Increasing cadence with a metronome and running barefoot changes the sagittal kinematics of the lower limbs and trunk.

The purpose was to compare two non-laboratory based running retraining programs on lower limb and trunk kinematics in recreational runners. Seventy recreational runners (30 ± 7.3 years old, 40% female) were randomised to a barefoot running group (BAR), a group wearing a digital metronome with their basal cadence increased by 10% (CAD), and a control group (CON). BAR and CAD groups included intervals from 15 to 40 min over 10 weeks and 3 days/week. 3D sagittal kinematics of the ankle, knee, hip, pelvis, and trunk were measured before and after the retraining program, at comfortable and high speeds. A 3 × 2 mixed ANOVA revealed that BAR and CAD groups increased knee and hip flexion at footstrike, increased peak hip flexion during stance and flight phase, decreased peak hip extension during flight phase, and increased anterior pelvic tilt at both speeds after retraining. In addition, BAR increased ankle plantar flexion at footstrike and increased anterior trunk tilt. Both retraining programs demonstrated significant moderate to large effect size changes in parameters that could reduce the mechanical risks of injury associated with excessive knee stress, which is of interest to coaches, runners and those prescribing rehabilitation and injury prevention programs.

The effect of two retraining programs, barefoot running vs increasing cadence, on kinematic parameters: A randomized controlled trial.

The aim of this study was to compare the effects of two 10-week non-laboratory-based running retraining programs on foot kinematics and spatiotemporal parameters in recreational runners. One hundred and three recreational runners (30 ± 7.2 years old, 39% females) were randomly assigned to either: a barefoot retraining group (BAR) with 3 sessions/week over 10 weeks, a cadence retraining group (CAD) who increased cadence by 10% again with 3 sessions/week over 10 weeks and a control group (CON) who did not perform any retraining. The footstrike pattern, footstrike angle (FSA), and spatial-temporal variables at comfortable and high speeds were measured using 2D/3D photogrammetry and a floor-based photocell system. A 3 × 2 ANOVA was used to compare between the groups and 2 time points. The FSA significantly reduced at the comfortable speed by 5.81° for BAR (p < 0.001; Cohen's d = 0.749) and 4.81° for CAD (p = 0.002; Cohen's d = 0.638), and at high speed by 6.54° for BAR (p < 0.001; Cohen's d = 0.753) and by 4.71° for CAD (p = 0.001; Cohen's d = 0.623). The cadence significantly increased by 2% in the CAD group (p = 0.015; Cohen's d = 0.344) at comfortable speed and the BAR group showed a 1.7% increase at high speed. BAR and CAD retraining programs showed a moderate effect for reducing FSA and rearfoot prevalence, and a small effect for increasing cadence. Both offer low-cost and feasible tools for gait modification within recreational runners in clinical scenarios.

Exercise-Based Training Strategies to Reduce the Incidence or Mitigate the Risk Factors of Anterior Cruciate Ligament Injury in Adult Football (Soccer) Players: A Systematic Review.

Anterior cruciate ligament (ACL) is one of the most concerning injuries for football players. The aim of this review is to investigate the effects of exercise-based interventions targeting at reducing ACL injury rate or mitigating risk factors of ACL injury in adult football players. Following PRISMA guidelines, a systematic search was conducted in CINAHL, Cochrane Library, PubMed, Scopus, SPORTDiscus and Web of Science. Studies assessing the effect of exercise-based interventions in ACL injury incidence or modifiable risk factors in adult football players were included. 29 studies evaluating 4502 male and 1589 female players were included (15 RCT, 8 NRCT, 6 single-arm): 14 included warm-up, 7 resistance training, 4 mixed training, 3 balance, 1 core stability and 1 technique modification interventions. 6 out of 29 studies investigated the effect of interventions on ACL injury incidence, while the remaining 23 investigated their effect on risk factors. Only 21% and 13% studies evaluating risk of injury variables reported reliability measures and/or smallest worthwhile change data. Warm-up, core stability, balance and technique modification appear effective and feasible interventions to be included in football teams. However, the use of more ecologically valid tests and individually tailored interventions targeting specific ACL injury mechanisms are required.

Analysis of foot strike pattern, rearfoot dynamic and foot rotation over childhood. A cross-sectional study.

