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1.
Life Sci ; 240: 117107, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31785241

RESUMO

BACKGROUND: Toll-like receptor 4 (Tlr4) is recognized due to its role in the immune response. Also, this protein can participate in the signaling pathway of events triggered by physical exercise such as apoptosis, inflammation, and endoplasmic reticulum (ER) stress. The main objective of this study was to evaluate the role of Tlr4 in the markers of these events in the myocardium of mice submitted to acute physical exercise (APE) protocols at different intensities. METHODS: Echocardiogram, RT-qPCR, and immunoblotting technique were used to evaluate the left ventricle of wild-type (WT) and Tlr4 knockout (Tlr4 KO) submitted to APE protocols at 45, 60, and 75% of their maximal velocity. Also, we performed the bioinformatics analysis to establish the connection of heart mRNA levels of Tlr4 with heart genes of inflammation and ER stress of several isogenic strains of BXD mice. RESULTS: Under basal conditions, the Tlr4 deletion diminished the performance, and expression of inflammation and ER stress genes in the left ventricle, but increased the serum levels of CK, Il-17, and Tnf-alpha. Under the same exercise conditions, the Tlr4 deletion reduced the glycemia, serum levels of CK, Il-17, and Tnf-alpha, as well as genes and/or proteins related to apoptosis, inflammation and ER stress in the left ventricle, but increased the levels of CK-mb and LDH, as well as other genes related to apoptosis, inflammation, and ER stress in the left ventricle. CONCLUSION: Altogether, the current findings highlighted the effects of different acute exercise intensities were attenuated in the heart of Tlr4 KO mice.


Assuntos
Apoptose/fisiologia , Estresse do Retículo Endoplasmático/fisiologia , Coração/fisiologia , Inflamação , Esforço Físico/fisiologia , Receptor 4 Toll-Like/fisiologia , Animais , Apoptose/genética , Biologia Computacional , Creatina Quinase/sangue , Ecocardiografia , Estresse do Retículo Endoplasmático/genética , Coração/diagnóstico por imagem , Interleucina-17/sangue , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Esforço Físico/genética , Transdução de Sinais/fisiologia , Receptor 4 Toll-Like/genética , Fator de Necrose Tumoral alfa/sangue
2.
Int J Sports Med ; 41(1): 36-43, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31747699

RESUMO

Subconcussive head impacts (SHI), defined as impacts to the cranium that do not result in concussion symptoms, are gaining traction as a major public health concern. The contribution of physiological factors such as physical exertion and muscle damage to SHI-dependent changes in neurological measures remains unknown. A prospective longitudinal study examined the association between physiological factors and SHI kinematics in 15 high school American football players over one season. Players wore a sensor-installed mouthguard for all practices and games, recording frequency and magnitude of all head impacts. Serum samples were collected at 12 time points (pre-season, pre- and post-game for five in-season games, and post-season) and were assessed for an isoenzyme of creatine kinase (CK-MM) primarily found in skeletal muscle. Physical exertion was estimated in the form of excess post-exercise oxygen consumption (EPOC) from heart rate data captured during the five games. Mixed-effect regression models indicated that head impact kinematics were significantly and positively associated with change in CK-MM but not EPOC. There was a significant and positive association between CK-MM and EPOC. These data suggest that when examining SHI, effects of skeletal muscle damage should be considered when using outcome measures that may have an interaction with muscle damage.


Assuntos
Futebol Americano/lesões , Cabeça/fisiopatologia , Músculo Esquelético/lesões , Esforço Físico/fisiologia , Adolescente , Fenômenos Biomecânicos , Concussão Encefálica/fisiopatologia , Creatina Quinase Forma MM/sangue , Futebol Americano/fisiologia , Humanos , Estudos Longitudinais , Masculino , Músculo Esquelético/enzimologia , Consumo de Oxigênio/fisiologia , Estudos Prospectivos , Estados Unidos
3.
Int J Sports Med ; 41(1): 12-20, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31747702

