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1.
Sports Biomech ; 19(6): 723-737, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32942954

RESUMO

The aim of this study was to understand if and how surface-induced vibrations and road bike damping affect short-term neuromuscular performance in cycling. Thirty cyclists (mass 75.9 ± 8.9 kg, height 1.82 ± 0.05 m, Vo2max 63.0 ± 6.8 ml/min/kg) performed steady-state and maximum effort tests with and without vibration exposure (front dropout: 44 Hz, 4.1 mm; rear dropout: 38 Hz, 3.5 mm) on a damped and a nondamped bike. Transmitted accelerations to the musculoskeletal system, activation of lower extremity muscles (gast. med., soleus, vast. med., rec. fem.) and upper body muscles (erec. spinae, deltoideus, tric. brachii), oxygen uptake, heart rate and crank power output were measured. The main findings indicate a transmission of vibration to the whole body, but since no major propulsive muscles increase their activation with vibration, the systemic energy demand increases only marginally with vibration. Damping reduces vibrations at the upper body, which indicates an increase in comfort, but has no effect on the vibration transfer to the lower extremities. Therefore, road bike damping does not affect neuromuscular response of the propulsive muscle groups and energy demand. Consequently, short-term power output does not increase with damping.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Meio Ambiente , Músculo Esquelético/fisiologia , Vibração , Aceleração , Fenômenos Biomecânicos , Estudos Transversais , Frequência Cardíaca/fisiologia , Humanos , Extremidade Inferior/fisiologia , Masculino , Músculo Esquelético/inervação , Consumo de Oxigênio/fisiologia , Tronco/fisiologia , Extremidade Superior/fisiologia
2.
PLoS One ; 15(8): e0237768, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813742

RESUMO

INTRODUCTION: In cycling, the utilization of the drops position (i.e. the lowest handlebar position relative to the ground) allows for reduced frontal area, likely improved aerodynamics and thus performance compared to the tops (i.e. the position producing the most upright trunk). The reduced trunk angle during seated submaximal cycling has been shown to influence cardiorespiratory factors but the effects on pedalling forces and joint specific power are unclear. The purpose of this study was to investigate the effect of changing handgrip position on joint specific power and cycling kinematics at different external work rates in recreational and professional cyclists. METHOD: Nine professional and nine recreational cyclists performed cycling bouts using three different handgrip positions and three external work rates (i.e. 100W, 200W and external work rate corresponding to the lactate threshold (WRlt)). Joint specific power was calculated from kinematic measurements and pedal forces using 2D inverse dynamics. RESULTS: We found increased hip joint power, decreased knee joint power and increased peak crank torque for the professional cyclist compared to the recreational cyclists, but only at WRlt where the professional cyclists were working at a higher external work rate. There was no main effect of changing handgrip position on any joint, but there was a small interaction effect of external work rate and handgrip position on hip joint power contribution (Generalized eta squared (ηg2) = 0.012). At 100W, changing handgrip position from the tops to the drops decreased the hip joint contribution (-2.0 ± 3.9 percentage points (pct)) and at the WRlt, changing handgrip position increased the hip joint power (1.6 ± 3.1 pct). There was a small effect of handgrip position with the drops leading to increased peak crank torque (ηg2 = 0.02), increased mean dorsiflexion (ηg2 = 0.05) and increased hip flexion (ηg2 = 0.31) compared to the tops. DISCUSSION: The present study demonstrates that there is no main effect of changing handgrip position on joint power. Although there seems to be a small effect on hip joint power when comparing across large ranges in external work rate, any potential negative performance effect would be outweighed by the aerodynamic benefit of the drops position.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Postura/fisiologia , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Mãos/fisiologia , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Torque , Adulto Jovem
3.
Artigo em Inglês | MEDLINE | ID: mdl-32748826

RESUMO

Endurance physical exercise is accompanied by subjective perceptions of exertion (reported perceived exertion, RPE), emotional valence, and arousal. These constructs have been hypothesized to serve as the basis for the exerciser to make decisions regarding when to stop, how to regulate pace, and whether or not to exercise again. In dual physical-cognitive tasks, the mental (executive) workload generated by the cognitive task has been shown to influence these perceptions, in ways that could also influence exercise-related decisions. In the present work, we intend to replicate and extend previous findings that manipulating the amount of executive load imposed by a mental task, performed concomitantly with a submaximal cycling session, influenced emotional states but not perceived exertion. Participants (experienced triathletes) were asked to perform a submaximal cycling task in two conditions with different executive demands (a two-back version of the n-back task vs. oddball) but equated in external physical load. Results showed that the higher executive load condition elicited more arousal and less positive valence than the lower load condition. However, both conditions did not differ in RPE. This experimental dissociation suggests that perceived exertion and its emotional correlates are not interchangeable, which opens the possibility that they could play different roles in exercise-related decision-making.


