Chapter 2: Anatomy & biomechanics basics for runners

One of the key themes of Running Technique is to explain how the body moves during running.  The images and video on this page are provided as an additional resources to Chapter 2.  Examining these images and the text in the book will also help us arrive at a common set of language and understanding that will make reading the book more informative.

Hip flexion and extension images

When the hip is flexed the thigh is ahead of the body, as the runner pushes off the ground and the leg travels behind the body the hip is extended.

As running becomes faster the degree of hip flex increases.  The runners above and below are elite 1500m competitors so the degree of hip flexion is higher than that of regular runners.

High degree of hip flexion

Again, below we can see am elite 800m runner with a relatively high degree of hip flexion during forward-swing.

As I indicated, regular runners don’t get quite the same degree of hip flex as the elite.  This is me below running a few 400s at more modest speeds.

During top level sprinting the degree of hip flexion can get close to 90 degrees as we can see evident in the runner in red below.

Hip abduction and external rotation

One very important aspect of good running technique is to be able to run with your thighs under the hips.  Here’s me having a go at engaging my buttock muscles to abduct (take away) and slightly externally rotate my hip.  Not too bad, but standing and running with this type of posture is not as easy as you might think!

Below we see an elite 5000m runner maintaining good hip posture even in the late phase of contact.  You will notice the thigh is held very well under the hip.

Knee flexion and extension

Maintaining good knee flexion (bend) at critical phases of the running cycle is one of the key aspects of running well.  Below we can see an elite 1500m runner (center) with good knee flexion as she first contacts the ground.

On the flip side not letting your knee completely straighten is definitely something to aim for – especially during slower running.  Below is a picture of the 800m WR holder.  The image is a good one as is shows even at very high speeds complete straightening of the knee isn’t necessary.

Of course you don’t need to be a world record holder to run with reasonable technique.  Here I am doing a serviceable job of maintaining knee flexion (bend) during contact.

Ankle and foot posture

Getting a handle on runner-speak about the foot and ankle is a good idea.  These days with so much talk about forefoot, midfoot and heel-toe running and the pros and cons of each, you need some level of knowledge to make sense of the commentary.

In the image below we can see my foot and ankle is held in dorsiflexion – the toes and foot are pointed up.  A runner that contacts the ground heel first is therefore running with a dorsiflexed ankle and foot.

This runner below is in the preparation phase and we can see his foot is currently held in moderate dorsiflexion.  Although this changes as his foot ultimately contacts the ground with relatively neutral posture.

The image below shows my foot and ankle in the opposite posture – plantaflexion.  The foot and toes are pointed down.  A runner that contacts the ground forefoot first has their foot in moderate plataflexion.

Here’s an example of a runner with their foot held plantaflexed prior to contact (to be added)

Lower back and pelvis posture/movement

Posture and movement about the back and pelvis is not often discussed in relation to running.  Further into the book I’ll discuss its importance.  In the photo below we can see my pelvis is tilted forwards but my back is held extended (straight).  In good running you need to maintain good upright posture of the back even though your hips and knees are flexed.


You can’t get away from needing a bit of knowledge about the muscles that drive running mechanics.  Throughout my research for the book, everything just kept coming back to activating the right muscles at the right time as being key to good running technique and especially avoiding injury.

The image and discussion below gives you a quick overview of the main muscles involved in running.

Hip extensors: muscles that push the thigh/leg back towards and behind the body (Glutes and Hamstrings).

Knee flexors: muscles that raise the heel towards the butt – they also add force and spring to the hip extension action (Hamstrings).

Hip flexors: muscles that return the thigh/leg from behind the body back to ahead of the body with every stride (Rectus femoris, Iliacus, Psoas).

Plantaflexors: muscles that point the foot and toes down and importantly in running maintain a stiff and springy platform through the foot (Calves, Soleus, Tibialis posterior and other deep compartment muscles)

2 Responses to “Chapter 2: Anatomy & biomechanics basics for runners”

  1. basicbare says:

    I’ve just begun reading your ebook, Brian, and am finding it very interesting. This supplementary information is a huge help. Many thanks for all this good stuff!

    Alan T.


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Joint movement