Muscles are what gives us our ability to move. Every movement we make is powered by a specific set of muscles. For example, if I decide to lift my arm up in the air, my bones move which causes the arm to go up. But the bones don't simply move by themselves. The muscles move the bones. The muscles are attached to bones by strong, stretchy cords called tendons, which will convert the force from the muscle to the bone which will then produce movement. We won’t go into too much detail, but if we zoom into these muscles, we see that they contain a bunch of muscle cells (muscle fibers) that themselves are filled with thousands of protein- packed units called sarcomeres. Sarcomeres are the basic units of muscle contraction, they are what give muscles their function.

We have over 650 of these muscles in our body, different shapes, different sizes, different functions. They are everywhere, legs, arms, hands, face, ears, neck, butt, … The largest muscle in our body is the butt muscle, scientifically known as the gluteus maximus and it is thousands of times larger than the smallest muscle in our body, the stapedius, a muscle in our ears. This hopefully gives you some perspective.

Now many of these muscles are gathered together, in specific parts of the body, and form small groups called muscle groups. Let’s take the calves muscle group as an example. The calf muscle group consists of three muscles located at the back of your lower leg. Together, they help you point your toes downward, a movement that's essential for walking, running, and jumping. If you’ve never noticed, try standing up and walking for a bit. With every step, there’s a moment when you push off the ground with your feet, briefly standing on your toes. This movement is made possible by your calf muscles. If you are reading this while holding your phone, I would imagine your arm is most likely bent right now and therefore flexed. A flexed arm is when you bend your elbow so that your hand moves closer to your shoulder. If this is the case then your arm flexor muscles are working and contracting. This movement is powered by the arm flexor muscle group. One of the members of that group you may have heard of already: the famous bicep muscle. You’re probably familiar with the bicep, one of the main muscles in this group. But there are also two other important muscles: the brachialis, which sits right beneath the bicep, and the brachioradialis, which runs further down the arm.

Let’s take the arm flexor muscles as an example. Everyone can flex their arm without any weight. It feels easy because there’s no added resistance—no opposing force. It’s effortless for the muscles, and since they aren’t being challenged, there’s no reason for them to grow stronger or bigger. So the goal is to challenge them by adding resistance. You want to choose a weight that challenges your muscles, a weight that is difficult but still manageable. Manageable because your muscles should still be able to perform the arm flexing movement for a set number of repetitions. If the weight is too heavy, you won’t be able to produce any movement, and the muscles won’t be working effectively. Research shows that the best way to train for muscle growth is by performing 8–12 repetitions per set, for about 3 sets (Rests of 1-2 minutes between each sets). So by selecting a weight that makes completing 8–12 repetitions, 3 times, difficult, you're forcing your muscle fibers to work hard, which is exactly what you want.

So, you've done your repetitions, and now it’s time to understand what happens next. When you perform the movement with challenging resistance, it causes small micro-tears in the muscle fibers. This is a good thing. These tiny tears trigger a repair response in your body. Your muscles are basically saying, “Wow that was tough, let’s make sure we are better for next time.” After your workout, your body starts the repair process. It uses molecules called amino acids—the building blocks of protein—to repair and reinforce the damaged fibers. This process makes your muscles stronger and slightly larger. This is your body’s way of adapting, ensuring that the next time you face the same challenge, your muscles will be better prepared to handle it. This process is called muscle hypertrophy, and it’s how your muscles grow over time.
As your muscles become stronger, they’ll need even greater resistance to continue growing. That’s where progressive overload comes in. Progressive overload is simply the process of consistently increasing the challenge—by adding more weight or resistance—to push your muscles to adapt and grow. This is the key to continuous muscle growth and strength development.

But here's something crucial: recovery. Muscle growth doesn’t happen in the gym, it happens during the repair process when you rest. So, it’s just as important to allow enough rest between workouts. Experts usually recommend not training the same muscle group two days in a row, because your muscles need time to fully rebuild and come back stronger.

You might have also heard people talk about the importance of good form during a workout. Good form is crucial for two main reasons: preventing muscle injury and making your workout as effective as possible. Take the bicep curl, for example. It's one of the most common exercises to work the flexor muscles of your arm. To get the best results, you want to make sure your biceps are doing all the work. This is where form comes in. If you start bending your back while doing the curls, you’re cheating yourself by using your back muscles to help with the movement. This means your biceps aren’t getting the full challenge, and you're potentially risking injury.To keep the focus on your flexor muscles and avoid using your back, make sure to keep your back straight. This way, your biceps will be the main muscle doing the work, helping you get the most out of each repetition and reducing the risk of injury.

While we haven’t talked much about diet, it’s important to mention that consuming an adequate amount of protein plays a key role in muscle growth. As mentioned before, the amino acids from protein provide the building blocks your muscles need to repair and grow after a workout. As long as you're eating a balanced diet and getting enough protein for your body’s needs, you should be fine. It's not about overloading on protein—just making sure you're getting enough to support your training and recovery.

That’s the basic understanding you need if you're looking to build bigger muscles. We used the arm flexor muscles as an example, but the same principles apply to all muscle groups.

When training, it’s important to work all the major muscle groups for a balanced routine. These include the chest, which can be strengthened with exercises like push-ups and bench press; the back, which benefits from exercises like rows and pull-ups; and the shoulders, where exercises like shoulder presses and raises help build muscle. To work your abs, try crunches, planks, and leg raises. For the arms, bicep curls target the front of the arms, while tricep exercises like dips and pushdowns work the back of the arms. Lastly, leg exercises like squats, lunges, and calf raises help strengthen your thighs, glutes, and calves.

Muscle growth is driven by a combination of resistance training, progressive overload, recovery, and proper nutrition. By challenging your muscles with the right amount of weight and focusing on good form, you create micro-tears in the muscle fibers that lead to repair and growth. For optimal muscle development, aim for 8–12 repetitions per set, with about 3 sets per exercise, and rest for 1–2 minutes between sets to allow your muscles to recover slightly before the next round. Progressive overload ensures continued muscle development as you gradually increase resistance over time. Rest is equally important, as muscle growth occurs during recovery. Additionally, a balanced diet with adequate protein supports the repair process. With these principles in mind, consistent training and recovery will help you build stronger, larger muscles.