Growth and development of male gymnasts,swimmers, soccer and tennis players: A longitudinal study

Élite adult athletes are known to have physical and physiological characteristics specifically suited to their sport. However, it is not clear whether the observed adult differences arise because of training or whether the sport selects the individual with the appropriate characteristics. The purpose of this prospective study was to compare and contrast the physical development of young athletes (8–19 years), and in so doing provide a possible response to this question. Development of anthropometric characteristics and sexual maturation were assessed in a group of 232 male athletes for three consecutive years. Parental heights were used to predict target heights. The subjects were a randomly selected group of young British athletes, from four sports: soccer, gymnastics, swimming and tennis. Using a linked longitudinal cohort study design (age cohorts 8, 10, 12, 14 and 16 years) it was possible to estimate a consecutive 11-year development pattern, over the 3-year testing period. The adjusted mean (ANCOVA) height, accounting for age and pubertal status, of male swimmers (161·6 ± 0·6 cm) was found to be significantly greater (p < 0·01) than gymnasts (150·7 ± 0·8 cm) and soccer players (158·7 ± 0·6 cm), and their adjusted mean body mass (51·3 ± 0·6 kg) significantly greater (p < 0·01) than the other groups. When testicular volumes were compared, it was found that swimmers had significantly larger volumes than gymnasts and tennis players from 14 to 16 years of age (p < 0·05). Gymnasts' growth curve of testis size was characteristic of late maturers, the swimmers' curve was characteristic of early maturers. As all the young athletes started training prior to puberty the observed late sexual maturation of gymnasts and early maturation of swimmers suggests some form of sports-specific selection. Training did not appear to have affected these young athletes's growth and development; rather their continued success in sport appeared to be related to inherited traits.     

Relationships between muscle strength and muscle cross-sectional area in male sprinters and endurance runners

Summary The relationship between the cross-sectional area (CSA) and maximum voluntary isometric strength of the knee extensor muscles was measured in a group of untrained subjects (control group, n=30), a group of successful marathon runners (n=6) and a group of successful sprinters (n=6). All subjects were male, aged between 20 and 41 years. In the control group muscle strength was found to be positively correlated with lean body mass (p<0.01) and with muscle CSA as determined by computed tomography scanning of the leg at mid-thigh level (p<0.001). However, in spite of these significant relationships, there was considerable variability between subjects. The sprinters were significantly stronger than the endurance runners (p<0.01), but neither of the athletic groups differed significantly from the control group. Muscle CSA was greater in the sprinters than in the marathon runners but this difference was not significant. The ratio of muscle strength to CSA in the control group varied from 7.07 to 13.57. All the trained subjects fell within this normal range, but the sprinters' muscles were stronger per unit CSA than the muscles of the marathon runners (p<0.05). Since it is well established that the leg muscles of sprinters contain a high proportion of fast twitch (FT) muscle fibres whereas endurance runners have a high proportion of slow twitch (ST) fibres, these results suggest that the strength which can be produced by a muscle may depend on its fibre composition. Variation in the distribution of the different fibre types in the untrained population may therefore account at least in part for the wide variability observed in this group.Supported by a grant from Lipha Pharmaceuticals Ltd     

Functional capacity and body composition in top weight-lifters,swimmers, runners and skiers

Summary Groups of top weight lifters, swimmers, runners and skiers were examined as regards functional capacity (maximal oxygen consumption measured during graded work load on a horizontal tread-mill), body build and composition (densitometry). Significant differences in mean ages (highest in skiers, lowest in swimmers) and body dimensions, attributable to natural selection, were found (highest length dimensions in swimmers, lowest in weight lifters). According to the specificity of training in individual disciplines studied, runners had lowest body weight and highest lean body mass proportion, and weight-lifters (who had highest relative weight) had lowest lean body mass proportion. Highest values of ventilation, breathing frequency, maximal oxygen consumption and oxygen pulse in skiers simultaneously with lowest pulse frequency were found; the reverse applies for weight lifters. Mutual relationships between somatic and functional characteristics in individual groups were evaluated.     

