PESP - CRF in YP pt2

bethdrysdale94's version from 2017-05-23 11:19

Section 1

Question Answer
Why does VO2 value in young people increase over time regardless of CRF?increases as young people grow - progressive enlargement of system components that determine peak VO2 (L/min)
What drives developmental changes in peak VO2?skeletal muscle mass and oxidative enzyme activity
What % does muscle mass increase to in boys and girls from 5y to 17y?boys 42 to 53%. girls 40 to 45%
Why is expression of VO2 important regarding young people?L/min is inefficient because no scaling factor. ml/kg/min is flawed because scaling factor is inaccurate. In an ideal world, ml/skeletal muscle mass kg/min is best measure
Armstrong and Welsman 1994: absolute VO2(L/min) max trends from 8-16y in boys and girlsboys overall have higher VO2 than girls. boys and girls increase, boys continue to increase above girls (growth spurt?) girls plateau around 14-16y. heterogenous values
Armstrong and Welsman 1994: Ratio scaled VO2 trend boys and girls aged 8to16yboys VO2 remains the same when ratio scaled (ml/kg/min) where as girls VO2 is steady then decreases - arguments about when that happens (10y? 13y?)

Section 2

Question Answer
Welsman JR et al 1996: allometric scaling VO2 development in boys and girlsboys and girls increase from 11 to 13y. boys continue to increase and girls plateau at 13 to 22y. males > females (divergent difference)
what is a secular trend?population change in something over a long period of time.
Armstrong et al 2011: performance vs fitness testingfitness = O2 uptake measures. performance = eg shuttle run tests
Armstrong et al 2011: secular trends in CRF boys trendsPerformance decrease over time where as fitness increases over time (1990s considered 100%)
Armstrong et al 2011: secular trends in CRF girls trendsfitness peaked in 1960s, gradual decline which ties in with performance decline
Armstrong et al 2011: secular trends in CRF overall changeno evidence that CRF is changing (d=-0.06) however large decline in shuttle run tests (d=-0.99). CANT PERFORM BUT PHYSIOLOGICAL ABILITY TO PERFORM - maybe they dont want to

Section 3

Question Answer
Rowland TW 2002: how much variance did body fat account for in 1 mile run time?31%
Rowland TW 2002: how much variance did CRF account for in 1 mile run time?28%
Rowland TW 2002: body fat and CRF variance summaryboth account for around the same amount so they are both as important as the other. adiposity needs to be accounted for. best combination - low body fat and high CRF.
Rowland TW 2002: describe pathwayincreased caloric intake leads to obesity and so does decreased physical activity. does obesity then affect fitness or does it decrease physical activity that then leads to decreased fitness? or does decreased fitness lead to decrease in PA which leads to obesity?

Section 4

Question Answer
Sandercock et al 2015: limitationscross sectional studies, different cohorts of children, used a performance test instead of a physiological measure (shuttle run instead of VO2)
Sandercock et al 2015: results 1998-2008boys CRF fitness decreased in first 10 years by 7% and BMI increased by 4%. girls CRF decreased by 7% but BMI decreased by -1%.
Sandercock et al 2015: results 2008-2014boys CRF decreased by 8%, BMI decreased 2%. girls CRF decreased by 4%, BMI increased by 1%
Sandercock et al 2015: overall results 1998-2014boys CRF 15% decrease, BMI 2% increase. girls CRF 11% decrease, BMI 0% change.
Sandercock et al 2015: overviewboys vs girls CRF vs BMI - CRF measured by shuttle run test scores.

Section 5

Question Answer
what conclusions can be drawn from CRF cut-points table?difficult to define what is fit enough (disease markers present in adults not in children). no internationally recognised lower limit for CRF. boys lower limit is higher than for girls (muscle mass, VO2 genetics, disease markers). wide variation amongst studies.