Objective classification and scoring of movement deficiencies in patients with anterior cruciate ligament reconstruction

Motion analysis systems are widely employed to identify movement deficiencies-e.g. patterns that potentially increase the risk of injury or inhibit performance. However, findings across studies are often conflicting in respect to what a movement deficiency is or the magnitude of association to a specific injury. This study tests the information content within movement data using a data driven framework that was taught to classify movement data into the classes: NORM, ACLOP and ACLNO OP, without the input of expert knowledge. The NORM class was presented by 62 subjects (124 NORM limbs), while 156 subjects with ACL reconstruction represented the ACLOP and ACLNO OP class (156 limbs each class). Movement data from jumping, hopping and change of direction exercises were examined, using a variety of machine learning techniques. A stratified shuffle split cross-validation was used to obtain a measure of expected accuracy for each step within the analysis. Classification accuracies (from best performing classifiers) ranged from 52 to 81%, using up to 5 features. The exercise with the highest classification accuracy was the double leg drop jump (DLDJ; 81%), the highest classification accuracy when considering only the NORM class was observed in the single leg hop (81%), while the DLDJ demonstrated the highest classification accuracy when considering only for the ACLOP and ACLNO OP class (84%). These classification accuracies demonstrate that biomechanical data contains valuable information and that it is possible to differentiate normal from rehabilitating movement patterns. Further, findings highlight that a few features contain most of the information, that it is important to seek to understand what a classification model has learned, that symmetry measures are important, that exercises capture different qualities and that not all subjects within a normative cohort utilise 'true' normative movement patterns (only 27 to 71%)

Can a single-legged squat provide insight into movement control and loading during dynamic sporting actions in athletic groin pain patients?

Context: Chronic athletic groin pain (AGP) is common in field sports and has been associated with abnormal movement control and loading of the hip and pelvis during play. A single-legged squat (SLS) is commonly used by clinicians to assess movement control but whether it can provide insight into control during more dynamic sporting movements in AGP patients is unclear. Objective: To determine the relationships between biomechanical measures in a SLS and these same measures in a single-legged drop landing, single-legged hurdle hop and a cutting manoeuvre in AGP patients. Design: Cross-sectional study. Setting: Biomechanics laboratory. Patients: Forty recreational field sports players diagnosed with AGP. Intervention: A biomechanical analysis of each individual’s SLS, drop-landing, hurdle hop and cut was undertaken. Main Outcome Measures: Hip, knee and pelvis angular displacement, and hip and knee peak moments. Pearson product moment correlations were used to examine relationships between SLS measures and equivalent measures in the other movements. Results: There were no significant correlations between any hip or pelvis measure in the SLS with these same measures in the drop landing, hurdle hop or cut (r range = 0.03 - 0.43, P > 0.05). Knee frontal and transverse plane angular displacement were related in the SLS and drop landing only, while knee moments were related in the SLS, drop-landing and hurdle hop (r range = 0.50 - 0.67, P < 0.05). Conclusion: For AGP patients, a SLS did not provide a meaningful insight into hip and pelvis control or loading during sporting movements that are associated with injury development. The usefulness of a SLS test in the assessment of movement control and loading in AGP patients is thus limited. The SLS provided a moderate insight into knee control while landing and therefore may be of use in the examination of knee injury risk

THE EFFECTS OF AN EXERCISE INTERVENTION ON THE BIOMECHANICS OF AN ATHLETIC GROIN PAIN COHORT DURING THE LATERAL HURDLE HOP

The purpose of this study was to determine the kinematic and kinetic variables that may be of importance in the investigation of athletic groin pain (AGP). This was achieved by examining the 3D kinematics and kinetics of 70 AGP patients, recorded during a lateral hurdle hop, pre and post a successful exercise rehabilitation program. Results from the Copenhagen Hip and Groin Outcome Score questionnaire demonstrated significant improvements in 5 out of the 6 subscales. Analysis of characterising phases was used to examine kinematic and kinetic changes. Multiple significant changes were identified in both angles at the pelvis, hip and thorax and moments at the hip. Findings of this study provide an insight into the kinematic and kinetic variables of importance in AGP

COMPARISON OF INDIVIDUAL MUSCLE CONTRIBUTIONS TO GROUND REACTION FORCES DURING JUMP AND CHANGE OF DIRECTION TESTING AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The purpose of this study was to identify the main muscle contributions across a battery of different tasks commonly used to evaluate an athlete’s readiness to return to sport after anterior cruciate ligament injury (ACL) and following ACL reconstruction. These injuries are mostly related to landing and change of direction movements and, due to its high incidence, efforts must be made to better understand the knee soft tissue mechanisms during these types of tasks. Data from a single athlete were analysed for this study. Scaled generic musculoskeletal models, consisting of 12 segments, 23 degrees of freedom and 92 musculotendon actuators were used in OpenSim. The quadriceps were the main contributors to ground reaction forces along the anterior/posterior direction, and, aided by the soleus and gastrocnemii, counteracted most of the effects applied by gravity along the vertical direction. The main contributors to the ground reaction forces during all the tasks are the same muscles that are intimately related to ACL loading, thus making these tasks useful for injury rehabilitation programs

