No matter if you’re an occasional gym-goer or a committed Crossfitter, there are a few moves everyone should be able to do with ease. They serve as a foundation, and chances are, you’re already doing a version of them every day without even knowing.

For example, tons of everyday movements are essentially a squat. “We’re always up and down, sitting down and standing up,” says Paul Pooh, trainer and injury prevention specialist at The Sports Center at Chelsea Piers in New York City. Picking up something you dropped or lifting your pet off the ground are both good examples. And even though you’ve been doing it since you were a kid, there’s still a right and wrong way (more on that later).

You should also feel stable doing a single-leg or unilateral-leg movement like a forward lunge. It sounds technical, but again, you do it all the time when walking or climbing stairs.

To get a better sense of your current strengths and weaknesses, try doing the five moves below in front of a mirror or with a friend who can monitor your form.It’s similar to an assessment a trainer might give you during your first session (but free!).First, we show you the move performed correctly, and then you’ll see common mistakes that not only make trainers cringe, but also may put you at risk for injury.

1. Push-Up

Why? Assess upper body and core strength.How-To: Start in a high plank position, with wrists under shoulders, back flat, and core engaged. Bend your arms and drop your chest toward the floor. Focus on getting your arms to bend to 90 degrees, so your chest is just a few inches off the ground, before you push back up. To modify this move, drop to your knees. For a more detailed explanation, check out a demonstration here.

Common Mistake: You’re barely bending your arms.

What It Means: If you’re not able to bend your elbows much, and therefore can’t really lower your chest to the ground, this indicates a lack of strength in your major arm muscles (biceps, triceps), shoulder girdle (trapezius, deltoid, rotator cuff, rhomboids), and chest (pectorals).

Common Mistake: Your hips sag.

What It Means: This generally indicates a lack of core strength or that you’re not engaging your core. To activate these muscles, think about bracing your core (contracting the muscles as if you were about to take a punch), and pulling your belly button in toward your spine. If your lower back arches or sags, this could also mean you’re not engaging your glutes.

2. Squat

Why? Assess hip flexibility, lower body strength, and balance.How-To: Start with feet parallel and hip-width apart. Make sure you’re standing with a neutral spine, hips over knees, knees over ankles. Extend both arms in front of you for balance. Brace your core and send hips back first, then slowly bend your knees to lower into a squat. Maintain a neutral spine throughout. For a more detailed explanation, check out a demonstration here.

Common Mistake: Your knees are too far forward and hips are not that far back.

What It Means: Trouble hinging your hips back or lowering your butt to the ground indicates tightness in the lower part of your body. It could mean your hip extensors or hamstrings are tight, and you need to work on hip flexibility.

Common Mistake: Your knees buckle in as you lower or stand.

What It Means: If your knees are turning in to the midline of your body, it generally means you need to strengthen your gluteal muscles and hamstrings.

3. Dumbbell Overhead Press

Why? Assess shoulder strength and range of motion.How-To: Hold one dumbbell in each hand, with wrists turned in to face each other and dumbbells level with your shoulders. Keep knees soft and core engaged. Press weights up overhead, focusing on fully extending your arms, before lowering the weights with control to your shoulders. For this assessment, pick a weight with which you can perform at least 8 to 12 reps.

Common Mistake: Your arms come forward instead of staying directly overhead.

What It Means: You may not have a normal range of motion in your shoulders, and your shoulder girdle and back muscles (trapezius, rhomboids, rotator cuff, posterior deltoid) may not be working hard enough to keep your arms in line. With proper form, your biceps should be in line with your ears.

Common Mistake: You arch your lower back excessively as you raise the weights.

What It Means: Typically, this means you have a lack of core stability and core strength, or that your hip flexors (the muscles on the front of your pelvis) are tight and not allowing you to keep your hips directly over your knees.

4. Forearm Plank

Why? Assess core strength.How-To: From a facedown position, use your forearms and toes to lift your entire body off the ground. Engage your core, and keep elbows directly under your shoulders and forearms and hands parallel. Maintain a neutral neck position, keeping your back flat and ankles flexed at 90-degree angles. For a more detailed explanation, check out a demonstration here.

Common Mistake: You hike your hips.

What It Means: Whether your hips sag or you hike them, the issue is basically the same: a lack of core strength.

Common Mistake: Your shoulders are not directly over your elbows.

What It Means: Leaning back, so that your elbows are more forward, might feel easier, but it’s actually putting excessive strain on your shoulders. It also means you’re not engaging the muscles that surround your shoulder blades (i.e. not ‘packing’ them), and the muscles of your shoulder girdle may be weak.

5. Forward Lunge

Why? Assess balance, coordination, and equal strength on both sides of your body.How-To: Stand with feet hip-width apart and step forward with your right leg. Lower into a lunge position, so that both the front and back legs are (ideally) bent to 90 degrees. Your upper body should be straight (not leaning forward or back). Hold this position for a moment, then push off the right foot and return to stand. Repeat on the other side. For a more detailed explanation, check out a demonstration here.

Common Mistake: You don’t take a big enough step.

What It Means: When you don’t step far enough forward, you may put extra weight on your toes, which means excessive pressure on your knees and hips—it’s also harder to balance like this. Work on strengthening your glutes, hip flexors (so you can bend deeper), and hamstrings (so you can take some of the pressure off the front of your legs).

Common Mistake: You lean too far forward with your chest.

What It Means: Though it is acceptable for your chest to come forward slightly (the same type of motion as when you’re walking or climbing stairs), leaning too far forward can be an indication of weak glutes and core, or an over-emphasis on the quads. Remember to engage your glutes and hamstrings as you perform the movement.

Special thanks to our model, Amanda Butler, who also designed these moves. Amanda wears a Lululemon top, Fabletics pants, and her own Nike shoes.