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1.
J Funct Morphol Kinesiol ; 6(4)2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34698223

RESUMO

The mechanical properties of knee flexors and extensors in 15 collegiate male soccer players following different warm-up protocols [small-sided games (SSG), dynamic (DYN), and plyometric (PLY)] were evaluated. Tensiomyography (TMG) was used to assess contraction time (Tc), delay time (Td) and maximal displacement (Dm) of the rectus femoris (RF) and biceps femoris (BF) of both legs before and after each warm-up, while countermovement jump height variables, 20 m sprint, t-test and sit-and-reach were measured following the warm-ups. TMG was analyzed using a three-way [condition × time × leg] ANOVA, while performance variables were analyzed with a repeated measures ANOVA. Main effects of time were observed for BF-Tc (p = 0.035), RF-Td (p < 0.001), and BF-Td, (p = 0.008), and a main effect of condition was seen for RF-Tc (p = 0.038). Moreover, participants' 20 m sprint improved following SSG (p = 0.021) compared to DYN and PLY. Sit-and-reach was greater following PLY (p = 0.021). No significant interactions were noted for the measured TMG variables. Warm-up-specific improvements were demonstrated in sprint speed and flexibility following SSG and PLY, respectively. The present study revealed changes in certain TMG measures following the warm-ups that suggest enhanced response of lower leg muscles regardless of specific activities used.

2.
J Int Soc Sports Nutr ; 18(1): 61, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34503527

RESUMO

Based on a comprehensive review and critical analysis of the literature regarding the effects of sodium bicarbonate supplementation on exercise performance, conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society: 1. Supplementation with sodium bicarbonate (doses from 0.2 to 0.5 g/kg) improves performance in muscular endurance activities, various combat sports, including boxing, judo, karate, taekwondo, and wrestling, and in high-intensity cycling, running, swimming, and rowing. The ergogenic effects of sodium bicarbonate are mostly established for exercise tasks of high-intensity that last between 30 s and 12 min. 2. Sodium bicarbonate improves performance in single- and multiple-bout exercise. 3. Sodium bicarbonate improves exercise performance in both men and women. 4. For single-dose supplementation protocols, 0.2 g/kg of sodium bicarbonate seems to be the minimum dose required to experience improvements in exercise performance. The optimal dose of sodium bicarbonate dose for ergogenic effects seems to be 0.3 g/kg. Higher doses (e.g., 0.4 or 0.5 g/kg) may not be required in single-dose supplementation protocols, because they do not provide additional benefits (compared with 0.3 g/kg) and are associated with a higher incidence and severity of adverse side-effects. 5. For single-dose supplementation protocols, the recommended timing of sodium bicarbonate ingestion is between 60 and 180 min before exercise or competition. 6. Multiple-day protocols of sodium bicarbonate supplementation can be effective in improving exercise performance. The duration of these protocols is generally between 3 and 7 days before the exercise test, and a total sodium bicarbonate dose of 0.4 or 0.5 g/kg per day produces ergogenic effects. The total daily dose is commonly divided into smaller doses, ingested at multiple points throughout the day (e.g., 0.1 to 0.2 g/kg of sodium bicarbonate consumed at breakfast, lunch, and dinner). The benefit of multiple-day protocols is that they could help reduce the risk of sodium bicarbonate-induced side-effects on the day of competition. 7. Long-term use of sodium bicarbonate (e.g., before every exercise training session) may enhance training adaptations, such as increased time to fatigue and power output. 8. The most common side-effects of sodium bicarbonate supplementation are bloating, nausea, vomiting, and abdominal pain. The incidence and severity of side-effects vary between and within individuals, but it is generally low. Nonetheless, these side-effects following sodium bicarbonate supplementation may negatively impact exercise performance. Ingesting sodium bicarbonate (i) in smaller doses (e.g., 0.2 g/kg or 0.3 g/kg), (ii) around 180 min before exercise or adjusting the timing according to individual responses to side-effects, (iii) alongside a high-carbohydrate meal, and (iv) in enteric-coated capsules are possible strategies to minimize the likelihood and severity of these side-effects. 9. Combining sodium bicarbonate with creatine or beta-alanine may produce additive effects on exercise performance. It is unclear whether combining sodium bicarbonate with caffeine or nitrates produces additive benefits. 10. Sodium bicarbonate improves exercise performance primarily due to a range of its physiological effects. Still, a portion of the ergogenic effect of sodium bicarbonate seems to be placebo-driven.


