Antropomotoryka nr 51 - Akademia Wychowania Fizycznego w ...

The physiological cost of walking in overfat girlsselection of intensity of walking and running effort forchildren, besides such aspects as period of development(economy of exercise of locomotion nature ismuch better in postpubertal children than in prepubertalones [25]), or percentage of body fat, differentiationbetween genders should also be considered.These considerations should also emphasize economyof walking and running effort determined throughassessment of oxygen consumption or level of oxygenintake observed during functional equilibrium for thegiven walking or running speeds at submaximal intensity[26, 27, 28, 29]. During investigations of children,running economy is mainly expressed as a value ofoxygen intake during exercise with a particular, submaximalintensity. Rowland et al. [26] show that thismeasure in children in prepubertal phase of developmentcan be formed by the level of VO 2· kg –1 recordedduring running at the speed of 9.6 km · h –1 or the valueof ∆VO 2· kg –1 induced by the speed increment of1.6 km · h –1 . Running economy can be also determinedbased on assumption of linear relationship betweenrunning speed and VO 2oxygen intake. To achieve this,the physiological cost to cover 1 kilometre based onoxygen intake during running effort at submaximalintensity is estimated. The physiological cost determinedusing this procedure estimated by McMiken andDaniels [30] amounted to nearly 200 m · kg –1 of bodymass per 1 km of covered distance. It is generally acceptedthat running economy in children is much lowerthan in young people or adults, which involves higherphysiological cost of exercise [31, 32, 25]. The results ofstudies by Donkervilet et al. [25] show that running andwalking economy is markedly different between sexeseven in children at younger age. Girls at the age of tenwere characterized by better economy of both walkingand running effort, which was caused by better motorcoordination. Higher values of oxygen intake recordedin boys during walking exercise by Gradek and Cempla[14] in relation to girls and higher relative load in boysexpressed in %VO 2max might point to enhanced walkingeconomy in girls.Silva and Lopes [33] reported that frequent obesityand higher blood pressure is connected with reducedlevel of daily physical activity. Children who commuteto schools using public transportation, scooters or carsshow excessive body mass and adipose tissue considerablymore frequently than their peers who travel toschools by walking or cycling. However, according toSallis and Glanz [34], modern transportation and urbansolutions limit daily physical activity. Large distancesbetween schools and homes, lack of pavements andcycle lanes cause that it is faster and safer for childrento get to school using public transportation or cars ratherthan by walking or cycling. Thus, it is more and more oftenemphasized that efficiency of prevention and treatingobesity can be based only on slimming programswhose efficiency is often insignificant and the obtainedeffects are maintained for only a short period of time.It is also highlighted that promotion of healthy lifestylesshould encompass, among other things, adaptation ofcommunication and urban solutions in a way that allowsfor safe, physically active commuting to school or workand ensuring conditions for physical recreation, whichis of particular importance in large agglomerations.To sum up, locomotion effort constitute a natural formof movement which involves all large muscle groups.However, during these type of exercise, obese childrenmust carry additional body mass, which is connected,among other things, with joint overload. However, givingup public transportation or cars used for commutingto schools or work might impact, through children’sincreased amount of daily physical activity, on reductionin excessive body mass. Movement-related gamesbased on running or walking forms of physical exerciseare also a big attraction for children, therefore they canbe enjoyable alternative to a monotonous slimmingtherapies and might contribute to the increase in timespent each day on physical activity.ConclusionsThe cost of physical exercise during walking effort ishigher in girls with excessive body fat. This fact is confirmedby higher values of %VO 2max recorded at thesame intensities of test effort. Dynamics of changes inphysiological parameters during walking effort, whenexcess body mass contributed to higher physiologicalload in girls with excessive adipose tissue, were similarin both groups but they maintained at significantlydifferent levels. Most of the analysed physiological parameterswere at higher level in girls with excess bodyfat. Intensity of exercise considerably affected thevalue of intergroup differences in the level of physiologicalparameters. The reason for this (apart fromadditional load in the form of excess body fat carriedduring this form of exercise performed by overweightgirls) might be the method of load selection, comparablefor all the girls in terms of locomotion speed butwithout consideration of individual effort-related abilitiesof the body.– 77 –