Fatigue during dynamic muscle contractions in male sprinters and marathon runners: relationships between performance, electromyographic activity, muscle cross-sectional area and morphology

Knee extensor fatigue and endurance during repeated maximum isokinetic manoeuvres were studied in five sprinters and five marathon runners, all males. Fatigue and endurance were expressed in terms of output (contractional work, CW) and input (integrated electromyograms, iEMG), and was related to muscle fibre composition of m. vastus lateralis and to cross-sectional area (CSA) of m. quadriceps. The initially performed contractional work was positively related to the calculated absolute type II fibre area of m. vastus lateralis, but not to the cross-sectional area of m. quadriceps. During the first 25 contractions, sprinters fatigued, with a slope of decline in contractional work that was correlated to the absolute type II fibre area, also after correction of performed work for CSA of m. quadriceps. As the electromyographic activity decreased less than the contractional work, a drastic fall in the CW/iEMG ratio was found in the sprinter group. Three out of five sprinters could perform less than 50 knee extensions, due to subjective discomfort in tested thighs. In contrast, all marathon runners could, after a minor similar decline in electromyographic activity and contractional work during the first part of the experiment, maintain a steady-state endurance level of CW and iEMG throughout the test (200 knee extensions). In conclusion, fatigue during isokinetic maximal knee extensions is closely related to the muscle structure of m. vastus lateralis.     

Renal and cardiovascular responses to water immersion in trained runners and swimmers

The purpose of this study was to determine if fluid-electrolyte, renal, hormonal, and cardiovascular responses during and after multi-hour water immersion were associated with aerobic training. Additionally, we compared these responses in those who trained in a hypogravic versus a 1-g environment. Seventeen men comprised three similarly aged groups: six long-distance runners, five competitive swimmers, and six untrained control subjects. Each subject underwent 5 h of immersion in water [mean (SE)] 36.0 (0.5)°C to the neck. Immediately before and at each hour of immersion, blood and urine samples were collected and analyzed for sodium (Na), potassium, osmolality, and creatinine (Cr). Plasma antidiuretic hormone and aldosterone were also measured. Hematocrits were used to calculate relative changes in plasma volume (%V _pl). Heart rate response to submaximal cycle ergometer exercise (35% peak oxygen uptake) was measured before and after water immersion. Water immersion induced significant increases in urine flow, Na clearance (C _Na), and a 3–5% decrease in V _pl. Urine flow during immersion was greater (P < 0.05) in runners [2.4 (0.4) ml · min^–1] compared to controls [1.3 (0.1) ml · min ^–1]. However, %A V _pl, C _Cr, C _Na and during immersion were not different (P > 0.05) between runners, swimmers, and controls. After 5 h of immersion, there was an increase (P < 0.05) in submaximal exercise heart rate of 9 (3) and 10 (3) beats · min^–1 in both runners and controls, respectively, but no change (P > 0.05) was observed in swimmers. Since swimmers did not experience elevated exercise tachycardia following water immersion compared to runners and sedentary controls, we conclude that exercise training in a hypogravic environment attenuates the acute cardiovascular adaption to microgravity. This effect of hypogravic aerobic training was not associated with the degree of hypovolemia and associated diuresis and natriuresis.     

Second metacarpal cross-sectional geometry: Rehabilitating a circular argument

Radiogrammetry of the second metacarpal has long served as a measure of normal and abnormal bone growth and aging, functional asymmetry, and fracture risk in osteoporosis. The method relies on algebraic interpretation (circular or elliptical models) of uni- or biplanar radiographic images. This paper tests the conformance of these models with actual measures of metacarpal geometric variation in a sample of 356 bones from an historic archaeological sample. Both the circular and elliptical models significantly over-estimate actual values for all variables (e.g., total area (3.05% and 9.42%, respectively) and cortical area (7.25% and 12.25%), bending rigidity about the mediolateral (13.88% and 20.92%) and anteroposterior axes (17.35% for the elliptical model). The greater degree of systematic bias found for the elliptical model is contrary to results of an earlier study (Lazenby, 1997), and suggests that sample composition can influence the method error associated with a particular approach. The import of radiogrammetric bias will depend on the degree of shape variation among samples compared (e.g., left vs right, male vs female, etc.), which in most cases cannot be predetermined. Consequently, reduced major axis equations were derived from regressing actual on estimated values for total area (TA), cortical area (CA) and two measures of bending rigidity (Ix, Iy) in order to permit adjustment for radiogrammetric error associated with these algebraic models. Application of these formulae to a hold-out sample showed no significant differences between actual and predicted values. Am. J. Hum. Biol. 10:747–756, 1998. © 1998 Wiley-Liss, Inc.     

