Changes in physical fitness and body build of women and men surveyed in 2004 and 2022-A longitudinal study.

Physical fitness plays a crucial role in determining human health and overall well-being. The objective of the study was to assess the changes in body structure and physical fitness among individuals examined in 2004 and 2022 (persons aged 32-34 and 50-52). The research material consists of data from the Krakow Continuous Study (KCS) of somatic development and physical fitness of people born in 1970 and 1972, conducted in Krakow in the years 1976-2022. In total, in 2004, 103 women and 122 men took part in the study, and in 2022-47 women and 67 men. Of these participants, 37 women and 53 men were present for both measurements. The following measurements were performed-physical fitness tests: handgrip strength of left and right hand, standing broad jump, sit-and-reach test and overhead medicine ball throw (2 kg); anthropometric measurements: body height, body weight and tissue composition, circumferences of the chest (relaxed and in deep inspiration), waist, hips, thigh, mid-upper-arm (MUAC, relaxed and in deep inspiration), forearm and calf, thickness of biceps, triceps, subscapular, abdominal, suprailiac and calf skinfolds; width of shoulders and hips, depth and width of the chest. A comparative analysis of the two series showed that all fitness test scores deteriorated. The percentage decrease was greater in women than in men in the tests of right and left handgrip strength and overhead medicine ball throw than in men, in the standing broad jump test similar in both sexes, in the sit-and-reach test-lower in women than in men. The greatest decreases were observed in the standing broad jump (by 14%) and the 2 kg medicine ball throw (15-12%), both in women and men. In contrast, the level of development of most of the somatic characteristics studied in 2022 was higher compared to the previous study, and, apart from body height, elbow and knee width and calf skinfold in both sexes, the differences in arithmetic means between the 2004 and 2022 series were statistically significant. Furthermore, the absence of involutionary changes in body height can be highlighted. In conclusion, the decrease in physical fitness occurring in adulthood and the increase in most somatic characteristics between 32 and 34 year-olds and 50 and 52 year-olds were confirmed.

Sexual dimorphism of adiposity and fat distribution among children and adolescents (8-18 year olds) from Poland.

OBJECTIVES: The study aimed to analyze the sexual dimorphism of total body fat [BF%] and fat distribution among 8-18 year olds from Poland. METHODS: The study included 2175 participants, divided into sex and age groups. Waist and hip circumferences, the thickness of six skinfolds, waist-to-hips ratio [WHR], the ratio of abdominal-to-suprailiac skinfolds, and the limb-to-trunk adiposity index were analyzed. Fat percentage were measured with a body composition analyzer (Tanita) with accuracy 0.1%. The Mollison's Index [MI] was used for calculating sexual dimorphism. RESULTS: The value of MI for the WHR and its components (waist and hip circumferences) was negative (the boys were characterized by higher values of these parameters). The magnitude of the sex differences was lower in the younger age groups and the highest in the oldest groups. For adiposity [BF%], the average values were higher in females. In the younger age groups, girls had thicker skinfolds compared to boys, and this tendency was also observed in the older age groups, except for abdominal and suprailiac skinfolds. The values of the analyzed adiposity indicators also represented a tendency toward central allocation of fat tissue in boys. CONCLUSIONS: In conclusion, sexual dimorphism of fat distribution and adiposity could be detected as early as 7 years of age. These differences can be identified using simple anthropometric methods, which are relatively cheap and easy to use, particularly in the field setting and large populations. The observation of changes in these features in children should be a recommended procedure aimed at early detection of overweight, obesity, as well as normal weight obesity or other metabolic disorders.

Association between physical fitness and normal weight obesity in children and adolescents from Poland.

OBJECTIVES: Normal weight obesity (NWO) is defined as elevated adiposity, despite normal body mass index (BMI). The aim of this study was to compare the results of selected fitness parameters in Polish children and adolescents from Poland with and without normal weight obesity. METHODS: The study was cross-sectional and school-based. Body height, weight and adiposity, as well as the results of selected fitness tests, were obtained. BMI was calculated, and only normal-weight individuals were included. NWO was defined as normal BMI with adiposity ≥85 percentile for age and sex. RESULTS: Children with NWO tended to have better results of absolute dynamometric strength and overhead medicine ball throw. On the other hand, when the dynamometric strength was normalized for the body mass nonNWO group achieved better results. Furthermore, NWO group had lower explosive muscle strength of the lower limbs, agility, as well as abdominal muscle strength, and endurance. CONCLUSIONS: Obtained results suggest that NWO is associated with a decrease in at least some fitness parameters in children and adolescents. Therefore, it can be hypothesized, that normal weight obesity can result in poorer fundamental motor skills. Moreover, as parameters such as muscle strength have been shown to be associated with cardiometabolic risks, described results can also be important in the context of the present and future health of the children. The results also highlight the importance of monitoring physical fitness and body composition in children, as individuals with NWO are almost indistinguishable from normal weight non-obese counterparts based on current standard surveillance protocols.

