The effect of a breakfast’s glycaemic index and type of hydration on metabolism and cycling performance: a crossover, randomized, controlled clinical trial. [El efecto del índice glucémico del desayuno y el tipo de hidratación en el metabolismo y el rendimiento del ciclismo: un ensayo clínico cruzado, aleatorizado y controlado].

The purpose of this study was to compare the effect of the glycaemic index of breakfast on metabolic parameters and performance of cyclists with different types of hydration (water or isotonic beverage). Twelve male recreational cyclists participated in four experimental trials where they consumed either a high glycaemic index (HGI) or low glycaemic index (LGI) meal, 30 min before exercise on a cycle ergometer. Exercise was performed at 70% maximal oxygen uptake for 90 min followed by a 6 km performance. During each trial, 3 mL.kg-1 body mass of either water or isotonic beverage was provided. The postprandial glycaemic response and areas under the blood glucose curve 30 min after ingestion were higher after the consumption of the HGI meals than that after the consumption of the LGI meals. The glycaemic response and carbohydrate oxidation during the trials with isotonic beverage consumption were higher than that in trials with water consumption during exercise (p<0.05). There was no significant difference on exercise performance among all trials (p=0.409). This study demonstrated that, despite significant metabolic changes, neither LGI nor HGI meals consumed for breakfast, 30 min before exercise on a cycle ergometer, affect subsequent cycling performance.

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Glycaemic potency reduction by coarse grain structure in breads is largely eliminated during normal ingestion

British Journal Of Nutrition ◽

10.1017/s000711452100252x ◽

2021 ◽

pp. 1-27

Author(s):

Akila SRV ◽

Suman Mishra ◽

Allan Hardacre ◽

Lara Matia-Merino ◽

Kelvin Goh ◽

...

Keyword(s):

Blood Glucose ◽

Glycaemic Index ◽

Moderating Effect ◽

Grain Structure ◽

Coarse Grain ◽

White Bread ◽

Starch Digestion ◽

Glycaemic Response ◽

Significant Difference

Abstract The hypothesis that coarse grain particles in breads reduce glycaemic response only if the particles remain intact during ingestion was tested. Three breads were formulated: (1) White bread (WB - reference), (2) 75% of kibbled purple wheat in 25% white bread matrix (PB), (3) a 1:1 mixture of 37.5% kibbled soy beans and 37.5% of kibble purple wheat in 25% white bread matrix (SPB). Each bread was ingested in three forms: unchewed (U), as customarily consumed (C), and homogenized (H). Twelve participants ingested 40 g available carbohydrate portions of each bread in each form, with post prandial blood glucose measured over 120 min. Glycaemic responses to WB were the same regardless of its form when ingested. Unchewed PB had significantly less glycaemic effect than WB, whereas the C and H forms were similar to WB. Based on a glycaemic index (GI) of 70 for WB the GI values for the C, U and H breads respectively were WB: 70.0, 70, 70, PB: 75, 42, 61, SPB: 57, 48, 55 (%) (Least significant difference = 17.43, p <0.05, bold numbers significantly different from WB). The similar glycaemic response to the H and C forms of the breads, and their difference from the U form, showed that the glycaemia-moderating effect of grain structure on starch digestion was lost during customary ingestion of bread. We conclude that kibbled grain structure may not effectively retard starch digestion in breads as normally consumed because it is largely eliminated by ingestive processes including chewing.

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An Isocaloric Glucose-Fructose Beverage’s Effect on Simulated 100-km Cycling Performance Compared With a Glucose-Only Beverage

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.20.2.122 ◽

2010 ◽

Vol 20 (2) ◽

pp. 122-131 ◽

Cited By ~ 40

Author(s):

Darren Triplett ◽

J. Andrew Doyle ◽

Jeffrey C. Rupp ◽

Dan Benardot

Keyword(s):

