Show off your muscles, you earned them! (Photo courtesy Ericka McConnell)
1. Heavy weights make you bulk up: It's a common belief: lifting heavy weights will have you looking more bodybuilder than long and lean. But in reality, your muscles won't get Ms. Olympia-sized from lifting a 20-pound kettlebell; the size of your muscles is related to your genes and strength-training routine, not the size of your weights. Using heavier weights actually saves you time — studies show that you will get the same results when lifting heavier weights for fewer reps as you do with lifting lighter weights for longer. But no matter what size weight you use, make sure you choose one that is challenging your body the right way. The American Council on Exercise recommends that you choose a weight that fatigues your muscles within 90 seconds (aka makes you unable to perform another rep correctly), since that's within the limit of your muscles' supply of anaerobic energy.
2. Soreness comes from lactic acid buildup: It's an often-quoted principle that the delayed onset muscle soreness (DOMS) you feel in the days after your workout is from lactic acid in your body. In fact, DOMS is a symptom of micro tears in the muscles that happen when you work out. Lactic acid does play a part in your workout, however, since it is the cause of that burning sensation you feel when working your muscles. It actually fuels muscles to help you work out longer, so pushing past that burning sensation will help you increase your strength and endurance.
3. If you stop exercising, your muscle turns into fat: Once you've got your workout routine down, you'll be surprised at how toned you feel. But something like a vacation or sickness can set your regimen back, sometimes leading to weight gain. While many people believe the weight gain is from muscles turning into fat, both tissues are completely different and can't convert from one to the other (similarly, there's no way to make muscles leaner, since they are already fat-free). Instead, building muscle helps burn fat, so when you have less of it, your metabolism rate will be lower.
Keep reading for two more muscle myths.
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