The efficacy of caffeine ingestion in enhancing aerobic performance is well established. The evidence for caffeine's effects on resistance exercise is mixed and has not fully examined the associated psychological and psychophysiological changes. This study examined acute effects of ingesting a caffeine-containing energy drink on repetitions to failure, rating of perceived exertion (RPE) and readiness to invest physical (RTIPE) and mental (RTIME) effort during resistance exercise to failure. Thirteen resistance trained males took part in this double-blind, randomized cross-over experimental study whereby they ingested a caffeinated (179mg) energy drink or placebo solution 60mins before completing a bout of resistance exercise comprising of bench press, deadlift, prone row and back squat exercise to failure at an intensity of 60% 1 repetition maximum. Experimental conditions were separated by at least 48hours. Participants completed significantly greater repetitions to failure, irrespective of exercise, in the energy drink condition (p = .015). RPE was significantly higher in the placebo condition (p = .02) and was significantly higher during lower body exercises compared to upper body exercises irrespective of substance ingested (p = .0001). RTIME was greater with the energy drink (p = .04), irrespective of time. A significant time X substance interaction (p = .036) for RTIPE indicated that RTIPE increased for both placebo and energy drink conditions pre ingestion to pre exercise, but the magnitude of increase was greater with the energy drink compared to placebo. This resulted in higher RTIPE post exercise for the energy drink condition. These results suggest that acute ingestion of a caffeine containing energy drink can enhance resistance exercise performance to failure and positively enhances psychophysiological factors related to exertion in trained males. Publisher statement: This is a non-final version of an article published in final form in Smith, M. , Cook, K. , James, R.S. and Duncan, M.J. (2012) The acute effect of a caffeine containing energy drink on mood state, readiness to invest effort and resistance exercise to failure. Journal of Strength & Conditioning Research, volume 26 (10): 2858–2865.
Bibliographical noteThis is a non-final version of an article published in final form in Smith, M. , Cook, K. , James, R.S. and Duncan, M.J. (2012) The acute effect of a caffeine containing energy drink on mood state, readiness to invest effort and resistance exercise to failure. Journal of Strength & Conditioning Research, volume 26 (10): 2858–2865.
- High-intensity exercise
- Resistance exercise
- Repetitions to failure