1,721,023 research outputs found
Investigating body dimension and composition across diverse populations with traditional and advanced techniques.
No full textIn questo progetto di dottorato sono stati condotti sette studi: “Effetto di differenti attività sportive a carico d’impatto sulla composizione corporea di femmine prepuberi”, “Variazioni della composizione corporea in calciatori professionisti nel corso di una stagione agonistica”, “Effetti della qualità dell’osso sulla velocità di tiro nella pallamano”, “Studio della composizione corporea in atleti spinalizzati praticanti sport in carrozzina”, “Analisi cinematica del servizio nel tennis in carrozzina: implicazioni sul sistema di classificazione”, “Antropometria, composizione corporea e prestazione in giovani giocatori di pallacanestro in carrozzina” e “Misurazione attraverso procedure di antropometria digitale tridimensionale della riduzione di massa grassa indotta da esercizio fisico in donne obese”. Quattro degli studi sopraelencati sono pubblicati o in fase di stampa su riviste scientifiche internazionali. Negli studi sopraesposti sono stati indagati parametri relativi a dimensioni corporee e composizione corporea in diverse popolazioni (ginnaste e pallavoliste prepuberi, calciatori professionisti, giocatori di pallamano di livello élite e sub-élite e atleti medullolesi praticanti sport in carrozzina) attraverso l’applicazione di tecniche antropometriche tradizionali e tecniche avanzate di imaging, come il densitometro a doppio raggio fotonico (DXA) e lo scanner tridimensionale. L’utilizzo combinato di queste tecniche mi ha permesso di studiare le caratteristiche antropometriche e di composizione corporea in differenti attività sportive per monitorare gli effetti dell’allenamento sulla composizione corporea nell’arco di una stagione agonistica, di analizzare la relazione tra caratteristiche antropometriche e di composizione corporea e specifiche gestualità tecniche e di indagare l’equità dei sistemi di classificazione adottati in alcuni sport paralimpici. Riassumendo, i risultati conseguiti in questi studi hanno evidenziato che 1. L’aumento della massa muscolare rappresenta un fattore chiave nell’accumulo di minerale osseo in giovani femmine prepuberi praticanti attività sportive a carico d’impatto. 2. Nei calciatori professionisti la massa grassa, la massa magra priva di grasso e il contenuto di minerale osseo subiscono delle variazioni nel corso della stagione agonistica, in particolare a carico degli arti inferiori e a prescindere dal ruolo. 3. Il contenuto di minerale osseo e la densità minerale ossea spiegano una percentuale considerevole di variabilità della velocità della palla nel tiro della pallamano. 4. Nell’attività sportiva adattata la durata dell’infortunio influenza diversi parametri di composizione corporea degli atleti (giocatori di pallacanestro in carrozzina, giocatori di rugby in carrozzina e atleti di handbike). 5. In seguito ad una lesione midollare, sarebbe importante riprendere l’attività sportiva il prima possibile, non appena le condizioni cliniche lo consentono, per rallentare o per ridurre gli effetti negativi causati dall’evento lesivo sulla composizione corporea. 6. Dal confronto tra la tecnica plicometrica e la metodica DXA è emerso che la prima tende a sottostimare la percentuale di massa grassa in atleti praticanti sport in carrozzina sottolineando la necessità di studiare un’equazione ad hoc per questa popolazione. 7. Nei giovani giocatori di pallacanestro in carrozzina sono emerse numerose relazioni tra le variabili antropometriche e la prestazione (test da campo specifici e le statistiche degli incontri un’intera stagione competitiva). 8. Dai risultati è inoltre emersa una stretta relazione tra la tipologia e la gravità della disabilità e la prestazione nel tennis e nella pallacanestro in carrozzina, dimostrando che i vigenti sistemi di classificazione degli atleti dovrebbero essere modificati in modo da garantire lo svolgimento di competizioni eque e bilanciate.Over the course of my doctoral research project entitled “Investigating body dimension and composition across diverse populations with traditional and advanced techniques”, seven studies were conducted: “Effect of distinct impact loading sports on body composition in pre-menarcheal girls”, “Seasonal DXA-measured body composition changes in professional male soccer player”, “Bone quality predicts ball-throwing velocity in team handball”, “Body composition assessment in spinal cord injured wheelchair athletes”, “Kinematic analysis of the wheelchair tennis serve: Implications for Classification”, “Anthropometry, body composition and performance in young wheelchair basketball players”, and “Digital three-dimensional anthropometry detection of exercise-induced fat mass reduction in obese women”. Four of the above studies are published or in press in international Journals. In the above-mentioned studies, body dimensions and composition were investigated across diverse populations (e.g., pre-menarcheal gymnasts and volleyball players, elite male soccer players, sub-elite and elite handball players and wheelchair athletes) with traditional and advanced techniques. In particular, dual-energy X-ray absorptiometry (DXA) as well as manual and digital anthropometry were exploited. The combined application of traditional and advanced imaging techniques allowed me to study the anthropometry and body composition characteristics of participants in different sport activities to monitor the effects of sport training across a competitive season, analyse the relationship between anthropometry and body composition characteristics and specific technical skills, as well as provide useful information to improve the classification system of athletes playing Paralympic sports. In summary, the obtained results showed that 1. Higher muscle mass is a key factor for bone mineral accrual in pre-menarcheal girls exposed to impact-loading activity. 