EFFECTS OF CROSS TRAINING ON MARKERS OF INSULIN-RESISTANCE HYPERINSULINEMIA

This study examined, through a randomized controlled trial, the effect s of cross-training (combined resistance and endurance exercise) on ma rkers of insulin resistance, (e.g., dyslipidemia, intra-abdominal obes ity, hyperinsulinemia, and hypertension), body composition, and perfor mance in hyperinsulinemic individuals. Sedentary adult males character ized as hyperinsulinemic (fasting insulin > 2 OuU.mL(-1)), randomly as signed to two groups (N = 8 each), completed 14 wk of training at 3 d. wk(-1), An endurance-only (E) group performed both continuous cycle ex ercise and walking (30 min each at 60-70% heart rate reserve). A cross -training (C) group performed both endurance and resistance exercise ( 8 exercises, 4 sets/exercise, 8-12 repetitions/set) in a single sessio n. Both E and C groups demonstrated similar increases in VO2max (25% a nd 27%) while only C demonstrated an increase in 1 RM bench press (19% ) and leg press (25%). The changes induced by C training were signific antly greater than those from E training alone in percent fat (6.9 +/- 1.3 vs 1.4 +/- 1.4), insulin concentration (8.5 +/- 2.7 vs 3.0 +/- 1. 3 uU.mL(-1)), glucose levels (11.1 +/- 2.9 vs 5.9 +/- 2.6 mg.dL(-1)), HDL-C levels (5.1 +/- 1.3 vs 2.9 +/- 1.6 mg.dL(-1)), triglyceride conc entration (43.5 +/- 13.6 mg.dL(-1)), and systolic blood pressure (14.6 +/- 5.5 vs 8.3 +/- 6.8 mm Hg). Results indicate that the addition of resistance training to an endurance training program will induce signi ficantly greater differences in markers of insulin resistance and body composition in individuals with hyperinsulinemia than endurance train ing alone.