RESUMO

In view of the growing amount of (intense) training in competitive sports, quick recovery plays a superior role in performance restoration. The aim of the present study was to compare the effects of active versus passive recovery during high-intensity interval training (HIIT) and sprint interval training (SIT) protocols on acute alterations of circulating blood cells. Twelve male triathletes/cyclists performed 1) a HIIT consisting of 4×4 min intervals, 2) a SIT consisting of 4×30s intervals, separated by either active or passive recovery. Blood samples were collected immediately before and at 0', 30', 60' and 180' (minutes) post-exercise. Outcomes comprised leukocytes, lymphocytes, neutrophils, mixed cell count, platelets, cellular inflammation markers (neutrophil/lymphocyte-ratio (NLR), platelet/lymphocyte-ratio (PLR)), and the systemic immune-inflammation index (SII). In view of HIIT, passive recovery attenuated the changes in lymphocytes and neutrophils compared to active recovery. In view of SIT, active recovery attenuated the increase in leukocytes, lymphocytes and absolute mixed cell count compared to passive recovery. Both protocols, independent of recovery, significantly increased NLR, PLR and SII up to 3h of recovery compared to pre-exercise values. The mode of recovery influences short-term alterations in the circulating fraction of leukocytes, lymphocytes, neutrophils and the mixed cell count, which might be associated with different hormonal and metabolic stress responses due to the mode of recovery.


Assuntos
Contagem de Células Sanguíneas , Treinamento Intervalado de Alta Intensidade/métodos , Homeostase/fisiologia , Inflamação/sangue , Esforço Físico/fisiologia , Adulto , Biomarcadores/sangue , Contagem de Eritrócitos , Humanos , Contagem de Leucócitos , Contagem de Linfócitos , Masculino , Neutrófilos/metabolismo , Contagem de Plaquetas , Adulto Jovem
4.
J Sports Sci ; 38(2): 121-129, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31661663

RESUMO

A common barrier to exercise is "lack of time". Accordingly, interest in low-volume, high-intensity training has grown exponentially since this activity is considered time-efficient. However, the high-intensity nature of this exercise may frequently result in feelings of displeasure creating another barrier for many people. The purpose of this study was to compare affective (pleasure-displeasure) responses to three low-volume, high-intensity exercise conditions, including a novel shortened-sprint protocol. Using a within-subjects, randomised crossover experiment, healthy participants (N = 36) undertook a single bout of: 1) traditional reduced-exertion, high-intensity interval training (TREHIT), 2) a novel, shortened-sprint REHIT (SSREHIT) protocol, and 3) sprint continuous training (SCT). Affect and perceived efforts were recorded throughout exercise using the Feeling Scale (FS) and the 15-point Borg Rating of Perceived Exertion (RPE) scale, respectively. Enjoyment was recorded 5 min post-exercise using the Exercise Enjoyment Scale (EES). Differences were found for FS (condition by time interaction: P = 0.01GG, η2 = 0.26), RPE (P = 0.01GG, η2 = 0.23), and enjoyment (P < 0.01) with all outcomes favouring SSREHIT. Shortened-sprint protocols may diminish feelings of displeasure and might be a time-efficient yet tolerable exercise choice to help motivate some people to increase their physical activity and fitness.


Assuntos
Treinamento Intervalado de Alta Intensidade/métodos , Treinamento Intervalado de Alta Intensidade/psicologia , Prazer , Adulto , Estudos Cross-Over , Feminino , Humanos , Masculino , Motivação , Percepção/fisiologia , Esforço Físico/fisiologia , Adulto Jovem
5.
J Sports Sci ; 38(2): 140-149, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31680636

RESUMO

The aim of this study was to assess the influence of a half-time (HT) re-warm up (RWU) strategy on measures of performance and the physical and perceptual response to soccer-specific activity. Ten male soccer players completed a control (CON) and RWU trial, in which participants completed 60 min (4 x 15-min periods with a 15-min HT interspersing the third and fourth periods) of a soccer-specific exercise protocol. The CON trial comprised a passive 15-min HT, whilst the RWU trial comprised a passive 12-min period, followed by a 3-min RWU. The RWU elicited an improvement in 20 m sprint times (d= 0.6; CON: 3.42 ± 0.20 s; RWU: 3.32 ± 0.12 s), and both squat (d= 0.6; CON: 26.96 ± 5.00 cm; RWU: 30.17 ± 5.13 cm) and countermovement jump height (d= 0.7; CON: 28.15 ± 4.72 cm; RWU: 31.53 ± 5.43 cm) following the RWU and during the initial stages of the second half. No significant changes were identified for 5 m or 10 m sprint performance, perceived muscle soreness, or PlayerLoadTM. Ratings of perceived exertion were however higher (~2 a.u) following the RWU. These data support the use of a HT RWU intervention to elicit acute changes in performance.


