Fibre-type-specific and Mitochondrial Biomarkers of Muscle Damage after Mountain Races

Abstract

ABstR AC tConsequences of running mountain races on muscle damage were investigated by analysing serum muscle enzymes and fibre-type-specific sarcomere proteins. We studied 10 trained amateur and 6 highly trained runners who ran a 35 km and 55 km mountain trail race (MTR), respectively. Levels of creatine kinase (CK), CK-MB isoform (CK-MB), sarcomeric mitochondrial CK (sMtCK), transaminases (AST and ALT), cardiac troponin I (cTnI) and fast (FM) and slow myosin (SM) isoforms, were assessed before, 1 h, 24 h and 48 h after the beginning of MTR. Significant SM increases were found at 24 h in the 55 km group. Levels of CK, CK-MB, AST and cTnI were significantly elevated in both groups following MTR, but in the 55 km group they tended to stabilize in at 48 h. Using pooled data, timeindependent serum peaks of SM and CK-MB were significantly correlated. Moreover, concentration of sMtCK was significantly elevated at 1 and 24 h after the race in the 35 km group. Although training volume could confer protection on the mitochondria, the increase in serum CK-MB and SM in the 55 km group might be related to damage to the contractile apparatus type I fibres. Competing in long-distance MTRs might be related to deeper type I muscle fibre damage, even in highly trained individuals

Broad Spectrum Polyphenol Supplementation from Tart Cherry Extract on Markers of Recovery from Intense Resistance Exercise

“…One variable not measured in prior polyphenol research, but has been assessed in other antioxidant literature, is creatine kinase myocardial band (CK-MB), a marker typically associated with cardiac damage [ 5 ] that has recently been proposed as a marker specifically for type I muscle fiber damage [ 18 ]. An increase in CK-MB is a typical response to exercise and is associated with the structural disruption of muscle fibers and the leaking of the contents on these fibers into the plasma [ 5 ].…”

Broad Spectrum Polyphenol Supplementation from Tart Cherry Extract on Markers of Recovery from Intense Resistance Exercise

“…Although other polyphenol containing supplements such as blackcurrant juice (23) have demonstrated a reduction in skeletal muscle damage, this has not been previously shown in the tart cherry supplementation studies. In addition to skeletal muscle damage, this study assessed a marker of cardiac muscle damage (5), CKMB which was recently identi ed as a potential marker of type I muscle ber damage (18). While CKMB has been shown to decrease in the presence of other antioxidants, such as vitamin E (20) and Allopurinol (19), this study provides evidence that the compounds and fractions in tart cherries, including polyphenols, may have the same effect.…”

“…One variable not measured in prior polyphenol research, but has been assessed in other antioxidant literature, is creatine kinase myocardial band (CK-MB), a marker typically associated with cardiac damage (5) that has recently been proposed as a marker speci cally for type I muscle ber damage (18). An increase in CK-MB is a typical response to exercise and is associated with the structural disruption of muscle bers and the leaking of the contents on these bers into the plasma (5).…”

“…An increase in CK-MB is a typical response to exercise and is associated with the structural disruption of muscle bers and the leaking of the contents on these bers into the plasma (5). Strenuous exercise, such as long distance running (18), professional soccer (19) and also resistance exercise (5) signi cantly increases CK-MB. These increases have been attenuated by other antioxidant supplements, such as Vitamin E under hypoxic conditions (20) and the drug Allopurinol (19), and thus antioxidants could potentially enhance recovery from strenuous exercise in the context of CK-MB.…”

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“…It has to be pointed out that the skeletal muscle also expresses CK-MB but in small quantities. 57 Therefore, it could not be ruled out that the observed CK-MB elevation was due to deteriorations of the skeletal muscle. In consequence, we also measured the highly heart-specific hsTnT.…”