Influence of physical fitness and weight status on autonomic cardiac modulation in children.

BACKGROUND: This study provides reference values for cardiovascular modulation at rest, during maximal exercise test and recovery after exercise in Caucasian children according to weight status and cardiorespiratory fitness (CRF) level. Additionally, the current study analyzed several correlations between autonomic cardiovascular modulation, cardiorespiratory performance and cardiometabolic risk. The principal goal of this study was to analyze cardiac function at rest, during maximum exercise, and during the recovery phase in children grouped according to weight status and CRF level. METHODS: One hundred and fifty-two healthy children (78 girls) 10-16 years of age were divided into three groups: soccer and basketball players (SBG), endurance group (EG), and sedentary people with overweight and obesity (OOG). A cardiac RR interval monitor recorded the cardiac data and specific software analyzed the cardiac autonomic response through heart rate (HR) and HR variability. The study analyzed resting HR (RHR), HRpeak, and HR recovery (HRR). RESULTS: OOG showed significant poorer performance in the Léger test lower V̇O2 max and higher values of blood pressure at rest and post-exercise than sport groups. The EG presented the best results in CRF and cardiometabolic risk (CMR) in relation to SBG and OOG. The OOG showed higher percentage of HR values, compatible with an unhealthy cardiovascular autonomic modulation than the sport groups, with significant differences in bradycardia, HR reserve, and HRR 5 min. CONCLUSIONS: Aerobic performance, vagal activity, blood pressure, chronotropic competence, and HRR have significant associations with CMR parameters. IMPACT: The current study presents reference values of autonomic cardiac function in Caucasian children according to weight status and cardiorespiratory fitness level. Aerobic performance, vagal activity, blood pressure, chronotropic competence, and heart rate during the recovery period after exercise have significant associations with cardiometabolic risk parameters. Children with overweight and obesity show signs of autonomic dysfunction reflected as low cardiac vagal activity and poor chronotropic competence.

Reference Values of Spatial and Temporal Gait Parameters in a Contemporary Sample of Spanish Preschool Children: A Cross-Sectional Study.

The aim of this study was to analyze the influence of age and sex on kinematic gait parameters in preschool children, and derive reference values for this population. A total of 383 preschool children (age 3-5 years; 207 girls, 176 boys) participated in this study. We used the OptoGait system to assess the kinematics of gait at a comfortable and self-determined speed. No significant differences between the sexes were found for the main gait parameters. Among the participants, there was a significant increase in double support, reductions in absolute cadence and the coefficient of variation (CV) of cadence, an increase in absolute step length (SL), and an increase in the walk ratio (WR) from 3 to 5 years of age. However, the normalized SL and normalized WR displayed a significant reduction in both sexes. Partial correlation indicated a significant association of age with SL and normalized SL, and WR. Additionally, WR showed a significant correlation with the CV of cadence. To summarize, no relevant differences in gait performance were found according to sex; however, age was found to influence gait maturation. The normative values established for Spanish preschool children can be used to monitor healthy gait development.

Is the Xiaomi Mi Band 4 an Accuracy Tool for Measuring Health-Related Parameters in Adults and Older People? An Original Validation Study.

BACKGROUND: The aim of this study was to analyse the validity and accuracy of the low-cost Xiaomi Mi Band 4 (MB4) fitness tracker in relation to step count and heart rate in free-living conditions. METHODS: 46 participants join in this study (38.65 ± 14.36 years old). The MB4 was compared with a video recording in laboratory conditions, also with the Sense Wear and Firstbeat monitors in free-living conditions. RESULTS: No significant differences were found in the number of steps in the laboratory protocol between devices, in both, at low and high walking speed. For the free-living conditions, the MB4 showed high values of convergent validity in relation to the Firstbeat monitor during recording in both rest and walking situations. Moreover, the MB4 showed adequate values of convergent validity with the Sense Wear monitor during the 24 h recording, at medium speeds, and climbing stairs. CONCLUSION: The accuracy and precision of the MB4 is reasonable and can be used to monitor the average of step count and heart rate in free-living conditions.

Complex Gait Is Related to Cognitive Functioning in Older People: A Cross-Sectional Study Providing an Innovative Test.