Assuntos
Desempenho Atlético/fisiologia , Desempenho Atlético/psicologia , Futebol/fisiologia , Exercício de Aquecimento/fisiologia , Adulto , Estudos Cross-Over , Frequência Cardíaca/fisiologia , Humanos , Masculino , Mialgia/psicologia , Percepção/fisiologia , Esforço Físico/fisiologia , Projetos Piloto , Exercício Pliométrico/psicologia , Adulto Jovem
6.
J Sports Sci ; 38(1): 1-5, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31575324

RESUMO

Previous research has shown enhanced performance and altered pacing behaviour in the presence of a virtual opponent during middle-distance cycling time trials with a duration of 2 min and longer. The purpose of this study was to determine whether these effects are also present in cycling time trials of shorter duration. Twelve physically active men completed three 1-km time trials. After a familiarisation trial (FAM), participants performed two experimental conditions: one without opponent (NO) and one with a virtual opponent (OP). Repeated-measures ANOVAs were used to assess differences in pacing and performance using power output and duration (p<0.05). No differences in mean finishing times (FAM: 91.5 ± 7.7 s; NO: 91.6 ± 6.4 s; OP: 90.9 ± 4.9 s; p=0.907) or power output (FAM: 382 ± 111 W; NO: 363 ± 80 W; OP: 367 ± 67; p=0.564) were found between experimental conditions. Furthermore, no differences in pacing profiles between experimental conditions were found (p=0.199). Similarly, rate of perceived exertion did not differ between experimental conditions at any moment (p=0.831). In conclusion, unlike events of a more prolonged duration (>2 min), the presence of an opponent did not affect participants' pacing behaviour in short duration 1-km time trials.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Comportamento Competitivo/fisiologia , Adulto , Desempenho Atlético/psicologia , Ciclismo/psicologia , Tomada de Decisões , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Fatores de Tempo , Adulto Jovem
7.
Int J Sports Med ; 40(14): 886-896, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31648353

RESUMO

Exercise physiological responses can be markedly affected by acute hypoxia. We investigated cardiac autonomic and physiological responses to different hypoxic training protocols. Thirteen men performed three exercise sessions (5×5-min; 1-min passive recovery): normoxic exercise at 80% of the power output (PO) at the first ventilatory threshold (N), hypoxic exercise (FiO2=14.2%) with the same PO as N (HPO) and hypoxic exercise at the same heart rate (HR) as N (HHR). PO was lower in HHR (21.1±9.3%) compared to N and HPO. Mean HR was higher in HPO (154±11 bpm, p<0.01) than N and HHR (139±10 vs. 138±9 bpm; p=0.80). SpO2 was reduced (p<0.01) to a similar extent (p>0.05) in HPO and HHR compared to N. HR recovery (HRR) and HR variability indices were similar in N and HHR (p>0.05) but reduced in HPO (p<0.05), mirroring a delayed parasympathetic reactivation. Blood lactate and ventilation were similar in N and HHR (p>0.05) and increased in HPO (p<0.001). During recovery oxygen consumption and ventilation were similar in N and HHR (p>0.05) and increased in HPO (p<0.01). Moderate HR-matched hypoxic exercise triggers similar cardiac autonomic and physiological responses to normoxic exercise with a reduced mechanical load. On the contrary, the same absolute intensity exercise in hypoxia is associated with increased exercise-induced metabolic stress and delayed cardiac autonomic recovery.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Exercício/fisiologia , Coração/inervação , Hipóxia/fisiopatologia , Adulto , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Taxa Respiratória , Adulto Jovem
8.
Int J Sports Med ; 40(14): 879-885, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31574544

RESUMO

The potential anti-fatigue and performance benefits of hydrogen rich water (HRW) have resulted in increased research interest over the past 5 years. The aim of this study was to assess physiological and perceptual responses to an incremental exercise protocol after administration of 600 ml HRW within 30 min before exercise. This randomized, double blinded placebo-controlled cross over study included twelve healthy males aged 27.1±4.9 years. The exercise protocol consisted of a 10 min warm-up at 1.0 W.kg-1, followed by 8 min at 2.0, 3.0, and 4.0 W.kg-1, respectively. Cardio-respiratory variables, lactate and ratings of perceived exertion (RPE) were assessed in the last minute of each step. A significantly lower blood lactate was found with HRW (4.0±1.6 and 8.9±2.2 mmol.l-1) compared to Placebo (5.1±1.9 and 10.6±3.0 mmol.l-1) at 3.0, and 4.0 W.kg-1, respectively. Ventilatory equivalent for oxygen and RPE exhibited significantly lower values with HRW (32.3±7.2, and 17.8±1.2 points, respectively) compared to Placebo (35.0±8.4, and 18.5±0.8 points, respectively) at 4 W.kg-1. To conclude, acute pre-exercise supplementation with HRW reduced blood lactate at higher exercise intensities, improved exercise-induced perception of effort, and ventilatory efficiency.