2. Professional soccer players undergo changes (especially in the lower limbs) in their fat mass, fat-free soft tissue mass, and bone mineral content across the season with some regional variations, irrespective of the playing position. 3. In male and female handball players, bone mineral content and/or bone mineral density is a body composition parameter able to explain a significant proportion of variability in ball throwing velocity. 4. In adapted physical activity the duration of injury strongly affect body composition of wheelchair athletes (wheelchair basketball players, wheelchair rugby players and handbikers). 5. In disabled people, it would be important to begin physical activity as soon as possible after injury in an attempt to slow or reduce the negative effects of the impairment on the body composition. 6. Comparison of current skinfold thickness predictive equation and DXA in wheelchair athletes shows a substantial underestimation of percentage of fat mass with the former, highlighting the need to use an ad hoc skinfold thickness equation for this population. 7. In young wheelchair basketball players several anthropometric variables are well correlated to wheelchair basketball performance (sport-specific field test and game-related statistics). 8. A clear relationship between the player’s impairment and performance in wheelchair tennis and in wheelchair basketball is present, suggesting that the current classification systems are to be challenged as to fairness
Are body circumferences able to predict strength, muscle mass and bone characteristics in obesity? A preliminary study in women
Full text linkMeasurement of body circumferences (BCs) is widely used as an anthropometric tool to assess body composition and health risk in obese individuals. In this preliminary work we evaluated the association of several BCs with Dual-energy X-ray Absorptiometry (DXA)-measured lean mass as well as leg press test scores with an aim at exploring the potential of BCs as predictor of body composition and muscle strength. A total of 34 female participants aged 47.3±7.6 y who were obese (BMI, 30.4-43.7 kg/m2) were recruited. The upper arm (relaxed), wrist, chest, waist, hip, thigh, and calf circumferences were measured. The skinfold-corrected muscle (including bone) circumferences at the arm, thigh, and calf site were also calculated. Lean mass components were measured by DXA with a Hologic QDR Explorer scanner according to the manufacturer's procedures. Lower limbs strength was assessed with the 1-Repetition Maximum leg press. Bivariate association between variables was assessed with the Spearman's correlation coefficient after the Benjamini and Hochberg False Discovery Rate procedure. Predictive equations were developed using stepwise multiple regression analysis. Several statistically significant correlations (Benjamini and Hochberg corrected P [Pc] < 0.05) were present between BCs and DXA-measured body composition variables, and leg press test scores with special regard to the chest, arm, waist, and hip circumferences. Multiple regression analysis yielded statistically significant predictive models (Pc < 0.05 for all; adjusted R2 ranging 0.123 - 0.504; standard error of the estimate ranging 4.0% - 11% of the mean measured value) for all body composition as well as leg press outcomes. The current findings show that BCs represent a simple, suitable anthropometric measurement with a potential to predict several lean mass components as well as lower limbs strength in obese females. The proposed predictors need to be validated in a larger sample of participants and in obese males
Differential effects of main error correction versus secondary error correction on motor pattern of running
No full textThe aim of this study was to gain a better understanding of how the run pattern varies as a consequence to main error correction versus secondary error correction. Twenty-two university students were randomly assigned to one of two training-conditions: 'main error' (ME) and 'secondary error' (SE) correction. The rear-foot strike at touchdown was hypothesized as the 'main error', whereas an incorrect shoulder position (i.e., behind the base of support) as the 'secondary error'. In order to evaluate any changes in run pattern at the foot touchdown instant, the ankle, knee and hip joint angles, the height of toe and heel (with respect to the ground), and the horizontal distance from the heel to the projected center of mass on the ground were measured. After the training-intervention, the ME group showed a significant improvement in the run pattern at the foot touchdown instant in all kinematic parameters, whereas no significant changes were found in the SE group. The results support the hypothesis that the main error can have a greater influence on the movement patterns than a secondary error. Furthermore, the findings highlight that a correct diagnosis and the correction of the 'main error' are fundamental for greater run pattern improvement
Body composition assessment in athletes with physical impairment who have been practicing a wheelchair sport regularly and for a prolonged period
