Body composition of elite class distance runners

Association between patellar tendon moment arm and running performance in endurance runners

A shorter joint moment arm (MA) may help maintain the necessary muscle force when muscle contractions are repeated. This beneficial effect may contribute to reducing the energy cost during running. In this study, we examined the correlation between patellar tendon MA and running performance in endurance runners. The patellar tendon MA and quadriceps femoris muscle volume (MV) in 42 male endurance runners and 14 body size-matched male untrained participants were measured using a 1.5-T magnetic resonance system. The patellar tendon MA was significantly shorter in endurance runners than in untrained participants (p = 0.034, d = 0.65). In endurance runners, shorter patellar tendon MA correlated significantly with better personal best 5000-m race rime (r = 0.322, p = 0.034). A trend toward such a significant correlation was obtained between quadriceps femoris MV and personal best 5000-m race time (r = 0.303, p = 0.051). Although the correlation between patellar tendon MA and personal best 5000-m race time did not remain significant after adjusting for the quadriceps femoris MV (partial r = 0.247, p = 0.120), a stepwise multiple regression analysis (conducted with body height, body mass, patellar tendon MA, and quadriceps femoris MV) selected the patellar tendon MA (β = 0.322) as only a predictive variable for the personal best 5000-m race time (adjusted R2  = 0.081, p = 0.038). These findings suggest that the shorter patellar tendon MA, partially accorded with the smaller quadriceps femoris size, may be a favorable morphological variable for better running performance in endurance runners.

Body Composition and Bone Mineral Density of Division 1 Collegiate Track and Field Athletes, a Consortium of College Athlete Research (C-CAR) Study

The purpose of the present study was to generate normative values for total and regional body composition in male and female Division 1 collegiate track and field athletes using dual X-ray absorptiometry. We also sought to examine body composition by event and sex. Data were used from the Consortium of College Athlete Research group. A total of 590 (male [M]/female [F] = 274/316) athletes had their height, weight, total and regional fat mass (FM), lean mass, and bone mineral density (BMD) measured. Athletes were classified into 1 of 7 categories: Jumps (M/F = 28/30); Long Distance (M/F = 104/110), Middle Distance (M/F = 27/24), Multievent (M/F = 11/9), Pole Vault (M/F = 21/27), Sprints (M/F = 54/96), and Throws (M/F = 29/20). Total and regional differences between events and sex were assessed by analysis of variance. Except for male and female throwers, all other track and field athletes' mean percent body fat (M: 10.3%-12.6%, F: 17.5%-21.6%) and visceral FM (<500 g) was low, but in a healthy range. As expected, throwers had significantly (p < 0.05) higher total and regional FM and lean mass than other events. In addition, male (1.55 ± 0.11 g/cm²) and female (1.40 ± 0.12 g/cm²) throwers had significantly greater BMD than all other events while male (1.25 ± 0.10 g/cm²) and female (1.16 ± 0.09 g/cm²) distance runners had significantly lower BMD than all other events. In conclusion, track athletes' body composition differed across events for both males and females. These measurements provide normative data on NCAA Division 1 male and female track and field athletes.

Anthropometric Characteristics, Body Composition and Somatotype of Elite Male Young Runners

The purpose of the present study was to describe the anthropometric characteristics, body composition and somatotype of elite male young runners (EYR), and to compare these variables according to the specialty in which they engaged (middle-distance vs. long-distance). This will enable an anthropometric profile chart to be established for them. Ninety EYR aged 17 to 23 years (18.4 ± 2.0) participated in the study. Athletes were divided into two groups according to the event in which they participated: middle-distance runners (MDR, n = 56) and long-distance runners (LDR, n = 34). Sixteen anthropometric variables were recorded for each participant: Weight, height, eight skinfolds, four girths, and two breadths. Body mass index (BMI), body composition and somatotype were calculated. Comparing MDR with the group of LDR, significant differences were found to exist for height, weight, relaxed upper arm girth, flexed and tensed upper arm girth, total upper arm area, upper arm muscle area, and thigh muscle area. No significant differences were observed in the other variables. MDR are taller, heavier and have larger girths than LDR. Coaches and sports scientists can use the data obtained to better control training, as well as for talent identification and athlete selection.

