Effect of Endurance Training on Different Mechanical Efficiency Indices During Submaximal Cycling in Subjects Unaccustomed to Cycling

2005 ◽  
Vol 30 (5) ◽  
pp. 520-528 ◽  
Author(s):  
Frédérique Hintzy ◽  
Laurent Mourot ◽  
Stéphane Perrey ◽  
Nicolas Tordi
Keyword(s):  
Endurance Training ◽  
Mechanical Efficiency ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometer ◽  
Baseline Correction ◽  
Baseline Subtraction ◽  
Work Cycle ◽  
Before And After ◽  
Resting Metabolism ◽  
Sedentary Women

The purpose of this study was to evaluate different efficiency indices, i.e., gross (GE: no baseline correction), net (NE: resting metabolism as baseline correction), and work (WE: unloaded exercise as baseline correction), to reveal the effect of endurance training on mechanical efficiency. Nine healthy sedentary women undertook an incremental test and submaximal cycling exercise, at an intensity corresponding to 50% of the pretraining peak oxygen uptake, before and after 6 weeks of endurance training (18 sessions of 45 min). The training effects on efficiency indices were tested by comparisons based on GE, NE, and WE as well as by the differences between the percentage changes of all indices (% GE, % NE, % WE). Endurance training resulted in significantly higher GE (+ 11.1%; p <  0.001) and NE (+ 9.1%; P <  0.01). Only minor significant improvement (+ 2.4%; p <  0.05) was observed with the WE index because the value used for baseline subtraction was significantly reduced by the training sessions, due perhaps to improvement in pedaling skill. As a consequence, % WE was significantly lower than % GE (p <  0.01) and % NE (p <  0.05), while % GE and % NE were not significantly different. We conclude that mechanical efficiency of cycling increases with training in women previously unfamiliar with cycling, and that the WE index is less sensitive to this training effect than GE and NE indices. Key words: gross efficiency, net efficiency, work efficiency, internal work, cycle ergometer

Ten-day endurance training attenuates the hyperosmotic suppression of cutaneous vasodilation during exercise but not sweating

2005 ◽  
Vol 99 (1) ◽  
pp. 237-243 ◽  
Author(s):  
Takashi Ichinose ◽  
Kazunobu Okazaki ◽  
Shizue Masuki ◽  
Hiroyuki Mitono ◽  
Mian Chen ◽  
...  
Keyword(s):  
Endurance Training ◽  
Exercise Intensity ◽  
Plasma Osmolality ◽  
Young Male ◽  
Cycle Ergometer ◽  
Peak Oxygen Consumption ◽  
Cutaneous Vasodilation ◽  
Thermoregulatory Responses ◽  
Before And After ◽  
The Individual

It is well known that hyperosmolality suppresses thermoregulatory responses and that plasma osmolality (Posmol) increases with exercise intensity. We examined whether the decreased esophageal temperature thresholds for cutaneous vasodilation (THFVC) and sweating (THSR) after 10-day endurance training (ET) are caused by either attenuated increase in Posmol at a given exercise intensity or blunted sensitivity of hyperosmotic suppression. Nine young male volunteers exercised on a cycle ergometer at 60% peak oxygen consumption rate (V̇o2 peak) for 1 h/day for 10 days at 30°C. Before and after ET, thermoregulatory responses were measured during 20-min exercise at pretraining 70% V̇o2 peak in the same environment as during ET under isoosmotic or hyperosmotic conditions. Hyperosmolality by ∼10 mosmol/kgH2O was attained by acute hypertonic saline infusion. After ET, V̇o2 peak and blood volume (BV) both increased by ∼4% ( P < 0.05), followed by a decrease in THFVC ( P < 0.05) but not by that in THSR. Although there was no significant decrease in Posmol at the thresholds after ET, the sensitivity of increase in THFVC at a given increase in Posmol [ΔTHFVC/ΔPosmol,°C·(mosmol/kgH2O)−1], determined by hypertonic infusion, was reduced to 0.021 ± 0.005 from 0.039 ± 0.004 before ET ( P < 0.05). The individual reductions in ΔTHFVC/ΔPosmol after ET were highly correlated with their increases in BV around THFVC ( r = −0.89, P < 0.005). In contrast, there was no alteration in the sensitivity of the hyperosmotic suppression of sweating after ET. Thus the downward shift of THFVC after ET was partially explained by the blunted sensitivity to hyperosmolality, which occurred in proportion to the increase in BV.