Assuntos
Ingestão de Líquidos , Exercício/fisiologia , Hidrogênio , Ácido Láctico/sangue , Percepção/fisiologia , Esforço Físico/fisiologia , Respiração , Água/química , Adulto , Método Duplo-Cego , Exercício/psicologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Fadiga Muscular/fisiologia , Consumo de Oxigênio/fisiologia , Adulto Jovem
9.
Medicine (Baltimore) ; 98(41): e17400, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31593091

RESUMO

INTRODUCTION: Cardiac autonomic modulation is an important marker of cardiovascular health and the practice of physical activity is a fundamental tool for good maintenance or increments in this marker. However, it is not clear in the literature whether different intensities and different domains of physical activity are related in the same way to cardiac autonomic modulation. OBJECTIVES: This randomized epidemiologic study will examine the relationship between cardiac autonomic modulation and different intensities and domains of physical activity in a representative sample of adults. METHODS: The sample of study will consist of 252 subjects aged from 18 years and above. The sample will be randomized through census sectors in which the neighborhoods, streets, and houses will also be randomized. Cardiac autonomic modulation will be assessed by heart rate variability and the intensity (mild, moderate, intense) of physical activity will be evaluated by means of accelerometers, while the different domains of physical activity (physical activity at work, occupational activities) will be evaluated through a questionnaire. The relationship between cardiac autonomic modulation and different physical activity intensities, as well as the different domains will be analyzed by linear regression, considering a statistical significance of 5% and a 95% confidence interval. This research protocol is registered in ClinicalTrials.gov at number NCT03986879.


Assuntos
Acelerometria/estatística & dados numéricos , Sistema Nervoso Autônomo/fisiologia , Exercício/fisiologia , Coração/fisiologia , Esforço Físico/fisiologia , Adolescente , Adulto , Feminino , Frequência Cardíaca/fisiologia , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Estudos Observacionais como Assunto , Inquéritos e Questionários , Adulto Jovem
10.
J Sports Sci ; 37(23): 2691-2701, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31526108

RESUMO

This study investigated effects of total sleep deprivation on self-paced endurance performance, and heart rate (HR) indices of athletes' "readiness to perform". Endurance athletes (n = 13) completed a crossover experiment comprising a normal sleep (NS) and sleep deprivation (SD) condition. Each required completion of an endurance time-trial (TT) on consecutive days (D1, D2) separated by normal sleep or total sleep deprivation. Finishing time, perceived exertion (RPE), mood, psychomotor vigilance (PVT), and HR responses were assessed. Time on D2 of SD was 10% slower than D2 of NS (64 ± 7 vs 59 ± 4 min, P < 0.01), and 11% slower than D1 of SD (58 ± 5 min, P < 0.01). Subjective to objective (RPE:mean HR) intensity ratio was higher on D2 of SD compared with D2 of NS and D1 of SD (P < 0.01). Mood disturbance and PVT mean response time increased on D2 of SD compared with D2 of NS and D1 of SD. Anaerobic threshold and change in TT time were correlated (R = -0.73, P < 0.01). Sleep helps to optimise endurance performance. Subjective to objective intensity ratios appear sensitive to effects of sleep on athletes' readiness. Research examining more subtle sleep manipulation is required.


Assuntos
Ciclismo/fisiologia , Frequência Cardíaca/fisiologia , Resistência Física/fisiologia , Privação do Sono/fisiopatologia , Actigrafia/instrumentação , Adulto , Afeto/fisiologia , Ciclismo/psicologia , Estudos Cross-Over , Teste de Esforço , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Tempo de Reação/fisiologia , Dispositivos Eletrônicos Vestíveis
11.
J Strength Cond Res ; 33(10): 2622-2628, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31403576