Efficacy of thigh volume ratios assessed via stereovision body imaging as a predictor of visceral adipose tissue measured by magnetic resonance imaging

OBJECTIVES

The research examined the efficacy of regional volumes of thigh ratios assessed by stereovision body imaging (SBI) as a predictor of visceral adipose tissue measured by magnetic resonance imaging (MRI). Body measurements obtained via SBI also were utilized to explore disparities of body size and shape in men and women.

METHOD

One hundred twenty-one participants were measured for total/regional body volumes and ratios via SBI and abdominal subcutaneous and visceral adipose tissue areas by MRI.

RESULTS

Thigh to torso and thigh to abdomen-hip volume ratios were the most reliable parameters to predict the accumulation of visceral adipose tissue depots compared to other body measurements. Thigh volume in relation to torso [odds ratios (OR) 0.44] and abdomen-hip (OR 0.41) volumes were negatively associated with increased risks of greater visceral adipose tissue depots, even after controlling for age, gender, and body mass index (BMI). Irrespective of BMI classification, men exhibited greater total body (80.95L vs. 72.41L), torso (39.26L vs. 34.13L), and abdomen-hip (29.01L vs. 25.85L) volumes than women. Women had higher thigh volumes (4.93L vs. 3.99L) and lower-body volume ratios [thigh to total body (0.07 vs. 0.05), thigh to torso (0.15 vs. 0.11), and thigh to abdomen-hip (0.20 vs. 0.15); P < 0.05].

CONCLUSIONS

The unique parameters of the volumes of thigh in relation to torso and abdomen-hip, by SBI were highly effective in predicting visceral adipose tissue deposition. The SBI provided an efficient method for determining body size and shape in men and women via total and regional body volumes and ratios. Am. J. Hum. Biol. 27:445-457, 2015. © 2015 Wiley Periodicals, Inc.

Nutrition concepts for elite distance runners based on macronutrient and energy expenditure

CONTEXT

Elite distance runners (EDR) must optimize their nutrition to maintain their demanding training schedules.

OBJECTIVE

To develop a nutrition concept for EDR based on energy and macronutrient expenditures.

DESIGN

This theoretical study provides calculations for macronutrient and energy expenditures of EDR. Anthropometric and metabolic characteristics of EDR were assumed based on average real EDR.

SETTING

University of Kiel.

PATIENTS OR OTHER PARTICIPANTS

Three prototypic types of male EDR described in the literature as type I (TI; body mass = 72 kg, respiratory quotient = 0.9 at rest, fast-twitch muscle fibers = 60% to 70%), type II (TII; body mass = 67 kg, respiratory quotient = 0.82 at rest, fast-twitch muscle fibers = 50%), and type III (TIII; body mass = 60 kg, respiratory quotient = 0.75 at rest, fast-twitch muscle fibers = 30% to 40%).

MAIN OUTCOME MEASURE(S)

We calculated the macronutrient and energy expenditures of the 3 types of EDR according to body mass, respiratory quotient, and percentage of fast-twitch muscle fibers.

RESULTS

We found that the average energy expenditure was 3750 kcal . d(-1) for TI runners, 3463 kcal . d(-1) for TII runners, and 3079 kcal . d(-1) for TIII runners. The carbohydrate (CHO) expenditure reached an average value of 10.0 g . kg(-1) . d(-1) for TI runners, 8.0 g . kg(-1) . d(-1) for TII runners, and 4.7 g . kg(-1) . d(-1) for TIII runners. When the EDR accomplished running sessions at a pace >or=100% of maximum oxygen consumption, all types of runners had a CHO demand of about 10 g . kg(-1) . d(-1). The TI and TII runners need a CHO intake of 8 to 10 g . kg(-1) . d(-1). For the TIII runners, a CHO intake >6 g . kg(-1) . d(-1) is necessary during anaerobic training sessions.

CONCLUSIONS

Nutrition concepts must be differentiated for EDR according to metabolic and anthropometric characteristics of the runners and their special training emphases.

