Effects of 3-month Qigong exercise on heart rate variability and respiration in anxious college students.

OBJECTIVE: This longitudinal study aimed to investigate the effects of Qigong on the anxiety state, heart rate variability (HRV), and breathing of anxious college students. METHODS: A total of 37 individuals (18-25 years old) were randomly allocated to the control (n = 19) and intervention (n = 18) groups. Qigong interventions were conducted five times weekly for 12 weeks, with each session lasting 60 min. Hamilton Anxiety Scale, Fatigue Scale 14, Pittsburgh Sleep Quality Index, and 36-item Short Form Survey, HRV, and respiration data were collected before and after the 3-month intervention. RESULTS: Individuals who participated in the three-month Qigong exercise intervention showed a significant reduction in anxiety, particularly mental anxiety (p < 0.05). Subjects in the intervention group presented a decrease in skin temperature (p < 0.05) and an increase in blood volume pulsation (p < 0.05). Meanwhile, HRV exhibited a significant increase in the standard deviation of interbeat interval before and after comparisons (p < 0.05) and between the two groups (p = 0.039) and a reduction in the normalized low-frequency power after the intervention. Moreover, the intervention group experienced increased abdominal breathing depth and abdominal breathing per minute (p < 0.05). CONCLUSION: These findings indicate that Qigong is an effective mind-body exercise strategy for relieving anxiety. HRV and breathing were improved accordingly among college students after the completion of the 3-month Qigong program.

Patellofemoral Pain, Q-Angle, and Performance in Female Chinese Collegiate Soccer Players.

Background and objective: Female sports injuries have been neglected by science, and few relevant studies have considered female subjects. Knee pain in female soccer players is more common than in male soccer players. The number of days of absence from training and competition has been shown to be higher in females than males. The reporting of knee pain is common in female soccer players, but whether knee pain is associated with morphological features is unclear. The Q-angle of the knee has been hypothesized to be a causal factor in knee pain. Asian females have shown higher levels of valgus than non-sporting Caucasian populations, but no data exist for female Chinese players. The aim of our study was to investigate whether there are associations between knee pain, the Q-angle of the lower limb, jump performance, play time, and perceived exertion in female Chinese collegiate soccer players. Materials and Methods: We measured the Q-angle, patellofemoral/anterior knee pain (SNAPPS questionnaire), and CMJ and SJ performance of 21 subjects (age: 20.09 ± 1.13 years, weight: 56.9 ± 6.26 kg, height: 164.24 ± 4.48 cm, and >10 years of practice) before and after a match; Borg scale and play time results were also recorded. Results: We found that our studied group had higher Q-angles in comparison to other ethnic groups reported in the literature, as well as an association of the Q-angle with the age, height, and weight of the players; however, contrary to other studies, we did not find any association between the Q-angle and knee pain, jumps, play time, or perceived exertion. Knee pain was not associated with any of the measured variables. Conclusions: Female Chinese soccer players showed higher Q-angles than players of other ethnic groups, a result that was associated with anthropometrics. The Q-angle was not found to be associated with knee pain, for which the sole determinant was body height.

Correlations of skinfold thicknesses and circumferences at exactly defined body sites with leptin in 10-12-year-old boys with different BMIs.

The aim of this study was to investigate the correlations of leptin with values of skinfold thicknesses and circumferences in 10-12-year-old boys (N = 248) and these correlations were additionally studied in boys with different BMI subgroups (normal N = 190, overweight N = 34 and obese N = 24). In total, 9 skinfolds and 13 circumferences were measured using the recommendations of ISAK. Fasting leptin concentrations were also determined. No significant differences emerged between the three subgroups in age and Tanner stage. Skinfold thicknesses, circumferences and leptin concentrations were significantly higher in overweight and obese groups. In the total group, the correlation (partial correlation, eliminating age and Tanner stage) between separate skinfold thicknesses and leptin was higher than r = 0.70. The sum of 9 skinfold thicknesses correlated significantly to leptin in all groups (r = 0.558-0.779). In the obese group, triceps, biceps and front thigh skinfold thicknesses did not correlate (p > 0.05) with leptin. In the total group, all measured circumferences correlated significantly to leptin concentration (r = 0.328-0.724). However, in the obese group, the measured circumferences did not correlate to leptin (p > 0.05). Waist-to-hip ratio correlated with leptin only in the total group of boys. It was concluded that as a rule, close correlations emerged between leptin and skinfold thicknesses and circumferences. The strongest correlation with leptin was found with the sum of 9 skinfolds and waist-to-hip ratio.

