Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nutrients ; 13(7)2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34371824

RESUMO

Delayed-onset muscle soreness (DOMS) is associated with increases in acute inflammatory and biochemical markers, muscle swelling, pain, and reduced functional performance. This study aimed to investigate the preventative effects of crocodile blood supplementation on DOMS induced by eccentric exercise. Sixteen healthy males were randomly allocated to either a crocodile blood (CB, n = 8) or a placebo (PL, n = 8) treatment. Participants receiving the CB treatment consumed four capsules of freeze-dried CB powder (1 g day-1) over 18 days. Participants receiving the other treatment were administered a placebo over the same period. An eccentric exercise protocol was performed, and functional performance, visual analogue scale (VAS)-measured pain, knee range of movement (ROM), thigh circumference (swelling), and cytokines, enzymes, and biochemical parameters were assessed immediately after exercise as well as after 24 h, 48 h, and 72 h. CB supplementation could significantly maintain maximum voluntary isometric contraction (MVIC) at 24 h (p = 0.001) and 48 h after exercise (p = 0.001) when comparing values at different times for the CB group. In the CB group, thigh circumference decreased only immediately after eccentric exercise (p = 0.031) in comparison with pre-eccentric exercise values. An 18-day supplementation (1 g day-1) of crocodile blood does aid in the maintenance of functional performance and muscle swelling after eccentric exercise. Our data indicate that 1 g day-1 of crocodile blood supplementation should be safe for human consumption.


Assuntos
Jacarés e Crocodilos/sangue , Suplementos Nutricionais , Exercício Físico/fisiologia , Doenças Musculares/prevenção & controle , Mialgia/prevenção & controle , Animais , Biomarcadores/análise , Método Duplo-Cego , Edema/etiologia , Edema/fisiopatologia , Edema/prevenção & controle , Voluntários Saudáveis , Humanos , Contração Isométrica/efeitos dos fármacos , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiopatologia , Doenças Musculares/etiologia , Doenças Musculares/fisiopatologia , Mialgia/etiologia , Mialgia/fisiopatologia , Medição da Dor , Desempenho Físico Funcional , Amplitude de Movimento Articular/efeitos dos fármacos , Adulto Jovem
2.
Int J Sport Nutr Exerc Metab ; 26(3): 259-67, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24458265

RESUMO

PURPOSE: The implications of undertaking DXA scans using best practice protocols (subjects fasted and rested) or a less precise but more practical protocol in assessing chronic changes in body composition following training and a specialized recovery technique were investigated. METHODS: Twenty-one male cyclists completed an overload training program, in which they were randomized to four sessions per week of either cold water immersion therapy or control groups. Whole-body DXA scans were undertaken with best practice protocol (Best) or random activity protocol (Random) at baseline, after 3 weeks of overload training, and after a 2-week taper. Magnitudes of changes in total, lean and fat mass from baseline-overload, overload-taper and baseline-taper were assessed by standardization (Δmean/SD). RESULTS: The standard deviations of change scores for total and fat-free soft tissue mass (FFST) from Random scans (2-3%) were approximately double those observed in the Best (1-2%), owing to extra random errors associated with Random scans at baseline. There was little difference in change scores for fat mass. The effect of cold water immersion therapy on baseline-taper changes in FFST was possibly harmful (-0.7%; 90% confidence limits ±1.2%) with Best scans but unclear with Random scans (0.9%; ±2.0%). Both protocols gave similar possibly harmful effects of cold water immersion therapy on changes in fat mass (6.9%; ±13.5% and 5.5%; ±14.3%, respectively). CONCLUSIONS: An interesting effect of cold water immersion therapy on training-induced changes in body composition might have been missed with a less precise scanning protocol. DXA scans should be undertaken with Best.


