A Cable-Driven Portable Fitness Chair with Programmable Resistance for Effective Muscle Training.

The COVID-19 pandemic has changed the lifestyle of society and the interest in health and fitness has greatly increased, accordingly. Recently, motorized devices that allow fine and automatic adjustment of resistance without physically changing the applied weight have been released to the market. In fact, these devices have eased the resistance-changing process. However, such devices are still not portable as they must be mounted on the wall and their resistance control needs to be improved to increase the efficiency of strength training. This study introduces a portable chair-shaped fitness device that allows inducing various resistance profiles. A compact, light, and robust cable-driven actuation module design was achieved by implementing a derailing prevention mechanism. The actuator covers resistance up to 120 N for each left and right arm separately. Exercise can be conducted by pulling the elastic handle connected to cable. The controller of the proposed device allows variation of resistance according to the joint range-of-motion (ROM) to make the workout more challenging but still safe through the full ROM. Viscous resistance, ascending resistance, and descending resistance profile can be provided. The experimental results shows that various muscle activation patterns can be provided by changing the resistance profile, which is important for effective training. The device can be used anywhere, at home or office, to perform various upper and lower body exercises or for physical self-care.

Lumbar Stability in Healthy Individuals and Low Back Pain Patients Quantified by Wall Plank-and-Roll Test.

BACKGROUND: Low back pain (LBP) has been linked to the degree of lumbar stability, but evaluating lumbar stability has remained a challenge. Previous research has shown that inertial sensors could be used to quantify motor patterns during the wall plank-and-roll (WPR) test, and that LBP may cause deviations in movement from the general motor patterns observed in healthy individuals. OBJECTIVE: To generalize the lumbar motor patterns during the WPR test in healthy individuals, and to analyze the effect of aging and LBP on the motor patterns during the WPR test. DESIGN: A descriptive, exploratory research with a convenience sample. This study is registered at the Clinical Research Information Service (Korea) under public trial registration numbers KCT0002481 and KCT0002533. SETTING: A biomechanics laboratory of a tertiary university hospital. PARTICIPANTS: 57 healthy individuals (23 men 36.7 ± 15.4 years old and 34 women 42.4 ± 17.7 years old) and 17 patients (5 men 48.4 ± 10.9 years old and 12 women 33.7 ± 9.9 years old) with axial LBP. METHODS: Participants performed the WPR test with 2 inertial sensors placed on the thoracic spine and sacrum. Relative angles between the sensors were calculated to quantify and examine lumbar motion in 3 anatomical planes: axial twist, kyphosis-lordosis, and lateral bending. MAIN OUTCOME MEASURES: General motor patterns during the WPR test in healthy participants were examined, stratified based on age, and changes based on age were analyzed. Motor patterns of LBP patients were compared with those from the healthy group. RESULTS: Movement in the kyphosis-lordosis and lateral bending axes showed little variation in healthy participants, whereas in the axial twist axis there were 2 dominant patterns. A χ 2 test revealed that the distributions of 2 motor patterns in the axial twist axis between the younger group and the older group were significantly different (P < .05). Furthermore, the older group had decreased lordosis at the static position (P = .02) and at the maximal rotating position (P = .03). Compared with the healthy group, LBP patients showed increasing lateral bending at the maximal rotating position (P = .007) and increased lateral bending excursion angle (P = .04) during the WPR test. CONCLUSIONS: A general lumbar motor pattern was observed during the WPR test in the healthy participants, but age contributed to variations in this general pattern. Comparison of motor patterns between healthy individuals and LBP patients revealed a different type of variation in the LBP patients. The results presented should be scrutinized with further research, characterizing specific variations in different subgroups of LBP patients. LEVEL OF EVIDENCE: III.

Unobtrusive Estimation of Cardiorespiratory Fitness with Daily Activity in Healthy Young Men.