Ulnar and tibial bending stiffness as an index of bone strength in synchronized swimmers and gymnasts

The purpose of this study is to compare a mechanical property of bone in world-class female athletes with different loading histories. Bone bending stiffness or EI (E is the modulus of elasticity and I, the moment of inertia) was measured noninvasively with the mechanical response tissue analyzer, that analyzes the response of bone to a vibratory stimulus. We evaluated the ulna, ulnar width, wrist density and tibia in 13 synchronized swimmers (SYN), eight gymnasts (GYM) and 16 untrained women (UNT) of similar age. Muscle strength in the flexors and extensors at elbows and knees was measured in the athletes. SYN were taller than GYM or UNT (168±0.7 vs. 152±1.1 or 157±1.2 cm, P< 0.01). Ulnar EI, Nm², was similar in SYN and GYM (41±5.4 vs. 42±4.2, NS) and 50% higher than in UNT (27±2.1, P<0.05). Ulnar EI, Nm² was related to ulnar width (r=0.497, P<0.002, n=37) but not to wrist density. Tibial EI, Nm², in SYN and GYM (270±42 vs. 285±49, NS) was similar and more than twice as high as in UNT (119±6; p<0.05). Knee flexor strength measured at 60° s^–1 and elbow extensor strength at 200° s^–1 correlated with tibial EI (r=0.44 and 0.41, P<0.05). In spite of different loading histories, the tibiae and ulnas of world-class athletes showed similar high values for bending stiffness that exceeded values in untrained women. EI in the ulna could be related to bone width and in the tibia, to muscle strength.     

Hematological changes following a marathon race in male and female runners

Summary The subjects of this experiment were well-trained men (6) and women (4) participating in a marathon race in Phoenix, Arizona, on a cool, cloudy, windy day. Venous blood was collected one week prior to the run, immediately after, and 4,8, and 24 h after the race. There were no significant changes in hematocrit, hemoglobin, or red blood cell counts following the race. The sample collected immediately after the race showed a pronounced leucocytosis. Differential counts showed that this increase in white blood cell count was limited to polymorphonuclear cells, suggesting that an inflammatory response to stress of the race was involved. Percentage changes in blood volume, red blood cell volume, and plasma volume were calculated from hematocrit and hemoglobin changes. These changes showed that there was reduction of plasma volume of 8% for females and 13% for males immediately after the race, with return to initial values within 8 h. We suggest that the increase in protein following the race was contributed by the flow of lymph from muscle to the vascular compartment.This study was supported by an Arizona State University faculty grant-in-aid; the Dean's Research Fund, Arizona State University; and Technicon Corporation (Terrytown, NY)     

The determinants of performance in master swimmers: a cross-sectional study on the age-related changes in propelling efficiency, hydrodynamic position and energy cost of front crawl

The decrease in swimming performance (v _max) that occurs with age is a not only consequence of the physiological decrease in maximal metabolic power ( ${\dot{E}}_{\it max}$ ) but can also be expected to depend on an increase in the energy cost of swimming (C) ${\nu}_{\rm max} = {\dot {E}}_{\rm max}/C.$ In turn, for a given speed and stroke C?=?W _d?/?(η_Pη_o) where W _d is hydrodynamic resistance, η_P is propelling efficiency and η_o is overall efficiency. The aim of this study was to measure C in 47 male masters (31–85?years old) swimming the front crawl at sub-maximal, aerobic, speeds. During the experiments propelling efficiency and projected frontal area (A _eff, an index of W _d) were also determined by kinematic analysis. “Elder” masters (60–80?years) swam at a significantly slower pace (0.65 vs. 0.91?m?s^?1), with a lower η_P (0.23 vs. 0.31) and a larger A _eff (0.39 vs. 0.23?m²) than “younger” masters (30–60?years). No significant differences in C (1.45?kJ?m^?1, on the average) were observed as a function of age or speed, but C values were significantly higher than those assessed in young elite swimmers at the very same speeds; the difference increasing with age with a rate of 0.75?% per year. With the due considerations (in this study the observed changes in η_P, A _eff and C can be either attributed to changes in speed or age) these data confirm the hypothesis that an increase in C contributes to the decrease in swimming performance that occurs with age.     

