Health Claims

After eating a carb-heavy meal, people with more active brown fat burn about twice as much extra energy as people with less active brown fat, which might help with managing body weight.

Correlational

Leg extensions make the whole front of your thigh muscle grow evenly, while squats mainly make the middle part of a different thigh muscle grow.

Descriptive

Even if you work out the same amount and intensity, what exercise you pick can change which part of your muscle gets bigger.

Causal

Different leg exercises make different parts of your thigh muscles grow bigger—leg extensions grow all parts of one muscle, while squats mainly grow the middle part of another.

Causal

Even when people get tired, they still mostly stick to the tempo they planned—so training with specific timing (like slow lowers) is realistic and doable.

Descriptive

You can still build muscle and stay strong with lighter weights if you slow down the movement—this is especially helpful for seniors, injured people, or athletes taking a break from heavy lifting.

Descriptive

Rapidly pushing up a weight (like exploding upward in a squat) may make you stronger and faster than lifting the same weight slowly.

Descriptive

Slowing down the lowering part of a lift (like slowly lowering a dumbbell) makes your muscles more damaged and triggers more repair and growth than quickly lowering it.

Descriptive

How long your muscles are working during a lift matters just as much as how heavy the weight is for building muscle, burning energy, and improving nerve-muscle control.

Descriptive

Even if you lock your knees at the top of a squat, your thigh muscle still gets less oxygen during the exercise than when you're just standing still — but not as much as if you keep your knees bent.

Descriptive

If you keep your knees bent while squatting (no locking), your thigh muscle gets more oxygen-starved than if you lock your knees at the top — even if you do it for the same amount of time.

Descriptive

When you squat all the way down without locking your knees, your thigh muscle gets more oxygen-deprived than if you stop short and lock your knees — which might help build muscle.

Descriptive

Part of why protein makes you feel full is because your body burns more calories digesting it, but we still don’t know how much hormones in your gut are involved.

Descriptive

In the short term, meat and dairy make your body burn more calories after eating than plant proteins like beans or tofu, but after a while, both types work the same way.

Descriptive

Eating more protein while losing weight helps you lose fat instead of muscle and improves your blood sugar and cholesterol levels.

Descriptive

After losing weight, eating more protein helps you keep it off because it keeps you full, burns more calories during digestion, and helps you keep muscle instead of losing it.

Descriptive

Eating more protein makes you feel fuller for longer than eating the same amount of carbs or fat, which helps you eat less and manage your weight better.

Descriptive

If you're new to weight training, you can expect to build about 1.5 kg of muscle in the first couple of months, but after six months, the gains slow down a lot—after that, you might only add half to two and a half kilos of muscle per year, depending on your body and how long you've been training.

Quantitative

When muscles get bigger over time, it’s not because they’re just storing more water or sugar—those things don’t stick around. Instead, muscles grow mainly by adding more of the actual contractile parts that make them strong.

Causal

Even if you make your muscles feel that burning, swollen 'pump' feeling during a workout by boosting certain chemicals, it doesn't actually make your muscles grow bigger—studies show muscle growth doesn't happen just from that sensation.

Causal

Even if your body releases a lot more of the 'muscle-building' hormones after a workout, it doesn’t mean you’ll grow more muscle than someone whose hormone levels stay low—studies show both groups end up with the same muscle size.

Causal

When you lift weights, the pulling force on your muscles is what makes them grow bigger—not hormones or feeling tired. This force turns on internal signals that tell your muscles to make more protein and get larger over time.

Mechanistic

Whether you train with one joint (like leg extensions) or multiple joints (like squats), you get just as strong at the movement you train — but if you train a simple movement, you get a bit stronger at holding still too, compared to complex movements.

Quantitative

Beginners get the biggest strength boosts from lifting weights, but even they get way stronger at moving weights than at holding still — the gap between those two types of strength stays the same no matter how fit you are.

Quantitative