Bodybuilding Anatomy – Quadriceps Femoris
The legs consist of three primary muscle groups. The largest is the four-headed quadriceps that runs from the pelvis to the knee. The muscle is so named because it has four heads, just as the biceps has two heads.
In bodybuilding, the words massively carved, ripped, chiseled, and separated describe the perfect pair of thighs. As the foundation of human muscularity, the thighs are clearly the most powerful muscles of the physique.
What are the Quadriceps Muscles?
The quadriceps is a group of four muscles on the anterior (front) of the thigh. The four muscles are the vastus medialis, vastus intermedius, vastus lateralis, and rectus femoris. The first three attach to the front of the tibia and originate at the top of the femur. The rectus femoris crosses the hip joint and originates on the pelvis.
The RECTUS FEMORIS is a hip flexor as well as part of the quadriceps group. The rectus femoris is easy to see on a lean person; it is the middle quad among the three that you can see, and it sits right on the top of the femur. Among the quads, it is unique in that it is a two-joint muscle, crossing both the hip and the knee joint. It’s the muscle that splits down the middle of the thigh, originating at the pelvis and ending, along with the other three quad muscles, in the quadriceps tendon, which crosses the kneecap and attaches to the tibia, the larger of your lower-leg bones. The VASTUS LATERALIS is the big muscle on the outside front of your thigh. It originates on the outside top of the femur. If you slap the outside of your thighs, you will hit this muscle. In the gym this part of the quad is called the sweep because a well-developed lateralis goes up and out from the knee and can add significant size to the overall quad. Any exercise that involves straightening the leg against resistance works the quads and, therefore, the vastus lateralis. But to emphasize the lateralis during those exercises, you want to keep your toes straight ahead and keep your feet relatively close together, narrower than shoulder-width. Doing this is hard with a free-weight squat, but it is easy to do using the hack squat, leg press, and Smith machine. In addition, the lateralis receives more stimuli the lower you go in a squatting motion, so make sure to go all the way down to emphasize this muscle. The VASTUS MEDIALIS originates on the inside of the femur, with attachment points running most of the way down the bone. The medialis is very thick near the bottom, forming a teardrop shape (starting narrow and then getting wider going down) just above and to the inside of the knee when it’s fully developed. Medialis means “medial”, referring to the part of your thigh that is closest to the midline. Do not confuse your medialis with your adductors, which are much higher up your leg. Beneath the rectus femoris and between the lateralis and medialis is the VASTUS INTERMEDIUS, with origination points all down the front of the femur. This is the smallest of the quads and it is not visible because it’s covered completely by the rectus femoris. The vastus intermedius is the only one of the quads to originate on the front of the femur.
Quadriceps: Origin, Insertion, and Action
| Quadriceps Muscles | Origin | Insertion | Action |
|---|---|---|---|
| RECTUS FEMORIS | Anterior inferior iliac spine (AIIS), lower ilium | Patella to the tibial tuberosity through the patellar ligament | Extends the knee, flexes the hip |
| VASTUS LATERALIS | Linea aspera of the femur (lateral aspect) | Patella to the tibia through the patellar ligament | Extends the knee |
| VASTUS MEDIALIS | Linea aspera of the femur (medial aspect) | Patella to the tibial tuberosity through the patellar ligament | Extends the knee |
| VASTUS INTERMEDIUS | Upper anterior shaft of the femur | Patella to the tibia through the patellar ligament | Extends the knee |
What are the functions of the quadriceps?
The primary function of the quadriceps is to extend (straighten) the knee joint. That movement is fundamental to running and jumping, which is why this muscle group is capable of both tremendous strength and awe-inspiring endurance. The rectus femoris also extends the knee, and because it crosses the hip joint, it flexes the hips.
Other Names
- Front thigh
- Quads
- Upper legs
Quadriceps Exercises
Second only to calves and hamstrings, the quadriceps are one of the most neglected muscle groups, especially by those individuals just starting out in bodybuilding or weight training. This is primarily due to the focus on developing a powerful and big upper body, which often comes at the expense of lower body development. Unfortunately for individuals that take this path, the neglect is eventually easy to spot. Too often, you see people who have huge arms, massive upper bodies—and tiny legs. It looks like they’ve never done a leg exercise in their lives. And that may be the case.
Exercises that work the quadriceps are all movements that require you to straighten the legs against resistance. This includes all varieties of leg presses, squats, and lunges.
To develop a particular muscle in the quadriceps group more than the others, you can turn your feet in different directions during leg exercises or emphasize one part of the range of motion over other parts. To get maximum results with leg exercises, you have to work up to using heavy weight and doing many, many sets. You need the intensity to do a few more reps when you feel like your legs are about to give out.
In general, during compound leg exercises, the deeper you go, the more you emphasize the glutes, and the shallower you go, the more you emphasize the quads.
Because of the weight used and the emphasis placed on the quadriceps muscle, the leg press is an excellent exercise to build up the quads. In everyday activities, the quads work with the glutes to allow people to stand up from a sitting position and to provide power for running and jumping.
Best exercises for the quadriceps:
- Squat (back and front squat)
- Leg press
- Leg extension
- Lunge
- Step-up
- Hack squat
