The Effects of Caffeine and Citrus Aurantium on Performance During Repeated Maximal Anaerobic Exercise Bouts in Habitual Caffeine Users.

ABSTRACT: McLester, CN, Bailey, P, Bechke, EE, Williamson, CM, McLester, JR, and Kliszczewicz, B. The effects of caffeine and Citrus aurantium on performance during repeated maximal anaerobic exercise bouts in habitual caffeine users. J Strength Cond Res 35(12): 3394-3399, 2021-The combination of caffeine (CAF) and Citrus aurantium (CA) have demonstrated the potential to improve various types of performance. To date, few studies have explored this relationship in purely anaerobic-based exercise. Therefore, the purpose of this study was to examine the influence of an acute dose of CAF + CA on peak anaerobic performance and the attenuation of power over multiple anaerobic bouts and to determine any differences in perceived effort or fatigue. Ten active men (25.1 ± 3.9 years) who habitually consumed caffeine volunteered to perform repeated anaerobic bouts on a cycle ergometer on 2 separate days, consuming either a placebo or 100 mg CAF + 100 mg CA. Significance was set at p ≤ 0.05 and repeated measures analysis of variance showed no main effects for peak power p = 0.520, mean power p = 0.926, minimum power p = 0.321, total work p = 0.924, time to peak power p = 0.536, or rate of fatigue p = 0.284. There was a time effect for all variables (p ≤ 0.05) with the exception of time to peak power (p = 0.181). There were no differences in any measures of perceived effort or fatigue between conditions (p ≥ 0.05), but there were time-dependent differences observed each day (p ≤ 0.05). Overall, an acute dosage of 100 mg CAF and 100 mg CA did not elicit any differences in anaerobic performance or in perceived measures of effort and fatigue in young males who habitually consume caffeine. Therefore, caution should be used when pairing CAF and CA for the goal of improving anaerobic performance, because no clear benefit was realized in this population at this dosage.

Influence of acute consumption of caffeine vs. placebo over Bia-derived measurements of body composition: a randomized, double-blind, crossover design.

BACKGROUND: Bioelectrical impedance analysis (BIA) is often used to estimate total body water (TBW), intracellular body water (ICW), extracellular body water (ECW), and body fat percentage (BF%). A common restriction for BIA analysis is abstinence from caffeine 12-h prior to testing. However, research has yet to determine whether the consumption of caffeine influences BIA testing results. The purpose of this study was to determine if the consumption of caffeine influences BIA-derived BF% and body water values in habitual caffeine users. METHODS: Twenty apparently healthy males (26.6 ± 4.1 years) identified as habitual caffeine consumers (≥ one 95 mg serving per day ≥ four days per week) participated in this study. Participants came to the lab on three occasions, the first visit serving as the control (CON) with no supplementation. The remaining two visits were performed in a randomized double-blind, cross-over fashion. Participants consumed 200 mg of dextrose (PLA) or caffeine (CAF) in capsule form. During each visit, seven multi-frequency BIA measurements were conducted before (PRE) and after (15-min, 30-min, 45-min, 60-min, 75-min, 90-min) consumption. RESULTS: Repeated measures ANOVA revealed BF% for CAF was lower than the CON and PLA conditions at PRE and 15-min (p < 0.001, p = 0.004), but not statistically significant for the remaining time points (i.e., 30-, 45-, 60-, 75-, and 90-min). However, the effect size (ES) of the BF% differences were trivial. The CON, PLA, and CAF conditions had higher PRE ICW values than their associated post time points (i.e., 15-, 30-, 45-, 60-, 75-, and 90-min). Similar to BF%, ES of the mean differences for ICW were trivial. No other differences were observed. CONCLUSION: Caffeine consumption in habitual users produced trivial changes in TBW, ECW, ICW, or BF%. Therefore, the pre-testing guidelines for caffeine consumption may not be necessary in habitual caffeine consumers.

Validity of DXA body volume equations in a four-compartment model for adults with varying body mass index and waist circumference classifications.

The purpose of this investigation was to determine the validity of 4-compartment (4C) model body fat percent (BF%) estimates when using dual energy x-ray absorptiometry (DXA) derived body volume (BV) equations (4C-DXA1 and 4C-DXA2) in adults with varying body mass index (BMI) and waist circumference (WC) classifications. Each model was compared to a criterion 4C model with air-displacement plethysmography (ADP) generated BV (4C-ADP). Participants were categorized as normal weight (n = 40; NW = BMI<25.0kg/m2); overweight (n = 40; OWBMI = BMI≥25.0 kg/m2); and overweight with at-risk WC (n = 35; OWBMI+WC = BMI≥25.0 kg/m2 and WC≥88.0cm for women and 102.0cm for men). 4C-DXA1 produced lower BF% than that derived using the 4C-ADP in NW (CE = -3.0%; p<0.001) while 4C-DXA2 was significantly higher (CE = 4.8%; p<0.001). The SEE and 95% limits of agreement (LOA) were lower for 4C-DXA2 (1.24% and ±2.5%, respectively) than 4C-DXA1 (2.59% and ±5.0%, respectively) and proportional bias was present for both (p<0.05). 4C-DXA1 BF% was not significant in OWBMI (CE = -0.5%; p = 0.112) whereas 4C-DXA2 was higher (CE = 4.5%; p<0.001). The SEE and 95% LOA were lower for 4C-DXA2 (1.20% and ±2.9%, respectively) than 4C-DXA1 (1.92% and ±3.9%, respectively) in OWBMI. Proportional bias was present for 4C-DXA1 (p = 0.007), but not 4C-DXA2 (p = 0.832). 4C-DXA1 and 4C-DXA2 produced significantly higher BF% in OWBMI+WC (CE = 2.2 and 2.3%, respectively; both p<0.001). The SEE and 95% LOA remained lower for 4C-DXA2 (1.15% and ±2.5%, respectively) than 4C-DXA1 (1.84% and ±3.8%, respectively). There was proportional bias for 4C-DXA2 (p = 0.020), but not 4C-DXA1 (p = 0.183) in OWBMI+WC. Only one prediction model (i.e., 4C-DXA1 in OWBMI+WC) revealed valid estimates of BF%. Practitioners are encouraged to use criteria for both BMI and WC when utilizing DXA-derived BV in 4C-models for normal and overweight populations.