RESUMO
Syed-Abdul, MM, Soni, DS, Miller, WM, Johnson, RJ, Barnes, JT, Pujol, TJ, and Wagganer, JD. Traditional versus suspended push-up muscle activation in athletes and sedentary women. J Strength Cond Res 32(7): 1816-1820, 2018-Many strength training programs incorporate push-up exercises, which primarily activate upper-body muscles. Past data support the fact that shoulder girdle muscles (i.e., triceps (T) and anterior deltoids [AD]) exhibit greater electromyography (EMG) activity when a push-up is performed on an unstable (i.e., suspended [SP]) vs. stable (i.e., traditional [TD]) surface (). Sixty-nine healthy female volunteers (soccer players [SO], n = 24; gymnasts [GY], n = 21; sedentary [SE], n = 24) performed three TD and three SP push-ups. Muscle activation, expressed as absolute integral (mV), was measured using EMG analysis. Significant increases in muscle activation were exhibited by GY (TD: p < 0.01 and SP: p < 0.001) and SO (TD: p < 0.05 and SP: p < 0.05) compared to SE for the T muscle. Only SO (p < 0.05) exhibited significantly higher muscle activation during the SP versus TD. For the AD, values were significantly higher for SO (TD: p < 0.001 and SP: p < 0.001) and GY (TD: p < 0.01 and SP: p < 0.01) compared to the SE group. In addition, significantly higher values were exhibited by SO compared with GY during TD push-ups (p < 0.01). Both the SO (p < 0.05) and GY (p < 0.05) group exhibited significantly higher values during SP versus TD push-ups. Finally, values were significantly higher for the AD compared to the T muscle only in the SO group during TD (p < 0.01) and SP (p < 0.05) push-ups. Data from this study for trained women (i.e., SO) are consistent with previous studies, whereas for untrained women (i.e., SE) the findings differed during TD and SP push-ups for both muscles. Differences were also observed between female SO and GY are unexplainable and therefore need further investigation.
Assuntos
Ginástica/fisiologia , Músculo Esquelético/fisiologia , Treinamento Resistido/métodos , Comportamento Sedentário , Futebol/fisiologia , Adolescente , Braço , Músculo Deltoide/fisiologia , Eletromiografia , Exercício Físico/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Ombro , Adulto JovemRESUMO
UNLABELLED: The Åstrand-Ryhming Submaximal Bicycle Test is an accurate and widely used test to estimate maximal oxygen consumption. This test requires a participant to maintain a workload over a 6-min. PERIOD: The issue facing many employing this protocol is the identification of an appropriate workload for the cycling regimen. The present study is designed to identify a method for determining an appropriate workload for female participants. A prior study designed a workload selection procedure specifically for men; however, the selection procedure designed for women in this study was better able to elicit a final heart rate (average of minutes five and six) between 165-170 bpm compared to the original Åstrand-Ryhming procedure.
Assuntos
Ciclismo/fisiologia , Teste de Esforço/métodos , Consumo de Oxigênio/fisiologia , Carga de Trabalho , Adolescente , Adulto , Feminino , Humanos , Adulto JovemRESUMO
The aim of this investigation was to determine the validity of a portable ultrasound instrument for estimating adipose tissue (AT%) compared to dual-energy X-ray absorptiometry (DXA) in female collegiate gymnasts. Participants had their measurements taken in the following order: urine-specific gravity, body mass, height, ultrasound determined AT% (1-site and 3-site) and DXA determined AT%. The current pilot study found significant differences between estimates of AT% (P < 0·001). Pearson's correlations between DXA and 1-site and 3-site estimates were r = 0·786 and r = 0·753, respectively. The standard error of the estimate between DXA and 1-site and 3-site estimates was 3·6% and 3·9%, respectively. However, the average deviation of individual scores from the line of identity was 6·7% for the 1-site and 4·9% for the 3-site, when compared with the DXA estimate. The results of this preliminary study found that the portable ultrasound was not a valid estimate of AT% when compared with the DXA estimate in female collegiate gymnasts.