Region-specific differences in Achilles tendon cross-sectional area in runners and non-runners

The present study examined the cross-sectional area (CSA) of the Achilles tendon in subjects who repeatedly exposed their tendons to large loads (habitual runners) compared to control subjects (non-runners). Six male habitual runners [36 (7) years, 70.9 (4.4) kg and 1.84 (0.05) m, ±SD] who had performed distance running (~80 km per week) for the last 5 years were compared to six non-runners [34 (3) years, 81.2 (8.7) kg and 1.81 (0.02) m, ±SD]. Tendon CSA was obtained from MR images obtained with the ankle in a neutral position (90°). The most proximal aspect of the tuberosity of calcaneus was used as a landmark to standardize the levels of images: the most distal image (1) was obtained 10 mm above the proximal tuberosity of calcaneus, and the most proximal image (7) was obtained 70 mm above the proximal tuberosity of calcaneus. There was a significant difference in CSA along the length of the tendon both in runners (P<0.001) and non-runners (P<0.01). In non-runners and runners the CSA of the most distal part was 51% and 85% greater than the most proximal part of the tendon, respectively. Furthermore, there was a difference in tendon CSA between the groups, such that runners had a greater CSA (36%) than non-runners at the most distal part of the tendon (P<0.05). The greater CSA in the distal tendon may reflect differences in structural properties along the length of the human Achilles tendon, while the greater CSA in runners compared to non-runners may indicate a region-specific hypertrophy in response to the habitual loading of running.     

Comparison of the gut microbiota of short-term and long-term medical workers and non-medical controls: a cross-sectional analysis

ObjectivesThe hospital environment has been implicated in the enrichment and exchange of pathogens and antibiotic resistance, but its potential in shaping the symbiotic microbial community of hospital staff is unclear. This study was designed to evaluate the alteration of the gut microbiome in medical workers compared to non-medical controls.MethodsA prospective cross-sectional cohort study was conducted in the intensive care unit (ICU) and other departments of a centre in north-eastern China. Faecal samples of 175 healthy medical workers—short-term (1–3 months) workers (n = 80) and long-term (>1 year) workers (n = 95)—and 80 healthy non-medical controls were analysed using 16S rRNA amplicon sequencing. The hospital environmental samples (n = 9) were also analysed.ResultsThe gut microbiomes of medical workers exhibited marked deviations in diversity and alteration in microbial composition and function. Short-term workers showed significantly higher abundances of taxa such as Lactobacillus, Butyrivibrio, Clostridiaceae, Clostridium, Ruminococcus, Dialister, Bifidobacterium, Odoribacter, and Desulfovibrio and lower abundances of Bacteroides and Blautia than the controls. Long-term workers showed higher abundances of taxa such as Dialister, Veillonella, Clostridiaceae, Clostridium, Bilophila, Desulfovibrio, Pseudomonas, and Akkermansia and lower abundances of Bacteroides and Coprococcus than the controls. The medical workers' department (ICU versus non-ICU) and position (resident doctor versus nursing staff) also impacted their gut microbiome. Compared with the non-ICU workers, workers in the ICU showed a significant increase in the abundances of Dialister, Enterobacteriaceae, Phascolarctobacterium, Pseudomonas, Veillonella, and Streptococcus and a marked depletion of Faecalibacterium, Blautia, and Coprococcus. In contrast with the nursing staff, the resident doctors showed a significant increase in Erysipelotrichaceae and Clostridium and a decrease in Bacteroides, Blautia, and Ruminococcus in the gut microbiome. Moreover, we found that the microbiota of hospital environments potentially correlated with the workers' gut microbiota.ConclusionsOur findings demonstrated structural changes in the gut microbial community of medical workers.     

