Rugby’s got 40 minute halves, with no stoppages in play — except in between scoring and kickoff, which amounts to about 30 seconds. You have to run, break tackles, pass, tackle, ruck, scrum down, and lift/jump for line-outs.
Not only are they balancing on a surfboard, but windsurfers also have to grapple with unpredictable winds and the heft of the sail.
Fighting altitude, fatigue and gravity, mountain climbers are constantly scrambling to find their next step.
8. Cross-country skiing
Skiing anywhere in frigid temperatures would take a lot out of you. But skiing extra long distances and not down an incline: that’s cross-country skiing.