The anterior cruciate ligament (ACL) plays an important role in stabilizing translation and rotation of the tibia relative to the femur. Individuals with ACL deficiency usually demonstrate ...alterations in gait characteristics. Evidence indicates that walking speed, alterations in kinetics and kinematics on the ACL deficient limb, and inter-limb asymmetries between deficient and intact knees may contribute to poor long-term outcomes following ACL deficiency. They corrode function of the knee joint and put it at higher risk of degeneration. For the purpose of developing an automatic and highly accurate system for detection of ACL deficiency, this study investigated the classification capability of different dynamical features extracted from gait kinematic and kinetic signals when evaluating their impact on different classification models. A general feature extraction framework was proposed and various dynamical features, such as recurrence rate, determinism and entropy from the recurrence quantification analysis, fuzzy entropy, Teager-Kaiser energy feature and statistical analysis, were included. Different classification models, including support vector machine (SVM), K-nearest neighbor (KNN), naive Bayes (NB) classifier, decision tree (DT) classifier and ensemble learning based Adaboost (ELA) classifier, derived for discriminant analysis of multiple dynamical gait features were evaluated for a comparative study. The effectiveness of this strategy was verified using a dataset of knee, hip and ankle kinematic and kinetic waveforms from 43 patients with unilateral ACL deficiency. When evaluated with 2-fold, 10-fold and leave-one-out cross-validation styles, the highest classification accuracy for discriminating between groups of ACL deficient and contralateral ACL intact knees was reported to be 91.22
%
, 95.12
%
and 96.34
%
, respectively,by using the SVM classifier and the optimal feature set. For other four classifiers, KNN achieved the accuracy of 78.05
%
, 85.37
%
and 87.80
%
, respectively. NB achieved the accuracy of 57.56
%
, 60.98
%
and 61.22
%
, respectively. DT achieved the accuracy of 77.56
%
, 80.49
%
and 83.66
%
, respectively. ELA achieved the accuracy of 73.66
%
, 78.05
%
and 79.27
%
, respectively. Compared with other state-of-the-art methods, the results demonstrate superior performance and support the validity of the proposed method.
Background:
Anterior cruciate ligament (ACL) tear is a common injury in sports and often occurs during landing from a jump.
Purpose:
To synthesize the evidence on the effects of injury prevention ...programs (IPPs) on landing biomechanics as they relate to the ligament, quadriceps, trunk, and leg dominance theories associated with ACL injury risk.
Study Design:
Meta-analysis.
Methods:
Six electronic databases were searched for studies that investigated the effect of IPPs on landing task biomechanics. Prospective studies that reported landing biomechanics at baseline and post-IPP were included. Results from trunk, hip, and knee kinematics and kinetics related to the ACL injury theories were extracted, and meta-analyses were performed when possible.
Results:
The criteria were met by 28 studies with a total of 466 participants. Most studies evaluated young females, bilateral landing tasks, and recreational athletes, while most variables were related to the ligament and quadriceps dominance theories. An important predictor of ACL injury, peak knee abduction moment, decreased (P = .01) after the IPPs while other variables related to the ligament dominance theory did not change. Regarding the quadriceps dominance theory, after the IPPs, angles of hip flexion at initial contact (P = .009), peak hip flexion (P = .002), and peak knee flexion (P = .007) increased, while knee flexion at initial contact did not change (P = .18). Moreover, peak knee flexion moment decreased (P = .005) and peak vertical ground-reaction force did not change (P = .10).
Conclusion:
The exercises used in IPPs might have the potential to improve landing task biomechanics related to the quadriceps dominance theory, especially increasing peak knee and hip flexion angles. Importantly, peak knee abduction moment decreased, which indicates that IPPs influence a desired movement strategy to help athletes overcome dangerous ligament dominance loads arising from lack of frontal plane control during dynamic tasks. The lack of findings for some biomechanical variables suggests that future IPPs may be enhanced by targeting participants’ baseline profile deficits, highlighting the need to deliver an individualized and task-specific IPP.