Assuntos
Tecido Adiposo/diagnóstico por imagem , Adiposidade , Ginástica , Ultrassonografia/instrumentação , Absorciometria de Fóton , Desenho de Equipamento , Feminino , Humanos , Projetos Piloto , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Adulto JovemRESUMO
When health professionals measure the fitness levels of clients, body composition is usually estimated. In field settings, body composition is commonly estimated with skinfolds or bioelectrical impedance analysis. Recently, a portable ultrasound device has been manufactured to estimate what percentage of body mass is composed of adipose tissue (AT%). A reported advantage of using ultrasound is that inter- and intrarater variations may be minimized when compared with the skinfold technique. Therefore, the purpose of this pilot study was twofold; 1) to determine the validity of a portable ultrasound device compared with skinfolds and 2) determine the reliability of the portable ultrasound device. Participants had their measurements taken in the following order: urine specific gravity, body mass, height, skinfolds and ultrasound determined. Participants had their urine specific gravity and ultrasound determined AT% estimates measured again 48 h later. The current pilot study found that the ultrasound was not a valid estimate of AT% when compared with the skinfold estimate (TE > 4%). In addition, the 1-site estimate from the ultrasound was more reliable than the 3-site estimate of AT%. These data are of importance to practitioners because it demonstrates that while the ultrasound is not a valid estimate compared with skinfolds, the 1-site estimate may be able to track changes in AT% over time, making the ultrasound an option for assessing changes in body composition.
Assuntos
Tecido Adiposo/diagnóstico por imagem , Adiposidade , Adulto , Estatura , Peso Corporal , Desenho de Equipamento , Feminino , Humanos , Masculino , Projetos Piloto , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Dobras Cutâneas , Ultrassonografia , Urinálise , Adulto JovemRESUMO
Hypertension is a risk factor for heart disease, and chronic exercise is recognized as a method for reducing resting blood pressure. Recent studies report that while exercise may benefit the majority of the population, the blood pressure adaptation is not always uniform; some individuals have an adverse blood pressure response to chronic aerobic exercise programmes. The purpose of this study was to examine the individual changes in resting blood pressure in response to exercise training regimens aimed at increasing muscle mass and strength. We have also included exercise (resistance and aerobic) in combination with blood flow restriction (BFR). Of 74 individuals, 11% had an increased risk, 16% had a decreased risk and 73% had no change in risk classification following exercise. The statistical analysis found that the group that decreased risk with exercise tended to have higher baseline levels of blood pressure. However, there were little baseline differences between the group that increased risk or the group that had no change in risk, suggesting that starting values may not necessarily determine who will see a beneficial response. In conclusion, the blood pressure adaptation to resistance training and exercise with BFR is not homogeneous with some participants increasing, decreasing or staying in the same risk category following an exercise intervention. These are important findings as they would not have been noted or discussed when looking only at the group means. Future research may identify molecular predictors so that individuals at risk for adverse events can be identified prior to exercise.
Assuntos
Pressão Sanguínea , Exercício Físico , Hipertensão/fisiopatologia , Adaptação Fisiológica , Adulto , Idoso , Feminino , Humanos , Hipertensão/diagnóstico , Hipertensão/etiologia , Hipertensão/prevenção & controle , Masculino , Pessoa de Meia-Idade , Contração Muscular , Força Muscular , Músculo Esquelético/fisiologia , Estudos Retrospectivos , Fatores de Risco , Adulto JovemRESUMO
When assessing the fitness levels of athletes, body composition is usually estimated, as it may play a role in athletic performance. Therefore, the purpose of this study was to determine the validity of bioelectrical impedance analysis (BIA) and skinfold (SKF) methods compared with dual-energy X-ray absorptiometry (DXA) for estimating percent body fat (%BF) in Division 1 collegiate baseball players (n = 35). The results of this study indicate that the field methods investigated were not valid compared with DXA for estimating %BF. In conclusion, this study does not support the use of the TBF-350, HBF-306, HBF-500, or SKF thickness for estimating %BF in collegiate baseball players. The reliability of these BIA devices remains unknown; therefore, it is currently uncertain if they may be used to track changes over time.