RESUMO

Walker, AJ, McFadden, BA, Sanders, DJ, Rabideau, MM, Hofacker, ML, and Arent, SM. Biomarker response to a competitive season in Division I female soccer players. J Strength Cond Res 33(10): 2622-2628, 2019-The purpose of this study was to evaluate effects of training load (TL) on performance and biomarkers of health, performance, and recovery in Division I female soccer players throughout a competitive season. Subjects (N = 25, Mage = 20 ± 1.1 years) were monitored before the start of preseason and every 4-weeks thereafter (T1-T5). A battery of performance tests was administered before the start of preseason (P1) and end-of-season (P2), including body composition (percent body fat [%BF], fat free mass [FFM], and fat mass), vertical jump (VJ), and VO2max. Blood draws were conducted at every time point (T1-T5) to assess free and total cortisol (CORTF and CORTT), prolactin (PRL), T3, IL-6, creatine kinase (CK), sex-hormone binding globulin, omega-3 (n-3FA), vitamin-D (Vit-D), iron (Fe), hematocrit (HcT), ferritin (Fer), percent saturation (%Sat), and total iron-binding capacity (TIBC). Daily exercise energy expenditure (EEE) and TL were determined. There were significant declines in VO2max, VJ, weight, and %BF from P1-P2 (p < 0.05) with no significant differences in FFM. Training load and EEE significantly decreased from T1-T3 (p < 0.05). Significant increases were seen in CORTT, CORTF, PRL, T3, IL-6, CK, and TIBC throughout the season (p < 0.05). Significant decreases were seen in n-3FA, Fe, Fer, %Sat, and Hct throughout the season (p < 0.05). Female athletes experience significant physiological changes following high TL and EEE associated with preseason and appear to be further exacerbated by the cumulative effects of the season. Unique insights provided by biomarkers enable athletes and coaches to be cognizant of the physiological changes that are occurring throughout the season.


Assuntos
Desempenho Atlético/fisiologia , Exercício/fisiologia , Esforço Físico/fisiologia , Futebol/fisiologia , Adolescente , Biomarcadores/sangue , Composição Corporal , Peso Corporal , Creatina Quinase/sangue , Teste de Esforço , Ácidos Graxos Ômega-3/sangue , Feminino , Ferritinas/sangue , Hematócrito , Humanos , Hidrocortisona/sangue , Interleucina-6/sangue , Ferro/sangue , Oxigênio/sangue , Consumo de Oxigênio , Condicionamento Físico Humano/fisiologia , Prolactina/sangue , Globulina de Ligação a Hormônio Sexual/metabolismo , Tri-Iodotironina/sangue , Vitamina D/sangue , Adulto Jovem
12.
BMC Public Health ; 19(1): 1100, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31412839

RESUMO

BACKGROUND: Workers with physically demanding work may be at risk for injury, illness or other adverse health outcomes due to exposure to different occupational hazards, especially at higher age. Sensor technology applications may be useful in the workplace to unobtrusively measure and monitor work exposures and provide workers with real-time feedback or access to data on demand. Many aspects might impede the implementation of sensor technology applications in the workplace, which should be taken into consideration for a successful implementation. Moreover, needs and preferences of workers regarding the use of sensor technology applications during work performance need to be identified. Therefore, the aim of this study was to identify worker needs and preferences regarding the use of sensor technology applications in the workplace. METHODS: Four on-site focus group sessions were conducted in four different companies among workers with physically demanding work (n = 30). Semi-structured interview schedules were used to identify which work exposures should be measured, by which kind of sensor technology applications, under which (pre)conditions, how to motivate long-term use of sensor technology applications, and which type of feedback is preferred. For data analysis, a content-analysis with an inductive approach was performed. RESULTS: Participants mentioned that they want to use wearable sensor technology applications to measure and monitor physical job demands, occupational heat stress, noise and fatigue. Factors associated with quality, comfort and perceived ease of use were identified as potential barriers for implementation in the workplace. Long-term motivation was attributed to the ability to manage and monitor work exposures, positive feedback and data ownership. Participants indicated a need to both receive real-time feedback and access to data on demand. CONCLUSIONS: Sensor technology applications may support workers with physically demanding work to measure and monitor their work exposures. Potential barriers for implementation such as privacy aspects and quality, comfort and perceived ease of use of sensor technology applications need to be well considered to ensure successful implementation of sensor technology applications in the workplace.