Despite the importance of cardiorespiratory fitness, no practical method exists to estimate maximal oxygen consumption (VO2max) without a specific exercise protocol. We developed an estimation model of VO2max, using maximal activity energy expenditure (aEEmax) as a new feature to represent the level of physical activity. Electrocardiogram (ECG) and acceleration data were recorded for 4 days in 24 healthy young men, and reference VO2max levels were measured using the maximal exercise test. aEE was calculated using the measured acceleration data and body weight, while heart rate (HR) was extracted from the ECG signal. aEEmax was obtained using linear regression, with aEE and HR as input parameters. The VO2max was estimated from the aEEmax using multiple linear regression modeling in the training group (n = 16) and was verified in the test group (n = 8). High correlations between the estimated VO2max and the measured VO2max were identified in both groups, with a 15-hour recording being sufficient to produce a highly accurate VO2max estimate. Additional recording time did not significantly improve the accuracy of the estimation. Our VO2max estimation method provides a robust alternative to traditional approaches while only requiring minimal data acquisition time in daily life.

An assessment of the accuracy of a novel weight estimation device for children.

BACKGROUND: We sought to validate the accuracy and assess the efficacy of a newly developed electronic weight estimation device (ie, the rolling tape) for paediatric weight estimation. METHODS: We enrolled a convenience sample of children aged <17 years presenting to our emergency department who volunteered to participate in the study. The children's heights and weights were measured, and three researchers estimated these values using the rolling tape and Broselow tape at 5 min intervals. The weight estimates of researcher 1, researcher 2 and the Broselow tape were compared with measured values, and mean percentage error (MPE), root mean square error (RMSE) and percentage of estimates within 10% of the actual measured values were calculated. For 30 randomly selected subjects, we compared the time interval from the start of the measurement to the time that orders for epinephrine, defibrillation dose and instrument size could be given in a simulated arrest scenario. RESULTS: We enrolled 906 children (median age 4.0 years). For researcher 1, researcher 2 and the Broselow tape, MPE values were 0.11% (RMSE 2.61 kg), 1.41% (RMSE, 2.61 kg) and 1.72% (RMSE 5.41 kg), respectively, and the percentages of children with predictions within 10% of their actual weight were 75.1%, 75.7% and 60.6%, respectively. In the 30 simulated cases, the mean time for measurement to ordering was significantly shorter (25.8 s vs 35.5 s, p<0.001) for the rolling tape compared with the Broselow tape method. CONCLUSIONS: The rolling tape is a good weight estimation tool for children compared with other methods. The rolling tape method significantly decreased the time from weight estimation to orders for essential drug dose, instrument size and defibrillation dose for resuscitation.

Validation of Attitude and Heading Reference System and Microsoft Kinect for Continuous Measurement of Cervical Range of Motion Compared to the Optical Motion Capture System.

OBJECTIVE: To compare optical motion capture system (MoCap), attitude and heading reference system (AHRS) sensor, and Microsoft Kinect for the continuous measurement of cervical range of motion (ROM). METHODS: Fifteen healthy adult subjects were asked to sit in front of the Kinect camera with optical markers and AHRS sensors attached to the body in a room equipped with optical motion capture camera. Subjects were instructed to independently perform axial rotation followed by flexion/extension and lateral bending. Each movement was repeated 5 times while being measured simultaneously with 3 devices. Using the MoCap system as the gold standard, the validity of AHRS and Kinect for measurement of cervical ROM was assessed by calculating correlation coefficient and Bland-Altman plot with 95% limits of agreement (LoA). RESULTS: MoCap and ARHS showed fair agreement (95% LoA<10°), while MoCap and Kinect showed less favorable agreement (95% LoA>10°) for measuring ROM in all directions. Intraclass correlation coefficient (ICC) values between MoCap and AHRS in -40° to 40° range were excellent for flexion/extension and lateral bending (ICC>0.9). ICC values were also fair for axial rotation (ICC>0.8). ICC values between MoCap and Kinect system in -40° to 40° range were fair for all motions. CONCLUSION: Our study showed feasibility of using AHRS to measure cervical ROM during continuous motion with an acceptable range of error. AHRS and Kinect system can also be used for continuous monitoring of flexion/extension and lateral bending in ordinary range.

Measurement of Shoulder Range of Motion in Patients with Adhesive Capsulitis Using a Kinect.

