scholarly journals Interlimb differences in parameters of aerobic function and local profiles of deoxygenation during double-leg and counterweighted single-leg cycling

2019 ◽  
Vol 317 (6) ◽  
pp. R840-R851 ◽  
Author(s):  
Danilo Iannetta ◽  
Louis Passfield ◽  
Ahmad Qahtani ◽  
Martin J. MacInnis ◽  
Juan M. Murias
Keyword(s):  
Constant Load ◽  
Whole Body ◽  
Aerobic Performance ◽  
Exercise Tests ◽  
Muscle Deoxygenation ◽  
Aerobic Function ◽  
Leg Cycling ◽  
Ramp Exercise ◽  
The Difference ◽  
Leg Dominance

It is typically assumed that in the context of double-leg cycling, dominant (DOMLEG) and nondominant legs (NDOMLEG) have similar aerobic capacity and both contribute equally to the whole body physiological responses. However, there is a paucity of studies that have systematically investigated maximal and submaximal aerobic performance and characterized the profiles of local muscle deoxygenation in relation to leg dominance. Using counterweighted single-leg cycling, this study explored whether peak O2 consumption (V̇o2peak), maximal lactate steady-state (MLSSp), and profiles of local deoxygenation [HHb] would be different in the DOMLEG compared with the NDOMLEG. Twelve participants performed a series of double-leg and counterweighted single-leg DOMLEG and NDOMLEG ramp-exercise tests and 30-min constant-load trials. V̇o2peak was greater in the DOMLEG than in the NDOMLEG (2.87 ± 0.42 vs. 2.70 ± 0.39 L/min, P < 0.05). The difference in V̇o2peak persisted even after accounting for lean mass ( P < 0.05). Similarly, MLSSp was greater in the DOMLEG than in the NDOMLEG (118 ± 31 vs. 109 ± 31 W; P < 0.05). Furthermore, the amplitude of the [HHb] signal during ramp exercise was larger in the DOMLEG than in the NDOMLEG during both double-leg (26.0 ± 8.4 vs. 20.2 ± 8.8 µM, P < 0.05) and counterweighted single-leg cycling (18.5 ± 7.9 vs. 14.9 ± 7.5 µM, P < 0.05). Additionally, the amplitudes of the [HHb] signal were highly to moderately correlated with the mode-specific V̇o2peak values (ranging from 0.91 to 0.54). These findings showed in a group of young men that maximal and submaximal aerobic capacities were greater in the DOMLEG than in the NDOMLEG and that superior peripheral adaptations of the DOMLEG may underpin these differences.

scholarly journals Aerobic Function and Muscle Deoxygenation Dynamics during Ramp Exercise in Children

2015 ◽  
Vol 47 (9) ◽  
pp. 1877-1884 ◽  
Author(s):  
MELITTA A. MCNARRY ◽  
COLIN FARR ◽  
ANDREW MIDDLEBROOKE ◽  
DEBORAH WELFORD ◽  
BRYNMOR BREESE ◽  
...  
Keyword(s):  
Muscle Deoxygenation ◽  
Aerobic Function ◽  
Ramp Exercise

Instantaneous quantification of skeletal muscle activation, power production, and fatigue during cycle ergometry

2015 ◽  
Vol 118 (5) ◽  
pp. 646-654 ◽  
Author(s):  
A. C. Coelho ◽  
D. T. Cannon ◽  
R. Cao ◽  
J. Porszasz ◽  
R. Casaburi ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Muscle Activation ◽  
Linear Velocity ◽  
Analysis Of Covariance ◽  
Whole Body ◽  
Maximal Power ◽  
Limits Of Agreement ◽  
Exercise Tests ◽  
The Difference ◽  
Healthy Participants

