Dead leg syndrome as known by this name in uk & common wealth countries is also known as restless leg syndrome.There is abnormal heaviness feeling in the leg with urge to move them with an abnormal feeling.
There are various causes for this problem-
2.Problem with bones & joint(arthritis of spine joints,pinching of nerve due to neural foraminal stenosis)
3.Decreased calcium intake or increased salt intake.
4.Deficiency of vitamin B12.
& smoking & alcohol.
6.Some drugs like antacids,calcium channel blockers used to treat the high blood pressure,anti depressant & anti psychotic drugs.
To relieve this problem you should do following-
1.Take sufficient amount of magnesium,calcium & vit.B12 in your diet.
2.Avoid heavy intake of salt avoiding salt at dinner is a good solution.
3.Do some stretching exercises.
4.Do some mentally challenging work.
There is association between the osteoporosis decreased calcium level of body & restless leg syndrome you may see following article in support-
I think this will be helpful for you.