Energy balance also has to do with whatâs going on in your cells. When youâre in a positive energy balance (more in than out) and when youâre in a negative energy balance (more out than in), everything from your metabolism, to your hormonal balance, to your mood is impacted.
Muscle injuries are very common in both professional and recreational athletes. They typically occur in muscles that cross two joints, during explosive activities such as sprinting, and when the athlete is suddenly increasing their exercise regimen (i.e., training camp).
If you run for a long time, you are training the third energy system (endurance system) and will improve your ability to run for quite a while. If you do short, intense sprints, you are training the first energy system (speed system) and therefore improving your ability to be explosive and run fast.