Effect of caffeine on maximal strength and power in élite male athletes.

Abstract

Computerized testing of 20 élite male athletes was performed to determine the effect of 7 mg kg-1 caffeine on strength and power of the knee extensors and flexors. Subjects received counterbalanced administrations of either caffeine or a placebo on two separate occasions. Peak torque (T) was measured for knee extension (ET) and flexion (FT) at angular velocities of 30 degrees, 150 degrees and 300 degrees s-1. Additionally, performance for the first 125 ms (TAE) and power (W) were recorded during 300 degrees s-1. Testing sessions were held 1 week apart, at which time the placebo/caffeine administration was reversed. A 2 x 2 repeated measures analysis of variance supplemented with a Neuman-Keuls post hoc test showed the following--significant caffeine-related increases (P < 0.05) for ET at 30 degrees s-1, ET at 300 degrees s-1, and ETAE, and EW at 300 degrees s-1. Dependent t-tests performed for pre- to post-test means showed significant changes for the caffeine group in ET at 30 degrees s-1, FT at 30 degrees s-1, FT at 150 degrees s-1, ET at 300 degrees s-1, FT at 300 degrees s-1, E and FTAE, and EW at 300 degrees s-1. No significant effects were found for the placebo trial in any variable. It was concluded that caffeine can favourably affect some strength parameters in highly resistance-trained males. However, differences in subject fibre type, motivation and caffeine sensitivity need to be elucidated.

Caffeine improves neuromuscular function during maximal dynamic exercise

“…[16][17][18] Findings have suggested direct effects on muscle excitationcontraction coupling and motor unit recruitment, which are independent from those related to metabolic efficiency. [18][19][20] Unfortunately, most of the aforementioned studies have focused on maximal isometric strength, whereas the effect of caffeine on neuromuscular function during dynamic contractions at different speeds has not been investigated thoroughly.…”

Caffeine Use in Sports: Considerations for the Athlete

“…possibly because of the limited number of investigations and different protocols used (3,9,27,33,35,36,56,64).…”

“…In sprint and power events that rely mainly on the phosphogen system (#10 seconds), caffeine improved peak power output, speed, and isokinetic strength (3,36,56); however, in events that heavily rely on the glycolytic system (15 seconds to 3 minutes), no improvements were found with caffeine use, and in fact, it may have been detrimental to performance during repeated bouts of exercise (27,64). One study showed a 7% increase of peak power output during 6-second Wingate testing with consumption of 250 mg of caffeine (3), whereas another recent study showed improvements of intermittent sprint ability (during 4-second sprints) in soccer players when 6 mgÁkg 21 of caffeine was ingested (56).…”

Efecto del consumo agudo de cafeína sobre la fuerza máxima y los niveles de lactato en sangre en jóvenes sedentarios: Ensayo clínico aleatorizado

“…Estudios concluyen que la cafeína a dosis pequeñas no ejerce ningún efecto ergogénico sobre la función muscular en condiciones anaeróbicas 19 ; mientras en otro estudio se encuentra que a una dosis de 7 mg kg-1 la fuerza aumenta por la ingestión de cafeína 21 , a dosis de 6mg/Kg el aumento en la fuerza máxima es de 3,5% sin cambios en el reflejo H, concluyendo los autores que la cafeína actúa tanto periféricamente, como de forma supraespinal 18 . En otro estudio la fuerza máxima se incrementó en un 3,8% 22 y finalmente otro estudio encontró a una dosis de 6 mg/Kg un cambio en la fuerza equivalente al 17% y concluyen que el efecto de la cafeína esta sobre la reducción de la sensación de fuerza 23 .…”