Assuntos
Promoção da Saúde/métodos , Monitorização Ambulatorial/instrumentação , Saúde do Trabalhador , Esforço Físico/fisiologia , Trabalho/fisiologia , Adulto , Grupos Focais , Humanos , Masculino , Pessoa de Meia-Idade , Determinação de Necessidades de Cuidados de Saúde , Dispositivos Eletrônicos Vestíveis
13.
Eur J Appl Physiol ; 119(9): 2083-2094, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31372804

RESUMO

PURPOSE: The mediators of the perception of effort during exercise are still unclear. The aim of the present study was to examine physiological responses during runs using a rating of perceived exertion (RPE)-clamp model at the RPE corresponding to the gas exchange threshold (RPEGET) and 15% above GET (RPEGET+15%) to identify potential mediators and performance applications for RPE during treadmill running. METHODS: Twenty-one runners ([Formula: see text]max = 51.7 ± 8.3 ml kg-1 min-1) performed a graded exercise test to determine maximal oxygen consumption and the RPE associated with GET and GET + 15% followed by randomized 60 min RPE-clamp runs at RPEGET and RPEGET+15%. Mean differences for [Formula: see text], heart rate (HR), minute ventilation ([Formula: see text]), respiratory frequency ([Formula: see text], respiratory exchange ratio (RER), and velocity were compared across each run. RESULTS: After minute 14, [Formula: see text], RER and velocity did not differ across conditions, but decreased across time (p < 0.05). There was a significant (p < 0.05) condition × time interaction for [Formula: see text], where values were significantly higher during RPE-clamp runs at RPEGET+15% and decreased across time in both conditions. There were no differences across condition or time for HR, and only small difference between conditions for [Formula: see text]. CONCLUSIONS: HR and [Formula: see text] may play a role in mediating the perception of effort, while [Formula: see text], RER, and [Formula: see text] may not. Although HR and [Formula: see text] may mediate the maintenance of a perceptual intensity, they may not be sensitive to differentiate perceptual intensities at GET and GET + 15%. Thus, prescribing exercise using an RPE-clamp model may only reflect a sustainable [Formula: see text] within the moderate intensity domain.


Assuntos
Exercício/fisiologia , Esforço Físico/fisiologia , Corrida/fisiologia , Adulto , Teste de Esforço/métodos , Terapia por Exercício/métodos , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Troca Gasosa Pulmonar/fisiologia , Taxa Respiratória/fisiologia , Ventilação/métodos , Adulto Jovem
14.
J Sports Sci ; 37(23): 2676-2684, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31418323

RESUMO

The velocity and magnitude in which the eccentric phase of an exercise is completed directly affects performance during the concentric phase. Therefore, the purpose of this research was to investigate the effects of eccentric phase duration on concentric outcomes at 60% and 80% of one-repetition maximum (1RM) in the squat and bench press. Sixteen college-aged, resistance-trained males completed 1RM testing, established normative eccentric durations, and performed fast (0.75 times normative) and slow (2.0 times normative) metronome-controlled eccentric duration repetitions. Outcome measures assessed during the concentric phase were: average concentric velocity (ACV), peak concentric velocity (PCV), rating of perceived exertion (RPE), range of motion (ROM), and barbell path. Eccentric duration was significantly and inversely correlated with ACV at 60% (r = -0.408, p = 0.004) and 80% (r = -0.477, p = 0.001) of 1RM squat. At 60% of 1RM squat, both fast and slow eccentric conditions produced greater (p < 0.001) PCV than normative duration with fast also producing greater PCV than slow (p = 0.044). Eccentric duration had no impact on RPE, ROM, or barbell path. Our results report for the first time that resistance-trained males performing a deliberately faster eccentric phase may enhance their own squat and bench press performance.


Assuntos
Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Levantamento de Peso/fisiologia , Fenômenos Biomecânicos , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Adulto Jovem
15.
Int J Sports Med ; 40(11): 739-743, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31437860

RESUMO

This study examined the relationship between PhA and short-term maximal intensity efforts in soccer players, and was conducted in 99 male soccer players, ages 19-36 years. Bioelectrical impedance was used to assess body fat, fat free mass (FFM) and PhA (phase angle). Running Anaerobic Sprint Test (RAST) was used to evaluate physical performance. Food consumption was assessed through the 24-hour dietary recall method. Pearson correlation and multiple regressions were used for statistical analysis. Phase angle exhibited a positive relationship with maximum power (ß=0.66; P<0.001), even after adjustment for the co-variables FFM and body fat (ß=0.52; P=0.02). Phase angle was inversely related with fatigue index (ß=- 0.61; P=0.04), even after adjusting for FFM (ß=- 0.70; P=0.020). Our results indicated that independently of FFM and body fat, PhA was inversely associated with fatigue index and positively related with maximum power, revealing the PhA appeared as a valid predictor of fatigue.