Assuntos
Desempenho Atlético , Exercício Físico , Substâncias para Melhoria do Desempenho , Bicarbonato de Sódio , Ciências da Nutrição e do Esporte , Desempenho Atlético/fisiologia , Feminino , Humanos , Masculino , Substâncias para Melhoria do Desempenho/farmacologia , Bicarbonato de Sódio/farmacologia
3.
Nutrients ; 13(8)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34444681

RESUMO

Creatine (Cr) and phosphocreatine (PCr) are physiologically essential molecules for life, given they serve as rapid and localized support of energy- and mechanical-dependent processes. This evolutionary advantage is based on the action of creatine kinase (CK) isozymes that connect places of ATP synthesis with sites of ATP consumption (the CK/PCr system). Supplementation with creatine monohydrate (CrM) can enhance this system, resulting in well-known ergogenic effects and potential health or therapeutic benefits. In spite of our vast knowledge about these molecules, no integrative analysis of molecular mechanisms under a systems biology approach has been performed to date; thus, we aimed to perform for the first time a convergent functional genomics analysis to identify biological regulators mediating the effects of Cr supplementation in health and disease. A total of 35 differentially expressed genes were analyzed. We identified top-ranked pathways and biological processes mediating the effects of Cr supplementation. The impact of CrM on miRNAs merits more research. We also cautiously suggest two dose-response functional pathways (kinase- and ubiquitin-driven) for the regulation of the Cr uptake. Our functional enrichment analysis, the knowledge-based pathway reconstruction, and the identification of hub nodes provide meaningful information for future studies. This work contributes to a better understanding of the well-reported benefits of Cr in sports and its potential in health and disease conditions, although further clinical research is needed to validate the proposed mechanisms.


Assuntos
Creatina/administração & dosagem , Perfilação da Expressão Gênica , Genômica/métodos , Desempenho Físico Funcional , Animais , Creatina/metabolismo , Creatina Quinase/metabolismo , Suplementos Nutricionais , Metabolismo Energético , Estudo de Associação Genômica Ampla , Humanos , Camundongos , Proteínas Quinases Ativadas por Mitógeno , Proteínas de Transporte de Neurotransmissores , Fosfocreatina/metabolismo , Transdução de Sinais
4.
Nutrients ; 13(6)2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34071875

RESUMO

Numerous health conditions affecting the musculoskeletal, cardiopulmonary, and nervous systems can result in physical dysfunction, impaired performance, muscle weakness, and disuse-induced atrophy. Due to its well-documented anabolic potential, creatine monohydrate has been investigated as a supplemental agent to mitigate the loss of muscle mass and function in a variety of acute and chronic conditions. A review of the literature was conducted to assess the current state of knowledge regarding the effects of creatine supplementation on rehabilitation from immobilization and injury, neurodegenerative diseases, cardiopulmonary disease, and other muscular disorders. Several of the findings are encouraging, showcasing creatine's potential efficacy as a supplemental agent via preservation of muscle mass, strength, and physical function; however, the results are not consistent. For multiple diseases, only a few creatine studies with small sample sizes have been published, making it difficult to draw definitive conclusions. Rationale for discordant findings is further complicated by differences in disease pathologies, intervention protocols, creatine dosing and duration, and patient population. While creatine supplementation demonstrates promise as a therapeutic aid, more research is needed to fill gaps in knowledge within medical rehabilitation.


Assuntos
Creatina , Suplementos Nutricionais , Reabilitação , Adolescente , Adulto , Criança , Creatina/farmacologia , Creatina/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiologia , Doenças Musculares/tratamento farmacológico , Doenças Musculares/fisiopatologia , Doenças Musculares/reabilitação , Adulto Jovem
5.
J Strength Cond Res ; 35(6): 1535-1541, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34027920

