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Abstract

The main purpose of the present study was to investigate the effect of 16 weeks of resistance training (RT) on body water in men and women. Thirty men (22.7 ± 4.4 years, 68.4 ± 9.0 kg and 174.5 ± 6.6 cm) and 34 women (22.7 ± 4.1 years, 58.8 ± 11.9 kg and 162.6 ± 6.2 cm) underwent progressive RT for 16 weeks (2 phases, 8 weeks each), 3 times per week, that consisted of 10-12 whole body exercises with 3 sets of 8-12 repetitions maximum. Total body water, TBW (intracellular water, ICW and extracellular water, ECW compartments) and skeletal muscle mass (SMM) were assessed using a spectral bioelectrical impedance device (Xitron 4200 Bioimpedance Spectrum Analyzer). TBW, ICW compartment and SMM increased significantly (P < 0.05) over time in men (+7.5%, +8.2% and +4.2%, respectively) and women (+7.6%, +11.0% +3.9%, respectively), with no sex by time interaction (P > 0.05). We conclude that progressive RT promotes an increase in body water, principally by intracellular content; however, the hydration status is not influenced by sex.

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... Epidemiological studies have shown that in the early postmenopausal years fractures of the wrist and spine are more incidental, whereas in older women, hip fractures become more common 14 . According to Ki-Soo et al 15 , in Korea, the disease affects 7.5% of men over 50 years old against 37.3% of women, of whom about 15% will need medical treatment due to fractures caused by the disease 2 . ...
... Marital status showed a significant correlation with the absence of osteoporosis; there was a lower proportion of married elderly women with a diagnosis of osteoporosis. This finding resembles the study of Lee et al. 16 whose objective was to investigate whether the social support network of the elderly influenced the presence of osteoporosis 15 . Three types of support networks were measured: objective support, subjective support and use of support. ...
... Three types of support networks were measured: objective support, subjective support and use of support. The results of the study showed that elderly people with a larger social support network had a lower incidence of osteoporosis, as well as elderly people married and that lived with other people 15 . Another study suggested that being married could be beneficial for bone health. ...
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This study examine the prevalence and factors associated to osteoporosis among older adults users of the primary health care. This cross-sectional study was carried out with 654 older adults (56% women) from primary health care in Maringá, Paraná, Brazil. The instruments used were the sociodemographic questionnaire and the International Physical Activity Questionnaire (IPAQ), short version. Data analysis was conducted through Chi-square test and Binary Logistic Regression (p < 0.05). The results showed a prevalence of 15.6% of older adults who reported the presence of osteoporosis. There was a higher prevalence of women with osteoporosis (p = 0.001), and on the other hand, there was a greater proportion of married elderly individuals (p = 0.003), and elderly with income above three minimum wages (p = 0.020) with absence of osteoporosis. The results showed that women (OR = 4.45; 95%CI: 2.47-8.01) and the older adults who take more than two medications (OR = 1.67; 95%CI: 1.15-2.42) were more likely to present osteoporosis. Older adults who presented a history of falls are 47.0% more likely to present osteoporosis. It was concluded that sex, the amount of medications and the history of falls are associated with the prevalence of osteoporosis in the older adults.
... Indeed, when matched for physiological effort (at the load/power eliciting individual ventilatory threshold/onset of blood lactate accumulation at 4 mmol L −1 ), resistance training modalities (half squats and bench press) have been shown to elicit similar acute VO 2 to 'cardio' modality exercise (lower and upper body cycling (Vilaca-Alves et al., 2016). Further, high effort resistance training increases muscle water content (Giessing et al., 2016;Ribiero et al., 2014) resulting in muscle swelling that appears to be largely independent of external load (Loenneke et al., 2016). As such it is perhaps unsurprising that high effort aerobic modalities also increase muscle water content (Mora-Rodriguez et al., 2016) and result in muscle swelling (Ozaki et al., 2013b). ...
... As already noted, blood lactate response in both conditions was similar indicating similar levels of metabolite accumulation, and subsequently, similar changes in Q t occurred indicating similar degrees of muscular swelling. Although prior studies have reported that both 'cardio' exercise and resistance training performed to high intensities of effort can induce increases in muscle water content and produce acute muscular swelling (Ozaki et al., 2013b;Giessing et al., 2016;Ribiero et al., 2014;Loenneke et al., 2016;Mora-Rodriguez et al., 2016), this appears to be the first to directly compare these responses between modalities when effort and duration matched. Cellular swelling has also been argued to be a trigger associated with the proliferation of satellite cells and thus a contributor to the hypertrophic response to exercise (Schoenfeld, 2013;De Freitas et al., 2017). ...
Article
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The present study examined the effects of exercise utilising traditional resistance training (leg press) or 'cardio' exercise (recumbent cycle ergometry) modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 × 12RM using a 2 s concentric and 3 s eccentric repetition duration controlled with a metronome, thus each set lasted 60 s; recumbent cycle ergometer: 4 × 60 s bouts using a resistance level permitting 80-100 rpm but culminating with being unable to sustain the minimum cadence for the final 5-10 s). Measurements included VO 2 , respiratory exchange ratio (RER), blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by 'condition' in any of the physiological responses examined (all p > 0.05). The present study shows that, when both effort and duration are matched, resistance training (leg press) and 'cardio' exercise (recumbent cycle ergometry) may produce largely similar responses in VO 2 , RER, blood lactate, energy expenditure, muscle swelling, and electromyography. It therefore seems reasonable to suggest that both may offer a similar stimulus to produce chronic physiological adaptations in outcomes such as cardiorespiratory fitness, strength, and hypertrophy. Future work should look to both replicate the study conducted here with respect to the same, and additional physiological measures, and rigorously test the comparative efficacy of effort and duration matched exercise of differing modalities with respect to chronic improvements in physiological fitness
... Indeed, when matched for physiological effort (at the load/power eliciting individual ventilatory threshold/onset of blood lactate accumulation at 4 mmol L −1 ), resistance training modalities (half squats and bench press) have been shown to elicit similar acute VO 2 to 'cardio' modality exercise (lower and upper body cycling (Vilaca-Alves et al., 2016). Further, high effort resistance training increases muscle water content (Giessing et al., 2016;Ribiero et al., 2014) resulting in muscle swelling that appears to be largely independent of external load (Loenneke et al., 2016). As such it is perhaps unsurprising that high effort aerobic modalities also increase muscle water content (Mora-Rodriguez et al., 2016) and result in muscle swelling (Ozaki et al., 2013b). ...
... As already noted, blood lactate response in both conditions was similar indicating similar levels of metabolite accumulation, and subsequently, similar changes in Q t occurred indicating similar degrees of muscular swelling. Although prior studies have reported that both 'cardio' exercise and resistance training performed to high intensities of effort can induce increases in muscle water content and produce acute muscular swelling (Ozaki et al., 2013b;Giessing et al., 2016;Ribiero et al., 2014;Loenneke et al., 2016;Mora-Rodriguez et al., 2016), this appears to be the first to directly compare these responses between modalities when effort and duration matched. Cellular swelling has also been argued to be a trigger associated with the proliferation of satellite cells and thus a contributor to the hypertrophic response to exercise (Schoenfeld, 2013;De Freitas et al., 2017). ...
Article
Full-text available
The present study examined the effects of exercise utilising traditional resistance training (leg press) or 'cardio' exercise (recumbent cycle ergometry) modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 × 12RM using a 2 s concentric and 3 s eccentric repetition duration controlled with a metronome, thus each set lasted 60 s; recumbent cycle ergometer: 4 × 60 s bouts using a resistance level permitting 80-100 rpm but culminating with being unable to sustain the minimum cadence for the final 5-10 s). Measurements included VO 2 , respiratory exchange ratio (RER), blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by 'condition' in any of the physiological responses examined (all p > 0.05). The present study shows that, when both effort and duration are matched, resistance training (leg press) and 'cardio' exercise (recumbent cycle ergometry) may produce largely similar responses in VO 2 , RER, blood lactate, energy expenditure, muscle swelling, and electromyography. It therefore seems reasonable to suggest that both may offer a similar stimulus to produce chronic physiological adaptations in outcomes such as cardiorespiratory fitness, strength, and hypertrophy. Future work should look to both replicate the study conducted here with respect to the same, and additional physiological measures, and rigorously test the comparative efficacy of effort and duration matched exercise of differing modalities with respect to chronic improvements in physiological fitness.
... Indeed, when matched for physiological effort (at the load/power eliciting individual ventilatory threshold/onset of blood lactate accumulation at 4 mmol L −1 ), resistance training modalities (half squats and bench press) have been shown to elicit similar acute VO 2 to 'cardio' modality exercise (lower and upper body cycling (Vilaca-Alves et al., 2016). Further, high effort resistance training increases muscle water content (Giessing et al., 2016;Ribiero et al., 2014) resulting in muscle swelling that appears to be largely independent of external load (Loenneke et al., 2016). As such it is perhaps unsurprising that high effort aerobic modalities also increase muscle water content (Mora-Rodriguez et al., 2016) and result in muscle swelling (Ozaki et al., 2013b). ...
... As already noted, blood lactate response in both conditions was similar indicating similar levels of metabolite accumulation, and subsequently, similar changes in Q t occurred indicating similar degrees of muscular swelling. Although prior studies have reported that both 'cardio' exercise and resistance training performed to high intensities of effort can induce increases in muscle water content and produce acute muscular swelling (Ozaki et al., 2013b;Giessing et al., 2016;Ribiero et al., 2014;Loenneke et al., 2016;Mora-Rodriguez et al., 2016), this appears to be the first to directly compare these responses between modalities when effort and duration matched. Cellular swelling has also been argued to be a trigger associated with the proliferation of satellite cells and thus a contributor to the hypertrophic response to exercise (Schoenfeld, 2013;De Freitas et al., 2017). ...
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The present study examined the effects of exercise utilising traditional resistance training (leg press) or ‘cardio’ exercise (recumbent cycle ergometry) modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 x 12RM, recumbent cycle ergometer: 4 x 60 second sprints). Measurements included VO2, respiratory exchange ratio (RER), blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by ‘condition’ in any of the physiological responses examined (all p > 0.05). The present study shows that, when both effort and duration are matched, resistance training and ‘cardio’ exercise produce largely similar physiological responses.