Assuntos
Tecido Adiposo/fisiologia , Beisebol , Composição Corporal/fisiologia , Esportes/fisiologia , Absorciometria de Fóton/métodos , Adolescente , Impedância Elétrica , Humanos , Masculino , Reprodutibilidade dos Testes , Dobras Cutâneas , Adulto JovemRESUMO
PURPOSE: When assessing fitness levels, body composition is usually measured. The purpose of this study was to determine the overall efficacy of a body mass index (BMI) equation for predicting body composition with respect to college aged participants. METHODS: Body composition was measured using dual-energy x-ray absorptiometry (DXA) and was estimated using the Womersley and Durnin BMI prediction equation. RESULTS: There was no significant (P=0.8) percent body fat (%BF) difference between the BMI prediction equation and DXA (BMI Predicted=25 (10) [min=6; max=52] %BF vs DXA=25 (6) [min=10; max=45] %BF). In addition, a significant correlation was found between the two approaches (r=0.791, P=0.001). However, both the standard error of estimate (6.32 %BF) and total error (6.63 %BF) were outside acceptable ranges for prediction equations. CONCLUSION: The Womersley and Durnin equation for estimating %BF was not found to be a good estimate. Therefore, although the BMI predicted %BF has been previously found to predict skinfold estimated %BF, it does not appear valid in estimating %BF from DXA.
RESUMO
When health professionals measure the fitness levels of clients, body composition is usually estimated. In practice, the reliability of the measurement may be more important than the actual validity, as reliability determines how much change is needed to be considered meaningful. Therefore, the purpose of this study was to determine the reliability of two bioelectrical impedance analysis (BIA) devices (in athlete and non-athlete mode) and compare that to 3-site skinfold (SKF) readings. Twenty-one college students attended the laboratory on two occasions and had their measurements taken in the following order: body mass, height, SKF, Tanita body fat-350 (BF-350) and Omron HBF-306C. There were no significant pairwise differences between Visit 1 and Visit 2 for any of the estimates (P>0.05). The Pearson product correlations ranged from r = 0.933 for HBF-350 in the athlete mode (A) to r = 0.994 for SKF. The ICC's ranged from 0.93 for HBF-350(A) to 0.992 for SKF, and the MD's ranged from 1.8% for SKF to 5.1% for BF-350(A). The current study found that SKF and HBF-306C(A) were the most reliable (<2%) methods of estimating BF%, with the other methods (BF-350, BF-350(A), HBF-306C) producing minimal differences greater than 2%. In conclusion, the SKF method presented with the best reliability because of its low minimal difference, suggesting this method may be the best field method to track changes over time if you have an experienced tester. However, if technical error is a concern, the practitioner may use the HBF-306C(A) because it had a minimal difference value comparable to SKF.
Assuntos
Adiposidade , Antropometria , Antropometria/instrumentação , Antropometria/métodos , Impedância Elétrica , Desenho de Equipamento , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Dobras Cutâneas , Adulto JovemRESUMO
PURPOSE: The purpose of this investigation was to compare a practical measurement of fat free mass index (FFMI) from bioelectrical impedance analysis (BIA) to the dual energy X-ray absorptiometry (DEXA) value in collegiate athletes. METHODS: Thirty-three male baseball players and 16 female gymnasts volunteered to participate in this study during their respective pre-season. Subjects visited the laboratory once and had their measurements taken in the following order: weight, height, DEXA, and Omron HBF-500. RESULTS: The BIA device investigated was not a valid estimate of FFMI when compared to the DEXA. The TE was 0.93 kg/ m(2) for males and 0.78 kg/ m(2) for females. There were also significant mean differences between the BIA prediction and the DEXA value for males (BIA=20.6 kg/m(2) vs. DEXA=21.1 kg/m(2), P=0.007) and females (BIA=16.2 kg/m(2) vs. DEXA=17.5 kg/m(2), P=0.001). CONCLUSIONS: The BIA device investigated in this study did not provide a valid estimate of FFMI in male and female collegiate athletes. Although there was a general tendency for the BIA to underestimate FFMI compared to DEXA, 98% of the estimates were within plus or minus 2 kg/ m(2). Therefore, while slightly biased, BIA may provide a reasonable (± 2 kg/ m(2)) estimate of nutritional status for practitioners who are unable able to afford more expensive equipment.