RESUMO

ABSTRACT: Herda, AA, Smith-Ryan, AE, Kendall, KL, Cramer, JT, and Stout, JR. Evaluation of high-intensity interval training and beta-alanine supplementation on efficiency of electrical activity and electromyographic fatigue threshold. J Strength Cond Res 35(6): 1535-1541, 2021-The purpose of this study was to determine the effects of high-intensity interval training (HIIT) with or without ß-alanine (BA) supplementation on the electromyographic fatigue threshold (EMGFT) and efficiency of electrical activity (EEA) in young women. Forty-four women (mean ± SD; age [yrs]: 21.7 ± 3.7; height [cm]: 166.3 ± 6.4; body mass [kg]: 66.1 ± 10.3) were randomly assigned to one of 3 treatment groups. The supplement groups performed HIIT on the cycle ergometer 3 times·wk-1 for 6 weeks. Electromyographic fatigue threshold and EEA were assessed at baseline (PRE), after 3 weeks of training (MID), and after 6 weeks of HIIT (POST). Two 2-way mixed factorial analyses of variance (time [PRE vs. MID vs. POST] × treatment (BA vs. PL vs. CON)] were used to analyze EMGFT and EEA with a predetermined level of significance α of 0.05. For EMGFT, there was no interaction (p = 0.26) and no main effect for time (p = 0.28) nor treatment (p = 0.86); thus, there were no changes in EMGFT regardless of training or supplementation status. For EEA, there was no interaction (p = 0.70) nor treatment (p = 0.79); however, there was a main effect for time (p < 0.01). Our findings indicated that neither training nor supplementation was effective in improving EMGFT in women. Efficiency of electrical activity was altered, potentially because of a learning effect. Coaches and practitioners may not use these tests to monitor training status; however, they may find EEA as a useful tool to track cycling efficiency.


Assuntos
Treinamento Intervalado de Alta Intensidade , Suplementos Nutricionais , Eletromiografia , Teste de Esforço , Fadiga , Feminino , Humanos , Fadiga Muscular , Consumo de Oxigênio , beta-Alanina
6.
JMIR Res Protoc ; 10(4): e27381, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33825688

RESUMO

BACKGROUND: One-third of older adults have maladaptive fall risk appraisal (FRA), a condition in which there is a discrepancy between the level of fear of falling (FOF) and physiological fall risk (balance performance). Older adults who overestimate their physiological fall risk and report a high FOF are less likely to participate in physical activity. Limited data suggest that the association among FOF, body composition, and physical activity intensity differs by fear severity. OBJECTIVE: This study aims to examine the associations among FRA, body composition, and physical activity using assistive health technology, including the BTrackS balance system, bioelectrical impedance analysis, and activity monitoring devices. This study also aims to examine the feasibility of recruitment and acceptability of technologies and procedures for use among older adults in low-income settings. METHODS: This cross-sectional study will be conducted in older adults' homes or apartments in low-income settings in Central Florida, United States. Following consent, participants will be contacted, and our team will visit them twice. The first visit includes questionnaire completion (eg, sociodemographic or FOF) and balance performance test using the BTrackS balance system. The participants will be stratified by the FRA matrix. In addition, they will perform hand grip strength and dynamic balance performance tests. Participants will then be asked to wear the ActiGraph GT9X Link wireless activity monitor on the nondominant wrist for 7 consecutive days. The second visit includes body composition testing and a structured interview about the acceptability of the technologies and procedures. RESULTS: Ethical approval was obtained from the institutional review board of the University of Central Florida (protocol number 2189; September 10, 2020). As of December 2020, participation enrollment is ongoing and the results are expected to be published in Summer 2022. CONCLUSIONS: Accurate FRA is essential for implementing physical activity programs, especially in older adults with low income. This study will provide data for developing technology-based fall risk assessments to improve participation in physical activity, thus enhancing healthy longevity among older adults in low-income settings. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/27381.

7.
Nutrients ; 13(4)2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33918657

RESUMO

Creatine (Cr) is a ubiquitous molecule that is synthesized mainly in the liver, kidneys, and pancreas. Most of the Cr pool is found in tissues with high-energy demands. Cr enters target cells through a specific symporter called Na+/Cl--dependent Cr transporter (CRT). Once within cells, creatine kinase (CK) catalyzes the reversible transphosphorylation reaction between [Mg2+:ATP4-]2- and Cr to produce phosphocreatine (PCr) and [Mg2+:ADP3-]-. We aimed to perform a comprehensive and bioinformatics-assisted review of the most recent research findings regarding Cr metabolism. Specifically, several public databases, repositories, and bioinformatics tools were utilized for this endeavor. Topics of biological complexity ranging from structural biology to cellular dynamics were addressed herein. In this sense, we sought to address certain pre-specified questions including: (i) What happens when creatine is transported into cells? (ii) How is the CK/PCr system involved in cellular bioenergetics? (iii) How is the CK/PCr system compartmentalized throughout the cell? (iv) What is the role of creatine amongst different tissues? and (v) What is the basis of creatine transport? Under the cellular allostasis paradigm, the CK/PCr system is physiologically essential for life (cell survival, growth, proliferation, differentiation, and migration/motility) by providing an evolutionary advantage for rapid, local, and temporal support of energy- and mechanical-dependent processes. Thus, we suggest the CK/PCr system acts as a dynamic biosensor based on chemo-mechanical energy transduction, which might explain why dysregulation in Cr metabolism contributes to a wide range of diseases besides the mitigating effect that Cr supplementation may have in some of these disease states.


