Validity and reproducibility of foot motion analysis using a stretch strain sensor

Application of stretchable strain sensors and an inertial measurement unit for simulative tension analysis of the calcaneofibular ligament in formalin-fixed cadavers

BACKGROUND

The calcaneofibular ligament, a component of the lateral ligament complex of the ankle joint, plays an essential role in ankle-joint stability. To understand the mechanism of sprain-induced calcaneofibular ligament injury, the effect of ankle positions on calcaneofibular ligament tension needs to be ascertained.

METHODS

We propose a convenient method that combines stretchable strain sensors and an inertial measurement unit for simulative tension analysis of the calcaneofibular ligament in formalin-fixed cadavers. The stretchable strain sensor was pre-stretched approximately 1.3 times and, then set along the direction of the calcaneofibular ligament; a capacitance value from the sensor was used as a parameter to reflect the tension generated. Accurate three-axial inertial measurement unit-based monitoring of joint angles was undertaken for ten cadaveric ankles in measurements at 10° intervals from 30° plantarflexion to 20° dorsiflexion, followed by the investigation of additional effects with 10° inversion and eversion.

FINDINGS

Two-way repeated-measures ANOVA revealed a significant interactive effect for plantar/dorsiflexion × inversion/eversion and main effects for plantar/dorsiflexion and inversion/eversion. Post hoc pairwise analysis confirmed that 20° dorsiflexion or 10° inversion induces tension, whereas 10° eversion causes relaxation. Moreover, a promotional interactive effect by 20° dorsiflexion and 10° inversion and an offsetting effect by 10° eversion to 20° dorsiflexion were revealed. The measured values showed high levels of reliability and reproducibility (intraclass correlation coefficient [1,1] = 0.89).

INTERPRETATION

These results appropriately demonstrate the tensile action of calcaneofibular ligament. The novel approach investigated herein potentially opens new avenues for precise ligament-function evaluation.

In-shoe multi-segment foot kinematics measurement during the stance phase of running using a stretch strain sensor

Multi-segment foot kinematics during shod running are difficult to investigate in clinical settings. Stretch strain sensors can measure foot kinematics; however, whether they can evaluate foot kinematics during shod running or at the midfoot kinematics remains unclear. The aim of this study was to investigate the stretch strain sensor could reveal differences between shod and barefoot conditions and midfoot kinematics during running. Eighteen healthy adults were included in the study. A stretch strain sensor and three-dimensional motion capture system were used to measure foot kinematics during barefoot and shod running with a rearfoot strike pattern. The correlation between the amplitudes of the two signals during barefoot running was investigated, and the similarity between the two signals was evaluated using the cross-correlation coefficient. Statistical parametric mapping was used to compare shod and barefoot conditions. Shod running had significantly lower sensor strain from 30 % to 100 % stance compared to barefoot running (p < 0.05). The sensor amplitude was significantly correlated with the shank-rearfoot frontal (r = 0.668, p = 0.002), the rearfoot-midfoot transverse (r = 0.546, p = 0.02), and the midfoot-forefoot sagittal planes (r = 0.563, p = 0.01). A high cross-correlation was observed between the sensor signal and the shank-rearfoot sagittal, frontal, and transverse planes and the midfoot-forefoot sagittal plane. This sensor can be used to investigate foot kinematics during shod running. The sensor signal mainly reflects the shank-rearfoot frontal and midfoot-forefoot sagittal planes, as well as the maximum kinematic range of the rearfoot-midfoot transverse plane.

Research status of polysiloxane-based piezoresistive flexible human electronic sensors

Flexible human body electronic sensor is a multifunctional electronic device with flexibility, extensibility, and responsiveness. Piezoresistive flexible human body electronic sensor has attracted the extensive attention of researchers because of its simple preparation process, high detection sensitivity, wide detection range, and low power consumption. However, the wearability and affinity to the human body of traditional flexible human electronic sensors are poor, while polysiloxane materials can be mixed with other electronic materials and have good affinity toward the human body. Therefore, polysiloxane materials have become the first choice of flexible matrixes. In this study, the research progress and preparation methods of piezoresistive flexible human electronic sensors based on polysiloxane materials in recent years are summarized, the challenges faced in the development of piezoresistive flexible human electronic sensors are analyzed, and the future research directions are prospected.

Wearables for Running Gait Analysis: A Systematic Review

BACKGROUND

Running gait assessment has traditionally been performed using subjective observation or expensive laboratory-based objective technologies, such as three-dimensional motion capture or force plates. However, recent developments in wearable devices allow for continuous monitoring and analysis of running mechanics in any environment. Objective measurement of running gait is an important (clinical) tool for injury assessment and provides measures that can be used to enhance performance.