Blackcurrant Supplementation and Habitual Physical Activity Enhance Functional Capacity and Quality of Life in Previously Sedentary Older Women.

BACKGROUND: Loss of functional capacity negatively impacts the quality of life in older adults. OBJECTIVE: This single-site randomized controlled study examined whether short- (one week) and long-term (three months) blackcurrant supplementations combined with habitual physical activity would improve functional capacity and quality of life in previously sedentary older women. METHODS: Thirty sedentary, healthy older women were randomly assigned to receive blackcurrant supplementation (400 mg of blackcurrant extract) (Polyphenol group, n=15; 74.2±10.0 years) or no supplementation (capsules of 400 mg of corn flour) (Placebo group, n=15; 72.8±8.7 years). Each group consumed two capsules daily for one week and three months, with a washout period of one week between the two phases. The polyphenol group was required to increase habitual activity levels. Participants underwent a functional capacity assessment consisting of a six- minute walk, sit-to-stand test, Berg balance scale measurement and quality of life evaluation with the Scale of Life Satisfaction Index (LSI) at the start, after one week, and after three months of supplementation. RESULTS: Walking distance and time to sit-to-stand improved by 2.5% (p=0.005) and 7.5% (p=0.005), respectively, after one week in the polyphenol group. After 3 months, walking distance in the six-minute walk test increased by 12.3% (p=0.001) while the time to sit-to-stand decreased by 16% (p=0.002) in the polyphenol compared to placebo group, respectively. No differences in Berg balance scale were observed. Quality of life, indexed by LSI, improved by 39% (p=0.001) in the polyphenol compared to the placebo group. CONCLUSION: Blackcurrant supplementation, combined with habitual activity, may enhance functional capacity and quality of life in older women, offering a potential strategy to maintain independence. However, future studies should address longer durations to validate these findings.

Moderate physical activity correlates with elevated leptin in physically active 10-12-year-old boys with normal BMI.

The aim of this study is to examine the relations between physical activity of differing intensity and duration with body energy-balance hormone leptin in 10-12-year-old boys (N = 94) who participated in moderate-to-vigorous physical activity at least four to five times per week. The boys reported their physical activity using a questionnaire. They had normal body mass index (BMI, kg/ m2), and were at Tanner Stage 2 of development. Boys were divided into three subgroups by leptin levels: normal serum leptin (M +/- .5 SD, n = 44, 1.2-3.9 ng/ml), low leptin (< or = M - .5 SD; n = 31, < 1.2 ng/ml), and high leptin (> or = M + .5 SD; n = 19, > 3.9 ng/ml). There were significant differences between subgroups in anthropometric parameters and serum leptin levels, but not in physical activity. A significant correlation was found between leptin and moderate physical activity of at least five times per week for at least 30 minutes each time in the high leptin group (r = .61). In conclusion, the correlations between physical activity and leptin are weak; only moderate physical activity was correlated with leptin levels in the high leptin

Performance and recovery: stress profiles in professional ballroom dancers.

Like other athletes, ballroom dancers often compete in short time in different countries under condition of high stress, subjecting them to risk of injury and burnout. In the present study, we measured the aerobic and anaerobic capacities (both during dance and during a simulated ballroom competition), agility, hand and abdominal strength, jumping capacity, flexibility, and balance in 16 top-level couples of ballroom dancers (8 males, 8 females). The in-season level of perceived stress and recovery was assessed using the Rest Q 76 questionnaire, and the relationship with aerobic and anaerobic capacity and with the other tests was studied. Our results show a very high level of aerobic/anaerobic fitness in this population, as well as a high level of stress in males. Balance and experience (age of the subjects) appear to be key characteristics linked to the position in the IDSF World Ranking (world ranking points = 8.67 x age + 5.86 x balance + 1174.65; R2 = 0.740). Emotional stress (r = 0.83, p = 0.04), social stress (r = 0.72, p = 0.032), and sleep quality (r = 0.92, p = 0.001) scales of the Rest Q appear also to be linked with balance but only in females.

Daytime sleepiness in Chinese professional, semi professional and students soccer players in the Shanghai lockdown.

