AN ELASTIC EXERCISE BAND MOUNTED WITH A BANDCIZER? CAN DIFFERENTIATE BETWEEN COMMONLY PRESCRIBED HOME EXERCISES FOR THE SHOULDER

Background

Home‐exercise is commonly prescribed for rehabilitation of the shoulder following injury. There is a lack of technology available to monitor if the patient performs the exercises as prescribed.

Purpose

The purpose of this study was to investigate the validity of using three dimensional (3D) gyroscope data recorded with the Bandcizer™ sensor to differentiate between three elastic band exercises performed in the shoulder joint: abduction, flexion, and external rotation.

Design

Concurrent validity study.

Methods

This study was performed over two phases. In the first phase, 20 subjects performed three sets of 10 of shoulder abduction, external rotation and flexion exercises with a Thera‐Band mounted with a Bandcizer, while supervised by a physical therapist. The Bandcizer has an inbuilt three‐dimensional gyroscope, capable of measuring angular rotation. Gyroscope data were analyzed in Matlab, and a one‐way ANOVA was used to test for significant differences between each of the three exercises. An algorithm was then created in Matlab based on the exercise‐data from the gyroscope, to enable differentiation between the three shoulder exercises. Twenty new subjects were then recruited to cross‐validate the algorithm and investigate if the algorithm could differentiate between the three different shoulder exercises.

Results

A blinded assessor using the Matlab algorithm could correctly identify 56 out of 60 exercise sets. The kappa agreement for the three exercises ranged between 0.86‐0.91.

Conclusion

The ability to differentiate between the home exercises performed by patients after shoulder injury has great implications for future clinical practice and research. When home exercises are the treatments‐of‐choice, clinicians will be able to quantify if the patient performed the exercise as intended. Further research should be aimed at investigating the feasibility of using the Bandcizer™ in a home‐based environment.

Word count

2429

Level of Evidence

2     

Detecting absolute human knee angle and angular velocity using accelerometers and rate gyroscopes

Knee joint angle and angular velocity were calculated in real time during standing up and sitting down. Two small modules comprising rate gyroscopes and accelerometers were attached to the thigh and shank of two able-bodied volunteers and one T₅ ASIA(A) paraplegic assisted by functional electrical stimulation (FES). The offset and drift of the rate gyroscopes was compensated for by auto-resetting and auto-nulling algorithms. The tilt of the limb segments was calculated by combining the signals of the accelerometer and the rate gyroscope. The joint angle was calculated as the difference in tilt of the segments. The modules were also tested on a two-dimensional model. The mean differences between the rate gyroscope-accelerometer system and the reference goniometer for the model, able-bodied and paraplegic standing trials were 2.1°, 2.4° and 2.3° respectively for knee angle and 2.3° s⁻¹, 5.0° s⁻¹ and 11.8° s⁻¹ respectively for knee velocity. The rate gyroscope-accelerometer system was more accurate than using the accelerometer as a tilt meter, possibly due to the greater bandwidth of the rate gyroscope-accelerometer system.     

全膝关节置换术两种股骨假体定位的比较

[目的]探讨应用陀螺仪股骨髓外定位截骨行全膝关节置换的可行性及临床疗效.[方法]回顾性分析2019年3月-2020年1月行初次全膝关节置换的53例患者(61膝)的临床资料,其中27例使用陀螺仪髓外定位股骨侧截骨行全膝关节置换术(髓外组),34例行传统髓内导向杆定位股骨侧截骨全膝关节置换术(髓内组),比较两组临床疗效.[...     

Periodical gait asymmetry assessment using real-time wireless gyroscopes gait monitoring system

A real-time gait monitoring system that incorporates an immediate and periodical assessment of gait asymmetry is described. This system was designed for gait analysis and rehabilitation of patients with pathologic gait. It employs wireless gyroscopes to measure the angular rate of the thigh and shank in real time. Cross-correlation of the lower extremity (Cc_norm), and normalized Symmetry Index (SI_norm) are implemented as new approaches to periodically determine the gait asymmetry in each gait cycle. Cc_norm evaluates the signal patterns measured by wireless gyroscopes in each gait cycle. SI_norm determines the movement differences between the left and right limb. An experimental study was conducted to examine the viability of these methods. Artificial asymmetrical gait was simulated by placing a load on one side of the limbs. Results showed that there were significant differences between the normal gait and asymmetrical gait (p?<?0.01). They also indicated that the system worked well in periodically assessing the gait asymmetry.     

人脐静脉内皮细胞的体外培养及微重力对其增殖的影响

目的探讨微重力环境对人脐静脉血管内皮细胞增殖的作用。方法取健康产妇剖宫产术后脐带，用胶原酶Ⅰ消化血管内皮细胞，进行原代培养，在碱性成纤维细胞生长因子(bFGF)作用下细胞长期传代；将内皮细胞置于回转器内模拟太空微重力培养，同时设地面静止培养对照，测定72h内血管内皮细胞增殖水平。结果模拟微重力下细胞增殖高于对照组。结论培养的脐静脉血管内皮细胞对微重力环境敏感。     

Classification Accuracies of Physical Activities Using Smartphone Motion Sensors

Background

Over the past few years, the world has witnessed an unprecedented growth in smartphone use. With sensors such as accelerometers and gyroscopes on board, smartphones have the potential to enhance our understanding of health behavior, in particular physical activity or the lack thereof. However, reliable and valid activity measurement using only a smartphone in situ has not been realized.

