Sex Differences in Running Economy of Young Children

1999 ◽  
Vol 11 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Don W. Morgan ◽  
Wayland Tseh ◽  
Jennifer L. Caputo ◽  
Ian S. Craig ◽  
Daniel J. Keefer ◽  
...  
Keyword(s):  
Sex Differences ◽  
Oxygen Uptake ◽  
Body Fat ◽  
Running Economy ◽  
Fat Free Mass ◽  
Treadmill Running ◽  
Fat Percentage ◽  
Total Body Mass ◽  
Energy Demands ◽  
Total Body

The purpose of this study was to quantify running economy (RE) during level treadmill running in 6-year-old children and to identify the potentially mediating effects of resting oxygen uptake and body fat percentage on sex differences in RE. Resting oxygen uptake (VO2), body fat, and RE at 5 mph were quantified in 15 boys and 20 girls following 30 min of treadmill accommodation. While absolute VO2 and mass-related values of gross and net VO2 were significantly higher in boys compared to girls, gross VO2 expressed relative to fat-free mass was not different between sexes. These results indicate that 6-year-old girls exhibit better RE compared to 6-year-old boys when VO2 is expressed as a function of total body mass. This sex difference in VO2 may reflect an increase in aerobic energy demands associated with the presence of a greater muscle mass in boys.

scholarly journals Hip muscular strength balance is associated with running economy in recreationally-trained endurance runners

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5219
Author(s):  
Wallace A. Silva ◽  
Claudio Andre B. de Lira ◽  
Rodrigo L. Vancini ◽  
Marilia S. Andrade
Keyword(s):  
Oxygen Uptake ◽  
Body Mass ◽  
Muscular Strength ◽  
Peak Torque ◽  
Running Economy ◽  
Fat Free Mass ◽  
Isokinetic Strength ◽  
Total Body Mass ◽  
Total Body ◽  
Hip Flexor

Background The percentage of sustained maximal oxygen uptake and the running economy are important factors that determine the running success of endurance athletes. Running economy is defined as the oxygen uptake required to run at a given speed and depends on metabolic, cardiorespiratory, biomechanical, neuromuscular, and anthropometric factors. With regard to anthropometric characteristics, total body mass seems to be a crucial factor for the running economy. Moreover, neuromuscular components, especially knee muscular strength and the strength balance ratio, also seem to be critical for the running economy. In addition to knee muscle strength, hip muscle strength is also an important contributor to running performance on level or hilly ground. However, the relationship between running economy and the hip muscles is unknown. Thus the aim of the present study was to verify whether hip flexor and extensor isokinetic peak torque, the isokinetic strength balance ratio, total body mass and fat free mass were associated with running economy in both sexes and to compare sex differences in physical fitness and isokinetic strength characteristics. Methods A total of 24 male (31.0 ± 7.7 years, 176.2 ± 7.3 cm, and 70.4 ± 8.4 kg) and 15 female (31.3 ± 6.7 years, 162.9 ± 3.9 cm, and 56.0 ± 5.3 kg) recreationally-trained endurance runners were recruited. Maximal oxygen uptake, running economy, conventional (concentric flexors-to-concentric extensors) and functional (concentric flexors-to-eccentric extensors) hip isokinetic strength balance ratios, peak torque of the hip flexor and extensor muscles, total body mass, and fat-free mass were measured. Running economy was assessed on two separate days by means of the energy running cost (Ec) using a motorized treadmill at 10.0 and 12.0 km h−1 (3% gradient) and 11.0 and 14.0 km h−1 (1% gradient). Results The functional balance ratio was significantly and negatively associated with Ec at 11.0 (r =  − 0.43, P = 0.04) and 12.0 km h−1 (r =  − 0.65, P = 0.04) when using a 3% gradient in male runners. Considering muscular strength, male runners only showed a significant relationship between Ec (assessed at 12 km h−1 and a 3% gradient) and peak torque for extensor muscle eccentric action (r = 0.72, P = 0.04). For female runners, only peak torque relative to total body mass for extensor muscles (180° s−1) was positively associated with Ec when assessed at 10 km h−1 using a 3% gradient (r = 0.59, P = 0.03). No significant relationships were found between Ec and total body mass or fat-free mass. Discussion Given that the functional balance ratio was associated with a better Ec, coaches and athletes should consider implementing a specific strengthening program for hip flexor muscles to increase the functional ratio.

scholarly journals Standardized MET Value Underestimates the Energy Cost of Treadmill Running in Men

2017 ◽  
Vol 38 (12) ◽  
pp. 890-896
Author(s):  
Helouane Ázara ◽  
Paulo Farinatti ◽  
Adrian Midgley ◽  
Fabrício Vasconcellos ◽  
Patrícia Vigário ◽  
...  
Keyword(s):  
Body Mass ◽  
Energy Cost ◽  
Fat Free Mass ◽  
Treadmill Running ◽  
Metabolic Equivalent ◽  
Total Body Mass ◽  
Healthy Men ◽  
Energy Cost Of Running ◽  
The Mean ◽  
Total Body

