scholarly journals Measuring Clinically Relevant Knee Motions With A Self-Calibrated Wearable Sensor

2018 ◽  
Author(s):  
Todd J. Hullfish ◽  
Feini Qu ◽  
Brendan D. Stoeckl ◽  
Peter M. Gebhard ◽  
Robert L. Mauck ◽  
...  
Keyword(s):  
Motion Capture ◽  
Knee Flexion ◽  
Low Cost ◽  
Calibration Procedure ◽  
Knee Extension ◽  
Strongly Correlated ◽  
Wearable Sensor ◽  
Additional Equipment ◽  
Peak Knee ◽  
Rms Error

AbstractLow-cost sensors provide a unique opportunity to continuously monitor patient progress during rehabilitation; however, these sensors have yet to demonstrate the fidelity and lack the calibration paradigms necessary to be viable tools for clinical research. Therefore, the purpose of this study was to validate a low-cost wearable sensor that accurately measured peak knee extension during clinical exercises and needed no additional equipment for calibration. Knee flexion was quantified using a 9-axis motion sensor and directly compared to motion capture data. Peak extension values during seated knee extensions were accurate within 5 degrees across all subjects (RMS error: 2.6 degrees, P = 0.29) but less accurate during sit-to-stand exercises (RMS error: 16.6 degrees, P = 0.48). Knee flexion during gait strongly correlated (0.84 ≤ rxy ≤ 0.99) with motion capture measurements but demonstrated average errors of 10 degrees. This study demonstrated a low-cost sensor that satisfied our criteria: a simple calibration procedure resulting in accurate measures of joint function during clinical exercises, making it a feasible tool for continuous patient monitoring to guide regenerative rehabilitation.

scholarly journals Military Protein Intake Related to Strength and Fat Mass Independent of Energy Intake

2020 ◽  
Vol 185 (9-10) ◽  
pp. e1671-e1678
Author(s):  
Jeremy A Ross ◽  
D Travis Thomas ◽  
Joshua D Winters ◽  
Scott D Royer ◽  
Christopher J Halagarda ◽  
...  
Keyword(s):  
Energy Intake ◽  
Body Mass ◽  
Knee Flexion ◽  
Protein Intake ◽  
Performance Metrics ◽  
Knee Extension ◽  
Special Operations ◽  
Knee Extension Strength ◽  
Peak Knee ◽  
Flexion Strength

ABSTRACT Introduction Kinetic military units operate in austere training environments and deprivation not commonly experienced by competitive athletes. Nutritional strategies to protect against decrements in performance and potential injury risk may differ for these two groups. A cross sectional analysis was conducted to determine energy and macronutrient characteristics associated with performance metrics. Materials and Methods 78 male subjects (age: 28.4 ± 6.0 years, height: 178.3 ± 6.7 cm, mass: 84.3 ± 9.4 kg, 8.5 ± 5.8 years of service) assigned to Marine Corps Forces Special Operations Command completed a 1-day performance assessment. Body mass, lean body mass, fat mass (FM), aerobic capacity (VO2max), lactate inflection point (LT), anaerobic power, anaerobic capacity, knee flexion strength, knee extension strength, peak knee flexion strength, and peak knee extension strength outcome values were recorded. Dietary intake was collected using automated self-administered 24-hour dietary recall (ASA24). Performance assessment scores were compared with macronutrient intake and controlled for energy intake using analysis of covariance. Results Differences in knee flexion strength, knee extension strength, peak knee flexion strength, and peak knee extension strength were significant across low (LPRO), medium (MPRO), and high (HPRO) protein intake groups (p < 0.05) with LPRO performance metrics significantly lower than both MPRO and HPRO and MPRO significantly lower than HPRO. FM was significantly higher in LPRO than MPRO or HPRO (p < 0.05). Low carbohydrate intake (LCHO) was associated with greater body mass and FM compared with high (HCHO) (p < 0.05). There was no association between fat intake and any variable. Conclusions Increases in protein intake may have beneficial performance effects independent of total energy intake, while moderate increases in carbohydrate intake may not be sufficient to enhance physical performance in a special operations population.

