Lifting a heavy weight to the point of exhaustion causes micro-tears in the muscle’s tissue and triggers the stress response. The body becomes aware that it’s currently not strong enough to tolerate the stress it is under. Consequently, once we cease lifting weights, the body transitions into something called an anabolic state, in which the muscle is built up so it can withstand more stress in the future. This same process unfolds after just about any hard physical effort—from lifting weights to running to rowing to a challenging CrossFit workout.
