The Claim

Ingesting 6 mg/kg of caffeine 60 minutes before morning lower-body squat exercise at 25%, 50%, and 75% of one-repetition maximum increases propulsive velocity in resistance-trained males, while having no significant effect on propulsive velocity during bench press or squat exercises performed in the afternoon.

Source: Improvements on neuromuscular performance with caffeine ingestion depend on the time-of-day.

What the research says

Supports is higher

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

Supports
48score
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.

Cause and effect
1 study reviewed
In plain English

Taking 6 mg of caffeine per kilogram of body weight one hour before morning squat workouts increases how fast a person can push during squats at moderate to heavy weights, but does not change speed during bench presses or squats done in the afternoon.

See the scientific wording

Ingesting 6 mg/kg of caffeine 60 minutes before exercise increases propulsive velocity during lower-body squats at 25%, 50%, and 75% of one-repetition maximum in resistance-trained males when performed in the morning, but has no significant effect on velocity during bench press or squat exercises performed in the afternoon.

Why this might work

Caffeine blocks signals that slow down nerve and muscle activity, making the brain send stronger signals to leg muscles and making the muscles contract faster. This effect is strongest in the morning when the body naturally performs slower, and it only happens in leg movements, not arm movements.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Improvements on neuromuscular performance with caffeine ingestion depend on the time-of-day.

    Taking caffeine before morning weightlifting helps men lift their legs faster during squats, but taking it in the afternoon doesn’t help at all. The study proves this happens specifically with leg exercises in the morning.

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

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.