Question

After several miles of running and sprinting in intervals, the runner’s muscles ache and feel fatigued. Which is the best explanation for what has occurred?

Answer 1

Lactic acid build up most likely. Lactic acid builds up in the body and causes the sore and achy feeling when exerting ones muscles. Lactic acid builds when oxygen is not getting to the muscles fast enough. I hope this helps.

Answer 2

A build up a lactic acid in the muscles causes the pain and aching soreness.