Oral and topical sodium bicarbonate supplementation as ergogenic strategies in team sports

Sodium bicarbonate (SB) is an extracellular buffering aid that improves high-intensity intermittent exercise performance by protecting against biochemical disturbances that contribute to skeletal muscle fatigue. Ergogenic effects of SB have been widely studied, but research investigating its efficacy in team sport contexts was lacking. Practical application of SB is thought to be limited by the occurrence of gastrointestinal (GI) side-effects. A novel topical muscle cream, PR Lotion, was first launched in 2018, and is purported to deliver SB into systemic circulation via the transdermal route and eliminate the risk of GI discomfort. Research examining the efficacy of topical SB as an ergogenic strategy was needed to determine whether it could be a suitable alternative to traditional approaches. This PhD, therefore, adopted a pragmatic, real-world approach, and followed an applied research model to establish the optimum SB supplementation strategy for improving exercise performance and recovery in team sports. Study one explored the prevalence, implementation and barriers of SB supplementation by practitioners. Poor prevalence rates were mostly attributed to concerns about GI side-effects after SB ingestion. Study two compared the effect of oral and topical SB during a battery of team sport-specific exercise tests: countermovement jumps (CMJ), 8 x 25 m repeated sprints, and Yo-Yo Intermittent Recovery Test Level 2 (Yo-Yo IR2). Faster repeated sprint times suggested oral and topical SB might be ergogenic strategies for team sport athletes. Study three assessed the efficacy of oral and topical SB for offsetting the decline in repeated sprint ability (RSA) throughout simulated soccer match play exercise. Sprint times (8 x 25 m) were maintained at half-time (HT) and post-exercise for oral but not topical SB. More pronounced changes in extracellular buffering capacity and strong ions were shown for oral SB. Study four investigated the influence of oral and topical SB on functional recovery and soccer-specific performance following exercise-induced muscle damage (EIMD). Neither strategy accelerated recovery up to 3-d post EIMD, but oral SB rescued Illinois agility test (IAT) and Yo-Yo IR2 performance. Results from this PhD offer empirical evidence confirming oral SB as the optimum strategy for improving performance, or counteracting fatigue-related impairments in recreational team sport athletes. These benefits are likely underpinned by elevated extracellular buffering capacity and greater regulation of strong ion balance. Insufficient evidence currently exists to recommend PR Lotion as an ergogenic strategy. Practitioners should adopt evidence-based practices when prescribing oral SB to ensure laboratory findings are effectively translated into applied nutritional regimes in team sports.