Caffeine increases endurance and attenuates force sensation during submaximal isometric contractions
| Autor: | C. J. Plaskett, E. Cafarelli |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Adult
Male Physiology Neuromuscular transmission Ergogenic Effects Isometric exercise Electromyography law.invention chemistry.chemical_compound Randomized controlled trial law Caffeine Isometric Contraction Physiology (medical) Sensation Humans Medicine Muscle Skeletal medicine.diagnostic_test business.industry Hemodynamics Electric Stimulation Electrophysiology chemistry Anesthesia Muscle Fatigue Physical Endurance Central Nervous System Stimulants business |
| Zdroj: | Journal of Applied Physiology. 91:1535-1544 |
| ISSN: | 1522-1601 8750-7587 |
| Popis: | Caffeine has known ergogenic effects, some of which have been observed during submaximal isometric contractions. We used 15 subjects in a randomized, double-blind, repeated-measures experiment to determine caffeine's ergogenic effects on neuromuscular variables that would contribute to increased endurance capacity. Subjects performed repeated submaximal (50% maximal voluntary contraction) isometric contractions of the right quadriceps to the limit of endurance (Tlim) 1 h after oral caffeine administration (6 mg/kg). Time to reach Tlim increased by 17 ± 5.25% ( P < 0.02) after caffeine administration compared with the placebo trial. The changes in contractile properties, motor unit activation, and M-wave amplitude that occurred as the quadriceps reached Tlim could not account for the prolonged performance after caffeine ingestion. In a separate experiment with the same subjects, we used a constant-sensation technique to determine whether caffeine influenced force sensation during 100 s of an isometric contraction of the quadriceps. The results of this experiment showed that caffeine reduced force sensation during the first 10–20 s of the contraction. The rapidity of this effect suggests that caffeine exerts its effects neurally. Based on these data, the caffeine-induced increase in Tlim may have been caused by a willingness to maintain near-maximal activation longer because of alterations in muscle sensory processes. |
| Databáze: | OpenAIRE |
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