BACKGROUND: Many studies have demonstrated an inverse relationship between gait performance and cognitive impairment. The main purposes of this study were: (1) to design and validate a complex gait test (CGT) in older people, (2) to analyze the effects of age and sex on CGT, and (3) to analyze the association between CGT performance and physical functioning and cognitive measures. METHODS: A total of 279 older people (60-97 years) were analyzed in 2019. Fitness tests, gait performance, and several cognitive measures such asthe Trail-Walking Test and Montreal Cognitive Assessment were used. RESULTS: The CGT reported adequate reliability and validity parameters. In the test-retest analysis, the intra-class correlation coefficient was 0.868 (p < 0.001). There was a significant correlation between the CGT and Trail-Walking Test (r = 0.592; p < 0.001). The linear regression analysis showed that the CGT was associated with the Montreal Cognitive Assessment (R2 = 0.357; p =0.001). The binary logistic regression analysis revealed that a high CGT score was a risk factor for mild cognitive impairment (odds ratio 1.201, 95% CI 1.081-1.334; p = 0.001). The ROC curve of the mild cognitive impairment was predicted by the CGT performance (area under the curve = 0.768, 95% CI 0.647-0.889; p < 0.001), reaching the cut-off point at 20.25 s. CONCLUSIONS: The CGT showed good reliability and validity and may serve as a potential biomarker in mild cognitive impairment prediction in older adults aged 60-97 years.

Effects of 12 weeks of barefoot running on foot strike patterns, inversion-eversion and foot rotation in long-distance runners.

PURPOSE: The purpose of this study was to determine the effects of 12 weeks of barefoot running on foot strike patterns, inversion-eversion and foot rotation in long-distance runners. METHODS: Thirty-one endurance runners with no experience in barefoot running were randomized into a control group and an experimental group who received barefoot training. At pre-test and post-test, all subjects ran at low and high self-selected speeds on a treadmill. Data were collected by systematic observation of lateral and back recordings at 240 Hz. RESULTS: McNemar's test indicated significant changes (p < 0.05) in the experimental group at both high and low speed running in foot strike patterns, reducing the percentage of high rearfoot strikers and increasing the number of midfoot strikers. A significant increase (p < 0.05) of external rotation of the foot and a decrease of inversion occurred at comfortable speed in the experimental group. CONCLUSION: Twelve weeks of barefoot running, applied progressively, causes significant changes in foot strike pattern with a tendency toward midfoot or forefoot strikes, regardless of running speed and significant changes in foot rotation at low speed, while the inversion was reduced in left foot at low speed with a tendency toward centered strike.

Effects of 12-Week Concurrent High-Intensity Interval Strength and Endurance Training Program on Physical Performance in Healthy Older People.

García-Pinillos, F, Laredo-Aguilera, JA, Muñoz-Jiménez, M, and Latorre-Román, PA. Effects of 12-week concurrent high-intensity interval strength and endurance training program on physical performance in healthy older people. J Strength Cond Res 33(5): 1445-1452, 2019-This study aimed to analyze the effect of 12-week low-volume high-intensity interval training (HIIT)-based concurrent training program on body composition, upper- and lower-body muscle strength, mobility, and balance in older adults, as well as to compare it with a low-moderate-intensity continuous training. Ninety active older adults were randomly assigned to experimental group (EG, n = 47) and control group (CG, n = 43). Body composition and physical functioning were assessed before (pretest) and after (posttest) a 12-week intervention. A 2-way repeated measures analysis of variance was used to test for an interaction between training program and groups. The time × group interaction revealed no significant between-group differences at pretest (p ≥ 0.05). The group × time interaction showed significant improvements for the EG in body composition parameters (p ≤ 0.05) and physical functioning (muscle strength: p < 0.001; mobility: p < 0.001; and balance: p ≤ 0.05); whereas the CG remained unchanged (p ≥ 0.05). This HIIT-based concurrent training program led to greater improvements in body composition, muscle strength, mobility, and balance in healthy older people than a regular low-moderate-intensity continuous training, despite the reduction in overall training volume.

¿Puede modificarse la cinética de la carrera mediante un programa de entrenamiento descalcista? / Can running kinetics be modified using a barefoot training program?

