Effects of prior exercise on eccentric exercise-induced neutrophilia and enzyme release
Purpose: The purpose of this study was to determine the effects of prior exercise on changes in circulating neutrophils, neutrophil activation, and myocellular enzymes following a standardized bout of eccentric exercise. Methods: Twenty-four male volunteers were randomized into three groups (N = 8). Group C performed 10 sets of 10 eccentric contractions of the quadriceps muscles with both legs (100% of the concentric 1RM). Group D and Group F exercised for 2 h at 56%V̇O(2max) on a cycle ergometer followed by a similar bout of eccentric contractions. Group F also received 7.5 mL·kg-1 of a carbohydrate-electrolyte beverage every 30 min during the submaximal exercise, whereas group D received no fluid. Results: Body weight remained unchanged in groups C and F and decreased in group D by 1.56 ± 0.34 kg. Ultrastructural Z-Band damage increased three-fold following exercise and remained elevated 3 d after exercise but was not different among groups. Circulating neutrophils were elevated more in group D compared with those in group C immediately after the exercise or rest period, and this difference persisted 3 h after the eccentric exercise. Serum lactoferrin concentrations increased 3.3-fold after exercise in all groups (P < 0.01). Creatine kinase levels (CK) rose in all subjects, with subjects in Group F and D having a significantly greater rise in CK after exercise compared with those in group C. Conclusions: These data indicate that submaximal exercise followed by a bout of eccentric exercise results in similar amounts of myofibrillar injury with a larger neutrophil response and CK release.
Fielding, RA; Violan, MA; Svetkey, L; Abad, LW; Manfredi, TJ; Cosmas, A; Bean, J
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