Effects of 3 days of citrulline malate supplementation on short-duration repeated sprint running performance in male team sport athletes

Abstract

Citrulline malate (CM) is purported to be an ergogenic aid during various types of exercise performance. However, the effects of CM on repeated sprint performance (RSP) are under-explored. In a placebo-controlled, double-blind, counterbalanced cross-over design, male university-level team sport athletes (n = 13) performed two familiarization trials, after which CM or placebo (PLA) (8 × 1 g tablets each day) were taken on the 2 days prior to, and with breakfast on the morning of, each main experimental trial. The main experimental trials employed a RSP protocol consisting of 10 repetitions of 40 m maximal shuttle run test (MST) with a 30 s interval between the start of each sprint. Sprint times and heart rate were recorded throughout the MST, and blood lactate concentrations were measured before, immediately after, and 5 min after completing the MST. CM resulted in better RSP compared to PLA, as indicated by a lower sprint performance decrement (S_dec: CM, 4.68% ± 1.82% vs. PLA, 6.10% ± 1.83%; p = 0.03; ES = 0.77), which was possibly influenced by the fastest sprint time being faster in CM (CM, 8.16 ± 0.34 s vs. PLA, 8.29 ± 0.39 s; p = 0.011; ES = 0.34). There were no differences between CM and PLA in average sprint time (p = 0.54), slowest sprint time (p = 0.48), blood lactate concentrations (p = 0.73) or heart rate (p = 0.18), nor was there a condition × time interaction effect across the 10 sprints (p = 0.166). Three days of CM supplementation (8 g daily) attenuated the sprint performance decrement during short-duration high-intensity exercise in the form of running RSP in male university-level team sport athletes.

Keywords: ergogenic aid; lactate; maximal shuttle run test; performance decrement.

FIGURE 1

Timeline of events throughout the study. (A) Participants attended the laboratory for four visits. The first visit consisted of baseline assessments including age, height, body mass, and BMI, and familiarization with the RSP test; the second visit was a second familiarization with the RSP test; the third and fourth visits were the main experimental trials performed in a placebo‐controlled, double‐blind, cross‐over design of CM or PLA (8 g.day⁻¹) for 3 days (i.e., the 2 days prior to, and the day of each trial). (B) For each experimental trial, 3 h after the last administration of either supplement with breakfast, and after a brief warm‐up, the participants undertook the RSP test. (C) The RSP test required participants to complete ten repetitions of 40 m maximal shuttle run test with a 30 s interval between the start of each sprint (*, recovery time between sprints was equivalent to 30 s minus the time taken to complete the previous sprint). Sprint times (↓) and heart rate (♥) were recorded throughout the RSP protocol, and blood lactate concentrations (●) were measured before, immediately after and 5 min after completing the RSP. BMI, body mass index; CM, citrulline malate; g, grams; h, hours; m, meters; min, minutes; PLA, placebo; RSP, repeated sprint performance; s, seconds.

FIGURE 2

Sprint times over the individual sprints across the MST (A), heart rate during the MST (B), and blood lactate concentration, assessed before (PRE), immediately after (POST) and 5 min after (+5 min POST) completing the MST (C). Data are presented as mean values, with error bars representing standard deviation (n = 13). CM, citrulline malate; MST, 40 m maximal shuttle run test; PLA, placebo.

FIGURE 3

FT (A), average sprint time (B), and ST (C) during the MST. Data are presented as mean values, with error bars representing standard deviation (n = 13). *p = 0.011 and ES = 0.34 for FT between PLA and CM. CM, citrulline malate; FT, fastest sprint time; PLA, placebo; ST, slowest sprint time.

FIGURE 4

Performance decrement (A), and mean difference in % S_dec (B) during each trial. Data are presented as mean values, with error bars representing standard deviation (n = 13). *p = 0.034 and ES = 0.77 for performance decrement between PLA and CM. The shaded area in (B) represents the range for the smallest worthwhile difference in S_dec in this cohort, and the short horizontal line and error bars represent mean difference and 95% CI, respectively, comparing CM to PLA. S_dec: sprint performance decrement; CM, citrulline malate; PLA, placebo.