Introducción: Existe información limitada acerca de los programas de transición a carrera descalza, y este estudio ayudará a incrementar el conocimiento acerca de esta tendencia creciente. Por tanto, el objetivo de este estudio fue determinar el efecto de un programa de entrenamiento descalcista de 12 semanas sobre las variables cinéticas en los corredores de larga distancia. Materiales y métodos: Un total de 32 corredores de larga distancia, bien entrenados, y habitualmente calzados, fueron distribuidos aleatoriamente en un grupo experimental para llevar a cabo un programa de entrenamiento descalcista. Durante las pruebas previas y posteriores, todos los participantes realizaron las pruebas a velocidades de carrera de recuperación y competitiva auto-seleccionadas, utilizando sus zapatillas deportivas en una cinta ergométrica. Ambas situaciones se registraron con un sistema de calificación por vídeo de 240Hz, y se analizaron mediante un programa de edición de vídeo 2D con técnicas fotogramétricas. Se midieron el tiempo de contacto, la duración del paso y la cadencia mediante análisis de la varianza (ANOVA) con mediciones repetidas. Resultados: En la prueba posterior, solo la duración de la fase de aterrizaje a alta velocidad reflejó una diferencia significativa, logrando el grupo experimental un tiempo inferior que el grupo control tras el programa de entrenamiento descalcista (0,032±0,007s frente a 0,038±0,006s). Con relación a las diferencias entre grupos, el grupo control reflejó un incremento en la duración de la fase de apoyo a baja velocidad (Δ=0,014s; p=0,024) y una reducción del tiempo de vuelo a alta velocidad (Δ=−0,014s; p=0,034). Además, el grupo experimental logró una reducción de la duración de la fase de aterrizaje a alta velocidad (Δ=−0,008s; p=0,004). Conclusiones: Un programa de carrera descalcista de 12 semanas modifica la duración de la fase de aterrizaje a alta velocidad, que es más corta en los corredores de larga distancia. Por contra, los corredores que no realizaron el entrenamiento reflejaron un incremento de la duración de la fase de apoyo a baja velocidad

Introduction: There is limited information about barefoot transition programs and this study will help to increase knowledge about this growing trend. The purpose of this study was, therefore, to determine the effect of a twelve-week barefoot training program on kinematic variables in long-distance runners. Materials and methods: A total of 32 well-trained, habitually shod, long-distance runners, randomized in a control group and an experimental group who undertook a barefoot training program. At pre-test and post-test, all participants, wearing their usual sneakers, performed running tests at self-selected recovery and competitive running speeds on a treadmill. Both conditions were recorded with a 240Hz video rate system and analyzed using a 2-D video editing program using photogrammetric techniques. Contact time, flight time, step duration and cadence were measured using an analysis of variance (ANOVA) with repeated measures was performed. Results: In posttest, only the duration of landing phase at high speed showed significant difference, the experimental group achieved a shorter time than the control group after the barefoot training program (0.032±0.007s vs. 0.038±0.006s). In relation to within-group differences, the control group showed an increase of duration of stance phase at low speed (Δ=0.014s, p=0.024) and a reduction of flight time at high speed (Δ=−0.014s, p=0.034). Moreover, the experimental group achieved a reduction of duration of landing phase at high speed (Δ=−0.008s, p=0.004). Conclusions: A twelve-week program of barefoot running changes the duration of the landing phase at high speed, being shorter in long-distance runners. In contrast, the runners who did not undertake the training showed an increase of duration of stance phase at low speed

Efectos agudos de la carrera sin zapatillas y sus requisitos en la cinemática de las extremidades inferiores en corredores resistentes habitualmente calzados / Acute effects of barefoot running and running requirement on lower-limb kinematics in habitually shod endurance runners

El objetivo de este estudio fue analizar las variables cinemáticas en la carrera sin zapatillas y utilizando zapatillas convencionales específicas para carrera, a nivel de velocidad confortable y exigente. Los participantes fueron 60 corredores recreativos sanos (edad, 35,6 ± 11,7 años, índice de masa corporal, 22,9 ± 2,4 kg/m2), quienes realizaron las pruebas descalzos sobre una cinta a velocidades confortable y exigente, seleccionadas por ellos mismos. Se utilizaron técnicas fotogramétricas (2D). En la carrera sin zapatillas, el tiempo de contacto fue menor (p < 0,001) a velocidad exigente, el tiempo de vuelo fue más corto a velocidades confortable (p < 0,05) y exigente (p < 0,05), y la frecuencia de la zancada fue superior en ambas velocidades (p < 0,001). Además, en la carrera sin zapatillas los corredores aterrizaron con una flexión de rodillas considerablemente superior (p < 0,05), menor dorsiflexión de tobillos (p < 0,001) y menor flexión de rodillas en el despegue, a velocidad exigente (p = 0,002) en la carrera con zapatillas. En conclusión, el presente estudio ha aportado una evidencia que sugiere que se producen cambios agudos en las variables temporales y cinemáticas en la carrera con/sin zapatillas a baja y alta velocidad, en los corredores que utilizan normalmente zapatillas. Se hallaron diferencias significativas en cuanto a sucesos espaciotemporales en carrera sin zapatillas, con una mayor flexión de rodillas y dorsiflexión de tobillos. Al aumentar la velocidad al correr descalzos, la duración de las variables de tiempo disminuyó considerablemente tanto en velocidad confortable como en exigente (p < 0,001). Debido a ello, el ciclo de zancada y de marcha fue considerablemente más rápido y, por tanto, se produjo una mayor frecuencia de zancada (AU)