Assuntos
Biologia Computacional , Creatina/metabolismo , Doença , Saúde , Animais , Transporte Biológico , Creatina/biossíntese , Creatina/química , Creatina Quinase/metabolismo , Humanos
8.
J Int Soc Sports Nutr ; 18(1): 1, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33388079

RESUMO

Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows: 1. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions. 2. Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals. 3. Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3-6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect. 4. The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session. 5. Caffeine appears to improve physical performance in both trained and untrained individuals. 6. Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation. 7. Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals. 8. Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation. 9. The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4-6 mg/kg, respectively. 10. Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise. 11. Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.


Assuntos
Cafeína/farmacologia , Exercício Físico/fisiologia , Sociedades Médicas , Fenômenos Fisiológicos da Nutrição Esportiva , Ciências da Nutrição e do Esporte , Ansiedade/induzido quimicamente , Ansiedade/genética , Desempenho Atlético/fisiologia , Cafeína/administração & dosagem , Cafeína/efeitos adversos , Cafeína/farmacocinética , Cápsulas , Goma de Mascar , Cognição/efeitos dos fármacos , Citocromo P-450 CYP1A2/genética , Citocromo P-450 CYP1A2/metabolismo , Doping nos Esportes , Cálculos da Dosagem de Medicamento , Bebidas Energéticas , Temperatura Alta , Humanos , Movimento/efeitos dos fármacos , Movimento/fisiologia , Força Muscular/efeitos dos fármacos , Força Muscular/fisiologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiologia , Substâncias para Melhoria do Desempenho/farmacologia , Resistência Física/efeitos dos fármacos , Resistência Física/fisiologia , Desempenho Físico Funcional , Receptor A2A de Adenosina/genética , Receptor A2A de Adenosina/metabolismo , Sono/efeitos dos fármacos
9.
Curr Opin Clin Nutr Metab Care ; 24(1): 48-52, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33148945

RESUMO

PURPOSE OF REVIEW: The interest in the use of beta-hydroxy-beta-methylbutyrate (HMB) as an intervention to prevent and treat sarcopenia has increased over recent years. The purpose of this review is to explore recent evidence pertaining to the mechanism of action of HMB and how this may influence changes in lean mass and strength in older persons who are both hospitalized and living in the community. RECENT FINDINGS: No new studies have been published over the last 2 years investigating the effect of HMB in older persons who are hospitalized, aside from one posthoc analysis of a randomized controlled trial exploring the effect of a high protein oral nutrition supplement containing HMB on handgrip strength and nutritional status. Three studies recruiting community-dwelling older adults have been published, but results are influenced by suboptimal methodological quality. SUMMARY: Recent data suggest the need for high-quality studies investigating the effectiveness of HMB to improve outcomes related to sarcopenia in both hospitalized and community-dwelling older persons.


Assuntos
Força da Mão , Sarcopenia , Idoso , Idoso de 80 Anos ou mais , Suplementos Nutricionais , Humanos , Músculo Esquelético , Ensaios Clínicos Controlados Aleatórios como Assunto , Sarcopenia/tratamento farmacológico , Sarcopenia/prevenção & controle , Valeratos
10.
Nutrients ; 12(8)2020 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-32784372

RESUMO

This study examined the cardiac autonomic responses, as measured by heart rate variability (HRV), during cycling exercise and short-term rest after energy drink consumption. Seventeen participants (seven males and 10 females; age: 22.8 ± 3.5 years; BMI: 24.3 ± 3.3 kg/m2) completed this double-blind, placebo-controlled, counterbalanced crossover design study. Participants received an energy drink formula containing 140 mg of caffeine and a placebo in a randomized order before completing a 10-min steady-state warm up (WUP) and a graded exercise test to exhaustion (GXT) followed by a 15-min short-term rest (STR) period. Heartbeat intervals were recorded using a heart rate monitor. Data were divided into WUP, GXT, and STR phases, and HRV parameters were averaged within each phase. Additionally, root mean square of the standard deviation of R-R intervals (RMSSD) during GXT was analyzed to determine the HRV threshold. Separate two-way (sex (male vs. female) x drink (energy drink vs. placebo)) repeated measures ANOVA were utilized. Significant increases in high frequency (HF) and RMSSD were shown during WUP after energy drink consumption, while interactions between drink and sex were observed for HRV threshold parameters (initial RMSSD and rate of RMSSD decline). No significant differences were noted during STR. Energy drink consumption may influence cardiac autonomic responses during low-intensity exercise, and sex-based differences in response to graded exercise to exhaustion may exist.


