Taking 4 mg of caffeine per kilogram of body weight, whether in gum or pill form, increases the maximum strength and power output during bench press and squat exercises in men who regularly train with weights, compared to taking a placebo.

For men who regularly train with weights, consuming 4 mg of caffeine per kilogram of body weight through chewing gum has the same effect on strength and power during bench press and squat exercises as taking the same dose in capsule form.

Taking caffeine before lifting heavy weights can increase the power generated during exercises like the back squat and bench press, with the largest gains occurring when lifting at 75–90% of maximum capacity.

Taking a dose of 6 mg of caffeine per kilogram of body weight has almost no meaningful impact on how much weight a young man who rarely consumes caffeine can lift in a single repetition of bench press or squat, even if the change is statistically detectable.

Taking 6 milligrams of caffeine per kilogram of body weight before a workout can increase the number of repetitions a person can perform to failure during bench press and squat exercises at 70% of their maximum strength, based on measured effect sizes in young men who rarely consume caffeine.

In young men who rarely consume caffeine, performance on a one-rep max bench press test improves even when they take a sugar pill instead of caffeine, suggesting that expectations or psychological factors can enhance strength output.