... modalidade esportiva e características ambientais desempenham um papel fundamental na otimização do desempenho e na manutenção da saúde de atletas(Belval et al., 2019).O presente estudo apresenta achados divergentes aos apresentados por estudos comparando a diferença entre os sexo sem utilizar a citada equação de variação percentual(Ribeiro et al., 2014), o que mostra a importância desta forma de análise e sua sensibilidade. Porém, o presente apresentou achados similares, com diferenças sérias entre os sexos, aos estudos que utilizaram o hematócrito para controle do estado de hidratação(Weitkunat et al., 2012).Pacientes com doenças cardíacas apresentam maior proporção de neutrófilos/linfócitos e proporção de plaquetas/linfócitos, proporções estas que são marcadores inflamatórios, e recuperação mais lenta da frequência cardíaca após exercício (Yurtdas et al., 2014). ...
Article
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Objetivos: Poucos estudos tem dado a devida importância ao estado de hidratação e as alterações hematológicas em menores de 18 anos. O presente estudo investigou estas alterações em menores de 18 anos na prova de 3000 metros para ambos os gêneros. Método: Foram incluídos os seis melhores participantes das Olimpíadas Nacionais do Ensino Médio (menores de 18 anos) no Brasil. Trata-se de um estudo observacional e transversal. Os atletas correram 3.000 metros em uma pista oval de 400 metros. Foi realizado leucograma total e específico, eritrograma e contagem de plaquetas em quatro diferentes tempos (jejum, pré, pós e recuperação). Os cálculos de comparação entre tempos, apresentados, foram adaptados do modelo matemático de variação percentual. Resultados: Quando comparadas as médias em relação a cada tempo, pode-se notar que os eritrócitos, hemoglobina, hematócrito, leucócitos totais e basófilos aumentaram significativamente após a corrida para ambos os gêneros. Além disso, as plaquetas também aumentaram para ambos os gêneros sem significância. O coeficiente de correlação de Pearson mostrou importante interação leucócitos-plaquetas. Os homens recuperaram seu estado de hidratação em quase metade do tempo em relação as mulheres. Em relação ao sistema imune e resposta inflamatória, as atletas do gênero feminino tiveram um aumento relativo de mais que o dobro para leucócitos e não recuperaram estes valores, além de apresentarem um aumento de eosinófilos neste mesmo tempo, enquanto os atletas do gênero masculino apresentaram diminuição. As mulheres apresentaram um aumento de quase o dobro para linfócitos, enquanto os homens tiveram este comportamento para os fagócitos. Conclusões: O exercício induz alteração do estado de hidratação e sistema imune, tendo diferenças em relação ao gênero. Quando bem conduzido, gera efeitos antiinflamatórios a longo prazo. Quando não há controle sobre o volume, intensidade e recuperação pode causar imunossupressão e promover a suceptibilidade para infecções. Foi possível observar que os atletas do gênero masculino tem um menor estresse inflamatório e recuperam o seu estado de hidratação e a resposta inflamatória mais rápido que as meninas após uma corrida de 3000 metros. Objectives: Few studies have given due importance to the hydration status and hematological alterations in children under 18 years of age. The present study investigated these alterations in children under 18 years old in the 3000 meters test for both genders. Method: The six best participants of Brazil's National High School Olympiads (under 18 years old) were included. This is an observational and cross-sectional study. Athletes ran 3,000 meters on a 400 meters oval track. Total and specific white blood cell count, erythrogram, and platelet count were performed four times (fasting, pre, post, and recovery). The time comparison calculations presented were adapted from the percentage variation mathematical model. Results: When comparing the means for each time, it can be noted that erythrocytes, hemoglobin, hematocrit, total leukocytes, and basophils increased significantly after the race for both genders. Furthermore, platelets also increased for both genders without significance. Pearson's correlation coefficient showed a significant leukocyte-platelet interaction. Men regained their hydration status in almost half the time compared to women. Regarding the immune system and inflammatory response, female athletes had a relative increase of more than double for leukocytes and did not recover these values, in addition to showing an increase in eosinophils simultaneously, while male athletes showed a decrease. Women showed an increase of almost double for lymphocytes, while men showed this behavior for phagocytes. Conclusions: Exercise induces changes in hydration status and immune system, with differences concerning gender. When done well, it generates long-term anti-inflammatory effects. When there is no control over volume, intensity, and recovery, it can cause immunosuppression and increase infection susceptibility. It was observed that male athletes have lower inflammatory stress and recover their hydration status and inflammatory response faster than girls after a 3000 meter run.
... The classical proposed mechanism for muscle strength adaptations consists of neural adaptations followed by contributions from muscle hypertrophy [46,47]. However, it is important to note that recent experimental studies [48][49][50] showed evidence against changes in muscle size as a major mechanism contributing to increases in muscular strength, which more recently increased the discussion about this topic [51][52][53]. Neural adaptations such as changes in the primary motor cortex [54], spinal cord [55], motor neuron alterations [56], and/or fiber level alterations (e.g., myosin motors, myofibrillar ATPase adaptations, the pattern of calcium release, and/or changes in the major components involved in the excitation-contraction coupling process) [57,58] are proposed to explain the gains in muscle strength following RT. ...
Article
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A detraining period after resistance training causes a significant decrease in trained-induced muscular adaptations. However, it is unclear how long muscle strength and hypertrophy gains last after different detraining periods. Thus, the present systematic review with meta-analysis aimed to evaluate the chronic effects of detraining on muscle strength and hypertrophy induced by resistance training. Searches were conducted on PubMed, Scopus, EBSCO, CINAHL, CENTRAL, and Web of Science. The difference in means and pooled standard deviations of outcomes were converted into Hedges’ g effect sizes (g). Twenty randomized and non-randomized trials (high and moderate risks of bias, respectively, and fair quality) were included for qualitative analysis of muscle strength and hypertrophy, while only two studies were included in the meta-analysis for maximum muscle strength. The resistance training group presented a significant increase in one-repetition maximum (1RM) chest press (g: 4.43 [3.65; 5.22], p < 0.001) and 1RM leg press strength (g: 4.47 [2.12; 6.82], p < 0.001) after training. The strength gains observed in the resistance training group were also maintained after 16–24 weeks of detraining (g: 1.99 [0.62; 3.36], p = 0.004; and g: 3.16 [0.82; 5.50], p = 0.008; respectively), when compared to the non-exercise control group. However, 1RM chest press and leg press strength level was similar between groups after 32 (g: 1.81 [−0.59; 4.21], p = 0.139; and g: 2.34 [−0.48; 5.16], p = 0.104; respectively) and 48 weeks of detraining (g: 1.01 [−0.76; 2.79], p = 0.263; and g: 1.16 [−1.09; 3.42], p = 0.311; respectively). There was not enough data to conduct a meta-analysis on muscular hypertrophy. In conclusion, the present systematic review and meta-analysis demonstrated that, when taking random error into account, there is no sufficient high-quality evidence to make any unbiased claim about how long changes in muscle strength induced by RT last after a DT period. Moreover, the effect of different DT periods on muscle hypertrophy induced by RT remains unknown since there was not enough data to conduct a meta-analysis with this variable.
... t1) are usually characterized by a daily training softer. Therefore, the increase in Xc/h from t0 to t1 in competitive subjects was significantly higher than in non-competitive probably in relation to the improvement in the muscular trophism with increased levels of intracellular proteins and glycogen which trigger increased intracellular body water levels (Ribeiro et al., 2014). Also rICW and PA increased from t0 to t1: probably a reduced stress from the training can explain such results. ...
Article
Purpose: Conventional Bioelectrical Impedance Analysis (BIA) or Bioelectrical Impedance Vector Analysis (BIVA) can provide direct evaluations of body composition. The purpose of this study was to evaluate lean and fat mass (FM), and hydration of children involved in daily competitive sports. Methods: 190 non-athletic [8.2-10.5 years] and 29 competitive children [8.0-10.5 years] were enrolled. They were evaluated: at baseline (t0), 6 months (t1) and one year (t2). Anthropometric, BIA and BIVA, lean and FM, and hydration evaluations were performed. Results: Resistance (R/h) and reactance (Xc/h) were lower at t0 in competitive individuals when compared to controls. Xc/h (+3.28) significantly increases in competitive when compared to non-competitive individuals (+0.66, p for difference: 0.011), while phase angle (PA) was lower at t0 (5.72 vs. 6.17, p < .001) and after 6 months (p = .001). Total body water adjusted for height (TBW/h) significantly increased only in non-athletes (+0.50 ± 0.13, p < .001) between t0 and t1. At t1, extracellular water (ECW) significantly decreased (p = .026) in the two groups: -0.45 ± 0.19% in non-competitive, -1.63 ± 0.49% in competitive subjects, while intracellular water (ICW) increased. At one-year follow-up (t2), there were no statistically significant differences in R/h, Xc/h and PA in competitive individuals when compared to baseline and t1. Furthermore, we observed at t2 that hours/week of training, age, male gender and body mass index can influence FFM/h and FM/h in both competitive and non-competitive subjects. In particular, a direct correlation was for hours/week and FFM/h, inverse for hours/week and FM/h. Conclusions: Body mass index does not allow evaluating differences in lean body mass and FM between athletes and non-athletes. BIA and BIVA can give more reliable details about body composition differences in competitive adolescents and non-competitive, outlining a progressive decline in ECW and increase in ICW without affecting TBW composition of athletes.
... The present investigation observed that the RT protocol promoted a significant increase in ICW. This result is in agreement with previous investigations (dos Santos et al., 2016;Ribeiro et al., 2014Ribeiro et al., , 2016Souza et al., 2016). Our results showed that the ratio between ICW and SMM did not change with training. ...
Article
The purpose of the present study was to investigate the effect of two different resistance training (RT) prescription methods on phase angle (PA) in older women. Seventy-six older women (68.5±5.7 years) were randomly assigned to one of three groups: Two training groups that performed an 8 week RT program either in a constant-load (CT, n= 25) or an ascending pyramidal-load (PR, n= 26) routine 3 times per week, or a control group (CG, n= 25) that performed no exercise. The CT program consisted of 3 sets of 8-12 RM with a constant load for the 3 sets, whereas the PR training consisted of 3 sets of 12/10/8 RM with incremental loads for each set. PA was assessed by whole-body spectral bioelectrical impedance. After the RT period, both CT and PR achieved higher (P<0.05) values of PA (CT= 5.76±0.59 degrees, PR= 5.63±0.61 degrees, CG= 5.48±0.46 degrees) compared to the CG, however, there was no difference (P> 0.05) between trained groups. The results suggest that 8 weeks of RT based on a PR and CT loads routines promote an improvement in PA, and both prescription methods performed similarly.
