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1.
PLoS One ; 15(8): e0227394, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866148

RESUMO

The aim of this study was to assess the impact of a 6-week specialized training program aimed at strengthening core muscles to improve the effectiveness of selected elements of a swimming race on a group of Polish swimmers. Sixteen male national level swimmers (21.6 ± 2.2 years) participated in the research. The competitors were randomly assigned to 1 of 2 groups before the data collection process: an experimental (EG, n = 8) and a control (CG, n = 8) group. Both groups of swimmers underwent the same training program in the water environment (volume and intensity), while swimmers from the EG additionally performed specific core muscle training. The task of the swimmers was an individual front crawl swim of 50 m, during which the kinematic parameters of the start jump, turn and swimming techniques were recorded using a video camera system. In both groups, a minor increase in the flight phase was observed at the start (EG = 0.06 m, 1.8%; p = 0.088; CG = 0.08 m, 2.7%; p = 0.013). The time to cover a distance of 5 m after the turn and the recorded average speed in swimming this distance for the EG statistically significantly improved by 0.1 s (-28.6%; p < 0.001) and 3.56 m∙s-1 (23.2%; p = 0.001), respectively. In the EG, a statistically significant improvement in 50 m front crawl swimming performance of 0.3 s (-1.2%, p = 0.001) was observed. The results of the research show that the implementation of isolated strengthening of the stabilizing muscles seems to be a valuable addition to the standard training of swimmers.


Assuntos
Exercício Físico/fisiologia , Condicionamento Físico Humano/métodos , Natação/fisiologia , Desempenho Atlético/fisiologia , Fenômenos Biomecânicos , Terapia por Exercício , Humanos , Masculino , Força Muscular/fisiologia , Músculos , Polônia , Treinamento de Resistência/métodos , Adulto Jovem
2.
Nat Commun ; 11(1): 4479, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32900999

RESUMO

The giant protein titin is thought to be required for sarcomeric integrity in mature myocytes, but direct evidence for this hypothesis is limited. Here, we describe a mouse model in which Z-disc-anchored TTN is depleted in adult skeletal muscles. Inactivation of TTN causes sarcomere disassembly and Z-disc deformations, force impairment, myocyte de-stiffening, upregulation of TTN-binding mechanosensitive proteins and activation of protein quality-control pathways, concomitant with preferential loss of thick-filament proteins. Interestingly, expression of the myosin-bound Cronos-isoform of TTN, generated from an alternative promoter not affected by the targeting strategy, does not prevent deterioration of sarcomere formation and maintenance. Finally, we demonstrate that loss of Z-disc-anchored TTN recapitulates muscle remodeling in critical illness 'myosinopathy' patients, characterized by TTN-depletion and loss of thick filaments. We conclude that full-length TTN is required to integrate Z-disc and A-band proteins into the mature sarcomere, a function that is lost when TTN expression is pathologically lowered.


Assuntos
Fibras Musculares Esqueléticas/fisiologia , Proteínas Quinases/fisiologia , Sarcômeros/fisiologia , Animais , Fenômenos Biomecânicos , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Eletrônica de Transmissão , Força Muscular/fisiologia , Atrofia Muscular/etiologia , Atrofia Muscular/patologia , Atrofia Muscular/fisiopatologia , Doenças Musculares/patologia , Doenças Musculares/fisiopatologia , Miosinas/metabolismo , Proteínas Quinases/deficiência , Proteínas Quinases/genética , Sarcômeros/patologia , Ubiquitinação
3.
Medicine (Baltimore) ; 99(38): e22131, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32957334

RESUMO

INTRODUCTION: In activities involving upper limbs, patients with chronic obstructive pulmonary disease (COPD) report an increase in dyspnea. For this reason, the authors of the recommendations about pulmonary rehabilitation propose to perform upper limbs muscle strengthening in patients with COPD. However, the modalities of strengthening are not clearly established.The aim of this study is to compare the effects of upper limbs endurance strengthening versus upper limbs force strengthening, in patients with COPD during a pulmonary rehabilitation program. METHODS: This study is a randomized, open-label, bi-center controlled trial in parallel groups distributed in a ratio (1:1) comparing upper limbs force strengthening (group F) to the upper limbs endurance strengthening (group E) during a pulmonary rehabilitation program in patients with COPD stages 2 to 4 (A-D).After randomization, patients will be allocated to follow: A 4 weeks pulmonary rehabilitation program with upper limbs resistance strengthening (group F). A 4 weeks pulmonary rehabilitation program with upper limbs endurance strengthening (group E).The primary outcome is dyspnea measured with the London Chest Activity of daily Living questionnaire. The secondary outcomes are dyspnea (using Modified Medical Research Council dyspnea Scale, dyspnea-12 questionnaire, multidimensional dyspnea profile questionnaire), upper limb exercise capacity (using the 6-minute Peg Board and Ring Test), Maximal voluntary strength of deltoid, biceps, and brachial triceps.The sample size calculated is 140 patients per group, or 280 in total. DISCUSSION: The modalities of upper limb strengthening are not very well known, and evidence based is lacking to recommend endurance or resistance upper limb strengthening.We anticipate that the results of this study will be of relevance to clinical practice. They will bring information about the best modality of upper limb strengthening to use during a pulmonary rehabilitation program. TRIAL REGISTRATION: IdRCB n°2018-A00955-50; V1.1 du 11/07/2018; REHABSUP, clinical trial.gov (NCT03611036), registered August 02, 2018, https://clinicaltrials.gov/ct2/show/NCT03611036.


