Lifting the lid on our legs: What happens when we run?


When you first start running, you use muscles in a very different way to normal. And they WILL let you know about it – anyone who has done a tough workout and then can’t to sit down without groaning will recognise DOMS (delayed onset muscle soreness).



This is for beginners. And intermediates. And advanced runners.  


Some of the gals in the running club I lead are experiencing this. They are all pole dancers – and so their upper bodies are strong as you like. But pole focuses on upper body and core, where as running is almost all lower body and core, and they’re conditioning themselves to a new sport.


So what actually happens in our legs when we run? Whyyyy are we struck down with such pain when all we want to do is run with friends? Haven’t we evolved to do this?


Here’s what has to work each time we take one step in a run:

  • Ankles: When we run, our ankles and feet absorb the impact when we land each time, and also controls the push off into the next step. When we push off, the ankle extends to plantar flexion (when the foot is 90 degrees from the shin). It’s also connected to the Achilles tendon, which in turn connected to the calf muscles.
  • Calf muscles: The calf has two parts: the gastrocnemius, which is what we can see on our legs (also called outer calf), and the soleus, which is a smaller, flatter muscle sitting under the gastrocnemius (inner calf).  The calf muscles lift the heel each step, and extends when we land to absorb impact like the ankle.


  • Shins: These support our arch, raise our toes each time we lift the foot, and absorb impact.
  • Quads: These are at the front of the thigh, and work to extend/straighten your knee and bend the hip each time we take a step. The quad also stabilises the knee and – you’ve guessed it – absorbs impact when we land.
  • Hamstrings: Our hammies are at the back of our thighs, and work to the opposite of the quads: the hamstrings straighten our hips and bend our knees to pull the foot up off the ground each step. The quads and the hamstrings remind me of those huge piston things in the film Titanic that power the boat along.
  • Glutes: As we push off the ground, our back leg extends, which strengthens the gluteal muscles (our butt muscles), which are connected to our hips. The glutes extend the hip as we extend the leg behind, and the bigger the hip extension, the more our glutes need to work. They also stabilise our upper body so we don’t slump over like melting plasticine, which is not good running form. Kim Kardashian’s glutes are doing a real good job.
  • Hips: Our good old hips pretty much influence all aspects of running. The hip flexors (including adductor and abductors) work with the quad muscles to move the leg forward and straighten the knee as we plant the foot down. The hip extensors are the glutes, which as we know work with the hamstring to lift the leg and eventually allows us to bring our legs forward. The hip rotator stabilises the hip joint, and generally the hips stop our knees from turning inwards or outwards.

Hip Flexor

The Hip Flexor Muscles


That’s an awful lot of work to simply lift your foot and plant it down. When you add speed and distance to the mix, you can see why your legs might protest.

Next post I’ll look at some stretches which can help with each of these muscles. I’ll split this over two posts so I can do some more research don’t bore you with too much info in one post. Consider this as ‘lifting the lid on our legs’. Part two will be ‘how can I make this better?’


Have a wonderful day, and I hope the sun is shining where you are!


Ellie B

2 thoughts on “Lifting the lid on our legs: What happens when we run?

  1. thank u for this ellie….im starting to realise how important each muscle is andthe role it plays in something i took.soooo much for granted as a kid :)

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