Anaerobic threshold alterations caused by endurance training in middle-aged men

1979 ◽  
Vol 46 (6) ◽  
pp. 1039-1046 ◽  
Author(s):  
J. A. Davis ◽  
M. H. Frank ◽  
B. J. Whipp ◽  
K. Wasserman
Keyword(s):  
Endurance Training ◽  
Anaerobic Threshold ◽  
Minute Ventilation ◽  
Correlation Coefficients ◽  
Cycle Ergometer ◽  
Work Rate ◽  
Middle Aged ◽  
Co2 Output ◽  
Before And After ◽  
Cycle Endurance

Nine previously sedentary middle-aged males underwent cycle endurance training 45 min/day for 9 wk with an average attendance of 4.1 days/wk. Seven males served as controls. Before and after the training period, the subjects performed three cycle ergometer tests. Work rate was incremented by 15 W/min, to the limit of the subjects' tolerance, in the first two tests; the third test consisted of contant-load cycling at an O2 uptake (VO2) just below the pretraining anaerobic threshold (AT). After training, the AT increased significantly by 44%, expressed as absolute VO2, and by 15%, expressed relative to VO2 max. Significant increases were also noted in VO2max (25%), maximal minute ventilation (19%), and maximal work rate (28%). The test-retest correlation coefficients for the AT (%VO2max) were 0.91, pre- and posttraining. Training did not alter steady-state VO2 during the submaximal exercise test whereas significant decreases occurred in CO2 output, VE, respiratory quotient, and VE/VO2. No changes occurred in the control subjects during this period. These results demonstrate that the AT is profoundly influenced by endurance training in previously sedentary middle-aged males.

scholarly journals Effect of Combined Endurance Training and MitoQ on Cardiac Function and Serum Level of Antioxidants, NO, miR-126, and miR-27a in Hypertensive Individuals

2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Yaser Masoumi-Ardakani ◽  
Hamid Najafipour ◽  
Hamid Reza Nasri ◽  
Soheil Aminizadeh ◽  
Shirin Jafari ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Endurance Training ◽  
Cardiovascular Health ◽  
Serum Levels ◽  
Cycle Ergometer ◽  
Moderate Intensity ◽  
Double Blind ◽  
Treatment Groups ◽  
Before And After ◽  
And Control

Objectives. Hypertension (HTN) is one of the most important risk factors for cardiovascular diseases. Despite advances in treatment and control of HTN, the prevalence of HTN is still increasing. MitoQ is a supplement that acts on mitochondria and attenuates reactive oxygen species (ROS), which plays an important role in cardiovascular health. miRNAs play an important role in the pathophysiology of HTN. We evaluated the effects of MitoQ supplementation and endurance training (ET), alone and in combination, on functional indices of the heart and serum levels of miR-126, miR-27a, antioxidants, and NO, in patients with HTN. Methods. In a double-blind randomized clinical trial, 52 male participants (age 40-55 years) were randomly divided into four groups ( n = 13 ) of placebo, MitoQ (20 mg/day, oral), ET (cycle ergometer, moderate intensity, 40-60% VO2 peak, heart rate 120-140 b/min, 45 min a day, three days/week for six weeks), and MitoQ+ET. Cardiac function indices were assessed by echocardiography before and after interventions. Results. Systolic blood pressure (SBP) significantly decreased in all intervention groups ( P < 0.001 ) while DBP ( P < 0.01 ) and LV hypertrophy ( P < 0.05 ) were significantly decreased only in the MitoQ+ET group. Serum levels of SOD, GPx, and NO and the level of miR-126 significantly increased in all treatment groups, while miR-27a reduced in the ET ( P < 0.05 ) and MitoQ+ET ( P < 0.01 ) groups. Conclusions. Compared to MitoQ and ET alone, their combination has more prominent improving effects on cardiac health and amelioration of BP in the patients with HTN. These effects are through miR-126 and miR-27a modulation and ameliorating mitochondrial ROS production.

Comparison of performing 12 weeks’ resistance training before, after and/or in between aerobic exercise on the hormonal status of aged women: a randomized controlled trial

2018 ◽  
Vol 35 (3) ◽  
Author(s):  
Ebrahim Banitalebi ◽  
Mohammad Faramarzi ◽  
Laleh Bagheri ◽  
Abdol Reza Kazemi
Keyword(s):  
Resistance Training ◽  
Aerobic Exercise ◽  
Endurance Training ◽  
Controlled Trial ◽  
Cycle Ergometer ◽  
Endocrine Function ◽  
Control Group ◽  
Hormonal Status ◽  
Combined Training ◽  
Before And After