AbstractThe main purpose of the present study was to compare the reference metabolic equivalent (MET) value and observed resting oxygen uptake (VO2) for defining cardiorespiratory fitness (VO2max) and characterizing the energy cost of treadmill running. A heterogeneous cohort of 114 healthy men volunteered to participate. In Part 1 of the study, 114 men [mean±SD, age: 24±5 years; height: 177.1±7.9 cm; body mass: 75.0±10.0 kg] visited the laboratory twice for assessment of resting and maximal VO2 values to compare the reference MET value vs. observed resting VO2 and to investigate the association between resting VO2 and VO2max. In Part 2, 14 of the 114 men visited the laboratory once more to perform a 30-min bout of running at 8.0 km∙h−1/8.3 METs. The mean observed resting VO2 of 3.26 mL·kg−1·min−1 was lower than the reference MET value of 3.5 mL·kg−1·min−1 (P<0.001). Resting and maximal VO2 values relative to total body mass and fat-free mass were positively correlated (R=0.71 and 0.60, respectively; P<0.001). The maximal MET and energy cost of treadmill running were consequently underestimated when calculated using the reference MET value only for those with low VO2max (P=0.005 to P<0.001). In conclusion, the reference MET value considerably overestimated observed resting VO2 in men with low VO2max, resulting in underestimations of the maximal MET, exercise intensity prescription, and the energy cost of running.

scholarly journals Multilevel allometric modelling of maximal stroke volume and peak oxygen uptake in 11–13-year-olds

2019 ◽  
Vol 119 (11-12) ◽  
pp. 2629-2639 ◽  
Author(s):  
Neil Armstrong ◽  
Jo Welsman
Keyword(s):  
Sex Differences ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Sex Difference ◽  
Multilevel Models ◽  
Peak Oxygen Uptake ◽  
Fat Free Mass ◽  
Treadmill Running ◽  
Additional Contribution ◽  
Carbon Dioxide Rebreathing

Abstract Purpose To investigate (1) whether maximal stroke volume (SVmax) occurs at submaximal exercise intensities, (2) sex differences in SVmax once fat-free mass (FFM) has been controlled for, and, (3) the contribution of concurrent changes in FFM and SVmax to the sex-specific development of peak oxygen uptake $$ \left( {{\dot{\text{V}}\text{O}}_{2} } \right) $$V˙O2. Methods The peak $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2 s of 61 (34 boys) 11–12-year-olds were determined and their SV determined during treadmill running at 2.28 and 2.50 m s−1 using carbon dioxide rebreathing. The SVmax and peak $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2 of 51 (32 boys) students who volunteered to be tested treadmill running at 2.50 m s−1 on three annual occasions were investigated using multilevel allometric modelling. The models were founded on 111 (71 from boys) determinations of SVmax, FFM, and peak $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2. Results Progressive increases in treadmill running speed resulted in significant (p < 0.01) increases in $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2, but SV levelled-off with nonsignificant (p > 0.05) changes within ~ 2–3%. In the multilevel models, SVmax increased proportionally to FFM0.72 and with FFM controlled for, there were no significant (p > 0.05) sex differences. Peak $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2 increased with FFM but after adjusting for FFM0.98, a significant (p < 0.05) sex difference in peak $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2 remained. Introducing SVmax to the multilevel model revealed a significant (p < 0.05), but small additional effect of SVmax on peak $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2. Conclusions Fat-free mass explained sex differences in SVmax, but with FFM controlled for, there was still a ~ 5% sex difference in peak $$ {\dot{\text{V}}\text{O}}_{2} $$V˙O2. SVmax made a modest additional contribution to explain the development of peak $$ {\dot{\text{V}}\text{O}}_{2} , $$V˙O2, but there remained an unresolved sex difference of ~ 4%.

Exploring the physiological determinants of marathon performance

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
G Christou ◽  
E Pagourelias ◽  
A Deligiannis ◽  
E Kouidi
Keyword(s):  
Body Weight ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Right Ventricular ◽  
Body Fat ◽  
Running Economy ◽  
Body Fat Percentage ◽  
Fat Percentage ◽  
Marathon Race ◽  
Marathon Performance