Skinfold thicknesses associated with distance running performance in highly trained runners

It has been postulated that additional adiposity has a negative effect on performance in heterogeneous groups of runners. Previous studies have not tested this hypothesis in homogeneous groups of elite runners. The purpose of this study was to determine whether the sum of skinfold thicknesses and specific single skinfold sites were related to competitive running performance in homogeneous groups of male and female elite athletes. In total, 184 top-class runners (130 males and 54 females) volunteered to participate in the study. Skinfolds were measured at the following sites: biceps, triceps, subscapular, pectoral, iliac crest, abdominal, front thigh and medial calf. Runners were classified into groups in accordance with their best performance times. Correlation analysis and partial correlation coefficients that controlled for age and weight were applied to each single skinfold, the sum of six skinfolds (excluding biceps) and the extremity (sum of triceps, front thigh, medial calf) to trunk (sum of subscapular, iliac crest, abdominal) ratio and performance. Performance was rated by the scoring procedures of the International Amateur Athletics Federation. In male runners, the pectoral, iliac crest, abdominal, biceps, triceps, subscapular skinfolds and the sum of six skinfolds were not associated with performance score for any of the distances. High correlations were found between the front thigh (r = 0.78, P = 0.000) and medial calf (r = 0.55, P = 0.018) skinfolds and 1500 m run time, and between the front thigh (r = 0.59, P = 0.014) and medial calf (r = 0.57, P = 0.017) skinfolds and 10,000 m run time. In female runners, the front thigh and medial calf skinfolds were highly correlated with 400 m run time (r = 0.71, P = 0.022 and r = 0.81, P = 0.005, respectively). The results of this study indicate that skinfold thicknesses in the lower limb are positively associated with running time over several distances, and may be a useful predictor of athletic performance.

Artificial selection for high activity favors mighty mini-muscles in house mice

After 14 generations of selection for voluntary wheel running, mice from the four replicate selected lines ran, on average, twice as many revolutions per day as those from the four unselected control lines. To examine whether the selected lines followed distinct strategies in the correlated responses of the size and metabolic capacities of the hindlimb muscles, we examined mice from selected lines, housed for 8 wk in cages with access to running wheels that were either free to rotate ("wheel access" group) or locked ("sedentary"). Thirteen of twenty individuals in one selected line (line 6) and two of twenty in another (line 3) showed a marked reduction ( approximately 50%) in total hindlimb muscle mass, consistent with the previously described expression of a small-muscle phenotype. Individuals with these "mini-muscles" were not significantly smaller in total body mass compared with line-mates with normal-sized muscles. Access to free wheels did not affect the relative mass of the mini-muscles, but did result in typical mammalian training effects for mitochondrial enzyme activities. Individuals with mini-muscles showed a higher mass-specific muscle aerobic capacity as revealed by the maximal in vitro rates of citrate synthase and cytochrome c oxidase. Moreover, these mice showed the highest activities of hexokinase and carnitine palmitoyl transferase. Females with mini-muscles showed the highest levels of phosphofructokinase, and males with mini-muscles the highest levels of pyruvate dehydrogenase. As shown by total muscle enzyme contents, the increase in mass-specific aerobic capacity almost completely compensated for the reduction caused by the "loss" of muscle mass. Moreover, the mini-muscle mice exhibited the lowest contents of lactate dehydrogenase and glycogen phosphorylase. Interestingly, metabolic capacities of mini-muscled mice resemble those of muscles after endurance training. Overall, our results demonstrate that during selection for voluntary wheel running, distinct adaptive paths that differentially exploit the genetic variation in morphological and physiological traits have been followed.

Evolution of a small-muscle polymorphism in lines of house mice selected for high activity levels

To study the correlated evolution of locomotor behavior and exercise physiology, we conducted an artificial selection experiment. From the outbred Hsd:ICR strain of Mus domesticus, we began eight separate lines, each consisting of 10 breeding pairs. In four of the lines, we used within-family selection to increase voluntary wheel running. The remaining four lines were random-bred (within lines) to serve as controls. Various traits have been monitored to test for correlated responses. Here, we report on organ masses, with emphasis on the triceps surae muscle complex, an important extensor of the ankle. Mice from the selected lines exhibit reduced total body mass, increased relative (mass-corrected) kidney mass, and reduced relative triceps surae mass. In addition, a discrete muscle-mass polymorphism was observed: some individuals had triceps surae that were almost 50% lighter than normal for their body mass. This small-muscle phenotype was observed in only three of the eight lines: in one control line, it has fluctuated in frequency between zero and 10%, whereas in two of the selected lines it has increased in frequency to approximately 50% by generation 22. Data from a set of parents and offspring (generations 23 and 24) are consistent with inheritance as a single autosomal recessive allele. Evidence for the adaptive significance of the small-muscle allele was obtained by fitting multiple-generation data to hierarchical models that include effects of genetic drift and/or selection. The small-muscle allele is estimated to have been present at low frequency (approximately 7%) in the base population, and analysis indicates that strong selection favors the allele in the selected but not control lines. We hypothesize that the small muscles possess functional characteristics and/or that the underlying allele causes pleiotropic effects (e.g., reduced total body mass; increased relative heart, liver, and kidney mass) that facilitate high levels of wheel running. Nevertheless, at generation 22, wheel running of affected individuals did not differ significantly from those with normal-sized muscles, and the magnitude of response to selection has been similar in all four selected lines, indicating that multiple genetic "solutions" are possible in response to selection for high activity levels.