No full textBACKGROUND: Today several important aspects related to the impact of long-term wheelchair sports on whole-body and regional body composition in athletes with a physical impairment are poorly understood. OBJECTIVE: This cross-sectional study aimed at investigating the impact of the long-term regular practice of wheelchair sports on body composition in male wheelchair athletes (WA) as compared with both non-athletic participants with a physical impairment and non-athletic able-bodied participants. METHODS: Nine WA were each matched pairwise by age, duration of injury and body mass index (BMI) with a participant with a physical impairment not engaged in any wheelchair sport (N-WA) and by age and BMI with an able-bodied (AB) participant. Whole-body and regional bone mineral content (BMC), fat-free soft tissue mass (FFSTM), fat mass (FM) and percentage FM (%FM) were assessed by means of Dual-Energy X-ray Absorptiometry. RESULTS: WA had significantly lower FM and %FM vs. N-WA at the whole-body level (P = 0.01 for both) and in the trunk region (P = 0.001 and P = <0.001, respectively). The only difference in body composition variables between WA and AB was found in the legs where WA had significantly higher FM (P = 0.014) along with lower BMC (P = 0.009) and FFSTM (P = 0.005) vs. AB in the legs. CONCLUSIONS: The results of the present study showed that the regular, long-term practice of wheelchair sport may be associated with beneficial body composition adaptations in athletes with a physical impairment at the whole-body and trunk level
The Muscle-Bone Unit in Male Elite Soccer Players Aged 14-19
Full text linkBackground: Muscle and bone show reciprocal interactions and are associated in a muscle-bone unit. The muscle-bone unit has been investigated to a very limited extent in soccer players. The objective of this work was to investigate in detail the muscle-bone unit in male youth elite soccer players. Methods: Bone mineral and lean mass were measured with dual-energy X-ray absorptiometry (DXA). The functional muscle-bone unit (fMBU) and the muscle-to-bone ratio (MBR) were calculated from the DXA output in a sample of players aged 14-19 (n = 193) playing in the youth squads of an Italian Serie A team. Results: Statistically significant (p < 0.05) correlations were found between lean mass variables and bone mineral content and density, also after adjusting for age, body mass, stature, maturity, and ethnicity (White/Black). fMBU and MBR were statistically significantly associated with age, body mass, stature, maturity, and ethnicity. Linear regression showed that body lean mass was the strongest predictor for bone mineral content and density. Age was a statistically significant predictor for fMBU and MBR. Playing position did not show any statistically significant relationship with bone mineral content and density, as well as fMBU or MBR. Centiles for fMBU and MBR were calculated as a reference. Conclusions: This work is the first detailed characterization of the muscle-to-bone relationship in soccer players. It is expected to be of use for sport scientists and the wide community of sportsmen and professionals involved in soccer
Physique and Performance of Young Wheelchair Basketball Players in Relation with Classification.
Full text linkThe relationships among physical characteristics, performance, and functional ability classification of younger wheelchair basketball players have been barely investigated to date. The purpose of this work was to assess anthropometry, body composition, and performance in sport-specific field tests in a national sample of Italian younger wheelchair basketball players as well as to evaluate the association of these variables with the players' functional ability classification and game-related statistics. Several anthropometric measurements were obtained for 52 out of 91 eligible players nationwide. Performance was assessed in seven sport-specific field tests (5m sprint, 20m sprint with ball, suicide, maximal pass, pass for accuracy, spot shot and lay-ups) and game-related statistics (free-throw points scored per match, two- and three-point field-goals scored per match, and their sum). Association between variables, and predictivity was assessed by correlation and regression analysis, respectively. Players were grouped into four Classes of increasing functional ability (A-D). One-way ANOVA with Bonferroni's correction for multiple comparisons was used to assess differences between Classes. Sitting height and functional ability Class especially correlated with performance outcomes, but wheelchair basketball experience and skinfolds did not. Game-related statistics and sport-specific field-test scores all showed significant correlation with each other. Upper arm circumference and/or maximal pass and lay-ups test scores were able to explain 42 to 59% of variance in game-related statistics (P<0.001). A clear difference in performance was only found for functional ability Class A and D.In younger wheelchair basketball players, sitting height positively contributes to performance. The maximal pass and lay-ups test should be carefully considered in younger wheelchair basketball training plans. Functional ability Class reflects to a limited extent the actual differences in performance
Anthropometric prediction of DXA-measured percentage of fat mass in athletes with unilateral lower limb amputation