Abstract Background Physiological aging can now be considered as a multi-factorial process that is associated with anatomical and signaling changes associated with endocrine function. The purpose of this study was to investigate the comparison of performing 12 weeks’ resistance training before, after and/or in between aerobic exercise on the hormonal status of aged women. Materials and methods Forty healthy aged women (age: 67.35 ± 1.40 years) were randomly divided into three training groups and a control group: resistance followed by endurance training (ER, n = 12), endurance training followed by resistance training (RE, n = 12, interval resistance-endurance (RE) training (INT, n = 12) and a control (Con, n = 12) groups. The training program was done over 12 weeks, 3 times per week. Endurance training was performed on a cycle ergometer (intensity: 60–90% maximum heart rate) and resistance training involved selected resistance exercises (intensity: 40–75 one-repetition maximum, 8–18 repeats). All participants were evaluated before and after the training period. Results and conclusion The data showed that performing resistance training before, after and/or in between aerobic exercise did not influence the adaptive response of insulin like growth factor-1 (IGF-1) (p = 0.07), growth hormone (p = 0.35), cortisol (p = 0.20), insulin (p = 0.72), epinephrine (p = 0.83) and norepinephrine (p = 0.86) levels throughout the study. However, when comparing pre and post, no significant differences were shown following combined training within the SE, ES and INT groups for all variables (p < 0.05), except of IGF-1 within ES (p = 0.04) and SE (p = 0.02), and testosterone within ES (p = 0.007). In conclusion, combined training with RE order may be more effective than other orders for increasing anabolic status in aged women.

Endurance training decreases plasma glucose turnover and oxidation during moderate-intensity exercise in men

1990 ◽  
Vol 68 (3) ◽  
pp. 990-996 ◽  
Author(s):  
A. R. Coggan ◽  
W. M. Kohrt ◽  
R. J. Spina ◽  
D. M. Bier ◽  
J. O. Holloszy
Keyword(s):  
Endurance Training ◽  
Plasma Glucose ◽  
Cycle Ergometer ◽  
Fat Free Mass ◽  
Strenuous Exercise ◽  
Moderate Intensity ◽  
Glucose Turnover ◽  
Moderate Intensity Exercise ◽  
Ergometer Exercise ◽  
Before And After

To assess the effects of endurance training on plasma glucose kinetics during moderate-intensity exercise in men, seven men were studied before and after 12 wk of strenuous exercise training (3 days/wk running, 3 days/wk cycling). After priming of the glucose and bicarbonate pools, [U-13C] glucose was infused continuously during 2 h of cycle ergometer exercise at 60% of pretraining peak O2 uptake (VO2) to determine glucose turnover and oxidation. Training increased cycle ergometer peak VO2 by 23% and decreased the respiratory exchange ratio during the final 30 min of exercise from 0.89 +/- 0.01 to 0.85 +/- 0.01 (SE) (P less than 0.001). Plasma glucose turnover during exercise decreased from 44.6 +/- 3.5 mumol.kg fat-free mass (FFM)-1.min-1 before training to 31.5 +/- 4.3 after training (P less than 0.001), whereas plasma glucose clearance (i.e., rate of disappearance/plasma glucose concentration) fell from 9.5 +/- 0.6 to 6.4 +/- 0.8 ml.kg FFM-1.min-1 (P less than 0.001). Oxidation of plasma-derived glucose, which accounted for approximately 90% of plasma glucose disappearance in both the untrained and trained states, decreased from 41.1 +/- 3.4 mumol.kg FFM-1.min-1 before training to 27.7 +/- 4.8 after training (P less than 0.001). This decrease could account for roughly one-half of the total reduction in the amount of carbohydrate utilized during the final 30 min of exercise in the trained compared with the untrained state.

Isotopic estimation of CO2 production during exercise before and after endurance training

1993 ◽  
Vol 75 (1) ◽  
pp. 70-75 ◽  
Author(s):  
A. R. Coggan ◽  
D. L. Habash ◽  
L. A. Mendenhall ◽  
S. C. Swanson ◽  
C. L. Kien
Keyword(s):  
Endurance Training ◽  
Tricarboxylic Acid Cycle ◽  
Cycle Ergometer ◽  
Submaximal Exercise ◽  
Carbohydrate Oxidation ◽  
Whole Body ◽  
Co2 Production ◽  
Acid Oxidation ◽  
Ergometer Exercise ◽  
Before And After

