Original articles   

The Journal of Sports Medicine and Physical Fitness 2001 June;41(2):216-22

Copyright © 2002 EDIZIONI MINERVA MEDICA

language: English

The effects of supplemental carbohydrate ingestion on intermittent isokinetic leg exercise

Haff G. G., Schroeder C. A., Koch A. J., Kuphal K. E., Comeau M. J., Potteiger J. A.

From the * Exercise Physiology Laboratory Appalachian State University, Boone, NC, USA and the Exercise Physiology Laboratory University of Kansas, Lawrence, KS, USA

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°·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.