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ESPA 2014-2020 Background/Introduction: Long-time endurance exercise training leads to cardiovascular, respiratory, haematological and neuromuscular adaptations. The relative contribution of these adaptations to running performance in long-distance races remains to be elucidated in an integrative manner. Purpose The study of the relationship of marathon performance with anthropometric, cardiorespiratory and haematological adaptations. Methods Thirty-one marathon runners (26 males, age: 42 ± 9 years) were examined within 3 weeks before Athens marathon race (42.195 km). Assessment of training characteristics, anthropometric measurements, including height, body weight and body fat percentage, echocardiographic study, cardiopulmonary exercise testing using treadmill ergometer and blood test were performed. Results Training age was 11(1-39) years. Body fat percentage(BFP) was 17.3 ± 7.1% and body weight-indexed maximum oxygen uptake(VO2max) was 52.6 ± 8.9 mL/kg/min. Marathon race time(MRT) was 3:59:01(2:47:17-5:31:32). Among anthropometric measurements, MRT was positively associated with BFP(r= 0.561, p = 0.002) and body fat mass(r = 0.514, p = 0.005), even after adjustment for VO2max or oxygen uptake at first(VO2-VT1) or second(VO2-VT2) ventilatory threshold, implying an effect of BFP on running economy. Among echocardiographic parameters, MRT correlated negatively with right ventricular end-diastolic area(RVEDA) (r = -0.707, p &lt; 0.001) and ratio of early to late diastolic transtricuspid flow velocity(TVE/A) (r= -0.430, p = 0.025). MRT correlated negatively with body weight-indexed VO2max (r= -0.692, p &lt; 0.001), VO2-VT1 (r= -0.426, p = 0.019) and VO2-VT2 (r= -0.688, p &lt; 0.001). MRT correlated negatively with maximum minute ventilation(VEmax) (r= -0.418, p = 0.022), VEmax indexed for body surface area(BSA) (r= -0.456, p= 0.011), maximum tidal volume(Vtmax) indexed for BSA(r= -0.436, p = 0.018) and oxygen uptake efficiency slope(OUES) (r= -0.529, p = 0.003). MRT was not associated with haemoglobin concentration. RVEDA correlated positively with maximum oxygen pulse (r = 0.653, p = 0.001), which is an estimate of stroke volume during exercise, and OUES(r = 0.534, p = 0.009). After performing multivariate linear regression analysis with MRT as dependent variable and BFP(standardized β=0.495, p = 0.001), RVEDA(standardized β= -0.550, p = 0.001) and Vtmax indexed for BSA(standardized β= -0.110, p = 0.418) as independent variables, only BFP and RVEDA were significant independent predictors of MRT(adjusted R2 = 0.667, p &lt; 0.001 for the model). Conclusions The results of the present study demonstrated that the main cardiorespiratory adaptation that could predict a better marathon performance was right ventricular dilatation, through the increase in stroke volume during exercise, whereas upregulation of tidal volume during exercise was found to be a weaker predictor. The principal anthropometric determinant of marathon performance appears to be body fat percentage, via the influence on running economy. Abstract Figure 1

Serum leptin levels during recombinant human GH therapy in adults with GH deficiency

1997 ◽  
Vol 137 (6) ◽  
pp. 650-654 ◽  
Author(s):  
YJ Janssen ◽  
M Frolich ◽  
P Deurenberg ◽  
F Roelfsema
Keyword(s):  
Body Fat ◽  
Fat Mass ◽  
Fat Free Mass ◽  
Hormone Deficiency ◽  
Body Fat Percentage ◽  
Fat Percentage ◽  
Gh Therapy ◽  
Baseline Serum ◽  
Serum Leptin ◽  
Total Body

OBJECTIVE: Recent studies suggest an involvement of the obese (OB) gene and its product leptin in the regulation of body fat. Since adults with growth hormone deficiency (GHD) have a high body fat mass which can be normalized with recombinant human (rh) GH therapy, we investigated whether GH influences serum leptin directly or indirectly via its lipolytic effect. DESIGN: Fourteen adults with GHD were treated with subcutaneous injections of rhGH given every evening for 52 weeks. Serum leptin, fat mass and body fat percentage were measured at baseline and after 4 and 52 weeks of treatment. METHODS: Serum leptin was measured with a commercially available RIA. Total body water was determined by dilution of deuterium. Fat free mass was estimated by assuming a hydration of 73%. Fat mass was estimated by subtracting fat free mass from weight. RESULTS: At baseline, serum leptin levels were exponentially related to body fat percentage (r = 0.88; P < 0.0005). rhGH treatment for 4 weeks did not significantly influence serum leptin levels, whereas treatment for 52 weeks significantly decreased serum leptin levels (15.6 +/- 2.9 to 10.8 +/- 2.1 micrograms/l; P = 0.020). Fat percentage was significantly decreased after 52 weeks of treatment (37.6 +/- 2.1 to 33.8 +/- 2.5%; P < 0.0005). The decrease in serum leptin could largely be explained by the decrease in body fat percentage, whereas the relation between leptin and body fat percentage did not change. CONCLUSIONS: The influence of GH on serum leptin in indirect, via its effect on body fat percentage.

