Popsugar Fitness Workouts Cardio Workouts For the Gym: Treadmill Too Hot to Run Outside? Here Are 7 Treadmill Workouts to Take to Gym July 31, 2018 by Susi May View On One Page Photo 4 of 7 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 4 20-Minute Workout Click here for a printable PDF of this 20-minute workout. Previous Next Start Slideshow WorkoutsTreadmill WorkoutsPrintable Workouts