Assuntos
Ciclismo/fisiologia , Ingestão de Líquidos/fisiologia , Bebidas Energéticas , Frequência Cardíaca/fisiologia , Fatores Sexuais , Análise de Variância , Cafeína/administração & dosagem , Estudos Cross-Over , Método Duplo-Cego , Metabolismo Energético/fisiologia , Teste de Esforço , Feminino , Humanos , Masculino , Esforço Físico/fisiologia , Descanso/fisiologia , Adulto Jovem
11.
J Aging Phys Act ; 29(1): 17-26, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32604068

RESUMO

The purpose of this trial was to examine the effects of self-selected exercise intensities plus either whey protein or placebo supplementation on vital signs, body composition, bone mineral density, muscle strength, and mobility in older adults. A total of 101 participants aged 55 years and older (males [n = 34] and females [n = 67]) were evaluated before and after 12 weeks of self-selected, free-weight resistance exercise plus 30 min of self-paced walking three times per week. The participants were randomized into two groups: whey protein (n = 46) or placebo (n = 55). Three-way mixed factorial analyses of variance were used to test for mean differences for each variable. The 12 weeks of self-selected, self-paced exercise intensities improved resting heart rate, fat-free mass, percent body fat, handgrip strength, bench press strength, leg press strength, and all mobility measurements (p < .05) in males and females despite supplementation status. This suggests that additional protein in well-fed healthy older adults does not enhance the benefit of exercise.


Assuntos
Composição Corporal , Exercício Físico/fisiologia , Força da Mão , Músculo Esquelético/metabolismo , Treinamento de Força , Proteínas do Soro do Leite/administração & dosagem , Idoso , Suplementos Nutricionais , Método Duplo-Cego , Feminino , Humanos , Masculino , Força Muscular , Aptidão Física
12.
Physiol Rep ; 8(9): e14426, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32378353

RESUMO

The purpose of this study was to assess the maturity-related differences in the aerobic and anaerobic adaptations to sprint interval training (SIT) among youth male athletes. Twenty-seven youth male athletes were assessed for years from peak height velocity (PHV) and classified into prepubescent (PRE, n = 7, years from PHV = -2.21 ± 0.47 years), peripubescent (PERI, n = 10, years from PHV = 0.25 ± 0.88 years), and postpubescent (POST, n = 10, years from PHV = 2.81 ± 0.50 years) groups based on their years from estimated peak height velocity. Participants completed a ramp exercise protocol on a cycle ergometer to determine maximal aerobic power, maximal oxygen consumption (VO2peak ), and fatigue thresholds. Following baseline, all participants completed a 4-week SIT program that consisted of eight total training sessions. During each session, participants completed repeated 20-s sprints on a cycle ergometer against a resistance of 7.5% of body mass. The number of sprints per sessions increased from four in session 1 to seven in session 7, with four sprints in session 8. Peak and mean power from sessions 1 and 8 were recorded. All participants completed a post-testing ramp exercise protocol that mirrored baseline. Maximal aerobic power increased (p < .001) across all groups from baseline (212.61 ± 57.45 W) to post-testing (223.24 ± 58.90 W); however, VO2peak only increased in POST (3.31 ± 0.43 to 3.54 ± 0.43 L min-1 , p = .003). Similarly, GET, VT, and RCP increased in POST, with no changes in PRE or PERI. In terms of anaerobic performance, PERI and POST had significant increases in peak and mean power. POST improved aerobic and anaerobic performance following SIT, while PERI only experienced improvements in anaerobic performance. Conversely, PRE had no changes in aerobic or anaerobic performance. The adaptations to SIT appear to be influenced by the somatic maturity status.