Low back pain is one of the most prevalent musculoskeletal conditions and the highest contributor to disability in the world. It is characterized by frequent relapses leading to additional ...care-seeking. Engagement in leisure physical activity is associated with lower recurrences and better prognosis and potentially reduced care-seeking. Our aim was to investigate the feasibility and preliminary efficacy of a patient-centred physical activity intervention, supported by health coaching and mobile health, to reduce care-seeking, pain and disability in patients with chronic low back pain after treatment discharge.
We conducted a pilot randomised controlled trial with blinded outcome assessment. Sixty-eight participants were recruited from four public outpatient physiotherapy departments and the general community in Sydney. The intervention group received a physical activity information booklet, plus one face-to-face and 12 telephone-based health coaching sessions. The intervention was supported by an internet-based application and an activity tracker (Fitbit). Control group (standard care) received the physical activity information booklet and advice to stay active. Feasibility measures included recruitment rate, intervention compliance, data completeness, and participant satisfaction. Primary outcomes were care-seeking, pain levels and activity limitation. Outcomes were assessed at baseline, 6-month follow-up and weekly for 6 months.
Ninety potential participants were invited over 15 months, with 68 agreeing to take part (75%). Overall, 903 weekly questionnaires were answered by participants from a total of 1107 sent (89%). Participants were largely satisfied with the intervention (mean = 8.7 out of 10 on satisfaction scale). Intervention group participants had a 38% reduced rate of care-seeking (Incidence Rate Ratio (IRR): 0.62, 95% CI: 0.32 to 1.18, p = 0.14, using multilevel mixed-effects Poisson regression analysis) compared to standard care, although none of the estimates was statistically significant. No between groups differences were found for pain levels or activity limitation.
The health coaching physical activity approach trialed here is feasible and well accepted by participants and may reduce care-seeking in patients with low back pain after treatment discharge, although further evaluation with an adequately powered trial is needed.
Australian and New Zealand Trial Registry ACTRN12615000189527 . Registered prospectively on 26-02-2015.
Background:
Despite knee extensor and flexor strength reportedly being associated with injury risk, including rupture of the anterior cruciate ligament in girls, there is limited evidence for the ...longitudinal changes in lower extremity strength.
Purpose:
To investigate the sex-specific relationship with longitudinal changes of knee extensor and flexor strength associated with maturation.
Study design:
Cohort study; Level of evidence, 2.
Methods:
Adolescent boys and girls (N = 257; 208 adolsecent girls) participating in high school basketball, volleyball, and soccer were assessed longitudinally in at least 2 different pubertal stages. Pubertal status (prepubertal, pubertal, and postpubertal) was determined with the modified Pubertal Maturation Observation Scale questionnaire. After a warm-up of 5 submaximal repetitions, participants were tested for concentric peak isokinetic strength for knee extension and flexion at 300 deg/s over 10 repetitions and normalized to body weight. Linear mixed models were used to test for the effect of pubertal stage, sex, and their interaction.
Results:
Significant interactions were identified that indicated different maturational trajectories for knee muscle strength for adolescent boys and girls, particularly between prepubertal and pubertal stages, in which boys demonstrated greater mass normalized knee extensor increases than girls (right, +12% vs +5%; left, +13% vs +7%; P < .001). For knee flexors, boys demonstrated increased strength, while girls demonstrated decreased relative knee flexor strength (right, +4% vs −1%, P = .03; left, +3 vs −3%, P = .009).
Conclusion:
The findings of this study support a differential effect of sex and maturation on important knee strength outcomes that may have implications for knee injury reduction, particularly in adolescent girls as they mature.
Abstract Background Telehealth has emerged as a potential alternative to deliver interventions for low back pain (LBP), however its effectiveness has not been investigated. Purpose The aim of this ...review was to evaluate whether interventions delivered by telehealth improve pain, disability, function, and quality of life in non-specific LBP. Study Design Systematic review with meta-analysis Methods Seven databases were searched from the earliest records to August 2015. Eligible studies were randomized controlled trials that investigated the effectiveness of telehealth-based interventions, solo or in combination with other interventions, for non-specific LBP compared to a control group. Trials deemed clinically homogeneous were grouped in meta-analyses. Results Eleven studies were included (N = 2280). In chronic LBP, telehealth interventions had no significant effect on pain at short four trials; 1,089 participants; weighted mean difference (WMD) -2.61 points; 95% CI: -5.23 to 0.01 or medium-term follow-up (two trials; 441 participants; WMD: -0.94 points; 95% CI: -6.71 to 4.84) compared to a control group. Similarly, there was no significant effect for disability. Results from three individual trials showed that telehealth was superior to a control intervention for improving quality of life. Interventions combining telehealth and usual care were more beneficial than usual care alone in people with recent onset of LBP symptoms. Conclusion There is moderate-quality evidence that current telehealth interventions, alone, are not more effective than minimal interventions for reducing pain and disability in chronic LBP. To date, modern telehealth media (e.g. apps) and telehealth as an adjunct to usual care remain understudied.