Assuntos
Dispneia/reabilitação , Doença Pulmonar Obstrutiva Crônica/reabilitação , Treinamento de Resistência/métodos , Extremidade Superior , Dispneia/fisiopatologia , Humanos , Estudos Multicêntricos como Assunto , Força Muscular/fisiologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Ensaios Clínicos Controlados Aleatórios como Assunto
4.
Geriatr Gerontol Int ; 20(10): 899-903, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32886828

RESUMO

AIM: Exercise therapy is a key intervention in the management of knee osteoarthritis (OA). This study aimed to test the 6-month effectiveness of Wu Qin Xi Qigong (WQXQ) exercise versus a conventional physical therapy (control group [CG]) on physical functioning in patients with early knee OA. METHODS: This study was a 6-month follow-up from a randomized controlled trial. Participants with knee OA were randomly allocated to the WQXQ or CG. Data from the Berg Balance Scale, Timed Up and Go Test, 6-Minute Walk Test, 30-Second Chair Stand Test, the Western Ontario and McMaster Universities Osteoarthritis Index, knee extension strength and knee flexion strength were collected before and after the 6-month intervention. RESULTS: Both treatment groups demonstrated large (20%-50%) and clinically relevant reductions in activity limitations, pain and knee instability, which were sustained at 6 months post-treatment. No differences in effectiveness between experimental and control treatment were found on Timed Up and Go Test, 6-Minute Walk Test, knee extension strength and knee flexion strength except for a higher Berg Balance Scale score (P = 0.029) and lower Western Ontario and McMaster Universities Osteoarthritis Index pain score (P = 0.031) in the WQXQ group. CONCLUSIONS: Both WQXQ and conventional physical therapy exercise programs were highly effective in reducing activity limitations and pain, and promoting balance and muscle power. WQXQ was found to be more effective in promoting balance and reducing pain than conventional physical therapy exercise in patients with knee OA. Geriatr Gerontol Int 2020; 20: 899-903.


Assuntos
Osteoartrite do Joelho/terapia , Modalidades de Fisioterapia , Qigong/métodos , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , China , Terapia por Exercício , Feminino , Humanos , Articulação do Joelho/fisiologia , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Dor/reabilitação , Manejo da Dor/métodos , Medição da Dor , Equilíbrio Postural/fisiologia , Estudos de Tempo e Movimento , Resultado do Tratamento
5.
Geriatr Gerontol Int ; 20(10): 980-987, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32886834

RESUMO

AIMS: Sarcopenia is a serious problem because of its poor prognosis. Growth differentiation factor 15 (GDF15) is associated with mitochondrial dysfunction, inflammation, insulin resistance and oxidative stress, which may play crucial roles for the development of sarcopenia. We aimed to examine whether serum GDF15 level is associated with muscle mass, strength and lower extremity function in older patients with cardiometabolic disease. METHODS: Serum GDF15 levels were measured in 257 patients with cardiometabolic diseases (including 133 patients with diabetes) who had visited the frailty clinic, using a latex turbidimetric immunoassay. Appendicular skeletal muscle index, handgrip strength, timed-up-and-go test and gait speed were evaluated. Power, speed, balance and total scores based on the sit-to-stand test were calculated to assess lower extremity function. RESULTS: The highest tertile of serum GDF15 was independently associated with low handgrip strength, low gait speed, long timed-up-and-go time and scores of lower extremity function but not an appendicular skeletal muscle index in multiple logistic regression analyses after adjustment for covariates. Patients in the highest tertile of GDF15 were at the risk of having three to nine times lower grip strength, three times lower gait speed, five to six times lower mobility and five to 11 times reduction in lower extremity function as compared with those in the lowest GDF15 tertile dependent on the models. CONCLUSIONS: Elevated serum GDF15 level was independently associated with low muscle strength and lower extremity function in older patients with cardiometabolic disease. Serum GDF15 could be one of the biomarkers for muscle weakness and low physical performance. Geriatr Gerontol Int 2020; 20: 980-987.