Intergenerational changes in selected cranial measurements of adolescents from Poland from 1938 to 2020.

Changes in the environment in which a particular population develops, including socio-economic factors, can influence craniofacial dimensions over time. The study aimed to investigate intergenerational changes in selected cranial measurements of adolescents (16-18 years of age) from Kraków, Poland. The analysis was based on the anthropometric measurements of four cohorts (years 1938, 1950, 2007 and 2020) of adolescents aged 16-18. Analysed characteristics included head breadth, length and head breadth-to-length ratio. The normality of each characteristic's distribution was assessed using Shapiro-Wilk's test, and the statistical significance of the differences between the cohorts was calculated using the two-way ANOVA or Kruskal-Wallis test. The pace of the secular changes of the analysed characteristics was also calculated. There was a secular increase in the head length from 1938 to 2020. The breadth of the head decreased between 1938 and 2007, but an increase was noted from 2007 to 2020. Changes analogous to head breadth were noted for the breadth-to-length ratio. The secular changes occurred the fastest between 2007 and 2020 for the length (18-year-olds), breadth (16-year old boys and 18-year-old girls) and the cephalic index (16-year old boys and 17-year-old girls). In conclusion, there was a tendency toward debrachycephalisation in the more contemporary cohorts. Observed changes may be associated with more favourable overall developmental conditions as well as possible changes in the growth tempo of the Polish population.

Intergenerational Changes in the Waist Circumference and Selected Associated Indicators among Children and Adolescents from Kraków (Poland), between 1983 and 2020.

The aim of the study was to examine the direction of the secular changes in the waist and hips circumferences, as well as selected associated body proportions, among children and adolescents from Kraków, Poland. The study group included 8-18-year-olds examined in three cross-sectional studies (1983, 2010, and 2020). The analyzed characteristics included body height, circumferences of the waist and hips, which were used to calculate Waist-to-Hip Ratio (WHR), and Waist-to-Height Ratio (WHtR). There was a secular increase regarding the majority of the analyzed features, particularly for the younger children (i.e., prepubertal/early pubertal age). The trends were also especially evident when comparing the results of the 1983 series to the results of their peers examined in 2020. An opposite trend was noted in adolescent girls. The observed changes reflect the secular trend resulting from changes in body composition and fat distribution happening due to alterations in the lifestyle and socio-economic environment of the population over the years. It should also be stressed that the increase in the studied characteristics occurred mainly in younger children. This suggests that the observed changes may have resulted from a shift in the age of maturation and also from the personal and social motivators characteristic for late adolescence.

Changes in the prevalence of underweight, overweight, obesity and excessive adiposity among adolescents from Kraków (Poland) in the years 1983-2020.

OBJECTIVES: Improved living conditions affect lifestyles and may contribute to the increased prevalence of overweight and obesity among adolescents. The aim of the study was to analyze changes in the prevalence of underweight, overweight, obesity as well as excessive adiposity among teenagers from Kraków (Poland). METHODS: The study was conducted in four series in the years: 1983, 2000, 2010, and 2020. The study group included 1759 boys and 1699 girls aged 16-18 years. body mass index (BMI) was calculated on the basis of body height and weight. Adiposity was measured by bioimpedance method. Participants were grouped according to BMI categories using Cole's cut-off points and according to adiposity based on mean and standard deviations values. The significance of the differences between cohorts was assessed by the Chi-square test. RESULTS: Secular increase in the prevalence of underweight and overweight was observed among girls in most age groups. An increase in the prevalence of high body fat was also observed among 16- and 17-year-old girls - the opposite trend was noted in 18-year-old girls. Contemporary boys had an increased prevalence of overweight and obesity in each age group. CONCLUSION: There was a significant increase in the prevalence of body weight abnormalities in the study population. The observed results may be related to socio-economic changes that adversely affect the lifestyle of the society. The results are also important in terms of the health of future generations and may be helpful in the development of new prevention and intervention programs.

Analysis of secular trends in physical fitness of children and adolescents (8-18 years) from Kraków (Poland) between 2010 and 2020.

