Search Results (10)

Chronic ankle instability (CAI) is characterized by impaired ankle joint position sense (JPS) and compromised balance. Despite previous studies investigating the correlation between ankle JPS and balance in individuals with CAI, the potential mediating effect of pain in this relationship remains unclear. Understanding the role of pain as a mediator between ankle JPS and balance could provide valuable insights into the complex interplay among these variables in individuals with CAI. Therefore, further research is needed to elucidate the mediating effect of pain and its implications in assessing and managing ankle JPS and balance deficits in individuals with CAI. This cross-sectional study aimed to investigate the mediating role of pain in the association between ankle JPS and balance in individuals with unilateral CAI. Methods: Fifty-five individuals diagnosed with CAI participated in this study. Ankle JPS was assessed using a digital inclinometer, whereas the balance was measured using a computerized dynamic posturography device. Results: Participants with CAI showed impaired ankle JPS in the affected leg compared to that in the asymptomatic leg (p < 0.001). Ankle JPS errors were greater in both dorsiflexion and plantarflexion directions in the CAI. Balance was compromised in the CAI leg (p < 0.001). Moderate correlations (p < 0.001, r = 0.31 to 0.48) were found between the balance variables. Pain significantly mediated the ankle JPS-balance relationship in the CAI (p < 0.05, Sobel test). The findings suggest that individuals with CAI exhibit impaired ankle JPS and compromised balance. Pain plays a mediating role in the association between ankle JPS and balance in individuals with CAI. These results highlight the importance of considering pain as a potential mediator when assessing and treating balance issues in individuals with CAI. Healthcare professionals should incorporate assessments of ankle JPS and pain into the management of interventions that address these factors and improve balance and functional ability. Full article

Flexibility and light weight have become the development trends in the field of exoskeleton research. With high movement flexibility, low movable inertia and excellent wearable comfort, such a type of system is gradually becoming an exclusive candidate for applications such as military defense, rehabilitation training and industrial production. In this paper, aiming at assisting the walking of human lower limbs, a soft exosuit is investigated and developed based on the considerations of fabric structure, sensing system, cable-driven module, and control strategy, etc. Evaluation experiments are also conducted to verify its effectiveness. A fabric optimization of the flexible suit is performed to realize the tight bond between human and machine. Through the configuration of sensor nodes, the motion intention perception system is constructed for the lower limb exosuit. A flexible actuation unit with a Bowden cable is designed to improve the efficiency of force transmission. In addition, a position control strategy based on division of the gait phase is applied to achieve active assistance during plantar flexion of the ankle joint. Finally, to verify the assistive effectiveness of the proposed lower extremity exosuit, experiments including a physiological metabolic test and a muscle activation test are conducted. The experiment results show that the exosuit proposed in this paper can effectively reduce the metabolic consumption and muscle output of the human body. The design and methodology proposed in this paper can be extended to similar application scenarios. Full article

Functional ankle instability (FAI) is a condition that causes mechanical alterations to the ankle joint and leads to disability. Fear of movement can significantly influence physical factors, and understanding their relationship is crucial in assessing and managing individuals with FAI. The present study aimed to (1) assess the impact of kinesiophobia on ankle joint position sense (JPS) and postural control and (2) evaluate if kinesiophobia can predict JPS and postural control in FAI individuals. This cross-sectional study included 55 FAI individuals. The Tampa Scale of Kinesiophobia (TSK) score was used to measure kinesiophobia. The ankle JPS was evaluated using a digital inclinometer. The individuals were asked to actively reposition to the target position of 10° and 15° of dorsiflexion and plantarflexion. The reposition accuracy is measured in degrees. The static postural control was evaluated in unilateral stance using a stabilometric force platform, including assessments for the ellipse area, anterior to posterior sway, and medial to lateral sway in mm². Kinesiophobia showed a significant positive correlation (moderate) with the ankle JPS errors in dorsiflexion (10°: r = 0.51, p < 0.001; at 15°: = r = 0.52, p < 0.001) and plantarflexion (10°: r = 0.35, p = 0.009; at 15°: = r = 0.37, p = 0.005). Kinesiophobia also showed significant positive (moderate) correlation with postural control variables (ellipse area: r = 0.44, p = 0.001; Anterior–Posterior sway: r = 0.32, p = 0.015; Medial–Lateral sway: r = 0.60, p < 0.001). Kinesiophobia significantly predicted ankle JPS (p < 0.05) and postural control (p < 0.05). Increased fear of movement is associated with increased ankle JPS errors and postural sway in FAI individuals. Therefore, assessment of these factors is critical in FAI individuals. Full article

