Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery

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Clifford, Tom ; Allerton, Dean ; Brown, Meghan ; Harper, Liam ; Horsburgh, Steven ; Keane, Karen ; Stevenson, Emma ; Howatson, Glyn (2017)
  • Publisher: NRC Research Press
  • Related identifiers: doi: 10.1139/apnm-2016-0525
  • Subject: RC1200 | GV1060_Track | GV557_Sports | C600 | QP
    mesheuropmc: human activities

This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle\ud damage following a marathon. Using a double blind, independent group’s design, 34 runners\ud (~16 previous marathons completed) consumed either BTJ or an isocaloric placebo (PLA) for\ud 3 days following a marathon. Maximal isometric voluntary contractions (MIVC),\ud countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine\ud kinase (CK), high sensitivity C-reactive protein (hs-CRP) and aspartate aminotransferase\ud (AST) were measured pre, post, and on the 2 days after the marathon. CMJ and MIVC were\ud reduced after the marathon (P<0.05) but no group differences were observed (P>0.05).\ud Muscle soreness was increased in the day after the marathon (BTJ; 45±48 vs. PLA; 46±39\ud mm) and had returned to baseline by day 2, irrespective of supplementation (P=0.694).\ud Cytokines (Interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased\ud immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post.\ud No interaction effects were evident for IL-6 (P=0.213). Leucocytes increased 1.7 fold after\ud the race and remained elevated 2 days post, irrespective of supplement (P<0.0001). CK\ud peaked at 1 day post marathon (BTJ: 965±967 & PLA: 1141±979 IU·L-1) and like AST and\ud hs-CRP, was still elevated 2 days after the marathon (P<0.05); however, no group differences\ud were present for these variables. Beetroot juice did not attenuate inflammation or reduce\ud muscle damage following a marathon, possibly because most of these indices were not\ud markedly different from baseline values in the days after the marathon.
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