A rapid switch from hyperbolic to isokinetic cycling allows the velocity-specific decline in maximal power to be measured, i.e., fatigue. We reasoned that, should the baseline relationship between isokinetic power (Piso) and electromyography (EMG) be reproducible, then contributions to fatigue may be isolated from 1) the decline in muscle activation (muscle activation fatigue); and 2) the decline in Piso at a given activation (muscle fatigue). We hypothesized that the EMG-Piso relationship is linear, velocity dependent, and reliable for instantaneous fatigue assessment at intolerance during and following whole body exercise. Healthy participants ( n = 13) completed short (5 s) variable-effort isokinetic bouts at 50, 70, and 100 rpm to characterize baseline EMG-Piso. Repeated ramp incremental exercise tests were terminated with maximal isokinetic cycling (5 s) at 70 rpm. Individual baseline EMG-Piso relationships were linear ( r2 = 0.95 ± 0.04) and velocity dependent (analysis of covariance). Piso at intolerance (two legs, 335 ± 88 W) was ∼45% less than baseline [630 ± 156 W, confidence interval of the difference (CIDifference) 211, 380 W, P < 0.05]. Following intolerance, Piso recovered rapidly ( F = 44.1; P < 0.05; η2 = 0.79): power was reduced ( P < 0.05) vs. baseline only at 0-min (CIDifference 80, 201 W) and 1-min recovery (CIDifference 13, 80 W). Activation fatigue and muscle fatigue (one leg) were 97 ± 55 and 60 ± 50 W, respectively. Mean bias ± limits of agreement for reproducibility were as follows: baseline Piso 1 ± 30 W; Piso at 0-min recovery 3 ± 35 W; and EMG at Piso 3 ± 14%. EMG power is linear, velocity dependent, and reproducible. Deviation from this relationship at the limit of tolerance can quantify the “activation” and “muscle” related components of fatigue during cycling.

Kinematic contribution and synchronization of the trunk, hip, and knee during free-dynamic lifting

2003 ◽  
Vol 3 (2) ◽  
pp. 99-108
Author(s):  
Kermit G. Davis ◽  
Riley E. Splittstoesser ◽  
William S. Marras
Keyword(s):  
Whole Body ◽  
Knee Height ◽  
Squat Lifting ◽  
The Difference ◽  
Free Dynamic ◽  
Body Lifting ◽  
And Task ◽  
Kinematic Contribution ◽  
Stoop Lifting

Although there have been numerous studies evaluating the difference between stooped and squat lifting styles, there remains a lack of understanding of whole body kinematics during unrestricted lifting. The current study evaluated nine males and nine females while lifting two box weights (9.1 kg, 18.2 kg) from five origins below the waist (0, 19, 38, 57, and 76 cm above the floor) and from three task asymmetries (sagittally symmetric, 45° clockwise, 45° counter-clockwise). While the lifting style was significantly influenced by the height of lift origin and to a lesser extent gender, box weight, and task asymmetry, none of the conditions resulted in pure squat or stoop lifting style. However, for lifts above knee height, the lifting style resembled more of a stoop lift while lifts originating below knee height were more of a squat lift. As the origin moved closer to the floor, participants relied more on their hips to accomplish the sagittal flexion but overall adopted a more coordinated whole-body lifting style. All together, as more sagittal flexion is required, more joints are relied upon in a more coordinated effort. The current study indicates that caution needs to be exercised when applying results of pure squat or pure stoop lifting studies to free-style (realistic) lifting.

Longitudinal changes in the kinetic response to heavy-intensity exercise in children

2004 ◽  
Vol 97 (2) ◽  
pp. 460-466 ◽  
Author(s):  
Samantha G. Fawkner ◽  
Neil Armstrong
Keyword(s):  
Slow Component ◽  
Phase 1 ◽  
Exponential Model ◽  
Cycle Ergometer ◽  
Primary Component ◽  
Total Change ◽  
Exercise Tests ◽  
Longitudinal Changes ◽  
Dependent Change ◽  
The Difference

The purpose of this study was to investigate longitudinal changes with age in the kinetic response to cycling at heavy-intensity exercise in boys and girls. Twenty-two prepubertal children (13 male, 9 female) carried out a series of exercise tests on two test occasions with a 2-yr interval. On each test occasion, the subject completed multiple transitions from baseline to 40% of the difference between their previously determined V-slope and peak O2 uptake (V̇o2) for 9 min on an electronically braked cycle ergometer. Each subject's breath-by-breath responses were interpolated to 1-s intervals, time aligned, and averaged. The data after phase 1 were fit with 1) a double exponential model and 2) a single exponential model within a fitting window that was previously identified to exclude the slow component. There were no significant differences in the parameters of the primary component between each model. Subsequent analysis was carried out using model 2. The V̇o2 slow component was computed as the difference between the amplitude of the primary component and the end-exercise V̇o2 and was expressed as the percent contribution to the total change in V̇o2. Over the 2-yr period, the primary time constant (boys 16.8 ± 5.3 and 21.7 ± 5.3 s, girls 21.1 ± 8.1 and 26.4 ± 8.4 s, first and second occasion, respectively) and the relative amplitude of the slow component (boys 9.4 ± 4.6 and 13.8 ± 5.3%, girls 10.3 ± 2.4 and 15.5 ± 2.8%, first and second occasion, respectively) significantly increased with no sex differences. The data demonstrate that children do display a slow-component response to exercise and are consistent with an age-dependent change in the muscles' potential for O2 utilization.