Time Trial ◽

Endurance Performance ◽

Cycling Performance ◽

Peak Oxygen Uptake ◽

Cycle Ergometer ◽

Oxidation Rates ◽

Familiarization Trial ◽

Competitive Cyclists ◽

Experimental Trials ◽

Time Point

A number of recent research studies have demonstrated that providing glucose and fructose together in a beverage consumed during exercise results in significantly higher oxidation rates of exogenous carbohydrate (CHO) than consuming glucose alone. However, there is insufficient evidence to determine whether the increased exogenous CHO oxidation improves endurance performance. The purpose of this study was to determine whether consuming a beverage containing glucose and fructose (GF) would result in improved cycling performance compared with an isocaloric glucose-only beverage (G). Nine male competitive cyclists (32.6 ± 5.8 years, peak oxygen uptake 61.5 ± 7.9 ml · kg-1 · min-1) completed a familiarization trial and then 2 simulated 100-km cycling time trials on an electronically braked Lode cycle ergometer separated by 5–7 d. During the randomly ordered experimental trials, participants received 36 g of CHO of either G or GF in 250 ml of water every 15 min. All 9 participants completed the 100-km time trial significantly faster when they received the GF beverage than with G (204.0 ± 23.7 vs. 220.6 ± 36.6 min; p = .023). There was no difference at any time point between trials for blood glucose or for blood lactate. Total CHO oxidation increased significantly from rest during exercise but was not statistically significant between the GF and G trials, although there was a trend for CHO oxidation to be higher with GF in the latter stages of the time trial. Consumption of a CHO beverage containing glucose and fructose results in improved 100-km cycling performance compared with an isocaloric glucose-only beverage.

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Factors contributing to increased muscle fatigue with β-blockers

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y91-039 ◽

1991 ◽

Vol 69 (2) ◽

pp. 254-261 ◽

Cited By ~ 5

Author(s):

R. S. McKelvie ◽

N. L. Jones ◽

G. I. F. Heigenhauser

Keyword(s):

Muscle Fatigue ◽

Exercise Performance ◽

Cycle Ergometer ◽

Metabolic Effects ◽

High Dose ◽

Exercise Tests ◽

Significant Difference ◽

Ergometer Exercise ◽

The Relationship ◽

Male Subjects

β-Adrenoceptor blockers are widely used clinically and can be classified as nonselective (β1 and β2) or selective (β1). Impairment of exercise performance is a well-known side effect of this group of drugs. This paper reviews mechanisms that could potentially be responsible for this impairment. In addition to cardiovascular and metabolic effects, β -blockade inhibits Na+–K+ ATPase pumps controlling ion movement between muscle and plasma and thus may contribute to muscle fatigue through this mechanism. To investigate the relationship between the change in plasma [K+] and exercise performance, we studied healthy male subjects taking propranolol. Eight subjects performed maximal incremental cycle ergometer exercise tests during control (no drug), low dose (LD) (40 mg daily), and high dose (HD) (265 ± 4.3 (SE) mg daily) of propranolol. The control plasma [K+] (5.8 ± 0.12 mequiv./L) during exercise was significantly lower than either the LD (6.4 ± 0.05 mequiv./L) or HD (6.1 ± 0.16 mequiv./L) values. There was no significant difference between plasma [K+] for the LD and HD of propranolol. However, maximum oxygen uptake was reduced only while taking the HD of propranolol. Six of the subjects also performed three 30-s bouts of high intensity exercise on an isokinetic cycle ergometer while taking the LD and HD of propranolol. There was no significant difference between doses for the increase in plasma [K+] (LD, 7.8 ± 0.35 mequiv./L vs. HD, 7.6 ± 0.36 mequiv./L) during exercise. However, exercise performance was significantly reduced during HD compared with LD. These results suggest that the increases in plasma [K+] with propranolol did not play a direct significant role in the reduced performance observed during the HD.Key words: exercise, potassium, performance, lactate.

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Efecto del ejercicio cardiovascular sobre el autoconcepto en adultos mayores: ensayo clínico

Enfermería Global ◽

10.6018/eglobal.403851 ◽

2020 ◽

Vol 19 (4) ◽

pp. 145-169

Author(s):

Erick Landeros-Olvera ◽

Joaquín Gil-Benitez ◽

Claudia Sosa-Rodríguez ◽

Rosa María Galicia-Aguilar ◽

Natalia Ramírez-Girón

Keyword(s):