Assuntos
Nível de Alerta/fisiologia , Ciclismo/fisiologia , Função Executiva/fisiologia , Exercício Físico , Esforço Físico/fisiologia , Afeto , Emoções , Humanos , Carga de Trabalho
4.
PLoS One ; 15(7): e0235567, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628697

RESUMO

In the absence of a ⩒o2-work-rate plateau, debate continues regarding the best way to verify that the peak ⩒o2 achieved during incremental exercise (⩒o2peak) is the "true ⩒o2max." Oft-used "secondary criteria" have been questioned in conjunction with the contention that a severe-intensity constant-work-rate "verification bout" should be considered the "gold standard." The purpose of this study was to compare the ⩒o2peak during ramp incremental cycling (RAMP-INC) by a heterogeneous (with respect to body composition and sex) cohort of sedentary individuals with the ⩒o2peak during severe-intensity constant-work-rate cycling (CWR) performed after RAMP-INC at the highest work rate achieved. A secondary purpose was to determine the degree to which traditional and newly-proposed age-dependent secondary criteria (RER, HR) identified RAMP-INC which CWR confirmed were characterized by a submaximal ⩒o2peak. Thirty-five healthy male (n = 19: 33.4 ± 6.3 yrs) and female (26.8 ± 3.6 yrs) sedentary participants performed RAMP-INC followed by CWR. The ⩒o2peak values from the two tests were correlated (r = 0.96; p < 0.01; mean CV = 24%); however, ⩒o2peak for CWR was significantly greater (29.6 ± 7.2 v. 28.6 ± 6.8 mL∙min-1∙kg-1; p < 0.01) with a mean bias of 0.98 mL∙min-1∙kg-1 (z = -2.9, p < 0.01). Both traditional and newly-proposed criterion values for RER were achieved during RAMP-INC by 33 of 35 participants (including 21 of 23 who registered a higher ⩒o2peak on CWR). The traditional HR criterion value was achieved on only seven tests (three of which were confirmed to be characterized by a submaximal ⩒o2peak) while use of less stringent newly-proposed criteria resulted in acceptance of an additional seven tests of which five were confirmed to be submaximal. Severe-intensity CWR to limit of tolerance indicates that RAMP-INC underestimates ⩒o2max in sedentary individuals and both traditional and newly-proposed secondary criteria are ineffective for identifying such tests.


Assuntos
Ciclismo/fisiologia , Consumo de Oxigênio , Comportamento Sedentário , Trabalho , Adulto , Estudos de Coortes , Feminino , Humanos , Masculino
5.
J Sports Sci ; 38(17): 2021-2034, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32552580

RESUMO

Heart rate (HR), when combined with accelerometry, can dramatically improve estimates of energy expenditure and sleep. Advancements in technology, via the development and introduction of small, low-cost photoplethysmography devices embedded within wrist-worn consumer wearables, have made the collection of heart rate (HR) under free-living conditions more feasible. This systematic review and meta-analysis compared the validity of wrist-worn HR estimates to a criterion measure of HR (electrocardiography ECG or chest strap). Searches of PubMed/Medline, Web of Science, EBSCOhost, PsycINFO, and EMBASE resulted in a total of 44 articles representing 738 effect sizes across 15 different brands. Multi-level random effects meta-analyses resulted in a small mean difference (beats per min, bpm) of -0.40 bpm (95 confidence interval (CI) -1.64 to 0.83) during sleep, -0.01 bpm (-0.02 to 0.00) during rest, -0.51 bpm (-1.60 to 0.58) during treadmill activities (walking to running), while the mean difference was larger during resistance training (-7.26 bpm, -10.46 to -4.07) and cycling (-4.55 bpm, -7.24 to -1.87). Mean difference increased by 3 bpm (2.5 to 3.5) per 10 bpm increase of HR for resistance training. Wrist-worn devices that measure HR demonstrate acceptable validity compared to a criterion measure of HR for most common activities.


