It’s estimated that there are over 2+ million scientific papers published each year, and this firehose only seems to intensify.

Even if you narrow your focus to fitness research, it would take several lifetimes to unravel the hairball of studies on nutrition, training, supplementation, and related fields.

This is why my team and I spend thousands of hours each year dissecting and describing scientific studies in articles, podcasts, and books and using the results to formulate our 100% all-natural sports supplements and inform our coaching services. 

And while the principles of proper eating and exercising are simple and somewhat immutable, reviewing new research can reinforce or reshape how we eat, train, and live for the better. 

Thus, each week, I’m going to share three scientific studies on diet, exercise, supplementation, mindset, and lifestyle that will help you gain muscle and strength, lose fat, perform and feel better, live longer, and get and stay healthier. 

This week, you’ll learn how heavy weightlifting boosts endurance, how NSAIDs may hinder muscle growth, and how fidgeting helps you burn calories.

Heavy weightlifting boosts endurance performance.

Source: “Effects of Strength Training on Olympic Time-Based Sport Performance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials” published on November 1, 2019 in The International Journal of Sports Physiology and Performance.

Research has been heaping up for years showing that strength training can boost performance in sports that involve sprinting, jumping, throwing, punching, kicking, wrestling, and swinging (a bat or club, for example).

While it’s considered axiomatic and obvious that lifting weights improves performance in sports that hinge on power and strength, it’s just as often assumed that it’s either benign or even detrimental for endurance athletes. 

This shiboleth is starting to crumble, though, as more and more studies show that lifting weights also helps you move farther and faster. For instance, several studies have found that lifting weights improves running and cycling efficiency, rowing endurance and power, and swimming stroke rate and speed.

In this study, scientists at the Singapore Sport Institute reviewed 25 randomized controlled trials (the gold standard of scientific studies) involving 568 teenage athletes who were either well- or recreationally-trained.

The results showed that the only strength training protocol to have a positive effect on endurance performance was heavy weightlifting, which had a small-to-moderate positive effect.

(The results actually showed heavy weightlifting had a moderately positive effect, but this positive result was propped up by two studies which found it far more beneficial than the rest. If you removed these outliers from the analysis, the effect was less pronounced but still significant.) 

These benefits were only statistically significant in the most experienced athletes, which is puzzling at first but has several possible explanations. 

On the one hand, experienced athletes are generally less responsive to training and make smaller improvements than unseasoned athletes, who typically adapt faster. On the other hand, it’s also possible that beginner endurance athletes still had so much room for improvement—newbie gains—that they were better off simply doing more of their specific endurance sports than lifting weights.

In other words, the more experienced athletes had probably squeezed most of the gains that were available to them from pure endurance training, and were able to profit more from the benefits of weightlifting than newbies.

Thus, you could argue that beginner endurance athletes don’t need to lift weights from a pure performance standpoint. As the researchers astutely pointed out, though, weightlifting may indirectly improve performance (and health, of course) by making the athletes more resilient, less likely to get injured, and thus able to train more consistently over time. 

This study also found that plyometric training didn’t improve endurance performance, despite increasing the athletes’ ability to generate power. Several other meta-analyses and reviews have shown the opposite—that plyometric training does improve endurance performance—so it’s possible there may be some benefit. (The whole body of evidence surrounding plyometric training for endurance athletes is murky and beyond the scope of this article.) 

At this point you may be wondering, how much does strength training improve endurance performance, and what’s the best kind of strength training program for this goal? 

According to the researchers in this study, you can think of weightlifting’s impact on endurance performance like this:

Let’s assume that an athlete is ranked 50th in the world’s top 100. After following a weightlifting program, you can expect that the athlete will move up to rank 24th (if you include all 25 of the studies in this meta-analysis) or 32nd (if you remove the 2 studies that reported extreme results).

A significant bump in performance—and this isn’t counting the many health benefits and injury resistance that you can expect from strength training as well. 

As for how much weightlifting you should do, here’s what the researchers recommend for endurance athletes:

  • Lift weights 2-to-3 times per week.
  • Do 1-to-6 sets per major muscle group per week.
  • Train in the 3-to-12 rep range.

Basically, just a traditional strength training program with slightly less frequency and volume.  

And if you’d like even more specific advice about how often you should train, what exercises you should do, and for how many sets and reps to reach your health and fitness goals, take the Legion Strength Training Quiz, and in less than a minute, you’ll know the perfect strength training program for you. Click here to check it out.

