Work/rest intervals ratchet up workouts

NEW YORK (Reuters Life!) - If your cardio routine is in the doldrums, try mixing a little tortoise in with that hare.
NEW YORK - United States - Metro Areas - New York City Metro - Business and Economy

Source: http://www.msnbc.msn.com/id/38722170/ns/technology_and_science-tech_and_gadgets/

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