with proper form you can.
oxygen
Skeletal Muscles
When you exercise you use your muscles and your muscles contain Glycogen which could be considered your "energy source". during exercise your muscles use glycogen depleting your energy levels making you feel tired.
Trunk curls are the only exercise which effectively isolate the abdominal muscles. All other abdominal muscles - e.g. sit ups, leg raises, etc. - primarily work the iliopsoas muscles of the hips, not the abdominals.
lactate
Type of fermentation that occurs in muscles during rapid exercise? Answer: lactic acid fermentation
i wish the world had a brain....
>95%
To your muscles which you are using.
Because the heart beats faster during exercise to ensure that oxygen gets to the working muscles.
Skeletal muscles can be consciously controlled during exercise, whereas cardiac and smooth muscles cannot be consciously controlled.
Muscles contract and relax to move a joint.