Objective

To examine the validity of the iPod Touch (Apple, Inc.) and particularly to understand the value of using gyroscopes for classifying types of physical activity, with the goal of creating a measurement and feedback system that easily integrates into individuals’ daily living.

Methods

We collected accelerometer and gyroscope data for 16 participants on 13 activities with an iPod Touch, a device that has essentially the same sensors and computing platform as an iPhone. The 13 activities were sitting, walking, jogging, and going upstairs and downstairs at different paces. We extracted time and frequency features, including mean and variance of acceleration and gyroscope on each axis, vector magnitude of acceleration, and fast Fourier transform magnitude for each axis of acceleration. Different classifiers were compared using the Waikato Environment for Knowledge Analysis (WEKA) toolkit, including C4.5 (J48) decision tree, multilayer perception, naive Bayes, logistic, k-nearest neighbor (kNN), and meta-algorithms such as boosting and bagging. The 10-fold cross-validation protocol was used.

Results

Overall, the kNN classifier achieved the best accuracies: 52.3%–79.4% for up and down stair walking, 91.7% for jogging, 90.1%–94.1% for walking on a level ground, and 100% for sitting. A 2-second sliding window size with a 1-second overlap worked the best. Adding gyroscope measurements proved to be more beneficial than relying solely on accelerometer readings for all activities (with improvement ranging from 3.1% to 13.4%).

Conclusions

Common categories of physical activity and sedentary behavior (walking, jogging, and sitting) can be recognized with high accuracies using both the accelerometer and gyroscope onboard the iPod touch or iPhone. This suggests the potential of developing just-in-time classification and feedback tools on smartphones.     

Jump height from inertial recordings: A tutorial for a sports scientist

Jump performance provides meaningful information both for sporting and clinical needs. Current state of the art in jump performance assessment is laboratory-bound; however, out-of-the-laboratory methods are desirable. Therefore, the purposes of the present investigation were (a) to explore whether utilizing a novel analytical approach minimizes the bias between inertial recording unit (IMU)-based and jump mat-based jump height estimates and (b) to provide a thorough tutorial for a sport scientist (see Appendix S1 ) to facilitate standardization of jump height estimation. Forty-one women, men, and boys aged 6 to 77 years completed three maximal countermovement jumps without arm swing, which were concurrently registered with a jump mat, and an IMU worn in low lumbar region. Excellent agreement between the novel IMU-based jump height and jump mat jump height was observed (mean IMU 22.6 [8.3] cm, mean jump mat 22.7 [8.9], mean bias −0.1 cm [95% limits of agreement −4.5 cm to 4.4 cm; P = .826], and intra-class correlation coefficient 0.97 [95% CI 0.94 to 0.98, P < .001]). In conclusion, inertial recordings conducted with lightweight IMUs worn on the hip provide a valid and feasible assessment of jump height among people with varying athletic ability. Inertial signals have the potential to afford (at least semi-) automated analysis pipeline with low labor cost thus being potentially feasible in applied settings such as in professional sports or in the clinics.     

可穿戴式跌倒检测及防护装置的研究现状

跌倒是影响老年人身心健康的主要因素之一,因此研制有效检测跌倒且能够保护跌倒老人的装置显得尤为重要。跌倒检测及防护装置主要包含三大模块:检测模块、控制模块和防护模块。本文总结了现有的可穿戴式跌倒检测和防护技术,对系统三大模块的功能和技术以及系统中所用的主要算法进行了具体分析,比较了现有的三种可穿戴式跌倒检测和防护装置的结构原理及各自技术上的优缺点,最后探讨了可穿戴式跌倒检测及防护装置未来的发展趋势,认为可穿戴式跌倒检测及防护装置还有很大的发展空间与市场前景。     

数字陀螺仪与超声集合引导模拟经皮穿刺术

目的 通过模拟实验验证数字陀螺仪与超声集合引导经皮穿刺术的精准性。方法 自制两种一次性实验体模：体模A内置直径1.0 cm球形水囊,水囊中心距A表面5.0 cm,用于模拟浅表脏器靶标的穿刺实验;体模B内置直径1.5 cm水囊,水囊中心距B表面10.0 cm,用于模拟深部脏器靶标的穿刺实验。对体模A组采用斜向穿刺进针,体模B组采用垂直方向穿刺进针。以数字陀螺仪与超声集合引导穿刺和超声定位徒手穿刺方法,分别对A、B重复穿刺10次,记录每组穿刺命中次数,计算命中率。结果 对体模A组采用数字陀螺仪与超声集合引导穿刺命中8次,命中率80.00%（8/10）;超声定位徒手穿刺命中3次,命中率30.00%（3/10）。对体模B组采用数字陀螺仪与超声集合引导穿刺,命中9次,命中率90.00%（9/10）;超声定位徒手穿刺命中4次,命中率40.00%（4/10）。数字陀螺仪与超声集合引导穿刺命中率均明显高于超声定位徒手穿刺（P均<0.05）。结论 数字陀螺仪与超声集合引导可为穿刺模拟实验中穿刺靶标提供精准的空间位置,精准引导穿刺针的进针角度和方向,有望成为一种全新的经皮穿刺导航技术。