An Intro to Functional Fitness: Core Strength

AKA how to start exercising regularly without injuring yourself, from a former sedentary individual and a present-day klutz

If you’re this person…


or this person…


…this is your rookie guide to having a healthy quarter-life crisis, rehabbing an injury from that New Year’s resolution spin class, starting a sport, or getting into a new exercise routine for the school year.

Exercise is great! But hold your horses for a sec. Injury rates from spin class, CrossFit, and other intense fitness classes have been on the rise. Many of these injuries occur because of muscle fatigue. Controlled, measured muscle fatigue is necessary to strengthen and grow muscles, but overdoing it can do more harm than good. Sometimes, an overworked muscle gets pulled. Also, when your muscles are tired, it’s much easier to lose balance while stepping into a lunge, accidentally spraining your ankle or toe. When you suddenly start pushing your body a lot harder than normal, the chance of getting injured increases significantly.

There are three key components of being functionally fit.

  1. Cardiovascular fitness
  2. Core strength/stability
  3. Flexibility

Does walking briskly or running for several blocks or make you out of breath? That’s number one. Does lugging around hefty grocery bags make you sore or achy? Work on the second one. If you slip on ice and step farther than expected, do you feel like you’ve pulled something? That third one has come knocking.

A couple quick rules of engagement.

  1. This is the framework I have come up with to work on my own physical fitness, developed from my experiences starting to seriously play a sport (Ultimate Frisbee), learning how to work out, and learning how to recover from injuries over the last three years. Granted, I’m not a physical trainer or a physician, so take this guide accordingly.
  2. All of the exercises and stretches I cover below are doable in your own home without any equipment other than some clear floor space. They are also relatively easy to do with no prior degree of fitness. Exercises in each muscle group are listed from beginner to regular gym-goer.
  3. Warm up before doing any exercises or stretches. If you’ve ever tried to stretch a cold rubber band, you’ll know why. Warming up beforehand allows for a much greater degree of motion while you’re actually exercising.
  4. As a rule of thumb, for these exercises, start with three sets of five. (If doing this regularly for a week causes no abnormal muscle tension or soreness, increase the number of reps from there. If this is new to you, you should feel slightly sore the next day, but not so tight that walking to work or picking up your bag should cause pain.)
  5. Do not do anything that causes sharp pain. If an exercise is causing sharp pain, rest your body and see a physician if necessary.

Cardio fitness is not difficult to improve. Do whatever cardio you enjoy (biking, swimming, walking, jumping rope, dancing etc.). Start from an intensity that is not hard, and slowly ramp up from there. Do not assume that four years of couch potatoing adequately prepares you for spin class, Barry’s Bootcamp, or running a 10k at the snap of your fingers (or the snap of a New Year’s resolution). (Have tried. Can attest that it is a terrible idea.)

Onwards. Stability is basically how much control you have over your body. When you move, you should always be balanced and stable as you transition from one position to another. When you sit or stand, you should be positioned with your head over your shoulders over your hips and your knees over your ankles.

These are the key muscle groups to make your body more stable: core, back, glutes & quads, and arches of your feet.


Your core and back support your spine. Unlike other parts of your body, like your upper back or your legs, your lower back is not supported by a lot of bone structure. While the absence of bone structure gives humans the ability to fold over, lean back, of swivel side to side, it also means that the structural support has to come from elsewhere. In this case, that support comes from your abdominal muscles and your back muscles. A tighter core means that when you step forward, your torso moves together, without ever leaning too far forward or backward. That means you’re less likely to lose your balance. In addition, if your core/back muscles are weak, you often end up slouching, which strains muscles and tendons and often leads to chronic back pain.

Ab Contractions:

Great, gentle warmup. Lay flat on your back in a sit-up position, with no gaps between your back and the floor. Slowly activate your abs for 2–3 breaths, then relax without arching your back. If you can’t find your ab muscles, imagine sucking in, pulling your navel to the floor.