Rate of loss of radioiron from mouse and man

1960 ◽  
Vol 198 (4) ◽  
pp. 784-786 ◽  
Author(s):  
John D. Bonnet ◽  
Alan L. Orvis ◽  
Albert B. Hagedorn ◽  
Charles A. Owen
Keyword(s):  
Life Span ◽  
Half Life ◽  
Whole Body ◽  
Entire Body ◽  
Rapid Loss ◽  
Male And Female ◽  
Female Mice ◽  
Steady Rate ◽  
Normal Man ◽  
The Difference

Forty-two male and female mice, 8 weeks old, were given radioiron (Fe59) in doses of 0.006–0.1 µc, containing 0.013–0.17 µg of iron, by intraperitoneal or intravenous routes. Assays of the radioactivity of the whole body revealed an initial rapid loss of Fe59 (15–20%) lasting about 6 days. Thereafter the Fe59 left the mice at a steady rate of 0.39%/day (half-life 180 days). One 34-year-old normal man was given 10.6 µc of Fe59, containing 8.2 µg of iron, intravenously. Based on counts from the entire body, the biologic rate of loss of the Fe59 was about 0.14%/day (half-life 500 days), and there was little or no initial loss such as occurred in the mouse. The Fe59 in the circulating erythrocytes was essentially unchanged for the first 3 months. It then fell to a new level of about 90% of the previous one; the mid-point of the fall was about 120 days after the administration of the radioiron. The difference in the rates of loss of radioiron from mice and man seems to be related primarily to the life span of the circulating red cells.

Influence of endurance training on muscle [PCr] kinetics during high-intensity exercise

2007 ◽  
Vol 293 (1) ◽  
pp. R392-R401 ◽  
Author(s):  
Andrew M. Jones ◽  
Daryl P. Wilkerson ◽  
Nicolas J. Berger ◽  
Jonathan Fulford
Keyword(s):  
Endurance Training ◽  
High Intensity ◽  
Slow Component ◽  
Knee Extension ◽  
High Intensity Exercise ◽  
Whole Body ◽  
Time To Exhaustion ◽  
Exercise Tests ◽  
Before And After ◽  
Knee Extension Exercise

We hypothesized that a period of endurance training would result in a speeding of muscle phosphocreatine concentration ([PCr]) kinetics over the fundamental phase of the response and a reduction in the amplitude of the [PCr] slow component during high-intensity exercise. Six male subjects (age 26 ± 5 yr) completed 5 wk of single-legged knee-extension exercise training with the alternate leg serving as a control. Before and after the intervention period, the subjects completed incremental and high-intensity step exercise tests of 6-min duration with both legs separately inside the bore of a whole-body magnetic resonance spectrometer. The time-to-exhaustion during incremental exercise was not changed in the control leg [preintervention group (PRE): 19.4 ± 2.3 min vs. postintervention group (POST): 19.4 ± 1.9 min] but was significantly increased in the trained leg (PRE: 19.6 ± 1.6 min vs. POST: 22.0 ± 2.2 min; P < 0.05). During step exercise, there were no significant changes in the control leg, but end-exercise pH and [PCr] were higher after vs. before training. The time constant for the [PCr] kinetics over the fundamental exponential region of the response was not significantly altered in either the control leg (PRE: 40 ± 13 s vs. POST: 43 ± 10 s) or the trained leg (PRE: 38 ± 8 s vs. POST: 40 ± 12 s). However, the amplitude of the [PCr] slow component was significantly reduced in the trained leg (PRE: 15 ± 7 vs. POST: 7 ± 7% change in [PCr]; P < 0.05) with there being no change in the control leg (PRE: 13 ± 8 vs. POST: 12 ± 10% change in [PCr]). The attenuation of the [PCr] slow component might be mechanistically linked with enhanced exercise tolerance following endurance training.

scholarly journals HUMAN BODY’S HEALTH FUNCTION IMPROVEMENT BY VARIOUS WHOLE-BODY SPORTS EXERCISES

2021 ◽  
Vol 27 (3) ◽  
pp. 270-273
Author(s):  
Ji Hu ◽  
Jicheng Yang
Keyword(s):  
Physical Exercise ◽  
Human Health ◽  
Tai Chi ◽  
Exercise Group ◽  
Whole Body ◽  
Group Health ◽  
Traditional Health ◽  
Physical Exercises ◽  
The Difference ◽  
Health Function