Self Concept ◽

Control Group ◽

Controlled Clinical Trial ◽

Significant Difference ◽

Las Mujeres ◽

Musculoskeletal Function ◽

And Control ◽

Los Grupos ◽

Experimental Group ◽

Ensayo Clínico

Objetivo: Describir el efecto de una dosis de ejercicio gradual y progresiva de bajo impacto cardiovascular sobre el autoconcepto físico en un grupo de adultos mayores.Métodos: Ensayo Clínico Aleatorizado y Controlado con intervención simple ciego en dos grupos equivalentes (experimental y control), bajo un modelo de mediciones repetidas. La muestra estuvo compuesta por 20 sujetos por grupo. Se seleccionaron adultos mayores de 60 a 70 años, de ambos sexos, sin riesgo cardiaco; se excluyeron adultos mayores con patologías que pudieran causar limitaciones en la funcionalidad músculo-esquelética o cardiopulmonar. La intervención consistió en la realización de ejercicio de forma gradual y progresiva, 3 veces por semana durante 10 semanas. El indicador para evaluar el autoconcepto físico fue el Instrumento de Auto descripción (SDQ), con un patrón de respuesta tipo Likert.Resultados: Ingresaron 45 sujetos, grupo control 22 adultos (edad 66.6±6.14) y grupo experimental 23 adultos (edad 67.0±7.19); completaron el programa 38 adultos. En ambos grupos predominaron las mujeres (66.7%), nivel socioeconómico medio (73.3%) y escolaridad básica (44.6%). No existió diferencia significativa entre los grupos antes de la intervención, en contraste, después de la intervención existió diferencia significativa entre grupos, lo que resultó en un incremento del autoconcepto físico en el grupo experimental y un descenso del autoconcepto físico en el grupo control.Conclusión: La intervención de ejercicio controlado, gradual, progresivo y de bajo impacto cardiovascular, de tres sesiones por semana durante 10 semanas probó ser efectiva para aumentar el autoconcepto físico en el grupo experimental de adultos. Objective: To describe the effect of a dose of gradual and progressive exercise of low cardiovascular impact on physical self- concept in a group of seniors. Methods: Randomized, controlled clinical trial with a blinded experiment in two equivalent groups (experimental one and control one), under a repeated model of measures. The sample consisted of 20 individuals per group. Male and female seniors from 60 to 70 years old with no heart risk, were selected. Seniors with pathologies that could cause limitations on the musculoskeletal function cardiopulmonary functionality were excluded. The intervention consisted of performing exercise gradually and progressively, 3 times a week for 10 weeks. The indicator for assessing physical self-concept was the Self-Description Questionnaire (SDQ), with a Likert response pattern.Results: 45 individuals were taken; control group 22 adults (age 66.6 ± 6.14) and experimental group 23 adults (age 67.0 ± 7.19); 38 adults completed the program. In both groups, women predominated (66.7%), medium socioeconomic level (73.3%) and basic schooling (44.6%). There was no significant difference between the groups before the intervention, in contrast, after the intervention there was a significant difference between them, which resulted in an increase in physical self-concept in the experimental group and a decrease in physical self-concept in the control group.Conclusion: The intervention of controlled, gradual, progressive and low cardiovascular impact exercise of three sessions per week for 10 weeks proved to be effective in increasing physical self-concept in the experimental group of adults.

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Power-Velocity Characteristics and Jumping Abilities in Male Combat Athletes

Human Movement ◽

10.1515/humo-2016-0019 ◽

2016 ◽

Vol 17 (3) ◽

Cited By ~ 3

Author(s):

Krzysztof Buśko

Keyword(s):

External Force ◽

Cycle Ergometer ◽

Centre Of Mass ◽

Maximal Power ◽

Counter Movement Jump ◽

Significant Difference ◽

Ergometer Exercise ◽

Velocity Relationship ◽

Force Velocity ◽

External Loads

AbstractThe aim of the study was to examine differences in power-velocity characteristics, and the maximal power and height of rise of the body’s centre of mass, measured in the counter-movement jump (CMJ) and the spike jump (SPJ), between judoists, boxers and taekwondo athletes.The study involved 7 judoists, 6 boxers, and 6 taekwondo athletes. The maximal power and height of jump were measured at CMJ and SPJ jumps. Force-velocity and power-velocity relations were determined on the basis of 5 maximal cycle ergometer exercise bouts at increasing external loads of 2.5, 5.0, 7.5, 10.0, and 12.5% of body weight (BW).The absolute and relative power and velocity recorded for an external force-velocity relationship were similar in the groups. A significant difference was only observed between taekwondo athletes and judoists for absolute power at the external load of 2.5% BW (In martial arts, training and competition should affect physical characteristics, including jumping and power. The power and velocity recorded for an external force-velocity relationship were similar in the groups. Judoists and boxers did not differ in terms of power or height of the jumps. Taekwondo athletes developed the biggest power and height of the jumps. This is consistent with the discipline characteristics.

