A.J. van den Bogert

Effect of skin movement on the analysis of skeletal knee joint motion during running

It is not known how well skin markers represent the skeletal knee joint motion during running. Hence the purpose of this investigation was to compare the skin marker derived tibiofemoral motion with the skeletal tibiofemoral motion during running. In addition to skin markers attached to the shank and thigh, triads of reflective markers were attached to bone pins inserted into the tibia and femur. Three-dimensional kinematics of the stance phase of five running trials were recorded for three subjects using high-speed cine cameras (200 Hz). The knee motion was expressed in terms of Cardan angles calculated from both the external and skeletal markers. Good agreement was present between the skin and bone marker based knee flexion/extension. For abduction/adduction and internal/external knee rotation, the difference between skeletal and external motion was large compared to the amplitude of these motions. Average errors relative to the range of motion during running stance were 21% for flexion/extension, 63% for internal/external rotation, and 70% for abduction/adduction. The errors were highly subject dependent preventing the realization of a successful correction algorithm. It was concluded that knee rotations other than flexion/extension may be affected with substantial errors when using skin markers.

The influence of foot positioning on ankle sprains

The goal of this study was to examine the influence of changes in foot positioning at touch-down on ankle sprain occurrence. Muscle model driven computer simulations of 10 subjects performing the landing phase of a side-shuffle movement were performed. The relative subtalar joint and talocural joint angles at touchdown were varied, and each subject-specific simulation was exposed to a set of perturbed floor conditions. The touchdown subtalar joint angle was not found to have a considerable influence on sprain occurrence, while increased touchdown plantar flexion caused increased ankle sprain occurrences. Increased touchdown plantar flexion may be the mechanism which causes ankles with a history of ankle sprains to have an increased susceptibility to subsequent sprains. This finding may also reveal a mechanism by which taping of a sprained ankle or the application of an ankle brace leads to decreased ankle sprain susceptibility.

Development and Validation of a 3-D Model to Predict Knee Joint Loading During Dynamic Movement

The purpose of this study was to develop a subject-specific 3-D model of the lower extremity to predict neuromuscular control effects on 3-D knee joint loading during movements that can potentially cause injury to the anterior cruciate ligament (ACL) in the knee. The simulation consisted of a forward dynamic 3-D musculoskeletal model of the lower extremity, scaled to represent a specific subject. Inputs of the model were the initial position and velocity of the skeletal elements, and the muscle stimulation patterns. Outputs of the model were movement and ground reaction forces, as well as resultant 3-D forces and moments acting across the knee joint. An optimization method was established to find muscle stimulation patterns that best reproduced the subjects movement and ground reaction forces during a sidestepping task. The optimized model produced movements and forces that were generally within one standard deviation of the measured subject data. Resultant knee joint loading variables extracted from the optimized model were comparable to those reported in the literature. The ability of the model to successfully predict the subjects response to altered initial conditions was quantified and found acceptable for use of the model to investigate the effect of altered neuromuscular control on knee joint loading during sidestepping. Monte Carlo simulations (N = 100,000) using randomly perturbed initial kinematic conditions, based on the subjects variability, resulted in peak anterior force, valgus torque and internal torque values of 378 N, 94 Nm and 71 Nm, respectively, large enough to cause ACL rupture. We conclude that the procedures described in this paper were successful in creating valid simulations of normal movement, and in simulating injuries that are caused by perturbed neuromuscular control.

Effects of Foot Orthoses on Skeletal Motion During Running

OBJECTIVE To quantify the effects of medial foot orthoses on skeletal movements of the calcaneus and tibia during the stance phase in running. DESIGN Kinematic effects of medial foot orthoses (anterior, posterior, no support) were tested using skeletal (and shoe) markers at the calcaneus and tibia. BACKGROUND Previous studies using shoe and skin markers concluded that medially placed orthoses control/reduce foot eversion and tibial rotation. However, it is currently unknown if such orthoses also affect skeletal motion at the lower extremities. METHODS Intracortical Hofman pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Eversion (skeletal and shoe) and tibial rotation were calculated to study the foot orthoses effects. RESULTS Orthotic effects on eversion and tibial rotations were found to be small and unsystematic over all subjects. Differences between the subjects were significantly larger (p<0.01; up to 10 degrees ) than between the orthotic conditions (1-4 degrees ). Significant orthotic effects across subjects were found only for total internal tibial rotation; p<0.05). CONCLUSIONS This in vivo study showed that medially placed foot orthoses did not change tibiocalcaneal movement patterns substantially during the stance phase of running. RELEVANCE Orthoses may have only small kinematic effects on the calcaneus and tibia (measured with bone pins) as well as on the shoes (measured with shoe markers) during running of normal subjects. Present results showed that orthotic effects were subject specific and unsystematic across conditions. It is speculated that orthotic effects during the stance phase of running may be mechanical as well as proprioceptive.

