Is carbon too stiff?

jehannum5 Posts: 54
edited November 2011 in Health, fitness & training
Just after advice or to see of anyone else has gone through this. I have been using shimano carbon soled bike shoes for years with no problems, even riding long long hours with no ill effects. Recently upped my mountain bike riding (I normally ride road and MTB with the main balance spent on my road bike). Riding big hills etc and I have noticed my feet are sore after riding, no hotspots, just generally sore over the entire foot. I've had similar a feeling after long runs, so I'm postulating it's a result from shock transmitted from the trail.
I'm contemplating buying 'lesser' quality shoes ie shimano or sidi with a nylon sole rather than carbonto get more flex. Certainly I rode for years with a shimano nylon soled shoe in the years before carbon soles (yes kiddies there was a time) and never noticed that they were unduly flexy. Is carbon too stiff?