Every day Elya carried the little piglet up the mountain and sang to it as it drank from the stream. As the pig grew fatter, Elya grew stronger.
—Holes, by Louis Sachar
One of the classes I teach is a strength training class. You choose dumbbells, and unless you want to leave the fitness room and go dig something up on the main floor, your choices are 2.5-, 5-, and 7-lb weights. Not all that heavy. That’s because the class is a low weight, high rep class where I make you do the same movement 20-40 times. What that does is work your slow-twitch muscle fibers, which give you muscular endurance.
That’s awesome. It teaches your body and muscles not to get fatigued too easily.
It’s not a strength building class, though. You’re not really working your fast-twitch muscle fibers, which are the ones that kick in if all of a sudden you’re hit with a huge load of weight. So you need to do both. And even with the low weight, high rep class, at some point you’re probably going to want to go up a weight, or at least have a slightly heavier one for when we do lower body work and you’re just letting your weights hang out on your trapezius. (I only ever use 2.5-pounders, but that’s because if I did something heavier, I’d be paying attention to my workout, and it’s the class I’m supposed to be giving my attention to. I do other strength work on my own time.)
So, to build muscular strength you need to find weight that you can only hold for a maximum of about five times before you reach failure. If you’re at a gym, this will take you a little while to look around and test things out, and it’s likely that with whatever type of lifestyle you have or activities you already do, you will find that you need much heavier weights when working some muscles than others. Just make sure you test them out, and as you get stronger, don’t get complacent. Keep using gradually heavier weights and then you’ll always have a challenge, rather than a plateau.