Endurance training reduces the rate of CO2 release (i.e., VCO2) during submaximal exercise, which has been interpreted to indicate a reduction in carbohydrate oxidation. However, decreased ventilation, decreased buffering of lactate, and/or increased fixation of CO2 could also account for a lower VCO2 after training. We therefore used a primed continuous infusion of NaH13CO3 to determine the whole body rate of appearance of CO2 (RaCO2) in seven men during 2 h of cycle ergometer exercise at 60% of pretraining peak O2 uptake (VO2peak) before and after endurance training. RaCO2 is independent of the above-described factors affecting VCO2 but may overestimate net CO2 production due to pyruvate carboxylation and subsequent isotopic exchange in the tricarboxylic acid cycle. Training consisted of cycling at 75–100% VO2peak for 45–90 min/day, 6 days/wk, for 12 wk and increased VO2peak by 28% (P < 0.001). VCO2 during submaximal exercise was reduced from 86.8 +/- 3.7 to 76.2 +/- 4.2 mmol/min, whereas RaCO2 fell from 88.9 +/- 4.0 to 76.4 +/- 4.4 mmol/min (both P < 0.001). VCO2 and RaCO2 were highly correlated in the untrained (r = 0.98, P < 0.001) and trained (r = 0.99, P < 0.001) states, as were individual changes in VCO2 and RaCO2 with training (r = 0.88, P < 0.01). These results support the hypothesis that endurance training decreases CO2 production during exercise. The magnitude and direction of this change cannot be explained by reported training-induced alterations in amino acid oxidation, indicating that it must be the result of a decrease in carbohydrate oxidation and an increase in fat oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Ten days of exercise training reduces glucose production and utilization during moderate-intensity exercise

1994 ◽  
Vol 266 (1) ◽  
pp. E136-E143 ◽  
Author(s):  
L. A. Mendenhall ◽  
S. C. Swanson ◽  
D. L. Habash ◽  
A. R. Coggan
Keyword(s):  
Endurance Training ◽  
Time Course ◽  
Plasma Concentrations ◽  
Glucose Production ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometer ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Ergometer Exercise ◽  
Exercise Induced

We have previously shown that 12 wk of endurance training reduces the rate of glucose appearance (Ra) during submaximal exercise (Coggan, A. R., W. M. Kohrt, R. J. Spina, D. M. Bier, and J. O. Holloszy. J. Appl. Physiol. 68: 990-996, 1990). The purpose of the present study was to examine the time course of and relationship between training-induced alterations in glucose kinetics and endocrine responses during prolonged exercise. Accordingly, seven men were studied during 2 h of cycle ergometer exercise at approximately 60% of pretraining peak oxygen uptake on three occasions: before, after 10 days, and after 12 wk of endurance training. Ra was determined using a primed, continuous infusion of [6,6-2H]glucose. Ten days of training reduced mean Ra during exercise from 36.9 +/- 3.3 (SE) to 28.5 +/- 3.4 mumol.min-1.kg-1 (P < 0.001). Exercise-induced changes in insulin, C-peptide, glucagon, norepinephrine, and epinephrine were also significantly blunted. After 12 wk of training, Ra during exercise was further reduced to 21.5 +/- 3.1 mumol.min-1.kg-1 (P < 0.001 vs. 10 days), but hormone concentrations were not significantly different from 10-day values. The lower glucose Ra during exercise after short-term (10 days) training is accompanied by, and may be due to, altered plasma concentrations of the major glucoregulatory hormones. However, other adaptations must be responsible for the further reduction in Ra with more prolonged training.

Effect of prolonged exercise on muscle citrate concentration before and after endurance training in men

1993 ◽  
Vol 264 (2) ◽  
pp. E215-E220 ◽  
Author(s):  
A. R. Coggan ◽  
R. J. Spina ◽  
W. M. Kohrt ◽  
J. O. Holloszy
Keyword(s):  
Endurance Training ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Cycle Ergometer ◽  
Vastus Lateralis Muscle ◽  
Carbohydrate Utilization ◽  
Citrate Concentration ◽  
P Concentration ◽  
Ergometer Exercise ◽  
Before And After

It has been hypothesized that endurance training reduces carbohydrate utilization during exercise via citrate-mediated inhibition of phosphofructokinase (PFK). To test this hypothesis, vastus lateralis muscle biopsy samples were obtained from eight men before and immediately (approximately 10 s) after 2 h of cycle ergometer exercise at 60% of pretraining peak O2 uptake, both before and after 12 wk of endurance exercise training (3 days/wk running, 3 days/wk interval cycling). Training increased muscle citrate synthase (CS) activity from 3.69 +/- 0.48 (SE) to 5.30 +/- 0.42 mol.h-1.kg protein-1 and decreased the mean respiratory exchange ratio during exercise from 0.92 +/- 0.01 to 0.88 +/- 0.01 (both P < 0.001). Muscle citrate concentration at the end of exercise correlated significantly with CS activity (r = 0.70; P < 0.005) and was slightly but not significantly higher after training (0.80 +/- 0.19 vs. 0.54 +/- 0.19 mmol/kg dry wt; P = 0.16). Muscle glucose 6-phosphate (G-6-P) concentration at the end of exercise, however, was 31% lower in the trained state (1.17 +/- 0.10 vs. 1.66 +/- 0.27 mmol/kg dry wt; P < 0.05), in keeping with a 36% decrease in the amount of muscle glycogen utilized (133 +/- 22 vs. 209 +/- 19 mmol.kg dry wt-1.2 h-1; P < 0.01). The lower G-6-P concentration after training suggests that the training-induced reduction in carbohydrate utilization results from attenuation of flux before the PFK step in glycolysis and is not due to citrate-mediated inhibition of PFK.