Ankle injuries may adversely increase the risk of injury to the joints of the lower extremity and can lead to various impairments in workplaces. The purpose of this study was to predict the ankle angles by developing a footwear pressure sensor and utilizing a machine learning technique. The footwear sensor was composed of six FSRs (force sensing resistors), a microcontroller and a Bluetooth LE chipset in a flexible substrate. Twenty-six subjects were tested in squat and stoop motions, which are common positions utilized when lifting objects from the floor and pose distinct risks to the lifter. The kNN (k-nearest neighbor) machine learning algorithm was used to create a representative model to predict the ankle angles. For the validation, a commercial IMU (inertial measurement unit) sensor system was used. The results showed that the proposed footwear pressure sensor could predict the ankle angles at more than 93% accuracy for squat and 87% accuracy for stoop motions. This study confirmed that the proposed plantar sensor system is a promising tool for the prediction of ankle angles and thus may be used to prevent potential injuries while lifting objects in workplaces. Full article

We explored the effects of 6-week whole-body vibration (WBV) and balance training programs on female athletes with chronic ankle instability (CAI). This randomized controlled study involved female athletes with dominant-leg CAI. The participants were randomly divided into three groups: WBV training (Group A), balance training (Group B), and nontraining (control group; Group C). Groups A and B performed three exercise movements (double-leg stance, one-legged stance, and tandem stance) in 6-week training programs by using a vibration platform and balance ball, respectively. The Star Excursion Balance Test (SEBT), a joint position sense test, and an isokinetic strength test were conducted. In total, 63 female athletes with dominant-leg CAI were divided into three study groups (all n = 21). All of them completed the study. We observed time-by-group interactions in the SEBT (p = 0.001) and isokinetic strength test at 30°/s of concentric contraction (CON) of ankle inversion (p = 0.04). Compared with the control group, participants of the two exercise training programs improved in dynamic balance, active repositioning, and 30°/s of CON and eccentric contraction of the ankle invertor in the SEBT, joint position sense test, and isokinetic strength test, respectively. Furthermore, the effect sizes for the assessed outcomes in Groups A and B ranged from very small to small. Female athletes who participated in 6-week training programs incorporating a vibration platform or balance ball exhibited very small or small effect sizes for CAI in the SEBT, joint position sense test, and isokinetic strength test. No differences were observed in the variables between the two exercise training programs. Full article

Plyometric exercise has been suggested for knee injury prevention in sports participation, but studies on ankle plyometric training are limited. This study aims to investigate the change of joint position sense and neuromuscular activity of the unstable ankle after six-week integrated balance/plyometric training and six-week plyometric training. Thirty recreational athletes with functional ankle instability were allocated into three groups: plyometric group (P) vs. plyometric integrated with balance training group (BP) vs. control group (C). Ankle joint position sense, integrated electromyography (EMG), and balance adjusting time during medial single-leg drop-landing tasks were measured before and after the training period. Following the six-week period, both training groups exhibited a lower absolute error in plantar flexion (P group: pre: 3.79° ± 1.98°, post: 2.20° ± 1.31°, p = 0.016; BP group: pre: 4.10° ± 1.87°, post: 2.94° ± 1.01°, p = 0.045), and the integrated group showed a lower absolute error in inversion angles (pre 2.24° ± 1.44° and post 1.48° ± 0.93°, p = 0.022), and an increased integrated EMG of ankle plantar flexors before landing. The plyometric group exhibited a higher integrated EMG of the tibialis anterior before and after landing (pre: 102.88 ± 20.93, post: 119.29 ± 38.33, p = 0.009 in post-landing) and a shorter adjusting time of the plantar flexor following landing as compared to the pre-training condition (pre: 2.85 ± 1.15 s, post: 1.87 ± 0.97 s, p = 0.006). In conclusion, both programs improved ankle joint position sense and muscle activation of the ankle plantar flexors during single-leg drop landing. The plyometric group showed a reduced adjusting time of the ankle plantar flexor following the impact from drop landing. Full article

For the controller of wearable lower-limb assistive devices, quantitative understanding of human locomotion serves as the basis for human motion intent recognition and joint-level motion control. Traditionally, the required gait data are obtained in gait research laboratories, utilizing marker-based optical motion capture systems. Despite the high accuracy of measurement, marker-based systems are largely limited to laboratory environments, making it nearly impossible to collect the desired gait data in real-world daily-living scenarios. To address this problem, the authors propose a novel exoskeleton-based gait data collection system, which provides the capability of conducting independent measurement of lower limb movement without the need for stationary instrumentation. The basis of the system is a lightweight exoskeleton with articulated knee and ankle joints. To minimize the interference to a wearer’s natural lower-limb movement, a unique two-degrees-of-freedom joint design is incorporated, integrating a primary degree of freedom for joint motion measurement with a passive degree of freedom to allow natural joint movement and improve the comfort of use. In addition to the joint-embedded goniometers, the exoskeleton also features multiple positions for the mounting of inertia measurement units (IMUs) as well as foot-plate-embedded force sensing resistors to measure the foot plantar pressure. All sensor signals are routed to a microcontroller for data logging and storage. To validate the exoskeleton-provided joint angle measurement, a comparison study on three healthy participants was conducted, which involves locomotion experiments in various modes, including overground walking, treadmill walking, and sit-to-stand and stand-to-sit transitions. Joint angle trajectories measured with an eight-camera motion capture system served as the benchmark for comparison. Experimental results indicate that the exoskeleton-measured joint angle trajectories closely match those obtained through the optical motion capture system in all modes of locomotion (correlation coefficients of 0.97 and 0.96 for knee and ankle measurements, respectively), clearly demonstrating the accuracy and reliability of the proposed gait measurement system. Full article

