The Claim

In female handball players aged 18–19 with low habitual caffeine consumption, evening ingestion of 3 mg/kg or 6 mg/kg of caffeine does not improve short-term maximal physical performance in countermovement jumps, agility, or repeated sprints and is associated with a significantly higher incidence of insomnia and headaches.

Source: Effects of Different Caffeine Dosages on Maximal Physical Performance and Potential Side Effects in Low-Consumer Female Athletes: Morning vs. Evening Administration

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
68score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

In young female handball players who rarely consume caffeine, taking 3 or 6 mg of caffeine per kilogram of body weight in the evening does not improve their performance in jumping, sprinting, or agility tests and increases the likelihood of insomnia and headaches.

See the scientific wording

In low-caffeine-consuming female handball players aged 18–19, evening ingestion of 3 mg/kg or 6 mg/kg of caffeine does not improve short-term maximal physical performance in countermovement jumps, agility, or repeated sprints, and is associated with a significantly higher incidence of side effects, particularly insomnia and headaches.

Why this might work

Caffeine blocks sleep-promoting signals in the brain, which keeps the mind alert at night and prevents restful sleep, but does not make the muscles stronger or faster during evening exercise. The same blockage that causes trouble sleeping also prevents the brain from boosting muscle power when it is naturally less active in the evening.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Effects of Different Caffeine Dosages on Maximal Physical Performance and Potential Side Effects in Low-Consumer Female Athletes: Morning vs. Evening Administration

    For young female athletes who don’t usually drink caffeine, taking it in the evening doesn’t help them jump higher, run faster, or change direction quicker—but it does make them more likely to have trouble sleeping or get headaches.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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