Thiago R. T. Santos

Biomechanical and Physiological Evaluation of Multi-Joint Assistance With Soft Exosuits

To understand the effects of soft exosuits on human loaded walking, we developed a reconfigurable multi-joint actuation platform that can provide synchronized forces to the ankle and hip joints. Two different assistive strategies were evaluated on eight subjects walking on a treadmill at a speed of 1.25 m/s with a 23.8 kg backpack: 1) hip extension assistance and 2) multi-joint assistance (hip extension, ankle plantarflexion and hip flexion). Results show that the exosuit introduces minimum changes to kinematics and reduces biological joint moments. A reduction trend in muscular activity was observed for both conditions. On average, the exosuit reduced the metabolic cost of walking by

A soft exosuit for patients with stroke: Feasibility study with a mobile off-board actuation unit

{\hbox{0.21}} \pm {\hbox{0.04}}~

Sports injuries profile of a first division Brazilian soccer team: a descriptive cohort study

and

Confiabilidade da mensuração do alinhamento pélvico no plano transverso durante o teste da ponte com extensão unilateral do joelho

{\hbox{0.67}} \pm {\hbox{0.09}}~{\hbox{W/kg}}

Passive stiffness of the ankle and plantar flexor muscle performance after Achilles tendon repair: a cross-sectional study

for hip extension assistance and multi-joint assistance respectively, which is equivalent to an average metabolic reduction of 4.6% and 14.6%, demonstrating that soft exosuits can effectively improve human walking efficiency during load carriage without affecting natural walking gait. Moreover, it indicates that actuating multiple joints with soft exosuits provides a significant benefit to muscular activity and metabolic cost compared to actuating single joint.

Myofascial force transmission in the lower limb: An in vivo experiment

In this paper, we present the first application of a soft exosuit to assist walking after stroke. The exosuit combines textile garments with cable driven actuators and is lighter and more compliant as compared to traditional rigid exoskeletons. By avoiding the use of rigid elements, exosuits offer greater comfort, facilitate donning/doffing, and do not impose kinematic restrictions on the wearer - all while retaining the ability to generate significant moments at target joints during walking. The stroke-specific exosuit adapted from previous exosuit designs provides unilateral assistance to the paretic limb during walking. This paper describes stroke-specific design considerations, the design of the textile components, the development of a research-focused, mobile off-board actuation unit capable of testing the exosuit in a variety of walking conditions, a real-time gait detection and control algorithm, and proof-of-principle data validating the use of the exosuit in the chronic stroke population. Ultimately, we demonstrate reliable tracking of poststroke gait, appropriate timing of assistive forces, and improvements in key gait metrics. These preliminary results demonstrate the feasibility and promise of exosuits for poststroke gait assistance and training. Future work will involve the creation of a portable, body-worn system based on the specifications obtained from such feasibility studies that will enable community-based rehabilitation.

Active control stabilization of pelvic position in the transverse plane: an evaluation of soccer players' performance.

ABSTRACT Objective: To establish the injury profile of soccer players from a first division Brazilian soccer team. In addition, we investigated the association between the characteristics of the injuries and the players age and position. Method: Forty-eight players from a Brazilian first division soccer team were followed during one season. Descriptive statistics were used to characterize the injury profile. Spearmans tests were used to verify the association between the number and severity of injuries and the players age. Chi-square test was used to verify the association between type of injury and players position. Fishers exact test was used to verify the association between the severity of injuries and players position. Results: The incidence of injuries was 42.84/1000 hours in matches and 2.40/1000 hours in training. The injury severity was 19.5±34.4 days off competition or training. Lower limb was the most common location of injury and most injuries were muscular/tendinous, overuse, non-recurrent, and non-contact injuries. Players age correlated with the amount and severity of muscle and tendon injuries. Defenders had more minimal injuries (1-3 days lost), while forwards had more moderate (8-28 days lost) and severe injuries (>28 days lost). Furthermore, wingbacks had more muscle and tendon injuries, while midfielders had more joint and ligament injuries. Conclusion: The injury profile of the Brazilian players investigated in this study reflected regional differences in soccer practices. Results confirm the influence of the players age and position on the soccer injuries profile.

Força muscular e índice de fadiga dos extensores e flexores do joelho de jogadores profissionais de futebol de acordo com o posicionamento em campo

BACKGROUND: The bridge test with unilateral knee extension evaluates the stability of the trunk and pelvis. The evaluation of this stability can contribute to the understanding of the occurrence of musculoskeletal injuries. OBJECTIVES: To investigate the intra- and inter-rater reliability of a qualitative analysis and intra-test reliability of a quantitative analysis of transverse plane pelvic alignment during the bridge test with unilateral knee extension. METHOD: Thirty participants (24.73±4.24 years old) were tested. The qualitative analysis was conducted by asking two raters to judge the transverse plane pelvic alignment and its reliability was assessed with the weighted kappa coefficient (kw). The quantitative analysis was conducted by measuring the greatest pelvic tilt angle in transverse plane and its reliability was assessed by use of the intraclass correlation coefficient (ICC); the mean change, which was evaluated using 95% confidence interval of the mean difference (95%CI ) and Bland-Altman plot; and the quantification of measurement variability, which was assessed using standard error of measurement (SEM) and the coefficient of variation of the typical error (CVTE). In addition, the minimal detectable change (MDC95) was determined. RESULTS: The intra-rater reliability ranged from fair to moderate (kw=0.32 to 0.58) and the inter-rater reliability was substantial (kw=0.80). The intra-test reliability was excellent (ICC=0.82), the 95% CI ranged from -0.51o to 1.99o, the SEM was 2.38o and the CVTE was 28.75%. The MDC95 was 6.59o. CONCLUSIONS: The inter-rater reliability was greater than the intra-rater reliability; the intra-test reliability was excellent and showed no systematic or random error.

Capacidade de estabilização pélvica em nadadores de diferentes estilos

Highlights • The surgical ankle presented lower stiffness values than the non-surgical ankle in the same subject.• The surgical ankle presented lower stiffness than the non-surgical group.• The SU group had greater absolute asymmetry of ankle stiffness.• The SU group had greater absolute asymmetry of plantar flexor muscle work.

Muscular strength and fatigue index of knee extensors and flexors of professional soccer players according to their positioning in field

Anatomical studies have shown structural continuity between the lumbopelvic region and the lower limb. The present study aimed to verify how simultaneous changes on knee/hip positions modify the ankles resting position and passive torque. Thirty-seven subjects underwent an isokinetic assessment of ankle passive torque. The relationship between the absolute values of ankle passive resistance torque and the ankle angular position was used to calculate the dependent variables: ankle resting position (position in which the passive resistance torque is zero); and ankle passive torque at 0° (torque at the neutral position of the ankle in the sagittal plane). These measures were carried out under three test conditions: 0° at knee and 0° at hip (0°/0°); 90° at knee and 90° at hip (90°/90°); and, 135° at knee and 120° at hip (135°/120°). The results demonstrated that the ankle resting position shifted towards dorsiflexion when knee/hip position changed from 0°/0° to 90°/90° and shifted towards plantar flexion when knee/hip position changed from 90°/90° to 135°/120°, achieving values close to the ones at the position 0°/0°. Similarly, passive torque reduced when knee/hip position changed from 0°/0° to 90°/90°, but it increased when knee/hip position changed from 90°/90° to 135°/120°. The unexpected changes observed in ankle passive torque and resting position due to changes in knee and hip from 90°/90° to 135°/120°, cannot be explained exclusively by forces related to tissues crossing the knee and ankle. This result supports the existence of myofascial force transmission among lower limb joints.