Assuntos
Doenças Cardiovasculares/sangue , Diabetes Mellitus/sangue , Fator 15 de Diferenciação de Crescimento/sangue , Extremidade Inferior/fisiopatologia , Força Muscular/fisiologia , Sarcopenia/sangue , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Doenças Cardiovasculares/fisiopatologia , Diabetes Mellitus/fisiopatologia , Feminino , Fragilidade , Força da Mão , Humanos , Masculino , Músculo Esquelético/fisiopatologia , Sarcopenia/fisiopatologia , Estudos de Tempo e Movimento , Velocidade de Caminhada/fisiologia
6.
J Frailty Aging ; 9(4): 214-218, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32996557

RESUMO

BACKGROUND: It is known that maintenance of muscle mass cannot prevent loss of muscle strength in older adults. Recent evidence suggests that fat mass can weaken the relationship between muscle mass and functional performance. No information exists if fat mass can independently affect muscle strength and jump test performance in middle-aged and older adults. OBJECTIVE: To assess the independent relationships between fat mass, leg muscle mass, lower extremity muscle strength, and jump test performance in adults, 55-75 years of age. DESIGN: Cross-sectional. SETTING: University laboratory. PARTICIPANTS: Fifty-nine older adults (men, n = 27, age = 64.8 ± 6.5 years; women, n = 32, age = 62.5 ± 5.1 years) participated in this study. MEASUREMENTS: Dual energy X-ray absorptiometry was used to measure fat mass and leg muscle mass. An average of 3 maximal countermovement jumps was used to calculate jump power and jump height. Two leg press and hip abduction strength were assessed by 1-repetition maximum testing. RESULTS: Stepwise sequential regression analysis of fat mass and leg muscle mass versus jump test performance and measures of muscle strength after adjusting for age, height, and physical activity revealed that fat mass was negatively associated with jump height (p = 0.047, rpartial = -0.410) in men. In women, fat mass was negatively associated with jump height (p = 0.003, rpartial = -0.538), leg press (p = 0.002, rpartial = -0.544), and hip abduction strength (p < 0.001, rpartial = -0.661). Leg muscle mass was positively associated with jump power in women (p = 0.047, rpartial = 0.372) only. CONCLUSIONS: Fat mass has an independent negative relationship with jump test performance in middle-aged and older men and women. This has clinical implications for rehabilitating neuromuscular performance in middle-aged and older adults.


Assuntos
Tecido Adiposo/fisiologia , Teste de Esforço , Força Muscular/fisiologia , Desempenho Físico Funcional , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
7.
Am J Phys Med Rehabil ; 99(10): 902-908, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32941253

RESUMO

OBJECTIVE: The aim of the study was to explore an individualized sonographic muscle thickness ratio and its cutoff values in the diagnosis of sarcopenia. DESIGN: A total of 326 community-dwelling adults were included in this cross-sectional study. Total skeletal muscle mass was evaluated by bioelectrical impedance analysis, and nine-site muscle thickness measurements using ultrasound. Isometric handgrip and knee extension strengths were assessed. Physical performance was evaluated by usual Gait Speed, Chair Stand Test, and Timed Up and Go Test. RESULTS: Because the anterior thigh muscle thickness was the most significantly decreasing measurement with aging and the most significantly related value with body mass and height; sonographic thigh adjustment ratio was calculated by dividing it with body mass index. Using the two standard deviation values of our healthy young adults, sonographic thigh adjustment ratio cutoff values were found as 1.4 and 1.0 for male and female subjects, respectively. Sonographic thigh adjustment ratio values were negatively correlated with Chair Stand Test and Timed Up and Go Test in both sexes (all P < 0.05) and positively correlated with gait speed in female subjects and knee extension strength in male subjects (both P < 0.05). CONCLUSIONS: Our results imply that regional (rather than total) muscle mass measurements should be taken into consideration for the diagnosis of sarcopenia.


