How Fitness Works: Legs

Do you ever sit around and wonder how something works? I know I do, because I’m a huge nerd that loves to know what makes things “tick”. In 2016 I’m doing a special series called “How Fitness Works”, where I’m going to explore how different things related to health and fitness…well…work! You can find all the articles in this series by searching for article tag HowFitnessWorks on this blog.

Today we’re talking about your legs. How do they work? What makes them go? What’s good for them and what’s bad for them? For this article we’re including everything below (and not including) the hips in our definition of where your legs are.


bones of the leg and footStarting from the top and moving down, your legs are made of three major long bones:

  • Femur (top leg)
  • Tibia (front lower leg)
  • Fibula (back lower leg)

The bone of your knee is the patella, a flat triangular bone that helps stabilize the knee joint.

Your feet are made up of three collections of small bones called:

  • Tarsals
  • Metatarsals
  • Phalanges


There are two main joints in your leg, the knee and the ankle, and there are smaller joints around the toes.

knee jointThe knee is formed at the meeting of the femur and tibia, protected by the kneecap (patella) and is a hinge joint. It only moves through about 160 degrees of range and bending it backwards is a bad thing. Like, super painful kind of bad.

In between the bones of the knee you find cartilage, the same stuff that makes up the pretty part of your nose. This pseudo-bone slightly rigid material is found a lot of places where bones meet to provide cushion and lubrication for movement. There are disorders of the cartilage that can create all kinds of issues for movement, including shooting pain, dull pain, and immobility.

ankle jointYour ankle begins at the end of your tibia/fibula and connects to your foot. No real news there, I’m sure, but keep in mind that the start of your toes is not part of your ankle. Technicalities are fun!

You have a few interestingly shaped bones in your ankle, including:

  • Talus, shaped kind of like pauldrons, the shoulder armor worn by European knights back when swords on horseback was still a big thing. It sits just below your lower leg bones but above your heel and foot bones. It forms the true ankle joint with the lower leg.
  • Calcaneus, which kind of resembles a doorknob. It’s the bone that forms your heel, sitting under your talus and behind the tarsals that begin the foot. There is a subtalar joint that connects this to the talus towards the back of your foot.

foot jointYour foot is too complicated for being as small as it is, but the complication is what allows us to have such great mobility in walking and other foot-related activities (like salsa dancing and win grape stomping).

The joints of your foot are defined by what parts they connect, so the Metatarsophalangeal joint connects your metatarsals and phalanges.

There are also two Interphalangeal joints, with the proximal ones being the first joint of your toes and the distal ones being the second joint in your toes. These are the bits that hurt when you stub your toe.


There are a ton of small muscles in the legs, but today we’re going to talk about the large muscle groups as an ice breaker. We’ll go into painful, nitpicky detail at a later date! The major muscle groups in the leg are:

leg muscles



Quadriceps, also known as the ones that help you do squats from bottom to top. They help move the body from a squatting position to a stand, including jumping.

Tibialis Anterior, also know as the muscles you can never seem to figure out why they hurt but they always seem to during calf raises and heavy deadlifts. They help stabilize your stance and flex the foot.


Glutes, otherwise known as your butt, padonkadonk, and lower cheeks. Contracting your glutes helps assist the squatting motion and other motions that push the hips forward.

Hamstrings, or the back of the leg that most hurts when applied to a foam roller on any given day, helps lower the leg under control as well as straighten the leg when pulling, rather than pushing, weight. For instance, deadlifts are hamstring killers (in a good way). Colloquially know as your “hammies”.

Calves, the back of your lower leg, used to flex your foot to a point and stabilize your squatting motions. They are play a role in controlling and improving your jumps and landing to ensure you don’t fall down and get laughed at. The singular form is “calf”, plural “calves”, because English, that’s why!


And boom! That’s how your legs work, in a nutshell. Join me next time when I nerd out about something that will seem random to you, but makes perfect sense to me!