The Effect Of Acute Citrulline Malate Supplementation On Oxygen Saturation And Handgrip Critical Force

Citrulline malate (CM) has possible exercise performance enhancement abilities due to the vasodilatory effect of nitric oxide via citrulline combined with possible increases in mitochondrial efficiency from malate. Critical force, an analog to critical power, is highly dependent on oxygen delivery and aerobic metabolism and has been validated in the forearm flexor muscles. Acute CM supplementation influences on an aerobic function test like a handgrip critical force test (HGCF) are not well understood. PURPOSE: The purpose of this study was to investigate how 12 g of CM affects oxygen saturation/desaturation and in the forearm flexor muscles during a HGCF test in women aged 18-35 years. METHODS: Seventeen female participants completed three visits consisting of one familiarization and two experimental. This study utilized a randomized, double-blind, crossover design where participants drank either a CM or placebo solution, underwent a 1-Hr rest period, and then performed the HGCF test which consisted of 60 maximal contractions utilizing a 3-sec:2-sec on/off duty cycle. Oxygenated hemoglobin (OxHb) and deoxygenated hemoglobin (HHb) values were recorded on the superficial flexor muscles via Near-Infrared Spectroscopy which were then normalized to each participant’s 0% oxygenation and 100% oxygenation values during a 5-min occlusion period. Area under/over the curve (AUC/AOC), 20-second averages during the test, and the mean critical force-time integral (FTI) of the last 6 contractions were measured for each of these variables. RESULTS: No statistical differences for AUC of OxHb (p = 0.88, CM: 3963.5 ± 2522.5, PL: 3860.5 ± 3789.8) and AOC of HHb (p = 0.72, CM: 14232 ± 5987.9, PL: 15535.8 ± 6878.0) were found. There was no main effect for condition for OxHb (p = 0.283) or HHB (p = 0.738), but there was a significant main effect for time for both (p < 0.001). There were no significant differences for the mean critical FTI of the last 6 contractions (p = 0.093, CM: 209.08 ± 65.4 N·s2, PL: 194.22 ± 79.3 N·s2). CONCLUSION: In conclusion, an acute, 12 g dose of CM had no influence on oxygen saturation/desaturation or the total amount of work done during the final 6 contractions during a HGCF test. However, the oxygen consumption patterns seen in this study during the handgrip test were similar to other critical force tests. Grant from University of Oklahoma, Robberson Scholarship