Assuntos
Adaptação Fisiológica/fisiologia , Atletas , Desempenho Atlético/fisiologia , Exercício Físico/fisiologia , Treinamento Intervalado de Alta Intensidade/métodos , Adolescente , Anaerobiose , Criança , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Puberdade/fisiologia , Corrida/fisiologia
13.
Res Gerontol Nurs ; 13(6): 289-296, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32286669

RESUMO

A one-group pre/posttest study was conducted to examine the feasibility and effect size of an 8-week physio-feedback and exercise program (PEER) on improving balance, muscle strength, and fall risk. Nineteen participants (mean age = 76 years) received the intervention, which included visual physio-feedback by the BTrackS™ Assess Balance System, cognitive reframing, and a combined group- and home-based exercise program by a trained peer coach. Pre- and post-measurement outcomes were evaluated for balance, handgrip strength, and fall risk. Feasibility was assessed by dropout rate, safety, and adherence to exercise. Significant improvements were noted in dynamic balance (Sit-to-Stand, Timed Up & Go tests), handgrip strength, and fall risk. Participants' attendance was 87.5%, with no fall incidence. The physio-feedback, cognitive reframing, and peer coaching facilitate older adults to align their perceived fall risk with physiological fall risk and motivate them to stay active. PEER intervention is feasible; safe; improves balance, muscle strength, and fall risk; and may enhance activity engagement. TARGETS: Community-dwelling older adults. INTERVENTION DESCRIPTION: Provide visual physio-feedback and cognitive reframing based on the fall risk appraisal matrix and participate in combined group- and home-based exercises by a trained peer coach. MECHANISM OF ACTION: Align perceived and physiological fall risk, peer coaching to exercise. OUTCOMES: Balance, handgrip strength, fall risk, and activity engagement. [Research in Gerontological Nursing, 13(6), 289-296.].


Assuntos
Acidentes por Quedas/prevenção & controle , Exercício Físico/fisiologia , Retroalimentação , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Idoso , Feminino , Promoção da Saúde , Humanos , Vida Independente , Masculino
14.
J Sports Sci ; 38(14): 1615-1623, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32316854

RESUMO

Post-activation potentiation likely acutely improves power-based performance; however, few studies have demonstrated improved endurance performance. Forty collegiate female rowers performed isometric potentiating (ISO), dynamic potentiating (DYN) and control (CON) warm-up protocols on a rowing ergometer, followed by a three-minute all-out test to evaluate their total distance, peak power, mean power, critical power, anaerobic working capacity (W') and stroke rate. Fifteen-second splits were also analysed. ISO consisted of 5 × 5-second static muscle actions with the ergometer handle rendered immovable with a nylon strap, while DYN consisted of 2 × 10-second all-out rowing bouts, separated by a 2-minute rest interval. The participants were divided into high and low experience groups by median experience level (3.75 years) for statistical analysis. Significant differences (DYN > CON; p < 0.05) were found for distance (+5.6 m), mean power (+5.9 W) and W' (+1561.6 J) for more experienced rowers (n = 19) and no differences for less experienced rowers (n = 18). Mean power in DYN was significantly greater than CON and ISO in the 15-30, 30-45, 45-60 and 60-75 second intervals independent of experience level. These results suggest that DYN may benefit experienced female rowers and that these strategies might benefit a greater power output over shorter distances regardless of experience.


Assuntos
Resistência Física/fisiologia , Exercício de Aquecimento , Esportes Aquáticos/fisiologia , Estudos Cross-Over , Teste de Esforço , Feminino , Humanos , Contração Isométrica/fisiologia , Adulto Jovem
15.
J Gerontol Nurs ; 46(4): 41-47, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32219456

RESUMO

The current study aimed to categorize fall risk appraisal and quantify discrepancies between perceived fall risk measured subjectively using the short Fall Efficacy Scale-International and physiological fall risk measured objectively using the portable BTrackS™ Assess Balance System. One hundred two community-dwelling older adults were evaluated in this cross-sectional study. Approximately 40% of participants had maladaptive fall risk appraisals, which were either irrational (high perceived risk despite low physiological fall risk) or incongruent (low perceived risk but high physiological fall risk). The remaining 60% of participants had adaptive fall risk appraisals, which were either rational (low perceived risk aligned with low physiological fall risk) or congruent (high perceived risk aligned with high physiological fall risk). Among participants with rational, congruent, irrational, and incongruent appraisals, 21.7%, 66.7%, 28%, and 18.8%, respectively, reported having a history of falls (p < 0.01). Using technology to identify discrepancies in perceived and physiological fall risks can potentially increase the success of fall risk screening and guide fall interventions to target perceived or physiological components of balance. [Journal of Gerontological Nursing, 46(4), 41-47.].


