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).
http://wiki.answers.com/Q/Why_does_your_side_hurt_after_running_for_a_period_of_time. Pain in the side while running or jogging is called a 'stitch'. It can happen even to the most seasoned of joggers every once in a while.It means the oblique muscle on your ribcage is not getting enough oxygen and is producing lactic acid,...t means the oblique muscle on your ribcage is not getting enough oxygen and is producing lactic acid,..MORE [ Source: http://www.chacha.com/question/why-does-your-side-hurt-when-running ].