... Both groups experienced decreases in total and intracellular, but not extracellular water. These results are in contrast with Ribeiro et al. (34) who reported increases in total body water and intracellular and extracellular water after 16 weeks of resistance training in men and women. The authors noted that the greatest increases in intracellular water occurred during the final 8 weeks of training. ...
Article
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Twenty young women (20.3+1.5 years, 164+6 cm, 68.7+13.8 kg) without prior structured resistance training experience were recruited for this study. Body composition (BodPod), compartmental water (Bioelectrical Impedance), 7-site skinfold, and arm and thigh CSA were assessed pre- and post- 8 week training. Performance testing consisted of vertical jump, 3 kg chest pass initial velocity, squat 1RM and overhead press 1RM. Following 2 weeks of familiarization training, subjects were matched for body composition and relative squat strength, and randomly assigned to either a high- (HL: n=10; 4 sets of 5-7 repetitions) or moderate-load (ML: n=10; 2 sets of 10-14 repetitions) group that completed 6-7 exercises per day performed to momentary muscular failure. Training was divided into two lower and one upper body training sessions per week performed on non-consecutive days for 8 weeks. There were no statistically significant main effects for group or group x time interactions for any variable assessed. Both HL and ML resulted in similar significant increases in lean body mass (1.5 + .83 kg), lean dry mass (1.32 + 0.62 kg), thigh CSA (6.6 + 5.6 cm), vertical jump (2.9 + 3.2 cm), chest pass velocity (0.334 + 1.67 m/s), back squat 1 RM (22.5 + 8.1 kg), and overhead press (3.0 + 0.8 kg). HL and ML also both resulted in significant decreases in percent body fat (1.3 + 1.3 %), total body water (0.73 + 0.70 L), and intracellular water (0.43 + 0.38 L). The results of this study indicate that both moderate- and high-load training are effective at improving muscle growth, body composition, strength and power in untrained young women.
... This result is in agreement with previous investigations (Ribeiro et al., 2014;Ribeiro et al., 2017;Souza et al., 2016). The increase in ICW may be related to several factors, although a "Effects of Single Set Resistance Training With Different Frequencies on a Cellular Health Indicator in Older Women" by Ribeiro AS et al. ...
Article
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The main purpose of this study was compare the effects of resistance training (RT) performed two versus three times per week on phase angle (a cellular health indicator) in older women. Thirty-nine women (69.1±5.5 years) were randomly assigned to perform a RT program two (G2X) or three (G3X) days per week for 12 weeks. The RT was a whole-body program (8 exercises, 1 set, 10-15 repetitions). Phase angle, resistance, reactance, and total body water were assessed by bioimpedance spectroscopy. Intracellular water, reactance, and phase angle increased significantly in G2X (2.1%, 3.0%, and 5.6%, respectively) and G3X (5.0%, 6.9%, and 10.3% respectively) from pre- to post-training, with no significant difference between groups. Bioimpedance resistance decreased similarly in both groups (G2X=-1.7% vs. G3X=-3.2%). We conclude that a single set RT program with a frequency of two days per week may be sufficient to promote an improvement in cellular health in older women.
... Bioelectrical impedance analysis (BIA) is an easy-to-use, non-invasive and relatively inexpensive technique to estimate total body fat [13][14][15]. We used single frequency BIA (BIA 101-Body Impedance Analyzer Akern) as described in the manual [16], and analyzed the BIA output with the body composition software (BodyComposition-Professional v9.0.14325), using the equations from Sun [17] and the equations from Sergi [18]. ...
Article
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PurposeIncreased gut permeability causes the trespass of antigens into the blood stream which leads to inflammation. Gut permeability reflected by serum zonulin and diversity of the gut microbiome were investigated in this cross-sectional study involving female study participants with different activity and BMI levels. Methods102 women were included (BMI range 13.24–46.89 kg m−2): Anorexia nervosa patients (n = 17), athletes (n = 20), normal weight (n = 25), overweight (n = 21) and obese women (n = 19). DNA was extracted from stool samples and subjected to 16S rRNA gene analysis (V1–V2). Quantitative Insights Into Microbial Ecology (QIIME) was used to analyze data. Zonulin was measured with ELISA. Nutrient intake was assessed by repeated 24-h dietary recalls. We used the median of serum zonulin concentration to divide our participants into a “high-zonulin” (> 53.64 ng/ml) and “low-zonulin” (< 53.64 ng/ml) group. ResultsThe alpha-diversity (Shannon Index, Simpson Index, equitability) and beta-diversity (unweighted and weighted UniFrac distances) of the gut microbiome were not significantly different between the groups. Zonulin concentrations correlated significantly with total calorie-, protein-, carbohydrate-, sodium- and vitamin B12 intake. Linear discriminant analysis effect size (LEfSe) identified Ruminococcaceae (LDA = 4.163, p = 0.003) and Faecalibacterium (LDA = 4.151, p = 0.0002) as significantly more abundant in the low zonulin group. Conclusion Butyrate-producing gut bacteria such as Faecalibacteria could decrease gut permeability and lower inflammation. The diversity of the gut microbiota in women does not seem to be correlated with the serum zonulin concentration. Further interventional studies are needed to investigate gut mucosal permeability and the gut microbiome in the context of dietary factors.
... The phase angle is inversely proportional to resistance; resistance, in turn, depends on both intra and extracellular water [42]. Physical training, especially when it causes an increase in muscle mass, can lead to increase the intracellular water [43], which reduces the resistance and consequently leads to an increase of the phase angle. The reactance is directly proportional to the phase angle and depends on the integrity of the cell membrane [42]. ...
Article
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Objective: To evaluate the relationship between physical activity and phase angle. Design: Systematic Review and Meta-analysis. Data sources: Electronic searches of MEDLINE (via PUBMED), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), SciELO, LILACS, SPORTDiscus, Scopus, and Web of Science from inception to December 10th, 2017. Eligibility criteria for selecting studies: The PICOS strategy was defined, in which "P" corresponded to participants of any age, sex or ethnicity, "I" indicated any type of physical activity program, "C" denoted lack of exercise or irregular physical activity, "O" corresponded to the phase angle obtained by bio-impedance, and "S" indicated longitudinal or cross-sectional studies. Results: In cross-sectional studies the phase angle was higher among the active individuals (MD = 0.70; 95% CI: 0.48, 0.92, P < 0.001), with low heterogeneity (I2 = 0%; P = 0.619). In longitudinal studies, the mean of the difference of phase angles from the baseline was significantly higher for the active group than the control group (MD = 0.30; 95% CI: 0.11, 0.49, P = 0.001), with low heterogeneity (I2 = 13%, P = 0.331). No evidence of publication bias was found and the overall risk of bias was moderate to high. Summary/conclusion: The positive association of physical activity with phase angle reinforces the importance of routinely including exercise in health care. We also identified the need for further studies to define with different types, intensities and frequencies of exercises should be conducted in order to find the best dose-effect relationship.
... On the basis of the results of these studies, one might speculate that strength training could increase passive stiffness without affecting either maximum ROM or the MTU viscoelastic response. In addition to the possible underlying neural adaptations, such results might be partly attributable to an increase in muscle water content after strength training (64), which increases the resistance of muscle to stretch (72). They might also be associated with increases in muscle cross-sectional area, since cross-sectional area has been correlated with muscle stiffness (44, 67). ...
Article
The aim of this mini-review is to describe the current state of knowledge regarding the effects of chronic changes in the patterns of muscle use (defined as changes lasting >1 week), including muscle stretching, strengthening and others, on the passive mechanical properties of healthy human skeletal muscles. Various forms of muscle stretch training and some forms of strength training (especially eccentric training) are known to strongly impact the maximum elongation capacity of muscles in vivo (i.e. maximum joint range of motion), largely by increasing our ability to tolerate higher stretch loads. However, only small effects are observed in the passive stiffness of the muscle-tendon unit (MTU) or the muscle itself, although a reduction in muscle stiffness has been observed in the plantar flexors after both stretching and eccentric exercise interventions. No changes have yet been observed in viscoelastic properties such as the MTU stress-relaxation response, although a minimum of evidence indicates that hysteresis during passive stretch-relaxation cycles may be reduced by muscle stretching training. Importantly, data exist for relatively few muscle groups, and little is known about the effects of age and sex on the adaptive process of passive mechanical properties. Despite the significant research effort afforded to understanding the effects of altered physical activity patterns on the maximum range of motion at some joints, further information is needed before it will be possible to develop targeted physical activity interventions with the aim of evoking specific changes in passive mechanical properties in individuals or in specific muscles and muscle groups.
... In the body composition assessment, better hydration status was one of the important factors demonstrated in the individually-trained players. Significant difference in intracellular fluid was found at all stages of preparation, and this ICW increase could reflect the body's response to strength training, as it is mentioned in Ribeiro et al. (2014), that muscle hypertrophy is closely connected with intracellular water increase. Kumar and colleagues' (2012) research also supports our finding that the individual training group attained higher average phase angle and lower resistance values at the end of the training preparation. ...
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The pre-season preparation aim is to improve the components of physical performance through the changes in training intensity, gradual increment in volume, variation in training frequency and optimizing the body composition. The problem in team sports is the lack of individualization, because most coaches in team sports focus their training on the group and not on improving each player’s strengths and weaknesses. The aim of this study is to identify differences in the body composition and physical performance of young ice-hockey players (15-18 years) with different pre-season training approaches (collective vs. individual). This longitudinal study monitored 13 ice-hockey players with collective training and 8 ice-hockey players with individual training during their pre-season preparation. Body composition was measured by bioimpedance analyzer BIA 101 (Akern, S.R.L.) and the Myotest PRO determined player physical performance in power, force and velocity. Performance and body composition comparisons showed gradual increase in the differences between the two studied groups during the training process. This increase escalated to significant differences in the final output test results and was especially noted in the upper limbs power and force (p=0.016; p
... However, after the 4-month training a small decrease of the training frequency due to life obligations brought back the FFM almost to the original levels. This means that the increase was probably mainly water-and glycogen-related (Ribeiro et al., 2014) and not actual myofibrillar protein increase. Small or negligible FFM increases for trained athletes are typically reported in the literature. ...
