Previous reports have demonstrated that running economy (RE), a measure of efficiency of locomotion, is superior in adults than in children; however, it is unclear how these differences come to be. Purpose: To identify the effect of maturity status, physical activity and various other anatomical and physiological factors on RE development in boys aged 8 to 16 years. Methods: Data were collected as part of the Saskatchewan Growth and Development Study (SGDS; 1964-1973). Using a pure longitudinal study design, anthropometric, maturity, physiological characteristics (treadmill run) and physical activity were assessed annually for nine consecutive years. Two-hundred and two eight year-old males were measured in 1965; by 1973, complete longitudinal data were available for 63 participants. During the treadmill run, a measure of submaximal oxygen consumption (VO2) was recorded, an index of RE. Four approaches of normalizing VO2 to body size were investigated. Maturity status was determined based upon chronological age at peak height velocity (PHV). Physical activity was assessed by two teacher ratings and two questionnaires. Results: Normalizing VO2 to body surface area was found to be the most appropriate body size adjustment. Submaximal VO2 (ml/m^2/min) at 9.6 km/h decreased with increasing chronological age (p<0.05). At common chronological age bands, late-maturing boys demonstrated superior RE than early-maturing boys from ages 10-14 years (p<0.05); average-maturing boys were also found to be more efficient than early-maturers at 12 and 13 years of age (p<0.05). Physical activity was not found to have any significant effect on the development of RE (p>0.05). A series of age-specific regression analyses identified body surface area and respiratory exchange ratio (RER) as variables which account for a significant portion of the variance in absolute VO2 (0.619<R^2<0.903); RER was not significant (p>0.05) at all chronological ages. Conclusion: Determining an appropriate approach for normalizing VO2 values is essential to allow for reliable investigation into factors other than size that affect RE. Maturity status was found to significantly affect RE development; however, only during the circumpubertal years. No effect of physical activity was found on RE development in boys 8-16 years. The relative influence of maturity status and RER are variable across different ages.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-11302004-112922 |
| Date | 01 December 2004 |
| Creators | Spencer, Matthew D. |
| Contributors | Faulkner, Robert A., Drinkwater, Donald T., Baxter-Jones, Adam D. G., Unnithan, Viswanath |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-11302004-112922/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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