For how we live.
Heavy loads drove significantly greater one-rep-max strength than light loads in a 21-study meta-analysis, while size gains were similar. A trial found strength maxed out at low volume, the main driver of growth.
Weekly scans found thigh muscle grew measurably within about three to four weeks, once early swelling was discounted. A biopsy study found real fibre growth appeared only later, at ten weeks.
A 2016 meta-analysis found training a muscle twice a week beat once. A larger 2019 update found the edge vanished once weekly volume was equated — leaving frequency as a scheduling choice.
A meta-regression found each extra weekly set added about 0.37% more growth, a graded but flattening curve. A separate trial found strength barely moved between one, three and five sets.
Sore muscles signal unaccustomed or eccentric effort, not how much you gained. In one 10-week study, peak muscle damage was unrelated to hypertrophy; growth tracked the later, calmer weeks.
In 25,241 non-exercisers, three brief daily bursts of vigorous activity tracked with markedly lower mortality. A small trial found stair-climbing 'snacks' raised fitness. The catch: they must be genuinely vigorous.
Training light loads with a limb cuff grows muscle about as well as heavy lifting, trials show. For maximal strength the evidence is mixed, and heavy weights may still edge it.
A 2024 meta-regression found strength gains barely track how close you stop to failure, while muscle growth rises the nearer you get. Two trials put the size gap close to zero.
A meta-analysis of 8,459 athletes found programmes with the exercise cut hamstring injuries by about half. In elite football, where the injury keeps rising, most squads leave it out.
Guidelines and trial evidence point to a target, not a tally: work each muscle group about twice a week and match recovery to effort. Training something every day is not, by itself, harmful.
A small double-blind trial found a single 5.5 mg/kg dose lifted sprint power for hours, alongside higher noradrenaline and lower perceived effort — but it was 12 people, mostly men.
Trials measuring it are small but consistent: nasal breathing lowers peak oxygen uptake and feels harder at intensity. The interesting findings sit at submaximal effort, not maximal.
The famous Stanford basketball study had eleven players and no control group. Fifteen years on, sleep extension is still the best-supported sleep intervention in sport, and still barely studied.
A ten-season analysis of 3,750 matches quantifies the load argument footballers have been making. It also states plainly what it cannot show: anything about injury.
Twenty experts scored three language models on ten common questions. One model cleared the content validity bar on both topics; another scored zero on jet lag.
The first large replication project in the field found effect sizes shrank substantially on repeat, and reports that many original authors declined to engage with the attempt.