ECSS Paris 2023: CP-PN04
INTRODUCTION: This study investigated the effect of pre-match caffeine supplementation on the performance in rugby seven matches in collegiate male players. METHODS: This study adopted a placebo-controlled crossover design. Seven participant engaged in two rugby sevens friendly matches each day on two consecutive days, separated by a 13-day washout period. The participants in the caffeine trial (CA) consumed 3 mg/kg body weight caffeine in a capsule 1 h before each match, while those in the placebo trial (PL) consumed a capsule containing starch. Movement patterns during the matches, including total distance, distance in several speed zones, distances and frequency of acceleration and deceleration, and frequency of collisions and repeated high-intensity effort (RHIE), were recorded using wearable GPS devices. The differences between the two trials in movement patterns in the entire match and first and second halves were analyzed with paired t-test and effect size was calculated using Cohen’s d. RESULTS: The participants in CA exhibited longer total distance in the match 1 (CA: 1485.8 ± 67.9 ; PL: 1346.9 ± 83.8 m, d=0.743), 3 (CA: 1394.7 ± 50.3; PL: 1312.9 ± 46.6 m, d=0.690), and 4 (CA: 1502.5 ± 89.9; PL: 1359.2 ± 67.5 m, d=0.736) with moderate effect sizes. The increased distance came mostly from faster speed zones. The participants in CA had longer distance in high intensity running (18-20 km/h) in match 1 (CA: 90.6 ± 25.1; PL: 54.1 ± 10.6 m, d=0.773) and 4 (CA: 76.5 ± 18.1; PL: 58.7 ± 11.6 m, d=0.479). The participants in CA had longer distance in acceleration in match 1 (CA: 58.03 ± 3.76; PL: 49.89 ± 5.45 m, d=0.710) and 3 (CA: 64.51 ± 5.59; PL: 51.85 ± 9.54 m, d=0.661). Conversely, the participants in PL walked (0-6 km/h) longer distance in match 4 (CA: 585.9 ± 21.8; PL: 629.4 ± 21.3 m, d=0.824) with large effect size. The participants in CA had higher frequency of RHIE in the first half in match 1 (CA: 4.83 ± 0.75; PL: 3.50 ± 0.56, d=0.822) and 3 (CA: 4.67 ± 0.42; PL: 3.33 ± 0.49, d=1.185) and the second half in match 4 (CA: 5.00 ± 0.45; PL: 4.17 ± 0.70, d=0.577). The participants in CA also had higher frequency of collision in the first half in match 1 (CA: 2.50 ± 0.89; PL: 1.00 ± 0.52, d=0.845) and 4 (CA: 2.17 ± 0.48; PL: 1.33 ± 0.62, d=0.618) and the second half in match 4 (CA: 2.67 ± 0.80; PL: 1.17 ± 0.40, d=0.965). Moreover, the participants in CA exhibited higher frequency of deceleration in the first half in match 1 (CA: 9.50 ± 1.20; PL: 7.00 ± 0.73, d=1.025), 2 (CA: 9.00 ± 1.21; PL: 7.33 ± 1.17,d=0.571), 3 (CA: 10.50 ± 1.71; PL: 6.17 ± 1.01, d=1.260), and 4 (CA: 9.67 ± 1.17; PL: 8.17 ± 1.14, d=0.530). CONCLUSION: The results of this study suggested that caffeine supplementation before rugby sevens matches may improve overall and high intensity running distance and increase the frequency RHIE, collision, and deceleration in male collegiate players.
