Weakness in the foot muscles causes the arch of the foot to drop. The problem is not caused by cycling, but rather by our sedentary lifestyle. The immobilisation of the feet in shoes often prevents the necessary training stimulus for the foot muscles. Unlike when running barefoot, the foot therefore has to do less work in shoes. On the bike, this can lead to pain on the inside of the foot. But it can also lead to many other knee or hip problems.
Walk more barefoot, your feet will train themselves. Various manufacturers offer the right footwear for this (e.g. Vivo barefoot). You should also incorporate foot training into your everyday life. How about picking up objects with your toes or standing on one leg while brushing your teeth? If you need more inspiration, you can find it in the book "Feet good, everything good" by Carsten Stark.
A suitable insole can work wonders. Go to an orthopaedist or orthopaedic shoe technician to find the right insoles (ideally an expert with a background in cycling, as cycling or mountain biking requires different strength curves than walking). If you have fallen arches, you will usually receive a supplement from your health insurance provider. In most cases, the right sole will show how the MTB should be further adjusted.
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