Foot analysis for runners

It is of extreme importance to have comfortable and ergonomic shoes if you are a city runner. I recently went to the Asics store in Amsterdam in order to buy a pair of running shoes. They offered me a free foot analysis before buying my runners, which I enjoyed very much. They have really good knowledge of gait analysis, especially when it has to do with city runners.

I am pointing out the major parts of the manual they gave me after my foot analysis and I add some of my knowledge in order to give you useful information on this matter:

1. Foot length

The length of your foot is measured from the end of your heel to the end of your longest toe, along an imaginary line running from the center of your heel to the end of your longest toe. For sport shoes, you should choose a size approximately 8-10 mm larger than your base foot length. This is because your feet become slightly longer in the propulsion phase o the gait cycle.

2. Ball girth (or circumference)

"Ball girth" measures around the foot, from the ball of the big toe to the ball of the little toe. Ball girth is different from foot width, which is a simple two-dimensional measurement. It is a very important measure for correct shoe fitting.

3. Heel breadth

Heel breadth is measured from the inside to the outside of the hell, at 18% of the distance of the whole foot, measuring from the back of the heel. If your heel is very narrow, you will have to place it more firmly into the heel of your shoes by tightening your laces a little more. If your heel is wide, there is no problem.

4. Instep height

Because it is related to the ball girth, instep height has a subtle effect on fitting. The place to measure the instep is roughly equal to three fingers from the base of the ankle. For example, a narrow ball girth and a high instep may not fit slim shoes.

5. Arch height

Arch height is measured by the height of the navicular bone and is directly linked to the type of arch and instep height. If your feet have low arches and your footprint shows dropped arches, you may have flat feet. Losing the basic shape of arch tends to cause more tiredness and pain.

6. Heel angle

The hell angle is the angle between the vertical line that passes through the heel and the vertical line that passes through your body center of gravity. There are two possibilities regarding the heel angle: pronation (eversion) or supination (inversion). The average is 1.5 degrees of eversion. Excessive eversion increases loading on the inner side of the foot and tiredness around the big toe. Excessive inversion increases loading on the outside of the foot decreasing stability and flexibility.

7. Toe angle

Toe angle shows the inclination of your big toe. In pathologies, it can be either valgus (outward point of the big toe) or varus (inward pointing of the big toe). Both cases have negative effects on your gait.

8. Footprints

There are two main archs in your foot, the transverse and the longitundinal arch. Depending on their height, three deformities can be distinguished:

a. Increased height of the longitundinal arch (pes cavus) - runners with high arched foot choose shoes in the under-pronator to neutral categories.

b. Loss of the longitundinal arch (flatfoot, or pes planus) - runners with flat feet should select shoes in the overpronator to severe over-pronator categories

c. Loss of the transverse arch (splayfoot, or pes tranversoplanus) - same as flatfoot runners

9. Running styles

Depending on the degree of pronation (outward movement of the foot) during running, you can be categorized in one of the three major running styles (the picture above show the right foot from behind):

a. Overpronation

 - excessive outward movement of the foot

 - more load is put on the inside part of the foot, which is transferred to the knee, hip and lower back

 - waste of energy and early fatigue

 - higher risk of injury

b. Neutral

 - balanced gait

 - efficient sock absoprtion

 - more biomechanically efficient

 - low risk of injury

c. Underpronation (or supination)

 - excessive inward movement of the foot

 - more load is put on the outside of the foot, which is transferred to the knee, hip and lower back

 - high foot arch

 - rigid foot

 - high risk of injury but very rare case