PURPOSE: April-May 2021 Shanghai city was under strict lockdown. Soccer players suffered from the restrictions, being unable to train and have a social life. The aim of this study was to compare differences in daytime sleepiness between genders and qualification levels in a cohort university Chinese soccer player under 0 Covid policy restrictions in the urban area of Shanghai. METHODS: 491 questionnaires of Epworth Sleepiness Scales (ESS) were compiled online by male and female Soccer Students (SS), Semi-Professional players (SP) and Professional Players (PP) during the ongoing restriction measures post Shanghai lockdown. ANOVA was performed for players levels and gender. RESULTS: Significant differences were found between the 3 levels and between males and females. PP showed a very low score in the ESS (5,97) well below the threshold of 8 for daytime sleepiness, while SS and SP showed an ESS score above the threshold. Female showed higher scores in comparison to males. Differences between males and females reflect the confinement conditions in the ESS items, showing more difference in the item of ESS which are related with indoor situations. CONCLUSIONS: This study shows the first data on sleepiness in Chinese soccer players of different level of qualification immediately post lockdown condition. Professional male's players sleepiness was lower, than females, SS and SP after the exceptional lockdown measures. The reasons can reside in the more ordered lifestyle of PP in comparison to SS and SP, which mitigated the effects of the lockdown. Our results suggest that measures to improve sleep in females' soccer player should be adopted if these exceptional conditions will happen again.

Health Consequences of Intensive E-Gaming: A Systematic Review.

The aim of this review is to examine the links among the different factors that determine harmful or even deadly events in professional and semiprofessional intensive Esports players. Cases of serious injuries or even death in young (<35 years old) male professional Esports players are reported every year. Fatalities and injuries in professional Esports players (PEGS) have only affected male players, and these events have mostly been concentrated in Asia. Studies in the literature have reported several causes and mechanisms of injuries. Links between injuries and previous comorbidities have emerged from the extant literature; obesity and/or metabolic disorders, seizures (associated with overstimulation of the eyes), heart malfunctions, high basal and abrupt increases in systolic blood pressure (SBP), prolonged stress, and poor posture have been associated with injuries. Several clinical signs have been identified and the question emerges whether or not self-regulation by Esports associations or public health authorities is necessary.

[Bone ultrasonography in kidney disease: applications and limitations]. / L'ultrasonografia ossea in nefrologia: applicazioni e limiti.

Quantitative ultrasound (QUS) of the bone is a technique that is generating great interest among bone structure researchers because of its intrinsic features. Its safety and low cost make it an ideal technique for repeated measurements over time such as in chronic disease or when it is necessary to monitor the effects of prescribed therapies. The method was developed for the study of osteoporosis and the sites of measurement are all peripheral, including the distal diaphyses and metaphyses of the phalanges, calcaneus, radius and tibia. QUS parameters, however, cannot be used directly for the diagnosis of osteoporosis according to the WHO criteria, although many authors have shown that ultrasound parameters, particularly those of calcaneal QUS, can predict the risk of osteoporotic fractures independently of MBD. Very promising results with the use of QUS have been obtained in corticosteroid-induced osteoporosis, rheumatoid arthritis, Cushing's syndrome, cystic fibrosis, osteomalacia, thalassemia and osteopenia related to parenteral nutrition. QUS can also monitor the effectiveness of therapy in various pathological conditions. In nephrology the combined use of phalangeal QUS and biochemical markers of bone turnover allows adequate follow-up of patients on dialysis and renal transplant recipients with alterations or disorders of the bone.

[Prevalence and control of hypertension in chronic hemodialysis patients: results of a single-centre clinical audit]. / Prevalenza e controllo dell'ipertensione arteriosa nei pazienti in trattamento emodialitico cronico: risultati di un audit clinico monocentrico.