OBJECTIVES: The aim of the study was to analyze the changes of the motor skills of children and adolescents from Kraków between 2010 and 2020. METHODS: The group included 4106 children and adolescents (8-18 years of age). The analysis of changes included results of the following fitness tests: backwards overhead medicine ball throw, standing broad jump, dynamometric strength of the hand, flexibility test, as well as shuttle run (10 × 5 m). RESULTS: A negative trend in both sexes was observed in the results of overhead medicine ball throw. The girls also had a negative intergenerational changes in the results of the shuttle run and the flexibility test. A positive secular trend was also observed in both sexes in relations to the dynamometric force of the right and left hand. In addition, the boys studied in more contemporary times showed better results in the shuttle run, compared to their peers in 2010. CONCLUSION: The study reported a decline in overall motor performance in children and adolescents. The observed results may be related to a decrease in the level of physical activity, as well as a higher incidence of overweight and high levels of body fat in the modern population.

Time trends (2010-2020) in skinfolds thickness in children and adolescents, with different BMI status, from Kraków (Poland).

Objectives: To analyse secular changes (2010-2020) in skinfold thickness in children and adolescents in different BMI categories. Methods: The study group consisted of 3-16-year olds included in two cross-sectional studies. Measurements included height, weight and 5 skinfolds. The Body Mass Index was used to categorize participants into low (underweight), normal or excess (overweight and obesity) weight groups based on IOTF cut-off points. Differences of skinfold thicknesses between both cohorts, within each of the weight status categories, were assessed using two-way ANOVA and Tukey's tests. Results: In both sexes, there was a negative secular trend in limb adiposity among the normal weight and underweight cohorts. However, in both of those subpopulations individuals examined in 2020 had greater trunk adiposity, in comparison to their counterparts examined in 2010. Declining limb adiposity was also present in the overweight category. Although, trunk adiposity among individuals with overweight was generally comparable in both cohorts. Conclusions: There was a tendency towards normal weight obesity, particularly excess abdominal adiposity, among the 2020 cohort. These findings further suggest that using only the BMI, without taking into consideration tissue composition of the body, may result in misclassification of children and adolescents with high adiposity as normal-weight.

The impact of neonatal parameters and parental factors on body fat level in early childhood.

Parental and pregnancy characteristics can affect proportions and tissue composition of the child's bodyand thereforecan influence their present and future health, as well as overall wellbeing. The aim of this study was to examine the differences between selected parental and birth-related parameters among preschool (3-7 years of age) children of varying adiposity status (n=541 girls and n=571 boys).The research was carried out in 20 randomly selected kindergartens in Krakow (Poland). Thickness of 6 skinfolds (biceps, triceps, subscapular, suprailiac, abdominal and calf) was measured. Sum of skinfolds was calculated and participants were divided into low, normal or high body fat groups. Birth-related characteristics were obtained using a questionnaire filled out by the children's parents. Children of mothers who gained the most gestational weight were characterised by high adiposity. Preschoolers with the highest birth weight, body length and head circumference had the greatest adiposity. Children of relatively younger mothers had higher body fat, in comparison to the rest of the study group. Parents of preschoolers in the high adiposity category were characterised by a greater body mass, compared to the parents of children in other body fat groups and that boys with the highest adiposity relatively more often had a close relative with obesity. Children in varying adiposity categories differed in terms of some birth-related factors. Particular attention should be paid to familial and parental characteristics, because they may influence the child's predisposition to excess adiposity deposition later in life.

Changes in the adiposity level and prevalence of overweight/obesity among children from Kraków (Poland) within the last decade (from 2010 to 2020).

The aim of this study was to assess the changes in the prevalence of overweight, obesity and high adiposity in children and adolescents from Krakow (Poland), between the years 2010 and 2020. Two cross-sectional series of anthropometric measurements were carried out in 2010 and 2020. Analysed characteristics included: body height and weight, BMI (Body Mass Index), body adiposity (%BF). The subjects were categorised according to their BMI (underweight, normal weight, overweight, obesity), as well as %BF (low, normal, high body fat).The research was conducted in randomly selected primary schools in Krakow (Poland). Studied cohorts (8-15 years of age), which represented four of the traditional residential districts: Sródmiescie, Podgórze, Krowodrza and Nowa Huta. Among the girls, there was a negative secular trend regarding the prevalence of underweight and obesity. On the other hand, there also was a positive trend concerning the prevalence of overweight and low and high body fat. In boys, there was a negative secular trend regarding the prevalence of underweight and low adiposity. There was also a generally positive secular trend regarding the prevalence of overweight, obesity as well as high adiposity in boys. The findings of this study are particularly significant because detailed knowledge of the prevalence of overweight/obesity in childhood and adolescence is crucial for the future health of entire populations. Further studies should also take into account the levels of physical fitness and activity of the examined population.