Concurrent Tactile Feedback Provided by a Simple Device Increased Knee Flexion and Decreased Impact Ground Reaction Forces During Landing

2016 ◽  
Vol 32 (3) ◽  
pp. 248-253 ◽  
Author(s):  
Boyi Dai ◽  
Mitchell L. Stephenson ◽  
Samantha M. Ellis ◽  
Michael R. Donohue ◽  
Xiaopeng Ning ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Low Cost ◽  
Cruciate Ligament ◽  
Tactile Feedback ◽  
Simple Device ◽  
Ground Reaction Forces ◽  
Knee Valgus ◽  
Peak Knee ◽  
Reaction Forces ◽  
Anterior Cruciate

Increased knee flexion and decreased knee valgus angles and decreased impact ground reaction forces (GRF) are associated with decreased anterior cruciate ligament (ACL) loading during landing. The purpose of this study was to determine the effect of tactile feedback provided by a simple device on knee flexion and valgus angles and impact GRF during landing. Kinematic and kinetic data were collected when 28 participants performed baseline, training, and evaluation jump-landing trials. During the training trials, the device was placed on participants’ shanks so that participants received tactile feedback when they reached a peak knee flexion angle of a minimum of 100°. During the evaluation trials, participants were instructed to maintain the movement patterns as they learned from the training trials. Participants demonstrated significantly (P < .008) increased peak knee flexion angles, knee flexion range of motion during early landing (first 100 ms of landing) and stance time, decreased impact posterior and vertical GRF during early landing and jump height, and similar knee valgus angles during the evaluation trials compared with the baseline trials. Immediately following training with tactile feedback, participants demonstrated landing patterns associated with decreased ACL loading. This device may have advantages in application because it provides low-cost, independent, and real-time feedback.

A Compact Low Cost Wearable Sensor System for Quantitative Gait Measurement

2014 ◽  
Vol 627 ◽  
pp. 212-216
Author(s):  
Ming Gui Tan ◽  
Cheng Boon Leong ◽  
Jee Hou Ho ◽  
Hui Ting Goh ◽  
Hoon Kiat Ng
Keyword(s):  
Gait Analysis ◽  
Motion Capture ◽  
Vision System ◽  
Low Cost ◽  
Sensor System ◽  
Wearable Sensor ◽  
Gait Parameters ◽  
Emg Electrodes ◽  
3D Motion Capture ◽  
Quantitative Gait Analysis

The demand for quantitative gait analysis increases due to increasing number of neurological disorder patients. Conventional gait analysis tools such as 3D motion capture systemsare relatively expensive. Therefore, there is a need to develop a low cost sensor system to obtain the spatial temporal gait parameters without compromising too much on the accuracy. This paper describesthe development of a wearable low cost sensor system which consists ofrelatively less sensing elements with 2 accelerometers, 4 force sensitive resistors (FSR) and 2 EMG electrodes. Thesensor output was validated by a vision system and the relative error was less than 5% formost of the gait parameters measured.

Effects of Prophylactic Knee Bracing on Lower Limb Kinematics, Kinetics, and Energetics During Double-Leg Drop Landing at 2 Heights

2016 ◽  
Vol 44 (7) ◽  
pp. 1753-1761 ◽  
Author(s):  
Katie A. Ewing ◽  
Rezaul K. Begg ◽  
Mary P. Galea ◽  
Peter V.S. Lee
Keyword(s):  
Knee Flexion ◽  
Knee Extension ◽  
Flexion Angle ◽  
Initial Contact ◽  
Knee Brace ◽  
Acl Injuries ◽  
Negative Power ◽  
Peak Knee ◽  
Knee Braces ◽  
Biomechanical Factors