Assuntos
Absorciometria de Fóton , Atletas , Composição Corporal , Ciclismo , Índice de Massa Corporal , Temperatura Baixa , Humanos , Masculino , Adulto Jovem
3.
J Clin Densitom ; 19(3): 282-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26343822

RESUMO

Dual-energy X-ray absorptiometry (DXA) is an accepted time-efficient method of body composition assessment for total body and regional fat mass (FM), lean mass (LM), and bone mineral content (BMC), but for longitudinal monitoring the measurements must be sufficiently reliable. The aim of this study was to compare the reliability of a new positioning protocol (Nana et al) with the current reference (National Health and Nutrition Examination Survey [NHANES]) protocol and investigate their within-protocol precision. Thirty healthy adults (16 females and 14 males) underwent 4 whole-body DXA scans in succession with full repositioning between scans. The scan order was randomized, with 2 scans undertaken in accordance with the current NHANES protocol and 2 using the Nana et al protocol. Magnitudes of typical errors of measurement and changes in the mean of DXA body composition estimates were assessed as standardized effect sizes. The Nana et al protocol repositioning produced trivial typical errors for total body across all LM estimates except for FM in the arms and trunk which were moderately substantial. The NHANES protocol produced similar typical errors for all measurements in LM except for FM and BMC in the trunk and arms which were substantially larger than the smallest worthwhile effect. The difference between protocols produced substantially large typical errors in estimations of both total body FM and regional FM and BMC, but differences in LM were all less than the smallest worthwhile effect. Although both protocols demonstrated acceptable intratest reliability, the Nana et al protocol produced enhanced precision in regional (arms and trunk) FM and BMC. The protocols were substantially different in body composition assessment especially for FM and thus should not to be interchanged. Anecdotally, subjects felt more comfortable and supported during the scan with the Nana et al protocol.


Assuntos
Absorciometria de Fóton/métodos , Tecido Adiposo/diagnóstico por imagem , Composição Corporal , Posicionamento do Paciente/métodos , Adulto , Densidade Óssea , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Imagem Corporal Total , Adulto Jovem
4.
PLoS One ; 10(5): e0123302, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25970439

RESUMO

Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this. PURPOSE: To examine whether a calcium-rich pre-exercise meal attenuates exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses. METHODS: Using a randomized, counterbalanced crossover design, 32 well-trained female cyclists completed two 90 min cycling trials separated by 1 day. Exercise trials were preceded 2 hours by either a calcium-rich (1352 ± 53 mg calcium) dairy based meal (CAL) or a control meal (CON; 46 ± 7 mg calcium). Blood was sampled pre-trial; pre-exercise; and immediately, 40 min, 100 min and 190 min post-exercise. Blood was analysed for ionized calcium and biomarkers of bone resorption (Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP)) using the established enzyme-linked immunosorbent assay technique. RESULTS: PTH and CTX-I increased from pre-exercise to post-exercise in both conditions but was attenuated in CAL (p < 0.001). PTH was 1.55 [1.20, 2.01] times lower in CAL immediately post-exercise and 1.45 [1.12, 1.88] times lower at 40 min post-exercise. CTX-I was 1.40 [1.15, 1.70] times lower in CAL at immediately post-exercise, 1.30 [1.07, 1.57] times lower at 40 min post-exercise and 1.22 [1.00, 1.48] times lower at 190 min post-exercise (p < 0.05). There was no significant interaction between pre-exercise meal condition and time point for CTX-II (p = 0.732) or PINP (p = 0.819). CONCLUSION: This study showed that a calcium-rich pre-exercise breakfast meal containing ~1350 mg of calcium consumed ~90 min before a prolonged and high intensity bout of stationary cycling attenuates the exercise induced rise in markers of bone resorption--PTH and CTX-I. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12614000675628.


Assuntos
Atletas , Ciclismo , Reabsorção Óssea/prevenção & controle , Cálcio na Dieta/administração & dosagem , Cálcio/sangue , Adolescente , Adulto , Biomarcadores/sangue , Reabsorção Óssea/sangue , Reabsorção Óssea/dietoterapia , Cátions Bivalentes , Colágeno Tipo I/sangue , Colágeno Tipo II/sangue , Estudos Cross-Over , Dieta , Exercício Físico , Feminino , Humanos , Hormônio Paratireóideo/sangue , Fragmentos de Peptídeos/sangue , Peptídeos/sangue , Resistência Física , Pró-Colágeno/sangue , Sudorese/fisiologia
5.
Int J Sport Nutr Exerc Metab ; 25(2): 198-215, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25029265