The aim of this study was to analyse kinematic variables when running barefoot and when wearing conventional running shoes at comfortable and demanding running speeds. Sixty healthy recreational male runners (age = 35.6 ± 11.7 years old, body mass index = 22.9 ± 2.4 kg/m 2 ) performed trials in shod/barefoot running conditions on a treadmill At self-selected comfortable and demanding speeds. Photogrammetric techniques (2D) were employed. In barefoot conditions, contact time was shorter (p < 0.001) at demanding speed, flight time was shorter at comfortable (p < 0.05) and demanding (p < 0.05) speeds, and there was greater stride frequency at both speeds (p < 0.001). In addition, in barefoot conditions, runners landed with significantly greater knee flexion (p < 0.05); lower ankle dorsiflexion (p < 0.001); and lower knee flexion in take-off at demanding speed (p = 0.002) compared with shod conditions. In conclusion, the current study has provided evidence to suggest that acute changes occur in the temporal variables and kinematics between shod/barefoot conditions at low and high speeds in habitually shod runners. Significant differences were found in spatial- - -temporal events between shod/barefoot conditions, with shorter times in barefoot conditions with greater knee flexion and ankle dorsiflexion. When speed was increased in barefoot conditions, duration of timing variables decreased significantly both comfortable and demanding speed (p < 0.001). Because of this, stride and gait cycle was significantly faster and thus there was a higher stride frequency (AU)

Physiological and Neuromuscular Response to a Simulated Sprint-Distance Triathlon: Effect of Age Differences and Ability Level.

This study aimed to describe the acute impact of a simulated sprint-distance triathlon at physiological and neuromuscular levels and to determine whether age and athletic performance influenced the response in triathletes. Nineteen triathletes performed a sprint-distance triathlon under simulated conditions. Cardiovascular response was monitored during the race. Rate of perceived exertion along with muscular performance parameters (countermovement jump [CMJ], squat jump [SJ], and handgrip strength test [HS]) were tested at pre- and posttest and during every transition, while a 20-m sprint test (S20m) was performed before and after the race. Blood lactate was recorded postrace. A repeated measures analysis of variance showed that the neuromuscular response-in terms of CMJ, SJ, and HS-was unchanged (p ≥ 0.05), while S20m performance was impaired at posttest (p < 0.001). A linear regression analysis showed that ΔCMJ predicted the overall race time (R = 0.226; p = 0.046). In addition, 2 cluster analyses (k-means) were performed by grouping according to athletic performance and age. Between-group comparison showed no significant differences in the impact of the race at either the physiological or the neuromuscular level. The results showed that muscular performance parameters were not impaired throughout the race despite high levels of fatigue reported. However, despite maintaining initial levels of muscle force after the race, the fatigue-induced changes in S20m were significant, which could reinforce the need to train sprint ability in endurance athletes. Finally, despite the differences in ability level or in age, the acute physiological and neuromuscular responses to a simulated sprint-distance triathlon were similar.

Gait speed in older people: an easy test for detecting cognitive impairment, functional independence, and health state.

BACKGROUND: With ageing, physical and cognitive functions become impaired. Analyzing and determining the association between both functions can facilitate the prevention and diagnosis of associated problems. Some previous works have proposed batteries of physical performance tests to determine both physical and cognitive functions. However, only a few studies have used the gait speed (GS) test as a tool to evaluate parameters representative of health in the elderly such as functionality, mobility, independence, autonomy, and comorbidity. Therefore, the aim of this study was to determine the association between physical and cognitive functions in older people (over 65 years old) and to detect the most appropriate physical test to assess cognitive impairment, functional independence, comorbidity, and perceived health in this population. METHODS: One hundred six older adults (38 men, 68 women) participated voluntarily in this cross-sectional study. To assess the physical function handgrip strength, GS, 30-s chair stand tests, and body composition analysis were performed. To evaluate cognitive function, the Mini-Mental State Examination, Barthel index, and Charlson index were employed. No significant differences (P ≥ 0.05) between sexes were found. RESULTS: Multiple regression analysis of the Mini-Mental State Examination and physical fitness variables, adjusted for age and sex, indicates that GS is a predictor of Mini-Mental State Examination score (R(2) = 0.138). CONCLUSION: The results showed that GS is an important predictor of functional capacity (physical and cognitive function) in adults over 65 years old.