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Modification of Cooper’s 12-min Run Test to Predict Maximum Oxygen Uptake in Indian Cricketers

International Journal of Physical Education Fitness and Sports ◽

10.34256/ijpefs2029 ◽

2020 ◽

Vol 9 (2) ◽

pp. 72-78

Author(s):

Amit Bandyopadhyay

Keyword(s):

Oxygen Uptake ◽

Study Groups ◽

Cycle Ergometer ◽

Gas Analysis ◽

Maximum Oxygen Uptake ◽

Regression Equations ◽

Female Cricket ◽

Significant Difference ◽

Ergometer Exercise ◽

Run Test

Cooper’s 12-minute run test (CRT) for prediction of maximum oxygen uptake (VO2max) has not yet been explored in Indian sportspersons. Present investigation was conducted to evaluate the applicability of CRT in Indian cricketers. 75 male and 45 female cricket players were randomly recruited from reputed cricket academies of Kolkata, India and were randomly assigned into the study group (male = 45, female = 25) and confirmatory group (male = 30, female = 20). Incremental cycle ergometer exercise was used for direct estimation of VO2max by expired gas analysis and the indirect prediction of VO2max (PVO2max) was performed by CRT method. The current protocol of CRT was found to be inapplicable in both the genders of Cricketers due to a significant difference between PVO2max and VO2max and a large limit of agreement between PVO2max and VO2max in the study groups. A significant correlation (r = 0.76 in males and r = 0.79 in females, p<0.001) was depicted between VO2max and distance covered in CRT. Regression equations were computed based on the significant correlation. The application of these equations in the confirmatory groups revealed an insignificant difference between PVO2max and VO2max and narrow limits of agreement. Standard errors of the estimate of the regression norms were also minimal. Therefore, modified equations are recommended for CRT application for valid and precise evaluation of cardiorespiratory fitness in terms of VO2max in male and female Indian cricketers.

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Differentiation between the intensity of breathlessness and the distress it evokes in normal subjects during exercise

Clinical Science ◽

10.1042/cs0800065 ◽

1991 ◽

Vol 80 (1) ◽

pp. 65-70 ◽

Cited By ~ 75

Author(s):

Rachel C. Wilson ◽

P. W. Jones

Keyword(s):

Minute Ventilation ◽

Normal Subjects ◽

Cycle Ergometer ◽

Exercise Tests ◽

Distress Score ◽

Significant Difference ◽

Ergometer Exercise ◽

Wide Scatter ◽

The Subject ◽

The Mean

1. This study was designed to examine whether normal subjects could differentiate between the ‘intensity’ of their breathlessness and the amount of ‘distress’ it evoked, by specific wording of the instructions. 2. A preliminary study showed no significant difference between ‘distress’ score during exercise measured on two separate occasions (P = 0.3). 3. Ten subjects each performed two identical incremental cycle-ergometer exercise tests on separate occasions during which they were asked to quantify either ‘intensity’ or ‘distress’ by using modified Borg scales. 4. In all subjects there was a significant correlation (P <0.001) between ‘intensity’ and minute ventilation. In eight subjects there was a significant correlation (P <0.05) between ‘distress’ and minute ventilation. One subject displayed no significant correlation and one registered no distress. 5. Mean ‘intensity’ was greater than the mean ‘distress’ (P = 0.0001). The slope of ‘intensity’/minute ventilation was greater than the slope of ‘distress’/minute ventilation (P = 0.0001). 6. Within individuals there was a significant correlation beween ‘intensity’ and ‘distress’ (P <0.05). There was a wide scatter in the slope of this relationship between subjects and maximum ‘intensity’ and ‘distress’ did not correlate. 7. Different elements of the breathlessness sensation could be identified and selectively measured depending on the wording of the instructions given to the subject. 8. There was a wide intersubject variation in the magnitude of both breathlessness ‘intensity’ and ‘distress’ estimates, but the differences between subjects in these two components of the sensation did not appear to follow a common pattern.

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Glycaemic index of common foods tested in the UK and India

British Journal Of Nutrition ◽

10.1017/s0007114507831801 ◽

2007 ◽

Vol 99 (4) ◽

pp. 840-845 ◽

Cited By ~ 46

Author(s):

C. J. K. Henry ◽

H. J. Lightowler ◽

K. Newens ◽

V. Sudha ◽

G. Radhika ◽

...

Keyword(s):

