The leg extension machine, also known as the front leg machine, is a specialized device designed to strengthen the quadriceps muscles. Training with this machine is considered an open-chain exercise, as it engages the lower leg and feet in the air.
The seated leg extension machine is designed to create pressure on the thigh muscle, with its movement mechanism being a single-joint (isolated) movement. The dimensions of the device are 140 cm in length and 130 cm in width. As the name suggests, the machine is used to strengthen the leg muscles, specifically the quadriceps.
The leg extension exercise with the machine can be performed in different ways. One of the key factors in performing the leg extension exercise is the position of the hip joint. Activities in resistance training are typically categorized into two types: single-joint and multi-joint exercises. A single-joint movement like knee extension is used for strengthening the quadriceps muscles during resistance exercises. Even though knee extension is a single-joint activity, it also activates the multi-joint rectus femoris muscle (a part of the quadriceps).
The force transfer between the skeletal muscle and surrounding tissues, as well as the length of the sarcomere (the relationship between length and force), can determine the potential force production of the muscle. The rectus femoris muscle crosses both the hip and knee joints. Therefore, changes in the hip joint position during knee extension theoretically affect the sarcomere length and force transfer in the rectus femoris, which may in turn influence torque production.
Studies have reported varying results regarding increased torque production in the hip extended position (lying down) compared to the flexed hip position (seated). The amount of work done by the muscle (exercise volume) and muscle fatigue during the workout are also important factors affecting muscle strength and hypertrophy. Another key factor for hypertrophy from resistance training is muscle swelling, which increases intracellular pressure, triggering anabolic signaling responses inside the cell and thus strengthening the muscle fibers. In this context, the rectus femoris muscle may experience varying pressure (stress) when stretching the quadriceps in different hip positions.
First, select an appropriate weight, then sit on the machine so that your feet are placed under the pad, and hold the side bars with your hands.
Before starting the exercise, make sure the pad is positioned to rest on the top of your ankles, and that your thighs form a 90-degree angle with your lower legs. If this angle is less than 90 degrees, it may place undue stress on your knee joint.
To perform the exercise, keep your legs as straight as possible and, while inhaling, hold the contracted position for one second. Then, slowly return the weight to the starting position.
This variation of the exercise is done to increase focus on one muscle at a time and is recommended for individuals who have asymmetrical thighs.
If you regularly go to the gym, consider the following points:
Use the leg extension machine for 3 sets with 8-12 repetitions and an appropriate weight. Make sure to rest for a few minutes between sets.
Use the machine only after warming up your body (you can use a treadmill, stationary bike, or spinning to warm up).
Warming up on the treadmill is essential before using the leg extension machine. If you cannot go to the gym for any reason but still want to do this exercise, you can simulate it with a resistance band or ankle weights.
When using the leg extension machine, the quadriceps muscles, or the "teardrop" muscles (including the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius), contract the most. The anterior tibialis (calf and hamstring muscles) and the gluteus (buttocks) are also somewhat engaged.
To stretch the rectus femoris and involve the quadriceps more: Adjust the machine so that your knees are on the edge of the seat, and your thighs are completely under the lower pad. Lean your upper body slightly back, ensuring your glutes are in contact with the backrest.
Foot Positioning:
In this exercise, the space between your legs is limited due to the positioning of the machine's pad. If your feet are close together, the outer part of the quadriceps will contract more. If your feet are wider apart, the focus of the exercise will shift slightly to the inner quadriceps.
How to position your feet:
Point your toes upward, which will engage all of the quadriceps muscles.
Point your toes outward, focusing on the outer part of the quadriceps and the vastus lateralis.
Point your toes inward, which will place more pressure on the inner quadriceps and vastus medialis.
The arc formed during the leg extension movement should ideally be 90 degrees. When the knees straighten, the quadriceps are under maximum pressure. To avoid excessive strain on your kneecap, do not bend your knees more than 90 degrees.
Here are some reasons why this exercise is important:
When using the leg extension machine, testosterone levels rise, which is essential for muscle building. As a result, you promote the growth of all your muscles.
Experienced athletes have shown that those who neglect leg exercises will eventually lose balance between their upper and lower bodies, leading to poor body proportions.
Strong legs are the foundation for performing upper-body exercises. Without strong legs, many upper-body exercises will become challenging.
As people age and enter middle age, leg muscles tend to weaken. To maintain leg health and youthfulness, you should incorporate lower body exercises alongside upper-body training. Additionally, strengthening the quadriceps can help relieve pressure on the joints.
Overdoing cardio: Cardio exercises increase heart rate and breathing, improving cardiovascular health. However, excessive cardio can burn too many calories and deplete the nutrients your body needs. If your body experiences a calorie deficit, it will begin to break down muscles to produce energy (a process called catabolism).
Not changing your workout routine over time: If you focus on a few exercises, your body will adapt, and muscle growth will plateau. Changing your routine regularly is important to avoid mental burnout and stagnation in your physical progress.
Overtraining
Inadequate rest
Applying too much pressure to one specific part of the body