Body composition measurement: a hierarchy of methods

The range of methods now available to estimate body composition is extensive. In most cases there is a relationship between cost, complexity and information content. The consequence is that choices can still be made depending on the finances available and the needs of the health professional. This paper reviews four methods ranging in availability and clinical detail. The alternatives are use of skinfolds, electrical impedance, underwater weighing and dual energy X-ray absorptiometry. These should provide the practitioner with viable options to consider in the assessment of body composition. Although no method has been designed specifically for children, reference is made throughout to studies on paediatric subjects of the major issues involved in these methods, which will assist paediatric endocrinologists in making informed decisions.

Body composition measurement: a review of hydrodensitometry, anthropometry, and impedance methods

Human body composition is an expression of genetic and nutritional factors. It can change as a consequence of exogenous influences such as training, disease, or diet and is therefore of particular interest to nutrition professionals. Two of the main methods of estimating body composition in this review (hydrodensitometry and anthropometry) have been in use for decades, but the third method (bioelectrical impedance) is more recent. The procedure, theoretical basis, assumptions, standard error of estimates, and comparisons with other techniques are presented for each of the three methods. References to general and specific populations are presented that illustrate regression equations for different ages, ethnic groups, and gender. The advantages and disadvantages of the three methods are reviewed with reference made to the alternative compartment models. Other methods (DEXA, infrared interactance) are briefly reviewed.

Twenty-year follow-up of aerobic power and body composition of older track athletes

The purpose was to determine the aerobic power (maximal oxygen uptake) and body composition of older track athletes after a 20-yr follow-up (T3). At 20 yr, 21 subjects [mean ages: 50.5 +/- 8.5 yr at initial evaluation (T1), 60.2 +/- 8.8 yr at 10-yr follow-up (T2), and 70.4 +/- 8.8 yr at 20-yr follow-up (T3)] were divided into three intensity groups: high (H; remained elite; n = 9); moderate (M; continued frequent moderate-to-rigorous endurance training; n = 10); and low (L; greatly reduced training; n = 2). All groups decreased in maximal oxygen uptake at each testing point (H, 8 and 15%; M, 13 and 14%; and L, 18 and 34% from T1 to T2 and T2 to T3, respectively). Maximal heart rate showed a linear decrease of approximately 5-7 beats.min-1.decade-1 and was independent of training status. Body weight remained stable for the H and M groups and percent fat increased approximately 2-2.5%/decade. Although fat-free weight decreased at each testing point, there was a trend for those who began weight-training exercise to better maintain it. Cross-sectional analysis at T3 showed that leg strength and bone mineral density were generally maintained from age 60 to 89 yr. Those who performed weight training had a greater arm region bone mineral density than those who did not. These longitudinal data show that the physiological capacities of older athletes are reduced despite continued vigorous endurance exercise over a 20-yr period (approximately 8-15%/decade). Changes in body composition appeared to be less than those shown for the healthy sedentary population and were related to changes in training habits.

