You Don’t Need Big Weights To Build Your Muscles
We’ve all heard the advice: If you want to build muscle, you’ll have to lift heavy weights. And the heavier the better. But is that true?
Researchers at McMaster University don’t think so. They hypothesized that as long as you exercise until failure (when you can’t lift any more), it doesn’t matter how much weight you lift. But hypotheses are only bets, so they set out to test it.
The researchers followed two groups of students in the gym. One was given the typical instructions for weight training: lift weights that use 75–90% of your maximal strength, so that only 8–12 repetitions can be done before failure.
The second group was told to lift weights that used only 30–50% of their maximal strength, so they could lift twice as many repetitions (around 20–25) before failure. Three months passed and the researchers’ hypothesis was validated. According to measurements of muscle fiber cross-sectional area biopsies from arms and legs, heavier weights weren’t significantly better at building muscle.
Here’s the catch: Although heavy versus light weights may not affect how much muscle you build, it can affect how much strength you gain. That’s because the size of your muscle isn’t directly proportional to your strength. You see, there are two types of muscle; “fast twitch” (type 1) for strength, and “slow twitch” (type 2) for endurance. The same mass of fast twitch muscle will be slightly stronger than an equal mass of slow twitch muscle (but it will also become tired sooner).
The way that you exercise affects what type of muscle you build. Marathon runners build more slow twitch muscles in their legs when they run long distances, but most weight lifters build a higher proportion of fast twitch muscles by doing squats. Nobody has all fast or slow twitch muscles, but our bodies adapt to how we use them.
So working out with smaller weights will build a different ratio of strength and endurance than heavy weights would. Practice what you want to improve. If you want to build strength, lift heavy weights, and if you want to build stamina, exercise with lighter weights (or your body weight) for a longer period of time.