Asian Indian ◽

Asian Indians ◽

Area Under The Curve ◽

Glycaemic Index ◽

Glycaemic Response ◽

Diabetes Susceptibility ◽

Significant Difference ◽

Finger Prick ◽

The Uk

The aim of this study was to ascertain whether international glycaemic index (GI) values, predominantly developed using peoples living in Europe, North America or Australia, are applicable to Asian Indians resident in their own country. Thirty-four Caucasian subjects were recruited in Oxford, UK and thirteen Asian Indian subjects in Chennai, India. Two types of sweet biscuits and three breakfast cereals were tested for glycaemic response in each group. Subjects were served equivalent available carbohydrate amounts (50 g) of test foods and a reference food (glucose), on separate occasions. Capillary blood glucose was measured from finger-prick samples in fasted subjects ( − 5 and 0 min) and at 15, 30, 45, 60, 90 and 120 min after starting to eat. For each test food, the incremental area under the curve (IAUC) and GI values were determined. Although the glycaemic response to the reference food was higher in Asian Indian subjects compared with UK Caucasian subjects (IAUC 219 mmol/min per litre v. 157 mmol/min per litre, respectively; P < 0·01), there was no significant difference in GI values of the five test foods between the two groups. This is the first study known to the authors to examine the role of ethnicity on GI when the subjects are resident in their own countries. The findings from this study have important implications for the use of the GI concept worldwide and support the application of international values to different ethnic groups. The higher glycaemic response to all foods in Asian Indians may represent another mechanism for increased diabetes susceptibility among Asian Indians.

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Effects of marked hyperthermia with and without dehydration onV˙o 2 kinetics during intense exercise

Journal of Applied Physiology ◽

10.1152/jappl.2001.90.3.1057 ◽

2001 ◽

Vol 90 (3) ◽

pp. 1057-1064 ◽

Cited By ~ 94

Author(s):

Lars Nybo ◽

Thorbjørn Jensen ◽

Bodil Nielsen ◽

José González-Alonso

Keyword(s):

Response Time ◽

Thermal Strain ◽

Cycle Ergometer ◽

Maximal Heart Rate ◽

Exercise Tests ◽

Mean Response Time ◽

Performance Time ◽

Ergometer Exercise ◽

And Performance ◽

Internal Body

This study determined whether marked hyperthermia alone or in combination with dehydration reduces the initial rate of rise in O2 consumption (V˙o 2on-kinetics) and the maximal rate of O2 uptake (V˙o 2 max) during intense cycling exercise. Six endurance-trained male cyclists completed four maximal cycle ergometer exercise tests (402 ± 4 W) when euhydrated or dehydrated (4% body wt) with normal (starting esophageal temperature, 37.5 ± 0.2°C; mean skin temperature, ∼31°C) or elevated (+1 and +6°C, respectively) thermal strain. In the euhydrated and normal condition, subjects reachedV˙o 2 max (4.7 ± 0.2 l/min) in 228 ± 34 s, with a mean response time of 42 ± 2 s, and fatigued after 353 ± 39 s. Hyperthermia alone or in combination with dehydration reduced mean response time (17–23%),V˙o 2 max (16%), and performance time (51–53%) (all P < 0.01) but did not alter the absolute response time (i.e., the time to reach 63% response in the control trial, 3.2 ± 0.1 l/min, 42 s). Reduction inV˙o 2 max was accompanied by proportional decline in O2 pulse and significantly elevated maximal heart rate (195 vs. 190 beats/min for hyperthermia vs. normal). Preventing hyperthermia in dehydrated subjects restoredV˙o 2 max and performance time by 65 and 50%, respectively. These results demonstrate that impaired high-intensity exercise performance with marked skin and internal body hyperthermia alone or in combination with dehydration is not associated with a diminished rate of rise in V˙o 2 but decreased V˙o 2 max.

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Glycaemic response to barley porridge varying in dietary fibre content

British Journal Of Nutrition ◽

10.1017/s0007114511003461 ◽

2011 ◽

Vol 107 (5) ◽

pp. 719-724 ◽

Cited By ~ 12

Author(s):

Pariyarath S. Thondre ◽

Ke Wang ◽

Andrew J. Rosenthal ◽

Christiani J. K. Henry

Keyword(s):

Blood Glucose ◽

Dietary Fibre ◽

Human Subjects ◽

Glycaemic Index ◽

Fibre Content ◽

Postprandial Blood Glucose ◽

Glycaemic Response ◽

Glucose Response ◽

Glucose Levels ◽

Significant Difference

The interest in barley as a food is increasing worldwide because of its high dietary fibre (DF) content and low glycaemic index (GI). DF in cereals may prove beneficial in improving blood glucose response in the long term. However, a dose-dependent effect of insoluble fibre on reducing postprandial blood glucose levels is yet to be proven. The objective of the present study was to determine the glycaemic response to two barley porridges prepared from whole barley grains varying in fibre content. In two separate non-blind randomised crossover trials, ten human subjects consumed barley porridge with 16 g/100 g and 10 g/100 g fibre content provided in different serving sizes (equivalent to 25 and 50 g available carbohydrate). The glycaemic response to both barley porridges was significantly lower than the reference glucose (P < 0·05). There was no significant difference between the glucose areas under the curve or GI for the two barley porridges. We concluded that irrespective of the difference in total fibre content or serving size of barley porridges, their GI values did not differ significantly.

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