scholarly journals Peak Oxygen Uptake and Muscle Power Can Be Simultaneously Improved with Hybrid Training

2015 ◽  
Vol 6 (2) ◽  
pp. 1-13
Author(s):  
Johnny Nilsson ◽  
Mårten Fredriksson
Keyword(s):  
Oxygen Uptake ◽  
Muscle Power ◽  
Intervention Group ◽  
Training Group ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometer ◽  
Power Performance ◽  
Continuous Training ◽  
Training Time ◽  
Before And After

Abstract The purpose was to investigate the effects of simultaneous endurance and strength training repeatedly performed in the same training sessions (hybrid training). Twenty-six habitually active female physical-education students took part in the study. They were assigned to a hybrid training group (HT) or one of two control groups (CON1; only endurance training and CON2; maintained their normal training regimen). In a pre- and post-test training design all the subjects were tested before and after the intervention period concerning peak oxygen uptake while pedalling on a cycle ergometer and power output in a progressive cycle ergometer pedalling power/strength test. The HT intervention group and the CON1 group trained three times per week for five weeks, while the CON2 group did not change their normal training regimen. The HT group used a pre-programmed cycle ergometer to pedal at a mean oxygen uptake of 70-75% VO2peak for 30 minutes, but the training time was divided into 60 intermittent work periods (6 seconds) at a very high relative intensity (approximately 190 % of VO2peak) interspersed with low-intensity work periods (24 seconds) at about 45% of VO2peak. The CON1 group trained at the same mean oxygen uptake level as the HT group but during 30 minutes continuous training. The HT group significantly increased VO2peak and muscle power performance. The CON1 group increased VO2peak significantly but not power/strength. The CON2 group did not change significantly in the parameters studied. Thus, it can be concluded that in-session hybrid training allows simultaneous significant improvements of both VO2peak and muscle power performance during cycle ergometer pedalling.

Substrate utilization during endurance exercise in men and women after endurance training

2001 ◽  
Vol 280 (6) ◽  
pp. E898-E907 ◽  
Author(s):  
S. L. Carter ◽  
C. Rennie ◽  
M. A. Tarnopolsky
Keyword(s):  
Endurance Training ◽  
Endurance Exercise ◽  
Cycle Ergometer ◽  
Whole Body ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Glucose Flux ◽  
Before And After ◽  
Glycerol Utilization ◽  
Males And Females

We investigated the effect of endurance training on whole body substrate, glucose, and glycerol utilization during 90 min of exercise at 60% peak O2 consumption (V˙o 2 peak) in males and females. Substrate oxidation was determined before and after 7 wk of endurance training on a cycle ergometer, with posttesting performed at the same absolute (ABS, W) and relative (REL, %V˙o 2 peak) intensities. [6,6-2H]glucose and [1,1,2,3,3-2H]glycerol tracers were used to calculate the respective substrate tracee flux. Endurance training resulted in an increase inV˙o 2 peak for both males and females of 17 and 22%, respectively ( P < 0.001). Females demonstrated a lower respiratory exchange ratio (RER) both pretraining and posttraining compared with males during exercise ( P< 0.001). Glucose rate of appearance (Ra) and rate of disappearance (Rd) were not different between males and females. Glucose metabolic clearance rate (MCR) was lower at 75 and 90 min of exercise for females compared with males ( P < 0.05). Glucose Ra and Rd were lower during exercise at both ABS and REL posttraining exercise intensities compared with pretraining ( P < 0.001). Females had a higher exercise glycerol Ra and Rd compared with males both pre- and posttraining ( P < 0.001). Glycerol Ra was not different at either the ABS or REL posttraining exercise intensities compared with pretraining. We concluded that females oxidize proportionately more lipid and less carbohydrate during exercise compared with males both pre- and posttraining, which was cotemporal with a higher glycerol Ra in females. Furthermore, endurance training resulted in a decrease in glucose flux at both ABS and REL exercise intensities after endurance exercise training.

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