Getting the most out of your gym workout may take a bit more effort than you would think.

Over doing cardio is the number one mistake most people make.

If you’re staying on cardio machines for too long, that may mean you’re not working hard enough. “Decreasing time and increasing resistance can shave off half of your cardio routine,” says Sara Haley, a Global Reebok master trainer and independent fitness consultant.

Also, try mixing up your routine. If you’re a die-hard treadmill jogger, Haley recommends adding high-intensity machines like the rower or the Jacob’s Ladder to your routine; these machines make cardio more efficient by working more muscle groups and burning more calories.

“Employing different planes of motion with lateral trainers like the Ultraslide and the Helix also prevent people from working the same muscles over and over,” says Haley. Diversifying your workout will ensure you give all your muscles some love.

Making sure with your physician that you are fit for exercise insures that your efforts won’t cause injury.