Human exercise

How effective is sprin" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">int-in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">interval train" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">inin" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">ing, compared to traditional endurance train" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">inin" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">ing, at producin" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">ing aerobic adaptations in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in" rel="nofollow">in skeletal muscle?