Background: Anterior cruciate ligament (ACL) injuries commonly occur during landing maneuvers. Prophylactic knee braces were introduced to reduce the risk of ACL injuries, but their effectiveness is debated. Hypotheses: We hypothesized that bracing would improve biomechanical factors previously related to the risk of ACL injuries, such as increased hip and knee flexion angles at initial contact and at peak vertical ground-reaction force (GRF), increased ankle plantar flexion angles at initial contact, decreased peak GRFs, and decreased peak knee extension moment. We also hypothesized that bracing would increase the negative power and work of the hip joint and would decrease the negative power and work of the knee and ankle joints. Study Design: Controlled laboratory study. Methods: Three-dimensional motion and force plate data were collected from 8 female and 7 male recreational athletes performing double-leg drop landings from 0.30 m and 0.60 m with and without a prophylactic knee brace. GRFs, joint angles, moments, power, and work were calculated for each athlete with and without a knee brace. Results: Prophylactic knee bracing increased the hip flexion angle at peak GRF by 5.56° ( P < .001), knee flexion angle at peak GRF by 4.75° ( P = .001), and peak hip extension moment by 0.44 N·m/kg ( P < .001). Bracing also increased the peak hip negative power by 4.89 W/kg ( P = .002) and hip negative work by 0.14 J/kg ( P = .001) but did not result in significant differences in the energetics of the knee and ankle. No differences in peak GRFs and peak knee extension moment were observed with bracing. Conclusion: The application of a prophylactic knee brace resulted in improvements in important biomechanical factors associated with the risk of ACL injuries. Clinical Relevance: Prophylactic knee braces may help reduce the risk of noncontact knee injuries in recreational and professional athletes while playing sports. Further studies should investigate different types of prophylactic knee braces in conjunction with existing training interventions so that the sports medicine community can better assess the effectiveness of prophylactic knee bracing.

scholarly journals Soft soled footwear has limited impact on toddler gait

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251175
Author(s):  
Cylie Williams ◽  
Jessica Kolic ◽  
Wen Wu ◽  
Kade Paterson
Keyword(s):  
Knee Flexion ◽  
Subtalar Joint ◽  
Clinical Importance ◽  
Knee Extension ◽  
Temporal Data ◽  
Range Of Movement ◽  
Camera System ◽  
Peak Knee ◽  
Flexion Extension ◽  
Quasi Experimental

The development of walking in young toddlers is an important motor milestone. Walking patterns can differ widely amongst toddlers, and are characterised by unique biomechanical strategies. This makes comparisons between newly walking toddler’s and older children’s walking difficult. Little is currently understood regarding the effects of footwear on the gait in newly walking toddlers. A quasi-experimental pre-post study design was used to assess whether spatiotemporal parameters of gait, and in-shoe foot and lower limb kinematics, differed when walking barefoot and in soft-soled footwear in newly walking toddlers. There were 18 toddlers recruited, with 14 undergoing testing. The GAITRite system collected spatial and temporal data. The Vicon camera system collected kinematic data. The testing conditions included barefoot and footwear. Footwear tested was a commercially available soft soled shoe (Bobux XPLORER). Data was extracted directly from the GAITRite system and analysed. Walking in footwear did not change spatial or temporal data, however there were small but significant decreases in hip adduction/abduction range of motion (mean difference (MD) = 1.79°, 95% CI = -3.51 to -0.07, p = 0.04), knee flexion (MD = -7.63°, 95% CI = 2.70 to 12.55, p = 0.01), and knee flexion/extension range of movement (MD = 6.25°, 95% CI = -10.49 to -2.01, p = 0.01), and an increase in subtalar joint eversion (MD = 2.85°, 95% CI = 5.29 to -0.41, p = 0.03). Effect sizes were small for hip and ankle range, peak knee extension, and subtalar joint ranges (d<0.49), medium for knee flexion/extension range (d = 0.75) and large for peak knee flexion (d = 0.87). The magnitude of kinematic changes with soft-soled footwear were small thus the clinical importance of these findings is uncertain. Future longitudinal studies are needed to develop recommendations regarding footwear for newly walking toddlers.