Assuntos
Sarcopenia/diagnóstico por imagem , Coxa da Perna/diagnóstico por imagem , Ultrassonografia/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Diagnóstico Diferencial , Impedância Elétrica , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia
8.
PLoS One ; 15(8): e0230224, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764766

RESUMO

The term "oral frailty" reflects the fact that oral health is associated with physical frailty and mortality. The gold standard methods for evaluating the swallowing function have several problems, including the need for specialized equipment, the risk of radiation exposure and aspiration, and general physicians not possessing the requisite training to perform the examination. Hence, several simple and non-invasive techniques have been developed for evaluating swallowing function, such as those for measuring tongue pressure and tongue thickness. The aim of this study was to investigate the relationship between tongue thickness ultrasonography and tongue pressure in the Japanese elderly. We evaluated 254 elderly patients, who underwent tongue ultrasonography and tongue pressure measurement. To determine tongue thickness, we measured the vertical distance from the surface of the mylohyoid muscle to the tongue dorsum using ultrasonography. The results of the analyses revealed that tongue thickness was linearly associated with tongue pressure in both sexes. In male participants, dyslipidemia, lower leg circumference, and tongue pressure were independently and significantly associated with tongue thickness. In female participants, body mass index and tongue pressure were independently and significantly associated with tongue thickness. The optimal cutoff for tongue thickness to predict the tongue pressure of < 20 kPa was 41.3 mm in males, and 39.3 mm in females. In the Japanese elderly, tongue thickness using ultrasonography is associated with tongue pressure. Tongue thickness and tongue pressure, which are sensitive markers for oral frailty, decrease with age. We conclude that tongue ultrasonography provides a less invasive technique for determining tongue thickness and predicts oral frailty for elderly patients.


Assuntos
Deglutição/fisiologia , Língua/fisiologia , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Feminino , Fragilidade , Humanos , Japão , Masculino , Força Muscular/fisiologia , Saúde Bucal , Pressão , Ultrassonografia/métodos
9.
Neuron ; 107(3): 580-589.e6, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32778224

RESUMO

To induce brain plasticity in humans, we casted the dominant upper extremity for 2 weeks and tracked changes in functional connectivity using daily 30-min scans of resting-state functional MRI (rs-fMRI). Casting caused cortical and cerebellar regions controlling the disused extremity to functionally disconnect from the rest of the somatomotor system, while internal connectivity within the disused sub-circuit was maintained. Functional disconnection was evident within 48 h, progressed throughout the cast period, and reversed after cast removal. During the cast period, large, spontaneous pulses of activity propagated through the disused somatomotor sub-circuit. The adult brain seems to rely on regular use to maintain its functional architecture. Disuse-driven spontaneous activity pulses may help preserve functionally disconnected sub-circuits.


Assuntos
Córtex Motor/diagnóstico por imagem , Plasticidade Neuronal/fisiologia , Restrição Física , Atividades Cotidianas , Moldes Cirúrgicos , Feminino , Lateralidade Funcional , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Motor/fisiologia , Destreza Motora/fisiologia , Força Muscular/fisiologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Extremidade Superior
10.
PLoS One ; 15(8): e0237921, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841300

RESUMO

Power declines at a greater rate during ageing and is more relevant for functional deterioration than either loss of maximum strength or muscle mass. Human movement typically consists of stretch-shortening cycle action. Therefore, plyometric exercises, using an eccentric phase quickly followed by a concentric phase to optimize power production, should resemble daily function more than traditional resistance training, which primarily builds force production capacity in general. However, it is unclear whether older adults can sustain such high-impact training. This study compared the effects of plyometric exercise (PLYO) on power, force production, jump and functional performance to traditional resistance training (RT) and walking (WALK) in older men. Importantly, feasibility was investigated. Forty men (69.5 ± 3.9 years) were randomized to 12-weeks of PLYO (N = 14), RT (N = 12) or WALK (N = 14). Leg press one-repetition maximum (1-RM), leg-extensor isometric maximum voluntary contraction (MVC) and rate of force development (RFD), jump and functional performance were evaluated pre- and post-intervention. One subject in RT (low back pain) and three in PLYO (2 muscle strains, 1 knee pain) dropped out. Adherence to (91.2 ± 4.4%) and acceptability of (≥ 7/10) PLYO was high. 1-RM improved more in RT (25.0 ± 10.0%) and PLYO (23.0 ± 13.6%) than in WALK (2.9 ± 13.7%) (p < 0.001). PLYO improved more on jump height, jump power, contraction time of jumps and stair climbing performance compared to WALK and/or RT (p < 0.05). MVC improved in RT only (p = 0.028) and RFD did not improve (p > 0.05). To conclude, PLYO is beneficial over RT for improving power, jump and stair climbing performance without compromising gains in strength. This form of training seems feasible, but contains an inherent higher risk for injuries, which should be taken into account when designing programs for older adults.


