Sometimes it's because you have slept with the arm or leg in a weird position, one that the muscles are not used to being in.. Another possible cause is bad circulation due to blood pressure, or things like smoking.
there are many answers to this perhaps first you should check your blood pressure
Your legs ache at night because during the day your leg muscles have been put to work allot
Walking down-hill, especially with a heavy pack, puts a very high strain on your legs.
Dehydration.
No. Actually, the elephant is the only animal with four knees.
legs'
They have 2 knees, each with one patella. So they have 2 patellas, not four. These are located on their hind legs. Their front legs have elbows, not knees.
They're not really called knees, but yes, they are on the front legs, they bend like our knees, and the back legs bend like our elbows. :) hope i helped
African American's knees are black to match the skin on their thighs and lower legs much like the knees of European American's, having white knees that also match the skin of their legs.
Penguins appear to have very short legs and no knees because only the lower leg is externally visible. Their knees and upper legs are feather covered.
I've only found one so far and its the hypural joint which can be found between the caudal fin of the fish and the last of its vertebrae.
The knee joint.
No they dont have legs