TL;DR: Heavy weightlifting improves performance in well-trained endurance athletes, and it probably improves injury resistance and overall health in all endurance athletes.

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NSAIDs may stymie muscle and strength gain.

Source: “High-doses of anti-inflammatory drugs compromise muscle strength and hypertrophic adaptations to resistance training in young adults” published on September 16, 2017 in Acta Physiologica.

Many athletes look at NSAIDs (non-steroidal anti-inflammatories) the same way they look at their morning coffee—a harmless pharmacological boost that helps them get through the day.

And while you aren’t technically supposed to take these medicines daily, active folks frequently pop these pills while recovering from aches and pains or even preemptively before engaging in any kind of strenuous exercise.

Are these painkillers all profit and no loss, though? 

One of the most common NSAIDs is ibuprofen, which works by inhibiting cyclooxygenase (COX)—an enzyme that plays a role in controlling inflammation and pain. 

However, COX enzymes are also involved in muscle building, which led some scientists to believe that taking NSAIDs might stymie muscle growth.

To test this theory, researchers at Karolinska University Hospital conducted a study investigating the effect of taking a high dose of ibuprofen or a low dose of aspirin (which works through a slightly different mechanism and shouldn’t negatively affect muscle growth) on muscle and strength gain in young men and women.

The researchers split 17 men and 14 women with at least 6 months of weightlifting experience into an ibuprofen group and an aspirin group.

The ibuprofen group took 1,200 mg of ibuprofen per day, split into 3 evenly spaced 400-mg doses, which is the maximum recommended over-the-counter daily dose (although some folks with injuries take even more than this). The aspirin group took one 75-mg dose of aspirin per day with breakfast. 

Both groups completed 20 training sessions over 8 weeks. In each training session, the participants trained one leg with 4 sets of 8-to-12 reps on a traditional leg extension machine and the other with 4 sets of 7 reps on a leg extension machine geared toward increasing power.

Throughout the study, both groups lifted about the same total amount of weight on average (~1,175 lb versus ~1,194 lb for the ibuprofen and aspirin group, respectively).

The main finding was that the group taking ibuprofen gained significantly less muscle in their legs than the group taking aspirin. Specifically, average muscle growth increased 3.7% in the ibuprofen group and 7.5% in the aspirin group.

What’s more, all of the participants increased various measures of strength in both legs, but the gains tended to be slightly higher in the aspirin group. The aspirin group also increased power more than the ibuprofen group (29% vs. 20%). 

Finally, blood test results showed that the aspirin group increased levels of interleukin-6, a marker of inflammation that also plays a role in hypertrophy, 1.5-fold from baseline, whereas the ibuprofen group decreased levels 0.8-fold from baseline.

These results are in line with several other studies that have already demonstrated the same thing: regularly taking large doses of NSAIDs may be detrimental to muscle gain. 

As such, you should probably avoid long-term NSAID use if you want to maximize your athletic performance and body composition.

That said, it probably isn’t something you need to worry about if you take smaller doses for a brief period of time. Previous research shows that taking 400 mg daily for 6 weeks wasn’t enough to interfere with muscle gain. 

It’s also worth keeping in mind that ibuprofen doesn’t completely nullify the benefits of weightlifting or physical activity in general. In the main, if you need to take some ibuprofen or another NSAID to get through a few workouts while you recover from an injury, it’s probably worth it. Just don’t make it a habit. 

One final reason long-term NSAID use probably isn’t a good idea is that NSAIDs mask pain and allow you to train harder when you’re injured, but they don’t “fix” the underlying injury. 

For example, let’s say your shoulder aches when you bench press—a common repetitive stress injury. Many people’s first reaction is to take some painkillers and get back at it, which is one of the worst things you could do.

Overuse injuries are caused by doing too much too quickly, and pain is a signal to tap the brakes and let your body heal. In this case, taking ibuprofen, NSAIDs, or other painkillers simply allows you to dig yourself deeper into a hole until the pain (and damage) gets so bad you may have to quit pressing altogether to heal your shoulder.

A better solution is to heal before you train hard. Or, better yet, avoid injury altogether by following a well-designed training program that includes the right number of weekly sets to help you strengthen your entire body without wearing yourself to a frazzle, as I explain how to do in my fitness books Bigger Leaner Stronger for men and Thinner Leaner Stronger for women. 

TL;DR: Taking large doses of NSAIDs every day for several weeks hinders muscle growth, but probably isn’t worth worrying about if you take a smaller dose infrequently. 