Obese Youth Demonstrate Altered Landing Knee Mechanics Unrelated to Lower-Extremity Peak Torque When Compared With Healthy Weight Youth

2020 ◽  
pp. 1-9
Author(s):  
Matthew S. Briggs ◽  
Claire Spech ◽  
Rachel King ◽  
Mike McNally ◽  
Matthew Paponetti ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Knee Flexion ◽  
Peak Torque ◽  
Knee Extension ◽  
Knee Flexion Angle ◽  
Healthy Weight ◽  
Knee Mechanics ◽  
Landing Mechanics ◽  
Peak Knee ◽  
Hip Extension

Obese (OB) youth demonstrate altered knee mechanics and worse lower-extremity performance compared with healthy weight (HW) youth. Our objectives were to compare sagittal plane knee landing mechanics between OB and HW youth and to examine the associations of knee and hip extension peak torque with landing mechanics in OB youth. Twenty-four OB and 24 age- and sex-matched HW youth participated. Peak torque was measured and normalized to leg lean mass. Peak knee flexion angle and peak internal knee extension moment were measured during a single-leg hop landing. Paired t tests, Pearson correlation coefficients, and Bonferroni corrections were used. OB youth demonstrated worse performance and lower knee extension (OB: 12.76 [1.38], HW: 14.03 [2.08], P = .03) and hip extension (OB: 8.59 [3.13], HW: 11.10 [2.89], P = .005) peak torque. Furthermore, OB youth demonstrated lower peak knee flexion angles (OB: 48.89 [45.41 to 52.37], HW: 56.07 [52.59 to 59.55], P = .02) and knee extension moments (OB: −1.73 [−1.89 to −1.57], HW: −2.21 [−2.37 to −2.05], P = .0001) during landing compared with HW youth. Peak torque measures were not correlated with peak knee flexion angle nor internal knee extension moment during landing in either group (P > .01). OB youth demonstrated altered landing mechanics compared with HW youth. However, no associations among peak torque measurements and knee landing mechanics were present.

scholarly journals Quadriceps Neuromuscular Function and Jump-Landing Sagittal-Plane Knee Biomechanics After Anterior Cruciate Ligament Reconstruction

2018 ◽  
Vol 53 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Sarah H. Ward ◽  
J. Troy Blackburn ◽  
Darin A. Padua ◽  
Laura E. Stanley ◽  
Matthew S. Harkey ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Sagittal Plane ◽  
Neuromuscular Function ◽  
Knee Extension ◽  
Spinal Reflex ◽  
Flexion Angle ◽  
Voluntary Activation ◽  
Knee Flexion Angle ◽  
Jump Landing ◽  
Peak Knee

Context:  Aberrant biomechanics may affect force attenuation at the knee during dynamic activities, potentially increasing the risk of sustaining a knee injury or hastening the development of osteoarthritis after anterior cruciate ligament reconstruction (ACLR). Impaired quadriceps neuromuscular function has been hypothesized to influence the development of aberrant biomechanics. Objective:  To determine the association between quadriceps neuromuscular function (strength, voluntary activation, and spinal-reflex and corticomotor excitability) and sagittal-plane knee biomechanics during jump landings in individuals with ACLR. Design:  Cross-sectional study. Setting:  Research laboratory. Patients or Other Participants:  Twenty-eight individuals with unilateral ACLR (7 men, 21 women; age = 22.4 ± 3.7 years, height = 1.69 ± 0.10 m, mass = 69.4 ± 10.1 kg, time postsurgery = 52 ± 42 months). Main Outcome Measure(s):  We quantified quadriceps spinal-reflex excitability via the Hoffmann reflex normalized to maximal muscle response (H : M ratio), corticomotor excitability via active motor threshold, strength as knee-extension maximal voluntary isometric contraction (MVIC), and voluntary activation using the central activation ratio (CAR). In a separate session, sagittal-plane kinetics (peak vertical ground reaction force [vGRF] and peak internal knee-extension moment) and kinematics (knee-flexion angle at initial contact, peak knee-flexion angle, and knee-flexion excursion) were collected during the loading phase of a jump-landing task. Separate bivariate associations were performed between the neuromuscular and biomechanical variables. Results:  In the ACLR limb, greater MVIC was associated with greater peak knee-flexion angle (r = 0.38, P = .045) and less peak vGRF (r = −0.41, P = .03). Greater CAR was associated with greater peak internal knee-extension moment (ρ = −0.38, P = .045), and greater H : M ratios were associated with greater peak vGRF (r = 0.45, P = .02). Conclusions:  Greater quadriceps MVIC and CAR may provide better energy attenuation during a jump-landing task. Individuals with greater peak vGRF in the ACLR limb possibly require greater spinal-reflex excitability to attenuate greater loading during dynamic movements.