RESUMO

Dual energy X-ray absorptiometry (DXA) is rapidly becoming more accessible and popular as a technique to monitor body composition, especially in athletic populations. Although studies in sedentary populations have investigated the validity of DXA assessment of body composition, few studies have examined the issues of reliability in athletic populations and most studies which involve DXA measurements of body composition provide little information on their scanning protocols. This review presents a summary of the sources of error and variability in the measurement of body composition by DXA, and develops a theoretical model of best practice to standardize the conduct and analysis of a DXA scan. Components of this protocol include standardization of subject presentation (subjects rested, overnight-fasted and in minimal clothing) and positioning on the scanning bed (centrally aligned in a standard position using custom-made positioning aids) as well as manipulation of the automatic segmentation of regional areas of the scan results. Body composition assessment implemented with such protocol ensures a high level of precision, while still being practical in an athletic setting. This ensures that any small changes in body composition are confidently detected and correctly interpreted. The reporting requirements for studies involving DXA scans of body composition include details of the DXA machine and software, subject presentation and positioning protocols, and analysis protocols.


Assuntos
Atletas , Composição Corporal , Exercício Físico , Modelos Biológicos , Esportes , Absorciometria de Fóton/métodos , Humanos , Reprodutibilidade dos Testes
6.
Int J Sport Nutr Exerc Metab ; 24(5): 553-8, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25029702

RESUMO

Some athletes avoid dairy in the meal consumed before exercise due to fears about gastrointestinal discomfort. Regular exclusion of dairy foods may unnecessarily reduce intake of high quality proteins and calcium with possible implications for body composition and bone health. This study compared the effects of meals that included (Dairy) or excluded (Control) dairy foods on gastric comfort and subsequent cycling performance. Well-trained female cyclists (n = 32; mean ± SD; 24.3 ± 4.1 y; VO(2peak) 57.1 ± 4.9 ml/kg/min) completed two trials (randomized cross-over design) in which they consumed a meal (2 g/kg carbohydrate and 54 kJ/kg) 2 hr before a 90-min cycle session (80 min at 60% maximal aerobic power followed by a 10-min time trial; TT). The dairy meal contained 3 servings of dairy foods providing ~1350 mg calcium. Gut comfort and palatability were measured using questionnaires. Performance was measured as maximum mean power during the TT (MMP10(min)). There was no statistical or clinical evidence of an effect of meal type on MMP10(min) with a mean difference (Dairy - Control) of 4 W (95% CI [-2, 9]). There was no evidence of an association between pretrial gut comfort and meal type (p = .15) or between gut comfort delta scores and meal type postmeal (p = .31), preexercise (p = .17) or postexercise (p = .80). There was no statistical or clinical evidence of a difference in palatability between meal types. In summary, substantial amounts of dairy foods can be included in meals consumed before strenuous cycling without impairing either gut comfort or performance.


Assuntos
Dor Abdominal , Ciclismo , Laticínios , Dieta , Exercício Físico , Refeições , Resistência Física , Dor Abdominal/etiologia , Adulto , Laticínios/efeitos adversos , Feminino , Humanos , Esforço Físico , Inquéritos e Questionários , Paladar , Adulto Jovem
7.
Med Sci Sports Exerc ; 45(1): 178-85, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22895377

RESUMO

PURPOSE: Dual-energy x-ray absorptiometry (DXA) is rapidly becoming more accessible and popular as a technique to monitor body composition, especially in athletic populations. This study investigates the reliability of DXA in measuring body composition of active individuals, specifically to ascertain biological variability associated with two different types of exercise under free-living conditions in active individuals. METHODS: Well-trained individuals (27 strength-trained male subjects, 14 female cyclists, and 14 male cyclists) underwent three whole-body DXA scans over a 1-d period: in the morning after an overnight fast, approximately 5 min later after repositioning on the scanning bed, and shortly after a self-chosen exercise session (resistance training or cycling). Subjects were allowed to consume food and fluid ad libitum before and during exercise as per their usual practices. Magnitude of typical (standard) errors of measurement and changes in the mean of DXA measures were assessed by standardization. RESULTS: Exercise and its related practices of fluid and food intake are associated with changes in the mean estimates of total and regional body composition that range from trivial to small but substantial. An exercise session also increases the typical error of measurement of these characteristics by approximately 10%. CONCLUSION: The easiest and most practical way to minimize the biological "noise" associated with undertaking a DXA scan is to have subjects fasted and rested before measurement. Until sufficient data on the smallest important effect are available, both biological and technical "noises" should be minimized so that any small but potentially "real" changes can be confidently detected.


