Synchronization performance affects gait variability measures during cued walking.

BACKGROUND: Incorporating variability within gait rehabilitation offers a promising approach to restore functional capacity. However, it's success requires adequate synchronization, a parameter that lacks report in most of the literature regarding cued gait training. RESEARCH QUESTION: How changes to synchronization performance during fractal-like and isochronous cueing impacts gait variability measures? METHODS: We asked twelve young male participants to walk in synchronization to two different temporally structure cueing (isochronous [ISO] and fractal [FRC]). We have also manipulated the cueing's tempo by increasing and decreasing it by 5% to manipulate synchronization, resulting in six conditions (stimuli [ISO,FRC] x tempo [SLOW, NORMAL, FAST]). The normal condition was set from an uncued trial through the participant's self-paced stride time. Synchronization performance (ASYNC) and gait variability (fractal scaling and coefficient of variation) were calculated from stride time data ( -ISIs,CV-ISIs). Repeated measures analysis of variance or Aligned Rank Transform were conducted to determine significant differences between metronome tempo and stimuli for the dependent variables RESULTS: Our results showed a FAST tempo decreases synchronization performance (ASYNC) and leads to lower -ISIs, for both ISO and FRC stimuli. This indicates that when an individual exhibits poor synchronization during cued gait training, his/her gait variability patterns will not follow the temporal structure of the presented metronome. Specifically, if the individual poorly synchronizes to the cues, the gait patterns become more random, a condition typically observed in older adults and neurological patients, which runs contrary to the hypothesis when using fractal-like metronomes. SIGNIFICANCE: This study provides supporting evidence that measuring synchronization performance in cued training is fundamental for a proper clinical interpretation of its effects. This is particularly relevant for the recent and ongoing clinical research using fractal-like metronomes since the expected gait patterns are dependent on the synchronization performance. Randomized control trials must incorporate synchronization performance related measures.

Fatigue Evaluation through Machine Learning and a Global Fatigue Descriptor.

Research in physiology and sports science has shown that fatigue, a complex psychophysiological phenomenon, has a relevant impact in performance and in the correct functioning of our motricity system, potentially being a cause of damage to the human organism. Fatigue can be seen as a subjective or objective phenomenon. Subjective fatigue corresponds to a mental and cognitive event, while fatigue referred as objective is a physical phenomenon. Despite the fact that subjective fatigue is often undervalued, only a physically and mentally healthy athlete is able to achieve top performance in a discipline. Therefore, we argue that physical training programs should address the preventive assessment of both subjective and objective fatigue mechanisms in order to minimize the risk of injuries. In this context, our paper presents a machine-learning system capable of extracting individual fatigue descriptors (IFDs) from electromyographic (EMG) and heart rate variability (HRV) measurements. Our novel approach, using two types of biosignals so that a global (mental and physical) fatigue assessment is taken into account, reflects the onset of fatigue by implementing a combination of a dimensionless (0-1) global fatigue descriptor (GFD) and a support vector machine (SVM) classifier. The system, based on 9 main combined features, achieves fatigue regime classification performances of 0.82 ± 0.24, ensuring a successful preventive assessment when dangerous fatigue levels are reached. Training data were acquired in a constant work rate test (executed by 14 subjects using a cycloergometry device), where the variable under study (fatigue) gradually increased until the volunteer reached an objective exhaustion state.

The effects of training and detraining after an 8 month resistance and stretching training program on forward head and protracted shoulder postures in adolescents: Randomised controlled study.

PURPOSE: This study aimed to evaluate the effects of a 32-week resistance and stretching training program applied in Physical Education classes on forward head posture and protracted shoulder posture of Portuguese adolescents (15-17 years old). The detraining effects after a 16-week period were also measured. METHODS: This prospective, randomized and controlled study was conducted in two secondary schools in Portugal. One hundred and thirty adolescents with forward head and protracted shoulder posture were randomly assigned to a control or experimental group. The sagittal head, cervical and shoulder angle were measured before and after a 32-week time intervention period. The control group (n = 46) did only the Physical Education classes whereas the exercise group (n = 42) received a posture corrective exercise programme in addition to Physical Education classes. A 16 week detraining period followed the 32-week. RESULTS: Significant increase were observed in the cervical and shoulder angle in the experimental group following the 32 week-intervention period. After the 16-week detraining period no significant differences were observed in the three postural angles in the intervention group. CONCLUSIONS: The exercise intervention was successful at decreasing forward head and protracted shoulder in adolescents. Detraining period was not sufficient to reduce the overall training effects. This study supports the postural training and rehabilitation performed during Physical Education classes, with the aim of preventing and managing upper quadrant musculoskeletal pain. CLINICALTRIALS. GOV IDENTIFIER: NCT02190331.

Effects of Walking with Blood Flow Restriction on Excess Post-exercise Oxygen Consumption.