Tibiofemoral and tibiocalcaneal motion during walking: external vs. skeletal markers

Abstract The purpose of this study was to determine the errors in knee (tibiofemoral) and ankle joint complex (AJC; tibiocalcaneal) rotations caused by the skin movement artefact. Intracortical bone pins were inserted into the femur, tibia, and calcaneus of five subjects. Marker triads were attached to these pins, and additionally, six skin markers to the thigh, six to the shank, and three to the shoe. For each subject three walking trials were filmed with three synchronized LOCAM cameras (50 Hz). Flexion/extension, ab/adduction, and longitudinal rotation at the tibiofemoral joint as well as plantar-/dorsiflexion, ab/adduction, and in/eversion at the AJC were calculated from both skin and bone markers during the stance phase of walking. The results showed that the errors in knee rotations were mainly caused by the thigh markers. Knee flexion/extension was generally well reflected with the use of skin markers (mean difference: 2.1°). The agreement between skin and bone marker based kinematics for ab/adduction and internal/external knee rotation ranged from good to virtually no agreement, and in some subjects, the errors exceeded the actual motion. The errors in AJC rotations were mainly caused by the markers on the shoe/foot segment. The tibiocalcaneal rotations were generally well reflected with external markers. However, tibiocalcaneal rotations derived from external markers typically exceeded the true bone motions. The results suggest that (a) knee rotations other than flexion/extension may be affected with substantial errors when using external markers, and (b) tibiocalcaneal rotations are generally well reflected with external markers, but amplitudes are overestimated.

Evaluation of a two dimensional analysis method as a screening and evaluation tool for anterior cruciate ligament injury

Background: Increased knee valgus predicts the risk of anterior cruciate ligament (ACL) injury, particularly in women. Reducing injury rates thus relies on detecting and continually evaluating people with relatively large valgus motions. Objectives: To examine the potential of a two dimensional (2D) video analysis method for screening for excessive valgus. Methods: Ten female and 10 male National Collegiate Athletic Association basketball players had three dimensional (3D) knee valgus and two dimensional (2D) frontal plane knee angle quantified during side step, side jump, and shuttle run tasks. 3D valgus was quantified from external marker coordinates using standard techniques, and 2D data were obtained from both the frontal plane projections of these coordinates (2D-Mot) and manual digitisation of digital video footage (2D-Cam). A root mean square (RMS) error was calculated between 2D-Mot and 2D-Cam data to evaluate the reliability of the latter. Correlations between 2D-Cam and 3D data (intersubject and intrasubject) were also conducted, and regression slope and r2 values obtained. Results: 2D-Cam and 2D-Mot data were consistent for side step (RMS  =  1.7°) and side jump (RMS  =  1.5°) movements. Between subjects, 2D-Cam and 3D data correlated well for the side step (r2  =  0.58) and side jump (r2  =  0.64). Within subjects, 2D-Cam and 3D data correlated moderately for the side step (r2  =  0.25 (0.19)) and side jump (r2  =  0.36 (0.27)). Conclusions: The 2D-Cam method can be used to screen for excessive valgus in elite basketball players, particularly for movements occurring primarily in the frontal plane. This method may also be a useful training evaluation tool when large reductions in dynamic valgus motions are required.

Tibiocalcaneal motion during running, measured with external and bone markers.

OBJECTIVE: The purpose of this study was to compare tibiocalcaneal motion during running based on skeletal markers with tibiocalcaneal motion based on external markers. DESIGN. IN VIVO: measurements of external and skeletal tibiocalcaneal kinematics. BACKGROUND: External (shoe, skin) markers are typically used to determine rearfoot kinematics. However, it is not known if such markers are able to provide a good representation of the skeletal (tibiocalcaneal) kinematics. METHODS: Bone pins were inserted into the tibia and calcaneus of five subjects. The 3-D motion of markers attached to bone pins as well as of external markers attached to the shank and shoe were determined during the stance phase of five running trials. Intersegmental motion was expressed in terms of Cardan angles (plantarflexion/dorsiflexion, abduction/adduction, inversion/eversion). RESULTS: It was found that the skeletal inversion/eversion, abduction/adduction, and plantarflexion/dorsiflexion motions were similar across the subjects. The shape of the tibiocalcaneal rotation curves based on external markers were similar to those based on bone markers. However, the rotations were generally overestimated when using external markers, e.g. the average maximal eversion motion calculated from external markers was 16.0 degrees whereas the skeletal maximal eversion motion was only 8.6 degrees. These discrepancies were mainly due to the relative movement between shoe markers and underlying calcaneus. CONCLUSIONS: External markers are only gross indicators of the skeletal tibiocalcaneal motion. The rotations derived from external shoe and shank markers typically overestimate the skeletal tibiocalcaneal kinematics. RELEVANCE: Quantitative results determined from external markers have to be used with caution. For tibiocalcaneal rotations, external markers may be used to show trends, but absolute values cannot be trusted.

