The effects of carbohydrate (CHO) supplementation on muscle glycogen and resistance exercise performance were examined with eight highly resistance trained males (mean ± SEM, age: 24.3 ± 1.1 years, height: 171.9±2.0 cm, body mass: 85.7 ± 3.5 kg; experience 9.9 ± 2.0 years). Subjects participated in a randomized, double blind protocol with testing sessions separated by 7 days. Testing consisted of an initial isokinetic leg exercise before and after an isotonic resistance exercise (IRT) session consisting of 3 leg exercises lasting ~39 min. Subjects consumed a CHO (1.0 g CHO ·kg body mass−1) or placebo treatment (PLC), prior to and every 10-min (0.5 g CHO ·kg body mass−1) during the IRT. Muscle tissue was obtained from the m vastus lateralis after a supine rest (REST) immediately after the initial isokinetic test (POST-ISO) and immediately after the IRT (POST-IRT). The CHO treatment elicited significantly less muscle glycogen degradation from the POST-ISO to POST-IRT (126.9 ± 6.5 to 109.7 ± 7.1 mmol·kg wet weight−1) compared to PLC (121.4±8.1 to 88.3±6.0 mmol·kg wet weight−1). There were no differences in isokinetic performance between the treatments. The results of this investigation indicate that the consumption of a CHO beverage can attenuate the decrease in muscle glycogen associated with isotonic resistance exercise but does not enhance the performance of isokinetic leg exercise.
G. Gregory Haff, Alexander J. Koch, Jeffrey A. Potteiger, Karen E. Kuphal, Lawrence M. Magee, Samuel B. Green and John J. Jakicic
Kevin Allen Jacobs and W. Michael Sherman
Carbohydrate (CHO) is the body's most limited fuel and the most heavily metabolized during moderate-intensity exercise. For this reason it is recommended that endurance athletes consume a high-CHO diet (8-10 g CHO ⋅ kg body weight−1 ⋅ day−1) to enhance training and performance. A review of the literature supports the benefits of CHO supplementation on endurance performance. The benefits of chronic high-CHO diets on endurance performance are not as clear. Recent evidence suggests that a high-CHO diet may be necessary for optimal adaptations to training. However, the paucity of data in this area precludes any concrete conclusions. The practicality of high-CHO diets is not well understood. The available evidence would indicate that a high-CHO diet is the best dietary recommendation for endurance athletes.
Mark D. Haub, Jeffrey A. Potteiger, Dennis J. Jacobsen, Karen L. Nau, Lawrence A. Magee and Matthew J. Comeau
We investigated the effects of carbohydrate ingestion on glycogen replenishment and subsequent short duration, high intensity exercise performance. During Session 1, aerobic power was determined and each subject (N = 6) was familiarized with the 100-kJ cycling test (lOOKJ-Test). During the treatment sessions, the subjects performed a lOOKJ-Test (Ride-1), then consumed 0.7 g ⋅ kg body mass-1 of maltodextrin (CHO) or placebo (PLC), rested 60 min, and then performed a second lOOKJ-Test (Ride-2). Muscle tissue was collected before (Pre-1) and after Ride-1 (Post-1), and before (Pre-2) and after Ride-2 (Post-2), and analyzed for glycogen concentration. Both treatments yielded a significant increase in glycogen levels following the 60-min recovery, but there was no difference between treatments. Time to complete the lOOKJ-Test increased significantly for PLC, but not for CHO. These data indicate that the decrease in performance during Ride-2 in PLC was not the result of a difference in glycogen concentration.
Andrzej Gawrecki, Aleksandra Araszkiewicz, Agnieszka Szadkowska, Grzegorz Biegański, Jan Konarski, Katarzyna Domaszewska, Arkadiusz Michalak, Bogda Skowrońska, Anna Adamska, Dariusz Naskręt, Przemysława Jarosz-Chobot, Agnieszka Szypowska, Tomasz Klupa and Dorota Zozulińska-Ziółkiewicz
There is limited data concerning the glycemic changes during mass sporting competitions for children and youth with diabetes. In general, aerobic exercise is associated with decreasing glucose values, whereas brief, very high-intensity or anaerobic exercise is related to increasing glucose values
Yuri Alberto Freire, Geovani de Araújo Dantas de Macêdo, Rodrigo Alberto Vieira Browne, Luiz Fernando Farias-Junior, Ágnes Denise de Lima Bezerra, Ana Paula Trussardi Fayh, José Cazuza de Farias Júnior, Kevin F. Boreskie, Todd A. Duhamel and Eduardo Caldas Costa
light physical activity can reduce postprandial glucose, insulin, triglycerides, and blood pressure (BP) levels. 8 – 12 These benefits seem to be less robust in individuals without cardiometabolic risk factors or diseases. 9 , 10 Inconsistent results have been reported in young healthy adults
Alaaddine El-Chab and Miriam E. Clegg
avoid vigorous exercise on the morning of the test, as it has been shown to raise whole-body glucose uptake and glucose area under the curve (GAUC; Rose et al., 2001 ). This will result in an increase in coefficient of variation (CV) between trials and possibly exceed the acceptable level of
Keith Tolfrey, Julia Kirstey Zakrzewski-Fruer and Alice Emily Thackray
Citation 1 Fletcher EA, Salmon J, McNaughton SA, et al. Effects of breaking up sitting on adolescents’ postprandial glucose after consuming meals varying in energy: a cross-over randomised trial. J Sci Med Sport . E-pub ahead of print. doi: 10.1016/j.jsams.2017.06.002 Objectives : To explore the
Stephen A. Mears, Kathryn Dickinson, Kurt Bergin-Taylor, Reagan Dee, Jack Kay and Lewis J. James
subject sat for 5 minutes, and resting HR was recorded. At the end of the rest period, a capillary fingertip blood sample (20 µL) was collected and later analyzed for whole blood lactate and glucose concentrations. Subjects were also asked to rate their gastrointestinal (GI) comfort (1 = neutral and 12
Emily Arentson-Lantz, Elfego Galvan, Adam Wacher, Christopher S. Fry and Douglas Paddon-Jones
, 1999 ; Suesada, Martins, & Carvalho, 2007 ). Investigators recently demonstrated that reducing and limiting step count to 1413 ± 110 steps/day for 14 days had a negative effect on myofibrillar protein synthesis, lean leg mass, and glucose tolerance in a cohort of free-living, healthy older adults
Alexei Wong, Marcos A. Sanchez-Gonzalez, Won-Mok Son, Yi-Sub Kwak and Song-Young Park
the study. Blood Sampling and Analysis Venous blood samples were obtained from an antecubital vein around 8 AM following an overnight fast. Blood glucose was measured using an automated analyzer (120-FR; Toshiba, Tokyo, Japan). Blood was centrifuged and stored at −80°C for future analysis. To assess