Orthostatic hypotension,diabetes, and falling in older patients: a cross-sectional study

Background

Although orthostatic hypotension (OH) is more prevalent in old age, and in patients with diabetes, the prevalence of OH in older patients with type 2 diabetes mellitus is unknown.

Aim

To establish the prevalence of OH, and its association with falling, in home-dwelling older participants with and without type 2 diabetes.

Design and setting

A cross-sectional study in primary care in the Netherlands.

Method

A total of 352 patients with type 2 diabetes, and 211 without participated in this study. OH was defined as a fall in blood pressure of at least 20 mmHg systolic or 10 mmHg diastolic after either 1 or 3 minutes in an upright position. Feelings of dizziness, light-headedness, or faintness during the standing period were documented as orthostatic complaints. Fall risk was assessed with a validated risk profile instrument.

Results

The prevalence of OH was 28% (95% CI = 24% to 33%) and 18% (95% CI = 13% to 23%) in participants with and without type 2 diabetes, respectively. OH was not related to falling, while the presence of orthostatic complaints in itself was associated with both previous fall incidents as well as a high fall risk, even after adjustment for OH. The adjusted odds ratios were 1.65 (95% CI = 1.00 to 2.72) and 8.21 (95% CI = 4.17 to 16.19), respectively.

Conclusion

OH is highly prevalent in home-dwelling older people with and without type 2 diabetes. Those with orthostatic complaints had an increased risk for falling, whereas those with OH were not.     

Comparison of sympatho-adrenergic regulation at rest and of the adrenoceptor system in swimmers,long-distance runners,weight lifters,wrestlers and untrained men

Summary The effects of different physical training regimes on the plasma catecholamine values at rest and the density and responsiveness of adrenergic receptors at rest were investigated. The changes during well-defined training periods of swimmers, long-distance runners, weight lifters and wrestlers were compared with untrained male volunteers. The training of swimmers and long-distance runners, building up endurance, resulted in a significantly lower basal plasma norepinephrine (NE) concentration and a significantly or possibly lower ratio NEEPI (epinephrine). Both values indicated reduced sympathetic activity and resulted also in a significantly lower -receptor density and a higher ₂-receptor sensitivity compared with the other groups investigated. However, swimming-specific characteristics provoked labile hypertensive blood pressure regulation with an unchanged heart rate in swimmers. Static training of weight lifters, building up power, also led to a lower NE concentration compared with untrained subjects, whereas -receptor density was unchanged and ₂-receptor density and sensitivity were decreased. Elevated blood pressure values were observed in weight lifters and swimmers due to a reduced baroreceptor sensitivity. The dynamic training of wrestlers affected only basal heart rate and ₂-receptor sensitivity, both of which were decreased. Different kinds of physical training caused various adaptations of the basal activity of the autonomic nervous system in which adrenergic receptors also became adapted. In this context, the stronger adrenergic circulatory component of overall sympathetic activity at rest in swimmers and long-distance runners resulted in lower -receptor density, and the reduced noradrenergic component sensitized ₂-receptors.     

Plasma noncholesterol sterols in male distance runners and sedentary men

Summary Plasma lathosterol concentration is taken to be an index of the rate of cholesterol synthesis and plasma concentrations of plant sterols just as campesterol and betasitosterol are taken to be indeces of cholesterol absorption efficiency. These noncholesterol sterols were measured in plasma from 14 male distance runners and 10 sedentary men. Plasma lathosterol concentration was 30% lower (P<0.02) and plasma betasitosterol concentration was 33% higher (P<0.02) in the runners compared to the sedentary men. Plasma concentrations of lathosterol and plant sterols were inversely and significantly (P<0.05) correlated in both the runners and the sedentary men. Plasma plant sterol concentrations were correlated positively and significantly (P<0.01) with plasma high density lipoprotein cholesterol (HDL-C) concentrations in the runners and sedentary men combined. These findings suggest that more efficient cholesterol absorption may lead to higher plasma plant sterol concentrations and may contribute to lower cholesterol synthesis rates, reduced concentrations of plasma lathosterol and higher plasma HDL-C concentration in distance runners.     