Biomechanics and running economy

Running economy, which has traditionally been measured as the oxygen cost of running at a given velocity, has been accepted as the physiological criterion for 'efficient' performance and has been identified as a critical element of overall distance running performance. There is an intuitive link between running mechanics and energy cost of running, but research to date has not established a clear mechanical profile of an economic runner. It appears that through training, individuals are able to integrate and accommodate their own unique combination of dimensions and mechanical characteristics so that they arrive at a running motion which is most economical for them. Information in the literature suggests that biomechanical factors are likely to contribute to better economy in any runner. A variety of anthropometric dimensions could influence biomechanical effectiveness. These include: average or slightly smaller than average height for men and slightly greater than average height for women; high ponderal index and ectomorphic or ectomesomorphic physique; low percentage body fat; leg morphology which distributes mass closer to the hip joint; narrow pelvis and smaller than average feet. Gait patterns, kinematics and the kinetics of running may also be related to running economy. These factors include: stride length which is freely chosen over considerable running time; low vertical oscillation of body centre of mass; more acute knee angle during swing; less range of motion but greater angular velocity of plantar flexion during toe-off; arm motion of smaller amplitude; low peak ground reaction forces; faster rotation of shoulders in the transverse plane; greater angular excursion of the hips and shoulders about the polar axis in the transverse plane; and effective exploitation of stored elastic energy. Other factors which may improve running economy are: lightweight but well-cushioned shoes; more comprehensive training history; and the running surface of intermediate compliance. At the developmental level, this information might be useful in identifying athletes with favourable characteristics for economical distance running. At higher levels of competition, it is likely that 'natural selection' tends to eliminate athletes who failed to either inherit or develop characteristics which favour economy.

Applied physiology of water-skiing

Water-skiing is a physically demanding sport involving highly coordinated movements, extreme upper body torques, sustained isometric contractions and near maximal stresses on the anaerobic system. Due to the physical demands of the sport, elite skiers have developed physiological characteristics similar to other elite athletes. However, until recently little research has focused on the kinesiology, physiology and physical conditioning of water-skiing.

The estimation of body density in rugby union football players

The general regression equation of Durnin and Womersley for estimating body density from skinfold thicknesses in young men, was examined by comparing the estimated density from this equation, with the measured density of a group of 45 rugby union players of similar age. Body density was measured by hydrostatic weighing with simultaneous measurement of residual volume. Additional measurements included stature, body mass and skinfold thicknesses at the biceps, triceps, subscapular and suprailiac sites. The estimated density was significantly different from the measured density (P < 0.001), equivalent to a mean overestimation of relative fat of approximately 4%. A new set of prediction equations for estimating density was formulated from linear regression using the logarithm of single and sums of skinfold thicknesses. Equations were derived from a validation sample (n = 22) and tested on a crossvalidation sample (n = 23). The standard error of the estimate (s.e.e.) of the equations ranged from 0.0058 to 0.0062 g ml-1. The derived equations were successfully crossvalidated. Differences between measured and estimated densities were not significant (P > 0.05), total errors ranging from 0.0067 to 0.0092 g ml-1. An exploratory assessment was also made of the effect of fatness and aerobic fitness on the prediction equations. The equations should be applied to players of similar age and playing ability, and for the purpose of identifying group characteristics. Application of the equations to individuals may give rise to errors of between -3.9% to +2.5% total body fat in two-thirds of cases.

Anthropometric profiles of elite male and female competitive sport rock climbers

Over the past few years, competitive rock climbing--for a long time a popular sport in Europe--has increased in popularity in North America. An annual international World Cup competition circuit was started in 1988 which has shown growing success and a definite elite group of athletes has emerged. Descriptive anthropometric profiles of elite climbers have been unavailable. In order to fill this information void, 39 world-class climbers (21 males, 18 females) were assessed immediately prior to competition at an international World Cup sport climbing championship. All of the subjects tested were competition semi-finalists and, among these, seven males and six females advanced to the finals. The variables measured included age, years of climbing experience, height, body mass, height-weight ratio, sum of seven skinfolds, % body fat, fat-free mass, hand and arm volumes via plethysmography, average of right and left grip strengths, grip strength to body mass ratio (SMR), and climbing ability defined as the most difficult route climbed on lead. The results indicated that elite sport climbers are of small to moderate stature and exhibit very low % fat, moderate grip strength and high SMR when compared with other athletic groups. Values for the height-weight ratio and sum of seven skinfolds in the female finalists were very near those of the male finalists, which may indicate that reduction of body mass and % fat are primary adaptations in these female athletes. Climbing ability was predictable from SMR and % fat, though the R2 was low.