Assuntos
Frequência Cardíaca/fisiologia , Fotopletismografia/instrumentação , Dispositivos Eletrônicos Vestíveis , Acelerometria , Atividades Cotidianas , Ciclismo/fisiologia , Metabolismo Energético/fisiologia , Humanos , Reprodutibilidade dos Testes , Treinamento de Resistência , Descanso/fisiologia , Corrida/fisiologia , Sono/fisiologia , Caminhada/fisiologia , Punho
6.
J Sport Health Sci ; 9(3): 258-264, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32444150

RESUMO

BACKGROUND: Q-Factor (QF), or the inter-pedal width, in cycling is similar to step-width in gait. Although increased step-width has been shown to reduce peak knee abduction moment (KAbM), no studies have examined the biomechanical effects of increased QF in cycling at different workrates in healthy participants. METHODS: A total of 16 healthy participants (8 males, 8 females, age: 22.4 ± 2.6 years, body mass index: 22.78 ± 1.43 kg/m2, mean ± SD) participated. A motion capture system and customized instrumented pedals were used to collect 3-dimensional kinematic (240 Hz) and pedal reaction force (PRF) (1200 Hz) data in 12 testing conditions: 4 QF conditions-Q1 (15.0 cm), Q2 (19.2 cm), Q3 (23.4 cm), and Q4 (27.6 cm)-under 3 workrate conditions-80 watts (W), 120 W, and 160 W. A 3 × 4 (QF × workrate) repeated measures of analysis of variance were performed to analyze differences among conditions (p < 0.05). RESULTS: Increased QF increased peak KAbM by 47%, 56%, and 56% from Q1 to Q4 at each respective workrate. Mediolateral PRF increased from Q1 to Q4 at each respective workrate. Frontal-plane knee angle and range of motion decreased with increased QF. No changes were observed for peak vertical PRF, knee extension moment, sagittal plane peak knee joint angles, or range of motion. CONCLUSION: Increased QF increased peak KAbM, suggesting increased medial compartment loading of the knee. QF modulation may influence frontal-plane joint loading when using stationary cycling for exercise or rehabilitation purposes.


Assuntos
Ciclismo/fisiologia , Articulação do Joelho/fisiologia , Equipamentos Esportivos , Artralgia/fisiopatologia , Fenômenos Biomecânicos , Desenho de Equipamento , Feminino , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Amplitude de Movimento Articular , Estudos de Tempo e Movimento , Adulto Jovem
7.
Sportis (A Coruña) ; 6(2): 286-307, mayo 2020. tab
Artigo em Espanhol | IBECS | ID: ibc-193346

RESUMO

El objetivo del estudio fue describir el tipo de desplazamiento utilizado por los adolescentes de Huesca para ir y volver del centro educativo, así como analizar su asociación con el género y el curso académico. Participaron 1.709 adolescentes (Medad=14.20; DT=1.56; 51.7% chicas) de 1º de Educación Secundaria Obligatoria (ESO) a 1º de Bachillerato. Los estudiantes cumplimentaron un cuestionario sobre el modo habitual de desplazamiento en la ida y vuelta al instituto. Los resultados señalaron que un 76.4% de los adolescentes se desplazaba activamente (i.e., andando o en bicicleta) tanto en la ida como en la vuelta. De los adolescentes que se desplazaban activamente, un 78.5% en la ida y un 81.7% en la vuelta lo hacía caminando. En relación con el género, se encontró una asociación positiva entre ir andando al centro educativo y ser chica, así como entre ir en bicicleta y ser chico. En relación con el curso académico, desplazarse andando al centro educativo se asoció positivamente con 4º de ESO y negativamente con 1º de Bachillerato. Asimismo, desplazarse en bicicleta se asoció positivamente con 1º de Bachillerato y negativamente con 3º de ESO. Aunque la mayoría de los adolescentes se desplaza activamente al instituto, parece necesario promover programas escolares que incentiven el desplazamiento activo de los jóvenes dada las características favorables de movilidad de la ciudad de Huesca. De igual modo, parece necesaria la promoción de la bicicleta como modo de desplazamiento al instituto, especialmente en las chicas y en los estudiantes de ESO


The aim of this study was to describe the usual mode of commuting to and from school in adolescents of Huesca and its association with gender and academic year. A total of 1,709 adolescents (Mage=14.20; DT=1.56; 51.7% girls) from 1st-year of middle school [Spanish acronym, ESO] to 1st-year high school) participated in this study. A questionnaire of the usual mode of commuting to and from school was self-reported by students. Results showed that 76.4% of adolescents commuted actively (i.e., walking or cycling) to and from school. Of the adolescents who commute actively to and from school, 78.5% to school and 81.7% from school walked. Regarding gender, a positive association was found between walking to and from school and being a girl, as well as between cycling and being a boy. Regarding the grade level, walking to and from school was positively associated with adolescents in 4th of middle school and negatively with 1st-year high school. On the other hand, travelling by bicycle both routes was positively associated with 1st-year of high school and negatively with 3rd year of middle school. Although the majority of adolescents from Huesca commuted actively to and from school, it seems that active school transport interventions are necessary, given the favorable characteristics of the city of Huesca. Similarly, it seems necessary to promote cycling as a means of transport to and from school, especially among girls and secondary education students


