Therapeutic Actions EXERCISE Cycling

NCBI pubmed

Caffeine increases both total work performed above critical power and peripheral fatigue during a 4-km cycling time trial.

Caffeine increases both total work performed above critical power and peripheral fatigue during a 4-km cycling time trial. J Appl Physiol (1985). 2018 Feb 22;: Authors: Felippe LC, Ferreira GA, Learsi SK, Boari D, Bertuzzi R, Lima-Silva AE Abstract The link between total work performed above critical power (CP) and peripheral muscle fatigue during self-paced exercise is unknown. We investigated the influence of caffeine on the total work done above CP during a 4-km cycling time trial (TT), and the subsequent consequence on the development of central and peripheral fatigue. Nine cyclists performed three constant-load exercise trials to determine CP and two 4-km TT ~75 min after oral caffeine (5 mg·kg-1) or cellulose (placebo) ingestion. Neuromuscular functions were assessed before and 50 min after supplementation, and 1 min after TT. Oral supplementation alone had no effect on neuromuscular function (P>0.05). Compared to placebo, caffeine increased mean power output (~4%, P=0.01) and muscle recruitment (as inferred by EMG, ~17%, P=0.01), and reduced the time to complete the TT (~2%, P=0.01). Work performed above CP during the caffeine trial (16.7{plus minus}2.1 kJ) was significantly higher than during the placebo (14.7{plus minus}2.1 kJ, P=0.01). End-exercise decline in quadriceps twitch force (pre- to post-exercise decrease in twitch force at 1 and 10 Hz) was more pronounced after caffeine compared to placebo (121{plus minus}13 and 137{plus minus}14 N vs 146{plus minus}13 and 156{plus minus}11 N; P<0.05). There was no effect of caffeine on central fatigue. In conclusion, caffeine increases muscle recruitment which enables greater work performed above CP and higher end-exercise peripheral locomotor muscle fatigue. PMID: 29470151 [PubMed - as supplied by publisher]

The effect of pre-exercise ingestion of corinthian currant on endurance performance and blood redox status.

The effect of pre-exercise ingestion of corinthian currant on endurance performance and blood redox status. J Sports Sci. 2018 Feb 22;:1-9 Authors: Deli CK, Poulios A, Georgakouli K, Papanikolaou K, Papoutsis A, Selemekou M, Karathanos VT, Draganidis D, Tsiokanos A, Koutedakis Y, Fatouros IG, Jamurtas AZ Abstract The present study investigated the effect of Corinthian currant pre-exercise supplementation on metabolism, performance and blood redox status during, and after prolonged exercise. Eleven healthy participants (21-45y) performed a 90-min constant-intensity (60-70% VO2max) submaximal-trial, plus a time-trial (TT) to exhaustion (95% VO2max) after consuming an isocaloric (1.5g CHO/kg BM) amount of randomly assigned Corinthian currant or glucose-drink, or water (control). Blood was drawn at baseline, pre-exercise, 30min, 60min, 90min of submaximal-trial, post-TT, and 1h post-TT. Post-ingestion blood glucose (GLU) under Corinthian currant was higher compared with water, and similar compared with glucose-drink throughout the study. Respiratory quotient under Corinthian currant was similar with glucose-drink and higher than water throughout the submaximal trial. Accordingly, higher CHO and lower fat oxidation were observed under Corinthian currant compared with water. The TT performance was similar between Corinthian currant, glucose-drink and water. Redox status were similar under all three conditions. Reduced glutathione (GSH) declined while total antioxidant capacity (TAC) and uric acid increased during exercise. GSH and TAC returned to baseline, while uric acid remained increased the following 1h. Corinthian currant, although did not alter exercise-mediated redox status changes and performance, was equally effective to a glucose-drink in maintaining GLU levels during prolonged cycling. PMID: 29469654 [PubMed - as supplied by publisher]

Erratum: Gough et al (2017).

