9.4 Basic Lower Body Exercises: Machine-Based
Leg Press
Purpose: Challenges the quadriceps group, the gluteus group, the hamstrings group, and the calves.
Form and movement pattern:
- Movement begins seated with the back and head supported by the backrest, with the feet placed hip-to-shoulder-width apart on the platform.
- Extend legs to press the platform away from the body, avoiding full extension of the knees.
- Lower the platform by bending at the knees and hips until the thighs are approximately 90 degrees to the lower leg.
- Extension and flexion of the knees and hips should be slow and controlled, with a brief pause at the bottom of the movement.
Common mistakes (and how to avoid them):
- Letting knees collapse in or outward reduces proper alignment (keep knees in line with toes; a ball or foam roller squeezed in between the knees can help).
- Allowing the lower back or hips to lift off the backrest can increase strain on the lumbar spine (keep core engaged and avoid excessive knee flexion).
- Locking the knees at full extension places the load on the joint rather than the working muscle (maintain a slight bend at the top of the movement).
Modification & equipment:
- Foot placement can alter muscle emphasis (e.g., higher foot placement engages the glute and hamstring groups more, whereas lower placement emphasizes the quadricep group).
- Single-leg press can address muscle imbalance.
- Weight and ROM can be adjusted to suit individual needs.
Leg Extension
Purpose: Isolates and challenges the quadricep group (i.e., rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius).
Form and movement pattern:
- Movement begins seated in the machine with the back against the backrest, knees aligned with the machine’s pivot point, and shins under the padded bar.
- Extend knees by contracting the quadriceps group to lift the padded bar upward.
- At the top, pause briefly before slowly lowering the bar back to the starting position.
- Knees should not lock at the top; movement should remain smooth and controlled in both directions.
Common mistakes (and how to avoid them):
- Lifting the hips off the seat pad can increase stress on the lumbar spine (adjust the backrest to the preferred depth and angle, and engage the core).
- Using momentum or swimming, the legs lead to reduced muscle activation (movement should be slow and controlled).
- Locking knees at full extension can strain the joint (stop just short of full extension or ‘lockout’).
- Letting the toes point downward, or plantar flex, disengages some of the quadriceps group muscles (keep toes in a neutral or slightly dorsiflexed position).
Modification & equipment:
- Adjust seat height, angle, and position of all pads (back and/or legs) to assure proper support.
- Weight and ROM can be altered to suit individual needs.
Hamstring Curl
Purpose: Challenges the quadriceps group, the gluteus group, the hamstrings group, and the calves.
Form and movement pattern:
- Movement begins with the thighs firmly supported and the padded bar resting just above the heels (seated or prone).
- Flex the knees by drawing the heels toward the glute group, engaging the hamstrings group.
- Pause briefly at the end of the curl before slowly returning to the starting position.
- Keep hips and upper body stable to prevent compensatory movement.
Common mistakes (and how to avoid them):
- Arching the back or lifting the hips (especially in a prone position) reduces isolation (maintain contact with the pad and engage the core).
- Using momentum or jerking the weight reduced muscle activation and control (slow down both phases of the movement).
- Incomplete ROM reduces effectiveness (ensure the full flexion and extension without locking of the knee joint).
Modification & equipment:
- Adjust the seat height, angle or pads for individual preference.
- Machines may offer seated, prone, or standing variations; choose the one that best suits your control level.
- Single-leg hamstring curls can help address muscle imbalances.
- Resistance bands or ankle weights can also be used to mimic the movement.
