Many fitness tests include speed and agility in addition to endurance runs. You need a good workout to take to the track to ...

When you're running up stairs or out on a jog, your muscles eventually start to feel heavy and weak. That's fatigue setting in, a sign that the muscles' energy reserves are becoming depleted. But a ...

Julia Ries Wexler is a writer focusing on all things health and wellness. She has over 10 years of experience in health journalism, and though she has written about pretty much every health topic ...