Range of motion (ROM) measurements are essential for the evaluation for and diagnosis of adhesive capsulitis of the shoulder (AC). However, taking these measurements using a goniometer is inconvenient and sometimes unreliable. The Kinect (Microsoft, Seattle, WA, USA) is gaining attention as a new motion detecting device that is nonintrusive and easy to implement. This study aimed to apply Kinect to measure shoulder ROM in AC; we evaluated its validity by calculating the agreement of the measurements obtained using Kinect with those obtained using goniometer and assessed its utility for the diagnosis of AC. Both shoulders of 15 healthy volunteers and affected shoulders of 12 patients with AC were included in the study. The passive and active ROM of each were measured with a goniometer for flexion, abduction, and external rotation. Their active shoulder motions for each direction were again captured using Kinect and the ROM values were calculated. The agreement between the two measurements was tested with the intraclass correlation coefficient (ICC). Diagnostic performance using the Kinect ROM was evaluated with Cohen's kappa value. The cutoff values of the limited ROM were determined in the following ways: the same as passive ROM values, reflecting the mean difference, and based on receiver operating characteristic curves. The ICC for flexion/abduction/external rotation between goniometric passive ROM and the Kinect ROM were 0.906/0.942/0.911, while those between active ROMs and the Kinect ROMs were 0.864/0.932/0.925. Cohen's kappa values were 0.88, 0.88, and 1.0 with the cutoff values in the order above. Measurements of the shoulder ROM using Kinect show excellent agreement with those taken using a goniometer. These results indicate that the Kinect can be used to measure shoulder ROM and to diagnose AC as an alternative to goniometer.

Quantification of Lumbar Stability During Wall Plank-and-Roll Activity Using Inertial Sensors.

OBJECTIVE: To develop a simple method of quantifying dynamic lumbar stability by evaluating postural changes of the lumbar spine during a wall plank-and-roll (WPR) activity while maintaining maximal trunk rigidity. DESIGN: A descriptive, exploratory research with a convenience sample. SETTING: A biomechanics laboratory of a tertiary university hospital. PARTICIPANTS: Sixteen healthy young subjects (8 men and 8 women; 30.7 ± 6.8 years old) and 3 patients (2 men 46 and 50 years old; 1 woman 54 years old) with low back pain (LBP). METHODS: The subjects performed the WPR activity with 2 inertial sensors attached on the thoracic spine and sacrum. Relative angles between the sensors were calculated to characterize lumbar posture in 3 anatomical planes: axial twist (AT), kyphosis-lordosis (KL), or lateral bending (LB). Isokinetic truncal flexion and extension power were measured. MAIN OUTCOME MEASURES: AT, KL, and LB were compared between the initial plank and maximal roll positions. Angular excursions were compared between males and females and between rolling sides, and tested for correlation with isokinetic truncal muscle power. Patterns and consistencies of the lumbar postural changes were determined. Lumbar postural changes of each patient were examined in the aspects of pattern and excursion, considering those from the healthy subjects as reference. RESULTS: AT, KL, and LB were significantly changed from the initial plank to the maximal roll position (P < .01); that is, the thoracic spine rotated further, lumbar lordosis increased, and the thoracic spine was bent away from the wall by 6.9° ± 12.0°, 9.5° ± 6.5°, and 7.9° ± 4.9°, respectively. The patterns and amounts of lumbar postural changes were not significantly different between the rolling sides or between male and female participants, except that the excursion in AT was larger on the dominant rolling side. The excursions were not related to isokinetic truncal muscle power. The 3 LBP patients showed varied deviations in pattern and excursion from the average of the healthy subjects. CONCLUSIONS: Certain amounts and patterns of lumbar postural changes were observed in healthy young subjects, with no significant variations based on gender, rolling side, or truncal muscle power. Application of the evaluation on LBP patients revealed prominent deviations from the healthy postural changes, suggesting potential clinical applicability. Therefore, with appropriate development and case stratification, we believe that the quantification of lumbar postural changes during WPR activity can be used to assess dynamic lumbar stability in clinical practice.

A grip force model for the da Vinci end-effector to predict a compensation force.

A torque transfer system (TTS) that measures grip forces is developed to resolve a potential drawback of the current da Vinci robot system whose grip forces vary according to the different postures of its EndoWrist. A preliminary model of EndoWrist Inner Mechanism Model (EIMM) is also developed and validated with real grip force measurements. EndoWrist's grip forces, posture angles, and transferred torque are measured by using TTS. The mean measured grip forces of three different EndoWrist for 27 different postures were very diverse. The EndoWrist exerted different grip forces, with a minimum of 1.84-times more and a maximum of 3.37-times more in specific posture even if the surgeon exerted the same amount of force. Using the posture angles as input and the grip forces as output, the EIMM is constructed. Then, expected grip force values obtained from EIMM are compared with actual measurements of da Vinci EndoWrist to validate the proposed model. From these results, surgeons will be beneficial with the understandings of actual grip force being applied to tissue and mechanical properties of robotic system. The EIMM could provide a baseline in designing a force-feedback system for surgical robot. These are significantly important to prevent serious injury by maintaining a proper force to tissue.