Hypertension (HTN) is very common in chronic hemodialysis patients, with a prevalence of 72%, a very poor control and an annual mortality of 23%. We report the results of a clinical audit on prevalence and control of HTN in our hemodialysis patients. The following parameters in a cohort of 89 patients were assessed in one-month observational study, conducted in October 2010: blood pressure (BP) before the beginning (preHD BP) and after the end of the treatment (postHD BP), age, sex, comorbidity, serum hemoglobin (Hb) levels, plasma and dialysate sodium levels, interdialytic weight gain (IWG), serum parathyroid hormone (PTH) levels, prescription of erythropoiesis stimulating agents (ESA) and of antihypertensive drugs. In agreeement to the current guidelines, patients with preHD BP ≤140/90 mmHg and postHD BP ≤130/80 mmHg were considered normortensive. Forty-nine patients (55%) were found to be hypertensive. The following comorbidities, graded as 1+ to 3+, were detected: ischemic/hypertrophic cardiopathy, dyslipidemia, peripheral arteriopathy, diabetes mellitus. Only 14.3% of patients achieved both preHD and postHD BP targets. Compared to patients whose BP was not controlled, those achieving BP targets were younger, had lower dialysate sodium levels and showed a greater IWG. No significant difference there was in serum Hb levels, plasma sodium levels, serum PTH levels, prescription of antihypertensive drugs and ESA. Our data confirm the high prevalence of HTN and the unsatisfactory BP control in hemodialysis patients. A low-salt diet, probing for dry-weight and the antihypertensive medication may help to achieve the BP control.

Recommendations for Resuming PA after Prolonged Rest in Children and Adolescents: A Systematic Integrative Review of Relevance for Immunity.

This systematic integrative review aims to summarize the protective effect of PA on children and adolescents, with special reference to the immune system. Periods of prolonged inactivity in children and adolescents are rare and due to exceptional events, such as illness or environmental circumstances, e.g., natural disasters, wars, or epidemics. The recent COVID-19 pandemic forced billions of children in developmental ages into inactivity. This exceptional event was the reason for studying the compensational behavioral strategies adopted by children and adolescents to counteract physical inactivity. Several studies showed the rise of spontaneous physical activity (PA) among children and adolescents to compensate for sedentarism. However, for some children, sedentarism could in turn foster other sedentarism. With the restart of "normal daily life" worldwide, a question is posed on both how to resume PA without causing damage and how to improve the immune response. Some key points emerged from the literature. Children must resume PA gradually using different methods, considering age, sex, health status, and the presence of overweight conditions. Immunity can be stimulated with PA by aerobic exercise, resistance training, flexibility exercise, relaxation, and coordinative exercises.

The Problem of Effort Distribution in Heavy Glycolytic Trials with Special Reference to the 400 m Dash in Track and Field.

BACKGROUND: Biological factors are ultimately responsible for the cessation of effort in short, maximal glycolytic efforts. However, how these factors are sensed by the brain and act in a loop or feedforward way to regulate the distribution of effort is still unclear. METHODS: A systematic review of existing literature on short term glycolytic exercise has been performed on publicly available databases (Google Scholar and Pudmed). RESULTS: The problem of effort termination in fast maximal glycolytic activities after 100 years of research is still open. It is not clear if a central governor of effort exists, if the limitations are in the energy transport and utilization system, or in the psycho-social factors. CONCLUSIONS: The solution probably resides in a mixture of factors, but how the different components interact is still a mystery for science due to the philosophical grounding of the experimental approaches.

Plasma visfatin and adiponectin concentrations in physically active adolescent girls: relationships with insulin sensitivity and body composition variables.

The purpose of this study was to evaluate the associations of visfatin and adiponectin concentrations with insulin resistance and body composition in regularly physically active pubertal girls. In 129 girls, aged 13-15 years (pubertal stages 3-5), visfatin, adiponectin, insulin resistance measured by homeostasis model assessment (HOMA), and body composition measured by dual-energy X-ray absorptiometry were evaluated. Visfatin concentration was related to HOMA and overall adiposity (body mass index, fat mass) markers, whereas adiponectin concentration was related to overall adiposity (fat mass), central adiposity (trunk fat) and fat free mass values. These relationships remained significant (p < 0.05) after adjusting for pubertal stage. Visfatin was independently related to body mass index (beta = 0.936; p = 0.0001) and HOMA (beta = 0.444; p = 0.039) indices, whereas adiponectin was independently related to fat free mass (beta = 0.889; p = 0.003) and trunk fat (beta = -0.468; p = 0.042) values. In conclusion, visfatin could be related to insulin resistance and overall adiposity indices, whereas adiponectin was related to different body composition values in regularly physically active pubertal girls.

Static Body Balance in Children and Expert Adults Ballroom Dancers: Insights from Spectral Analysis of Shifts.