Assuntos
Desempenho Atlético/fisiologia , Impedância Elétrica , Esforço Físico/fisiologia , Futebol/fisiologia , Adulto , Composição Corporal , Estudos Transversais , Dieta , Humanos , Masculino , Fadiga Muscular/fisiologia , Adulto Jovem
16.
J Sports Sci ; 37(21): 2506-2512, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31362579

RESUMO

The study assesses the test-retest reliability of movement and physiological measures during a simulated rugby match that employed activities performed in a stochastic order. Twenty male rugby players (21.4 ± 2.1 y) completed two trials of a 2 × 23 min rugby movement simulation protocol during which the order of events was performed in a stochastic order, with 7-10 days between trials. Movement characteristics, heart rate (HR), RPE, maximum voluntary contraction (MVC), voluntary activation (VA%) of the quadriceps, Stroop test and subjective task load rating (NASA-TLX) were measured. The most reliable measures of external load was relative distance (typical error [TE] and CV% = 1.5-1.6 m min-1 and 1.4-1.5%, respectively), with all other movement characteristics possessing a CV% <5%. The most reliable measure of internal load, neuromuscular function and perceptual measures were for %HRmax (TE and CV% = 1.4-1.7% and 1.4-2.1%, respectively), MVC before (TE and CV% = 10.8-14.8 N·m and 3.8-4.6%, respectively), and average RPE (TE and CV% = 0.5-0.8 AU and 3.6-5.5%, respectively). The Stroop test, NASA-TLX and blood lactate produced the least reliable measures (CV% >5%). Future studies can confidently examine changes in several perceptual, neuromuscular, physiological and movement measures related to rugby activity using stochastic movements.


Assuntos
Desempenho Atlético/fisiologia , Desempenho Atlético/psicologia , Cognição/fisiologia , Futebol Americano/fisiologia , Futebol Americano/psicologia , Movimento/fisiologia , Músculo Quadríceps/fisiologia , Comportamento Competitivo/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Contração Muscular/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Processos Estocásticos , Teste de Stroop , Análise e Desempenho de Tarefas , Adulto Jovem
18.
Arch. med. deporte ; 36(192): 215-219, jul.-ago. 2019. ilus, tab, graf
Artigo em Espanhol | IBECS | ID: ibc-185177

RESUMO

Controlar las variables de entrenamiento es vital para garantizar las adaptaciones deseadas en el entrenamiento de fuerza, siendo la intensidad especialmente importante para mejorar la fuerza máxima y el RFD. La velocidad de ejecución ha resultado ser la mejor variable para monitorizar la intensidad del entrenamiento de fuerza, en particular las pérdidas de velocidad relacionadas con la fatiga. Sin embargo, existen impedimentos materiales para poder utilizar esta variable. Por tanto, el objetivo de este trabajo es analizar la relación entre el RPE y las pérdidas de velocidad como alternativa para controlar el entrenamiento. Se midió a 5 sujetos (4 hombres y 1 mujer) pertenecientes a la selección española de lucha libre olímpica un total de 15 series de press de banca (3 series/sujeto), de las cuales solo 14 se incluyeron en el análisis estadístico por incumplir una de ellas el protocolo, con 3 cargas relativas distintas (5 series/carga) y una pérdida de velocidad entre 20%-32%. Las variables dependientes fueron: RPE, la pérdida de velocidad, el número de repeticiones realizadas en cada serie y velocidad de la mejor repetición de cada serie. Se analizaron las correlaciones entre las variables RPE-pérdida de velocidad; RPE-número de repeticiones; RPE-velocidad mejor repetición, obteniéndose solamente correlación significativa (r Pearson 0,843; P < 0,001) entre el RPE y la pérdida de velocidad; la correlaciones entre el RPE-número de repeticiones y RPE-velocidad mejor repetición no mostraron significación estadística. Estos resultados podrían indicar la posibilidad de gestionar la fatiga y la intensidad del entrenamiento utilizando la relación RPE-pérdida de velocidad, aunque es necesario llevar a cabo estudios similares con tamaños muestrales mayores que refuercen los resultados obtenidos en este estudio


