I have said this from day one—when you have a choice, run outside on grass, sand, etc. (not pavement, asphalt or other hard surface)…..Why? Because its tougher—you have to supply all the momentum and force with no help from machines!
Well, research says that you will burn 10% more calories by running on the ground (its really common sense!)…..I believe its probably more when you figure in wind resistance and natural land inclines…..
Get the most fat-burn and calorie-burn from your workouts—do your cardio workouts outside! Running outside is definitely my first choice and sprint intervals (20 minutes in some form) is the cardio workout I do the most. It works—much better than cardio on machines!
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