1 / 25

Growth and Physical Training with Reference to Heredity

Growth and Physical Training with Reference to Heredity. WEBER, G., W, KARTODIHARDJO, AND V. KLISSOXJRAS, J Appl. Physiol. 40(2): 211-215. 1976. Presented by Ryan Dalton. Background. Physiological responses to exercise vary with age Older men cannot improve as much as younger men

greta
Download Presentation

Growth and Physical Training with Reference to Heredity

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Growth and Physical Training with Reference to Heredity WEBER, G., W, KARTODIHARDJO, AND V. KLISSOXJRAS, J Appl. Physiol. 40(2): 211-215. 1976. Presented by Ryan Dalton

  2. Background • Physiological responses to exercise vary with age • Older men cannot improve as much as younger men • Can function be improved at an earlier stage of maturation vs. at a later stage?

  3. Background • Perhaps hormonal activity during growth overcomes any effects of exercise • In animal studies growth hormone causes equal increases in skeletal muscle in exercising animals and in their controls

  4. Observation • There is pronounced development in adolescents who participate in sports compared to those who do not participate • Possible causes include: Genetics, Growth, and Training at different ages.

  5. Limitations • Cross-sectional and longitudinal studies do not address how much of a factor genetics has in a child's development • The split-twin method was used to correct this problem, because each trained twin has a genotypically identical control

  6. Purpose • To study the effects of training on the oxygen transport system of children, apart from the effects of growth

  7. Methods • 12 pairs of identical twin boys were used • 4 pairs 10 years old • 4 pairs 13 years old • 4 pairs 16 years old

  8. Training • One twin exercised while the other acted as the control • 10 weeks of endurance training • 1) 3 times a week running 1 mile at maximal effort • 2) 3 times a week of continuous stepping for an average of 8.5 mins and an average heart rate of 162 beats/min

  9. Training • 3) 1 time a week cycling at 60 rpm for 3 mins which induced maximal heart rates • During recovery the work rate was reduced until heart rate returned to ~150 beats/min • “This work/recovery pattern was carried on until exhaustion”

  10. Training • On average once per week the subjects trained for hockey or rugby • The control twin continued their usual daily activities and P.E. classes

  11. Testing • Tests were conducted on a cycle ergometer before and after training • A series of progressive work loads were performed lasting for 5 min and 15 sec each, followed by a supramaximal effort of shorter duration • The twins exercised alternately motivating them to exert themselves to exhaustion

  12. Measurements • VO2 – Gas Analyzer • Blood Lactate – Arterialized sample • Heart Rate – Electrocardiogram • Cardiac Output – Estimated by CO2 rebreathing • Vital Capacity - Respirometer • Lean body weight – Predicted from skinfold measurements

  13. Results • All the variables for both twins changed • In the exercised twins: • 10 year olds – VO2 max changed significantly • 13 year olds – No significant changes • 16 year olds – VO2 max, O2 pulse, blood lactate, ventilation, respiratory frequency, and ventilation/vital capacity ratio changed significantly

  14. Discussion • The lack of change in the 13 year old groups is interesting • The possible reason for no differences between the trained and controls is that during growth spurts hormones override any effects of exercise • Other studies have supported the lack of differences between trained and control subjects of this age

  15. Extension of the study • The annual increase in the height of the 13 year olds was 8 cm • This rate of growth is expected only at the adolescent growth spurt • Because of the growth spurt the duration of training might be too short so the study was extended to a year for 3 pairs of the 13 year old twins

  16. Discussion • The old idea that training a child at their greatest rate of growth to make even greater improvements seems incorrect based on the evidence in this study • Another question is if different genotypes respond to a training stimulus at different magnitudes

  17. Discussion • According to the findings of this study improvements in VO2 max are highly based on heredity and exercise • But the findings do not support the interaction between the two

  18. Conclusion • Children of young ages respond to training apart from normal growth • During puberty the effect of training seems to be negated • Variability in VO2 max seems to be based almost entirely on heredity, but can be lessened to about 50% from influences such as training

More Related