Haley Shapley is a Seattle-based freelance writer, a certified group fitness instructor and the author of Strong Like Her: A Celebration of Rule Breakers, History Makers, and Unstoppable Athletes, a ...

Add Yahoo as a preferred source to see more of our stories on Google. 75 Hard has been a go-to option as a fitness plan and lifestyle challenge for people seeking to be healthier and more productive.

Of all the fitness challenges out there, none are as prolific as 75 Hard. With more than 5.2 billion views across TikTok alone, you’ve likely seen it littered all over your ‘For You’ page or Instagram ...