Secular changes of foot dimensions among children and adolescents (3-18 years of age).

The purpose of this study was to assess the changes in the foot dimensions in children and adolescents (3-18 years of age) from Krakow (Poland), between the years 2010 and 2020. The examined group of children and adolescents (3-18-year olds) took part in two cross-sectional surveys carried out in 2010 and 2020. The cohort examined in 2010 consisted of 1,989 females and 1,893 males and the 2020 series included 1,702 females and 1,584 males. Body height (B-v), length of the lower limbs (B-sy) foot length (pte-ap) and breadth (mtt-mtf) were measured. The last two measurements were the basis for calculating the foot index and estimated area of the foot. Generally, children examined in 2020 had relatively wider feet in proportion to their length compared to their peers from the 2010 cohort. This change was mirrored by secular trends regarding the estimated area of the foot. Additionally, a secular decrease of the length of the foot was compensated by the increasing width of this segment of the body, which among girls occurred especially after 10 years of age. The present study provides new information regarding secular changes in foot proportions among Polish children and adolescents. Results obtained in this stud are additionally significant, as there is no similar research concerning the population of Poland.

Associations of anthropometric cardiometabolic risk factors and leg fat accumulation in children and adolescents from Poland.

OBJECTIVES: To analyze the correlation between anthropometric cardiometabolic risk factors with calf adiposity in 4-16-year-olds from Poland. METHODS: Three thousand seventy-six persons (1568 girls and 1508 boys) were examined. Analyzed characteristics included body height, waist, hips and neck circumferences, body weight, six skinfolds. The following were calculated: body mass index (BMI), waist-to-hips ratio (WHR), the sum of all skinfolds, and the sum of skinfolds on the waist area. RESULTS: The relationship between the calf skinfold and the rest of the characteristics was estimated using multiple regression. There was a negative relationship between calf adiposity and fat tissue accumulated around the waist and the BMI (in some groups). This suggests that participants with greater calf adiposity had lower waist adiposity and BMI than those with less fat tissue on the lower limb. CONCLUSION: Persons with higher calf adiposity may have a lower cardiometabolic risk. This observation is significant because cardiovascular risk factors can persist from childhood into adulthood. Additionally, cardiovascular issues have numerous medical consequences but also socio-economic ones, thus they can affect individuals and be a burden on public health.

Body height, weight, and Body Mass Index - magnitude and pace of secular changes in children and adolescents from Kraków (Poland) between 1983 and 2020.

OBJECTIVE: The aim of this study was to analyze the occurrence and pace of secular trends regarding body height, weight, and Body Mass Index (BMI) among children and adolescents from Kraków (Poland) examined in 1983, 2000, 2010, and 2020. METHODS: The study group consisted of 17 407 individuals (8650 girls and 8757 boys) aged 3-18 included in four cross-sectional studies conducted in 1983, 2000, 2010, and 2020.Analyzed anthropometric characteristics included body height (measured according to Martin's technique, with an anthropometer) and body weight. BMI was calculated as follows: body weight (kg)/body height2 (m). RESULTS: Results of the current study suggest that there was a cessation of previously observed secular increase of the body height in the examined population in the recent decade. Additionally, secular changes regarding body height, body mass, and BMI occurred noticeably slower in the recent decade compared to the previous years. CONCLUSIONS: In conclusion, the rapid increase of body height in the years 1983-2000 and later secular increase of the body mass and BMI in 2000-2010 were probably associated mainly with significant socio-economic progress of the country. On the other hand, deceleration of those trends in 2010-2020, especially in regards to body height, may be associated with reaching the maximum genetically attainable body height in the examined population.

Secular changes in the waist, hips circumferences and selected associated indicators, among preschool children from Kraków (Poland), between 1983 and 2018.