OBJECTIVES

We aimed to systematically review the available literature investigating how wearable technology is being used for running gait analysis in adults.

METHODS

A systematic search of the literature was conducted in the following scientific databases: PubMed, Scopus, Web of Science and SPORTDiscus. Information was extracted from each included article regarding the type of study, participants, protocol, wearable device(s), main outcomes/measures, analysis and key findings.

RESULTS

A total of 131 articles were reviewed: 56 investigated the validity of wearable technology, 22 examined the reliability and 77 focused on applied use. Most studies used inertial measurement units (n = 62) [i.e. a combination of accelerometers, gyroscopes and magnetometers in a single unit] or solely accelerometers (n = 40), with one using gyroscopes alone and 31 using pressure sensors. On average, studies used one wearable device to examine running gait. Wearable locations were distributed among the shank, shoe and waist. The mean number of participants was 26 (± 27), with an average age of 28.3 (± 7.0) years. Most studies took place indoors (n = 93), using a treadmill (n = 62), with the main aims seeking to identify running gait outcomes or investigate the effects of injury, fatigue, intrinsic factors (e.g. age, sex, morphology) or footwear on running gait outcomes. Generally, wearables were found to be valid and reliable tools for assessing running gait compared to reference standards.

CONCLUSIONS

This comprehensive review highlighted that most studies that have examined running gait using wearable sensors have done so with young adult recreational runners, using one inertial measurement unit sensor, with participants running on a treadmill and reporting outcomes of ground contact time, stride length, stride frequency and tibial acceleration. Future studies are required to obtain consensus regarding terminology, protocols for testing validity and the reliability of devices and suitability of gait outcomes.

CLINICAL TRIAL REGISTRATION

CRD42021235527.

Influence of a novel elastic foot orthosis in foot motion during locomotion in adults with mild flatfoot

BACKGROUND

Collapse of the foot arch is a one of the risk factors in medial tibial stress syndrome. Custom-made foot orthoses are used to reduce the collapse of foot arch, but the orthoses are designed for a specific shoe and cannot be used in other shoes. We developed an elastic foot orthosis that is highly fitted on the foot using thin films, is lightweight, and can be used with any shoe or without shoes. The purpose of this study was to investigate foot kinematics with our elastic foot orthosis during walking and running.

METHODS

We recruited 30 participants with asymptomatic flatfoot for this study. Foot kinematic data were recorded for treadmill walking, treadmill running, and over-ground walking. Foot kinematics were recorded in three conditions, barefoot (BF), with the elastic foot orthosis (EFO), and with sham foot orthosis (SFO), and foot strain was measured using a stretch strain sensor. The difference in foot strain from initial contact to maximum strain during gait was calculated as loading arch strain, which was reflected as forefoot eversion excursion. A one-way analysis of variance with Bonferroni test was performed to compare the loading arch strain among the three conditions.

RESULTS

In all tasks, loading arch strain with the EFO was significantly less than that in the BF and SFO conditions. Loading arch strain with the SFO was significantly more than that of BF in the treadmill gait condition.

CONCLUSION

Our results indicate that the EFO decreased foot strain during locomotion compared to without the EFO and is capable of supporting the foot arch during locomotion.

Potential of Internet of Medical Things (IoMT) applications in building a smart healthcare system: A systematic review

Sudden spurting of Corona virus disease (COVID-19) has put the whole healthcare system on high alert. Internet of Medical Things (IoMT) has eased the situation to a great extent, also COVID-19 has motivated scientists to make new 'Smart' healthcare system focusing towards early diagnosis, prevention of spread, education and treatment and facilitate living in the new normal. This review aims to identify the role of IoMT applications in improving healthcare system and to analyze the status of research demonstrating effectiveness of IoMT benefits to the patient and healthcare system along with a brief insight into technologies supplementing IoMT and challenges faced in developing a smart healthcare system. An internet-based search in PUBMED, Google Scholar and IEEE Library for english language publications using relevant terms resulted in 987 articles. After screening title, abstract, and content related to IoMT in healthcare and excluding duplicate articles, 135 articles published in journal with impact factor ≥1 were eligible for inclusion. Also relevant articles from the references of the selected articles were considered. The habituation of IoMT and related technology has resolved several difficulties using remote monitoring, telemedicine, robotics, sensors etc. However mass adoption seems challenging due to factors like privacy and security of data, management of large amount of data, scalability and upgradation etc. Although ample knowledge has been compiled and exchanged, this structured systematic review will help the healthcare practitioners, policymakers/decision makers, scientists and researchers to gauge the applicability of IoMT in healthcare more efficiently.