A top personal trainer shares 3 common mistakes people make when trying to build muscle

Harley Pasternak strength trains for 20 minutes, six days a week. Harley Pasternak The celebrity trainer Harley Pasternak says common gym mistakes can hold back muscle gains. Progressive overload is key to building and maintaining muscle. Pasternak said that giving muscles enough time to recover between workouts is essential. Harley Pasternak has spent 30 years helping people build strength and muscle. In that time, the 51-year-old Los Angeles-based personal trainer, who has worked with Kim Kardashian , Rihanna, and Robert Pattinson, has seen people making the same mistakes, which keep them from making the gains they want to see. Progressive overload , which means challenging your muscles more and more over time, whether through heavier weights or more reps, is crucial to building muscle , but there's more to it than just that, Pasternak told Business Insider.