Assuntos
Locomoção/fisiologia , Força Muscular/fisiologia , Exercício Pliométrico , Treinamento de Resistência , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos de Viabilidade , Humanos , Masculino , Reprodutibilidade dos Testes , Caminhada
11.
J Sports Sci ; 38(17): 1936-1942, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32731786

RESUMO

We performed a randomized, controlled trial to analyse the effects of resistance training (RT) on cognitive and physical function among older adults. Fifty participants (mean age 67 years, ~60% woman) were randomly assigned to an RT program or a control group. Participants allocated to RT performed three sets of 10-15RM in nine exercises, three times per week, for 12-weeks. Control group did not perform any exercise. Variables included cognitive (global and executive function) and physical function (gait, mobility and strength) outcomes. At completion of the intervention, RT was shown to have significantly mitigated the drop in selective attention and conflict resolution performance (Stroop test: -494.6; 95%CI: -883.1; -106.1) and promoted a significant improvement in working memory (digit span forward: -0.6; 95%CI: -1.0; -0.1 and forward minus backward: -0.9; 95% CI: -1.6; -0.2) and verbal fluency (animal naming: +1.4, 95%CI 0.3, 2.5). No significant between-group differences were observed for other cognitive outcomes. Regarding physical function, at completion of the intervention, the RT group demonstrated improved fast-pace gait performance (-0.3; 95% CI: -0.6; -0.0) and 1-RM (+21.4 kg; 95%CI: 16.6; 26.2). No significant between-group differences were observed for other mobility-related outcomes. In conclusion, RT improves cognitive and physical function of older adults.


Assuntos
Cognição/fisiologia , Desempenho Físico Funcional , Treinamento de Resistência , Idoso , Função Executiva/fisiologia , Feminino , Marcha/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Força Muscular/fisiologia , Treinamento de Resistência/métodos
12.
PLoS One ; 15(7): e0235734, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32667956

RESUMO

OBJECTIVE: The objective of this randomized controlled trial was to examine dynamic balance changes (reach distance) in middle-aged adults using the Y Balance Test (YBT) following 8 weeks of home-based exercise program adapted from the Otago Exercise Program (OEP). METHODS: Fifty-two healthy middle-aged adults with mean age of 54.4±5.4 years and body mass index of 27.7±5.7 kg/m2 were randomly assigned into either the exercise group (a modification of the Otago Exercise Program, that consisted of home-based balance and strength exercises) or the non-exercise group (continuation of usual lifestyle) by having the participants select a paper from a sealed envelope. The YBT was used to measure participants' dynamic balance in the right and left anterior (RA, LA), posteromedial (RPM, LPM), and posterolateral (RPL, LPL) directions. RESULTS: The outcome in this trial was reach distance (cm). There was a significant group by time interaction in terms of reach distance for all directions (p<0.05, η2 ranged from 0.06 to 0.20). In the exercise group, results of the repeated measures analysis of variance (ANOVA) showed significant improvements in the reach distance in all the directions (p<0.001). In contrast, the non-exercise group had significant difference only in the left posterolateral direction (p = 0.009). Participants in the exercise group achieved significantly greater reach distance (cm) (95% confidence interval (CI)) for RA[(2.8, 0.4 to 5.2), p = 0.023]; LA[(3.2, 0.9 to 5.6), p = 0.008]; RPM[(4.0, 1.0 to 7.9), p = 0.046]; LPM[(5.8,1.3 to 10.3), p = 0.013]; RPL[(7.6, 2.6 to 12.6), p = 0.003]; and LPL[(4.2, 0.3 to 8.2), p = 0.035]. CONCLUSION: The modified version of OEP appears to be effective in improving parameters of dynamic balance in the middle-aged adult population. The improvements in YBT reach distance in the exercise group are indicative of the significance of performing balance and strength exercises regularly for this population.


Assuntos
Acidentes por Quedas/prevenção & controle , Exercício Físico , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
13.
PLoS One ; 15(6): e0235377, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603351

RESUMO

The purpose of this study was to investigate whether a six-week, twice weekly resistance training (4 sets at 30% 1-RM until failure) with practical blood flow restriction (BFR) using 7cm wide cuffs with a twist lock placed below the patella is superior to training without BFR (NoBFR) concerning muscle mass and strength gains in calf muscles. A two-group (BFR n = 12, mean age 27.33 (7.0) years, training experience 7.3 (7.0) years; NoBFR n = 9, mean age 28.9 (7.4) years, training experience 7.1 (6.6) years) randomized matched pair design based on initial 1-RM was used to assess the effects on structural and functional adaptations in healthy males (Perometer calf volume [CV], gastrocnemius muscle thickness using ultrasound [MT], 7-maximal hopping test for leg stiffness [LS], 1-RM smith machine calf raise [1-RM], and visual analogue scale as a measure of pain intensity [VAS]). The mean number of repetitions completed per training session across the intervention period was higher in the NoBFR group compared to the BFR group (70 (16) vs. 52 (9), p = 0.002). VAS measured during the first session increased similarly in both groups from first to fourth set (p<0.001). No group effects or time×group interactions were found for CV, MT, LS, and 1-RM. However, there were significant time effects for MT (BFR +0.07 cm; NoBFR +0.04; p = 0.008), and 1-RM (BFR +40 kg; NoBFR +34 kg; p<0.001). LS and CV remained unchanged through training. VAS in both groups were similar, and BFR and NoBFR were equally effective for increasing 1-RM and MT in trained males. However, BFR was more time efficient, due to lesser repetition per training session.