The purpose of this study was to determine the foot strike patterns (FSP), rearfoot position at initial contact (RPic, i.e., No INV/EVE) and foot rotation in children in relation to age. A total of 932 children aged 3 to 16 years participated in this study. A sagittal and frontal-plane video was recorded using a high-speed camcorder to analyse these variables. There is a significant increase (p < 0.001) of rearfoot strike patterns (RFS) prevalence in relation to age; e.g. preschool children (3-6 years old) displayed an RFS prevalence 46.65% and the adolescent population(15-16 years old) an RFS prevalence 92.20%. The total RFS prevalence in all samples was 69.25%. There was a significant reduction (p < 0.001) of prevalence of RPic in relation to age groups; preschool children displayed a prevalence of RPic 60.37% and the adolescent population 10%. There was a significant reduction (p < 0.001) of prevalence of no foot rotation in relation to age groups; preschool children displayed a prevalence of no foot rotation 48.95% and the adolescent population 13.55%. In conclusion, FSP in children are influenced by age. It is noteworthy that the RFS prevalence of children is lower in comparison to the adult population.

DIFERENCIAS ESPACIO-TEMPORALES DE LA LOCOMOCIÓN EN ADULTOS VARONES CON NORMOPESO Y SOBREPESO / DIFERENÇAS ESPAÇO-TEMPORAIS NA LOCOMOÇÃO DE ADULTOS DO SEXO MASCULINO COM PESO NORMAL E SOBREPESO / SPATIO-TEMPORAL DIFFERENCES OF LOCOMOTION OF ADULT MALES WITH NORMAL WEIGHT AND OVERWEIGHT

RESUMEN Introducción: La obesidad ha estado relacionada con la presencia de adaptaciones estructurales y funcionales que provocan limitaciones en el control del movimiento. Objetivo: Determinar el efecto del exceso de peso sobre las variables espacio-temporales de la locomoción en varones jóvenes y activos. Métodos: Estudio de corte transversal de muestreo no probabilístico con 55 sujetos con normopeso (IMC ≤25) y 22 sujetos con sobrepeso (IMC >25). Se analizó el IMC, % de masa grasa, y el % de masa magra de ambos grupos con un bioimpedanciómetro multifrecuencia (Inbody 230). También se analizaron las variables cinemáticas de la locomoción utilizando una plataforma de presiones GaitRite. Resultados: El grupo con sobrepeso mostró una disminución significativa de la fase de oscilación y fase de apoyo monopodal (p <0,001) junto con un aumento de la fase de apoyo y fase de apoyo bipodal (p <0,001) comparado con el grupo normopeso. Conclusión: La reducción de la fase de oscilación y el incremento de la fase de apoyo y fase de apoyo bipodal que manifestaron el grupo con sobrepeso puede ser consecuencia del aumento de la inestabilidad que se produce durante la marcha debido al sobrepeso.

RESUMO Introdução: A obesidade tem sido relacionada com a presença de adaptações estruturais e funcionais que podem limitar o controle dos movimentos. Objetivo: Determinar o efeito do excesso de peso sobre as variáveis espaço-temporais da locomoção em homens jovens e ativos. Métodos: Estudo transversal de amostragem não probabilística, com 55 indivíduos com peso normal (IMC ≤25) e 22 indivíduos com sobrepeso (IMC >25). Analisaram-se IMC e porcentagem de massa gorda e massa magra em ambos os grupos, com um bioimpedanciômetro multifrequência (Inbody 230). Foram analisadas também as variáveis cinemáticas de locomoção, usando-se um sistema de plataforma de pressão (GaitRite). Resultados: O grupo sobrepeso apresentou diminuição significativa na fase de balanço e fase de apoio monopodal (p <0,001), com aumento da fase de apoio e da fase de apoio bipodal (p <0,001) com relação ao grupo peso normal. Conclusão: A redução da fase de balanço e o aumento da fase de apoio e da fase de apoio bipodal manifestado pelo grupo sobrepeso pode ser resultado do aumento da instabilidade que ocorre durante a marcha, devido ao sobrepeso.

ABSTRACT Introduction: Obesity has been associated with the presence of structural and functional adaptations that may limit movement control. Objective: To determine the effect of overweight on spatio-temporal variables of locomotion in young and active men. Methods: A cross-sectional study of non-probability sampling, with 55 subjects with normal weight (BMI ≤25) and 22 overweight subjects (BMI >25). Body mass index and percentage of fat mass and lean mass were analyzed in both groups, with a multi-frequency bioimpedanciometer (Inbody 230). The kinematic variables of locomotion were also analyzed with a pressure platform system (GaitRite). Results: The overweight group showed a significant decrease in the swing phase and monopodal stance phase (p <0.001) with an increase in the stance phase and double stance phase (p<0.001) in relation to the normal weight group. Conclusion: The reduction of the swing phase and the increase of the stance phase and double stance phase presented by the overweight group may be a result of increased instability that occurs during gait due to overweight.

