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How Heavy Should I Lift to Build Muscle

It’s time to get down and dirty. We know you’re here for one thing: muscle. So let’s not waste any more of your time with the basics, we’ll just cut straight to the answer: how heavy should I lift? 

The answer depends on what you want to achieve as well as what type of lifting regimen will best suit your needs. If you’re a beginner, it is recommended that you start by lifting weights lighter than 60% of your 1RM (one rep max). This will allow for an easier transition into strength training and help prevent injuries from overdoing it early on in the process.

When you hit the weights on your cross-training days, you probably think that the heavier you lift, the stronger you’ll get. And if you aren’t a fan of loading up the barbell, you may wonder if your workouts are actually working.

Good news: According to new research, you might not have to complete Arnold Schwarzenegger-level workouts in order to build muscle. As long as you go to failure—no matter the amount of weight you’re lifting—you’ll see results.

The 12-week study, published in the Journal of Strength & Conditioning Research, included 23 previously untrained women (ages 18 to 27) who were randomly split into two groups: Those who would be lifting at 30 percent of their one-rep max (low load) and those who would be lifting at 80 percent of their one-rep max (high load).

You’ll Torch More Body Fat

Build more muscle and you’ll keep your body burning fat all day long — that’s the science behind why lifting weights burns more fat than many other fitness modalities. (Here’s all the science behind why muscle helps you burn fat and calories.)

“Lifting weights can increase your lean body mass, which increases the number of overall calories you burn during the day,” says Jacque Crockford, C.S.C.S. and spokesperson for the American Council on Exercise. Burning extra calories post-workout plus building muscle? That’s the surefire way to get the body you want.

In recent research on overweight or obese adults (age 60 and over), the combination of a low-calorie diet and weight training resulted in greater fat loss than a combination of a low-calorie diet and walking workouts, according to a 2017 study published in the journal Obesity. The adults who walked instead of weight trained did lose a comparable amount of weight, but a significant portion of the weight loss included lean body mass. Meanwhile, the adults who did strength training maintained muscle mass while losing fat. 

This suggests that strength training is better at helping people lose belly fat compared with cardio because while aerobic exercise burns both fat and muscle, weight lifting burns almost exclusively fat.

On weeks 1, 5, and 12, participants completed either 30 percent or 80 percent of their one rep maxes for four different exercises: leg extension, seated military press, leg curl, and lat pulldown—3 sets of 8 to 10 reps. On weeks 2 through 4 and 6 through 7, they completed two sets of each exercise to failure. And on weeks 8 through 11, they completed three sets of each exercise to failure.

All exercises were done at either 30 percent or 80 percent of their one rep max. The high load group completed fewer reps to get to failure than the low load group.

The results? Regardless of which group participants were placed in, they all achieved similar—and significant—increases in upper- and lower-body strength. From week 1 to week 12, each exercise saw the following one rep max increase:

  • Leg extension: an average of 24 percent strength increase
  • Seated military press: an average of 14 percent strength increase
  • Leg curl: an average of 26 percent strength increase
  • Lat pulldown: an average of 13 percent strength increase

Additionally, there were no differences in body composition between the two groups either.

Is Weight Lifting An Automatic Path To Big, Bulky Muscles?

“When people say ‘bulky’ muscle they are usually referring to either more muscle than they want or like, or more often, someone that has a muscular physique but also has a significant amount of body-fat. 

It is very possible to structure a training and exercise program that does not result in either of these,” says Chris “Protein” Leach, an ISSA Certified Personal Trainer and NASM Certified Weight Loss and Nutrition Specialist.

When you lift weights, a large part of the stress is on the nervous system, not necessarily the muscles; heavier weights equals more signals from the brain to muscles. That means, without any other changes to your routine, lifting heavy weights will only make you stronger, not bigger.

When you lift heavier loads to failure, you still build muscle too, due to the specificity of the training weight and mechanical tension—or tension exerted on the muscle from the heavier weight, which leads to the recruitment of more muscle fibers during the lift—according to Dinyer.