Single Knee Presses:

Also a good warmup. Lay flat on your back in a sit-up position. Bring your right knee up to your chest. Place your right palm on your right thigh, fingers parallel to your leg. Simultaneously, use your abs to pull your knee towards your chest and use your palm to push your knee away from your chest. After 2 breaths, relax your hand and bring your foot back to the ground slowly, without arching your back. Same deal on the left.


Start with three sets of ~30 seconds. Lie flat on your belly. Place your forearms on the ground, parallel to your body, with your elbows directly below your shoulders. Tuck your toes under your ankles so your toes face forward. Push off the ground so the only points of contact are your toes and your forearms. The key thing to focus on here is to always maintain a straight back. Engage your core. If your back starts to sag, you’re putting a lot of pressure on your lower spine, which shouldn’t be doing any work. Your abdominal muscles should be doing most of the work.

Dead bugs:

Lie flat on your back. Raise all of your limbs to be perpendicular to the ground (like a dead bug). Lower your left leg and and right arm at the same time, without ever letting your back arch off the ground. Suck your stomach towards the ground. Bring your leg and arm back up, and do the same with the opposite limbs. To get started, you can do this exercise with bent legs. Once your abs are stronger, do it with straight legs. This is a good one to work your obliques, the abdominal muscles that make it easier and safer to twist side to side.


Src: the Pusheen page, edits by Brian Truong

Deadlifts (no weight):

Stand tall, with feet slightly more than hip width apart. Slowly bend at the hips, keeping your back straight, as you move down. As you move down, bend your knees slightly (keeping knees in line with ankle and hip), just enough so that when your back is parallel to the ground and you let your arms reach down, they’re about six inches from the ground. Like in a small squat, your knees should not go past your toes, and your butt will be slightly behind your feet. At the down position, your back should still be straight. You should be able to look forwards. From this position, return to standing.


If you have flat feet like me, you’ll know what it looks like when your ankles sag in. Your arch is flat on the ground and your ankle is over the inner side of your foot (over pronation). If you have high arches, your ankle will be over the outside of your foot (over supination).

The most stable position for your ankle is in the middle. Your arches should be slightly off the ground. From the back, your ankle should be right above your heel. The first exercise is a great way to find this position.

Arch pulses:

Place a quarter underneath the ball of your big toe. Try to squish the quarter, while balancing by pushing into your heel. Relax your arch. That’s one rep!


Balance on one foot for 30 seconds. Take note of the exercise above, and make sure your arch is active (squish the quarter!). If you’re feeling super stable, try this on a squishy gel pad or do a small squat.


What are glutes good for? If you stand in a slight squat position with feet shoulder-width apart, it’s actually pretty easy for someone or something unexpected to push you off balance. A particular weak point? The knees. If something rams into your knee from the side, for most people, your knee collapses down and inwards, likely injuring ligaments in your ankle and knee. However, if you make a few adjustments to that stance, you can improve your balance. Apply a slight torque, while engaging your arches and glutes, by rotating your knees outward so they’re in line with your pinky toes. Now that unexpected collision won’t throw you off balance.

Glute bridges:

Back to sit-up position. Engage your core and slowly lift up from the pelvis. In the up position, your body should form a straight line from your shoulders (which are still on the ground) to your knees. Hold this position for 2 breaths, and then return to the ground.

Baby squats:

Stand with feet slightly wider than hip width apart, toes slightly turned out. Keeping your shoulders straight, bend your knees slightly, to ~145º ankle. Keep your arches active. Make sure your knees, hips and ankles are in a single plane, and make sure your knees don’t go past your toes. Return to standing. In addition to being good for your glutes, this is a pretty good quad exercise. Stronger quads lock in your knee, so your knee won’t shift side to side or be twisted as easily.

Liked this article? If you’re interested in another fitness article about how to stretch and take care of your muscles (number 3 on that list), let us know by liking this one! After you’ve done that, follow us on Medium to make sure you don’t miss the article when it comes out. Any suggestions/questions related to beginner’s fitness? Leave a comment down below!

Happy exercising!

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