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Article History Weight (resistance) training can increase strength and muscle mass. A personalized training protocol (i.e., with optimum frequency and number of sets) was followed for 4 months by a 40-year old male with 20 years of weight training experience. The body was split in three parts and was trained every 5-6 days. The strength increase was between 7% (back) and 17% (legs), while the free-fat mass increase was 0.4 kg (0.5%), which was lost after the 4-month period. It was shown that reduced sleep duration for one night did not affect the strength performance. However, with 2 days of reduced sleep, there were indications of worse performance. The results confirm the importance of personalized weight training programs and good sleep habits for strength improvements. Contribution/Originality: This study documents that a personalized weight (resistance) training programs can result in strength increases even for advanced trainees. This study contributes in the existing literature showing that one-night sleep restriction only slightly affects strength performance, but two nights of reduced sleep duration have a negative effect.
... The present investigation observed that the RT protocol promoted a significant increase in ICW. This result is in agreement with previous work from our laboratory with young adult men and women (Ribeiro et al., 2014). The increase in ICW content may be related to several factors, although a definitive mechanism to support such a contention is not clear at this time. ...
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Phase angle (PhA) is an angular-derived bioelectrical impedance parameter based on resistance and reactance that has been widely used in different populations as an objective indicator of cellular health. The purpose of this study was to analyze the effect of resistance training (RT) on PhA in older women. Forty-one older women (67.2 ± 4.5 years, 64.0 ± 12.3 kg, 154.7 ± 5.2 cm, and 26.6 ± 4.8 kg/m(2) ) were randomly assigned to one of two groups: a training group (TG, n = 19) that underwent progressive RT for 12 weeks (eight exercises, three sets of 10-15 repetitions maximum, three times per week) or a control group (CG, n = 22) that did not perform any type of exercise during the intervention period. Resistance, reactance, PhA, total body water (TBW), intracellular (ICW) and extracellular (ECW) water were assessed by spectral bioelectrical impedance. There was a significant group by time interaction (P < 0.05) for PhA, TBW, and ICW in which only the TG increased their scores after the intervention period (PhA = +6.5%, TBW = +2.8%, and ICW = +5.1%). The results suggest that progressive RT promotes an increase in PhA in older women. Therefore, the PhA seems to be a good parameter to assess changes in cellular health during RT intervention.
... However, many of the responses induced by RT appear to be sex-dependent 1-5 due to differences in muscular strength and mass, hormonal regulation, muscular architecture, energy storage, use of energy substrates, the muscular recovery process, and motor unit recruitment patterns, while other adaptive responses manifest themselves regardless of sex. 2,4,[6][7][8][9][10] Salvador et al. 1 revealed the presence of sexual dimorphism in strength endurance in women presenting a better response than men in multiple sets to failure, with 80% of one-repetition maximum (1-RM) after eight weeks of RT. On the other hand, the fatigue index improved similarly in both groups. ...
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Introduction Although resistance training (RT) can provide numerous benefits for both men and women, morphological, neuromuscular, metabolic, physiological, and behavioral differences between sexes may influence the magnitude of training responses. Objective To analyze the impact of 16 weeks of progressive RT on strength endurance in untrained men and women. Methods Twenty-eight men and 31 women (18-30 years) underwent a supervised RT program that was divided into two 8-week stages, 3 times per week on nonconsecutive days. The RT program was composed of exercises for different body segments (trunk, upper and lower limbs) that were performed with three sets of 8-12 repetitions maximum (RM), in 10 and 12 exercises, in the first and second stage, respectively. Strength endurance was assessed in 3 exercises (bench press, squat, and arm curl) and in a combination of these exercises through a protocol composed of 4 sets performed to failure with 80% of 1-RM on the baseline, after 8 and 16 weeks of RT. Results Group vs. time interactions (p <0.05) were found for bench press (men = +28.3% vs. women = +32.1%), squat (men = +13.5% vs. women = +32.7%), and arm curl (men = +20.2% vs. women = +24.4%) exercises, as well as in the set of all 3 exercises (men = +18.4% vs. women = +31.2%). Conclusion Our results suggest that 16 weeks of RT can improve strength endurance in both men and women, although higher gains are achieved by women. Level of evidence II; Therapeutic study-Investigating treatment results.
... Thus, several studies evidencing that moderate or intense physical activity may be a non-pharmacological treatment for improved cognition. A study carried out in the city of Florianópolis with 875 sedentary elderly showed worse mental health and a significant increase of depressive symptoms 11 . Regular physical exercise can prevent or even reverse frequent problems found in the elderly during aging, reducing the noxious effects of cognitive decline [12][13][14] . ...
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This study proposed to evaluate the level of physical activity and the cognitive state of elderly users of Primary Care Facilities (UBS) of the Municipality of Maringá, State of Paraná, Brazil. This is a descriptive, cross-sectional, epidemiological study with 654 elderly men and women UBS users. A sociodemographic questionnaire, the Mini Mental State Examination (MMSE) and the short version of the International Physical Activity Questionnaire (IPAQ) were employed. Data was analyzed using the Kolmogorov-Smirnov, Chi-square, Kruskal-Wallis and Mann-Whitney "U" tests, with a significance level of p<0.05. However, they evidenced a high score in temporal orientation (Md = 5.0), spatial orientation (Md = 5.0), immediate memory (Md = 3.0), recall (Md = 3.0) and language (Md = 8.0). When comparing the mental state according to the level of physical activity of the elderly, we observed that very active/ active individuals had better attention and calculation (p = 0.036), recall (p = 0.001) and general cognitive status (p = 0.002) against irregularly active and sedentary elderly. Adequate levels of physical activity may be related to better scores of cognitive functions of elderly subjects.
... This apparently contradictory result is possibly explained by the fact that walking and standing on one foot are mainly determined by a large number of lower limb muscles, while muscle strength (assessed by hand grip) is mainly determined by a small number of upper limb muscles, and it is possible that ICW loss does not affect lower and upper limbs in the same way. Some evidence suggests that training may stimulate intracellular muscle hydration [17], so different muscle training packages may cause intracellular hydration to vary between muscles. New studies assessing specific muscle hydration and function packages are needed to elucidate the role of muscle cell hydration on muscle strength and functionality. ...
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Background: In aged populations, muscle strength depends more on muscle quality than on muscle quantity, while all three are criteria for the diagnosis of sarcopenia. Intracellular water content (ICW) in lean mass (LM) has been proposed as an indicator of muscle quality related to muscle strength in older people. Objectives: To evaluate the relationship between the ICW/LM ratio, muscle strength and indicators of functional performance in obese older adults, and to assess the value of the ICW/LM ratio as an indicator of muscle quality. Methodology: Design: cross-sectional study. Population: persons aged 65-75 years with a body mass index of 30-39 kg/m2. ICW and LM were estimated by bioelectrical impedance. Hand grip, gait speed, unipedal stance test, timed up-and-go (TUG) test, Barthel score and frailty (Fried criteria) were assessed. Sarcopenia was established according to EWGSOP2 criteria. Results: Recruited were 305 subjects (66% women), mean age 68 years. The ICW/LM ratio correlated with the TUG test, gait speed and grip strength, and was also associated with sex, the unipedal stance test and frailty. Independently of age, sex and muscle mass, the ICW/LM ratio was related with gait speed, the TUG test and unipedal stance capacity. One person (0.3%) had sarcopenia defined as low muscle strength and low muscle mass, while 25 people (8.2%) had sarcopenia defined as low muscle strength and poor muscle quality (ICW/LM). With this last definition, sarcopenia was related to frailty, gait speed and the TUG test. Conclusions: ICW content in LM could be a useful muscle quality indicator for defining sarcopenia. However, more studies are required to confirm our findings for other populations.
... On the other hand, PhA increases may be associated with cellular hydration influencing the resistive behavior (R) of bodily tissues. The increase in ICW content observed in the present investigation is in agreement with previous work from our laboratory that used the same RT protocol in a similar cohort of healthy young adult men and women [28]. Consistent RT can elicit cellular hydration by an increase in glycogen storage [19], since every gram of glycogen attracts 3 g of water [7]. ...
Article
The main purpose of the present study was to investigate the effect of a hypertrophy-type resistance training protocol on phase angle, an indicator of cellular integrity, in young adult men and women. Twenty-eight men (22.2 ± 4.3 years, 67.8 ± 9.0 kg and 174.2 ± 6.8 cm) and 31 women (23.2 ± 4.1 years, 58.7 ± 12.1 kg and 162.7 ± 6.4 cm) underwent a progressive RT for 16 weeks (2 phases, 8 weeks each), 3 times per week, consisting of 10 to 12 whole body exercises with 3 sets of 8-12 repetitions maximum. Phase angle, resistance, reactance, and total body water (intra and extracellular water compartments) were assessed by bioimpedance spectroscopy (Xitron 4200 Bioimpedance Spectrum Analyzer). Total body water, intracellular water, and phase angle increased significantly (P < 0.05) in men (7.8%, 8.3%, and 4.3%, respectively) and women (7.6%, 11.7%, and 5.8% respectively), with no significant difference between sexes (P > 0.05). Bioimpedance resistance decreased (P < 0.05) similarly in both sex (men = -4.8%, women = -3.8%). The results suggest that regardless of sex, progressive RT induces an increase in phase angle and a rise in cellular hydration.
... Several studies have reported the important contribute of exercise for cell membrane integrity and vitality, particularly in the long term, when a structural effect may be observed (chronic adaptation to exercise) 7,36,52 . Exercise is also a known stimulus for increasing muscle mass and was found to promote increase in intracellular water 58,59 , which has a positive effect on PhA 7,32 . In the present review, two studies showed effects on the PhA 33,36 . ...