A study on the development of a robot-assisted automatic laser hair removal system.

UNLABELLED: Abstract Background and Objective: The robot-assisted automatic laser hair removal (LHR) system is developed to automatically detect any arbitrary shape of the desired LHR treatment area and to provide uniform laser irradiation to the designated skin area. METHODS: For uniform delivery of laser energy, a unit of a commercial LHR device, a laser distance sensor, and a high-resolution webcam are attached at the six axis industrial robot's end-effector, which can be easily controlled using a graphical user interface (GUI). During the treatment, the system provides real-time treatment progress as well as the total number of "pick and place" automatically. RESULTS: During the test, it was demonstrated that the arbitrary shapes were detected, and that the laser was delivered uniformly. The localization error test and the area-per-spot test produced satisfactory outcome averages of 1.04 mm error and 38.22 mm(2)/spot, respectively. CONCLUSIONS: RESULTS showed that the system successfully demonstrated accuracy and effectiveness. The proposed system is expected to become a promising device in LHR treatment.

Pneumatic-type surgical robot end-effector for laparoscopic surgical-operation-by-wire.

BACKGROUND: Although minimally invasive surgery (MIS) affords several advantages compared to conventional open surgery, robotic MIS systems still have many limitations. One of the limitations is the non-uniform gripping force due to mechanical strings of the existing systems. To overcome this limitation, a surgical instrument with a pneumatic gripping system consisting of a compressor, catheter balloon, micro motor, and other parts is developed. METHOD: This study aims to implement a surgical instrument with a pneumatic gripping system and pitching/yawing joints using micro motors and without mechanical strings based on the surgical-operation-by-wire (SOBW) concept. A 6-axis external arm for increasing degrees of freedom (DOFs) is integrated with the surgical instrument using LabVIEW® for laparoscopic procedures. The gripping force is measured over a wide range of pressures and compared with the simulated ideal step function. Furthermore, a kinematic analysis is conducted. To validate and evaluate the system's clinical applicability, a simple peg task experiment and workspace identification experiment are performed with five novice volunteers using the fundamentals of laparoscopic surgery (FLS) board kit. The master interface of the proposed system employs the hands-on-throttle-and-stick (HOTAS) controller used in aerospace engineering. To develop an improved HOTAS (iHOTAS) controller, 6-axis force/torque sensor was integrated in the special housing. RESULTS: The mean gripping force (after 1,000 repetitions) at a pressure of 0.3 MPa was measured to be 5.8 N. The reaction time was found to be 0.4 s, which is almost real-time. All novice volunteers could complete the simple peg task within a mean time of 176 s, and none of them exceeded the 300 s cut-off time. The system's workspace was calculated to be 11,157.0 cm3. CONCLUSIONS: The proposed pneumatic gripping system provides a force consistent with that of other robotic MIS systems. It provides near real-time control. It is more durable than the existing other surgical robot systems. Its workspace is sufficient for clinical surgery. Therefore, the proposed system is expected to be widely used for laparoscopic robotic surgery. This research using iHOTAS will be applied to the tactile force feedback system for surgeon's safe operation.

Tool to visualize and evaluate operator proficiency in laser hair-removal treatments.