CHANGES IN HIP FORCE VECTOR AFTER ATHLETIC GROIN PAIN REHABILITATION DURING A RUNNING CUT

The purpose of this study was to examine changes in hip force vectors after successful athletic groin pain rehabilitation. Forty athletes with athletic groin pain that underwent a rehabilitation intervention participated in this study. Hip force magnitude, direction and their combination were examined using a continuous waveform analysis. Hip posterior and medial force at the start and end of the movement decreased following rehabilitation, while superior forces increased (over most of the movement cycle). Findings suggest that athletes with groin pain benefit from a rehabilitation intervention that decreases posterior and medial hip joint forces

Supervised learning techniques and their ability to classify a change of direction task strategy using kinematic and kinetic features

This study examines the ability of commonly used supervised learning techniques to classify the execution of a maximum effort change of direction task into predefined movement pattern as well as the influence of fuzzy executions and the impact of selected features (e.g. peak knee flexion) towards classification accuracy. The experiment utilized kinematic and kinetic data from 323 male subjects with chronic athletic groin pain. All subjects undertook a biomechanical assessment and had been divided previously into 3 different movement strategies in an earlier paper. Examined supervised learning techniques were: a decision tree, an ensemble of decision trees, a discriminant analysis model, a naive Bayes classifier, a k-nearest-neighbour model, a multi-class model for support vector machines, a stepwise forward regression model, a neural network and a correlation approach. Performance (measured by comparing the predefined and classified movement pattern) was highest for the correlation approach (82 % - CI 81 to 83 %) and support vector machine (80 % - CI 79 to 80 %). The percentage of fuzzy observations within the data was between 15 and 25 %. The most informative features for classification were: hip flexion angle, ankle rotation angle, a flexion moment [ankle and hip] and thorax flexion. Findings of this study support the assumption that multiple patterns are used to execute a movement task and demonstrate that classification models can predict movement patterns with a high accuracy (83 %)

Fat quantification in MRI-defined lumbar muscles

Some studies suggest fat infiltration in the lumbar muscles (LM) is associated with lower back pain (LBP) in adults. Usually fat in MRI-defined lumbar muscles is qualitatively valuated by visual grading via a 3 point scale, whereas a quantitative continuous (0 - 100%) approach may provide a greater insight. In this paper, we propose a method to precisely quantify the fat content / infiltration in a user-defined region of the lumbar muscles, which may aid better diagnosis. The key steps are segmenting the region of interest (ROI) from the lumbar muscles, identifying the fatty regions in the segmented region based on the selected threshold and softness levels, computing the parameters (such as total and region-wise fat content percentage, total-cross sectional area (TCSA), functional cross- sectional area (FCSA)) and exporting the computations and associated patient information from the MRI, into a atabase. A standalone application using MATLAB R2010a was developed to perform the required computations along with an intuitive GUI

CHANGES IN THE BIOMECHANICS OF A REACTIVE CUTTING MANOEUVRE IN AN ATHLETIC GROIN PAIN COHORT FOLLOWING A SUCCESSFUL REHABILITATION INTERVENTION

Athletic groin pain (AGP) is prevalent in field sports that require rapid changes of direction. The purpose of this study was to investigate the kinetic and kinematic changes that occurred in an unplanned reactive cutting manoeuvre following a successful rehabilitation intervention. Kinematics and kinetics were analysed using statistical parametric mapping in 23 patients before and after an exercise intervention programme. Significant improvements were found in all subscales of the Copenhagen Hip and Groin Outcome Score and biomechanical changes were identified at the pelvis, knee and ankle. These findings provide insight into mechanical variables of potential importance in AGP as identified during a manoeuvre based on a common sporting task

An interactive segmentation tool for quantifying fat in lumbar muscles using axial lumbar-spine MRI

In this paper we present an interactive tool that can be used to quantify fat infiltration in lumbar muscles, which is useful in studying fat infiltration and lower back pain (LBP) in adults. Currently, a qualitative assessment by visual grading via a 5-point scale is used to study fat infiltration in lumbar muscles from an axial view of lumbar-spine MR Images. However, a quantitative approach (on a continuous scale of 0–100%) may provide a greater insight. In this paper, we propose a method to precisely quantify the fat deposition/infiltration in a user-defined region of the lumbar muscles, which may aid better diagnosis and analysis. The key steps are interactively segmenting the region of interest (ROI) from the lumbar muscles using the well known livewire technique, identifying fatty regions in the segmented region based on variable-selection of threshold and softness levels, automatically detecting the center of the spinal column and fragmenting the lumbar muscles into smaller regions with reference to the center of the spinal column, computing key parameters [such as total and region-wise fat content percentage, total-cross sectional area (TCSA) and functional cross-sectional area (FCSA)] and exporting the computations and associated patient information from the MRI, into a database. A standalone application using MATLAB R2014a was developed to perform the required computations along with an intuitive graphical user interface (GUI)