The plank challenge is one of the most effective 30 day fitness challenges around — it's extremely time - efficient and consists of only 1 exercise. (fitnessandpower.com)
BUT I will admit, I'm starting an 8 week fitness challenge today that includes a meal plan. (treatswithatwist.com)
If you take my Bathroom Fitness Challenge you will actually burning WAY MORE than 50 extra calories per day. (femfusionfitness.com)