Knee & Leg Extension Exercise Equipment

If you do any type of activity that is repetitive or places stress on the knees--such as running, spinning, hiking or biking--it is important to participate in strength-training exercises for the muscles that surround the knee joint. If you have injuries or have undergone hip or knee surgery, knee and leg extension exercises will be a big part of your treatment program. There are different types of knee and leg extension equipment both made for home use and found in the gym, and it is important to use them correctly to prevent injuries.

Significance

To maintain good joint health, it is essential to strengthen the muscles that surround the knee joint. If your leg muscles are weak or tight, they can pull on the joint and actually cause the kneecap to move out of alignment. The result will be injury and pain. This is especially true for those who participate in sports that place strain on the knee joint due to pounding or repetitive bending. Since the quadriceps muscle in the front top of the thigh is responsible for moving the knee cap, you need to keep this muscle strong to prevent and manage knee injuries. Knee and leg extension machines are a good, low-impact way to target and strengthen this muscle.

Identification

Knee and leg extension equipment are machines that you sit on. You then place your ankles behind pads and push the pads up until your knee is straight. Some models, like those found in gyms, have weight stacks into which you insert a pin to select the weight you want to use. See the picture at the top of this page. In smaller models that are good for home use, you place free weights on a bar, like in the picture shown here. While the machines that work with weight stacks are usually larger and more stable, smaller machines are more adaptable to different body sizes. It is important to try several types and models to see which one fits you best.

Considerations

When you lift weights, there are two motions: the positive and the negative. The positive movement is when you lift the weight, and the negative is when you lower the weight. The benefit of using a leg extension machine over standing free weight exercises like squats and lunges is that the machine provides more stability since you do not have to maintain balance. In addition, it is non-weight bearing. This is important, especially if you are rehabilitating from an injury or when weight-bearing exercises are too painful. Another benefit is that with commercial types of leg extension machines, you can set the machine to limit your range of motion so you do not overbend or hyperextend the knee. This will help you build strength while cutting down on the risk of injury.

Features

To use a knee or leg extension machine correctly, make sure that you can adjust the machine to fit you correctly. Adjust the lower bar so that the pads are against your ankles. They should roll up onto your shins as you lift the weight. If the leg extension machine has a back support, sit all the way back and line up your shoulders over your hips. The seat should easily slide forward so that your knees are just at the end of the seat. If this is not possible, place a cushion behind you to get better back support. On commercial models there is also a pad that rests down on your thighs. Use this pad to stabilize yourself as you lift.

Warning

Knee and leg extension machines provide a safe and effective way to strengthen your quadriceps muscles when used correctly. One common mistake is to hyperextend the knees as you lift. When lifting the weight up, stop before your knee straightens or locks. Lift up until the knee has a slight bend and stop. As you lower, do not overbend the knee much past a 90-degree angle (the ankles will be directly under the knees). With commercial machines, there is a pin you can place in the weight stack to prevent you from overbending. Always use control when lifting weights. Keep your entire back flat against the back support and stay in the seat. The ankle pads should stay in contact with your ankles at all times. Use a slow 2-second count to slowly lift up. Pause for a moment at the top to control the movement. Then use a slow 4-second count to lower back down.