Practical Issues in Evidence-Based Use of Performance Supplements: Supplement Interactions, Repeated Use and Individual Responses

Abstract

Current sports nutrition guidelines recommend that athletes only take supplements following an evidence-based analysis of their value in supporting training outcomes or competition performance in their specific event. While there is sound evidence to support the use of a few performance supplements under specific scenarios (creatine, beta-alanine, bicarbonate, caffeine, nitrate/beetroot juice and, perhaps, phosphate), there is a lack of information around several issues needed to guide the practical use of these products in competitive sport. First, there is limited knowledge around the strategy of combining the intake of several products in events in which performance benefits are seen with each product in isolation. The range in findings from studies involving combined use of different combinations of two supplements makes it difficult to derive a general conclusion, with both the limitations of individual studies and the type of sporting event to which the supplements are applied influencing the potential for additive, neutral or counteractive outcomes. The repeated use of the same supplement in sports involving two or more events within a 24-h period is of additional interest, but has received even less attention. Finally, the potential for individual athletes to respond differently, in direction and magnitude, to the use of a supplement seems real, but is hard to distinguish from normal day to day variability in performance. Strategies that can be used in research or practice to identify whether individual differences are robust include repeat trials, and the collection of data on physiological or genetic mechanisms underpinning outcomes.

The acute effects of caffeine intake on time under tension and power generated during the bench press movement

“…Optimization of resistance training and the pattern of adaptive changes related to the development of muscular strength and power have been the focus of interest of scientists from different fields of studies [3][4][5][6]. In addition to training, diet and supplementation also have a significant effect on adaptation and post-exercise responses [7][8][9][10][11][12]. To date, few supplements have been shown to have a direct ergogenic effect on physical capacity.…”

Methodologies for Investigating Performance Changes With Supplement Use

“…Scenarios in which this might occur include the simultaneous use of several products with individual benefits in the acute scenario of competition, or the acute use of supplements in conjunction with a chronically applied supplement used to support training outcomes. A recent review of the available literature on such supplement combinations noted that even when the focus is restricted to a few performance supplements (e.g., caffeine, creatine, beta-alanine, bicarbonate, nitrate/beetroot juice, and phosphate), and the specific scenarios in which there is evidence-based justification of their use, a large number of permutations of supplement use combinations can be identified (Burke, 2017). For example, each of these six performance supplements, when used in isolation, could theoretically provide a benefit to the preparation (beta-alanine, creatine) or performance (caffeine, beta-alanine bicarbonate, nitrate, phosphate) of a 4,000-m track cycling pursuit, 400-m swim, or 2,000-m rowing race (Burke, 2017).…”

“…Yet, such research is important, in light of the potential for a number of different types of interactions to occur. For performance supplements with related mechanisms, such as bicarbonate and beta-alanine supplementation, which target the fatigue associated with excessive muscle acidosis, combined use might be additive or neutral (Burke, 2017). Meanwhile, for those with independent mechanisms, combined use could be additive, neutral, or counterproductive.…”

“…Be prepared to use a more sophisticated statistical analysis to account for differences in conditions. advantage or to meet the logistical requirements of competition spacing; (2) desensitization of physiological systems may render the subsequent use of a supplement less effective; (3) residual fatigue left from enhanced performance in the first event may carry over to the subsequent event (Burke, 2017). The corollary to these possibilities include an altered protocol (timing and dose), the decision not to use the supplement on all occasions, or the need to modify pacing strategies for earlier events.…”

The Use of Sports Nutrition by Students in Chelyabinsk: A Case Study

“…At the same time, many athletes use sports nutrition at their peril and risk, without using the advice of specialists. However, if athletes do not have a deficiency of macro and micronutrients, then the use of nutritional supplements may not only not improve the effectiveness of training but may have a negative impact on their physical performance and health [8].…”