<span>Alternating between running and walking is important, especially if you're not a professional runner. You should be walking from time to time to recover a bit from the strain that the running put on you, but not too much or your body starts to cool down and then you have to work all over again or you might lose energy.</span>
What doesn't limit the range of moton from the things which you've mentioned would be age. Age per se doesn't really limit the range of motion - while there are factors which negatively influence our range of motion and which are strongly correlated with age, it is hard to say that age itself would be the cause of a limited range of motion.
<span>Protein is underconsumed in the United States. The people in this country do not eat more on protein because of being health conscious. They eat bread instead of rice and cereals in the morning but they lessen their protein. They eat vegetables and fruits more than proteins in order for their body to get more energy and vitamins.</span>
C. H<span>ow hard a person works to do an activity.
Intensity has to do with effort. If a person works hard than they are intense, if vise versa than they are not intense.</span>