Article
Introduction: Body composition is one of the main variables of interest in clinical practice in cancer patients. Specific markers from bioelectrical impedance analysis, such as phase angle (PhA), have been assuming increasing relevance in this population. The aim of the present systematic review was to study and systematise the effect of exercise on PhA in cancer survivors, as compared to control conditions, namely usual care, with no exercise. The effect of exercise on PhA in the population of cancer survivors is not yet established. EVIDENCE ACQUISITIONː This systematic review was conducted on October 13, 2021, through PubMed, Web of Science, Wiley Online Library, Directory of Open Access Journals, Science Direct and JSTOR, following PRISMA guidelines and PICOS model that include: cancer survivors with ≥18 years; intervention of any exercise program for the target group; comparison between intervention group and control group that followed control conditions, namely usual care, with no exercise; outcome related to PhA; and studies of randomized control trials. Evidence synthesis: We founded a total of 1244 publications, using selected keywords. Eight studies were included in this systematic review, after inclusion/exclusion criteria considered. Compared with the control conditions, exercise training programs seem associated with a positive effect on PhA, both in solid tumours and haematologic cancer types, but only when using resistance exercise alone. According to the best evidence synthesis criteria, we could not conclude the superiority of any exercise program analysed in the value of the PhA. Conclusions: There were several exercise details that may have potential to be beneficial for PhA in cancer patients, including an early start of the exercise intervention (during treatment and immediately after discharge from hospital), the use of resistance exercise or/and aerobic exercise, and mainly a long follow-up period (≥ 4 months) to verify the structural effects of exercise on the PhA. However, there were no effects on the PhA value immediately after the intervention, regardless of the type of protocol and the intervention time.
... Ademais, cabe destacar que uma única sessão de treinamento físico pode gerar redução de peso corporal oriunda da atenuação de água corporal e subs-tratos energéticos, por exemplo, o glicogênio muscular 26 . Sabe-se que a redução do peso corporal relaciona-se a melhora da imagem corporal 1 . ...
Article
The aim of this study was to investigate the acute effects of resistance training on body checking in women experienced in resistance training. 100 volunteers aged between 18 and 30 years, divided in training (TG) and control (CG) group were participated. Muscle strength was determined by 4-10 maximum repetitions test (RMS). Body checking behaviors were assessed for Body Checking and Avoidance Questionnaire (BCAQ). One resistance training session consisted of multi-joint and single-joint exercises. Participants were assessed 30 minutes, 24, 48 and 72 hours after resistance training session. Highlight that only the TG realized resistance training session. Because to the non-violation parametric, 2x2 ANOVA for repeated measures was conducted to compare the BCAQ scores according to time of research and group (TG x CG). A repeated measures ANOVA showed significant differences in scores of BCAQ between TG and CG after (30 minutes to 24 hours) the completion of the training session (F(2, 98)=27,71; p=0,001). A single session of resistance training was able to reduce up to 24 hours body checking behaviors of young adult female.
... These contributions may be explained, in part, by subcutaneous tissue thickness increasing or decreasing relative to exercise and recovery. Fat accumulation and edema display concurrent changes due to subcutaneous echogenicity (23), which may influence other physiological factors such as cellular water content. Physiological changes therein may also result in decreased intracellular water due to inactivity (5) along with consequential decreased sarcolemma which could negatively alter muscle fiber size and, in turn, protein concentrations affecting contractility (13). ...
Article
Travis, SK, Mujika, I, Zwetsloot, KA, Gentles, JA, Stone, MH, and Bazyler, CD. The effects of 3 vs. 5 days of training cessation on maximal strength. J Strength Cond Res XX(X): 000–000, 2021—The purpose of this study was to compare the effects of 3 vs. 5 days of training cessation on body composition, perceived recovery and stress state, and maximal strength. Nineteen strength-trained athletes (23.8 ± 4.1 year; 90.8 ± 20.7 kg; 174.2 ± 7.3 cm) completed a powerlifting specific 4-week training block followed by either 3 or 5 days of training cessation. During the 4-week training block, athletes were trained 3 days per week, performing 3–4 movements that included at least 2–3 competition lifts per session while performing 4–5 sets of 3–5 repetitions with intensity ranging from 75 to 100% 1 repetition maximum (1RM). Body composition, psychometric measures, upper-body maximal strength, and lower-body maximal strength were assessed before (T1) and after 4 weeks of training (T2) and at 3 or 5 days of training cessation (T3). The alpha level was set at p < 0.05. After the 4-week training block (T1 to T2), trivial significant increases in body mass (p = 0.016, Hedge's g = 0.04) and bench press 1RM (p = 0.01, g = 0.16) were observed, as well as small significant increases in back squat 1RM (p < 0.001, g = 0.23), deadlift 1RM (p = 0.003, g = 0.20), powerlifting total (p < 0.001, g = 0.21), and Wilks Score (p < 0.001, g = 0.27). There were no significant differences between groups for isometric back squat performance, psychometric measures, and body composition after training cessation (T2–T3). However, small significant decreases in isometric bench press performance were observed after 5 days (p < 0.001, g = 0.16), but not 3 days of training cessation. The results of this study suggest maximal lower-body strength can be preserved during 3 and 5 days of training cessation, but maximal upper-body strength is only preserved for 3 days after 4 weeks of strength training in athletes.
... modalidade esportiva e características ambientais desempenham um papel fundamental na otimização do desempenho e na manutenção da saúde de atletas(Belval et al., 2019).O presente estudo apresenta achados divergentes aos apresentados por estudos comparando a diferença entre os sexo sem utilizar a citada equação de variação percentual(Ribeiro et al., 2014), o que mostra a importância desta forma de análise e sua sensibilidade. Porém, o presente apresentou achados similares, com diferenças sérias entre os sexos, aos estudos que utilizaram o hematócrito para controle do estado de hidratação(Weitkunat et al., 2012).Pacientes com doenças cardíacas apresentam maior proporção de neutrófilos/linfócitos e proporção de plaquetas/linfócitos, proporções estas que são marcadores inflamatórios, e recuperação mais lenta da frequência cardíaca após exercício (Yurtdas et al., 2014). ...
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Objectives: Few studies have given due importance to the hydration status and hematological alterations in children under 18 years of age. The present study investigated these alterations in children under 18 years old in the 3000 meters test for both genders. Method: The six best participants of Brazil's National High School Olympiads (under 18 years old) were included. This is an observational and cross-sectional study. Athletes ran 3,000 meters on a 400 meters oval track. Total and specific white blood cell count, erythrogram, and platelet count were performed four times (fasting, pre, post, and recovery). The time comparison calculations presented were adapted from the percentage variation mathematical model. Results: When comparing the means for each time, it can be noted that erythrocytes, hemoglobin, hematocrit, total leukocytes, and basophils increased significantly after the race for both genders. Furthermore, platelets also increased for both genders without significance. Pearson's correlation coefficient showed a significant leukocyte-platelet interaction. Men regained their hydration status in almost half the time compared to women. Regarding the immune system and inflammatory response, female athletes had a relative increase of more than double for leukocytes and did not recover these values, in addition to showing an increase in eosinophils simultaneously, while male athletes showed a decrease. Women showed an increase of almost double for lymphocytes, while men showed this behavior for phagocytes. Conclusions: Exercise induces changes in hydration status and immune system, with differences concerning gender. When done well, it generates long-term anti-inflammatory effects. When there is no control over volume, intensity, and recovery, it can cause immunosuppression and increase infection susceptibility. It was observed that male athletes have lower inflammatory stress and recover their hydration status and inflammatory response faster than girls after a 3000 meter run.
... The ability of TB DXA to accurately and precisely measure BMD, fat and lean tissue within populations of differing muscle and fat mass is unlikely to be comparable [38] and a previous study demonstrated larger precision errors in spine, hip and total body in obese groups [14,39]. Furthermore, measurements in athletes are confounded due to water retention in skeletal muscle post training, with acute increases in muscle water content being demonstrated post strenuous resistance training [40,41]. Therefore scanning athletes using DXA to measure body composition requires consideration of the duration since their last training session to prevent adding further errors to the measurements. ...
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Roberts, BM, Nuckols, G, and Krieger, JW. Sex differences in resistance training: A systematic review and meta-analysis. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to determine whether there are different responses to resistance training for strength or hypertrophy in young to middle-aged males and females using the same resistance training protocol. The protocol was pre-registered with PROSPERO (CRD42018094276). Meta-analyses were performed using robust variance random effects modeling for multilevel data structures, with adjustments for small samples using package robumeta in R. Statistical significance was set at P < 0.05. The analysis of hypertrophy comprised 12 outcomes from 10 studies with no significant difference between males and females (effect size [ES] = 0.07 ± 0.06; P = 0.31; I = 0). The analysis of upper-body strength comprised 19 outcomes from 17 studies with a significant effect favoring females (ES = -0.60 ± 0.16; P = 0.002; I = 72.1). The analysis of lower-body strength comprised 23 outcomes from 23 studies with no significant difference between sexes (ES = -0.21 ± 0.16; P = 0.20; I = 74.7). We found that males and females adapted to resistance training with similar effect sizes for hypertrophy and lower-body strength, but females had a larger effect for relative upper-body strength. Given the moderate effect size favoring females in the upper-body strength analysis, it is possible that untrained females display a higher capacity to increase upper-body strength than males. Further research is required to clarify why this difference occurs only in the upper body and whether the differences are due to neural, muscular, motor learning, or are an artifact of the short duration of studies included.
Article
Muscle atrophy is a great consequence of spinal cord injuries (SCI) due to immobility. SCI’s detrimental effects on large muscle groups may lead to secondary effects such as glucose intolerance, increased risk of metabolic syndrome, and diabetes. Exercising with blood flow restriction (BFR) has been proposed as an effective method to induce hypertrophy using low training loads, with little or no muscle damage. This study investigated acute and chronic effects of low-intensity functional electrical stimulation (FES) combined with BFR on muscles affected by spinal cord injury. The acute effects of one bout of FES with (FES + BFR group) and without BFR (FES group) on muscle thickness (MT) and edema formation were compared. The chronic effects on MT and edema following 8 weeks of twice weekly training with and without BFR were also compared. The FES + BFR group showed MT and edema increases compared to the FES only group (p< 0.05). The FES + BFR showed a chronic MT increase after 4 weeks of training (p <0.05), with no further MT increases from the 4th to the 8th week (p>0.05). Following 3 weeks of detraining, MT decreased to baseline. No MT changes were observed in the FES (p>0.05). The FES + BF stimuli induced MT increases on the paralyzed skeletal muscles of SCI. The acute effects suggest that FES causes a greater metabolite accumulation and edema when combined with BFR. The early increases in MT can be attributed to edema, whereas after the 4th week, it is likely to be related to muscle hypertrophy. Register Clinical Trial Number on ReBeC: RBR-386rm8
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This study aimed to determine and compare the body composition, bioelectric parameters, and handgrip strength in federated and recreational Chilean climbers. Thirteen Chilean climbers voluntarily participated, being 4 federated (25.75 ± 2.87 years) and 9 recreational (22.33 ± 1.41 years). Body composition was measured using a multifrequency octopolar bioelectrical impedance meter, while handgrip strength was determined with a dynamometer. Although there were no statistical differences in the body composition variables between groups, the trunk phase angle was statistically higher in the federated compared to the recreational climbers (p = 0,011 [95 % CI = 1,10; 5,20]). Regarding handgrip strength, the relative strength was higher for federated (p = 0,025 [95 % CI = 0,10; 0,22]), while the difference in strength between dominant and non-dominant hand was higher for recreational climbers (p = 0,012 [95 % CI = 1,60; 10,05]). This study is one of the first that explore the differences between federated and recreational Chilean climbers. These results suggest a differentiation at the level of phase angle and handgrip strength, which should be corroborated in future studies.