BACKGROUND: The uniform delivery of laser energy is particularly important for safe and effective laser hair removal (LHR) treatment. Although it is necessary to quantitatively assess the spatial distribution of the delivered laser, laser spots are difficult to trace owing to a lack of visual cues. This study proposes a novel preclinic tool to evaluate operator proficiency in LHR treatment and applies this tool to train novice operators and compare two different treatment techniques (sliding versus spot-by-spot). METHODS: A simulation bed is constructed to visualize the irradiated laser spots. Six novice operators are recruited to perform four sessions of simulation while changing the treatment techniques and the presence of feedback (sliding without feedback, sliding with feedback, spot-by-spot without feedback, and spot-by-spot with feedback). Laser distribution maps (LDMs) are reconstructed through a series of images processed from the recorded video for each simulation session. Then, an experienced dermatologist classifies the collected LDMs into three different performance groups, which are quantitatively analyzed in terms of four performance indices. RESULTS: The performance groups are characterized by using a combination of four proposed indices. The best-performing group exhibited the lowest amount of randomness in laser delivery and accurate estimation of mean spot distances. The training was only effective in the sliding treatment technique. After the training, omission errors decreased by 6.32% and better estimation of the mean spot distance of the actual size of the laser-emitting window was achieved. Gels required operators to be trained when the spot-by-spot technique was used, and imposed difficulties in maintaining regular laser delivery when the sliding technique was used. CONCLUSIONS: Because the proposed system is simple and highly affordable, it is expected to benefit many operators in clinics to train and maintain skilled performance in LHR treatment, which will eventually lead to accomplishing a uniform laser delivery for safe and effective LHR treatment.

Manikin-integrated digital measuring system for assessment of infant cardiopulmonary resuscitation techniques.

The process of cardiopulmonary resuscitation (CPR) involves various components that must be followed to deliver high quality of CPR. While the components commonly apply to CPR for all ages from infant to adult, there are several different suggestions for infant CPR such as two-thumb CPR and two-finger CPR. However, the comprehensive evaluation based on all these components has been difficult in the absence of proper evaluation tool. Here, we developed a new manikin-integrated, digital measuring system that objectively estimates overall performance of infant CPR by evaluating individual CPR components one by one including different hand placements. The system collects and analyzes data to present estimations in digital scores according to a new evaluation index constructed based on the previously verified one. The feasibility of the system was validated through simulations with beginners and experts in first aid, resulting in statistically significant differences between the two groups with the indication of specific weaknesses for each group which may provide a basis for creating customized CPR training strategy in compliance with the personal level. We believe that the system would become a valuable assessment tool not only for infant CPR but also for the CPR technique, in general, by reflecting every component in the evaluation.

Influence of the washing program on the blood processing performance of a continuous autotransfusion device.

The continuous autotransfusion system has been widely used in surgical operations. It is known that if oil is added to blood, and this mixture is then processed by an autotransfusion device, the added oil is removed and reinfusion of fat is prevented by the device. However, there is no detailed report on the influence of the particular washing program selected on the levels of blood components including blood fat after continuous autotransfusion using such a system. Fresh bovine blood samples were processed by a commercial continuous autotransfusion device using the "emergency," "quality," and "high-quality" programs, applied in random order. Complete blood count (CBC) and serum chemistry were analyzed to determine how the blood processing performance of the device changes with the washing program applied. There was no significant difference in the CBC results obtained with the three washing programs. Although all of the blood lipids in the processed blood were decreased compared to those in the blood before processing, the levels of triglyceride, phospholipid, and total cholesterol after processing via the emergency program were significantly higher than those present after processing via the quality and high-quality programs. Although the continuous autotransfusion device provided consistent hematocrit quality, the levels of some blood lipid components showed significant differences among the washing programs.

Development and evaluation of an automatic acne lesion detection program using digital image processing.

BACKGROUND/PURPOSE: Existing acne grading methods, which depend on overall impression, require a long training period and there is a high degree of variability among raters, including trained dermatologists. The use of lesion count provides fair reproducibility but the method is time consuming. New technologies in photographic equipment and software allow solutions to the problem of acne evaluation. This study was conducted to develop the automatic acne lesion program and evaluation of its usefulness. METHODS: We made the conditions to optimize characterization of acne lesions and developed the counting program. Twenty-five volunteers with acne lesions were enrolled. Automated lesion counting for five subtypes of acne (papule, nodule, pustule, whitehead comedone, and blackhead comedone) was performed with image processing. The usefulness of the automatic lesion count program was assessed by a comparison with manual counting performed by an expert dermatologist. RESULTS: In a comparison with manual counting performed by an expert dermatologist, the sensitivity and positive predictive value of the lesion-counting program was greater than 70% for papules, nodules, pustules, and whitehead comedo. In a comparison with manual counting, findings with the use of the lesion-counting program were well correlated for papules, nodules, pustules, and whitehead comedo (r > 0.9). CONCLUSION: Automatic lesion-counting program can be a useful tool for acne severity evaluation.