Let’s first think in terms of progressive resistance. As we get stronger, we need to push ourselves harder in our workouts. That means lifting heavier and heavier as time goes on to challenge our muscles. With weights, it’s fairly straight forward to do as long as you have access to a rack of dumbbells spanning a variety of weight —you just go up in numbers as your strength increases.

It’s also possible to achieve progressive overload using only resistance bands. Except, instead of needing a full wall of bulky weights spanning 5 to 100+ lbs., you need a handful of resistance bands that can fit in a single backpack. With a set of resistance bands ranging from extra-small to extra-heavy, you can progressively go heavier in your workouts as you get stronger. With enough dedication and a healthy lifestyle, you can see the same results with five bands as you would expect with a huge range of free weights.

Side-note: Before we go on, we’ll note that resistance bands are similar to resistance tubes; close relatives, if you will. The major difference is that resistance bands are flat and form a full loop, while resistance tubes are cylindrical and have handles on each end. We work with looped resistance bands, but when it comes to resistance bands vs tubes, consider them as mostly interchangeable.

The innate versatility of resistance bands is partially due to their linear variable resistance. This means that as you stretch a band, it gets heavier. Take a rubber band, for instance. When you initially remove the slack, the band is bouncy and malleable. The farther you stretch it, however, the more tension you feel, and the more force you need to use to keep it taut. Resistance bands are just the same. Interestingly, this aspect of resistance band training happens to be one of the most beneficial in terms of gaining muscle. Because the band increases in weight the further you stretch it, any given resistance band exercises’ resistance pattern matches the natural strength curve of our muscles.

Wait, what?

Envision yourself doing a curl. At the bottom of the curl, the weight feels pretty dang heavy. Sometimes, getting past that initial sticky point requires a micro cheat-swing or even a spotter’s aid. That’s because we’re typically weaker at the bottom. As our hand moves up past that weak point, our bicep engages and we’re able to get through the whole curl motion.

With bands, that weak-point issue doesn’t exist. Due to linear variable resistance, the band is lighter at the bottom with more slack. As you move your hand upward into the curl position, the weight increases. Resistance bands allow you to feel the tension when you want it—when it’s most beneficial for strength building. That’s why powerlifters commonly use resistance bands in combination with free weights: to efficiently improve the strength in their squat, bench press, and other moves.

To bring this point one step further, bands offer something that free weights don’t: constant tension. At the top of that same curl, there’s another lull-spot. With weights, you can easily rest in that position with little to no effort due to the composition of your arm. However, that’s where you should be contracting the muscle the most in order to gain the most from that particular exercise.

With resistance bands, you’ll feel tension throughout the entire range of motion. You don’t have to rely on gravity as you do with free weights to create the resistance. The constant tension that resistance bands offer is extremely important in building muscle, spurring a degree of metabolic stress and pump, which free weights lack.

Another key benefit of using resistance bands for building muscle is their ability to work in multiple planes. With free weights, resistance only applies in one vertical plane — that’s due to our dear friend, gravity. To do a bench press, for instance, you must lay on your back and press the weights directly upwards to feel the tension.

With bands, we’re not confined to gravity’s pull on a dumbbell to feel that resistance. The bands themselves are the resistance. Stand up, lay down, heck, hang upside down if you really want, it doesn’t matter. In pulling the band, we can achieve the tension we need to build muscle in any plane.

This benefit really comes into play when considering function. Take a big football player. In a gym, he could bench 400 pounds for 10 reps, maybe. But once you stand him up tall, the strength doesn’t translate the same way. What was strength-focused solely in his upper body now applies to his entire body. Starting from the ground up, he now will need to engage his feet, legs, and core to stabilize and energize through the exercise. For this reason, resistance band training is a technique often adopted by professional athletes from baseball players to martial artists to increase core stability and full-body power.