The human body is smart: It will always take the path of least resistance to get things done. This is all too clear to fitness professionals when training clients -- beginners and veterans alike -- who exhibit faulty form on basic exercises. 

For example, if you're trying to squat but you have weak glute muscles, your body will recruit muscles from your lower back to compensate. Why is that bad? Because you can more easily injure those muscles that are trying to compensate for weaker muscles. Even if you skirt injury, you won't get the most out of an exercise when you have bad form.

Since the ongoing coronavirus pandemic makes it hard or impossible to see a personal trainer or attend group fitness classes with professional instruction, I identified some of the most common fitness mistakes I see in four foundational exercises: the squat, deadlift, push-up and shoulder press. In this guide, I cover common mistakes in detail and explain exactly what you need to do to fix them.

Squats

Everyone should master the squat. Squatting is one of the most foundational, functional movement patterns known to man, yet most of us have lost our ability to access the squat position. This happens when we spend most of our time sedentary and lose mobility in our hips, ankles and spine. 

For some people, anatomical differences play a role in how difficult it is to drop into a squat (e.g., the positioning of the ball-and-socket joint of your hips), but even those with the most squat-resistant bone structure can learn to access deep, comfortable squats.

Mistake 1: Torso collapses

Fix it: Improve hip, ankle and spinal mobility, as well as core strength.

As a personal trainer, the forward lean is easily the most common squat fault I see. This occurs when a combination of inflexible joints and weak core muscles prevent you from holding yourself upright in a deep squat. Your hips and ankles don't allow for a large enough range of motion, while your core (abdominals and back muscles) can't support your spine. Weak glute muscles may also cause you to lean forward.

To fix a forward lean, you'll need to improve mobility in your hips, ankles and spine, as well increase your core strength. Here are some follow-along videos that can help you get started:

Mistake 2: Heels come off the ground

Fix it: Improve ankle and hip mobility.

If you cannot keep your feet flat on the ground during a squat, that's another common sign of limited mobility, particularly in the ankles. Hip mobility and spinal mobility limitations can also contribute to your heels raising off of the ground. 

To fix this common squat mistake, spend a lot of time on your ankle mobility, but don't neglect your other joints. When it comes to squatting, optimal mobility in all joints (even your upper body) plus great core strength leads to faultless form. 

Here are more ankle mobility exercises for people who struggle to keep their heels on the ground during squats: 

Push-ups

While push-ups don't necessarily mimic day-to-day actions, they develop strength in your core, chest, back and shoulders. Push-ups teach you to stabilize your core muscles to protect your spine, as well as how to keep your body in alignment, which can encourage better posture.

Mistake 1: Elbows flare out

Fix it: Strengthen triceps and muscles surrounding the scapulae. 

When you do a push-up, your elbows should point backward or just slightly outward (up to a 45-degree angle with your torso). Flared elbows, especially if they're flared to a 90-degree angle, indicate weak triceps and weak upper back muscles, the latter of which contributes to rounded shoulders. Rounded shoulders knock your spine out of its natural alignment and, over time, can lead to pain and immobility. 

To avoid flared elbows, strengthen your triceps (the backs of your upper arms) and the muscles surrounding your scapulae (shoulder blades). The exercises in the following videos should help.

Mistake 2: Core collapses, spine arches

Fix it: Strengthen your core.

If at any point during a push-up your back arches towards the ground, you need to work on your core strength. When your spine hyperextends in the push-up position (at the top or bottom), it means your core can't support your spine. 

If you can't perform standard push-ups without arching your back, start with wall push-ups and progress to knee push-ups and then elevated push-ups. There's no shame in modifying a movement -- it's the smart way to start, so you don't develop bad habits or sustain an injury. 

And try out these core-strengthening exercises that can improve your push-up form:

Deadlifts

Deadlifts come in a close second for "most functional movement." Think about how often you bend down to pick things up -- you're essentially doing a deadlift every time. Mastering the deadlift teaches you how to safely pick heavy objects up from the ground, while protecting your back. 

Mistake 1: Spine rounds in starting position

Fix it: Practice deadlift technique, improve hip mobility.

All it takes is some technique practice to correct a rounded spine in the starting position of the deadlift. Many beginners don't have the body awareness needed to realize that their back isn't flat. This mistake sometimes happens, however,a due to a lack of hip mobility. If you can't "sit" low enough in the starting position, you'll naturally compensate by rounding your back to reach the weights. 

Practice your deadlift technique and improve your hip mobility with these exercise demos: 

Mistake 2: Back arches at the end of the rep

Fix it: Practice core alignment exercises.

Like the first deadlift mistake, arching your back in the finish position is often the product of poor body awareness. Beginners may not realize that they're actually pulling too far and ending up in this hyperextended position. When you finish a deadlift, your spine should remain in a neutral position (not arched and not rounded). 

You can fix this fault by practicing core alignment. When your core is in alignment, that means your upper back, lower back, abdominals, hip flexors and glutes create one solid, strong cylinder around your spine. Stand up and follow these cues to achieve core alignment:

• Take a deep breath 
• Pull your shoulders back and down
• Tuck your tailbone slightly (get rid of any anterior tilting)
• Squeeze your glutes
• Draw your belly button into your spine
• Activate your ab muscles 

Need a visual? Check out this video demonstration with multiple different cues that all explain how to engage your core.

Shoulder press

Another highly functional movement, the shoulder press is important for daily activities, such as putting a heavy box up on a shelf. This movement can develop strength and stability in your upper body and core -- if you do it right. 

Mistake 1: Arms don't fully extend overhead

Fix it: Improve shoulder and upper back mobility.

Sometimes, not fully extending your arms overhead at the top of a shoulder press happens simply because the person is unaware that they aren't fully extending. This can be fixed with some practice and body awareness. 

Some people can't fully extend their arms overhead, however, due to limited shoulder mobility. That can develop after an injury or happen just because you aren't moving your shoulders enough (just like hips can get tight when you sit all day). Your middle and upper back (thoracic spine) can also become tight and rounded due to poor posture -- if you feel a pinching sensation in your upper back when you try to raise your hands up high, you know you need to work on your T spine. 

Try the shoulder mobility exercises in these videos: 

Mistake 2: Back arches 

Fix it: Strengthen your core

Are you starting to notice the trend that many common exercise mistakes happen due to weak core muscles? When you have weak core muscles, your body will compensate by pushing the hips forward and lifting the tailbone (anterior tilt), as well as hyperextending the spine (arching) to stabilize the weight traveling above your head.

Shoulder presses shouldn't hurt your back. This mistake is so common that many people think it's normal to end a set of shoulder presses feeling like their spine has been compressed -- it's not normal. It means you need to work on your core strength. 

For shoulder presses specifically, you need to learn how to tuck your tailbone, squeeze your glutes and draw your navel into your spine. This creates an extremely strong, stable cylinder that protects your spine. You won't look cute while you're doing this, but you will get stronger and stay free of injuries. 

These core strengthening videos can help you improve your shoulder press: 

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.