The effects of supplemental carbohydrate ingestion on intermittent isokinetic leg exercise.

BACKGROUND The purpose of this investigation was to examine the effects of carbohydrate (CHO) supplementation on isokinetic leg extension/flexion exercise performance, blood glucose responses, blood free fatty acid (FFA) responses, and blood lactate (La) responses. METHODS Eight resistance trained males (mean+/-SEM, age: 23.7+/-1.3 yrs, height: 180.0+/-3.5 cm, bodymass: 94.9+/-4.9 kg) participated in a randomized, double blind protocol with testing sessions separated by 7-d. Subjects were given CHO or placebo (P) while performing 16 sets of 10 repetitions at 120 degrees x s(-1) on a Cybex isokinetic dynamometer. Performance variables measured were; total work (TW), average work (AW), peak torque (PT) and average torque (AT). Plasma glucose (PG), FFA, and La were measured prior to testing (PRE), after set 8 (MID), and 16 (POST). RESULTS Results indicated that the CHO treatment elicited significantly (p<0.05) more TW (CHO: 41.1+/-3.9 kJ; P: 38.1+/-3.9 kJ) and AW (CHO: 2.6+/-0.2 kJ; P: 2.4+/-0.2 kJ). There were no differences (p<0.05) between treatments for PT of the hamstrings (CHO: 91.6+/-6.5 Nm; P: 87.4+/-8.5 Nm) and quadriceps (CHO: 129.7+/-9.5 Nm; P: 123.0+/-10.6 Nm). The AT of the hamstrings (CHO: 77.8+/-5.2 Nm; P: 75.7+/-8.7 Nm) and quadriceps (CHO: 116.9+/-8.9 Nm; P: 110.0+/-8.5 Nm) were not statistically different (p>0.05) between the treatments. PG was significantly higher at the POST blood draw in the CHO treatment. No significant differences (p>0.05) were observed between the treatments for FFA and La concentrations. CONCLUSIONS The data from this investigation indicate that the use of CHO supplementation during isokinetic leg exercise allows for the performance of more work.