Specific Populations - Youth

Represents the maximum amount of oxygen that can be extracted from the atmosphere, transported to the working muscle, and taken up and utilized by the exercising tissue. 1

Measured in Absolute: L.min-1 Ratio scaled (divide by body mass): ml.kg-1.min-1 In children and young people, allometric scaling: ml.kg-0.67.min-

Sets the limit for ATP generation using oxygen dependent (‘aerobic’) metabolic pathways; therefore has an important influence of performance Maximal oxygen uptake seems to be linked to markers of health independent of other risk factors e.g. ‘fit but fat’

Plateau’s: only a minority of children and young people attain – and hence use of the term ‘peak’ oxygen uptake in the paediatric literature

Heart rate will be higher than adults The RER will be lower as a result of lactate not being produced in higher volumes compared to adults

More muscle mass as you age = higher VO2 Males will also have a higher VO2 levels as a result of having testosterone levels compared to women Body mass in this context isnt takwen into account

Some girls can have puberty at the age of 9 Lower VO2 for girls as a result of also more fat development

Peak VO 2 gradually increases in males (0.25 L.min-1 per year) Peak VO 2 gradually increases in females (0.125 L.min-1 per year) but perhaps levels off, even falls at 13-15 years Male values higher than females (10 years: 2-10%; 14 years: 27-31%; 16 years: 37%) women half then men along with a decrease

Boys have greater muscle mass resulting in: * Facilitates the utilisation of oxygen (more muscle, more places) * Peripheral muscle pump helps with venous return to heart, boosting Stroke Volum (SV) Increases in Haemoglobin (Hb) concentration during late teens * more muscles = higher haemoglobin concetration Biological maturation * Independent of chronological age, body size, muscle mass and Hb concentration * Older males > Older females Physical activity * males are more active

• The initial model revealed mass, stature and age as significant explanatory variables of VO2, peak with an additional positive effect for stage of maturity. • Girls’ values were significantly lower than those of boys and a significant age-by-sex interaction described a progressive divergence in boys’ and girls’ VO2, peak. Fat-free mass was the dominant influence on the growth of VO2, peak but the multilevel regression models demonstrated that, with body size and fatness allowed for, VO2, peak increased with age and maturation in both sexes Fat = less VO2

VO, peak boys, 47.2 $ 6.1; girls, 40.4 $ 5.8 mL/kg/min - 16.8% difference Maximal stroke index boys, 62 + 9; girls 55 + 9 mL/m - 12.7% difference Conclusions: SV and body composition contribute to sex-related variations in VO2, max * Unclear if due to sex differences in relative heart size or dynamic factors influencing ventricular preload and contractility during exercise

VO, peak Boys 47.9 mL/kg/min Girls 40.9 mL/kg/min Boys 19.0 mL/kg LBM(1.33)/min Girls 18.9 mL/kg LBM(1.33)/min normalized (allometric equation) the difference totally disappeared Maximal SV was significantly higher in boys than in girls - but when expressed relative to LBM, the difference was no longer significant. Conclusions: * Contrary to adults, lower SV max was the sole limiting factor of VO, max that distinguished boys from girls * This difference disappeared when normalised for LBM

Girls required a greater fractional O2 extraction to increase work rate and O2 extra tian compared it laya in during ramp exercise more muscle = more oxygen uptake Conclusions: To 10-y-f children is in part, in 9- related to sex-specific changes in muscle O2, extraction dynamics during incremental exercise

Higher maximal cardiac output Higher blood and plasma volume Higher haemoglobin concentrations Higher stroke volume Decreased heart rate Larger myocardial mass and heart volume? Increased lung function Less blood lactate levels compared to adults and untrained youths

“trigger point” – Katch (1983) Young people 8 to 10 Average increase in mass related peak oxygen uptake 6.5% Young people 11 to 18 Average increase in mass related peak oxygen uptake 5.5 to demonstrate a increase due to training is really difficult because you might see changes due to growth & a lot of young people are fit and active anyways Pre and pubertal children do get benefits from exercise

At the moment no evidence to suggest a difference as a result of a lack of testing Problems with this conclusion? * hasnt been looked at within studies * theres very few studies for female

Central factors of heart size and peak cardiac output are proportional to the LBM of the individual and sex independent. Sex differences in peripheral factors such as muscle fibre type profile, may affect AVO2 difference and underlie prepubertal boys’ higher peak V O2 How good are you at extracting oxygen from the capilaries

Mode, Frequency, Duration, Intensity and Programme length Mode: The mode of delievery ie intervals

Both

a variety of exercise modes have been undertaken • Continuous exercise • Interval • Mix of two • Cycling, running, resistance exercise Exercise using large muscle groups regardless of mode has the potential to increase peak oxygen uptake

How often per week sessions occur

How long the sessions will last

How intense a programme is in terms of heart rate

how long the programme is