High-heel wearers have problems walking flatfoot, although it is a well-known fact that it is actually the stiletto that causes painful ankles.
In a study, Marco Narici from Manchester Metropolitan University and Robert Csapo, from the University of Vienna, Austria, compared two groups of women - one regular high-heel wearers and another who didn't.
Csapo and Olivier Seynnes, another researcher, then compared the muscle fibre length in the women's calf muscles.
Narici explains that when you place the muscle in a shorter position, the fibres become shorter.
However, by shortening the fibres, the muscles would have to contract more to shorten by the same length, and if this was the case the high heel fans' calf muscles could no longer function optimally and thus would produce less force than the flat shoe wearer's calf muscles.
Also, the high heel fans' tendons were much thicker and stiffer than the flat shoe wearers.
The Achilles' tendon compensates for the shortened muscle fibres in the calf muscle, allowing the fashion addicts' calf muscles to function optimally as they walk, but causing discomfort when walking on flat feet because the tendon cannot stretch sufficiently.
Narici suggests stretching exercises regularly to avoid the soreness when women kick off their high heels.
The study is published in the Journal of Experimental Biology.