The Effects of Citrulline Malate Supplementation on Muscle Soreness and Contractile Function

Abstract

The consumption of citrulline malate (CM) has been shown to attenuate muscle soreness following intense exercise. Consuming CM increases nitric oxide production leading to increased blood flow, glucose and fatty acid metabolism, and muscle repair (Perez-Guisado and Jakeman, 2010). What has yet to be shown is the impact of CM consumption on the restoration of muscle function. PURPOSE: To examine the effects of CM supplementation on muscle soreness, pressure pain threshold (PPT), and contractile function. METHODS: Thirty women participated in this study. This study used a double-blind, matched-pairs design. Participants were randomly assigned to a CM or a placebo (PL) group. The participants completed four sessions. On day 1, participants completed an informed consent, a muscle soreness questionnaire (MSQ) focusing on their right calf, were assessed for pressure pain threshold (PPT) of the calf, and were assessed for plantar flexion (PF) contractile function using a Biodex isokinetic dynamometer at 1.05 rad/sec and at 3.14 rad/sec. Participants then consumed either 7g CM or a PL. One hour after consuming the supplement, participants completed a step protocol to induce muscle soreness. The protocol involved seven sets of stepping lasting 5 minutes each with a 1 minute rest between sets. Sessions 2-4 occurred at 24, 48, and 72 hours post-stepping. Sessions 2-4 were identical. Participants completed a MSQ, were assessed for PPT, and were measured for plantar flexion contractile function. Gain scores were calculated and analyzed using an ANOVA. RESULTS: Differences were seen for peak torque (CM: 12.7±12.6%; PL: -29.0±9.1%; p=.01); for average power (CM: 45.8±27.4%; PL: -17.2±15.7%; p=.05); and for total work (CM: 28.3±24.9%; PL: -31.1±10.1%; p=.04) at 3.14 rad/sec at 72 H post-stepping. No differences were seen in contractile function between CM and PL at 1.05 rad/sec (p>.05). No differences were seen for MSQ and PPT between CM and PL (p>.05). CONCLUSIONS: While it appears that CM supplementation in this dosing may not attenuate muscle soreness, it may be an effective strategy to recover muscle contractile function following the onset of mild DOMS. The reported vasodilating capabilities of CM may have facilitated muscle recovery by allowing nutrients to reach the muscle more effectively.