How Slowtwitch Fibers Adapt

From Slowtwitch

I have wondered for some time about an aspect of muscular recovery. When we do resistance exercise, our muscles get sore then rebuild and become larger, a process called hypertrophy. Since slowtwitch muscles have less potential for growth in size compared to fast twitch, many experienced endurance athletes (ie marathon runners) have achieved close to their maximal slowtwitch hypertrophy. My question was this: if our slowtwitch muscles get sore after a long run, then repair and are less sore after the next long run, what adaptation is taking place to decrease the soreness if it isn't hypertrophy? Here is the explanation I received that was later supported by a friend that is an Exercise Physiologist.

"(This adaptation) is well acknowledged in the scientific world and attributed to some adaptive response that appears to attenuate the inflammatory response, hence reducing the secondary injury....The nature of the adaptive response is still unclear, but happens within a couple weeks after the initial novel exercise, and lasts for quite a while."

So, the body develops a tolerance to the stress hormones that are released as a result of the long run resulting in less soreness. Another factor that fits in to this topic is the fact that the training will increase the muscular efficiency meaning glycogen is spared, more fat burned, and less catabolic damage to the tissue.