The quadriceps muscle plays a vital role in knee and hip joint flexion.

In the human body, multiple structures are responsible for supporting others and creating movements; among them, the muscles, bones, fascia, tendons, and ligaments stand out. For example, in the case of the muscle tissues of each lower limb, the quadriceps, hamstrings, peroneal muscles, and the triceps surae are located.

The quadriceps are subdivided into four bellies or vastus: the vastus medialis, the vastus lateralis, the vastus medialis, and the rectus femoris.

All of them are knee extensors, but only the rectus femoris flexes the hip because it is biarticular. In other words, the quadriceps are fully trained in a knee extension.

muscle regions

over the knee

The different quadriceps vastus work similarly on the knee. They have a more incredible lever arm between 0-45º of flexion and slightly lose their action with the knee fully flexed, each of their regions behaving similarly. This makes it difficult to target one vastus to a greater extent over the other through greater or lesser knee flexion.

on the hip

The rectus femoris is the only vastus of the quadriceps with implications on the hip. This means you can flex the hip and the TFL, sartorius, psoas major, iliacus, adductor brevis longus, and pectineus. Still, depending on the movement, one or the other will participate to a greater or lesser extent. In the case of the rectus femoris, its most excellent leverage arm is with the hip fully extended. That is why, to maximize its Muscle Growth, it benefits from exercises with knee flexion-extension but with the hip extended or with reduced ranges of flexion and origin without movement.

The quadriceps, an essential muscle group for moving

Since the origin of our existence, the quadriceps has helped us move. First, on all fours, continue standing, fulfilling the same function: Flex the hip by bringing the thigh closer to the trunk and extending the knee. This makes the quadriceps one of the most important muscle groups in the body to function daily.

It is essential to have an independent life when walking, climbing stairs, jumping, running or sitting, and getting up from a chair. But in these and more tasks, the quadriceps are not alone; they are rare muscle groups complementing it. Mainly with the hamstring muscles, which extend the hip, bring the leg backward (mainly with the knee stretched), and flex the knee. For example, when sitting in a chair, the quadriceps will help flex the hip while the hamstrings will assist in controlling the movement.

That is, they allow themselves to be overcome gradually in an eccentric way, stretching with control. We call this type of muscle relationship Agonist.

How is the quadriceps formed?

This muscle is called that way because it is composed of 4 heads, which have their origin in similar places in the leg, but in the case of insertion, they share the same place in the kneecap, so tissue is formed. Single called quadriceps tendon.

That is why they are described separately below:

• Vastus intermedius or crural: originates from the external and internal edge of the femur.
• Vastus lateralis: has its origin in the linea aspera of the femur.
• Vastus medialis originates from the femur’s linea aspera but in the inner lip region. 
• The rectus anterior or femoris is the only one originating in the iliac bone, at the level of the anterior-inferior iliac spine and the cotyloid eyebrow.

Benefits of quadriceps extension

Improves sports performance

Strengthening the quadriceps helps increase power when running and jumping and serves as a support muscle for the glutes, back, and knees.

Burn calories

As with any exercise, quadriceps extensions help burn calories. But, since this exercise involves a muscle group of four muscles, it will slightly increase your calorie burn compared to other exercises.

Combining compound exercises with some isolation exercises is essential for a leg routine to be complete and adequate. A compound exercise involves several joints and several muscle groups; an isolation exercise involves only one joint and very few muscle groups.

Squats

Squats are effective quadriceps exercises. In any of its modalities, they will help improve the performance of this muscle and your lower joints. It would help if you first separated your feet to put them at shoulder height to do them correctly. Secondly, leave your abs tense and lean your torso forward a little to obtain greater activation in the quadriceps area.

It is essential to place your hands in front of you to gain stability in the movement. Finally, we will lower our hips until they align entirely with our knees. It is not advisable to go below that height. We will return to the starting position using force with the balls of our feet to activate our quadriceps more.