Pumping a lot of iron may not actually build muscle as well as using lighter weights, a new study says, and this could actually impact your wallet.

According to recent scientific research, new muscle proteins are built faster when adults lift just 30% of the highest weight they can lift than when they lift 90% of that maximum weight, according to plosone.com, a site that publishes peer-reviewed scientific research.

Gym memberships can be pricey, and when you’re shopping for your own weights to use at home, the lighter the weight, the lower the price.

For instance, a pair of 10-pound dumbbells might cost you $24.50 on Amazon.com while 12-pound dumbbells cost $29.50.

The study results are contrary to the idea that fewer repetitions using heavier weights will help you build muscle faster, something personal trainers might tell you.

The downside to using lighter weights? You’ll have to spend more time lifting because you’ll need to lift until you’re fatigued, meaning your muscles are so tired that you can’t perform another rep, notes physorg.com.

On the other hand, if you don't exercise at all check out our story, Avoiding Common Exercise Excuses, which might actually inspire you.

For those who do exercise or are just getting started, read 6 Surprising Exercise Facts, because what may seem like common knowledge may actually be common myths.

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