Acute Postexercise Effects of Concentric and Eccentric Exercise on Glucose Tolerance

Impaired glucose tolerance was shown to be present 48 hr following muscle-damaging eccentric exercise. We examined the acute effect of concentric and muscle-damaging eccentric exercise, matched for intensity, on the responses to a 2-hr 75-g oral glucose tolerance test (OGTT). Ten men (27 +/- 9 years, 178 +/- 7 cm, 75 +/- 11 kg, (V) over dot O(2)max: 52.3 +/- 7.3 ml.kg(-1).min(-1)) underwent three OGTTs after an overnight 12 hr fast: rest (control), 40-min (5 x 8-min with 2-min interbout rest) of concentric (level running, 0%, CON) or eccentric exercise (downhill running, -12%, ECC). Running intensity was matched at 60% of maximal metabolic equivalent. Maximal isometric force of m. quadriceps femoris of both legs was measured before and after the running protocols. Downhill running speed was higher (level: 9.7 +/- 2.1, downhill: 13.8 +/- 3.2 km.hr(-1), p < .01). Running protocols had similar (V) over dot O(2)max (p = .59), heart rates (p = .20) and respiratory exchange ratio values (p = .74) indicating matched intensity and metabolic demands. Downhill running resulted in higher isometric force deficits (level: 3.0 +/- 6.7, downhill: 17.1 +/- 7.3%, p < .01). During OGTTs, area-under-the-curve for plasma glucose (control: 724 +/- 97, CON: 710 +/- 77, ECC: 726 +/- 72 mmol.L-1.120 min, p = .86) and insulin (control: 24995 +/- 11229, CON: 23319 +/- 10417, ECC: 21842 +/- 10171 pmol.L-1.120 min, p = .48), peak glucose (control: 8.1 +/- 1.3, CON: 7.7 +/- 1.2, ECC: 7.7 +/- 1.1 mmol.L-1, p = .63) and peak insulin levels (control: 361 +/- 188, CON: 322 +/- 179, ECC: 299 +/- 152 pmol.L-1, p = .30) were similar. It was concluded that glucose tolerance and the insulin response to an OGTT were not changed immediately by muscle-damaging eccentric exercise.