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Aim: This study examined low volume resistance training (RT) in trained participants with and without advanced training methods. Methods: Trained participants (RT experience 4+3 years) were randomised to groups performing single set RT;; ssRM (n = 21) performing repetitions to self--determined repetition maximum (RM), ssMMF (n = 30) performing repetitions to momentary muscular failure (MMF), and ssRP (n = 28) performing repetitions to self--determined RM using a rest pause (RP) method. Each performed supervised RT 2x/week for 10 weeks. Outcomes included maximal isometric strength and body composition using bioelectrical impedance analysis. Results: The ssRM group did not significantly improve in any outcome. The ssMMF and ssRP groups both significantly improved strength (p < 0.05). Magnitude of changes using effect size (ES) was examined between groups. Strength ES's were considered large for ssMMF (0.91 to 1.57) and ranging small to large for ssRP (0.42 to 1.06). Body composition data revealed significant improvements (p < 0.05) in muscle and fat mass and percentages for whole body, upper limbs and trunk for ssMMF, but only upper limbs for ssRP. Body composition ES's ranged moderate to large for ssMMF (0.56 to 1.27) and ranged small to moderate for ssRP (0.28 to 0.52). ssMMF also significantly improved (p < 0.05) total abdominal fat and increased intracellular water with moderate ES's (--0.62 and 0.56 respectively). Conclusion: Training to self--determined RM is not efficacious for trained participants. Training to MMF produces greatest improvements in strength and body composition, however, RP style training does offer some benefit.
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It is well established that regimented resistance training can promote increases in muscle hypertrophy. The prevailing body of research indicates that mechanical stress is the primary impetus for this adaptive response and studies show that mechanical stress alone can initiate anabolic signalling. Given the dominant role of mechanical stress in muscle growth, the question arises as to whether other factors may enhance the post-exercise hypertrophic response. Several researchers have proposed that exercise-induced metabolic stress may in fact confer such an anabolic effect and some have even suggested that metabolite accumulation may be more important than high force development in optimizing muscle growth. Metabolic stress pursuant to traditional resistance training manifests as a result of exercise that relies on anaerobic glycolysis for adenosine triphosphate production. This, in turn, causes the subsequent accumulation of metabolites, particularly lactate and H(+). Acute muscle hypoxia associated with such training methods may further heighten metabolic buildup. Therefore, the purpose of this paper will be to review the emerging body of research suggesting a role for exercise-induced metabolic stress in maximizing muscle development and present insights as to the potential mechanisms by which these hypertrophic adaptations may occur. These mechanisms include increased fibre recruitment, elevated systemic hormonal production, alterations in local myokines, heightened production of reactive oxygen species and cell swelling. Recommendations are provided for potential areas of future research on the subject.
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Background: Bioelectrical impedance spectroscopy (BIS) provides an affordable assessment of the body's various water compartments: total body water (TBW), extracellular water (ECW) and intracellular water (ICW). However, little is known of its validity in athletes. Aim: To validate TBW, ECW and ICW by BIS in elite male and female Portuguese athletes using dilution techniques (i.e. deuterium and bromide dilution) as criterion methods. Subjects and methods: Sixty-two athletes (18.5 ± 4.1 years) had TBW, ECW and ICW assessed by BIS during their respective pre-season. Results: BIS significantly under-estimated TBW by 1.0 ± 1.7 kg and ICW by 0.9 ± 1.9 kg in relation to the criterion methods, with no differences observed for ECW. The values for the concordance correlation coefficient were 0.98 for TBW and ECW and 0.95 for ICW. Bland-Altman analyses revealed no bias for the various water compartments, with the 95% confidence intervals ranging from - 4.8 to 2.6 kg for TBW, - 1.5 to 1.6 kg for ECW and - 4.5 to 2.7 kg for ICW. Conclusions: Overall, these findings demonstrate the validity of BIS as a valid tool in the assessment of TBW and its compartments in both male and female athletes.
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Exercise-induced muscle damage (EIMD) occurs primarily from the performance of unaccustomed exercise, and its severity is modulated by the type, intensity, and duration of training. Although concentric and isometric actions contribute to EIMD, the greatest damage to muscle tissue is seen with eccentric exercise, where muscles are forcibly lengthened. Damage can be specific to just a few macromolecules of tissue or result in large tears in the sarcolemma, basal lamina, and supportive connective tissue, and inducing injury to contractile elements and the cytoskeleton. Although EIMD can have detrimental short-term effects on markers of performance and pain, it has been hypothesized that the associated skeletal muscle inflammation and increased protein turnover are necessary for long-term hypertrophic adaptations. A theoretical basis for this belief has been proposed, whereby the structural changes associated with EIMD influence gene expression, resulting in a strengthening of the tissue and thus protection of the muscle against further injury. Other researchers, however, have questioned this hypothesis, noting that hypertrophy can occur in the relative absence of muscle damage. Therefore, the purpose of this article will be twofold: (a) to extensively review the literature and attempt to determine what, if any, role EIMD plays in promoting skeletal muscle hypertrophy and (b) to make applicable recommendations for resistance training program design.
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Knowledge of patient fluid distribution would be useful clinically. Both single-frequency (SF) and impedance modeling approaches are proposed. The high intercorrelation between body water compartments makes determining the best approach difficult. This study was conducted to evaluate the merits of an SF approach. Mathematical simulation was performed to determine the effect of tissue change on resistance and reactance. Dilution results were reanalyzed, and resistance and parallel reactance were used to predict the intracellular water for two groups. Results indicated that the amount of intracellular and extracellular water conduction at any SF can vary with tissue change, and reactance at any SF is affected by all tissue parameters. Modeling provided a good prediction of dilution intracellular and extracellular water, but an SF method did not. Intracellular, extracellular, and total body water were equally predicted at all frequencies by SF resistance and parallel reactance. Extracellular and intracellular water are best measured through modeling, because only at the zero and infinite frequencies are the results sensitive only to extracellular and intracellular water. At all other frequencies there are other effects.
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The quest to increase lean body mass is widely pursued by those who lift weights. Research is lacking, however, as to the best approach for maximizing exercise-induced muscle growth. Bodybuilders generally train with moderate loads and fairly short rest intervals that induce high amounts of metabolic stress. Powerlifters, on the other hand, routinely train with high-intensity loads and lengthy rest periods between sets. Although both groups are known to display impressive muscularity, it is not clear which method is superior for hypertrophic gains. It has been shown that many factors mediate the hypertrophic process and that mechanical tension, muscle damage, and metabolic stress all can play a role in exercise-induced muscle growth. Therefore, the purpose of this paper is twofold: (a) to extensively review the literature as to the mechanisms of muscle hypertrophy and their application to exercise training and (b) to draw conclusions from the research as to the optimal protocol for maximizing muscle growth.
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This study assessed variability in muscle size and strength changes in a large cohort of men and women after a unilateral resistance training program in the elbow flexors. A secondary purpose was to assess sex differences in size and strength changes after training. Five hundred eighty-five subjects (342 women, 243 men) were tested at one of eight study centers. Isometric (MVC) and dynamic strength (one-repetition maximum (1RM)) of the elbow flexor muscles of each arm and magnetic resonance imaging (MRI) of the biceps brachii (to determine cross-sectional area (CSA)) were assessed before and after 12 wk of progressive dynamic resistance training of the nondominant arm. Size changes ranged from -2 to +59% (-0.4 to +13.6 cm), 1RM strength gains ranged from 0 to +250% (0 to +10.2 kg), and MVC changes ranged from -32 to +149% (-15.9 to +52.6 kg). Coefficients of variation were 0.48 and 0.51 for changes in CSA (P = 0.44), 1.07 and 0.89 for changes in MVC (P < 0.01), and 0.55 and 0.59 for changes in CSA (P < 0.01) in men and women, respectively. Men experienced 2.5% greater gains for CSA (P < 0.01) compared with women. Despite greater absolute gains in men, relative increases in strength measures were greater in women versus men (P < 0.05). Men and women exhibit wide ranges of response to resistance training, with some subjects showing little to no gain, and others showing profound changes, increasing size by over 10 cm and doubling their strength. Men had only a slight advantage in relative size gains compared with women, whereas women outpaced men considerably in relative gains in strength.
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SUMMARY In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 dIwkj1 for novice training, 3-4 dIwkj1 for intermediate training, and 4-5 dIwkj1 for advanced training. Similar program designs are recom- mended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (915) using short rest periods (G90 s). In the interpretation of this position stand as with prior ones, recommendations should be applied in context and should be contingent upon an individual's target goals, physical capacity, and training
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Objectives: To examine the possible influences of age and gender on muscle volume responses to strength training (ST). Design: Prospective intervention study. Setting: University of Maryland Exercise Science and Wellness Research Laboratories. Participants: Eight young men (age 20-30 years), six young women (age 20-30 years), nine older men (age 65-75 years), and ten older women (age 65-75 years). Intervention: A 6-month whole-body ST program that exercised all major muscle groups of the upper and lower body 3 days/week. Measurements: Thigh and quadriceps muscle volumes and mid-thigh muscle cross-sectional area (CSA) were assessed by magnetic resonance imaging before and after the ST program. Results: Thigh and quadriceps muscle volume increased significantly in all age and gender groups as a result of ST (P < .001), with no significant differences between the groups. Modest correlations were observed between both the change in quadriceps versus the change in total thigh muscle volume (r = 0.65; P < .001) and the change in thigh muscle volume versus the change in mid-thigh CSA (r = 0.76, P < .001). Conclusions: The results indicate that neither age nor gender affects muscle volume response to whole-body ST. Muscle volume, rather than muscle CSA, is recommended for studying muscle mass responses to ST.
