Browse evidence-based analysis of health-related claims and assertions
Lifting weights twice a week for six weeks — whether using heavier or lighter weights — helps young, healthy guys build leg muscle just about the same amount, compared to not training at all.
Lifting weights twice a week for six weeks—whether doing fewer heavy reps or more lighter ones—can help young guys' muscles use oxygen better, which means their muscles may get more efficient at producing energy.
A new math method for combining study results might work well whether there are lots of studies or just a few, while older methods tend to struggle when there aren't many studies.
Some math methods used to combine study results might work better or worse depending on how many studies there are and how many people are in each one — this could help us figure out when those methods are trustworthy.
There's a new way to combine study results that doesn't assume the data follows a normal bell curve, which might make the final answer more trustworthy—especially when there aren't many studies or the data looks messy.
Even the best ways we have to fix trust between people and robots don't work very well — trust doesn't fully come back after it's broken.
When robots mess up, saying sorry and explaining what went wrong helps people trust them again better than other ways—being honest and owning the mistake really matters.
When robots mess up, saying sorry or explaining what went wrong works better than other fixes to get people to trust them again — but it still doesn’t work perfectly.
An old but popular way of combining study results isn't as good as some newer methods when it comes to accuracy in computer simulations that fix common measurement errors.
This math method for combining study results seems to give slightly more accurate answers than other similar methods when figuring out the true effect across many studies.
Some math methods for combining study results work better than others when trying to understand how much results vary — ones that adjust for more uncertainty give clearer answers, according to computer simulations in psychology research.
Random-effects meta-analysis is better than fixed-effect at guessing the true average result across different psychology and management studies, especially when fixing common data problems.
People who get stronger on one lift tend to get stronger on others too—so some people just respond better to training overall.
If you're someone who's been lifting weights for a while, doing the same amount of heavy training over 9 weeks will make your thigh muscles grow by about half a centimeter — whether you spread your workouts over 2 or 4 days a week.
If you're already fit, you might get stronger faster on machines you're not used to, even if they're simpler, compared to the free-weight exercises you've done a lot before — as long as you're doing the same amount and intensity of training.
If you're already fit, you might get stronger faster using gym machines like the chest press than doing classic lifts like squats or bench press — at least over 9 weeks — maybe because you're already used to the free weights.
If you're someone who's been lifting weights for a while, splitting your workouts into 2 days a week works just as well as doing them 4 times a week — as long as you're doing the same total amount of exercise over time.
Knowing how the biceps muscle can vary from person to person helps doctors spot nerve or blood vessel problems and avoid mistakes during arm surgery.
Sometimes people have extra muscle parts in their upper arm, and that can squeeze nerves or blood vessels or change how nerves are shaped — this might make surgeries or diagnosing arm problems trickier.
Someone was found to have a rare extra-headed bicep muscle in just one arm — something never seen before — during a regular anatomy class dissection.
The main chest muscle's tendon has two layers—one in front and one in back—and that might affect how it tears and how doctors fix it in surgery.
Your chest muscle has two parts—one on top near your collarbone and one lower near your breastbone—and because they work a bit separately, it might affect how doctors fix injuries and how well you heal.
If experienced guys do more sets of squats in one workout—like 5 or 6 instead of 2 or 3—they’ll feel more tired during that session, even if their total weekly workout volume stays the same.
If you're a guy who's been lifting weights for a while, doing either 2 or 4 workouts per week for each muscle can boost your strength by about 8–11% in just 8 weeks—as long as you do the same total amount of work overall.