“This subjects more of the muscle to the training stimulus, even though fewer repetitions are completed and the sets are shorter in duration. In addition, mechanical tension may increase the number of proteins in the muscle required for strength development,” she said.

The good news is, you can lift lighter and still get good results, but you still need to push yourself—getting to failure is key. You know you’re at failure when you can’t complete another rep while maintaining proper form.

As long as you are lifting to failure, the amount of weight you choose doesn’t matter so much. In fact, going lighter than you think you should might end up making you stronger in the long run.

Resistance training to failure at lighter loads is a viable option for individuals who desire to get stronger, but do not enjoy lifting heavy or prefer a muscular endurance approach to training,” Dinyer said.

How Diet Comes Into Play

There’s a reason that bodybuilders and weight lifters are so focused on their diets: bulking up depends on calories. “The total amount of food, or at least caloric intake, is one of the most relevant factors,” says Leach.

“Most people that the average person says looks ‘bulky’ are people that lift, but also have high body-fat, which is entirely a result of their nutrition.”

Diet is why a lot of men see a plateau in size and women don’t see the slimming results they want. Simply put: if you eat more than you burn, you’ll get bigger. In order to really start getting bigger, you need a diet to match that work in the gym.

You’ll Especially Lose Belly Fat

While it is true that you can’t spot reduce — your body is born with pre-conceived places it wants to store fat based on a slew of factors — a University of Alabama study found that the women who lifted weights lost more intra-abdominal fat (deep belly fat) than those who just did cardio. 

Burning more belly fat may also contribute to general weight loss from lifting weights. And the benefits of lifting weights don’t stop there. You’ll build a more defined muscular physique, but it also lessens your risk of diabetes, metabolic syndrome, and some cancers. (Not to mention, lifting heavy weights recruits your core, giving you an abs workout without even trying.)

Strength training may have a reputation of making women “bulk up,” but it’s not true. The more your weight comes from muscle (rather than fat) the leaner you’ll be. “In fact, body weight often goes up with strength training, but dress size goes down one or two sizes,” says Holly Perkins, C.S.C.S. founder of Women’s Strength Nation. 

Plus, it’s difficult for women to get body-builder huge. “Women produce about 5 to 10 percent the amount of testosterone men do, limiting our muscle-building potential when compared to men,” says Jen Sinkler, an Olympic lifting coach, kettlebell instructor, and author of Lift Weights Faster. To seriously gain size, you’d pretty much need to live in the weight room. (More proof: What Really Happens When Women Lift Heavy Weights)

Your Muscles Will Look More Defined

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Love the lean, defined muscles on super-fit ladies? “If women want more definition, they should lift heavier since they cannot get bigger muscles because of low testosterone levels,” says Jason Karp, an exercise physiologist and author. “So, lifting heavier has the potential to make women more defined.” (Seriously. Here’s why you can lift heavy and won’t bulk up.)

If you want more proof, watch this video with two-time Reebok CrossFit Games champion Annie Thorisdottir, who has a great body and certainly isn’t afraid to throw around heavy weights.

On Men Vs. Women

Along with physical appearance, strength training has amazing health benefits for both sexes —ladies, don’t be afraid of the weight room! A lot of women either shy away from the weight room or think that they need a completely different workout than a man.

While we’re guessing that the focus of womens’ workouts will differ—men and women store fat in different areas—that doesn’t mean that ladies should be using light weights to avoid bulking up.

(Pro tip: Leach noted that he gets a lot of requests from women wanting overall toning and shapely lower body; he recommends a program that focuses primarily on the lower body.)

Focus areas aside, all else stays the same between sexes. Men and women should both be utilizing bigger weights, proper form, and a clean diet.

For the women worried about getting bulky or huge from lifting big weights: thanks to hormones, you almost certainly won’t pack on muscle like a man.

Women don’t have the same amount of testosterone as men, so lifting weights doesn’t automatically equal muscle mass (aka gains). That testosterone difference means men will get bigger much faster.