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Caminhada/fisiologia , Comportamentos Relacionados com a Saúde , Ciclismo/fisiologia , Transportes/métodos , Caminhada/psicologia , Estudantes/estatística & dados numéricos , Inquéritos e Questionários , Ciclismo/psicologia , Estudos Transversais , Comportamento Sedentário , Transportes/estatística & dados numéricos , Serviços de Saúde Escolar
8.
J Sports Sci ; 38(13): 1496-1505, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32252598

RESUMO

A means of quantifying continuous, free-living energy expenditure (EE) would advance the study of bioenergetics. The aim of this study was to apply a non-linear, machine learning algorithm (random forest) to predict minute level EE for a range of activities using acceleration, physiological signals (e.g., heart rate, body temperature, galvanic skin response), and participant characteristics (e.g., sex, age, height, weight, body composition) collected from wearable devices (Fitbit charge 2, Polar H7, SenseWear Armband Mini and Actigraph GT3-x) as potential inputs. By utilising a leave-one-out cross-validation approach in 59 subjects, we investigated the predictive accuracy in sedentary, ambulatory, household, and cycling activities compared to indirect calorimetry (Vyntus CPX). Over all activities, correlations of at least r = 0.85 were achieved by the models. Root mean squared error ranged from 1 to 1.37 METs and all overall models were statistically equivalent to the criterion measure. Significantly lower error was observed for Actigraph and Sensewear models, when compared to the manufacturer provided estimates of the Sensewear Armband (p < 0.05). A high degree of accuracy in EE estimation was achieved by applying non-linear models to wearable devices which may offer a means to capture the energy cost of free-living activities.


Assuntos
Acelerometria/instrumentação , Atividades Cotidianas , Metabolismo Energético/fisiologia , Exercício Físico/fisiologia , Monitores de Aptidão Física , Aprendizado de Máquina , Adulto , Algoritmos , Ciclismo/fisiologia , Composição Corporal , Índice de Massa Corporal , Temperatura Corporal , Calorimetria Indireta , Feminino , Resposta Galvânica da Pele , Frequência Cardíaca , Humanos , Corrida Moderada/fisiologia , Masculino , Pessoa de Meia-Idade , Comportamento Sedentário , Caminhada/fisiologia
9.
Int J Sports Med ; 41(8): 539-544, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32289842

RESUMO

The purpose was to determine the physiological correlates to cycling performance within a competitive paratriathlon. Five wheelchair user and ten ambulant paratriathletes undertook laboratory-based testing to determine their: peak rate of oxygen uptake; blood lactate- and ventilatory-derived physiological thresholds; and, their maximal aerobic power. These variables were subsequently expressed in absolute (l∙min -1 or W), relative (ml∙kg-1∙min -1 or W∙kg -1) and scaled relative (or ml∙kg - 0.82 ∙min -1, ml∙kg - 0.32 ∙min -1 or W∙kg -0.32) terms. All athletes undertook a paratriathlon race with 20 km cycle. Pearson's correlation test and linear regression analyses were produced between laboratory-derived variables and cycle performance to generate correlation coefficients (r), standard error of estimates and 95% confidence intervals. For wheelchair users, performance was most strongly correlated to relative aerobic lactate threshold (W∙kg -1) (r=-0.99; confidence intervals: -0.99 to -0.99; standard error of estimate=22 s). For ambulant paratriathletes, the greatest correlation was with maximal aerobic power (W∙kg -0.32) (r=-0.91; -0.99 to -0.69; standard error of estimate=88 s). Race-category-specificity exits regarding physiological correlates to cycling performance in a paratriathlon race with further differences between optimal scaling factors between paratriathletes. This suggests aerobic lactate threshold and maximal aerobic power are the pertinent variables to infer cycling performance for wheelchair users and ambulant paratriathletes, respectively.


Assuntos
Ciclismo/fisiologia , Comportamento Competitivo/fisiologia , Resistência Física/fisiologia , Esportes para Pessoas com Deficiência/fisiologia , Adulto , Limiar Anaeróbio/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/fisiologia
10.
Int J Sports Med ; 41(8): 545-551, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32289841