Full text linkTo date there is no anthropometric equation specific to athletes with unilateral lower limb amputation to estimate the percentage of fat mass (%FM). This study investigated the accuracy of a set of anthropometric equations validated on able-bodied populations to predict the %FM assessed by-means of dual-energy x-ray absorptiometry (DXA) in athletes with unilateral lower limb amputation. Furthermore, a predictive anthropometric equation specific to athletes with unilateral lower limb amputation was developed from skinfold thickness measurements using DXA as the reference method for the estimation of the %FM. Twenty-nine white male athletes with unilateral lower limb amputation underwent a DXA scan and an anthropometric assessment on the same day. The %FM, calculated through several existing anthropometric equations validated upon able-bodied populations, was compared with the DXA-measured %FM (%FM_DXA). Accuracy and agreement between the two methods was computed with two-tailed paired-sample t-test, concordance correlation coefficient, reduced major axis regression and Bland-Altman analysis. A stepwise multiple regression analysis with the %FM_DXA as the dependent variable and age and nine skinfold thicknesses as potential predictors was carried out and validated using a repeated 10-fold cross-validation. A linear regression analysis with the sum of nine skinfolds as the independent variable was also carried out and validated using a repeated 10-fold cross-validation. The results showed that the anthropometric equations validated on able-bodied populations are inaccurate in the estimation of %FM_DXA with an average bias ranging from 0.51 to -13.70%. Proportional bias was also found revealing that most of the anthropometric equations considered, tended to underestimate/overestimate the %FM_DXA as body fat increased. Regression analysis produced two statistically significant models (P < 0.001 for both) which were able to predict more than 93% of total variance of %FM_DXA from the values of four skinfold measurements (i.e., thigh, abdominal, subscapular and axillary skinfold measurements) or from the sum of 9 skinfolds. Repeated cross-validation analysis highlighted a good predictive performance of the proposed equations. The predictive equations proposed in this study represent a useful tool for clinicians, nutritionists, and physical conditioners to evaluate the physical and nutritional status of athletes with unilateral lower limb amputation directly in the field
Anthropometric prediction of DXA-measured percentage of fat mass in karate athletes
No full textIn karate, high percentages of fat mass (%FM) are often associated with poor sport performance. Dual-energy X-ray absorptiometry (DXA) is able to accurately measure the %FM (%FM-DXA), but it may not be practical in some sport settings, where anthropometry has long been used as an alternative. This study aimed to explore the ability of sixteen available anthropometric equations to estimate the %FM (%FM-AE) in karate Furthermore, two population-specific predictive equations to estimate the %FM-DXA were developed from anthropometric measurements
Correction of a Technical Error in the Golf Swing: Error Amplification Versus Direct Instruction
No full textThe aim of the present study was to evaluate which of two strategies, method of amplification of error (MAE) or direct instruction (DI), would benefit error correction more during a full swing with a driver. Thirty-four golfers were randomly assigned to one of three training conditions (MAE, DI and Control). Participants were tested in two sessions: a practice session in which each golfer performed 7 pre-training trials (T0), 6 training-intervention trials, and 7 post-training trials (T1); a retention test session (T2) after one week. A 3x3 experimental design was used: training condition - MAE, DI, Control; and Time - T0, T1, T2. Results showed that MAE is more effective in correcting the technical errors than the DI and that the benefits derived from its application are still present in the retention test. These findings revealed that MAE is an effective method for rapidly improving motor performance in a complex skill
Effect of different impact loading sports on bone quality and body composition in pre-pubertal girls
No full textAdaptations of bone to exercise are dependent in part on the magnitude and type of loading stimulus and the timing of the loading exposure across the life cycle. Women's artistic gymnastics and volleyball are Olympic disciplines practiced by millions worldwide, which are characterized by high impact loading (3-6 times the body weight) and muscle strength requirement. The aim of this study was to compare the effect of different impact loading sports on bone quality and body composition of pre-menarcheal girls. A total of 30 pre-pre-menarcheal athletes (aged 11.1±1.33[SD]y) participating in volleyball (n=10) and artistic gymnastics at high (HGYM, n=10) and low (LGYM, n=10) intensity training underwent total body DXA analysis. Output measurements were bone mineral content (BMC), areal bone mineral density (aBMD), fat free soft tissue mass (FFST), fat mass (FM), and percentage FM at the total body and regional level (arms, legs and trunk) as well as specific axial skeleton sites (thoracic and lumbar spine, pelvis). After adjusting for body size, total body composition measurements were all significantly (p<0.01) different in the three groups of pre- pubertal athletes. VOLLEY showed lower BMC and FFST, and greater FM and %FM vs. both HGYM and LGYM. The main difference between LGYM and HGYM was greater %FM in the former. Similar results were found at the regional level (but for similar BMC in the legs) and at lumbar spine and pelvis. Linear regression analysis showed that a model using FFST mass the as independent variable is able to explain more than 90% of variance in total body less head BMC in the whole group of impact loading athletes, whereas introducing %FM in the model did not improve it predictive power at all. The findings of this study provide evidence that greater bone mineral accrual takes place in pre-menarcheal impact loading athletes participating in artistic gymnastics vs. volleyball and the dose of impact loading activity mainly affect %FM; moreover, results suggest that BMC in the weight-bearing skeleton is strongly affected by FFST
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