This, though, is great cardio. Most of the exercise I do is along a horizontal plane (I mean running, you saucemonkeys) but I am no longer afraid to explore the vertical. Neither is the British public. The popularity of trampolining has soared since 2010. Bouncing away calories in high-intensity, low-impact cardio workouts that exercise your core, improve all-over muscle tone and lift your heart rate, the bottom line is that trampolining is fun. More than 140 trampoline parks have opened in the UK in the past two years alone. The centre I’m at, Oxygen, has helped more than 950,000 people take up trampolining — with its Acton centre welcoming more than 360,000, making it the most popular centre in the UK (they have another new place in Croydon).