Leg Extension (Machine)
The Leg Extension Machine is a seated isolation exercise that specifically targets the quadriceps muscles on the front of the thigh. By stabilizing the hips and moving only at the knee joint, it allows for focused strengthening and development of the quads without engaging other muscle groups.
Leg extensions allow you to isolate the quadriceps without the systemic fatigue associated with heavy compound lifts. Iridium programs this exercise to bridge the gap between your current workload and your Maximum Adaptive Volume, particularly when your 7-day history indicates your lower back needs a break from axial loading. The system manages progression by analyzing RPE and weight trends to ensure you maintain sufficient intensity even on accessory work.
Form Cues
- Align your knees with the machine's pivot point
- Hold the side handles for stability
- Extend your legs until straight but not locked
- Squeeze your quadriceps hard at the top
- Lower the weight slowly and under control
- Don't let your hips lift off the seat
- Don't kick the weight up using momentum
- Don't lock your knees forcefully at the top
- Don't let the weight stack slam down
- Don't rotate your feet excessively
Common Mistakes
- Misaligned knee pivot point
- Using excessive momentum
- Lifting glutes off the pad
- Shortening the range of motion
- Lowering the weight too fast
Muscles Worked
This exercise is the primary isolation movement for the quadriceps femoris group, targeting the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. It is particularly effective for strengthening the terminal knee extension and placing tension on the rectus femoris in a shortened position.
Primary
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