Assuntos
Acidentes por Quedas/prevenção & controle , Avaliação Geriátrica/métodos , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Vida Independente , Masculino , Equilíbrio Postural , Medição de Risco , Fatores de Risco , Tecnologia
16.
J Int Soc Sports Nutr ; 17(1): 10, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32054486

RESUMO

BACKGROUND: Thermogenic fitness drink formulas (TFD) have been shown to increase energy expenditure and markers of lipid metabolism. The purpose of the current study was to compare TFD formulas containing different caffeine concentrations versus a placebo drink on energy expenditure and lipid metabolism at rest and during exercise. METHODS: Thirty-two recreationally active participants (22.9 ± 0.7 y, 167.1 ± 1.4 cm, 68.8 ± 2.0 kg, 24.0 ± 1.2% fat) who were regular caffeine consumers, participated in this randomized, double-blind, crossover design study. Participants reported to the laboratory on three occasions, each of which required consumption of either a TFD containing 140 mg or 100 mg of caffeine or a placebo. Baseline measurements of resting energy expenditure (REE) and resting fat oxidation (RFO) were assessed using indirect calorimetry as well as measurements of serum glycerol concentration. Measurements were repeated at 30, 60, 90 min post-ingestion. Following resting measures, participants completed a graded exercise test to determine maximal oxygen uptake (V̇O2max), maximal fat oxidation (MFO) and the exercise intensity that elicits MFO (Fatmax), and total energy expenditure (EE). RESULTS: A significant interaction was shown for REE (p < 0.01) and RFO (p < 0.01). Area under the curve analysis showed an increased REE for the 140 mg compared to the 100 mg formula (p = 0.02) and placebo (p < 0.01) and an increased REE for the 100 mg formula compared to placebo (p = 0.02). RFO significantly decreased for caffeinated formulas at 30 min post ingestion compared to placebo and baseline (p < 0.01) and significantly increased for the 140 mg formula at 60 min post-ingestion (p = 0.03). A main effect was shown for serum glycerol concentrations over time (p < 0.01). No significant differences were shown for V̇O2max (p = 0.12), Fatmax (p = 0.22), and MFO (p = 0.05), and EE (p = 0.08) across drinks. CONCLUSIONS: Our results suggest that TFD formulas containing 100 and 140 mg of caffeine are effective in increasing REE and that a 40 mg of caffeine difference between the tested formulas may impact REE and RFO in healthy individuals within 60 min of ingestion.


Assuntos
Cafeína/farmacologia , Metabolismo Energético , Exercício Físico , Metabolismo dos Lipídeos , Substâncias para Melhoria do Desempenho/farmacologia , Adolescente , Adulto , Bebidas , Calorimetria Indireta , Estudos Cross-Over , Método Duplo-Cego , Teste de Esforço , Feminino , Glicerol/sangue , Humanos , Masculino , Descanso , Adulto Jovem
17.
High Alt Med Biol ; 21(1): 62-69, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31928420

RESUMO

Background: Sex-based differences in metabolism and morphological characteristics may result in unique exercise responses during periods of limited oxygen availability. Purpose: To evaluate the effects of moderate normobaric hypoxia on the parameters of the work-time relationship during upper body exercise in women. Materials and Methods: Thirteen recreationally active women (age: 22.7 ± 2.6 years; height: 167 ± 8.6 cm; weight: 66.4 ± 9.7 kg; body fat: 27.6% ± 5% body fat) completed a maximal graded exercise test in both normobaric hypoxia (H; fraction of inspired oxygen (FiO2) = 0.14) and normoxia (N; FiO2 = 0.20) on an arm ergometer to determine peak oxygen uptake (VO2peak) and peak power output (PPO). Each participant completed four constant, work rate, arm-cranking time-to-exhaustion tests at 90%-120% PPO in both environmental conditions. Linear regression was used to estimate critical power (CP) and anaerobic capacity (W') through the work-time relationship during the constant work rate tests. Paired sample t-tests compared mean differences between VO2peak, PPO, CP, and W' between conditions (normoxia vs. hypoxia). Two-way (condition × intensity) repeated measures analysis of variance (ANOVA) was used to compare total work (TW) and time to exhaustion. Results: Hypoxia significantly reduced VO2peak (N: 1.73 ± 0.31 L·minute-1 vs. H: 1.62 ± 0.27 L·minute-1, p = 0.008), but had no effects on PPO (N: 78.08 ± 14.51 W vs. H: 75.38 ± 13.46 W, p = 0.09), CP (N: 57.44 ± 18.89 W vs. H: 56.01 ± 12.36 W, p = 0.55), and W' (N: 4.81 ± 1.01 kJ vs. H: 4.56 ± 0.91 kJ, p = 0.51). No significant condition × intensity interactions were noted for TW or time to exhaustion (p > 0.05). Conclusions: Moderate normobaric hypoxia significantly reduced VO2peak, but had minimal effects on CP and W' using the work-time model in women.


