Fitness training is simply a system of checks and balances. Just like the rest of your life. If you put in a hard workout, you need to replenish your system with good, wholesome food. You did a whole days worth of work after your workout? This may require up to 9-10 hrs of sleep to let your body properly recover. If you lift weights often and stress your muscles, make sure you’re taking care of them by getting massages (or self massage with a foam roller), stretching often, and warming up and cooling down properly. For me, this also involves my weekly visit to my chiropractor. It’s important for my spine and joints to be aligned properly before I throw a bunch of weight on it week after week. Life knocks us out of alignment with routine events, so make sure you’re back on track before you expect your body to deliver for you!