OBJECTIVES: Waist circumference and derived indicators are great for measuring the risk of abdominal obesity. The main aim of the study was to assess the changes in the waist, hips circumferences and selected associated indicators, among preschool children (3-7 years of age) from Kraków, Poland, between 1983, 2008 and 2018. METHODS: The research was conducted in randomly selected kindergarten in Krakow (Poland). The 1983 cohort consisted of 1414 children and the 2008 and 2018 series included 1050 preschoolers each. Analyzed characteristics included waist and hip circumferences, body height, waist-to-hips ratio (WHR) and waist-to-height ratio (WHtR). RESULTS: There was a negative secular trend regarding circumferences of the hips and waist, as well as WHtR. In girls, WHR was, the greatest in the 2018 cohort, while among boys there was a secular increase in the value of this parameter compared to the 2008 cohort, but not to the 1983 series. CONCLUSIONS: The coexistence of currently noted trends with the previously described secular decrease in the prevalence of overweight/obesity and increase in trunk adiposity in the same population, suggests that WHR is preferable to body mass index in assessing the risk associated with excess adiposity in the population examined in the presented study.

Changes in adiposity and fat tissue distribution among preschool children from Kraków, Poland, from 2008 to 2018.

In the light of changes in the living conditions of populations, excess adiposity is currently a serious public health problem worldwide. The aim of this study was to assess the changes in the body fat ratio among preschool children aged 3-7 years from Kraków, Poland, between 2008 and 2018. The study group consisted of children examined in two cross-sectional studies. Analysed characteristics included triceps, calf, subscapular, abdominal and suprailiac skinfold thicknesses, and adiposity calculated according to Slaughter's equations. The trunk adiposity index and limbs-to-trunk fat ratio were also calculated. Statistical significance was obtained using two-way ANOVA and Tukey's tests. Lower-limb adiposity was largest in the 2008 cohort and trunk adiposity was greater in the 2018 cohort. The mean values of the trunk adiposity index and limbs-to-trunk fat ratio were lower in the 2018 cohort than in the 2008 cohort. The 2018 cohort was also characterized by a lower overall adiposity. Regardless of the lower body adiposity percentage, in 2018 there was a tendency towards the central allocation of fat tissue. This is a negative phenomenon because, especially when co-existing with reduced lower-limb adiposity, it is associated with an increased risk of metabolic and cardiovascular diseases, even in young children.

The impact of lifestyle and socioeconomic parameters on body fat level in early childhood.

The aim of this study was to examine the differences between selected lifestyle and socioeconomic parameters among preschool (3-7 years of age) children of differing adiposity status. The study was conducted from February to June 2018 in 20 randomly selected kindergartens in Kraków, Poland. Triceps, biceps, subscapular, suprailiac, abdominal and calf skinfold thicknesses were measured. The sum of all six skinfolds was calculated and the children were subsequently characterized by low (≤-1 SD [standard deviation]), normal (-1 to 1 SD) or high body fat (≥1 SD). Socioeconomic and lifestyle characteristics were obtained using a questionnaire filled out by the children's parents or legal guardians. Preschool children in the high adiposity category had, on average, fewer siblings and longer screen time; additionally, their parents had lower education and more often worked in manual jobs, in comparison to the children in the low and average adiposity categories. In conclusion, it was observed that children in different adiposity categories varied in terms of some socioeconomic as well as lifestyle characteristics. Knowledge regarding the influence that those factors can have on the metabolic health of children is essential for children's present as well as future well-being. Moreover, it can help health care professionals and parents decide what intervention and/ or preventive measures should be undertaken to ensure the best possible outcomes, as the development of successful obesity prevention strategies should rely on evidence-based information. Nonetheless, future research examining the issue of factors influencing the metabolic health of children, as well as these outcomes later in life, is crucial. Well-planned studies including a large number of individuals, as well as longitudinal research, will be particularly beneficial in this regard.

Body composition of children with different gestation time.

OBJECTIVES: To examine the differences in body composition between prepubescent children, depending on the time of gestation. METHODS: The study was conducted among children aged 3-10 years. The thickness of 5 (triceps, subscapular, suprailiac, abdominal, calf) skinfolds, mid-upper arm circumference, body height, weight and femur breadth was measured. Sum of 3 skinfolds, Body Mass Index (BMI) and muscle mass were calculated. Gestation time was obtained using a questionnaire. RESULTS: Children in the short gestation time category were generally characterized by the greatest values of the analyzed characteristics, particularly above the ages of 6-8 years. Femur breadth and muscle mass were similar up to the mentioned age in all of the gestation time categories. BMI and all of the adiposity characteristics, below the age of 6 years, were the greatest in the long gestation time category. CONCLUSIONS: Results of the present study are important, as excess body mass and adiposity are associated with increased risk of cardiovascular and metabolic abnormalities later in life. Special emphasis should be placed on the prevention of overweight and obesity among premature babies and the education of their parents.