Assuntos
Absorciometria de Fóton , Atletas , Ciclismo/fisiologia , Composição Corporal/fisiologia , Treinamento de Força , Absorciometria de Fóton/normas , Adiposidade/fisiologia , Adulto , Densidade Óssea/fisiologia , Ingestão de Líquidos/fisiologia , Ingestão de Alimentos/fisiologia , Exercício Físico/fisiologia , Feminino , Humanos , Modelos Lineares , Masculino , Reprodutibilidade dos Testes , Fatores Sexuais
8.
Int J Sport Nutr Exerc Metab ; 22(5): 313-22, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23011648

RESUMO

Dual-energy X-ray absorptiometry (DXA) is becoming a popular tool to measure body composition, owing to its ease of operation and comprehensive analysis. However, some people, especially athletes, are taller and/or broader than the active scanning area of the DXA bed and must be scanned in sections. The aim of this study was to investigate the reliability of DXA measures of whole-body composition summed from 2 or 3 partial scans. Physically active young adults (15 women, 15 men) underwent 1 whole-body and 4 partial DXA scans in a single testing session under standardized conditions. The partial scanning areas were head, whole body from the bottom of the chin down, and right and left sides of the body. Body-composition estimates from whole body were compared with estimates from summed partial scans to simulate different techniques to accommodate tall and/or broad subjects relative to the whole-body scan. Magnitudes of differences in the estimates were assessed by standardization. In simulating tall subjects, summation of partial scans that included the head scan overestimated whole-body composition by ~3 kg of lean mass and ~1 kg of fat mass, with substantial technical error of measurement. In simulating broad subjects, summation of right and left body scans produced no substantial differences in body composition than those of the whole-body scan. Summing partial DXA scans provides accurate body-composition estimates for broad subjects, but other strategies are needed to accommodate tall subjects.


Assuntos
Absorciometria de Fóton , Reprodutibilidade dos Testes , Atletas , Composição Corporal , Humanos
9.
Med Sci Sports Exerc ; 44(1): 180-9, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22179140

RESUMO

PURPOSE: Dual-energy x-ray absorptiometry (DXA) is becoming a popular tool to measure body composition in athletes, owing to its ease of operation and comprehensive analysis of body composition. This study represents the first systematic investigation of the reliability of DXA measurements of body composition in trained individuals and includes measurements of daily variability as well as the specific effect of the intake of a meal. METHODS: Physically active young adults (15 females, 16 males) underwent five whole-body DXA scans during a 2-d period: in the morning after an overnight fast, ~5 min later after repositioning on the scanning bed, ~8 h later after usual daily activities, and the next morning before and ~30 min after consumption of a simple breakfast. Magnitudes of typical (standard) errors of measurement and changes in the mean of DXA measures were assessed by standardization. RESULTS: Repositioning produced trivial typical errors for whole-body composition, whereas regional body composition showed substantial errors. Daily activities and consumption of breakfast generally produced a substantial increase in the typical error and mean of DXA estimates of total and regional lean mass and associated body mass. CONCLUSIONS: Having a standardized scanning protocol and fasted subjects is the most practical way to minimize measurement errors. Future studies involving DXA in measuring body composition should report their scanning and analysis protocol with their associated typical errors of measurement so that the level of reliability can be assessed.


Assuntos
Absorciometria de Fóton/normas , Atividades Cotidianas , Composição Corporal , Absorciometria de Fóton/métodos , Adulto , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...