Prevalence of nasal polyposis in France: a cross-sectional, case-control study

BACKGROUND: The prevalence of nasal polyposis (NP) has never been established in France due to the lack of diagnostic tools for population-based studies. METHODS: Using a recently validated questionnaire/algorithm (90% specificity and sensitivity) in a population-based random sample, the present cross-sectional, case-control study allowed to determine NP prevalence and describe the principal aspects of NP epidemiology. A total of 10 033 subjects (>/=18 years) were screened. After identification of subjects with NP and those without, another questionnaire was submitted to NP patients only for further data collection. Controls were individuals without NP, matched by gender and age to NP patients. RESULTS: Nasal polyposis prevalence was 2.11% (95% CI 1.83-2.39). NP patients (n = 212, 45% males) were aged 49.4 +/- 17.6 years. No gender preponderance was observed, but NP tended to increase with age. Mean duration of nasal symptoms was 22.4 +/- 15.7 years. Among the 145 patients having already seen a doctor for their symptoms, 77.2% have been referred to a specialist, and 18.6% had a diagnosis of NP. Rhinorrhoea was reported by 39.9% of NP patients, blocked nose by 30.8%, and anosmia by 28.9%. Only 6.9% reported facial discomfort while 24.6% complained about general discomfort. Most NP patients (61.3%) had a pharmacological treatment, a nasal spray for the major part (76.9%). CONCLUSION: The present study provides valuable and reliable information on NP epidemiology in France; the collected information are in accordance with most published international data.     

Marriage duration, marital adjustment and psychological symptoms: a cross-sectional study

One hundred and nine couples completed questionnaire measures of psychological symptoms, personality, and marital adjustment. They were divided into groups of short, intermediate, and long marriage duration. Psychological symptoms and marital adjustment remained fairly stable over time, although wives scored significantly worse than husbands on most measures in the intermediate duration group. In the short marriages, half the variance in marital satisfaction was predicted by the partner's marital questionnaire score, but when this variable was eliminated from the regression equation, psychological symptoms (phobic anxiety in wives and depression in husbands) were the main predictors of marital satisfaction. In the intermediate group, hostility levels were the main predictors of marital satisfaction. In the long marriages, marital satisfaction was predicted mainly by personality factors (assertiveness in husbands and personal flexibility in wives) and by levels of generalized anxiety. The findings suggest that couples who constructively resolve difficulties in expressing hostility within marriage are more likely to remain married than those who fail to do so.     

Vascular volumes and hematology in male and female runners and cyclists

To examine the hypothesis that foot-strike hemolysis alters vascular volumes and selected hematological properties is trained athletes, we have measured total blood volume (TBV), red cell volume (RCV) and plasma volume (PV) in cyclists (n?=?21) and runners (n?=?17) and compared them to those of untrained controls (n?=?20). TBV (ml?·?kg^?1) was calculated as the sum of RCV (ml?·?kg^?1) and PV (ml?·?kg^?1) obtained using ⁵¹Cr and ¹²⁵I-labelled albumin, respectively. Hematological assessment was carried out using a Coulter counter. Peak aerobic power (V˙O_2peak) was measured during progressive exercise to fatigue using both cycle and treadmill ergometry. RCV was 15% higher (P?n?=?12] and runners [35.3 (0.98); n=9] compared to the controls [30.7 (0.92); n?=?12]. Similar differences existed between the female cyclists [28.2 (2.1); n?=?9] and runners [28.4 (1.0); n?=?8] compared to the untrained controls [24.9 (1.4); n?=?8]. For the male athletes, PV was between 19% (cyclists) and 28% (runners) higher (P?P?V˙O_2peak (ml?· kg^?1?·?min^?1) was higher (P?V˙O_2peak for both cyclists and runners, no differences were found between the athletic groups within a gender. Since the vascular volumes were not different between cyclists and runners for either the males or females, foot-strike hemolysis would not appear to have an effect on that parameter. The significant correlations (P?V˙O_2peak and RCV (r?=?0.64 and 0.64) and TBV (r?=?0.82 and 0.63) for the males and females, respectively, suggests a role for the vascular system in realizing a high aerobic power.