Erratum: Gough et al (2017). Int J Sport Nutr Exerc Metab. 2018 Feb 22;:1 Authors: Abstract In the article by Gough, L.A., Rimmer, S., Osler, C.J., & Higgins, M.F. (2017). Ingestion of sodium bicarbonate (NaHCO3) following a fatiguing bout of exercise accelerates postexercise acid-base balance recovery and improves subsequent high-intensity cycling time to exhaustion, International Journal of Sport Nutrition and Exercise Metabolism, 27(5), 429-438, doi: 10.1123/ijsnem.2017-0065 , we did not accurately reflect several content and layout corrections which were needed. These include: (a) The key for Figure 1 was erroneously included for Figure 3 (and not for Figure 1). (b) The abbreviation for PRE was missing from the Figure 1 key. (c) Figure 3 contained two indicators (+) which were not necessary. The online version of this article has been corrected. We sincerely apologize for these errors. PMID: 29468909 [PubMed - as supplied by publisher]

Relation between Peak Power Output in Sprint Cycling and Maximum Voluntary Isometric Torque Production.

Related Articles Relation between Peak Power Output in Sprint Cycling and Maximum Voluntary Isometric Torque Production. J Electromyogr Kinesiol. 2017 Aug;35:95-99 Authors: Kordi M, Goodall S, Barratt P, Rowley N, Leeder J, Howatson G Abstract From a cycling paradigm, little has been done to understand the relationships between maximal isometric strength of different single joint lower body muscle groups and their relation with, and ability to predict PPO and how they compare to an isometric cycling specific task. The aim of this study was to establish relationships between maximal voluntary torque production from isometric single-joint and cycling specific tasks and assess their ability to predict PPO. Twenty male trained cyclists participated in this study. Peak torque was measured by performing maximum voluntary contractions (MVC) of knee extensors, knee flexors, dorsi flexors and hip extensors whilst instrumented cranks measured isometric peak torque from MVC when participants were in their cycling specific position (ISOCYC). A stepwise regression showed that peak torque of the knee extensors was the only significant predictor of PPO when using SJD and accounted for 47% of the variance. However, when compared to ISOCYC, the only significant predictor of PPO was ISOCYC, which accounted for 77% of the variance. This suggests that peak torque of the knee extensors was the best single-joint predictor of PPO in sprint cycling. Furthermore, a stronger prediction can be made from a task specific isometric task. PMID: 28624688 [PubMed - indexed for MEDLINE]

Dose effects of New Zealand blackcurrant on substrate oxidation and physiological responses during prolonged cycling.

Related Articles Dose effects of New Zealand blackcurrant on substrate oxidation and physiological responses during prolonged cycling. Eur J Appl Physiol. 2017 Jun;117(6):1207-1216 Authors: Cook MD, Myers SD, Gault ML, Edwards VC, Willems MET Abstract PURPOSE: It has been previously shown that New Zealand blackcurrant (NZBC) extract increased fat oxidation during short duration cycling. The present study examined the effect of different doses of NZBC extract on substrate oxidation and physiological responses during prolonged cycling. METHODS: Using a randomized counterbalanced Latin-square design, 15 endurance-trained male cyclists (age: 38 ± 12 years, height: 187 ± 5 cm, body mass: 76 ± 10 kg, [Formula: see text]: 56 ± 8 mL kg-1 min-1, and mean ± SD) completed four separate 120-min cycling bouts at 65% [Formula: see text] after ingesting no dose, or one of three doses (300, 600, or 900 mg day-1) of NZBC extract (CurraNZ™) for 7 days. RESULTS: A dose effect (P < 0.05) was observed for average fat oxidation (0, 300, 600, and 900 mg day-1 values of 0.63 ± 0.21, 0.70 ± 0.17, 0.73 ± 0.19, and 0.73 ± 0.14 g min-1) and carbohydrate oxidation (0, 300, 600, and 900 mg day-1 values of 1.78 ± 0.51, 1.65 ± 0.48, 1.57 ± 0.44, and 1.56 ± 0.50 g min-1). The individual percentage change of mean fat oxidation was 21.5 and 24.1% for 600 and 900 mg day-1 NZBC extract, respectively, compared to no dose. Heart rate, [Formula: see text], [Formula: see text], plasma lactate, and glucose were not affected. CONCLUSION: Seven-day intake of New Zealand blackcurrant extract demonstrated a dose-dependent effect on increasing fat oxidation during 120-min cycling at 65% [Formula: see text] in endurance-trained male cyclists. PMID: 28391393 [PubMed - indexed for MEDLINE]