Forskning
October 10, 2011
The effect of physiological concentrations of caffeine on the power output of maximally and sub maximally stimulated mouse EDL (Fast) and soleus (slow) muscle
J Tallis et al, The effect of physiological concentrations of caffeine on the power output of maximally and sub maximally stimulated mouse EDL (Fast) and soleus (slow) muscle,Journal of Applied Physiology, 2011, article in press.
Abstract; ‘The ergogenic effects of caffeine in human exercise have been shown to improve endurance and anaerobic exercise performance. Previous work has demonstrated that 70ìM caffeine (physiological maximum) can directly increase mouse extensor digitorum longus (EDL) muscle power output (PO) in sprint like activity by 3%. Our study used the work loop technique on isolated mouse muscles to investigate whether the direct effect of 70μM caffeine on PO differed between: 1) maximally and sub maximally activated muscle; 2) relatively fast (EDL) and relatively slow (soleus) muscles; 3) caffeine concentrations. 70μM caffeine treatment resulted in significant improvements in PO in maximally and sub maximally activated EDL and Soleus (P <0.03 in all cases). For EDL the effects of caffeine were greatest when the lowest, submaximal, stimulation frequency was used (p<0.001). 140, 70 and 50μM caffeine treatments resulted in significant improvements in acute PO for both maximally activated EDL (3%) and soleus (6%) (P <0.023 in all cases), however there was no significant difference in effect between these concentrations (p>0.420 in all cases). Therefore, the ergogenic effects of caffeine on power output was higher in muscles with a slower fibre type (P <0.001). Treatment with 35μM caffeine failed to elicit any improvement in PO in either muscle (P >0.72 in both cases). Caffeine concentrations below the physiological maximum can directly potentiate skeletal muscle power output. This caffeine induced increase in force could provide similar benefit across a range of exercise intensities with greater gains likely in activities powered by slower muscle fibre type.’