Effects of exercise on energy balance in meal-fed mice

The effects of exercise on energy balance have been investigated in mice accustomed to eating their daily food ration in three meals. A meal period lasts 1 hour, and during that period mice were allowed to eat unrestrictedly a pelleted stock diet. Two series of experiments were conducted. In one series of experiments indirect calorimetric measurements were carried out in untrained mice that were assigned to 3 experimental groups; a first group of mice was allowed to rest; a second group of mice was exercised immediately before one of the 3 meals; a third group of mice was exercised immediately after one of the 3 meals. The exercise bout consisted of 1 hour of forced exercise on a rodent treadmill at a speed of 20 meters per minute. O2 consumption (VO2) and CO2 production were monitored throughout a full day except at the time the exercising animals were on the treadmill. In a second series of experiments long-term energy balance measurements were carried out. Mice were then assigned to experimental conditions similar to those previously described for 31 days during which period food intake and body weight were continuously monitored. At the end of 31 days of experiment, mice were killed, and their carcasses were individually analysed for their contents of energy, fat and protein. Carcass and food gross energy contents were assessed by bomb calorimetry. At the end of the long-term energy balance trial, the percentage of fat, the energy gain, the energy density and the weight of the dry carcass were significantly lower in exercised groups of mice than in the resting group of animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Physiological differences between black and white runners during a treadmill marathon

To determine why black distance runners currently out-perform white distance runners in South Africa, we measured maximum oxygen consumption (VO2max), maximum workload during a VO2max test (Lmax), ventilation threshold (VThr), running economy, inspiratory ventilation (VI), tidal volume (VT), breathing frequency (f) and respiratory exchange ratio (RER) in sub-elite black and white runners matched for best standard 42.2 km marathon times. During maximal treadmill testing, the black runners achieved a significantly lower (P less than 0.05) Lmax (17 km h-1, 2% grade, vs 17 km h-1, 4% grade) and VI max (6.21 vs 6.82 l kg-2/3 min-1), which was the result of a lower VT (101 vs 119 ml kg-2/3 breath-1) as fmax was the same in both groups. The lower VT in the black runners was probably due to their smaller body size. The VThr occurred at a higher percentage VO2max in black than in white runners (82.7%, SD 7.7% vs 75.6%, SD 6.2% respectively) but there were no differences in the VO2max. However, during a 42.2-km marathon run on a treadmill, the black athletes ran at the higher percentage VO2max (76%, SD 7.9% vs 68%, SD 5.3%), RER (0.96, SD 0.07 vs 0.91, SD 0.04) and f (56 breaths min-1, SD 11 vs 47 breaths min-1, SD 10), and at lower VT (78 ml kg-2/3 breath-1, SD 15 vs 85 ml kg-2/3 breath-1, SD 19). The combination of higher f and lower VT resulted in an identical VI.(ABSTRACT TRUNCATED AT 250 WORDS)

Anthropometric and training variables related to 10km running performance

Sixty male distance athletes were divided into three equal groups according to their personal best time for the 10km run. The runners were measured anthropometrically and each runner completed a detailed questionnaire on his athletic status, training programme and performance. The runners in this study had similar anthropometric and training profiles to other distance runners of a similar standard. The most able runners were shorter and lighter than those in the other two groups and significantly smaller skinfold values (P less than 0.05). There were no significant differences between the groups for either bone widths or circumferences but the elite and good runners had significantly higher ponderal indices (P less than 0.05) than the average runners, indicating that they are more linear. Elite and good runners were also less endomorphic but more ectomorphic than the average runners. The elite runners trained more often, ran more miles per week and had been running longer (P less than 0.05) than good or average runners. A multiple regression and discriminant function analysis indicated that linearity, total skinfold, the type and frequency of training and the number of years running were the best predictors of running performance and success at the 10km distance.

Australian Rules football: an anthropometric study of participants

Anthropometric measurements and personal data were collected from 119 Australian Rules footballers from Victoria. A top level professional league team, a second level association team, and an A-grade amateur association team were observed, representing three levels of ability. The profile of physical features of these athletes at the beginning of the season is presented. A gradation of body size was observed between teams. The players in the top level team were slightly taller and heavier than those in the other teams. They had less body fat, as shown by lesser skinfold thicknesses, a smaller percentage body fat as determined by prediction equations, and a greater fat-free mass. The intermediate level team showed an intermediate level of body fat and the lower level team had the highest proportion of fat.