RESUMO

The aim of this study was to determine the influence of body weight or lean body mass-based load on Wingate Anaerobic Test performance in male and female endurance trained individuals. Thirty-one participants (22 male cyclists and triathletes and 9 female triathletes) completed two randomized Wingate Anaerobic Test (body weight and lean body mass loads) in stationary start. There were no significant differences in power outputs variables between loads in any group. However, when comparing specific groups within the sample (e. g. cyclists vs cyclists) medium to large effect sizes were observed for Relative Mean Power Output (ES=0.53), Relative Lowest Power (ES=0.99) and Relative Power Muscle Mass (ES=0.54). Regarding gender differences, male cyclists and triathletes displayed higher relative and absolute power outputs (p<0.001) compared to female triathletes regardless of the protocol used. FI was lower in female triathletes compared to male triathletes and cyclists in body weight (p<0.001) and lean body mass (p<0.01) protocols. Body composition and anthropometric characteristics were similar in male cyclists and triathletes, but there were differences between genders. These results suggest that using either body weight-based or lean body mass-based load can be used interchangeably. However, there may be some practically relevant differences when evaluating this on an individual level.


Assuntos
Índice de Massa Corporal , Peso Corporal , Resistência Física/fisiologia , Esportes/fisiologia , Adulto , Ciclismo/fisiologia , Estudos Cross-Over , Teste de Esforço , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Corrida/fisiologia , Fatores Sexuais , Natação/fisiologia , Adulto Jovem
11.
PLoS One ; 15(3): e0229466, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163443

RESUMO

Measurement of oxygen uptake during exercise ([Formula: see text]) is currently non-accessible to most individuals without expensive and invasive equipment. The goal of this pilot study was to estimate cycling [Formula: see text] from easy-to-obtain inputs, such as heart rate, mechanical power output, cadence and respiratory frequency. To this end, a recurrent neural network was trained from laboratory cycling data to predict [Formula: see text] values. Data were collected on 7 amateur cyclists during a graded exercise test, two arbitrary protocols (Prot-1 and -2) and an "all-out" Wingate test. In Trial-1, a neural network was trained with data from a graded exercise test, Prot-1 and Wingate, before being tested against Prot-2. In Trial-2, a neural network was trained using data from the graded exercise test, Prot-1 and 2, before being tested against the Wingate test. Two analytical models (Models 1 and 2) were used to compare the predictive performance of the neural network. Predictive performance of the neural network was high during both Trial-1 (MAE = 229(35) mlO2min-1, r = 0.94) and Trial-2 (MAE = 304(150) mlO2min-1, r = 0.89). As expected, the predictive ability of Models 1 and 2 deteriorated from Trial-1 to Trial-2. Results suggest that recurrent neural networks have the potential to predict the individual [Formula: see text] response from easy-to-obtain inputs across a wide range of cycling intensities.


Assuntos
Ciclismo/fisiologia , Exercício Físico/fisiologia , Redes Neurais de Computação , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia , Esforço Físico/fisiologia , Adulto , Feminino , Humanos , Masculino , Projetos Piloto
12.
J Sports Sci ; 38(7): 801-813, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32131692

RESUMO

Purpose: To validate and compare a novel model based on the critical power (CP) concept that describes the entire domain of maximal mean power (MMP) data from cyclists.Methods: An omni-domain power-duration (OmPD) model was derived whereby the rate of W' expenditure is bound by maximum sprint power and the power at prolonged durations declines from CP log-linearly. The three-parameter CP (3CP) and exponential (Exp) models were likewise extended with the log-linear decay function (Om3CP and OmExp). Each model bounds W' using a different nonconstant function, W'eff (effective W'). Models were fit to MMP data from nine cyclists who also completed four time-trials (TTs).Results: The OmPD and Om3CP residuals (4 ± 1%) were smaller than the OmExp residuals (6 ± 2%; P < 0.001). W'eff predicted by the OmPD model was stable between 120-1,800 s, whereas it varied for the Om3CP and OmExp models. TT prediction errors were not different between models (7 ± 5%, 8 ± 5%, 7 ± 6%; P = 0.914).Conclusion: The OmPD offers similar or superior goodness-of-fit and better theoretical properties compared to the other models, such that it best extends the CP concept to short-sprint and prolonged-endurance performance.


Assuntos
Ciclismo/fisiologia , Comportamento Competitivo/fisiologia , Modelos Estatísticos , Resistência Física/fisiologia , Adulto , Teste de Esforço , Feminino , Humanos , Masculino
13.
J Sports Sci ; 38(10): 1105-1114, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32202206