Does Chronic Ankle Instability Influence Knee Biomechanics of Females during Inverted Surface Landings?

2018 ◽  
Vol 39 (13) ◽  
pp. 1009-1017 ◽  
Author(s):  
Yumeng Li ◽  
Jupil Ko ◽  
Marika Walker ◽  
Cathleen Brown ◽  
Julianne Schmidt ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Knee Flexion ◽  
Sagittal Plane ◽  
Ankle Instability ◽  
Knee Extension ◽  
Chronic Ankle Instability ◽  
Initial Contact ◽  
Knee Biomechanics ◽  
Peak Knee ◽  
Eccentric Work

AbstractThe primary purpose of the study was to determine whether atypical knee biomechanics are exhibited during landing on an inverted surface. A seven-camera motion analysis system and two force plates were used to collect lower extremity biomechanics from two groups of female participants: 21 subjects with chronic ankle instability (CAI) and 21 with pair-matched controls. Subjects performed ten landings onto inverted and flat platforms on the CAI/matched and non-test limbs, respectively. Knee and ankle joint angles, joint angular displacements, joint moments and eccentric work were calculated during the landing phase and/or at the initial contact. Paired t-tests were used to compare between-group differences (p<0.05). We observed that CAI group displayed a significantly increased knee flexion angle, knee flexion displacement, peak knee extension moment and internal rotation moment, and eccentric work in the sagittal plane, possibly due to altered ankle biomechanics. Participants with CAI employed some compensatory strategy to improve their ankle and postural stability during landing onto the tilted surface. The increased knee extension and internal rotation moments of CAI participants could potentially result in a greater ACL loading. In future studies, it may be worthwhile to measure or estimate the ACL loading to confirm whether CAI could relate to the mechanism of ACL injury.

scholarly journals Exploring the Effect of Temporal Aggregation on SCADA Data for Wind Turbine Prognosis Using a Normality Model

2021 ◽  
Vol 11 (14) ◽  
pp. 6405
Author(s):  
Pere Marti-Puig ◽  
Alejandro Bennásar-Sevillá ◽  
Alejandro Blanco-M. ◽  
Jordi Solé-Casals
Keyword(s):  
Wind Turbine ◽  
Low Cost ◽  
Wind Farms ◽  
Temporal Aggregation ◽  
Time Interval ◽  
Irreversible Loss ◽  
Loss Of Information ◽  
Statistical Measures ◽  
Maximum Value ◽  
Additional Equipment

Today, the use of SCADA data for predictive maintenance and forecasting of wind turbines in wind farms is gaining popularity due to the low cost of this solution compared to others that require the installation of additional equipment. SCADA data provides four statistical measures (mean, standard deviation, maximum value, and minimum value) of hundreds of wind turbine magnitudes, usually in a 5-min or 10-min interval. Several studies have analysed the loss of information associated with the reduction of information when using five minutes instead of four seconds as a sampling frequency, or when compressing a time series recorded at 5 min to 10 min, concluding that some, but not all, of these magnitudes are seriously affected. However, to our knowledge, there are no studies on increasing the time interval beyond 10 min to take these four statistical values, and how this aggregation affects prognosis models. Our work shows that, despite the irreversible loss of information that occurs in the first 5 min, increasing the time considered to take the four representative statistical values improves the performance of the predicted targets in normality models.

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