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The purpose of this study was to test the validity of a multiple frequency bioimpedance spectroscopy (BIS) technique that estimates extracellular fluid volume (ECV), intracellular fluid volume (ICV), and total body water (TBW). Thirteen healthy males (mean +/- SD: age, 23 +/- 3 yr; body mass, 80.6 +/- 14.7 kg) had their TBW and ECV measured by ingesting dilution tracers (7.27 g deuterium oxide, 1.70 g sodium bromide; blood samples at 0 and 4 h). ICV was calculated as TBW minus ECV. Impedance was measured (50-500 kHz) at rest, on a nonconducting surface, with a BIS analyzer. Electrode placement, posture, exercise, food/fluid intake, and ambient temperature were controlled. Dilution measures (TBW, 51.00 +/- 9.30; ECV, 19.88 +/- 3.14; ICV, 31.12 +/- 6.80 L) and BIS volumes (TBW, 50.03 +/- 7.67; ECV, 20.95 +/- 3.33; ICV, 29.04 +/- 4.51 L) were significantly different for ECV (P < 0.01) and ICV (P < 0.05); some individual differences were large. The correlation coefficients of dilution versus BIS volumes (r = 0.93 to 0.96) were significant at P < 0.0001; SEEs were: TBW, 2.23 L; ECV, 1.26 L; and ICV, 1.71 L. We concluded that BIS is valid for between-subject comparisons of body fluid compartments, is appropriate in clinical settings where change in ECV/ICV ratio is important, and should be used by comparing the required level of accuracy to the inherent technique error/variance.
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Nine healthy subjects were studied under control conditions and following 5 mo of heavy resistance training and 5 wk of immobilization in elbow casts. Needle biopsies were taken from triceps brachii and analyzed for adenosine triphosphate (ATP), adenosine diphosphate (ADP), creatine (C), creatine phosphate (CP, and glycogen concentrations. Training resulted in an 11% increase in arm circumference and a 28% increase in maximal elbow extension strength. Immobilization resulted in decreases in arm circumference and elbow extension strength of 5% and 35%, respectively. Training also resulted in significant increases in resting concentrations of muscle creatine (by 39%), CP (by 22%), ATP (by 18%), and glycogen (by 66%). Conversely, immobilization significantly reduced CP concentration by 25% and glycogen concentration by 40%. It was concluded that heavy-resistance training results in increases in muscle energy reserves which may be reversed by a period of immobilization-induced disuse.
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Eight untrained women (F), 13 untrained men (M), and 11 male bodybuilders (BB) did maximal elbow flexions on an isokinetic dynamometer at velocities of 30, 120, 180, 240, and 300 degrees/s, from which impact torque (IT), peak torque (PT), and work (W) were measured. Biceps and total flexor cross-sectional area (CSA) were measured by computerized tomographic scanning. Muscle fiber area, fiber composition, and collagen volume density were determined from single needle biopsies of biceps brachii. Biceps fiber number was estimated as the ratio of biceps CSA (corrected for connective tissue) to mean fiber area. PT and W decreased at higher velocities in M and BB but not in F; consequently, the correlation between CSA and PT and W was lower at 300 degrees/s (r = 0.58, 0.60) than 30 degrees/s (r = 0.80, 0.79). The ratio of PT to flexor CSA was similar in all groups at 30 degrees/s, whereas F had greater ratios than M and BB at the remaining velocities. F had greater W/CSA ratios than M and BB at all velocities. IT increased at higher velocities in all groups; the increase was greater in F and M than in BB. In contrast to PT and W, the correlation between IT and CSA was greater at 300 degrees/s (r = 0.67) than 30 degrees/s (r = 0.58), and there were no differences among groups in the IT/CSA ratios. Flexor CSA correlated negatively with the ratio of IT, PT, and W to CSA. Muscle fiber composition failed to correlate with any measure of strength. M and BB had greater biceps area, fiber number, and fiber area than F.(ABSTRACT TRUNCATED AT 250 WORDS)
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Six subjects performed one-legged dynamic knee-extension. Blood samples were drawn from the femoral artery and vein, and muscle biopsies were obtained from the quadriceps muscle. Leg blood flow was measured by the thermodilution technique, and 3H-inulin was infused for determination of extra- and intracellular muscle water shifts. During the submaximal work load (S) muscle lactate increased, whereas muscle pH remained almost constant; after maximal exercise (M) the values markedly increased for lactate and decreased for pH. Except for a release of lactate from the exercising muscles, K was continuously released throughout S, and this release increased during M. Immediately when the muscles relaxed, the K release was converted to a K re-uptake. The calculated K loss, based on v- a and flow values, agreed with the decrease in muscle K content from 458 mmol/kg dw at rest to 414 mmol/kg dw at exhaustion (P less than 0.05), as analyzed on the muscle biopsies. Muscle water content increased during S mainly because of an increased extracellular H2O, whereas during M the largest increase occurred in intracellular H2O (H2Oi). Because of the simultaneous K loss and H2Oi increase in the exercising muscle the intracellular [K] was calculated to decrease from 165 mM at rest to 129 mM at exhaustion. This decrease and an increase in extracellular [K] from 4.5 mM at rest to greater than 6.0 mM at exhaustion affects the muscle membrane excitability. Muscle fatigue may thus not only be caused by changes within the cell, affecting energy metabolism or actin-myosin reaction, but may be located at the membrane protecting the cell against overload.
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There is evidence that cellular hydration state is an important factor controlling cellular protein turnover; protein synthesis and protein degradation are affected in opposite directions by cell swelling and shrinking. An increase in cellular hydration (swelling) acts as an anabolic proliferative signal, whereas cell shrinkage is catabolic and antiproliferative. The cellular hydration state is mainly determined by the activity of ion and substrate transport systems in the plasma membrane. Hormones, substrates, and oxidative stress can change the cellular hydration state within minutes, thereby affecting protein turnover. We postulate that a decrease in cellular hydration in liver and skeletal muscle triggers the protein catabolic states that accompany various diseases.
Strength and muscle characteristics were examined in biceps brachii and vastus lateralis of eight men and eight women. Measurements included motor unit number, size and activation and voluntary strength of the elbow flexors and knee extensors. Fiber areas and type were determined from needle biopsies and muscle areas by computerized tomographical scanning. The women were approximately 52% and 66% as strong as the men in the upper and lower body respectively. The men were also stronger relative to lean body mass. A significant correlation was found between strength and muscle cross-sectional area (CSA; P < or = 0.05). The women had 45, 41, 30 and 25% smaller muscle CSAs for the biceps brachii, total elbow flexors, vastus lateralis and total knee extensors respectively. The men had significantly larger type I fiber areas (4597 vs 3483 microns2) and mean fiber areas (6632 vs 3963 microns2) than the women in biceps brachii and significantly larger type II fiber areas (7700 vs 4040 microns2) and mean fiber areas (7070 vs 4290 microns2) in vastus lateralis. No significant gender difference was found in the strength to CSA ratio for elbow flexion or knee extension, in biceps fiber number (180,620 in men vs 156,872 in women), muscle area to fiber area ratio in the vastus lateralis 451,468 vs 465,007) or any motor unit characteristics. Data suggest that the greater strength of the men was due primarily to larger fibers. The greater gender difference in upper body strength can probably be attributed to the fact that women tend to have a lower proportion of their lean tissue distributed in the upper body.(ABSTRACT TRUNCATED AT 250 WORDS)
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The effect of cell-volume pertubations on mammary tissue protein synthesis has been examined. Cell-swelling, induced by a hyposmotic shock, increased the rate of incorporation of radiolabelled leucine and methionine into trichloroacetic acid precipitable material. The incorporation of radiolabel under both isosmotic and hyposmotic conditions was inhibited by cycloheximide. The increases in mammary protein synthesis as a result of cell-swelling may be attributable to an increase in casein synthesis. Conversely, cell-shrinking, as a consequence of a hyperosmotic challenge, almost abolished mammary protein (casein) synthesis. The finding that cell-volume pertubations had no significant effect on steady-state casein mRNA levels suggests that the regulation, within the time course of the experiments, is at the level of translation. The results strongly suggest that mammary cell volume may be an important cellular signal in the control of mammary protein synthesis in general and casein synthesis in particular.
Article
The purpose of this study was to test the validity of a multiple frequency bioimpedance spectroscopy (BIS) technique that estimates extracellular fluid volume (ECV), intracellular fluid volume (ICV), and total body water (TBW). Thirteen healthy males (mean +/- SD: age, 23 +/- 3 yr; body mass, 80.6 +/- 14.7 kg) had their TBW and ECV measured by ingesting dilution tracers (7.27 g deuterium oxide, 1.70 g sodium bromide; blood samples at 0 and 4 h). ICV was calculated as TBW minus ECV. Impedance was measured (50-500 kHz) at rest, on a nonconducting surface, with a BIS analyzer. Electrode placement, posture, exercise, food/fluid intake, and ambient temperature were controlled. Dilution measures (TBW, 51.00 +/- 9.30; ECV, 19.88 +/- 3.14; ICV, 31.12 +/- 6.80 L) and BIS volumes (TBW, 50.03 +/- 7.67; ECV, 20.95 +/- 3.33; ICV, 29.04 +/- 4.51 L) were significantly different for ECV (P < 0.01) and ICV (P < 0.05); some individual differences were large. The correlation coefficients of dilution versus BIS volumes (r = 0.93 to 0.96) were significant at P < 0.0001; SEEs were: TBW, 2.23 L; ECV, 1.26 L; and ICV, 1.71 L. We concluded that BIS is valid for between-subject comparisons of body fluid compartments, is appropriate in clinical settings where change in ECV/ICV ratio is important, and should be used by comparing the required level of accuracy to the inherent technique error/variance.