The estimation of body density in men: are general equations general?

Regression equations for estimating body density and fatness from anthropometric measurements are usually specific to the populations from which they are derived, owing to methodological and biological factors. Some equations are, however, regarded as having general validity for subjects of different ages, levels of fatness and fitness. In this study, five such general equations were tested by comparing estimated body density (Dest) with measured body density (Dmeas) in 138 European men employed in an Italian shipyard. Body density was measured by underwater weighing with the simultaneous determination of lung residual volume. Measurements were also made of height, weight, eight skinfolds, four circumferences and seven diameters by standard techniques. Dest from the five general equations were significantly different from Dmeas (P less than 0.001). New prediction equations for estimating D were drawn up by simple and multiple regression of various combinations of skinfolds expressed as individual skinfolds, sums, log sums and the quadratic form. Equations were drawn up on a validation sample (N = 92) and tested on a cross-validation sample (N = 46). The form of skinfolds and the combination selected made little difference to the SEEs and R2 but the inclusion of age resulted in lower SEEs. Stepwise multiple regression produced an equation incorporating thorax and triceps skinfolds and age with an SEE of 6 kg/m3 and R2 of 79%. The derived equations were successfully cross-validated, Dmeas and Dest were not significantly different, ryy' and SEE were similar to those of the validation sample. When the cross-validation sample was divided into two according to age, density or VO2 max, the derived equations were applicable to the upper and lower groups for age or physical fitness but not to the groups differing in fatness. These equations should be validated further on other samples by studies performed with due regard to the methodological factors, both technical and statistical, that may result in specificity. However, the poor performance of the general equations tested and the specificity for fatness of the derived equations suggest that biological factors may preclude the development of general prediction equations for body density.

1980 Melbourne marathon study

Most of the 5423 entrants in the Melbourne 1980 Big M Marathon were non-elite athletes. A study of a stratified random sample of 459 entrants (which represented a 42% response rate) found that, while entrants reflected the community standards of disease, they pursued healthier lifestyles. Preparation for the marathon led to a number of positive changes in the health standard of runners. The principal negative consequence of marathon training was the high rate of musculoskeletal problems (30%). Before the race, only 4% of participants had an adequate fluid intake; 33% had pre-existing problems, mainly involving muscles and joints (63%) and viral or gastrointestinal illnesses (41%). These entrants had a 60% less chance of finishing the race. Symptoms during the race were reported by 92% of entrants, but most of these were not serious; only 6% of entrants were unable to finish the race. The pattern of symptoms after the race was similar to that during the race; 50% of these resolved within three hours. Ninety-seven entrants (2%) required medical attention during the race. Serious problems were rare (only in three entrants), and no runner required admission to hospital for longer than 24 hours. Entrants were at greater risk of requiring medical attention or experiencing problems during and after the race if they had a shorter preparation (less than two months), ran fewer kilometres per week (less than 60 km/week) in the last two or three months before the race, and had performed fewer long training runs (more than 24 km).

Physical characteristics of novice and experienced women marathon runners

The physiological and anthropometric characteristics of 23 non-elite women marathoners were studied. Ten of these women had never run a marathon before (novices) and 13 had run at least one marathon during the previous year (experienced). A comparison of characteristics of these two groups to each other and to elite women marathoners, as reported in the literature, disclosed no significant (p greater than 0.01) among the groups in age, % body fat, body weight, height, lean body mass or HR max. Significant differences (p less than 0.01) were noted, however, in VO2 max (45.8, 51.8, 59.1 ml.kg-1 min-1), VE max (76.3, 94.7, 108.9 L.min-1), and years of training (0.54, 2.06, 4.55 years) with the novice runners having the smallest values, the experienced runners having the next larger values, and the elite runners having the largest values. For our subjects, estimated percentage of body fat did not correlate with finish time, but VO2 max and finish time were significantly related (r = -0.72, p less than 0.01). This suggest that women marathon runners are similar in anthropometric measurements, and that improved performance is associated with higher aerobic capacity and years of training rather than with body dimensions.

