How to Do It: Start with your left leg on a bench or chair, positioned for a Bulgarian split squat. Hold a dumbbell or kettlebell at your right shoulder, core tight.

4. Leg Press The leg press develops the quadriceps, gluteus maximus, hamstrings, and calf muscles. It builds leg strength and corrects muscle imbalances, such as those in the hamstrings. To do it: Sit ...

There's no magic number for how long your workout should go for muscle and strength gains. Here are the factors that play into how long you should work out.