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This paper provides an overview of practical methods for assessing body composition of children, adults, and older adults. Three methods commonly used in field and clinical settings are skinfolds, bioelectrical impedance analysis, and anthropometry. For each method, standardized testing procedures, sources of measurement error, recommendations for technicians, and selected prediction equations for each age category are presented. The skinfold method is appropriate for estimating body fat of children (6-17 years) and body density of adults (18-60 years) from diverse ethnic groups. Likewise, bioimpedance is well suited for estimating the fat-free mass of children (10-19 years) as well as American Indian, black, Hispanic, and white adults. Anthropometric prediction equations that use a combination of circumferences and bony diameters are recommended for older adults (up to 79 years of age), as well as obese men and women.
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Nutritional status influences muscle growth and athletic performance, but little is known about the effect of nutritional supplements, such as creatine, on satellite cell mitotic activity. The purpose of this study was to examine the effect of oral creatine supplementation on muscle growth, compensatory hypertrophy, and satellite cell mitotic activity. Compensatory hypertrophy was induced in the rat plantaris muscle by removing the soleus and gastrocnemius muscles. Immediately following surgery, a group of six rats was provided with elevated levels of creatine monohydrate in their diet. Another group of six rats was maintained as a non-supplemented control group. Twelve days following surgery, all rats were implanted with mini-osmotic pumps containing the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) to label mitotically active satellite cells. Four weeks after the initial surgery the rats were killed, plantaris muscles were removed and weighed. Subsequently, BrdU-labeled and non-BrdU-labeled nuclei were identified on enzymatically isolated myofiber segments. Muscle mass and myofiber diameters were larger (P < 0.05) in the muscles that underwent compensatory hypertrophy compared to the control muscles, but there were no differences between muscles from creatine-supplemented and non-creatine-supplemented rats. Similarly, compensatory hypertrophy resulted in an increased (P < 0.05) number of BrdU-labeled myofiber nuclei, but creatine supplementation in combination with compensatory hypertrophy resulted in a higher (P < 0.05) number of BrdU-labeled myofiber nuclei compared to compensatory hypertrophy without creatine supplementation. Thus, creatine supplementation in combination with an increased functional load results in increased satellite cell mitotic activity.
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The effect of changing cell volume on rat mammary protein synthesis has been examined. Cell swelling, induced by a hyposmotic challenge, markedly increased the incorporation of radiolabelled amino acids (leucine and methionine) into trichloroacetic acid (TCA)-precipitable material: reducing the osmolality by 47% increased leucine and methionine incorporation into mammary protein by 147 and 126% respectively. Conversely, cell shrinking, induced by a hyperosmotic shock, almost abolished the incorporation of radiolabelled amino acids into mammary protein: increasing the osmolality by 70% reduced leucine and methionine incorporation into mammary protein by 86 and 93% respectively. The effects of cell swelling and shrinking were fully reversible. Volume-sensitive mammary tissue protein synthesis was dependent upon the extent of the osmotic challenge. Isosmotic swelling of mammary tissue, using a buffer containing urea (160 mM), increased the incorporation of radiolabelled leucine into TCA-precipitable material by 106%. Swelling-induced mammary protein synthesis was dependent upon calcium: removing extracellular calcium together with the addition of EGTA markedly reduced volume-activated protein synthesis. Cell swelling-induced protein synthesis was inhibited by the Ca(2+) ATPase blocker thapsigargin suggesting that volume-sensitive protein synthesis is dependent upon luminal calcium.
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The purpose of this study was to compare age and gender effects of strength training (ST) on resting metabolic rate (RMR), energy expenditure of physical activity (EEPA), and body composition. RMR and EEPA were measured before and after 24 wk of ST in 10 young men (20-30 yr), 9 young women (20-30 yr), 11 older men (65-75 yr), and 10 older women (65-75 yr). When all subjects were pooled together, absolute RMR significantly increased by 7% (5928 +/- 1225 vs 6328 +/- 1336 kJ.d-1, P < 0.001). Furthermore, ST increased absolute RMR by 7% in both young (6302 +/- 1458 vs 6719 +/- 1617 kJ x d(-1), P < 0.01) and older (5614 +/- 916 vs 5999 +/- 973 kJ x d(-1), P < 0.05) subjects, with no significant interaction between the two age groups. In contrast, there was a significant gender x time interaction (P < 0.05) for absolute RMR with men increasing RMR by 9% (6645 +/- 1073 vs 7237 +/- 1150 kJ x d(-1), P < 0.001), whereas women showed no significant increase (5170 +/- 884 vs 5366 +/- 692 kJ x d(-1), P = 0.108). When RMR was adjusted for fat-free mass (FFM) using ANCOVA, with all subjects pooled together, there was still a significant increase in RMR with ST. Additionally, there was still a gender effect (P < 0.05) and no significant age effect (P = NS), with only the men still showing a significant elevation in RMR. Moreover, EEPA and TEE estimated with a Tritrac accelerometer and TEE estimated by the Stanford Seven-Day Physical Activity Recall Questionnaire did not change in response to ST for any group. In conclusion, changes in absolute and relative RMR in response to ST are influenced by gender but not age. In contrast to what has been suggested previously, changes in body composition in response to ST are not due to changes in physical activity outside of training.
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Weight lifting, or resistance training, is a potent stimulus to the neuromuscular system. Depending on the specific program design, resistance training can enhance strength, power, or local muscular endurance. These improvements in performance are directly related to the physiologic adaptations elicited through prolonged resistance training. Optimal resistance training programs are individualized to meet specific training goals. When trained properly (i.e., similar intensity and volume), these functional and physiologic adaptations are similarly impressive among women and the aged as they are among young men. Yet, in contrast to relative measurements, sex and age differences exist in the absolute magnitude of adaptation. Of equal importance, perhaps most notably among the elderly, are the important health benefits that may also be derived from resistance training. For example, bone density, insulin sensitivity, and co-morbidities associated with obesity can be effectively managed with resistance exercise when it is conducted on a regular basis. The extent of the functional and health benefits to be accrued from resistance training depend on factors such as initial performance and health status, along with the specification of program design variables such as frequency, duration, intensity, volume, and rest intervals.
Article
To determine the effect of weight training on measures of iron status in young males and females. Forty (27 female, 13 male) non-weight-trained college age subjects participated in a 12-wk weight-training program conducted 3 d.wk-1. Blood samples and food diaries were obtained pretraining and at 4-wk intervals. Blood was analyzed for hemoglobin, hematocrit, serum iron (SI), total iron binding capacity (TIBC), transferrin saturation (TS), serum ferritin (SF), soluble transferrin receptor (sTfR), and creatine kinase (CK). Subjects were grouped by SF level (FL, females < or = 20 microg.L-1; FN, females > 20 microg.L-1; ML, males < or = 45 microg.L-1; MN, males > or = 50 microg.L-1) to determine the impact of initial iron status on measured responses. Weight training increased strength and fat-free mass and decreased levels of percent body fat. Hemoglobin concentration declined after 12 wk of training (13.7 +/- 1.6 vs 13.2 +/- 1.7 g.dL-1), independent of gender or initial iron status. Only the MN group experienced a decline in SF level after 8 wk of training (129.7 +/- 77.9 vs 102.0 +/- 57.8 microg.L-1). No significant changes were observed for hematocrit, SI, TIBC, TS, sTfR, or CK measures. Total iron intake, but not heme or bioavailable iron intakes, declined at the 12th week of training compared with baseline (13.4 +/- 6.5 vs 10.7 +/- 4.8 mg.d-1) and was not significantly correlated with hematological or iron status measures. Hemoglobin concentration declines without alterations in SI, TIBC, TS, or sTfR after 12 wk of weight training. The SF level of males with adequate iron status is lowered with weight training but not among females or males with low iron status.
Article
To assess the influences of age and sex on regional changes in 1 repetition maximum (1RM) strength, 10 young men (20-30 years), 8 young women (20-30 years), 11 older men (65- 75 years), and 10 older women (65-75 years) were studied before and after a 24-week whole-body strength training program. Changes in 1RM strength were analyzed for each individual exercise, as well as by calculating a total body score (TBS), an upper body score (UBS), and a lower body score (LBS). The effect of age and sex on changes in 1RM strength was analyzed using a repeated measures analysis of variance. When changes in strength for individual exercises were analyzed, the chest press, lat pulldown, shoulder press, and triceps pushdown were affected by both age (p < 0.05) and sex (p < 0.05), while the biceps curls were only influenced by age (p < 0.05). For the lower body, the leg press changes in 1RM strength were influenced by age (p < 0.0001), while leg extension was influenced by sex (p < 0.05). Total body score, UBS, and LBS showed significant increases with 24 weeks of ST (p < 0.001, all). Changes in TBS and UBS were affected by age (p < 0.001, both) and sex (p < 0.05 and p < 0.001, respectively). Younger subjects showed a greater increase in strength than older subjects, and men showed a greater increase in strength compared with women. Changes in LBS were affected by age (p < 0.001), with younger subjects showing a greater increase in strength compared with the older subjects, but not by sex (p = 0.464). These data indicate that regional increases in strength are differentially affected by age and sex.
Article
Women oxidize more lipid and less carbohydrate and protein compared with men during endurance exercise. The increase in fat oxidation is associated with higher intramyocellular lipid content and use as well as greater adipocyte lipolysis. Glucose rates of appearance and disappearance are lower for women than for men, with no change in basal muscle glycogen, and some evidence for muscle glycogen sparing during endurance exercise. Women oxidize less protein compared with men and show lower leucine oxidation during exercise. The consistent and robust finding of higher mRNA abundance for most components of fat-oxidation pathways in women compared with men is directionally consistent with the substrate-oxidation data. A lack of directional consistency between mRNA species involved in carbohydrate and protein metabolism and the known sex differences during exercise implies that fat oxidation is regulated and that carbohydrate and protein oxidation follow by metabolic demand. Administration of 17-beta-estradiol to men recapitulates most of the described sex differences in metabolism and mRNA content. The greater fat oxidation for women during submaximal endurance exercise compared with men seems to occur partly through a sex hormone-mediated enhancement of lipid-oxidation pathways.
Performance and physiologic adaptations to resistance training Expression of aquaporin-4 in fast-twitch fibers of mammalian skeletal muscle Regulation of protein synthesis in lactating rat mam-mary tissue by cell volume
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Variability in muscle size and strength gain after unilateral resistance training
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Changes in body composition, body build and performance associated with different weight training frequencies in males and females. National Strength and Conditioning Association
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