Identify this machine
A seated curl bends the knees against a lower leg pad. It differs from the leg press, which pushes a footplate. Ask staff to demonstrate this model, its adjustments and how to get out. Follow its placard rather than copying another machine.
Align the knee and pads
Begin with manageable resistance. In the Life Fitness example, the knee meets the machine pivot and the thigh restraint rests comfortably on the lower thigh. Adjust the seat and lower leg pad as that model instructs. Keep the back supported. Choose another option if it cannot fit comfortably.
Bend without lifting the hips
Hold the intended handles and draw the lower legs down and back slowly. Keep the thighs restrained and hips on the seat. Do not swing the torso or force a deeper bend. The roller resists the back of the lower legs, not a push from the fronts of the shins.
Give the return equal attention
Let the knees open gradually toward the starting position without snapping them straight or dropping the resistance. Reduce the load if you cannot slow the return. Stop for pain or lost control. Mayo Clinic emphasizes technique and getting help with unfamiliar exercises.
Record a repeatable setup
Note the model, seat and pad settings, displayed resistance and controlled repetitions. Different machines need separate records. The equipment comparison explains this distinction. Explore planning in Fitonomy. No fixed load or repetition target is required here; injury, surgery or restrictions need individual advice.
A curl bends the knee with a different roller contact. If you are also learning a machine that straightens the knee, review the leg extension setup separately before choosing its backrest and front shin pad settings.