Just found this article in the newspaper:-
"If you’re an exercise freak, warmi- ups are a waste of time. All you need is a pair of hot pants.
Researchers have found you are better off heating your muscles rather than physically limbering up. Muscle power goes up by eight to ten percent for every centigrade rise in temperature. Warming muscles artificially is better than physical exercise because they get hotter without becoming tired, New Scientist magazine reports.
Howeverm, Olympic gold medal winner Linford Christie said: “Before a race, you need to be on the move. But then I’m from the old school”.