Flat feet, and side split training

[Jack123]

Is there anyone here, who has done side split training in spite of having flat feet (partial/complete)?

Condition: I am a 25 year old male, in reasonably good shape, and have been training in martial arts, soccer and sprints for quite a while. I have a partial flat foot (the arch is less than normal) in my left foot. I do foot arch strengthening exercises, but do not expect things to improve to a normal arch. However, I do not have any problems in day-to-day activities, or even in my sports training. Walking barefoot in my house helps

Problem: I have recently started to focus on achieving a side split using Tom Kurz's isometric split training method and have a question. Since the method requires you to press down into the ground from a semi-split, it flattens my foot further. The arch of my right foot is completely normal, and I do not have any problems there. But my left foot begins to pain soon after finishing the exercise.

What should I do? Does anyone else have the same problem?

Thanks,
Jack

[Thomas Kurz]

Exercise in shoes/sneakers with an orthotic insert in the left one. If you must exercise barefoot, tape an arch support to your left foot.