ABSTRACT Introduction Studies have shown that physical exercise is beneficial to people’s overall physical and mental health, but few research reports on the effects of different physical exercises on people’s human health. Object The paper explores the difference in human health function between people who adhere to traditional health sports and those who rarely exercise and provide a scientific basis for applying and promoting traditional health sports in TCM “prevention of disease”. Methods The paper surveyed 526 people who regularly participate in physical exercises and rarely exercise. The exercise items are divided into Tai Chi/Tai Chi sword group, Health Qigong Baduanjin group, Health Qigong Wuqinxi group, and Health Qigong Yijin group. Warp group, walking/jogging group. Results There are differences in the mental indicators of the people in different exercise groups. The overall average percentage levels of and NK cells in each exercise group and the tiny exercise group are different, and the difference is statistically significant (P<0.05). Conclusions Persisting in physical exercise is beneficial to the balance of health and function of the population. Level of evidence II; Therapeutic studies - investigation of treatment results.

scholarly journals Hematopoietic Recovery after Transplantation CD117+B220- (lacZ+) Bone Marrow Cells in Lethally Irradiated Mice

2008 ◽  
Vol 51 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Miroslav Hodek ◽  
Jiřina Vávrová ◽  
Zuzana Šinkorová ◽  
Jaroslav Mokrý ◽  
Stanislav Filip
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Repair Process ◽  
Whole Body ◽  
Lacz Gene ◽  
Colony Forming Units ◽  
The Difference ◽  
Macrophage Colony ◽  
Marrow Cells

Experiments presented here were aimed at the description of hematopoiesis repair and in vivo homing of transplanted separated CD117+B220–bone marrow cells after whole-body lethal irradiation at LD 9Gy. ROSA 26 mice were used as donors of marrow cells for transplantation [B6;129S/Gt (ROSA)26Sor] and were tagged with lacZ gene, and F2 hybrid mice [B6129SF2/J] were used as recipients of bone marrow transplanted cells. Hematopoiesis repair was provided by transplantation, both suspension of whole bone marrow cells (5x106) and isolated CD117+B220–cells (5x104). Mice survived up to thirty days after irradiation. We demonstrated that transplantation of suspension of whole bone marrow cells led to faster recovery of CFU-GM (Granulocyte-macrophage colony forming units) in bone marrow and in the spleen too. It is not clear what the share of residential and transplanted cells is in the repair process. Our results demonstrate that sufficient hematopoietic repair occurs after transplantation of CD117+B220–(lacZ+) in lethally irradiated mice, and the difference in CFU-GM numbers in the bone marrow and spleen found on day 8 posttransplant has no influence on the survival of lethally irradiated mice (30 days follow-up).

scholarly journals Effects of isoenergetic overfeeding of either carbohydrate or fat in young men

2000 ◽  
Vol 84 (2) ◽  
pp. 233-245 ◽  
Author(s):  
Ole Lammert ◽  
Niels Grunnet ◽  
Peter Faber ◽  
Kirsten Schroll Bjørnsbo ◽  
John Dich ◽  
...  
Keyword(s):  
Fat Mass ◽  
De Novo ◽  
Fat Free Mass ◽  
Whole Body ◽  
Distribution Analysis ◽  
Mass Isotopomer Distribution Analysis ◽  
The Difference ◽  
Normal Men ◽  
Plasma Leptin ◽  
Mass Increase

Ten pairs of normal men were overfed by 5 MJ/d for 21 d with either a carbohydrate-rich or a fat-rich diet (C- and F-group). The two subjects in each pair were requested to follow each other throughout the day to ensure similar physical activity and were otherwise allowed to maintain normal daily life. The increase in body weight, fat free mass and fat mass showed great variation, the mean increases being 1·5 kg, 0·6 kg and 0·9 kg respectively. No significant differences between the C- and F-group were observed. Heat production during sleep did not change during overfeeding. The RQ during sleep was 0·86 and 0·78 in the C- and F-group respectively. The accumulated faecal loss of energy, DM, carbohydrate and protein was significantly higher in the C- compared with the F-group (30, 44, 69 and 51 % higher respectively), whereas the fat loss was the same in the two groups. N balance was not different between the C- and F-group and was positive. Fractional contribution from hepatic de novo lipogenesis, as measured by mass isotopomer distribution analysis after administration of [1-13C]acetate, was 0·20 and 0·03 in the C-group and the F-group respectively. Absolute hepatic de novo lipogenesis in the C-group was on average 211 g per 21 d. Whole-body de novo lipogenesis, as obtained by the difference between fat mass increase and dietary fat available for storage, was positive in six of the ten subjects in the C-group (mean 332 (SEM 191) g per 21 d). The change in plasma leptin concentration was positively correlated with the change in fat mass. Thus, fat storage during overfeeding of isoenergetic amounts of diets rich in carbohydrate or in fat was not significantly different, and carbohydrates seemed to be converted to fat by both hepatic and extrahepatic lipogenesis.

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