The influence of orthotic devices and vastus medialis strength and timing on patellofemoral loads during running

OBJECTIVE To use a musculoskeletal model and simulation of running to examine: (1) the influence of two commonly prescribed treatments for patellofemoral pain (vastus medialis oblique strengthening and orthoses) and (2) the functional significance of timing differences between vastus medialis oblique and vastus lateralis on lateral patellofemoral joint loads. DESIGN A three-dimensional musculoskeletal model of the lower extremity was used to simulate running at 4 m/s. BACKGROUND Repetitive and excessive joint loading is often associated with overuse injuries that require clinical treatments to reduce pain and restore function. Affecting one in four runners, patellofemoral pain is one of the most common injuries in running. Although conservative treatments have been reported to successfully treat patellofemoral pain, the effectiveness is often based on subjective or empirical data, which have generated disagreement on the most effective treatment. METHODS Nine subject specific running simulations were generated and experiments were performed by applying the treatments and timing differences to the nominal simulations. RESULTS Both treatments significantly reduced the average patellofemoral joint load and the vastus medialis strengthening also significantly reduced the peak patellofemoral joint load. In addition, when the vastus medialis oblique timing was delayed and advanced relative to the vastus lateralis timing, a significant increase and decrease in the joint load was observed, respectively, during the loading response.Conclusions. Increasing vastus medialis oblique strength yielded more consistent results across subjects than the orthosis in reducing patellofemoral joint loads during running. The effect of orthoses was highly variable and sensitive to the individual subjects running mechanics. Vastus medialis oblique activation timing is an important determinant of lateral patellofemoral joint loading during the impact phase. RELEVANCE These findings indicate that a reduction in patellofemoral pain may be achieved through techniques that selectively increase the vastus medialis oblique strength. Therefore, future studies should be directed towards identifying such techniques. Additionally, the functional significance of timing differences between the vastus medialis oblique and vastus lateralis is an important consideration in patellofemoral pain treatment and orthoses may be beneficial for some patients depending on their running mechanics.

A method for numerical simulation of single limb ground contact events: Application to heel-toe running

Abstract The objective of this work was to develop a method to simulate single-limb ground contact events, which may be applied to study musculoskeletal injuries associated with such movements. To achieve this objective, a three-dimensional musculoskeletal model was developed consisting of the equations of motion for the musculoskeletal system, and models for the muscle force generation and ground contact elements. An optimization framework and a weighted least-squares objective function were presented that generated muscle stimulation patterns that optimally reproduced subject-specific movement data. Experimental data were collected from a single subject to provide initial conditions for the simulation and tracking data for the optimization. As an example application, a simulation of the stance phase of running was generated. The results showed that the average difference between the simulation and subjects ground reaction force and joint angle data was less than two inter-trial standard deviations. Further, there was good agreement between the models muscle excitation patterns and experimentally collected electromyography data. These results give confidence in the model to examine musculoskeletal loading during a variety of landing movements and to study the effects of various factors associated with injury. Limitations were examined and areas of improvement for the model were presented.

Effect of gender on lower extremity kinematics during rapid direction changes: an integrated analysis of three sports movements.

Anterior cruciate ligament (ACL) injury is a common sports injury, particularly in females. Gender differences in knee kinematics have been observed for specific movements, but there is limited information on how these findings relate to other joints and other movements. Here we present an integrated analysis of hip, knee and ankle kinematics across three movements linked to non-contact ACL injury. It was hypothesised that there are gender differences in lower extremity kinematics, which are consistent across sports movements. Ten female and ten male NCAA basketball players had three-dimensional hip, knee and ankle kinematics quantified during the stance phase of sidestep, sidejump and shuttle-run tasks. For each joint angle, initial value at contact, peak value and between-trial variability was obtained and submitted to a two-way mixed design ANOVA (gender and movement), with movement condition treated as a repeated measure. Females had higher peak knee valgus and lower peak hip and knee flexion, with the same gender differences also existing at the beginning of stance (p<0.05). Peak valgus measures were highly correlated between movements, but not to static valgus alignment. Kinematic differences demonstrated by females for the sports movements studied, and in particular knee valgus, may explain their increased risk of ACL injury. These differences appear to stem largely from subject-specific neuromuscular mechanisms across movements, suggesting that prevention via neuromuscular training is possible.