OBJECTIVE: The purpose of this study was to assess the differences in maintaining body balance (influence of different sensorial sub-systems) in a representative sample of active Dance Sport competitors (children and adults). METHODS: Overall, 13 children and 15 high-level adults sport dancers underwent a static equilibrium test on a force platform, in which 17 different parameters were examined, including a spectral analysis of shifts using an FFT algorithm that can assess the contribution of different somatic-sensory systems on maintaining body balance. RESULTS: Younger subjects rely on their somatic-sensory reactions to maintain their balance, while adults rely more on the vestibular system, according to shifts' spectral analysis. No differences were noted between the male and female participants. CONCLUSIONS: Children predominantly use the somatic-sensory system in body balance, while adults make more use of the vestibular system. According to these results and due to the trainability phases, exercises that challenge the somato-sensorial system are recommended to train balance in young dancers, while exercises that challenge the vestibular system are recommended in adult dancers which who have not developed exceptional somato-sensory balance abilities during their growth and training history.

Brain Oxygenation in Post-concussion Combat Sport Athletes.

Purpose: Investigate the feasibility of a non-invasive method to evaluate the physical and cognitive repercussions of long-lasting post-concussion effects in professional combat sports athletes. To help athletes return to professional combat, there is a need for unbiased objective tools and techniques used as a prognostic method of recovery after Sport Related Concussion (SRC). Methods: Six mild Traumatic Brain Injury (mTBI) athletes, age 20 ÷ 43 yr (1 female, 5 males) and 7 not concussed (NC) participants (amateur), age 24 ÷ 38 yr (3 females, 4 males), were tested Inspired/expired gas concentration, Cerebral changes in oxygenated hemoglobin (Δ[HbO2]) and deoxygenated hemoglobin (Δ[HHb]) were measured using near infrared spectroscopy (NIRS) with a 3-step protocol: rest before maximal oxygen uptake (VO2max) test, hypercapnia, and recovery after VO2max test. The brain oxygenation and respiratory parameters of both sample sets were calculated using a non-parametric test (Mann-Whitney U test). Aerobic fitness outcome was quantified through mean average using the Bruce test. Participants performed Fitt's test using a laptop and analysis of medio-lateral and anterior-posterior range of oscillation was carried out via a force platform Romberg test. Results: mTBI group showed statistically significant differences in saturated hemoglobin Δ[HbO2] (p < 0.001) during rest and recovery phase after maximal incremental exercise, in medio-lateral sway eyes open (p = 0.008, NC 25.35 ± 4.11 mm and mTBI 17.65 ± 4.79 mm). VO2max revealed no significant differences between the two groups: NC 47.47 ± 4.91 mTBI 49.58 ± 5.19 ml/kg/min-1. The 2 groups didn't differ for maximum power output (NC 220 ± 34, mTBI 255 ± 50 W). End-tidal fractional concentration of O2 (FetO2 NC15.20 ± 0.41, mTBI 16.09 ± 0.68) throughout hypercapnia, saturated blood hemoglobin (Δ[HbO2]) revealed significant differences with the mTBI group. No differences emerged from Fitt's test. Conclusions: It emerges that NIRS is able to reveal differences in long time outcomes of mTBI. The medio-lateral variations cannot be considered as a marker of long-term damage in athletes specifically trained for balance.

Upper Respiratory Tract Infections in Sport and the Immune System Response. A Review.

Immunity is the consequence of a complex interaction between organs and the environment. It is mediated the interaction of several genes, receptors, molecules, hormones, cytokines, antibodies, antigens, and inflammatory mediators which in turn relate and influence the psychological health. The immune system response of heavily trained athletes resembles an even more complex conditions being theorized to follow a J or S shape dynamics at times. High training loads modify the immune response elevating the biological markers of immunity and the body susceptibility to infections. Heavy training and/or training in a cold environment increase the athletes' risk to develop Upper Respiratory Tract Infections (URTIs). Therefore, athletes, who are considered healthier than the normal population, are in fact more prone to infections of the respiratory tract, due to lowering of the immune system in the time frames subsequent heavy training sessions. In this revision we will review the behavioral intervention, including nutritional approaches, useful to minimize the "open window" effect on infection and how to cope with stressors and boost the immune system in athletes.

ADIPOQ SNP45 associated with lean body mass in physically active normal weight adolescent girls.