RESUMO

Prior exercise can negatively affect movement economy of a subsequent task. However, the impact of cycling exercise on the energy cost of subsequent running is difficult to ascertain, possibly because of the use of different methods of calculating economy. We examined the influence of a simulated cycling bout on running physiological cost (running economy, heart rate and ventilation rates) and perceptual responses (ratings of perceived exertion and effort) by comparing two running bouts, performed before and after cycling using different running economy calculation methods. Seventeen competitive male triathletes ran at race pace before and after a simulated Olympic-distance cycling bout. Running economy was calculated as V̇O2 (mL∙kg-1∙min-1), oxygen cost (EO2, mL∙kg-1∙m-1) and aerobic energy cost (Eaer, J∙kg-1∙m-1). All measures of running economy and perceptual responses indicated significant alterations imposed by prior cycling. Despite a good level of agreement with minimal bias between calculation methods, differences (p < 0.05) were observed between Eaer and both V̇O2 and EO2. The results confirmed that prior cycling increased physiological cost and perceptual responses in a subsequent running bout. It is recommended that Eaer be calculated as a more valid measure of running economy alongside perceptual responses to assist in the identification of individual responses in running economy following cycling.


Assuntos
Ciclismo/fisiologia , Metabolismo Energético/fisiologia , Corrida/fisiologia , Adulto , Ciclismo/psicologia , Teste de Esforço , Frequência Cardíaca/fisiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Taxa Respiratória/fisiologia , Corrida/psicologia
14.
Int J Sports Physiol Perform ; 15(5): 639-647, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32023545

RESUMO

PURPOSE: To examine the effects of daily cold- and hot-water recovery on training load (TL) during 5 days of heat-based training. METHODS: Eight men completed 5 days of cycle training for 60 minutes (50% peak power output) in 4 different conditions in a block counter-balanced-order design. Three conditions were completed in the heat (35°C) and 1 in a thermoneutral environment (24°C; CON). Each day after cycling, participants completed 20 minutes of seated rest (CON and heat training [HT]) or cold- (14°C; HTCWI) or hot-water (39°C; HTHWI) immersion. Heart rate, rectal temperature, and rating of perceived exertion (RPE) were collected during cycling. Session-RPE was collected 10 minutes after recovery for the determination of session-RPE TL. Data were analyzed using hierarchical regression in a Bayesian framework; Cohen d was calculated, and for session-RPE TL, the probability that d > 0.5 was also computed. RESULTS: There was evidence that session-RPE TL was increased in HTCWI (d = 2.90) and HTHWI (d = 2.38) compared with HT. The probabilities that d > 0.5 were .99 and .96, respectively. The higher session-RPE TL observed in HTCWI coincided with a greater cardiovascular (d = 2.29) and thermoregulatory (d = 2.68) response during cycling than in HT. This result was not observed for HTHWI. CONCLUSION: These findings suggest that cold-water recovery may negatively affect TL during 5 days of heat-based training, hot-water recovery could increase session-RPE TL, and the session-RPE method can detect environmental temperature-mediated increases in TL in the context of this study.


Assuntos
Ciclismo/fisiologia , Temperatura Baixa , Temperatura Alta , Imersão , Condicionamento Físico Humano/métodos , Adulto , Teorema de Bayes , Regulação da Temperatura Corporal , Teste de Esforço , Frequência Cardíaca/fisiologia , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Água , Adulto Jovem
15.
Am J Physiol Endocrinol Metab ; 318(4): E504-E513, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32069071

RESUMO

We hypothesized that probiotic supplementation (PRO) increases the absorption and oxidation of orally ingested maltodextrin during 2 h endurance cycling, thereby sparing muscle glycogen for a subsequent time trial (simulating a road race). Measurements were made of lipid and carbohydrate oxidation, plasma metabolites and insulin, gastrointestinal (GI) permeability, and subjective symptoms of discomfort. Seven male cyclists were randomized to PRO (bacterial composition given in methods) or placebo for 4 wk, separated by a 14-day washout period. After each period, cyclists consumed a 10% maltodextrin solution (initial 8 mL/kg bolus and 2 mL/kg every 15 min) while exercising for 2 h at 55% maximal aerobic power output, followed by a 100-kJ time trial. PRO resulted in small increases in peak oxidation rates of the ingested maltodextrin (0.84 ± 0.10 vs. 0.77 ± 0.09 g/min; P = 0.016) and mean total carbohydrate oxidation (2.20 ± 0.25 vs. 1.87 ± 0.39 g/min; P = 0.038), whereas fat oxidation was reduced (0.40 ± 0.11 vs. 0.55 ± 0.10 g/min; P = 0.021). During PRO, small but significant increases were seen in glucose absorption, plasma glucose, and insulin concentration and decreases in nonesterified fatty acid and glycerol. Differences between markers of GI damage and permeability and time-trial performance were not significant (P > 0.05). In contrast to the hypothesis, PRO led to minimal increases in absorption and oxidation of the ingested maltodextrin and small reductions in fat oxidation, whereas having no effect on subsequent time-trial performance.


