Sources of energy of exercising muscles
First 1 or 2 seconds ---- existing ATP stores
Next 3 to 5 seconds ---- Creatine Phosphate
Within 10 seconds these will be depleted then
Muscle glycogen will break down providing the glucose
This glucose will be metabolized anaerobically by glycolysis to lactic acid
Then gluconeogenesis kicks in when muscle glycogen stores vanishes
Then when gluconeogensis no longer support the glucose needed
Fatty Acid oxidation is the final resource to supply the energy