Assuntos
Teste de Esforço , Consumo de Oxigênio , Adulto , Exercício Físico , Tolerância ao Exercício , Feminino , Humanos , Hipóxia , Resistência Física , Adulto Jovem
18.
Sports Biomech ; 19(4): 438-451, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30136909

RESUMO

The majority of barefoot running studies have not considered speed as an influential factor on foot strike pattern. The aim of this study was to investigate differences in foot strike pattern and spatiotemporal characteristics between barefoot and shod overground running at varying speeds. We first determined maximal running speed (Vm) over 50 m in 15 recreationally active men who self-reported as habitual rearfoot strikers. Participants then completed shod and barefoot running trials at different speeds equivalent to approximately 90%, 80%, 70% and 60% of Vm. Sagittal plane two-dimensional (2D) foot-ground contact angle, ankle plantar-dorsi flexion angle, contact time, flight time, step length and step rate variables for each trial were recorded. A significant interaction effect of running speed and footwear condition (p < 0.05) on foot-ground contact angle, ankle plantar-dorsi flexion angle and contact time was observed. There was a main effect of running speed (p < 0.01) on flight time, step length and step rate. There was a main effect of footwear condition on step length (p < 0.01). Participants were more inclined to plantarflex the ankle and contact the ground with the forefoot at higher percentages of Vm, especially when running barefoot.


Assuntos
Pé/fisiologia , Corrida/fisiologia , Sapatos , Aceleração , Tornozelo/fisiologia , Fenômenos Biomecânicos , Desenho de Equipamento , Análise da Marcha , Humanos , Masculino , Estudos de Tempo e Movimento , Adulto Jovem
19.
Clin Gerontol ; 43(4): 378-390, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31713464

RESUMO

OBJECTIVES: 1) examine the preliminary effectiveness of the Physio-feEdback and Exercise pRogram (PEER) for shifting maladaptive to adaptive fall risk appraisal and reducing fall risk, 2) determine the participants' feedback and acceptability of the program. METHODS: Forty-one older adults were assigned to either PEER intervention or attention control group. The 8-week PEER intervention consists of a visual physio-feedback, cognitive reframing, and combined group and home-based exercise led by a trained peer coach. The attention control group read fall prevention brochures and continued their normal activities. BTrackS Balance Test (BBT), short version of Fall Efficacy Scale International (short FES-I) and CDC fall risk checklist were measured from pre- to post-intervention. The feedback and acceptability were conducted at the program conclusion. RESULTS: About 11% of participants in the PEER group had positive shifting but none in the attention control group. Up to 32% of the participants in attention control had negative shifting compared to 5.3% in the PEER group. PEER group reported significant decreases in fall risk and high acceptability of the program. CONCLUSIONS: PEER intervention facilitates a shift from maladaptive to adaptive fall risk appraisal and reduces fall risk. CLINICAL IMPLICATIONS: Preventive interventions promoting alignment between perceive and physiological fall risk may contribute to reducing falls and increasing exercise adherence.


Assuntos
Acidentes por Quedas , Terapia por Exercício , Acidentes por Quedas/prevenção & controle , Idoso , Retroalimentação , Humanos , Grupo Associado , Projetos Piloto
20.
J Autism Dev Disord ; 50(4): 1418-1424, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31848796

RESUMO

To examine the preliminary efficacy of an 8-week judo program to promote moderate-to-vigorous physical activity (MVPA) and reduce sedentary behavior (SB) in youth with Autism Spectrum Disorder (ASD). Fourteen children diagnosed with ASD participated in a weekly judo program over a period of 8 weeks. Participants wore an Actigraph accelerometer to measure activity levels at baseline and post-judo. All 14 children attended at least 75% of the 8 judo classes. Percentage of time spent in daily MVPA (8% vs 4%, p = .05) increased following the intervention. A high rate of participation and an increase in time spent in MVPA was observed following the 8-week program. Further research to examine causal mechanisms is warranted.


Assuntos
Transtorno do Espectro Autista/reabilitação , Terapia por Exercício/métodos , Promoção da Saúde/métodos , Artes Marciais , Adolescente , Criança , Exercício Físico , Feminino , Humanos , Masculino
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