Assuntos
Adaptação Fisiológica , Força Muscular/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Adulto , Humanos , Masculino , Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Adulto Jovem
14.
PLoS One ; 15(7): e0236266, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32726351

RESUMO

The aim of this study was an evaluation of the musculoskeletal system in women and men with Generalized Joint Hypermobility (GJH). The study included 87 participants- 40 with Generalized Joint Hypermobility (aged 21.2 ±1.8 years) and 47 (aged 21.0 ±1.3 years) in the control group (CG). The study included the Beighton score, the measurements of body composition, muscle flexibility (Straight Leg Raise test, Popliteal Angle test, Modified Thomas Test), and the measurements of muscle strength and muscle power. T-test and Mann-Whitney U Test were applied to assess the differences between independent groups. The study showed that there were no significant differences (p>.05) in the assessed body composition and the muscle flexibility between both women and men with GJH and the participants in the CG. Under isokinetic conditions for the non-dominant lower extremity, men from the CG received significantly higher (p = .02) flexion peak torque at 180°/s angular velocity. Women from the CG received a statistically significantly lower (p = .04) F/E ratio at 180°/s velocity. Under isometric conditions for both women and men with GJH, there were no statistically significant differences (p>.05) in the maximum torques in knee extension and flexion compared to the CG. For women and men with GJH, the maximum power in the lower extremities and jumping ability were not significantly different (p>.05) compared to the CG participants. The body composition, muscle flexibility, muscle strength, and muscle power of adults with Generalized Joint Hypermobility did not differ compared to healthy participants. The fact that there are no differences does not exclude the efficacy of strength training in increasing levels of muscle strength and its impact on body posture and proprioception or coordination.


Assuntos
Instabilidade Articular/fisiopatologia , Articulação do Joelho/fisiopatologia , Força Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Adulto , Composição Corporal/fisiologia , Feminino , Humanos , Instabilidade Articular/epidemiologia , Extremidade Inferior/fisiopatologia , Masculino , Amplitude de Movimento Articular/fisiologia , Adulto Jovem
15.
PLoS One ; 15(7): e0235952, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649708

RESUMO

BACKGROUND: Dietary protein supplementation combined with resistance exercise (RE) may counteract declines in muscle strength, mass, and function (sarcopenia), but the role of whole foods rich in protein, such as milk, is less well understood. In the MIlkMAN study, we aimed to examine the feasibility and acceptability of milk+RE as an intervention for muscle function in community-dwelling older adults, and provide exploratory pilot data for future substantive research in population at risk of sarcopenia. METHODS: In a parallel groups design, 30 older adults (71.7±3.6 years; 12 women) were randomised into three groups: WM (whole milk 3.6% fat)+RE, SM (skimmed milk 0.3% fat)+RE, and C (isocaloric carbohydrate drink)+RE. RE was performed twice-weekly over 6 weeks in a community gym, followed by the consumption of 500 ml of milk (~20 g protein) or carbohydrate drink immediately after exercise and a further 500 ml at home within the following 4-5 hours. The feasibility and acceptability of the study was determined by calculating recruitment and attendance rates, compliance with the intervention, rating participants' experiences, and recording adverse health events. RESULTS: The response rate was 49% (out of 400 invitations sent), and the recruitment rate was 73.2% (30 participants recruited out of 41 screened for eligibility). Twenty-nine participants completed the intervention-an attendance rate of 97.1%; 89.7% rated their experience as 'excellent'/very good'. Compliance with taking the drinks was 97.1% (WM), 98.3% (SM), and 95.0% (C); 93.1% rated their drink intake as 'easy'/'very easy' with no adverse effects. Collection of exploratory pilot data to inform future trials was successful. Mean change in grip strength, 5-chair rises, and gait speed were 0.9±3.4 kg, 1.8±2.2 s, 0.1±0.1 m/s, respectively with no differences between the groups. CONCLUSIONS: This community-based milk+RE intervention was feasible and acceptable to older adults. The study successfully collected pilot data for future substantive research.