Assuntos
Ciclismo/fisiologia , Metabolismo dos Carboidratos/efeitos dos fármacos , Suplementos Nutricionais , Probióticos/farmacologia , Adulto , Estudos Cross-Over , Carboidratos da Dieta , Método Duplo-Cego , Exercício Físico , Ácidos Graxos não Esterificados/sangue , Glucose/metabolismo , Glicerol/sangue , Humanos , Insulina/sangue , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Polissacarídeos/farmacocinética , Adulto Jovem
16.
PLoS One ; 15(2): e0228491, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32032390

RESUMO

Latin Americans engage in physical activity (PA) in unique ways and use a wider range of places for PA than those commonly studied in high-income settings. We examined the contribution of a variety of places and domains of PA to meeting PA recommendations among a sample of adults (18-65 y) from all over Mexico. This was a cross-sectional study conducted in 2017 (n = 3 686). Overall and domain-specific PA was measured using the Global Physical Activity Questionnaire. Use of places for PA was self-reported. Places were classified as private or public. In 2018, associations between specific places and meeting PA recommendations (≥150 mins/week) were estimated using multivariate logistic regression models. In total 72.1% met PA recommendations. The proportion meeting recommendations through domain-specific PA was highest for leisure-time PA (50.0%), followed by travel-related (39.1%) and work-related (24.9%) PA. The most commonly reported places for PA were home (43%), parks (40.7%) and streets (39.4%) (public). Use of most public places was positively associated with meeting PA recommendations, mainly through travel-related PA (Streets OR 2.05 [95% CI 1.71-2.45]; Cycling paths OR 1.91 [1.37-2.68]). Using private places was more strongly associated with PA, mainly leisure-time PA (Gyms OR 9.66 [7.34-12.70]); Sports facilities OR 5.03 [3.27-7.74]). In conclusion, public and private places were important contributors to PA. While public places may be a powerful setting for PA promotion, increasing the equitable access for all to private places may also represent an effective strategy to increase PA among Mexican adults.


Assuntos
Planejamento Ambiental , Exercício Físico/fisiologia , Atividades de Lazer , Características de Residência , Adolescente , Adulto , Idoso , Ciclismo/fisiologia , Estudos Transversais , Feminino , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Parques Recreativos/estatística & dados numéricos , Instalações Privadas/estatística & dados numéricos , Logradouros Públicos/estatística & dados numéricos , Características de Residência/estatística & dados numéricos , Fatores Socioeconômicos , Inquéritos e Questionários , Adulto Jovem
17.
Artigo em Inglês | MEDLINE | ID: mdl-32041164

RESUMO

Background: Knowledge of acute responses to different sprint interval exercise (SIE) helps to implement new training programs. The aim of this study was to compare the acute physiological, metabolic and perceptual responses to two different SIE cycling protocols with different recovery durations. Methods: Twelve healthy, active male participants took part in this study and completed four testing sessions in the laboratory separated by a minimum of 72h. Two SIE protocols were applied in randomized order: SIE6×10"/4'-six "all-out" repeated 10-s bouts, interspersed with 4-min recovery; and SIESERIES-two series of three "all-out" repeated 10-s bouts, separated by 30-s recovery and 18-min recovery between series. Protocols were matched for the total work time (1 min) and recovery (20 min). Results: In SIESERIES, peak oxygen uptake and peak heart rate were significantly higher (p < 0.05), without differences in peak blood lactate concentration and mean rating of perceived exertion compared to SIE6×10"/4'. There were no differences in peak power output, peak oxygen uptake and peak heart rate between both series in SIESERIES. Conclusions: Two series composed of three 10-s "all-out" bouts in SIESERIES protocol evoked higher cardiorespiratory responses, which can provide higher stimulus to improve aerobic fitness in regular training.


Assuntos
Ciclismo/fisiologia , Treinamento Intervalado de Alta Intensidade , Adulto , Frequência Cardíaca , Humanos , Masculino , Consumo de Oxigênio , Adulto Jovem
18.
Int J Sports Med ; 41(3): 175-181, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31952081

RESUMO

Functional threshold power (FTP) is defined as the highest power that a cyclist can maintain in a quasi-steady state without fatigue for approximately 1 hour. To improve practicality, a 20-minute time-trial test was proposed, where FTP is represented by 95% of the mean power produced. It is preceded by a specific 45-min warm-up, with periods of low intensity, fast accelerations, and a 5-min time-trial. Thus, the aim of this study was to determine the reliability of this protocol, including the reliability of the warm-up, pacing strategy, and FTP determination. For this purpose, 25 trained cyclists performed a familiarization and two other tests separated by seven days. The coefficient of variation (CV [%]), intraclass correlation coefficient (ICC), and change in the mean between test and retest were calculated. The results show that the 20-min time-trial was reliable (CV=2.9%, ICC=0.97), despite a less reliable warm-up (CV=5.5%, ICC=0.84). The changes in the mean between the test and retest were trivial to small for all measurements, and the pacing strategy was consistent across all trials. These results suggest that FTP determination with a 20-min protocol was reliable in trained cyclists.


