Browse evidence-based analysis of health-related claims and assertions
When doing a hip thrust with a barbell instead of a squat, the butt and back of the thighs light up more on muscle sensors during the same level of effort.
Descriptive
What makes someone strong right now isn’t the same as what makes them get stronger after training — your starting point doesn’t tell you how much you’ll improve.
Correlational
For the outer calf and deep calf muscle, it doesn’t seem to matter much whether you do straight-leg or seated calf raises — both work about the same.
Causal
When you get stronger holding a position (like pushing against a wall), your muscle size matters more — but when you’re moving (like kicking a ball), how hard you activate your muscles matters more than how big they are.
Even though the vastus intermedius is a deep thigh muscle you can't see, its fiber angle changes were linked to better leg strength during both pushing and lowering movements — it might be more important than it looks.
The type of leg exercise you do — whether it’s a leg press, leg extension, or calf raise — can change which part of your leg muscles grow bigger, and you can see the difference in just 8 weeks.
Men who started with a longer tendon lever arm and could already activate their thigh muscles better tended to get stronger in eccentric movements after training — their starting point mattered.
If you want to grow the inner part of your calf muscle, doing straight-leg calf raises might work better than seated ones.
When untrained men get stronger during dynamic leg extensions, the biggest factor is how much they can turn on their thigh muscles — bigger muscles and fiber angles help a little, but turning on the muscles harder matters most.
If you want to grow the outer part of your thigh (vastus lateralis), leg presses might be more effective than leg extensions.
If you want to grow the front part of your thigh muscle (rectus femoris), doing leg extensions might work better than doing leg presses.
When untrained men get stronger in a static leg press, the main reason is that their thigh muscle near the hip gets bigger and its fibers angle more, which helps push harder.
Even though people do more work and feel less burned out chemically with 5-minute breaks, their heart rate and how hard they feel they’re working is about the same as with 2-minute breaks.
With 5-minute breaks, people can keep pushing with nearly the same force in every set, but with 2-minute breaks, their force drops more and more with each set.
Quantitative
The idea that the order your body burns food (alcohol first, then protein, etc.) tells you which food makes you feel full first is not true — eating these foods in equal amounts doesn’t make you feel differently full.
Even though people do more work with 5-minute breaks, their muscles produce less lactic acid than with 2-minute breaks, meaning they’re not as burned out from chemical buildup.
After doing hard leg pushes with 5-minute breaks, people’s muscles stay stronger and more activated afterward than after 2-minute breaks, meaning they don’t get as tired.
Even though alcohol makes your body stop burning fat, it doesn’t stop your blood fat levels from rising — they go up just as much as if you ate a fatty meal.
When doing intense leg exercises with 5-minute breaks between sets, people can do more total work than with only 2-minute breaks, because their muscles recover better.
Even though alcohol, protein, carbs, and fat affect your metabolism differently, eating any of them in similar amounts doesn’t make you feel hungrier or fuller, or change how much you eat next.
When you eat a meal with a lot of alcohol, your body stops burning fat and makes less of the hormone that tells you you're full, more than when you eat the same calories from other foods.
Eating a meal high in alcohol makes your body burn more calories right after eating than eating the same number of calories from carbs or fat, and protein does it a little less.
Whether you squat deep or shallow, doing squats twice a week for 8 weeks makes young tennis players stronger and leaner—depth matters for how much, but doing squats at all is what gets the job done.
Deep squats help young tennis players lose more body fat than shallow squats—after 8 weeks, they lose about a third of their body fat, while shallow squats only help them lose 15%.