Caffeine decreases neuromuscular fatigue in the lumbar muscles – a randomized blind study

Abstract

Background Ergogenic evidence for caffeine is robust in sports and isolated limb tasks. Our objective was to evaluate a possible ergogenic effect on postural muscles, still unknown, through the Biering-Sorensens lumbar extension test. Methods A double-blind, controlled placebo, crossover study. Fifty-one healthy, physically inactive male subjects (18-25 years) with average body mass (BMI 18.5-24.9 kg/m2) were recruited. The subjects received oral caffeine (6 mg/kg) and saline (0.3%) in two cross-evaluations separated by one week. The primary outcome was the time in the Biering-Sorensen test after 1 hour of treatment. The secondary outcomes were peak lumbar extension force, rating of perceived exertion, EMGs median frequency and muscle recruitment of multifidus spinae and transversalis/interne oblique muscles, and cardiovascular variables (heart rate and blood pressure). Results 27 subjects were blindly treated with caffeine and saline. Caffeine was ergogenic during the Biering-Sorensen test. It increased lumbar extension time (d=0.34, P<0.05), but not peak force. The perception of effort decreased with caffeine (d=0.37, P<0.05). Caffeine increased muscle stimulation frequency (P<0.05) and recruitment (η²=0.49, P<0.05) of multifidus spinae. In the transversalis/interne oblique muscles, caffeine increased the median frequency (η² = 0.13, P<0.05) and the distribution of higher frequencies (P<0.05). Caffeine also increased muscle recruitment in the transversalis/interne oblique muscles (η²=0.94, P<0.05). Tachycardia and increased blood pressure at the lumbar test were higher in the caffeine condition (P<0.05). Conclusions Our results show that caffeine is ergogenic for postural muscles. Decreased RPE and improved muscle activity suggest central mechanisms of caffeine. Trial registration UTN U1111-1234-2079.

Exercise Attenuates Sickness Behavior And Protects Against Dopaminergic Impairment Induced By Neuroinflammation

“…First, the animals were divided into sedentary (SED) and exercise groups (RW). Running mice were housed in individual polypropylene cages (27 × 18 × 13 cm) equipped with RW (4½”, Super Pet, USA) to stimulate voluntary running [28, 39, 40]. Control SED animals were also isolated and had access to a “locked” RW (not spinning).…”

“…Running distance was measured every 24 hours at the same time (19:00 h). The free and locked wheels remained in the same location in the cage [28, 39, 40]. Wheels blockade reduces the environmental enrichment bias of running wheels, and, therefore, the effects observed derive from physical exercise only.…”