Assuntos
Exercício Físico , Leite , Força Muscular/fisiologia , Idoso , Animais , Suplementos Nutricionais , Estudos de Viabilidade , Feminino , Humanos , Vida Independente , Masculino , Projetos Piloto , Qualidade de Vida , Treinamento de Resistência
16.
PLoS One ; 15(7): e0235679, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645095

RESUMO

INTRODUCTION: Static stretching (SS) program are widely used in clinical and athletic settings. Many previous studies investigate the effect of SS program on muscle strength and muscle architecture (muscle thickness, and pennation angleh). However, no consensus has been reached about the effect of SS programs on muscle strength and muscle architecture. The aim of this study was to investigate the effects of 6-week SS programs performed at different weekly frequencies on muscle strength, muscle thickness and pennation angle at different ankle joint positions. METHODS: A total of 24 healthy male volunteers were performed 6-week SS programs (2,160 s of SS: 360 s/week*6 weeks) and were randomized to a group that performed SS once a week, or a group that performed SS three times per week. Total time under stretching was equated between groups. The muscle strength (maximum voluntary isometric contraction) at three different ankle joints were assessed before and after the 6-week SS program. In addition, muscle thickness and pennation angle were assessed by ultrasonography before and after 6-week SS program. RESULTS: There were no significant changes in all variables before and after the 6-week SS program, regardless of weekly frequency (p > 0.05). CONCLUSIONS: Our results suggest that 6-week SS programs do not increase muscle strength or muscle architecture at different ankle joint positions, regardless of stretching frequency; however, no negative effect on these outcomes was observed, contrary to evidence on the immediate, detrimental effects of SS.


Assuntos
Força Muscular/fisiologia , Exercícios de Alongamento Muscular , Músculo Esquelético , Articulação do Tornozelo , Humanos , Masculino , Exercícios de Alongamento Muscular/efeitos adversos , Exercícios de Alongamento Muscular/métodos , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia , Amplitude de Movimento Articular/fisiologia , Ultrassonografia , Adulto Jovem
17.
Artigo em Inglês | MEDLINE | ID: mdl-32645967

RESUMO

Myostatin A55T genotype is one of the candidates showing inter-individual variation in skeletal muscle phenotypes. The aim of this study was to investigate the effect of the myostatin A55T genotype on markers of muscle damage after eccentric exercise. Forty-eight young, healthy male college students (age = 24.8 ± 2.2 years, height = 176.7 ± 5.3 cm, weight = 73.7 ± 8.3 kg) were enrolled in this study, and muscle damage was induced through 50 reps of maximal eccentric muscle contraction. As markers of muscle damage, maximal isometric strength (MIS), muscle soreness, creatine kinase (CK), and aspartate transaminase (AST) were measured. Myostatin A55T genotypes were classified into homozygous myostatin A55T allele (AA, n = 34, 72%), heterozygous myostatin A55T allele (AT, n = 13, 26%), and homozygous mutant carriers (TT, n = 1, 2%). After eccentric exercise, the subjects with heterozygous for AT showed markedly quicker MIS recovery compared to the AA group (p = 0.042). However, there were no significant variations in muscle soreness (p = 0.379), CK (p = 0.955), and AST (p = 0.706) among the groups. These results suggest that AT in myostatin A55T genotype may be associated with quicker strength recovery following exercise-induced muscle damage.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Exercício Físico/fisiologia , Força Muscular/fisiologia , Mialgia/etiologia , Miostatina/genética , Genótipo , Humanos , Masculino , Contração Muscular/genética , Contração Muscular/fisiologia , Força Muscular/genética , Músculo Esquelético/fisiologia , Polimorfismo de Nucleotídeo Único , Recuperação de Função Fisiológica , Treinamento de Resistência
18.
PLoS One ; 15(7): e0236663, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32726364

RESUMO

This study assessed the efficacy of strength training using augmented eccentric loading to provoke increases in leg strength in well-trained athletes, and sprint track cyclists, using a novel leg press device. Twelve well-trained athletes were randomly allocated traditional resistance training (TRAD, n = 6), or resistance training using augmented eccentric loading (AEL, n = 6). A further 5 full-time, professional sprint track cyclists from a senior national squad programme also trained with augmented eccentric loading (AEL-ATH) alongside their usual sport-specific training. Participants completed four weeks of twice-weekly resistance training using the leg press exercise. In TRAD the lowering phase of the lift was set relative to concentric strength. In AEL and AEL-ATH the lowering phase was individualised to eccentric strength. Concentric, eccentric, isometric and coupled eccentric-concentric leg press strength, and back squat 1 repetition maximum (1RM), were assessed pre- and post-training. The AEL and AEL-ATH groups performed the eccentric phase with an average 26 ± 4% greater load across the programme. All groups experienced increases in concentric (5%, 7% and 3% for TRAD, AEL & AEL-ATH respectively), eccentric (7%, 11% and 6% for TRAD, AEL & AEL-ATH respectively), and squat 1RM (all p < 0.05), where the AEL-ATH group experienced relatively greater increases (13% vs. 5% in TRAD and AEL, p < 0.01). The TRAD and AEL groups also increased isometric strength (p < 0.05). A four-week period of augmented eccentric loading increased leg strength in well-trained athletes and track cyclists. The eccentric leg press stimulus was well-tolerated, supporting the inclusion of such training in the preparation programmes of athletes.


