Background Interest into the health, disease, and performance impact of exogenous ketone bodies has rapidly expanded due to their multifaceted physiological and signaling properties but limiting our understanding is the isolated analyses of individual types and dose/dosing protocols. Methods Thirteen recreational male distance runners (24.8 ± 9.6 years, 72.5 ± 8.3 kg, VO2max 60.1 ± 5.4 ml/kg/min) participated in this randomized, double-blind, crossover design study. The first two sessions consisted of a 5-km running time trial familiarization and a VO2max test. During subsequent trials, subjects were randomly assigned to one (KS1: 22.1 g) or two (KS2: 44.2 g) doses of beta-hydroxybutyrate (βHB) and medium chain triglycerides (MCTs) or flavor matched placebo (PLA). Blood R-βHB, glucose, and lactate concentrations were measured at baseline (0-min), post-supplement (30 and 60 min), post-exercise (+ 0 min, + 15 min). Time, heart rate (HR), rating of perceived exertion (RPE), affect, respiratory exchange ratio, oxygen consumption (VO2), carbon dioxide production, and ventilation were measured during exercise. Cognitive performance was evaluated prior to and post-exercise. Results KS significantly increased R-βHB, with more potent and prolonged elevations in KS2, illustrating an administrative and dosing effect. R-βHB was significantly decreased in KS1 compared to KS2 illustrating a dosing and exercise interaction effect. Blood glucose elevated post-exercise but was unchanged across groups. Blood lactate significantly increased post-exercise but was augmented by KS administration. Gaseous exchange, respiration, HR, affect, RPE, and exercise performance was unaltered with KS administration. However, clear responders and none-responders were indicated. KS2 significantly augmented cognitive function in pre-exercise conditions, while exercise increased cognitive performance for KS1 and PLA to pre-exercise KS2 levels. Conclusion Novel βHB + MCT formulation had a dosing effect on R-βHB and cognitive performance, an administrative response on blood lactate, while not influencing gaseous exchange, respiration, HR, affect, RPE, and exercise performance.

Numerous oral ketone supplements are marketed with the claim that they will rapidly induce ketosis and improve exercise performance. The purpose of this study was to assess exercise performance time and related physiological, metabolic and perceptual responses of recreational endurance runners after ingestion of a commercially available oral ketone supplement. Recreational endurance runners (n = 10; age: 20.8 ± 1.0 years; body mass: 68.9 ± 5.6 kg; height: 175.6 ± 4.9 cm) participated in a double-blind, crossover, repeated-measures study where they were randomized to 300 mg.kg-1 body weight of an oral β-hydroxybutyrate-salt + Medium Chain Triglyceride (βHB-salt+MCT) ketone supplement or a flavor matched placebo (PLA) 60 min prior to performing a 5-km running time trial (5KTT) on a treadmill. Time, HR, RPE, affect, RER, VO2, VCO2, and VE were measured during the 5-km run. The Session RPE and affect (Feeling Scale) were obtained post-5KTT. Plasma glucose, lactate and ketones were measured at baseline, 60-min post-supplement, and immediately post-5KTT. Plasma R-βHB (endogenous isomer) was elevated from baseline and throughout the entire protocol under the βHB-salt+MCT condition (p < 0.05). No significant difference (58.3 ± 100.40 s; 95% CI: -130.12 – 13.52; p = 0.100) was observed between the βHB-salt+MCT supplement (1430.0 ± 187.7 s) and the PLA (1488.3 ± 243.8 s) in time to complete the 5KTT. No other differences (p > 0.05) were noted in any of the other physiological, metabolic or perceptual measures.