Over recent years, a growing body of research has highlighted the neural plastic effects of spinal manipulation on the central nervous system. Recently, it has been shown that spinal manipulation improved outcomes, such as maximum voluntary force and limb joint position sense, reflecting improved sensorimotor integration and processing. This study aimed to further evaluate how spinal manipulation can alter neuromuscular activity. High density electromyography (HD sEMG) signals from the tibialis anterior were recorded and decomposed in order to study motor unit changes in 14 subjects following spinal manipulation or a passive movement control session in a crossover study design. Participants were asked to produce ankle dorsiflexion at two force levels, 5% and 10% of maximum voluntary contraction (MVC), following two different patterns of force production (“ramp” and “ramp and maintain”). A significant decrease in the conduction velocity (p = 0.01) was observed during the “ramp and maintain” condition at 5% MVC after spinal manipulation. A decrease in conduction velocity suggests that spinal manipulation alters motor unit recruitment patterns with an increased recruitment of lower threshold, lower twitch torque motor units. Full article

Background: Ankle sprains are common among physically active individuals, especially among athletes. Majority of those who suffer ankle sprains have residual symptoms including pain, episodes of giving way, compromised proprioception and neuromuscular control, and re-injury leading to chronic ankle instability. The aim of this study was to see the effect of chronic ankle sprain on pain, range of motion, proprioception, and, static and dynamic balance among athletes. Methods: A total of 80 athletes, aged 18 to 25 years, involved in track-and-field sports were invited to participate in this study. They were divided in two groups. Athletes with history of grade 1 or 2 ankle sprain on either side requiring medical care who reported at least three episodes of ankle giving way in past 12 months were included in group A. An equal number of healthy athletes without any history of ankle sprain or injury in the lower limbs in the past one year matched by sex, age, height, weight, and limb dominance, were included in group B (control). Outcome measures: Participant’s pain, range of motion, proprioception and balance (static and dynamic) was measured using visual analog scale, half circle goniometer, degree of foot position sense, single leg stance time and Y-balance test respectively. Results: Although there were no differences in the active ankle joint range of motion (p > 0.05) in comparison to the control group, athletes with chronic ankle sprain reported mild pain and statistically significant (p < 0.05) deficits in foot proprioception, static and dynamic balance. Conclusions: Deficits in foot proprioception, static and dynamic balance even one year after the ankle sprain could be the reason for limitations in the dynamic defense system of the joint that predisposes to recurrent injury and instability. It is essential to understand the normal clinical course and risk factors for athletes who sustain sprain before devising a long term comprehensive rehabilitation program that focuses on mechanical and functional insufficiencies in order to improve their functional performance and prevent the risk of recurrent sprain. Full article

Tai Chi (TC) can be considered safe and effective intervention to improve pain and pain-related functional disability. However, it is unclear that whether aging individuals with Chronic Non-Specific Low Back Pain (CNS-LBP) can achieve positive results. This study, therefore, attempted to explore the effects of TC on pain and functional disability in CNS-LBP patients aged 50 years old or above. Forty-three individuals (aged 50 years old or above) with CNS-LBP were randomly assigned into three groups: Chen-Style TC group (n = 15), Core Stabilization training (CST) group (n = 15), and control group (n = 13). Participants in the TC group participated in Chen-style TC training program (three 60-min sessions per week for 12 weeks), individuals in CST group received 12-week Core Stabilization exercise on the Swiss ball, whereas individuals in the control group maintained their unaltered lifestyle. Pain intensity as primary outcome was measured using the Visual Analogue Scale (VAS), A BiodexSystem 3 isokinetic dynamometer was used to measure knee and ankle joint position sense (JPS) as secondary outcomes at baseline and after the 12-week intervention. TC and CST have significant effects in VAS for CNS-LBP patients (p< 0.01, TC group OR CST group versus control group in mean of the post-minus-pre assessment). However, the feature of joint position sense (JPS) of ankle inversion, ankle eversion and knee flexion did not occur, it showed no significant effects with TC and CST. TC was found to reduce pain, but not improve lower limb proprioception in patients with CNS-LBP. Future research with larger sample sizes will be needed to achieve more definitive findings on the effects of TC on both pain and lower limb proprioception in this population. Full article