Browse evidence-based analysis of health-related claims and assertions
Even after a super hard workout, the body’s baseline testosterone level doesn’t stay high the next day — it goes back to normal quickly.
Quantitative
After doing barbell chest presses, guys felt less ready to train again—even two days later—than after using dumbbells or a machine, meaning they needed an extra day to feel recovered.
Causal
The more the thigh swells after a workout, the more the MGF repair protein increases — suggesting MGF might be triggered by physical stretching or swelling in the muscle.
Correlational
The tools used to measure muscle size and strength were very consistent and accurate, so the results can be trusted.
In trained men, when one muscle repair protein (IGF-IEa) goes up after a workout, the other one (MGF) tends to go up too — they seem to work together.
No matter which chest press they used, the guys completed almost exactly the same number of reps in every set—showing they pushed just as hard regardless of equipment.
Even though testosterone levels go up during a heavy workout, the muscle’s testosterone receptors don’t change in number two days later in trained men.
Descriptive
When using dumbbells, guys had to use lighter weights per rep—about 18% less than with a barbell—to complete the same number of reps and total work.
After a heavy leg workout, men report their legs feeling very sore — about 3 out of 5 on a pain scale — and it lasts for at least two days.
We know muscles stretch less the second time you do a tough workout, but we don’t yet know why that happens.
Even though guys lifted less weight per rep with dumbbells, they did more reps to make up for it, so the total weight lifted ended up being about the same for everyone.
After the second tough arm workout, blood markers of muscle damage tend to be lower, but the difference isn't strong enough to be sure it's real.
After a tough leg workout, a blood marker of muscle damage (CK) spikes by more than 1.5 times and stays high for two days, showing the muscles are still healing.
After a tough chest workout, your ability to push your arm across your chest comes back fully within three days, no matter if you used a machine, barbell, or dumbbells.
The first time you stretch your biceps in each workout, it stretches the same amount—even if the second workout causes less damage overall.
After a heavy leg workout, the thigh muscles get noticeably thicker due to swelling, and this lasts for at least two days.
Even after a super hard chest workout, the size of the triceps muscles goes back to normal within a day—meaning the workout didn’t actually tear them up much.
During a tough leg workout, testosterone levels spike temporarily, but they go back to normal by the next day and don’t stay high.
People push just as hard during the second workout as the first, even though they feel less sore and recover faster.
No matter which type of chest press you do—machine, barbell, or dumbbells—you’ll feel about the same level of soreness in your chest muscles after a hard workout, and it’ll go away at the same rate.
How much your biceps stretch during your first hard workout tells you how sore and weak you’ll feel the next day—but not how much enzyme leaks into your blood.
After a heavy leg workout, men can't push as hard with their legs for at least two days — even though they're trained, their strength is still a little weaker.
After doing a barbell chest workout, guys felt way more tired and less recovered than after using dumbbells or a machine—even two days later—suggesting barbells leave you feeling more drained.
The more the biceps stretched during the first workout, the more 'swelling' showed up on the ultrasound scan afterward.