Differences in oxygen uptake (VO2) relative to body mass between children and adults walking or running at a given speed might be the result of body size differences. In order to determine whether body size is the main factor affecting these differences in VO2 per kg, we investigated treadmill economy in 10 female adolescents (girls) and 10 women who were matched for body size. There were no significant differences between groups in anthropometrics, stride frequency, or VO2peak. Mean mass-specific VO2 was not significantly different during walking (girls: 12.3 ± 1.7 ml·kg-1·min-1; women: 10.9 ± 1.4 ml·kg-1·min-1) or running (girls: 30.5 ± 3.5 ml·kg-1·min-1; women: 29.0 ± 2.0 ml·kg-1·min-1). Body size appears to have the largest effect on oxygen cost differences usually seen between girls and women during locomotion.
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Effect of Body Size on Treadmill Economy in Female Adolescents and Adults
Colleen M. Grossner, Emily M. Johnson, and Marco E. Cabrera
Factors Contributing to the Energy Expenditure of Youth during Cycling and Running
Robert G. McMurray, Joanne S. Harrell, Shrikant I. Bangdiwala, Shibing Deng, and Chris Baggett
This study evaluated factors that contribute to the increased energy cost of locomotion in youth. The subjects were 321 8-18-year-old youth, similar dispersed by age and sex. Oxygen uptake (VO2) was measured during rest (REE), running at 8 km · h−1 and cycling at 16 km · h−1, using a COSMED K4b2 metabolic system. Developmental stage was obtained via questionnaire. Stature, body mass, and skinfolds (triceps & subscapular) were measured. Both sexes had similar absolute VO2 (mL · min−1) at rest (p = 0.065) and running (p = 0.084), but the males had a higher VO2 during cycling (p = 0.046). There were no sex differences in relative VO2 (mL · kg−1 · min−1) at rest (p = 0.083); however, the males had a higher VO2 than the females during cycling and running (p £ 0.002). Multiple regression, tested for collinearity, found that absolute VO2 during cycling and running was mostly related to fat-free mass (p = 0.0001). Similar analyses for relative VO2 (mL · kg−1 · min−1) during cycling found that fat-free mass, sex, and skinfolds were significant contributors (p ‡ 0.003). During running the relative VO2 was related to skinfolds, fat-free mass, and resting energy expenditure (p < 0.05). Neither age nor developmental stage was a significant contributor. The results indicate that the VO2 of locomotion is most closely associated with fat-free mass. Thus, to compare youth of varying age or pubertal developmental status, fat-free mass should be taken into consideration.
Age-Related Differences in Perceived Exertion While Walking and Running Near the Preferred Transition Speed
Stacey M. Kung, Philip W. Fink, Stephen J. Legg, Ajmol Ali, and Sarah P. Shultz
to their ability to anticipate when a change in their gait is required to minimize locomotive demands. The walk-to-run transition (WRT) has been shown to help optimize locomotion as gait speed changes, by reducing the mechanical load ( 3 , 14 , 20 , 21 , 26 ), improving the efficiency of the ankle
Motor Unit Firing Properties During Force Control Task and Associations With Neurological Tests in Children
Masamichi Okudaira, Ryosuke Takeda, Tetsuya Hirono, Taichi Nishikawa, Shun Kunugi, and Kohei Watanabe
daily activities such as locomotion; therefore, the current degree of FS improvement was relatively limited compared with hand muscles. Nevertheless, we showed the development of knee extensor FS with growth even with such a relatively small variation among this age group. In the present study, FS was
A Matched-Pair Analysis of Gross Motor Skills of 3- to 5-Year-Old Children With and Without a Chronic Physical Illness
Chloe Bedard, Sara King-Dowling, Brian W. Timmons, and Mark A. Ferro
score range of 0 to 60; the locomotion subscale had 89 items with a possible raw score range from 0 to 178; and the object manipulation subscale had 24 items with a total raw score range from 0 to 48. A corresponding age-standardized score was calculated for each subscale based on the raw scores. The
Optimal Drop Heights for Determining Reactive Strength Performance in Youth—Is 1 Drop Height Sufficient to Generate Trustworthy Conclusions for Training Practice?
Michael Keiner, Sebastian Möck, Hagen Hartmann, and Klaus Wirth
The stretch-shortening cycle (SSC) or reactive strength is a pivotal movement pattern in human locomotion, significantly contributing to sports performance. SSC is defined as generation of a high concentric force impulse from a decelerating or eccentric movement in the possible time, aiming to
The Effects of Exercise Serum From Prepubertal Girls and Women on In Vitro Myoblast and Osteoblast Proliferation and Differentiation
Yasmeen Mezil, Joyce Obeid, Inna Ushcatz, Sandeep Raha, and Brian W. Timmons
Exercise plays an important role in muscle and bone development. It facilitates locomotion of the musculoskeletal system, increases weight loading, and generates impact, all of which promote growth and accrual of muscle and bone, most significantly in prepubertal children ( 6 ). Data from cross
Short-Term Muscle Power Is Related to Lower Limb Muscle Volume in Young Children
Steven J. Obst, Kaysie Florance, Luke Heales, Sasha Job, and Lee Barber
locomotion and are suitable for imaging using 3D ultrasound. For each muscle, a single transverse sweep scan per trial was taken from the most proximal to distal landmarks of the muscle belly. Total scan time for each muscle was ∼10 to 12 seconds, with a between frame distance of ∼0.6 mm. Image settings were
Age, Sex, and Training Specific Effects on Cross-Education Training
Aymen Ben Othman, Saman Hadjizadeh Anvar, José Carlos Aragão-Santos, Anis Chaouachi, and David G. Behm
motor task is more challenging or novel. As children commence walking, running, and hopping (bipedal locomotion) around 1 year, they may have a greater mastery of lower limb coordination and motor control. With less experience with overloaded or challenging upper body movements, the upper body training
Poor Reliability of Measurement Instruments to Assess Acute Responses to Load in Soccer Players Irrespective of Biological Maturity Status
Ludwig Ruf, Barry Drust, Paul Ehmann, Sabrina Forster, Anne Hecksteden, and Tim Meyer
10.1519/JSC.0000000000003317 16. Frost G , Dowling J , Dyson K , Bar-Or O . Cocontraction in three age groups of children during treadmill locomotion . J Electromyogr Kinesiol . 1997 ; 7 ( 3 ): 179 – 86 . PubMed ID: 20719703 doi:10.1016/S1050-6411(97)84626-3 10.1016/S1050
