Vladimir Ilic

Walking at speeds close to the preferred transition speed as an approach to obesity treatment.

INTRODUCTION Increasing energy expenditure through certain exercise is an important component of effective interventions to enhance initial weight loss and prevent weight regain. OBJECTIVE The purpose of this study was to determine the effect of a 16-week weight loss exercise programme on morpho-functional changes in female adults and to examine the programme effects on two subpopulations with different levels of obesity. METHODS Fifty-six middle-aged women were divided into 2 groups according to their body mass index (BMI): 25-29.9 kg/m2--overweight (OW) and > or =30 kg/m2--obese (OB). The exercise protocol included a walking technique based on hip rotation at horizontal plane at speeds close to the preferred transition speed (PTS). At the initiation of the study and after 16 weeks of the programme, anthropometric, morphological and cardiovascular parameters of all subjects were assessed. The main effects of Group (OW and OB) and Time and the interaction effect of Group by Time were tested by time repeated measures general linear model (mixed between-within subjects ANOVA). RESULTS Mean weight loss during the programme was 10.3 kg and 20.1 kg in OW and OB, respectively. The average fat mass (FM) loss was 9.4 kg in OW and 16.9 kg in OB. The mixed ANOVA revealed a significant group by time interaction effects for waist circumference, body weight, body water, fat free mass, FM, %FM and BMI (p < 0.05). CONCLUSION The applied exercise protocol has proved as beneficial in the treatment of obesity, since it resulted in a significant weight loss and body composition changes. The reduction in body weight was achieved mainly on account of the loss of fat mass.

The relationship between hip, knee and ankle muscle mechanical characteristics and gait transition speed

The purpose of the present study was to explore the relationship between mechanical characteristics of hip, knee and ankle extensor and flexor muscle groups and gait transition speed. The sample included 29 physically active male adults homogenized regarding their anthropometric dimensions. Isokinetic and isometric leg muscle mechanical characteristics were assessed by an isokinetic dynamometer, while individual walk-to-run (WRT) and run-to-walk transition speeds (RWT) were determined using the standard increment protocol. The relationship between transition speeds and mechanical variables scaled to body size was determined using Pearson correlation and stepwise linear regression. The highest correlations were found for isokinetic power of ankle dorsal flexors and WRT (r=.468, p<.01) and the power of hip extensors and RWT (r=.442, p<.05). These variables were also the best predictors of WRT and RWT revealing approximately 20% of explained variance. Under the isometric conditions, the maximal force and rate of force development of hip flexors and ankle plantar flexors were moderately related with WRT and RWT (ranged from r=.340 to .427). The only knee muscle mechanical variable that correlated with WRT was low velocity knee flexor torque (r=.366, p<.05). The results generally suggest that the muscle mechanical properties, such as the power of ankle dorsal flexors and hip extensors, influence values of WRT and RWT.

The relationship between allometry and preferred transition speed in human locomotion

The purpose of this study was to explore the relationships between preferred transition speed (PTS) and anthropometric characteristics, body composition and different human body proportions in males. In a sample of 59 male students, we collected anthropometric and body composition data and determined individual PTS using increment protocol. The relationships between PTS and other variables were determined using Pearson correlation, stepwise linear and hierarchical regression. Body ratios were formed as quotient of two variables whereby at least one significantly correlated to PTS. Circular and transversal (except bitrochanteric diameter) body dimensions did not correlate with PTS. Moderate correlations were found between longitudinal leg dimensions (foot, leg and thigh length) and PTS, while the highest correlation was found for lower leg length (r=.488, p<.01). Two parameters related to body composition showed weak correlation with PTS: body fat mass (r=-.250, p<.05) and amount of lean leg mass scaled to body weight (r=.309, p<.05). Segmental body proportions correlated more significantly with PTS, where thigh/lower leg length ratio showed the highest correlation (r=.521, p<.01). Prediction model with individual variables (lower leg and foot length) have explained just 31% of PTS variability, while model with body proportions showed almost 20% better prediction (R(2)=.504). These results suggests that longitudinal leg dimensions have moderate influence on PTS and that segmental body proportions significantly more explain PTS than single anthropometric variables.

Planning implementation of method of observation in social sciences

The paper deals with the problems while planning the application of method of observation as the primary method for data collection. These include determining the objectives, theoretical and operational elaboration of the research plan and collection of initial evidence from other sources of data that can be used to successfully plan research mainly based on observation. In the first section of the paper it is pointed to the unjustified overemphasis of differences between participatory and non-participatory forms of observation in its planning. The second section shows the possibility of its application to other sources and methods of data collection when planning observations. Special attention is paid to the role of interview and sequential analysis. In the third section, the issues of preparing data analysis in the planning of observation are specifically discussed. The fourth section shows the specificity of the planning of observation, depending on the nature of the data. We also considered the concretization of the plan of observation, including the selection of size, location and time for performing monitoring and positioning one or more observers. The fifth section briefly points to some suggestions about training observers. The concluding section of the paper deals with planning during the observations, with emphasis on grounded theory.