Give your quads the focus they deserve by incorporating this important leg exercise into your lower body workout.
In a world of compound movements, functional training, and total body exercises, the leg extension is sometimes dismissed as a one-trick pony. After all, it's an isolation movement that only affects one muscle group, the quadriceps, and is performed on a machine - as opposed to the squat, which is considered a more masculine barbell movement that involves the entire lower body and has many benefits.
The leg extension is one of the more polarizing exercises. Some people love it and see tremendous value, while others find it a waste of time and others cite quad moves as having more benefit. Either way, the simplicity of leg extensions is also their biggest asset and a solid step in building leg strength.
Benefits of leg lengthening
Leg extensions target the quads, which have gone unnoticed in recent years as the popularity of functional movements and CrossFit routines have stressed the hips and core. But dismissing the quads as aesthetic muscles or "lower-body triceps" neglects a vital part of your body's operating system. That's because the four-pronged quadriceps muscles serve to straighten the knees, making strong quadriceps crucial for walking, running, jumping, and squatting.
The quads play an essential role in stabilizing your knees and helping flex your hips, which get tight after a full day of sitting at a desk or behind the wheel. Strong quads are necessary for movements of everyday life and athletic activity. Few moves work the quads better than the leg extension.
What does the leg extension work?
For leg extensions, focus only on the quads: vastus medialis, vastus lateralis, vastus intermedius, and rectus femoris. The rectus femoris is the most commonly injured quadriceps muscle when exercising, in part because it flexes the thigh at the hip and straightens the leg at the knee joint.
This muscle, like the rest of the quadriceps, deserves special attention. Few moves give you more immediate visual feedback than leg extensions, as you can see the quads flex and contract as you raise and lower the padded bar.
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How to do leg extensions
- When you shift weight on a leg extension machine, you fight the urge to load it, especially at first with heavy resistance. Better focus on proper form and really feel it in your quads.
- Sit in the leg extension machine. Depending on the height of the last person using the device, you may need to adjust the seat cushion forwards or backwards. Position your legs under the pad and grasp the splints with your hands. Adjust the shin guard so that it is just above your ankles.
- Extend your legs as far as possible while exhaling. While this is an easy move, make the most of it and avoid injury by taking it slow and avoiding fast movements that can increase the risk of hyperextending your knees.
- Hold this contracted position for two seconds, increasing the time under tension without locking the knees at full extension.
- On an inhale, lower the weight back to the starting position. Remember slow. Don't just drop back to the starting position or bring your legs past a 90-degree position.
How to add a leg extension to a workout
As an isolation exercise for the quadriceps, leg extensions are an important part of leg days and can be performed after compound movements like deadlifts or squats. Some people like to start with leg extensions. Others prefer to save them for last to get that final leg burn on a lower body workout.
Leg Extension Variations
Unlike other movements, there is little variation in leg extension other than adding or removing weight. If you're anywhere without leg extensions, you can improvise with any exercise that requires you to contract your quads against a resistance that creates the same effect. If you are at home or traveling, sit in a chair and use ankle weights or resistance bands.