Skeletal and muscular robustness and physical fitness of Polish children and adolescents (3-18 years) with normal weight and overweight/obesity.

Individuals with excess body mass are usually characterised by a more robust skeleton and greater muscle mass than their leaner counterparts. The aim of this study was to evaluate the skeletal robustness, bone and muscle mass as well as physical fitness of Polish children and adolescents with and without excess body mass. The study group consisted of 3292 individuals (1705 girls and 1587 boys). Body height, mass, triceps skinfold, humerus, femur and bistyloid breadths, as well as thigh and mid-upper arm circumferences, were measured. BMI, Frame Index, bone and muscle mass were calculated. Results of handgrip strength, standing broad jump, sit-and-reach and shuttle-run tests were obtained. Participants were categorised as normal-weight or with overweight/obesity according to Cole's cut-offs. Statistical differences were calculated using two-way ANOVA (independent variables: age category, BMI group; dependent variable: analysed characteristic). Individuals in the overweight/obese category had larger absolute bone and muscle mass, as well as values of associated measurements and results of handgrip strength than their leaner counterparts. The normal-weight individuals had a greater relative bone, muscle mass and achieved better results in most fitness tests, including relative dynamometric force. In conclusion, individuals in the overweight/obese category were characterised by an increased absolute mass of bone and muscle tissue, as well as greater values of associated measurements, in comparison to their leaner counterparts. However, those advantages did not translate into better physical fitness. It may be associated with the fact that in proportion to the total body weight, bone and muscle mass were greater among participants in the normal-weight category.

Social inequalities in obesity and overweight: secular changes in Poland between 1983 and 2020.

BACKGROUND: Human development is strongly influenced by environmental factors, including the socioeconomic status (SES) of the family. The aim of this study is to analyze the prevalence of excess body weight among Polish children and adolescents from families of varying SES examined in 1983 and 2020. METHODS: The study group included 3-15-year olds from two cross-sectional surveys (1983 and 2020) conducted in kindergartens and schools. The 1983 cohort consisted of 3394 individuals and the one from 2020-of 1253 children and adolescents. Body height and weight were measured and body mass index was calculated. Inclusion into underweight, normal weight and overweight/obese categories was based on Cole's cutoff points. SES was established based on the place of the parents' birth, parents', education status and the number of children in the family, which were self-reported in a questionary by the parents of the examined individuals. RESULTS: The mean overall SES was higher in the 2020 cohort, in comparison to the one examined in 1983. This change was also reflected by the changing prevalence of excess body weight, which, in 1983 was the greatest in the high socioeconomic category. On the other hand, in 2020 overweight/obesity was the most prevalent among individuals from families of low SES. CONCLUSIONS: The present results confirm the findings obtained in other countries, which suggest that changing the level of socioeconomic development modifies the changes regarding the prevalence of excess body weight. It is an important observation because a study of this type has not yet been conducted in the Polish population.

Body fat percentage estimation in children - searching for the most accurate equation.

Background and aims: Analysis of body composition is a very important issue, and it is often used as one of the crucial markers of overall health. The aim of the study was to analyse the relationship between the percentage of body fat ratio estimated using selected equations and adiposity obtained by bioimpedance in 7-16-year-olds from Kraków (Poland). Methods and results: The study included 1887 children and adolescents. Body weight and height were measured according to standard methods and Body Mass Index was calculated on the basis of those measurements. Biceps, triceps, subscapular, suprailiac, abdominal and calf skinfolds were measured. Adiposity was obtained using the BIA method as well as estimated by Siri, Goran, Slaughter, Deurenberg, Huang, Dezenberg, Ripka and Brozek equations. Relationship between results obtained from the equations and bioimpedance was assessed using Deming regression. All calculations were performed using Microsoft Excel and MedCalc. Statistically significant (p ≤ 0.001) relationship between adiposity obtained by bioimpedance and estimated was observed for all of the analysed equations. For girls, the strongest one was noted for Siri equation, with R = 0.83 (95%CI: 0.81-0.85). Among boys, the strongest relationship was observed for 3-skinfolds based equation developed by Ripka, with the Pearson's correlation coefficient value of 0.84 (95%CI: 0.81-0.85). Conclusions: The most useful equation to estimate the body fat percentage in the population of 7-16-year olds from Kraków (Poland) differed between the sexes. For boys, it was Ripka 3-skinfold equation, while for girls it was the equation developed by Siri.