Controlling the training variables is vital to ensure the desired adaptations in resistance training; intensity is the most important variable to improve maximum strength and rate of force development (RFD). The movement velocity has shown to be the best variable to monitor the intensity of resistance training, in particular the velocity loss related to fatigue. However, there are material impediments to use this variable. Therefore, the aim of this paper is to analyze the relationship between RPE and velocity losses as an alternative to control training. Sample included 5 subjects (4 men and 1 woman) from the Spanish Olympic Wrestling team who performed a total of 15 sets of bench press (3 set/subject), of which only 14 were included in the statistical analysis for breaching one of them the protocol, with 3 different relative loads (5 set/load) and a velocity loss between 20%-32%. The dependent variables were: RPE, the velocity loss, the number of repetitions performed in each set and the velocity of the best repetition of each set. The correlations between the RPE-velocity loss; RPE-number of repetitions; and RPE-velocity best repetition variables were analyzed, obtaining only significant correlation (r Pearson 0.843, P < 0.001) between the RPE and the velocity loss; correlations between RPE-number of repetitions; and RPE-velocity best repetition did not show statistical significance . The results of the present work could indicate the possibility of managing fatigue and controlling training intensity using the RPE-velocity loss relationship, although it is necessary to carry out similar studies with larger sample sizes that reinforce the results of this study


Assuntos
Humanos , Masculino , Feminino , Adulto , Medição de Velocidade/métodos , Treinamento de Resistência/métodos , Movimento/fisiologia , Esforço Físico/fisiologia , Exercício/fisiologia , Análise Estatística , Protocolos
19.
Medicina (Kaunas) ; 55(8)2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31344963

RESUMO

Limited evidence is available on optimal patient effort and degree of assistance to achieve preferable changes during robot-assisted training (RAT) for spinal cord injury (SCI) patients with spasticity. To investigate the relationship between patient effort and robotic assistance, we performed training using an electromyography-based robotic assistance device (HAL-SJ) in an SCI patient at multiple settings adjusted to patient effort. In this exploratory study, we report immediate change in muscle contraction patterns, patient effort, and spasticity in a 64-year-old man, diagnosed with cervical SCI and with American Spinal Injury Association Impairment Scale C level and C4 neurological level, who underwent RAT using HAL-SJ from post-injury day 403. Three patient effort conditions (comfortable, somewhat hard, and no-effort) by adjusting HAL-SJ's assists were set for each training session. Degree of effort during flexion and extension exercise was assessed by visual analog scale, muscle contraction pattern by electromyography, modified Ashworth scale, and maximum elbow extension and flexion torques, immediately before and after each training session, without HAL-SJ. The amount of effort during training with the HAL-SJ at each session was evaluated. The degree of effort during training can be set to three effort conditions as we intended by adjusting HAL-SJ. In sessions other than the no-effort setting, spasticity improved, and the level of effort was reduced immediately after training. Spasticity did not decrease in the training session using HAL-SJ with the no-effort setting, but co-contraction further increased during extension after training. Extension torque was unchanged in all sessions, and flexion torque decreased in all sessions. When performing upper-limb training with HAL-SJ in this SCI patient, the level of assistance with some effort may reduce spasticity and too strong assistance may increase co-contraction. Sometimes, a patient's effort may be seemingly unmeasurable; hence, the degree of patient effort should be further measured.


Assuntos
Espasticidade Muscular/terapia , Treinamento de Resistência/normas , Procedimentos Cirúrgicos Robóticos/normas , Extremidade Superior/fisiopatologia , Medula Cervical/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esforço Físico/fisiologia , Amplitude de Movimento Articular/fisiologia , Treinamento de Resistência/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Procedimentos Cirúrgicos Robóticos/reabilitação
20.
J Sports Sci ; 37(22): 2530-2537, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31345111

RESUMO

The aims of this study were (a) to compare players' physical demands between different playing positions in elite U18 basketball games and (b) to identify different clusters of performance. Data were collected from 94 male subjects (age: 17.4 ± 0.7 years), competing in a Euroleague Basketball Tournament. Guards covered a greater relative distance than centres and forwards (small to moderate effect). Forwards and guards had more peak accelerations, high accelerations and high decelerations than centres (moderate to large effects). A cluster analysis allowed to classify all cases into three different groups (Lower, Medium and Higher activity demands), containing 37.4%, 52.8% and 9.8% of the cases, respectively. The high accelerations, high decelerations, peak accelerations and total distance covered were the variables that most contributed to classify the players into the new groups. The percentage of cases distributed in the clusters according to playing position, game type (worst vs worst, mixed opposition, best vs best) and team were different. Centres have lower physical demands specially related with the number of accelerations and decelerations at high intensity and the peak acceleration when compared with guards. Each team has a different activity profile, that does not seem to influence the tournament outcome.


Assuntos
Desempenho Atlético/fisiologia , Basquetebol/fisiologia , Comportamento Competitivo/fisiologia , Esforço Físico/fisiologia , Aceleração , Adolescente , Humanos , Masculino , Destreza Motora/fisiologia , Estudos de Tempo e Movimento
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