RESUMO
OBJECTIVES: Exercise to failure results in similar muscle protein synthesis responses, independent of intensity. However, low-intensity exercise likely requires more time under tension and those with injuries may be incapable of sustaining the mechanical stress to reach failure. DESIGN: The purpose was to determine whether elastic knee wraps (KW) provide a stimulus to decrease time under tension and overall volume of work while maintaining a similar level of metabolic stress. METHODS: Thirteen healthy subjects participated in a randomized crossover study consisting of three trials. The first determined 1 repetition maximum (1RM) on the bilateral leg extension. Subjects were then assigned to a blood flow restriction (BFR) or control (CON) group. After trial 2, subjects crossed over to the opposite trial. KW were placed around the thigh of each leg during BFR. Leg extensions were completed at 30% 1RM until failure. Whole blood lactate (WBL) was taken pre-, post-, and 3 and 5 min postexercise. Heart rate (HR) was measured before, following the first and second sets, and 3 and 5 min postexercise. RESULTS: This study found KW provide a BFR stimulus allowing failure to occur sooner with similar metabolic stress postreperfusion. There were no differences in HR at any time point. CONCLUSIONS: These results may benefit populations that cannot sustain the mechanical stress of high-intensity exercise or low-intensity exercise that requires a longer sustained time under tension.
Assuntos
Isquemia/fisiopatologia , Contração Muscular , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/fisiopatologia , Treinamento Resistido/métodos , Adulto , Análise de Variância , Fenômenos Biomecânicos , Estudos Cross-Over , Metabolismo Energético , Feminino , Frequência Cardíaca , Humanos , Isquemia/metabolismo , Joelho , Masculino , Fadiga Muscular , Músculo Esquelético/metabolismo , Oklahoma , Fluxo Sanguíneo Regional , Estresse Mecânico , Fatores de Tempo , Adulto JovemRESUMO
Dietary protein intake and specifically the quality of the protein in the diet has become an area of recent interest. This study determined the relationship between the amount of quality protein, carbohydrate, and dietary fat consumed and the amount of times the ~10 g essential amino acid (EAA) threshold was reached at a meal, with percent central abdominal fat (CAF). Quality protein was defined as the ratio of EAA to total dietary protein. Quality protein consumed in a 24-hour period and the amount of times reaching the EAA threshold per day was inversely related to percent CAF, but not for carbohydrate or dietary fat. In conclusion, moderate to strong correlations between variables indicate that quality and distribution of protein may play an important role in regulating CAF, which is a strong independent marker for disease and mortality.
RESUMO
The American College of Sports Medicine recommends lifting a weight of at least 70% of one's concentric one repetition maximum to achieve muscular hypertrophy as it is believed that anything below this intensity does not produce significant muscle growth. Recent studies have found muscle hypertrophy to occur with low-intensity 'aerobic-like' exercise with the application of blood flow restriction (BFR) to the limbs. Previous research with low load resistance training has shown that elastic knee wraps provide a practical means to induce elevations in whole blood lactate (WBL), which has been hypothesized to result in many of the adaptations observed with this type of exercise. However, this has yet to be investigated with low-intensity walking. Thus, the purpose of this paper was to determine the degree to which WBL increases with practical BFR walking. Exercise consisted of five 2-min bouts of walking at 75 m per min on a motor-driven treadmill with a 1-min rest period following each exercise bout. Participants completed the walking with (BFR) and without [control (CON)] restriction to the upper thigh in a randomized order. Practical BFR with elastic knee wraps did statistically increase WBL compared with CON; however, this was not considered a real change because the minimal difference between conditions was not exceeded. In conclusion, metabolic stress is not increased following practical BFR walking exercise. This study may provide an explanation for the lower hormone response observed with BFR walking and provide further evidence that mechanisms other than metabolic accumulation exist with BFR.