Assuntos
Bandagens Compressivas , Força Muscular/fisiologia , Treinamento de Resistência , Adulto , Atletas , Feminino , Humanos , Masculino , Adulto Jovem
19.
Hu Li Za Zhi ; 67(3): 48-55, 2020 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-32495329

RESUMO

BACKGROUND: Falls are a very common problem in older adults. Improving lower extremity muscle strength is the primary objective of fall-prevention programs. PURPOSE: The aim of the study was to evaluate the effects of the Otago Exercise Program (OEP) on the lower extremity muscle strength of residents living in a long-term care institution. METHODS: In this repeated measurement study, participants were allocated into either the experimental group (EG) or the control group (CG). All of the participants maintained normal activities, and EG participants were additionally enrolled in a 6-month group OEP led by a physiotherapist. The OEP, comprising warm-up exercises, strength training, balance training, and walking training, requires about 45 minutes per session, 3 times a week. A total of 78 OEP sessions were performed during the 6-month intervention. A 30-Second Sit-to-Stand Test and lower extremity muscle strength measurements were performed at baseline, after 3 months, and after 6 months. RESULTS: The twenty participants in this study had a mean age over 80 years and were recruited from a long-term care institution in southern Taiwan. There were ten participants in each group, and the mean total OEP session attendance for EG participants was 92.8%. Although the EG had lower extremity muscle strength than the CG at baseline, the EG had achieved significant improvements in the muscle strength values for the knee extensor, knee flexor, ankle plantar flexors, and dorsiflexors after 6 months (group x time interaction, p < .05). In addition, the results of the 30-second sit-to-stand test for the EG were poor at baseline and significantly better after 6 months, while the results for the CG worsened between baseline and 6 months. CONCLUSIONS / IMPLICATIONS FOR PRACTICE: The results of this study support that participating in a group-based OEP three times per week over 6 months effectively improves lower extremity muscle strength in older adults. Therefore, OEP should be incorporated into fall-prevention programs organized in long-term care institutions.


Assuntos
Terapia por Exercício , Extremidade Inferior/fisiologia , Força Muscular/fisiologia , Instituições Residenciais , Idoso de 80 Anos ou mais , Humanos , Assistência de Longa Duração , Avaliação de Programas e Projetos de Saúde , Taiwan
20.
PLoS One ; 15(6): e0233796, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497130

RESUMO

BACKGROUND: Rugby union match demands are complex, requiring the development of multiple physical qualities concurrently. Quantifying the physical qualities of age grade rugby union players is vital for practitioners to support athlete preparation and long-term development. AIM: This systematic review aimed to identify the methods used to quantify the physical qualities of male age grade (≤ Under-20) rugby union players, present the normative values for physical qualities, and compare physical qualities between age grades and positions. METHODS: Electronic databases were systematically reviewed from the earliest record to November 2019 using key words relating to sex, age, sport and physical testing. RESULTS: Forty-two studies evaluated the physical qualities of age grade rugby union players. Seventy-five tests were used to quantify body composition, muscular strength, muscular power, linear speed, change of direction ability, aerobic capacity and anaerobic endurance. Thirty-one studies met the eligibility criteria to present the physical qualities. Physical qualities differentiate between age groups below Under-16, while differences in older age groups (Under-16 to Under-20) are not clear. Positional differences are present with forwards possessing greater height, body mass, body fat percentage and strength while backs are faster and have greater aerobic capacities. CONCLUSIONS: A wide variety of tests are used to assess physical qualities limiting between study comparisons. Although differences in older age grades are unclear, older age groups (Under-19-20) generally performed better in physical tests. Positional differences are associated with match demands where forwards are exposed to less running but a greater number of collisions. Practitioners can use the results from this review to evaluate the physical qualities of age grade rugby union players to enhance training prescription, goal setting and player development. Future research should consider the use of national standardised testing batteries due to the inconsistency in testing methods and small samples limiting the reporting of positional differences.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Futebol Americano/fisiologia , Força Muscular/fisiologia , Adolescente , Composição Corporal/fisiologia , Tamanho Corporal/fisiologia , Criança , Humanos , Masculino , Resistência Física/fisiologia , Aptidão Física/fisiologia , Corrida/fisiologia , Adulto Jovem
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