Browsing by Author "Currier, Brad S."
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Item Caffeine Timing Improves Lower-Body Muscular Performance: A Randomized Trial(2020) Harty, Patrick S. (TTU); Zabriskie, Hannah A.; Stecker, Richard A.; Currier, Brad S.; Tinsley, Grant M. (TTU); Surowiec, Kazimierz (TTU); Jagim, Andrew R.; Richmond, Scott R.; Kerksick, Chad M.Little is known about the optimal time to consume caffeine prior to exercise to maximize the ergogenic benefits of the substance. Purpose: To determine the optimal pre-exercise time interval to consume caffeine to improve lower-body muscular performance. A secondary aim was to identify the presence of any sex differences in responses to timed caffeine administration. Methods: Healthy, resistance-trained males (n = 18; Mean±SD; Age: 25.1 ± 5.7 years; Height: 178.4 ± 7.1 cm; Body mass: 91.3 ± 13.5 kg; Percent body fat: 20.7 ± 5.2; Average caffeine consumption: 146.6 ± 100.3 mg/day) and females (n = 11; Mean ± SD; Age: 20.1 ± 1.6 years; Height: 165.0 ± 8.8 cm; Body mass: 65.8 ± 10.0 kg; Percent bodyfat: 25.8 ± 4.2; Average caffeine consumption: 111.8 ± 91.7 mg/day) participated in this investigation. In a randomized, double-blind, placebo-controlled, crossover fashion, participants consumed 6 mg·kg−1 caffeine or placebo solution at three time points: 2 h prior (2H), 1 h prior (1H), or 30 min prior (30M) to exercise testing. During three visits, caffeine was randomly administered at one time point, and placebo was administered at the other two time points. During one visit, placebo was administered at all three time points. Next, participants performed isometric mid-thigh pulls (IMTP), countermovement vertical jumps (CMVJ), and isometric/isokinetic knee extensor testing (ISO/ISOK). Results: Caffeine administered at 1H significantly improved absolute CMVJ and ISO performance relative to placebo. Mean CMVJ jump height was significantly higher during 1H compared to 30M. However, only caffeine administered at 30M significantly improved absolute measures of isokinetic performance. Analysis of the pooled caffeine conditions revealed that muscular performance was more consistently augmented by caffeine in males compared to females. Conclusions: Pre-exercise caffeine timing significantly modulated participant responses to the substance, with 1H exerting the most consistent ergogenic benefits relative to other time points, particularly compared to 2H. Male participants were found to respond more consistently to caffeine compared to female participants. These results suggest that active individuals can maximize the ergogenic effects of caffeine by consuming the substance ~1 h prior to the point when peak muscular performance is desired.Item Effects of daily 24-gram doses of rice or whey protein on resistance training adaptations in trained males(2020) Moon, Jessica M.; Ratliff, Kayla M.; Blumkaitis, Julia C.; Harty, Patrick S. (TTU); Zabriskie, Hannah A.; Stecker, Richard A.; Currier, Brad S.; Jagim, Andrew R.; Jäger, Ralf; Purpura, Martin; Kerksick, Chad M.Background: Large (48-g), isonitrogenous doses of rice and whey protein have previously been shown to stimulate similar adaptations to resistance training, but the impact of consuming smaller doses has yet to be compared. We evaluated the ability of 24-g doses of rice or whey protein concentrate to augment adaptations following 8 weeks of resistance training. Methods: Healthy resistance-trained males (n = 24, 32.8 ± 6.7 years, 179.3 ± 8.5 cm, 87.4 ± 8.5 kg, 27.2 ± 1.9 kg/m2, 27.8 ± 6.0% fat) were randomly assigned and matched according to fat-free mass to consume 24-g doses of rice (n = 12, Growing Naturals, LLC) or whey (n = 12, NutraBio Labs, Inc.) protein concentrate for 8 weeks while completing a standardized resistance training program. Body composition (DXA), muscular strength (one-repetition maximum [1RM]) and endurance (repetitions to fatigue [RTF] at 80% 1RM) using bench press (BP) and leg press (LP) exercises along with anaerobic capacity (Wingate) were assessed before and after the intervention. Subjects were asked to maintain regular dietary habits and record dietary intake every 2 weeks. Outcomes were assessed using 2 × 2 mixed (group x time) factorial ANOVA with repeated measures on time and independent samples t-tests using the change scores from baseline. A p-value of 0.05 and 95% confidence intervals on the changes between groups were used to determine outcomes. Results: No baseline differences (p > 0.05) were found for key body composition and performance outcomes. No changes (p > 0.05) in dietary status occurred within or between groups (34 ± 4 kcal/kg/day, 3.7 ± 0.77 g/kg/day, 1.31 ± 0.28 g/kg/day, 1.87 ± 0.23 g/kg/day) throughout the study for daily relative energy (34 ± 4 kcals/kg/day), carbohydrate (3.7 ± 0.77 g/kg/day), fat (1.31 ± 0.28 g/kg/day), and protein (1.87 ± 0.23 g/kg/day) intake. Significant main effects for time were revealed for body mass (p = 0.02), total body water (p = 0.01), lean mass (p = 0.008), fat-free mass (p = 0.007), BP 1RM (p = 0.02), BP volume (p = 0.04), and LP 1RM (p = 0.01). Changes between groups were similar for body mass (− 0.88, 2.03 kg, p = 0.42), fat-free mass (− 0.68, 1.99 kg, p = 0.32), lean mass (− 0.73, 1.91 kg, p = 0.37), fat mass (− 0.48, 1.02 kg, p = 0.46), and % fat (− 0.63, 0.71%, p = 0.90). No significant between group differences were seen for BP 1RM (− 13.8, 7.1 kg, p = 0.51), LP 1RM (− 38.8, 49.6 kg, p = 0.80), BP RTF (− 2.02, 0.35 reps, p = 0.16), LP RTF (− 1.7, 3.3 reps, p = 0.50), and Wingate peak power (− 72.5, 53.4 watts, p = 0.76) following the eight-week supplementation period. Conclusions: Eight weeks of daily isonitrogenous 24-g doses of rice or whey protein in combination with an eight-week resistance training program led to similar changes in body composition and performance outcomes. Retroactively registered on as NCT04411173.