Assuntos
Exercício Físico , Ácido Láctico/sangue , Músculo Esquelético/irrigação sanguínea , Caminhada , Análise de Variância , Biomarcadores/sangue , Bandagens Compressivas , Estudos Cross-Over , Feminino , Humanos , Extremidade Inferior , Masculino , Fluxo Sanguíneo Regional , Fatores de Tempo , Adulto JovemRESUMO
Historically, collegiate wrestlers have been associated with utilizing rapid weight loss methods to reach a desired weight class. Following three deaths in 1997, the National Collegiate Athletic Association (NCAA) implemented a program which prevents wrestlers from wrestling below a minimum weight (MW) of 5% body fat. Although numerous studies have investigated adolescent wrestlers, few have investigated collegiate wrestlers using the methods outlined by the NCAA. The purpose of this review paper is to outline potential problems with the current NCAA protocol as well as critique studies investigating the validity of methods to assess MW.
Assuntos
Peso Corporal , Guias como Assunto , Reprodutibilidade dos Testes , Esportes , Tecido Adiposo , Adolescente , Composição Corporal , Humanos , Masculino , Estudos de Validação como Assunto , Luta RomanaRESUMO
BACKGROUND: Quality protein intake, and distribution of that protein, could play an important role with lean mass (LM), bone mineral density (BMD) and bone mineral content (BMC). Research has demonstrated that muscle protein synthesis is maximally stimulated at approximately 10 g of essential amino acids (EAA)/meal. This study sought to determine the relationship between the amount of quality protein consumed and the amount of times the approximately 10 g EAA threshold was reached at a meal, with respect to LM, BMD and BMC. METHODS: Twenty-seven subjects participated in this study. EAA intake was determined from a 3-day food record, and amino acid profiling was determined using a computer program (USDA Database, release 22). LM, BMD and BMC were measured using dual-energy X-ray absorptiometry. Quality protein was defined as the ratio of EAA to total dietary protein. Data were analyzed using Pearson partial coefficient correlations, controlling for body mass, with an α-level of 0.05. RESULTS: Quality protein consumed in a 24-hour period and the amount of times reaching the EAA threshold per day was positively associated with LM, BMD and BMC, and had an inverse relationship with body fat percentage. CONCLUSION: Both quality protein intake and frequency are positively associated with favorable body composition and bone health.
Assuntos
Aminoácidos Essenciais/administração & dosagem , Osso e Ossos/metabolismo , Proteínas Alimentares/administração & dosagem , Proteínas Musculares/biossíntese , Músculo Esquelético/metabolismo , Aminoácidos Essenciais/metabolismo , Aminoácidos Essenciais/normas , Composição Corporal/efeitos dos fármacos , Composição Corporal/fisiologia , Densidade Óssea/efeitos dos fármacos , Densidade Óssea/fisiologia , Proteínas Alimentares/metabolismo , Proteínas Alimentares/normas , HumanosRESUMO
Training at low intensities with moderate vascular occlusion results in increased muscle hypertrophy, strength, and endurance. Elastic knee wraps, applied to the proximal portion of the target muscle, might elicit a stimulus similar to the KAATSU Master Apparatus. The purpose of this study was to test the hypothesis that intermittently occluding the leg extensors with elastic knee wraps would increase whole-blood lactate (WBL) over control (CON). Twelve healthy men and women participated in this study (age 21.2 ± 0.35 years, height 168.9 ± 2.60 cm, and body mass 71.2 ± 4.16 kg). One repetition maximum (1RM) testing for the leg extensors was performed on a leg extension machine for the first trial, followed by occlusion (OCC) and CON trials. Four sets of leg extension exercise (30-15-15-15) were completed with 150-second rest between sets at 30% 1RM. Whole-blood lactate, heart rate (HR), and ratings of perceived exertion (RPEs) were measured after every set of exercise and 3 minutes postexercise. Data were analyzed using repeated-measures analysis of variance with statistical significance set at p ≤ 0.05. Whole-blood lactate increased in response to exercise (p = 0.01) but was not different between groups (OCC 6.28 ± 0.66 vs. CON 5.35 ± 0.36 mmol·L, p = 0.051). Heart rate (OCC 128.86 ± 4.37 vs. CON 119.72 ± 4.10 b·min⻹) was higher with OCC from sets 2-4 (p ≤ 0.03), with no difference 3 minutes postexercise (p = 0.29). Rating of perceived exertion was higher with OCC after every set (OCC 15.10 ± 0.31 vs. CON 12.16 ± 0.50, p = 0.01). In conclusion, no differences exist for WBL between groups, although there was a trend for higher levels with OCC. The current protocol for practical occlusion did not significantly increase metabolic stress more than normal low-intensity exercise. This study does not support the use of knee wraps as a mode of blood-flow restriction.