This study determined the influence of walking with blood flow restriction (BFR) on the excess post-exercise oxygen consumption (EPOC) of healthy young men. 17 healthy young men (22.1±2.9 years) performed graded treadmill exercise to assess VO2peak. In a randomized fashion, each participant performed 5 sets of 3-min treadmill exercise at their optimal walking speed with 1-min interval either with or without BFR. Participants were then seated in a chair and remained there for 30 min of recovery. Expired gases were continuously monitored during exercise and recovery. BFR increased the O2 cost of walking as well as its relative intensity and cumulative O2 deficit (p<0.05). The EPOC magnitude after walking with BFR was greater than in the non-BFR condition (p<0.05). No differences between conditions were seen for the duration of EPOC. The EPOC magnitude was no longer different between conditions after controlling for the differences in relative intensity and in the cumulative O2 deficit (p>0.05). These data indicate that walking with BFR increases the magnitude of EPOC. Moreover, they also demonstrate that such increment in EPOC is likely explained by the effects of BFR on walking relative intensity and cumulative O2 deficit.

Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P < 0.05). Upper trunk positioning had an effect on the knee submaximal torque (P < 0.05), observed as an increase in the knee passive submaximal torque when the cervical and thoracic spines were flexed (P < 0.05). In conclusion, other apparently mechanical unrelated body segments influence torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension.

Reliability and validity of angular measures through the software for postural assessment. Postural Assessment Software

Introducción: El análisis estático fotográfico de la postura con la ayuda de software específico es práctico para estudios a gran escala y facilita el diagnóstico, la planificación y acompañamiento de cualquier tratamiento fisioterapéutico. El objetivo fue determinar tanto test-retest e inter-calificadores fiabilidad y validez de la fotogrametría computerizado con el software de evaluación postural (SAP) en relación con goniometría. Materiales y métodos: Los goniómetros universales se pusieron en una pared del laboratorio, permitiendo la obtención de 4 medidas angulares. Una cámara digital se coloca en un trípode a una altura de 1,47 metros y a una distancia de 3 metros de la pared. Una fotografía fue tomada con los cuatro goniómetros y dos fotos más fueron tomadas cambiando los valores angulares de los goniometros entre cada foto, totalizando doce valores angulares diferentes. Cada fotografía fue analizada por los tres evaluadores utilizando el Software de Evaluación postural. Método de Bland---Altman se utilizó para documentar un acuerdo entre los evaluadores y entre Goniometría y Software de Evaluación postural. Resultados: No hubo diferencias estadísticamente significativas entre los dos métodos de evaluación: goniometría y el software de SAP. La gráfica de Bland-Altman ratificó la fuerte consistencia entre los métodos, con una diferencia media igual a 0,06. El uso de PAS software también mostró ser fiable intra-calificadores (los tres evaluadores no presentaron diferencias significativas entre la primera y la segunda medición) y tener una buena fiabilidad entre evaluadores, sin presentar diferencias estadísticamente significativas entre ellos. Conclusiones: Software de evaluación postural es un método preciso y fiable en comparación con la goniometría (AU)

Introduction. Static posture analysis with the aid of specific software with images is beneficial for large-scale studies and facilitates the diagnosis, planning and follow-up of any physiotherapy treatment. Therefore, this study aimed to determine test–retest and inter-rater reliability and validity of computerized photogrammetry using the Postural Assessment Software (PAS) in relation to goniometry. Materials and methods. Universal Goniometers were placed in a wall of the Lab, making it possible to obtain four angular measures. A digital camera was positioned on a tripod at a height of 147 cm and at a distance of three meters from the wall. A photo was taken with the four goniometers. Two more photos were taken, and the goniometer angles were changed within each photo, obtaining 12 different angular values. Each photograph was analyzed by the three raters using the Postural Assessment Software. Bland–Altman method was used to document the agreement between raters and between Goniometry and Postural Assessment Software. Results. There were no statistical differences between the two evaluation methods: goniometry and PAS software. The Bland–Altman graph supported the strong consistency between methods, with an average difference equal to 0.06. The use of PAS software was also shown to be intra-rater reliable, with the three raters (A, p = 0.17; B, p = 0.31; C, p = 0.17) with no statistical significant differences between the first and the second measurement, and to have good inter-rater reliability with no statistical differences between raters. Conclusions. Postural Assessment Software is an accurate and reliable method when compared to the goniometry (AU)

Effects of different arm external loads on the scapulo-humeral rhythm.

OBJECTIVE: To investigate the effects of the magnitude of the external load, applied on the hand, on the orientation of the shoulder girdle (scapulo-humeral rhythm). DESIGN: Thirty subjects performed both arms' elevation in three planes of elevation: sagittal (anteflexion), frontal (abduction), and scapular (scaption). Measurements were performed against five levels of external load (0-4 kg), on each plane of elevation. BACKGROUND: Some controversy exists whether additional load influences the SHR. Moreover, no data are available on the SHR during arm abduction and anteflexion. METHODS: The SHR was recorded by means of a six degree of freedom electromagnetic tracking device. RESULTS: The external load applied on the hand affects scapular three-dimensional position: scapular protraction is particularly affected on abduction and scaption; scapular latero-rotation on anteflexion and abduction; and scapular spinal tilt on anteflexion. CONCLUSIONS: The magnitude of the external load, applied on the hand, influences the scapular position and the scapulo-humeral rhythm, particularly on abduction. Those effects are visible on scapular latero-rotation and spinal tilt, during anteflexion, and on scapular protraction during scaption. Additionally, the initial position of the shoulder girdle seems to play an important role on the definition of the individual SHR pattern. RelevanceThis study can provide a basis for evaluation of shoulder pathology associated with abnormal scapular kinematics.