title: Effects of carbohydrate supplementation on force output and time to exhaustion during static leg contractions superimposed with electromyostimulation.
abstract: The purpose of this study was to investigate the effects of carbohydrate ingestion on force output and time to exhaustion using single leg static contractions superimposed with brief periods of electromyostimulation. Six trained male subjects participated in a randomized, counterbalanced, double-blind study. The subjects were randomly assigned to placebo (PL) or carbohydrate (CHO). The subjects in CHO consumed 1 g of carbohydrate per kilogram of body mass loading dose and 0.17 g of carbohydrate per kilogram of body mass every 6 minutes during the exercise protocol. The PL received an equal volume of a solution made of saccharin and aspartame. The exercise protocol consisted of repeated 20-second static contractions of quadriceps muscle at 50% maximal voluntary contraction followed by 40-second rest until failure occurred. Importantly, the force output during quadriceps maximal voluntary contraction strength with superimposed electromyostimulation was measured in the beginning and every 5 minutes during the last 3 seconds of static contractions throughout the exercise protocol. Venous blood samples were taken preexercise, immediately postexercise, and at 5 minutes postexercise and analyzed for blood lactate. Our results indicate that time to exhaustion (PL = 16.0 ± 8.1 minutes; CHO = 29.0 ± 13.1 minutes) and force output (PL = 3,638.7 ± 524.5 N; CHO = 5,540.1 ± 726.1 N) were significantly higher (p < 0.05) in CHO compared with that in PL. Data suggest that carbohydrate ingestion before and during static muscle contractions can increase force output and increase time to exhaustion. Therefore, our data suggest that carbohydrate supplementation before and during resistance exercise might help increase the training volume of athletes.
authors.affiliation: Department of Kinesiology, Mississippi State University, Mississippi State, Mississippi, USA. bw244@msstate.edu
authors.forename: Benjamin
authors.initials: B
authors.lastname: Wax
authors.forename: Stanley P
authors.initials: SP
authors.lastname: Brown
authors.forename: Heather E
authors.initials: HE
authors.lastname: Webb
authors.forename: Andreas N
authors.initials: AN
authors.lastname: Kavazis
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002241:Carbohydrates / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005221:Fatigue; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D007866:Leg / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology; D052097:Quadriceps Muscle / Q000187:drug effects* / Q000502:physiology; D004561:Transcutaneous Electric Nerve Stimulation
chemical_list: D002241:Carbohydrates; D019344:Lactic Acid