Assuntos
Limiar Anaeróbio/fisiologia , Ciclismo/fisiologia , Comportamento Competitivo/fisiologia , Teste de Esforço/métodos , Adulto , Humanos , Masculino , Consumo de Oxigênio , Reprodutibilidade dos Testes , Exercício de Aquecimento/fisiologia
19.
Int J Sports Physiol Perform ; 15(5): 741-747, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31952047

RESUMO

BACKGROUND: Gross efficiency (GE) declines during high-intensity exercise. Increasing extracellular buffer capacity might diminish the decline in GE and thereby improve performance. PURPOSE: To examine if sodium bicarbonate (NaHCO3) supplementation diminishes the decline in GE during a 2000-m cycling time trial. METHODS: Sixteen male cyclists and 16 female cyclists completed 4 testing sessions including a maximal incremental test, a familiarization trial, and two 2000-m GE tests. The 2000-m GE tests were performed after ingestion of either NaHCO3 supplements (0.3 g/kg body mass) or placebo supplements (amylum solani, magnesium stearate, and sunflower oil capsules). The GE tests were conducted using a double-blind, randomized, crossover design. Power output, gas exchange, and time to complete the 2000-m time trials were recorded. Capillary blood samples were analyzed for blood bicarbonate, pH, and lactate concentration. Data were analyzed using magnitude-based inference. RESULTS: The decrement in GE found after the 2000-m time trial was possibly smaller in the male and female groups after NaHCO3 than with placebo ingestion, with the effect in both groups combined being unclear. The effect on performance was likely trivial for males (placebo 164.2 [5.0] s, NaHCO3 164.3 [5.0] s; Δ0.1; ±0.6%), unclear for females (placebo 178.6 [4.8] s, NaHCO3 178.0 [4.3] s; Δ-0.3; ±0.5%), and very likely trivial when effects were combined. Blood bicarbonate, pH, and lactate concentration were substantially elevated from rest to pretest after NaHCO3 ingestion. CONCLUSIONS: NaHCO3 supplementation results in an unclear effect on the decrease in GE during high-intensity exercise and in a very likely trivial effect on performance.


Assuntos
Ciclismo/fisiologia , Suplementos Nutricionais , Resistência Física/fisiologia , Bicarbonato de Sódio/administração & dosagem , Adulto , Método Duplo-Cego , Feminino , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/sangue , Masculino , Troca Gasosa Pulmonar , Bicarbonato de Sódio/sangue
20.
Int J Sports Physiol Perform ; 15(5): 759-762, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32000141

RESUMO

PURPOSE: Due to age-related changes in the psychobiological state of masters athletes, this brief report aimed to compare training load responses using heart rate (HR) and ratings of perceived exertion (RPE) during standardized training sessions between masters and young cyclists. METHODS: Masters (n = 10; 55.6 [5.0] y) and young (n = 8; 25.9 [3.0] y) cyclists performed separate endurance and high-intensity interval training sessions. Endurance intensity was set at 95% of ventilatory threshold 2 for 1 hour. High-intensity interval training consisted of 6 × 30-second intervals at 175% peak power output with 4.5-minute rest between intervals. HR was monitored continuously and RPE collected at standardized time periods during each session. Banister training impulse and summated-HR-zones training loads were also calculated. RESULTS: Despite a significantly lower mean HR in masters cyclists during endurance (P = .04; d = 1.06 [±0.8], moderate) and high-intensity interval training (P = .01; d = 1.34 [±0.8], large), no significant differences were noted (P > .05) when responses were determined relative to maximum HR or converted to training impulse and summated-HR-zone loads. Furthermore, no interaction or between-group differences were evident for RPE across either session (P > .05). CONCLUSIONS: HR and RPE values were comparable between masters and young cyclists when relative HR responses and HR training load models are used. This finding suggests HR and RPE methods used to monitor or prescribe training load can be used interchangeably between masters and young athletes irrespective of chronological age.


Assuntos
Envelhecimento/fisiologia , Ciclismo/fisiologia , Frequência Cardíaca , Treinamento Intervalado de Alta Intensidade/métodos , Percepção/fisiologia , Esforço Físico/fisiologia , Adulto , Humanos , Pessoa de Meia-Idade
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