He burned out because he jumped full on into workouts with one of the top long course triathletes in the world, who is also known for overdoing it. The blind leading the blind. Sanders is now following the Norwegian model and claims that his volume has gone way up, with more intensity at threshold. If Sanders hired him as a training partner, it would make sense to bring him along slowly and check him from himself. It looked like a disaster waiting to happen and it delivered as predicted.