PESP - CRF in YP pt4

bethdrysdale94's version from 2017-05-24 19:36

Section 1

Question Answer
When looking at a cross sectional study, what should you do?identify the limitations, but set out research (peak VO2 higher in trained vs untrained individuals, 14 to 24% higher). and state participant statistics.
Limitations with trained vs untrained VO2 studies (cross sectional)?most studies are done with boys. genetic influence will account for around 45% variance in VO2 (Danis et al 2003). Variable training volume details
Rowland 2005: prospective longitudinal study summary exercise training and peak VO2 - what should you look at?sample sizes, sex, duration and %change in VO2 max - what is the medium of change? mean may be skewed
more recent studies - prospective longitudinal exercise and peak VO2 factorsa lot use higher intensity exercise (kids tend to respond more physiologically to higher intensity), short duration (2-8 weeks) as trying to replicate older studies, all showed increase in VO2
overall changes in VO2 after training in children compared to adults?less capacity to increase VO2. training an untrained child vs an untrained adult, bigger %increase in adults than children - could be because training isnt right type or duration

Section 2

Question Answer
Tolfrey et al 1998: overview12 boys and 14 girls exercise training, 10 boys and 9 girls control matched. 30 mins 80% peak HR 3 times/week for 12 weeks
Tolfrey et al 1998: measurementsgroup x sex x time ANOVA analysis. accounted for change in habitual physical activity (using HR monitoring though) and change in %body fat (body size and compoisiton may have influence) (covariates, accounting for cofounding variables, as kids are likely to being stuff outside of study)
Tolfrey et al 1998: resultsCON boys - no change. CON girls - no change (slight decrease, probably measurement error). Trained boys - only small increase 1.3%. Trained girls - 8% increase but not statistically significant
Tolfrey et al 1998: discussionbaseline peak VO2 was a major factor. fitter girls in CON group than training, so it could be expected that training group may increase more because they were unfitter. when rank ordered, and %change, those who were unfit to begin with had the biggest % change. Once scaled, there were significant factors
Mahon 2008: review of literature about pretraining and percentage change VO2those who had higer VO2 had a smalle %change in VO2 after training compared with lower VO2 who had higher % change

Section 3

Question Answer
Tolfrey et al 1998: summary - boys vs girls boys > girls VO2 regardless of scaling
Tolfrey et al 1998: summary - confounding variableshabitual physical activity and %body fat needed to be accounted for
Tolfrey et al 1998: summary - baseline fitness and body composition had an influenceTrained girls baseline allometrically scaled 131ml/kg^-0.66/min and 19.3% body fat. others had more than 148 VO2 and less than 17.8% body fat
Tolfrey et al 1998: summary - baseline peak VO2 and %change valuesp=-0.31, -0.41 and -0.47 (scaling dependent) when CON and trained individuals were included. if only trained, p=-0.29, -0.37 and -0.42 ... always negative regardless of scaling

Section 4

Question Answer
Logan GRM et al 2014: HIIT summary overview - look at baseline fitness, some are only measuring performance, some measured direct and indirect VO2 - look at baseline, %change from baseline. Control group varies >>> passive, or steady state exercise, BE AWARE. some are comparing types of training, others are comparing HIIT to no exercise
Costigan et al 2015 HIIT review: isnt a great review - BUT - summarylittle evidence of heterogeneity (which would be a variation in results) so all studies saying similar things. Statistically significant, average change was mean difference = 2.6ml/kg/min and effect was large
Costigan et al 2015 HIIT review: resultsHIIT post test mean doesnt really make sense to include. 4 studies were non-significant, 5 were significant. make note of why values are so different amongst studies (some on obese children, boys, girls, etc)
Costigan et al 2015 HIIT review: forest plot average changeone study overall has an average change of 0, but some participants, declined in fitness, others increased. make note of this in studies. FIDELITY: do kids do the exercise they are asked to do? or do studies managed to get the kids to train for longer?

Section 5

Question Answer
Barker et al 2014: details2 weeks HIIT training adolescent boys (n=10) with no matched control group. 6 sessions of 4 then up to7 30s bike sprint. 4 min recovery @70rev/min (essentially wing gate tests)
Barker et al 2014: control group rationale?such a short period (2 weeks) that any change in VO2 "must" be attributed to this training because no other training will change VO2 in short period of time...... CRITIQUE - limitation, should probably always have a control group to compare against
Barker et al 2014: measurementsbefore and after 2 week training period VO2 - consider the day to day variability of VO2
Barker et al 2014: resultsgroup relative change in VO2 peak 5.4% L/min, 5.0% ml/kg/min. (2.7ml/kg/min), both possible beneficial. slight change in body mass (0.2kg, considered trivial).
downsides of HIITmainly high intensity training - muscle strain and injuries, very heavy on the body

Section 6

Question Answer
Sogndal intervention study 2011: overview102 PA vs 86 CON 9-10yo. PA = 60min daily PA lesson for 2 years. CON = 2/week 45 min PE in school.
Sogndal intervention study 2011: PA activities15 mins vigorous activity, then ball games, brisk walking, active plat, skiing, gymnastocs, relay and others.
Sogndal intervention study 2011: measurementspre and post measures: sex and baseline covariates. Peak VO2 progressive TM test (adjusted for on-line overestimation of: Douglas Bags)
Sogndal intervention study 2011: quartilesleast to most fit quartiles. least fit had biggest sig increase = 6.1%. 2nd lest fit quartile = 5.2% increase. 3rd least fit quartile = 3.8% increase. increases get lower as quartiles become fitter.
Sogndal intervention study 2011: summarychanges in peak VO2 were greater in PA than CON (+3.6ml/kg/min) (8.8%vs0.8%). Intervention had the greatest impact with the least fit children. changes adjusted for participant sex and baseline fitness. Volume of PA and frequency are crucial to change CRF.

Section 7

Question Answer
Tolfrey thinksfocus on the kids that most need fitness like in other subjects. "extra help" for those who need it
What defines peak VO2?VO2 = CO x (CaO2 - CvO2). remember CO=HRxSV
Riopel et al 1979: HRmax and VO2HR is independent of VO2, does not define it.
arterial-venous O2 difference and VO2a-v O2 diff independent of fitness and sex. ie Haemaglobin concentration and exercise blood flow unaltered by training or fitness.
SV and VO2 (rowland et al 1999 to 2011)SV is the primary factor that affects VO2. cardiac structure and function. child cyclists have bigger stroke index than untrained children but O2 conc diff is similar.