Assuntos
Exercício Físico , Joelho/irrigação sanguínea , Joelho/fisiologia , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Meias de Compressão , Feminino , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Esforço Físico/fisiologia , Adulto JovemRESUMO
Undergraduate exercise science programs develop curricula by referring to standards set by professional organizations. A web-based survey was administered to 235 institutions with exercise science undergraduate programs to evaluate their adherence to stated curricular guidelines. Results indicate that 29% of institutions considered American College of Sports Medicine (ACSM) Knowledge, skills, and abilities (KSAs); 33% both ACSM and National Association for Sport and Physical Education (NASPE) guidelines; 6% ACSM, NASPE, and National Strength and Conditioning Association (NSCA); 8% ACSM, NASPE, NSCA, and American Society of Exercise Physiologists, and 5% NASPE. The two largest subgroups had good compliance with the areas of exercise physiology, biomechanics, and human anatomy and physiology. However, neither subgroup adhered to the areas of exercise prescription, testing, and implementation; exercise and aging; or exercise with special populations. Regardless of the implemented guideline(s), most institutions placed minimal emphasis on areas related to health promotion and many curricula did not require any field experience.
Assuntos
Currículo , Educação em Saúde/normas , Medicina Esportiva/educação , Acreditação , Certificação , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Estados UnidosRESUMO
The purpose of this study was to determine the extent to which scientific research influences college strength and conditioning coaching practices and to determine the training methods utilized. A total of 321 surveys were mailed to Division I strength and conditioning coaches, and the response rate was 42.7% (137 of 321 surveys). Results indicate that all subjects held a baccalaureate degree, the majority in a human performance-related field, and that 75% were Certified Strength and Conditioning Specialist (CSCS) certified. The respondents' most widely utilized professional resources were the Strength and Conditioning Journal (94%) and other collegiate coaches and programs (93%). Forty-seven percent of respondents indicated that other collegiate coaches and their programs were the most important sources of knowledge outside of formal education. The majority indicated that they used a periodization protocol (93%) utilizing multiple sets (97%), plyometrics (90%), explosive movements (88%), and Olympic lifts (85%). Respondents tend to rely on sources of information that may not be defined as scientific, as evidenced by the low priority given to peer-reviewed literature. Respondents also tend to employ the methods they utilized as athletes. Reliance on these sources may not take advantage of advances made through scientific research in exercise physiology, biomechanics, and more specifically the area of strength and conditioning.
Assuntos
Músculo Esquelético/fisiologia , Educação Física e Treinamento/normas , Esforço Físico/fisiologia , Esportes/fisiologia , Adolescente , Adulto , Coleta de Dados , Feminino , Humanos , Masculino , Missouri , Fadiga Muscular , Educação Física e Treinamento/tendências , Resistência Física/fisiologia , Aptidão Física , Medicina Esportiva , Estatística como AssuntoRESUMO
The purpose of the study was to determine the metabolic cost of operating a bicycle generator (dynamo) light. Nineteen subjects (12 males, 7 females) volunteered to participate in the study. All tests were conducted using a multigeared road bicycle mounted on a Velodyne computer-controlled, electromagnetically-braked bicycle training simulator. A tyre sidewall-driven 6V 3W bicycle generator was attached to the bicycle frame. Tyre pressure was maintained at 6.12 atm. Gears were prescribed to produce simulated riding speeds of approximately 13 and 21 km h(-1) at 62 rpm. Subjects rode four, 5-min stages during the test session to evaluate riding under conditions of generator OFF or ON at each speed. Oxygen consumption, heart rate, and rating of perceived exertion (RPE) were recorded at the end of each minute. Paired samples t tests revealed significant differences between generator OFF and ON conditions for both the metabolic cost of cycling and heart rate at each of the speeds tested. There were no significant differences found between conditions for RPE. Bicycling with the generator ON increased oxygen consumption by 8.4% at 13 km h(-1) and 9.6% at 21 km h(-1).