Health and fitness expert Jillian Michaels created a 7-day challenge for Yahoo readers. Each day features a 7-minute calorie burning, strength building, confident boosting workout.

Day one of the challenge is a full-body workout, with 12 toning and tightening moves packed into seven rigorous minutes. You’ll definitely hit the ground running.

Is the 7-minute workout that's so popular on YouTube legit? We try it, and check in with a personal trainer.

This seven-day glutes workout challenge offers a new set of exercises every day to target your butt muscles for big-time booty gains.

Don't have time to spend an hour working your legs each day? Don't sweat it. Here's a 7-minute leg workout to fit in to any busy day.

This 7-minute leg day conditioning workout from Men's Health Next Top Trainer winner Jahkeen Washington uses HICT principles to challenge your lower body.

Following a freak accident, Scarlett Espinoza, 38, suffered a triple ankle fracture. To recover, she joined a workout ...

The scientific 7-Minute Workout is designed to boost your metabolism and improve strength to get you in shape.

Fitness Legs and Arms Strength Workout Add some weight and take these moves slowly for an extra challenge.