scholarly journals Ethnic and sex differences in visceral, subcutaneous, and total body fat in children and adolescents

Obesity ◽  
2013 ◽  
Vol 21 (6) ◽  
pp. 1251-1255 ◽  
Author(s):  
A. E. Staiano ◽  
S. T. Broyles ◽  
A. K. Gupta ◽  
P. T. Katzmarzyk
Keyword(s):  
Sex Differences ◽  
Children And Adolescents ◽  
Body Fat ◽  
Total Body Fat ◽  
Total Body

scholarly journals Body mass index and waist circumference are better predictors of insulin resistance than total body fat percentage in middle-aged and elderly Taiwanese

Medicine ◽  
2017 ◽  
Vol 96 (39) ◽  
pp. e8126 ◽  
Author(s):  
Yiu-Hua Cheng ◽  
Yu-Chung Tsao ◽  
I-Shiang Tzeng ◽  
Hai-Hua Chuang ◽  
Wen-Cheng Li ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Mass Index ◽  
Waist Circumference ◽  
Body Mass ◽  
Body Fat ◽  
Body Fat Percentage ◽  
Middle Aged ◽  
Fat Percentage ◽  
Total Body Fat ◽  
Total Body

The Influence of Age, Sex and Body Mass Index on the Effectiveness of Brisk Walking for Obesity Management in Adults: A Systematic Review and Meta-Analysis

2017 ◽  
Vol 14 (5) ◽  
pp. 389-407 ◽  
Author(s):  
Leon Mabire ◽  
Ramakrishnan Mani ◽  
Lizhou Liu ◽  
Hilda Mulligan ◽  
David Baxter
Keyword(s):  
Body Mass Index ◽  
Body Weight ◽  
Waist Circumference ◽  
Body Fat ◽  
Fat Mass ◽  
Fat Free Mass ◽  
Body Fat Percentage ◽  
Brisk Walking ◽  
Obesity Management ◽  
Fat Percentage

Background:Brisk walking is the most popular activity for obesity management for adults. We aimed to identify whether participant age, sex and body mass index (BMI) influenced the effectiveness of brisk walking.Methods:A search of 9 databases was conducted for randomized controlled trials (RCTs). Two investigators selected RCTs reporting on change in body weight, BMI, waist circumference, fat mass, fat-free mass, and body fat percentage following a brisk walking intervention in obese adults.Results:Of the 5072 studies screened, 22 met the eligibility criteria. The pooled mean differences were: weight loss, –2.13 kg; BMI, –0.96 kg/m2; waist circumference, –2.83 cm; fat mass, –2.59 kg; fat-free mass, 0.29 kg; and body fat percentage, –1.38%. Meta-regression of baseline BMI showed no effect on changes.Conclusions:Brisk walking can create a clinically significant reduction in body weight, BMI, waist circumference, and fat mass for obese men and women aged under 50 years. Obese women aged over 50 years can achieve modest losses, but gains in fat-free mass reduce overall change in body weight. Further research is required for men aged over 50 years and on the influence of BMI for all ages and sexes.

Magnitude and variation of ratio of total body potassium to fat-free mass: a cellular level modeling study

2001 ◽  
Vol 281 (1) ◽  
pp. E1-E7 ◽  
Author(s):  
Zimian Wang ◽  
F. Xavier Pi-Sunyer ◽  
Donald P. Kotler ◽  
Jack Wang ◽  
Richard N. Pierson ◽  
...  
Keyword(s):  
Body Fat ◽  
Essential Element ◽  
Physiological Model ◽  
Cellular Level ◽  
Fat Free Mass ◽  
Total Body Potassium ◽  
Fluid Compartment ◽  
Total Body Fat ◽  
Total Body ◽  
Living Organisms

Potassium is an essential element of living organisms that is found almost exclusively in the intracellular fluid compartment. The assumed constant ratio of total body potassium (TBK) to fat-free mass (FFM) is a cornerstone of the TBK method of estimating total body fat. Although the TBK-to-FFM (TBK/FFM) ratio has been assumed constant, a large range of individual and group values is recognized. The purpose of the present study was to undertake a comprehensive analysis of biological factors that cause variation in the TBK/FFM ratio. A theoretical TBK/FFM model was developed on the cellular body composition level. This physiological model includes six factors that combine to produce the observed TBK/FFM ratio. The ratio magnitude and range, as well as the differences in the TBK/FFM ratio between men and women and variation with growth, were examined with the proposed model. The ratio of extracellular water to intracellular water ( E/I) is the major factor leading to between-individual variation in the TBK/FFM ratio. The present study provides a conceptual framework for examining the separate TBK/FFM determinants and suggests important limitations of the TBK/FFM method used in estimating total body fat in humans and other mammals.

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