Question

answers to each key question. underline any words you do not understand. reading tool make connections when sprinting, the cells in your legs need more atp to power the rapid muscle movements. ✓ what substance builds up in the muscles, which can cause a burning feeling?

Explanation:

When sprinting, muscle cells use ATP for rapid movement. If oxygen is limited (anaerobic respiration), lactic acid is produced. Lactic acid buildup in muscles causes the burning feeling.

Answer:

Lactic acid