While it’s important to warm up, you don’t want to overdo it. If you runfor an hour before you start a training session, your body is going to be too fatigued for what your trainer has planned, says Kathy Kaehler, Ace Certified Trainer and fitness author. She recommends limiting your cardio to 10 minutes if you’re heading in to a session, or have a weights or circuit routine planned for yourself.
(And if you think a super-quick run won’t yield any benefits, think again: A 2014 study published in the Journal of The American College of Cardiology found that people who ran for just 5 minutes a day at a leisurely pace gained an additional 3 years of life compared to those who never ran.)
Using the scale as your only indicator of success.
If you’re working hard but the numbers on the scale aren’t going down, don’t despair. Many clients lose body fat and gain muscle, Luepke says. It’s much more important to pay attention to the way that clothes fit, and how you look, feel, and move, she explains. Focus on what you’re newly capable of doing—like owning hills during your run, walking up and down stairs without pain, or hauling grocery bags out of the car with ease.
You should also avoid weighing yourself every day, says Jamie Atlas, a certified trainer and fitness studio owner. Your weight is going to fluctuate depending on what you may have eaten that day or where you are in your menstrual cycle. Stepping on the scale once a month is a better bet, he says.
Showing up hungry.
Afraid you’ll get sick if you eat before a sweat session? Arriving at the gym with an empty stomach isn’t a great idea. “Your body can’t perform without gas in the tank,” Kaehler says. She recommends eating some carbs and a little bit of protein, like a piece of whole grain toast with almond butter. It’s enough to give you energy without filling you up too much.
And try to avoid overdoing it after you exercise. Perhaps not surprisingly, a 2009 study in Physiology & Behavior found that some people have an enhanced desire for food after exercise, and may overcompensate. A good bet? One of these 10 smoothies, all packed with the protein you need to build muscle and carbs to restore the glycogen you burned during exercise.
Showing up sleep deprived.
If you truly couldn’t catch a wink the night before, sleeping in might be a better bet than forcing yourself to show up to the gym. Your body needs time to repair and rejuvenate, Kaehler says. One study published inPhysiology & Behavior showed that not getting enough shut-eye can lead to impairment in reaction times. Risk of injury goes up due to response time slowing down.
Cranking the elevation on the treadmill too steep.
If you’ve ever cranked the treadmill elevation so high that you have to hold on to the bar, you’ve gone too far. This puts your body at such an angle that pressure is great on the back, hips and knees, Kaehler says. Instead, bring the elevation down so you can comfortably move without hanging on to the bar, then increase your walking or running pace, she says.
Squat with improper form.
Of all the exercises, why single out squats? Because it’s one of the most functional movements we do in everyday life, says Mike Luepke, a certified personal trainer and personal training studio owner. We reach for something on the lowest shelf at the grocery store, bend down to pick something up, and sit on the toilet regularly. That’s why it’s important to get your body in the habit of doing it right. It’s common for people to shift their weight toward their toes, jutting their knees out. Instead, shift your weight to the heels and stick hips back, he says. This will distribute weight and keep excessive pressure off your knees, safeguarding you against pain and injury. Plus, it will help strengthen your glutes—an under-developed backside can lead to knee and low back pain, because these muscles try to compensate, he explains. Properly developed glutes will take on the load, protecting the knees and back.