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Fidgeting helps you burn a lot more calories than you might think. 

Source: “Energy expenditure of nonexercise activity” published on May 18, 2000 in The American Journal of Clinical Nutrition.

When most people think of exercise for weight loss, they think it needs to be intense or prolonged: hill sprints, HIIT workouts, long runs or bike rides, and so on.

The logic here isn’t wrong: If you control your calorie intake (how much you eat), the more calories you burn through exercise, the more weight you’ll lose. And the more intense or longer your workouts, the more calories you burn, and the faster you lose weight. 

It’s not the only way to skin this cat, though.

If all physical activity burns calories, couldn’t you get similar weight loss benefits by doing lots of relatively easy, short bouts of activity throughout the day? 

The technical term for this sporadic, low-intensity activity is non-exercise activity thermogenesis (NEAT), which includes all of the movements you make throughout the day that aren’t formal exercise. This includes things like fidgeting at your desk, pacing around the room while you talk on the phone, and walking from your car to the office.

How much can NEAT help you lose weight, though? 

That’s what scientists from the Mayo Clinic and Mayo Foundation wanted to find out when they had 24 people (17 women and 7 men) of varying weights perform a variety of activities that represent eight of the most common kinds of NEAT:

  1. Lying down motionless (the scientists had the participants do this for 1 hour and used the results as a baseline to compare the other activities to).
  2. Sitting motionless in a chair with their arms and legs supported.
  3. Sitting while fidgeting however they wanted.
  4. Standing motionless.
  5. Standing while fidgeting however they wanted.
  6. Walking on a treadmill at 1, 2, and 3 miles per hour. This was to emulate the spontaneous walking we do every day (walking to the bathroom, pacing back and forth while talking on the phone, and taking the stairs, for example). Some people also walk faster than others, which is why they measured three different speeds.

The researchers used a method called indirect calorimetry to measure calorie expenditure during each activity. This tool measures the mixture of gases that people exhale, and it’s one of the most reliable ways to measure calorie burning in a lab.

Here’s a graph showing how many calories the participants burned on average doing each activity:

Calories Burned During Non-Exercise Activity Thermogenesis

There are four main takeaways from these results.

First, standing while fidgeting increased metabolic rate by 100% versus lying down. In other words, basically any kind of activity burns a boatload more calories than vegetating in a chair. For instance, another study found that people who flip through a book instead of sitting motionless increased their metabolic rate by 30%. 

Second, how much you fidget plays a larger role in how many calories you burn than whether or not you’re sitting or standing. Standing motionless only burned about 8% more calories than sitting motionless, whereas sitting while fidgeting burned 25% more calories than standing motionless. Of course, standing while fidgeting burned even more calories, but at that point you might as well just go for a walk.

(This is another reason standing desks don’t help you burn as many calories as many people think, and why sitting isn’t as bad as it’s often made out to be).

The fly in the ointment here is that how much you fidget seems to be largely genetic. Thus, if you’re in the “non-fidgeting” camp, working while standing is probably a more reliable way to burn calories.

Third, walking just a little faster burns more calories than most people realize. For example, bumping your walking speed from 2 to 3 mph burns an extra 100 calories per hour. That’s easily doable for most people.

Finally, while everyone burned more calories by standing, fidgeting, and moving, it was the heaviest people who benefited the most from NEAT. This stands to reason, too, since it takes more energy to move a heavier body. And this means that overweight and obese people may have the most to gain from increasing their levels of NEAT.

If you’re looking for ways to increase your energy expenditure that don’t involve formal workouts, here’s what I recommend:

  • If you sit for long periods each day and aren’t prone to fidgeting, try to work while standing. When you get tired, take a seat, but try to gradually increase the time you spend on your feet each day (within reason).
  • Spend 20-to-30 minutes per day walking as briskly as you can. Use this time to talk on the phone, listen to a podcast or audiobook, or even answer email.
  • Don’t sit when you can stand.
  • Don’t stand still when you can move. For example, pace back and forth while you brush your teeth.
  • Don’t drive or take an elevator or escalator when you can walk.

Of course, all of this will be for naught if you aren’t also controlling your calorie intake.

And if you’d like specific advice about how many calories, how much of each macronutrient, and which foods you should eat to lose weight, take the Legion Diet Quiz, and in less than a minute, you’ll know exactly what diet is right for you. Click here to check it out.

TL;DR: You can burn as many or more calories by fidgeting, walking, and standing whenever possible throughout the day than from formal exercise.

+ Scientific References