The aim of this study is to develop a new pattern recognition-based method to model and discriminate gait dynamics disparity between anterior cruciate ligament (ACL) deficient (ACL-D) knee and ...contralateral ACL-intact (ACL-I) knee in patients with unilateral ACL deficiency by using kinematic features and neural networks. Thereby the capabilities of these features to detect the presence of injury can be assessed. The proposed method consists of two stages. In the first (training) stage, gait analysis is performed. A two-dimensional five-link biped model used for imitating human gait locomotion is employed to demonstrate that functions containing kinematic data of lower extremities, including knee and hip flexion/extension angles and angular velocities, characterize the gait system dynamics. Knee angle-hip angle cyclograms, knee and hip angle-angular velocity phase portraits visually demonstrate the significant disparity of gait dynamics between the lower extremities of patients with unilateral ACL deficiency. Gait dynamics underlying gait patterns of ACL-D and ACL-I knees are locally accurately modeled and approximated by radial basis function (RBF) neural networks via deterministic learning theory. The derived knowledge of approximated gait dynamics is preserved in constant RBF networks. In the second (classification) stage, a bank of dynamical estimators is constructed using the preserved constant RBF networks to represent the learned training gait patterns. By comparing the set of estimators with a test gait pattern, the generated average
L
1
norms of errors are taken as the disparity and classification measure between the training and test gait patterns to differentiate between ACL-D and ACL-I knees. Finally, experiments are carried out on forty-three patients to assess the effectiveness of the proposed method. By using the leave-one-out cross-validation style under normal and fast walking speed conditions, the correct classification rates for discriminating between ACL-D and ACL-I knees are reported to be 95.61
%
and 93.03
%
, respectively. Compared with other state-of-the-art methods, the results demonstrate that gait alterations in the presence of chronic ACL deficiency can be visualized through cyclograms and phase portraits, and can be detected with superior performance.
The anterior cruciate ligament (ACL) possesses the function of stabilizing the knee joint through limiting anterior tibial translation and controlling tibial rotation. Patients with unilateral ACL ...deficiency often demonstrate alterations of knee kinematics, kinetics and gait patterns in the deficient side in comparison to the unaffected contralateral side. This also leads to the early onset of osteoarthritis. In order to detect and monitor the progression of ACL deficiency over time, various classification approaches using spatiotemporal gait variables have been presented. In this study we propose a novel method for classifying gait patterns between ACL-deficient (ACLD) knee and unaffected contralateral ACL-intact (ACLI) knee based upon gait system dynamics, intrinsic time-scale decomposition (ITD) and neural networks. First, human leg is modeled as a double-pendulum to imitate and simplify the human walking. Since the lower extremities act as a kinetic chain during dynamic tasks, control of the hip joint will interact with knee motion. Related gait kinematic parameters including knee and hip joint angle and angular velocity are decomposed into a series of proper rotation components (PRCs) and a baseline signal by using the ITD method. The first PRCs of knee and hip joint angle and angular velocity are extracted, which contain most of the kinematic signals’ vibration energy and are considered to be the predominant PRCs. Third, neural networks are then used as the classifier with feature vectors as the input to distinguish between ACLD and ACLI knees based on the difference of gait system dynamics between the two groups. Finally, experiments are carried out on forty-three patients to assess the effectiveness of the proposed method. By using the leave-one-out cross-validation style under normal and fast walking speed conditions, the correct classification rates are reported to be
95.12
%
and
93.28
%
, respectively. In comparison to other state-of-the-art methods, the results demonstrate superior performance and the proposed method may serve as a potential assistant tool for the automatic detection of ACL deficiency in the clinical application.
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