension stack ranges from 60 kg to 100 kg with increment values of 2.5 kg, 5 kg, or 10 kg.

What are the assembled dimensions?

The assembled dimensions are 1242 × 1205 × 1296 mm, giving a footprint of 1.50 square metres. The height of 129.6 cm clears standard ceiling heights and allows the machine to be placed beneath overhead rigging in most facilities.

Is the GM45 selectorised or plate-loaded?

The GM45 is selectorised, with a weight stack and selector pin. The stack specification is not listed and should be confirmed in writing before ordering.

Can the GM45 be used for rehabilitation?

Yes, within the correct parameters. The selectorised system allows load to be increased in small increments without plate handling, and the seated position removes axial loading from the spine. The adjustment range and the backrest angle should be confirmed with the factory before use in a clinical setting.

How much clearance is required around the machine?

The machine footprint is 1.50 square metres, but the working zone should allow 0.60–0.90 metres on the stack side and 0.60–0.90 metres on the entry side. This gives a required zone of approximately 2.40–3.00 × 2.40–3.00 metres.

Does the stack weight equal the resistance felt at the leg pad?

Not necessarily. A lever system changes the mechanical advantage through the range of motion, so the selected stack weight may not equal the force applied to the leg pad. Buyers should request the effective resistance curve before specifying the machine for rehabilitation use.

What warranty applies to the GM45?

The specification sheet does not state warranty terms. Buyers should request separate terms for the frame, the upholstery, and the components, as these carry different expected service lives.

Closing Note

The GM45 is a single-purpose machine, and that is its value. It performs one movement — seated knee extension — and it performs it in a selectorised format that requires no plate handling and no coaching beyond the initial instruction. At 1242 × 1205 × 1296 mm, it occupies 1.50 square metres and shares the same footprint as the GM44, which makes the two machines a matched pair for a leg-training line.

Those facts define the specification. The machine is correctly placed in commercial gyms, rehabilitation centres, and studios. It is not a substitute for compound training, and the stack weight, increment value, and adjustment range must be confirmed before the order is placed.

Quick Spec Recap