Make it harder: Use a heavier weight, increase the speed (power), or hold the end position for 2 seconds before returning.

We're definitely fans of exercise snacking, but sometimes nothing but a long, sweaty workout will do — and if that's what you're craving, this 45-minute high-intensity interval training workout with ...

Try this knee-friendly 35-minute workout, requiring no equipment, designed to burn calories and build strength safely.