upping the ante: run farther, run faster, run uphill. If you don’t keep pushing and pushing and pushing some more, the body will settle into homeostasis, albeit at a different level than before, and you will stop improving. This explains the importance of staying just outside your comfort zone: you need to continually push to keep the body’s compensatory changes coming, but if you push too far outside your comfort zone, you risk injuring yourself and actually setting yourself back. This, at least, is