Read CV CHANG-LI HSUEHECSS Paris 2023: CP-PN04
INTRODUCTION: The ergogenic effect of caffeine on sports performance has been analyzed in numerous studies, becoming one of the sports supplements with the greatest proven benefits. Scientific evidence shows that acute caffeine intake improves muscle strength, power and endurance in upper and lower body exercises. However, in these studies, female participants are underrepresented, and consequently, we have limited evidence about the effect of caffeine on women. Moreover, the sex differences in the ergogenic effect of caffeine on muscular strength, power, and endurance performance have been scarcely explored. METHODS: Seventy-six resistance-trained participants (male/female: 38/38; age: 23±3 years; resistance training experience: 2.7±2.0 years; 1RM/kg bench press: >1.0; 1RM/kg back squat: <1.2) participated in a double-blind, placebo-controlled, cross-over and randomized study. Participants were provided with either 3 mg/kg of body mass of caffeine or a placebo, and sixty minutes after the ingestion, they performed muscular strength and power assessment for the bench press and back squat exercises at 25%, 50%, 75%, and 90% 1-repetition-maximum (1RM), performing 3, 2, 1 and 1 repetitions, respectively. Muscular endurance was then assessed for both exercises at 65% 1RM, performing one set until task failure for each exercise. RESULTS: Compared to placebo, caffeine improved mean and peak velocity and power output (ANOVA effect, P<0.001), but no supplement by sex effect was found for any of these variables. Nonetheless, supplement by exercise type effect in Vmean (P=0.049). Caffeine increased Vmean in the back squat exercise in males and females at 50%1RM (males and females, 4.5% and 4.6%, P=0.001), 75%1RM (5.2% and 5.7%, P=0.001) and 90%1RM (7.9% and 7.8%, P< 0.030). Similarly, in Wmean, supplement by exercise type by load was found (P = 0.045), caffeine increased in the back squat exercise in males and females at 50%1RM (5.3% and 4.6%, P < 0.040), 75%1RM (5.7% and 5.5%, P<0.001) and 90%1RM (8.5% and 6.5%, P<0.028) compared to placebo. In muscular endurance, a supplement effect was detected in the number of repetitions (reps), Vmean, Wmean and Wpeak (ANOVA, P < 0.001). However, no supplement by sex effect was found for any of these variables. CONCLUSION: Low doses of caffeine (3 mg/kg) cause a similar ergogenic effect on muscular strength, power and endurance performance in upper- and lower-body exercises between male and female resistance-trained participants. Moreover, caffeines effect was more pronounced at moderate- high loads (>50%1RM) and according to muscle size groups (back squat vs. bench press) but irrespective to sex, which indirectly reinforced the idea of the central mechanism of action of caffeine.
Read CV Juan Jesús Montalvo AlonsoECSS Paris 2023: CP-PN04
INTRODUCTION: There is a strong evidence base for the effectiveness of caffeine and nitrate supplementation on sports performance. Although performance-enhancing benefits have been observed with both caffeine and nitrates used separately, it is unclear whether their combined use has an additive effect. Therefore, the aim of this study was to investigate the effect of individual and combined caffeine and nitrate intake on the anaerobic performance of highly trained judo athletes in both upper and lower body, replicating the combat conditions of the athletes. METHODS: Twenty-five highly trained judo athletes (age: 20 ± 2 years, body mass: 75.9 ± 8.9 kg) habituated to caffeine (2.2 mg/kg/day) participated in a randomized, double-blind, placebo-controlled, parallel-group experiment. Each participant was randomly assigned to one of the following groups: (a) a caffeine placebo (PLAC-CAF) + a beetroot juice placebo (PLAC-BJ) [n=6]; or (b) 6 mg/kg body mass (BM) of caffeine (CAF) + PLAC-BJ [n=4]; or (c) beetroot juice (BJ) + PLAC-CAF [n=7]; or (d) CAF + BJ [n=8]. In each condition athletes ingested 2 x 70 ml of concentrated beetroot juice containing either 400 mg of nitrate or no nitrate for 2 days and 2 × 70 ml 2.5 h prior to each test session. Caffeine or placebo tablets were administered 45 min before the test session. Each session consisted of four 30-s Wingate tests performed with a constant load equivalent to 4.5% and 7.5% of BM for the upper and lower body, respectively. The subjects first performed the upper body test and then, after 1 minute of passive rest, started the lower body test. This protocol was repeated after 3 minutes of passive rest. RESULTS: The two-way repeated measures ANOVA (4 substance 2 Wingate tests) did not show any significant interactions for Relative Peak Power Output (for upper body Wingate test (UBW): p=0.342 and lower body Wingate test (LBW): p=0.143), Fatigue Slope (for UBW: p=0.723 and LBW: p=0.188), Total Work (for UBW: p=0.131 and LBW: p=0.131), nor main effects of group on Relative Peak Power Output (for UBW: p=0.445 and LBW: p=0.532), Fatigue Slope (for UBW: p=0.366 and LBW: p=0.604) and Total Work (for UBW: p=0.131 and LBW: p=0.69). However, it showed significant main effects of the time on Relative Peak Power Output (for UBW: p<0.001 and LBW: p<0.001), Fatigue Slope (for UBW: p<0.001 and LBW: p<0.001) and Total Work (for UBW: p=0.022 and LBW: p<0.001). CONCLUSION: The present study suggests that neither single nor combined dose of 6 mg/kg BM of caffeine, along with chronic nitrate supplementation, is effective in improving anaerobic performance, as assessed by a repeated 30-s Wingate test for both the upper and lower body in highly trained judo athletes habituated to caffeine.
Read CV Magdalena KaszubaECSS Paris 2023: CP-PN04