High carbohydrate, low fat (HCLF) diets have been the predominant nutrition strategy for athletic performance, but recent evidence following multi-week habituation has challenged the superiority of HCLF over low carbohydrate, high fat (LCHF) diets, along with growing interest in the potential health and disease implications of dietary choice. Highly trained competitive middle-aged athletes underwent two 31-day isocaloric diets (HCLF or LCHF) in a randomized, counterbalanced, and crossover design while controlling calories and training load. Performance, body composition, substrate oxidation, cardiometabolic, and 31-day minute-by-minute glucose (CGM) biomarkers were assessed. We demonstrated: (i) equivalent high-intensity performance (@∼85%VO2max), fasting insulin, hsCRP, and HbA1c without significant body composition changes across groups; (ii) record high peak fat oxidation rates (LCHF:1.58 ± 0.33g/min @ 86.40 ± 6.24%VO2max; 30% subjects &gt; 1.85 g/min); (iii) higher total, LDL, and HDL cholesterol on LCHF; (iv) reduced glucose mean/median and variability on LCHF. We also found that the 31-day mean glucose on HCLF predicted 31-day glucose reductions on LCHF, and the 31-day glucose reduction on LCHF predicted LCHF peak fat oxidation rates. Interestingly, 30% of athletes had 31-day mean, median and fasting glucose &gt; 100 mg/dL on HCLF (range: 111.68-115.19 mg/dL; consistent with pre-diabetes), also had the largest glycemic and fat oxidation response to carbohydrate restriction. These results: (i) challenge whether higher carbohydrate intake is superior for athletic performance, even during shorter-duration, higher-intensity exercise; (ii) demonstrate that lower carbohydrate intake may be a therapeutic strategy to independently improve glycemic control, particularly in those at risk for diabetes; (iii) demonstrate a unique relationship between continuous glycemic parameters and systemic metabolism.

Recently we reported similar performances in both progressive tests to exhaustion (VO 2 max) and 5km running time trials (5KTT) after consuming low-carbohydrate, high-fat (LCHF) or high-carbohydrate, low-fat (HCLF) diets. Accordingly, we tested the null hypothesis that the metabolic responses during both tests would be similar across diets. In a randomized, counterbalanced, cross-over design, seven male athletes (VO 2 max: 61.9 ± 6.1 mL/kg/min; age: 35.6 ± 8.4 years; height: 178.7 ± 4.1 cm; mass: 68.6 ± 1.6 kg; body fat: 5.0 ± 1.3%) completed six weeks of LCHF (6/69/25% energy carbohydrate/fat/protein) and HCLF (57/28/15% energy carbohydrate/fat/protein) diets, separated by a two-week washout. Substrate utilization and energy expenditure were measured during VO 2 max tests and 5KTTs. The LCHF diet markedly increased fat oxidation and reduced carbohydrate oxidation, with no associated impairment in either the VO 2 max tests or the 5KTTs. Following the LCHF diet, athletes generated 50% or more of their energy requirements from fat at exercise intensities up to 90% VO 2 max and reached the crossover point for substrate utilization at ~85% VO 2 max. In contrast, following the HCLF diet, carbohydrate provided more than 50% of the total energy consumption at all exercise intensities. During the 5KTT, ~56% of energy was derived from fat following the LCHF diet whereas more than 93% of the energy came from carbohydrate following the HCLF diet. This study provides evidence of greater metabolic flexibility following LCHF eating and challenges the popular doctrines of “carbohydrate dependence” for high intensity exercise and the role dietary macronutrients play in human performance.

Buxton, JD, Prins, PJ, Miller, MG, Moreno, A, Welton, GL, Atwell, AD, Talampas, TR, and Elsey, GE. The effects of a novel quadrupedal movement training program on functional movement, range of motion, muscular strength, and endurance. J Strength Cond Res 36(8): 2186–2193, 2022—Quadrupedal movement training (QMT) is a form of bodyweight training incorporating animal poses, transitions, and crawling patterns to reportedly improve fitness. This type of training may improve multiple facets of fitness, unfortunately, little evidence exists to support commercial claims and guide practitioners in the best use of QMT. Therefore, the purpose of this study was to assess the impact of a commercially available QMT program on functional movement, dynamic balance, range of motion, and upper body strength and endurance. Forty-two active college-age (19.76 ± 2.10 years) subjects (males = 19, females = 23) were randomly assigned to a QMT (n = 21) or control (CON) (n = 21) group for 8 weeks. Quadrupedal movement training consisted of 60-minute classes performed 2×·wk−1 in addition to regular physical activity. Active range of motion, Functional Movement Screen (FMS), Y-Balance Test (YBT), handgrip strength, and push-up endurance were assessed before and after the intervention. The QMT group showed significantly greater improvements than the CON group in FMS composite score (1.62 ± 1.53 vs. 0.33 ± 1.15, p = 0.004) and FMS advanced movements (0.81 ± 0.87 vs. 0.01 ± 0.71, p = 0.002) and fundamental stability (0.57 ± 0.75 vs. 0.05 ± 0.50, p = 0.011), along with hip flexion, hip lateral rotation, and shoulder extension (p < 0.05). No significant differences between groups were observed for dynamic balance or upper body strength and endurance. Our results indicate that QMT can improve FMS scores and various active joint ranges of motion. Quadrupedal movement training is a viable alternative form of training to improve whole-body stabilization and flexibility.