Physiological and psychological correlates of success in track and field athletes

Twenty-four collegiate distance runners and 20 power athletes (sprinters and jumpers) of various success levels were tested on a number of physiological and psychological parameters. Multiple regression analysis indicated that physiological factors could explain over 81% of the variance related to successful distance running while physiological and psychological factors could explain over 80% of the of the variance related to successful sprinting and jumping. Body weight, fibre type, low density lipoprotein-cholesterol, and hamstring strength were significant singular correlates to successful distance running. Year in school, percent body fat, quadriceps strength, and leg muscle balance were significant single correlates to successful sprinting and jumping performance.

Comparative analysis of physiologic responses to three different maximal graded exercise test protocols in healthy women

The purpose of this study was to compare the three most commonly used maximal graded exercise test (GXT) protocols in healthy women. Submaximal and maximal metabolic and hemodynamic responses were determined from two treadmill protocols, Bruce and Balke, and a bicycle protocol, in 49 women. Maximum oxygen uptake (VO2 max) was significantly different among protocols (Bruce=40.3, Balke=38.4, and Bike=36.6 ml/kg . min -1). Maximum heart rate (HR max) was significantly lower during Bike (178 beats/min) than during Bruce (182) and Balke (183) protocols. No differences in rate of increase in HR or systolic blood pressure (BP) per increase in multiples of the rest metabolic (METs) were found between Bruce and Balke protocols. The rate of recovery of HR and systolic BP was not different among tests. Comparisons of active and sedentary groups showed differences in VO2 max and submaximal HR and recovery HR at common minutes; however, the rate of increase in HR and systolic BP during exercise and the rate of decrease during recovery were not significantly different. Prediction of VO2 max with Bruce and Balke protocols from treadmill time was r=0.91 (SEE +/- 2.7 ml/kg . min -1) and r=0.94 (SEE 2.2 ml/kg . min -1), respectively. These data suggest a difference between men and women in increased HR and systolic BP per METs increase in exertion.

Skinfold Estimates of Body Fat in Major League Baseball Players

In brief: One hundred and thirty-seven major league baseball players and 32 coaches were tested for body composition, and comparisons were made among positions and among teams. Shortstops were the leanest players (9.2% fat), outfielders averaged 9.9%, and pitchers were the fattest (14.7% fat). The players' body composition reflected the movement patterns and defensive requirements of their positions. There were few differences among teams, and in general, the baseball players were comparable to other professional athletes.

Characteristics of National-Class Race Walkers

In brief: Physiological and selected Psychological characteristics of nine highly trained race walkers were studied and the results compared to those for distance runners and other athletes of similar age. The percent body fat of the race walkers was similar to or lower than the other athletes. Their VO2 max of 62.9 ml· kg(-1)· min(-1) was significantly higher than active men of comparable age and similar to or higher than many athletes, but significantly lower than world-class endurance athletes.

Physiological characteristics of young well-trained swimmers

The purpose of this study was to describe body composition, muscular strength, pulmonary function, and aerobic capacity of young swimmers, after 6 years of training. Twelve male members of a competitive swim team, ranging in age for 13 to 16 years, served as subjects. Each subject was measured on 2 separate days at approximately the same time of day on each occasion. On day one, body composition, muscular strength, TLC, FVC, FEV1.0, FRC, RV, and resting DLc0 were determined. On day 2, height, weight, VE max Hr max, and VO2 max were measured. Results indicated that children who train to swim competitively: (1) are lower than average in percent body fat (10.8%) as determined by hydrostatic weighing, (2) are muscularly fit as indicated by the Oregon Cable-Tension Strength Test, and (3) have cardiorespiratory capacities which are greater than one would expect to see in untrained youth of similar ages.

World-Record Rope Skipping Performance

The authors studied a world-champion rope skipper to see what characteristics contribute to his superior performance and to compare him with other world-class athletes.

Generalized equations for predicting body density of men

1. Skinfold thickness, body circumferences and body density were measured in samples of 308 and ninety-five adult men ranging in age from 18 to 61 years. 2. Using the sample of 308 men, multiple regression equations were calculated to estimate body density using either the quadratic or log form of the sum of skinfolds, in combination with age, waist and forearm circumference. 3. The multiple correlations for the equations exceeded 0.90 with standard errors of approximately +/- 0.0073 g/ml. 4. The regression equations were cross validated on the second sample of ninety-five men. The correlations between predicted and laboratory-determined body density exceeded 0.90 with standard errors of approximately 0.0077 g/ml. 5. The regression equations were shown to be valid for adult men varying in age and fatness.