For women, hormones are win/lose at the gym: strength training will help you tone, but you’ll have more trouble losing that last bit of fat.

You’ll Burn More Calories Than Cardio

Just sitting on your butt reading this, you’re burning calories — if you lift weights, that is.

You may burn more calories during your 1-hour cardio class than you would be lifting weights for an hour, but a study published in The Journal of Strength and Conditioning Research found that women who lifted weights burned an average of 100 more total calories during the 24 hours after their training session ended. 

Another study published in the International Journal of Sport Nutrition and Metabolism found that, following a 100-minute strength training session, young women’s basal metabolic rate spiked by 4.2 percent for 16 hours after the workout—burning about 60 more calories.

And the effect of this benefit of lifting weights is magnified when you increase the load, as explained in a study in the journal Medicine & Science in Sports & Exercise. 

Women who lifted more weight for fewer reps (85 percent of their max load for 8 reps) burned nearly twice as many calories during the two hours after their workout than when they did more reps with a lighter weight (45 percent of their max load for 15 reps). (Up next: 7 Common Muscle Myths, Busted.)

Why? Your muscle mass largely determines your resting metabolic rate — how many calories you burn by just living and breathing. “The more muscle you have, the more energy your body expends,” says Perkins. “Everything you do, from brushing your teeth to sleeping to checking Instagram, you’ll be burning more calories,” says Perkins.

Getting Toned And Lean

Shaping a lean, toned body isn’t an easy task, but the recipe is more straightforward than we sometimes think: lift big, do cardio, and eat healthy food. And yes, we said lift big.

“It’s a huge myth that lighter weights and higher reps will help with toning. The truth is that light weights with high reps will have little or no effect on body composition. Taking the dog for a walk or carrying groceries probably illicit a greater physiological response than pumping the three-pound dumbbells for 20 minutes,” says Leach.

“Sets need to be taken within a few reps of maximum capacity to be effective. In other words, it needs to feel like you can’t do very many, if any, more.”

You need to be strong to be lean, and weight lifting is your ticket to success here. If you feel like you’re too big, it’s almost certainly an issue with diet or the amount of cardio you’re doing.

You’ll Strengthen Your Bones

Weight lifting doesn’t only train your muscles; it trains your bones. When you perform a curl, for example, your muscles tug on your arm’s bones. The cells within those bones react by creating new bone cells, says Perkins. Over time, your bones become stronger and denser.

The key to this one is consistency, as research has shown that lifting heavy weights over time not only maintains bone mass but can even build new bone, especially in the high-risk group of post-menopausal women. (Psst…Yoga has some bone-strengthening benefits too.)

Strength, Not Mass

If a toned look is your goal, put a focus on strength. Cardio is going to help (and it’s good for your heart), but doing more and more cardio won’t compensate for a poor diet, and it won’t shape your muscles like lifting does.

A lean body is just a strong one with low body fat—so you need that time in the weight room if you’re going to achieve your goals.

You’ll Get Stronger

Lifting lighter weights for more reps is great for building muscle endurance, but if you want to increase your strength, increasing your weight load is key. Add compound exercises such as squats, deadlifts, and rows to your heavy weights and you’ll be amazed at how fast you’ll build strength. (Here’s what really counts as lifting heavy and how often you should do it.)

This particular benefit of lifting weights has a big payoff. Everyday activities (carrying groceries, pushing open a heavy door, hoisting a kid) will be easier—and you’ll feel like an unstoppable powerhouse, too.

You’ll Feel Empowered

Throwing around some serious iron doesn’t just empower people in the movies. Lifting heavier weights — and building strength as a result — comes with a big self-esteem boost, and this might just be the biggest benefit of lifting weights above all other aesthetic factors. Your strength will not only show in your lean, toned body, but also in your attitude. (See: 18 Ways Weight Lifting Will Change Your Life.)

“Strength has a funny way of bleeding into all areas of your life, in the gym and out,” says Sinkler. By constantly challenging yourself to do things you never thought possible, your confidence grows. “Weight lifting empowers you,” she says.

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