Acute Physiological and Thermoregulatory Responses to Extended Interval Training in Endurance Runners: Influence of Athletic Performance and Age.

This study aimed to describe the acute impact of extended interval training (EIT) on physiological and thermoregulatory levels, as well as to determine the influence of athletic performance and age effect on the aforementioned response in endurance runners. Thirty-one experienced recreational male endurance runners voluntarily participated in this study. Subjects performed EIT on an outdoor running track, which consisted of 12 runs of 400 m. The rate of perceived exertion, physiological response through the peak and recovery heart rate, blood lactate, and thermoregulatory response through tympanic temperature, were controlled. A repeated measures analysis revealed significant differences throughout EIT in examined variables. Cluster analysis grouped according to the average performance in 400 m runs led to distinguish between athletes with a higher and lower sports level. Cluster analysis was also performed according to age, obtaining an older group and a younger group. The one-way analysis of variance between groups revealed no significant differences (p≥0.05) in the response to EIT. The results provide a detailed description of physiological and thermoregulatory responses to EIT in experienced endurance runners. This allows a better understanding of the impact of a common training stimulus on the physiological level inducing greater accuracy in the training prescription. Moreover, despite the differences in athletic performance or age, the acute physiological and thermoregulatory responses in endurance runners were similar, as long as EIT was performed at similar relative intensity.

Concurrent fatigue and postactivation potentiation during extended interval training in long-distance runners / Fadiga concorrente e potenciação pós-ativação durante o treinamento intervalado extensivo em corredores de fundo / Fatiga concurrente y potenciación postactivación durante el entrenamiento interválico extendido en corredores de resistencia

The purpose of this study is to analyze acute effect of running extended interval training(EIT) on vertical jump (VJ) and handgrip strength (HS) performance in experienced endurance athletes. In order to analyze mechanical parameters of the VJ and HS between runs, sixteen experienced male athletes performed an EIT (4x3x400m). The results show that fatigue induced by EIT does not impair handgrip strength or VJ performance. A significant improvement (p< .05) was noted for VJ due to the postactivation potentiation (PAP) phenomenon. A positive correlation (r= .619, p= .011) was found between VJ and lactate. The results suggest that experienced long-distance runners can maintain their strength levels and, consequently, work capacity, despite the induced fatigue by the field training demand. Therefore, VJ performance during EIT can be used as an indicator of muscular adaptations to training and, together, with handgrip strength, become indicators of fatigue. These indicators allow proper prescription training routines...

"Fadiga concorrente e potenciação pós-ativação durante o treinamento intervalado extensivo em corredores de fundo." O objetivo do estudo é analisar a relação entre a fadiga e a potenciação pós-ativação (PPA) nos corredores de fundo durante uma sessão de treinamento típico, extensivo treinamento intervalado (ETI). Dezesseis atletas experientes executaram o ETI (4x3x400m) e se avaliou o desempenho entre as repetições e os parâmetros mecânicos associados ao salto vertical (SV) e à força de preensão manual. Os resultados mostram que o ETI não deteriora o desempenho dos atletas neste nesta prova e que inclusive há um aumento no SV (p< 0,05), devido ao fenômeno do PPA. Verificou-se uma correlação entre SV-lactado (r= 0,619, p= 0,011). Os dados obtidos sugerem que os atletas de resistência podem manter os níveis de força e a capacidade de trabalho apesar de fadiga induzida por ETI. O desempenho no SV para um ETI pode ser indicador de adaptações musculares do treino que, junto com a força de preensão manual, podem ser utilizadas como ferramentas para prescrição de treinamento...

"Fatiga concurrente y potenciación postactivación durante el entrenamiento interválico extendido en corredores de resistencia." El objetivo del estudio el efecto de un entrenamiento interválico extensivo (EIE) en el rendimiento en salto vertical (SV) y dinamometría manual en corredores de resistencia. Dieciséis atletas experimentados ejecutaron el EIE (4x3x400m), y se evaluó entre repeticiones el rendimiento en SV y parametros mecánicos asociados, y en fuerza de prensión manual. Los resultados muestran que EIE no deteriora el rendimiento en dichos test, e incluso aumenta significativamente en SV (p< 0,05) debido al fenómeno de potenciación postactivación (PPA). Se halló correlación entre SV y lactato (r= 0,619; p= 0,011). Los datos obtenidos sugieren que atletas de resistencia pueden mantener niveles de fuerza y capacidad de trabajo a pesar de la fatiga inducida por este entrenamiento en pista. El rendimiento en SV durante un EIE puede usarse como indicador de adaptaciones musculares al entrenamiento y, junto a fuerza de prensión manual, podrían utilizarse como herramientas para la prescripción del entrenamiento...