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Neil D. Clarke, Darren L. Richardson, James Thie and Richard Taylor

Context : Caffeine, often in the form of coffee, is frequently used as a supplement by athletes in an attempt to facilitate improved performance during exercise. Purpose: To investigate the effectiveness of coffee ingestion as an ergogenic aid prior to a 1-mile (1609 m) race. Methods: In a double-blind, randomized, cross-over, and placebo-controlled design, 13 trained male runners completed a 1-mile race 60 minutes following the ingestion of 0.09 g·kg−1 coffee (COF), 0.09 g·kg−1 decaffeinated coffee (DEC), or a placebo (PLA). All trials were dissolved in 300 mL of hot water. Results: The race completion time was 1.3% faster following the ingestion of COF (04:35.37 [00:10.51] compared with DEC (04:39.14 [00:11.21]; P = .018; 95% confidence interval [CI], −0.11 to −0.01; d = 0.32) and 1.9% faster compared with PLA (04:41.00 [00:09.57]; P = .006; 95% CI, −0.15 to −0.03; d = 0.51). A large trial and time interaction for salivary caffeine concentration was observed (P < .001; ηp2=.69), with a very large increase (6.40 [1.57] μg·mL−1; 95% CI, 5.5–7.3; d = 3.86) following the ingestion of COF. However, only a trivial difference between DEC and PLA was observed (P = .602; 95% CI, −0.09 to 0.03; d = 0.17). Furthermore, only trivial differences were observed for blood glucose (P = .839; ηp2=.02) and lactate (P = .096; ηp2=.18) and maximal heart rate (P = .286; ηp2=.13) between trials. Conclusions: The results of this study show that 60 minutes after ingesting 0.09 g·kg−1 of caffeinated coffee, 1-mile race performance was enhanced by 1.9% and 1.3% compared with placebo and decaffeinated coffee, respectively, in trained male runners.

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Alasdair Strokosch, Loic Louit, Laurent Seitz, Richard Clarke and Jonathan D. Hughes

This study investigated the efficacy of deadlifts and box squats, with a combination of traditional and accommodating resistance, as a postactivation potentiating stimulus of standing broad jumps (SBJ) in a multiple-set contrast protocol. Twelve professional rugby league players (21.4 [2.5] y; 181.3 [8.3] cm, 91.9 [8.8] kg; 1-repetition-maximum [1RM] back squat/body mass 1.59 [0.21]; 1RM deadlift/body mass 2.11 [0.25]; ≥3-y resistance-training experience) performed baseline SBJ before a contrast postactivation potentiating protocol involving 2 repetitions of 85% 1RM box squat or deadlifts, loaded with a combination of traditional barbell weight (70% 1RM) and elastic-band resistance (∼15% 1RM), followed by 2 SBJs. Exercises were separated by 90 s, and 4 contrast pairs were performed in total. Using a repeated-measures design, all subjects performed the squat followed by the deadlift and finally the control (SBJ only) condition in the same order across consecutive weeks. Changes from baseline in SBJ distance were moderate for the box squat (effect size [ES] = 0.64–1.03) and deadlift (ES = 0.80–0.96) and trivial in the control condition (ES = 0.02–0.11). The magnitude of differences in postactivation potentiating effect were considered moderate (d = 0.61) for set 1, trivial for set 2 (d = 0.10) and set 3 (d = 0.05) in favor of box squats, and moderate for set 4 (d = 0.58) in favor of deadlifts. Accommodating resistance in either box squats or deadlifts is an effective means of potentiating SBJ performance across multiple sets of a contrast protocol with only 90-s rest.