UNLABELLED: Recently, two single nucleotide polymorphisms at position 45 and 276 on the adiponectin gene (ADIPOQ) have been recognized as determinants of total adiponectin levels, insulin resistance, and risk for diabetes in various obese populations. OBJECTIVES: The aim of this study was to determine whether these two polymorphisms are indeed determinants in the development of metabolic disorders or whether they are secondary to other confounding factors. METHODS: To do so, we have selected 170 physically active adolescent girls (mean age, 14.03 ± 1.5 years and mean body mass index, 19.98 ± 2.5 kg/m²) devoid of any metabolic diseases or confounding factors, to better attribute any findings to genotype effects. Concentration of adiponectin, insulin, and glucose were determined from blood samples with appropriate kits. Body fat parameters were evaluated with dual-energy X-ray absorptiometry, and genotype was analyzed with DNA extracted from whole blood samples followed by polymerase chain reaction and electrophoresis to separate alleles. RESULTS: Neither single nucleotide polymorphism +45T/G nor +276G/T was related to homeostasis model assessment index or adiponectin levels; however, the presence of the G allele on site 45 favored a significant decrease in lean body mass compared with those who were T homozygous (TG:36.90/TT:41.07 kg, P < 0.05). CONCLUSIONS: Results suggest that the reported increase in the risk of diabetes in subjects that were G allele carriers at site 45 in obese populations compared with normal-weight populations can be linked instead to a change in muscle mass or the muscle itself present in this genotype group.

Development of the Biomechanical Technologies for the Modeling of Major Segments of the Human Body: Linking the Past with the Present.

The knowledge of human body proportions and segmental properties of limbs, head and trunk is of fundamental importance in biomechanical research. Given that many methods are employed, it is important to know which ones are currently available, which data on human body masses, lengths, center of mass (COM) location, weights and moment of inertia (MOI) are available and which methods are most suitable for specific research purposes. Graphical, optical, x-ray and derived techniques, MRI, laser, thermography, has been employed for in-vivo measurement, while direct measurements involve cadaveric studies with dissection and various methods of acquiring shape and size of body segments. The present review examines the literature concerning human body segments' properties for biomechanical purposes starting with a historical examination. It emerges that data obtained in studies on cadaveric specimens are still accurate in comparison to more recent technologies, whilst technological tools currently available are manifolds, each one with proper advantages and disadvantages. Classical studies were focused mainly on white men, while in recent years, the available data on body segments have been extended to children, women, and other races. Additionally, data on special populations (obese, pregnant women) are starting to appear in the scientific literature.

Physical development and swimming performance during biological maturation in young female swimmers.

The present study analyzed the development of physiological, biomechanical and anthropometrical parameters in young female swimmers and assessed the effect of these parameters on swimming performance during biological maturation. In total, 26 female swimmers participated in the study in which data were annually collected for two consecutive years. Body composition, basic anthropometrical parameters and biological age were measured. During the 400-m front-crawl swimming, the energy cost of swimming and stroking parameters were assessed. Peak oxygen consumption (VO2(peak)) was assessed by means of the backward-extrapolation technique recording VO2 during the first 20 sec of the recovery period after a maximal trial of 400-m distance. During the 2-year follow-up study period, age, height, body mass, body fat %, fat free mass, bone mineral mass, total bone mineral density, arm span and biological maturation values significantly increased during each year (p < 0.05). The tracking of the physical characteristics measured over the 2-year study period was relatively high (r > 0.694), except for the body fat% (r > 0.554). The tracking of the Tanner stages was also high (r = 0.759-0.780). Stepwise regression analyses showed that biomechanical factors (R2 > 0.322; p < 0.05) best characterized the 400-metre swimming performance in young female swimmers, followed by bioenergetical (R2 > 0.311; p < 0.05) and physical (R2 > 0.203; p < 0.05) factors during all three measurement times.

Longitudinal development of physical and performance parameters during biological maturation of young male swimmers.

The aim of the study was to examine the development of specific physical, physiological, and biomechanical parameters in 29 young male swimmers for whom measurements were made three times for two consecutive years. During the 400-m front-crawl swimming, the energy cost of swimming, and stroking parameters were assessed. Peak oxygen consumption (VO2 peak) was assessed by means of the backward-extrapolation technique recording VO2 during the first 20 sec. of recovery period after a maximal trial of 400-m distance. Swimming performance at different points of physical maturity was mainly related to the increases in body height and arm-span values from physical parameters, improvement in sport-specific VO2 peak value from physiological characteristics, and improvement in stroke indices on biomechanical parameters. In addition, biomechanical factors characterised best the 400-m swimming performance followed by physical and physiological factors during the 2-yr. study period for the young male swimmers.