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Abstract: The purpose of this study was to quantify isolated coupling mechanisms of calcaneal adduction/abduction and calcaneal eversion/inversion to proximal bones in vitro. The in vitro approach is necessary because in vivo both movements appear together, making it impossible to determine the extent of their individual contribution to overall ankle joint coupling. Eight fresh frozen foot‐leg specimens were tested. Data describing bone orientation and coupling mechanisms between segments were obtained using bone pin marker triads. The bone movement was described in a global coordinate system to examine the coupling between the calcaneus, talus and tibia. The strength of coupling was determined by means of the slope of a linear least squares fit to an angle–angle plot. The coupling coefficients in the present study indicate that not only calcaneal eversion/inversion (coupling coefficient: 0.68 ± 0.15) but to an even greater extent calcaneal adduction/abduction (coupling coefficient: 0.99 ± 0.10) was transferred into talus and tibial rotation, highlighting the relevance of calcaneal adduction for the overall ankle joint coupling. The results of this study present the possibility that controlling calcaneal adduction/abduction can affect talus and tibial rotation and therefore the possible genesis of overuse knee injuries. [ABSTRACT FROM AUTHOR]

The free moment is considered an important variable during running in lower extremity transverse plane loading of the support leg. The effect of current footwear technology on free moment application has not been widely studied despite evidence that greater free moment amplitudes may be related to common lower extremity overuse injuries. Therefore, the purpose of this study was to determine the effect of current running shoe types on the free moment application in running and to identify which design features specifically influence free moment waveforms. The free moments and lower extremity kinematics of 103 recreational runners were collected when running at 3.5 m/s using force plates embedded in the ground. Six conditions were analysed, ranging from minimalistic to motion-control footwear. Runners were classified into three groups of different free moment pattern using functional principal component and cluster analysis techniques. The results revealed that the free moment application can be affected by footwear technologies used in modern running shoes. Nonetheless, the free moment application was influenced to a greater extent by the overall running technique highlighted by the greater effect sizes for pattern membership compared to footwear effects. Footwear may affect the free moment application as a function of its torsional flexibility and to a lesser extent by means of motion-control features. Future studies should address the effect of footwear design features (such as shoe-mass and traction) on free moment application in greater detail to improve the running style with respect to injury prevention and performance enhancement. [ABSTRACT FROM PUBLISHER]

The aim of this study was to use bone-anchored markers to determine the bone movement of calcaneal adduction, eversion and tibial rotation in a global coordinate system and to describe the relationship of calcaneal adduction to tibial rotation. Furthermore, the amount of overall intra-foot motion in the transverse plane (metatarsal I relative to calcaneus) and its relationship to calcaneal adduction were quantified. Three male participants were assessed during slow running. A 10-camera motion analysis system was used for kinematic data capture of global bone orientations in 3D space for all bones of the foot and ankle complex. For the description of intrinsic articulations within the foot, the skeletal motion relative to the adjacent proximal segment in the transverse plane was calculated. Furthermore, the time of occurrence of maximum values was determined. The findings showed that calcaneal adduction of all participants amounted to 7.8 ± 4.8°, which exceeded the magnitude of calcaneal eversion (4.7 ± 3.1°). Although the inter-participant variability was high, considerable overall intra-foot motion in the transverse plane of the metatarsal I relative to the calcaneus was found to be 4.7 ± 4.6° and could be qualitatively related to calcaneal adduction. The present data provide evidence that next to calcaneal eversion, calcaneal adduction seems related to tibial rotation. Furthermore, overall intra-foot motion in the transverse plane seems related to calcaneal adduction. Controlling calcaneal adduction and overall intra-foot motion in the transverse plane may be a mechanism to control excessive tibial rotation in runners who suffer from overuse knee injuries. These findings could be used to provide an additional approach for future motion-control footwear design to control rearfoot adduction or overall within-foot motion. [ABSTRACT FROM PUBLISHER]

Objective: To quantify the magnitude of global rearfoot motion, in particular, rearfoot adduction and to investigate its relationship to tibial rotation.Design: One hundred and four participants ran barefoot on an Ethylene Vinyl Acetate (EVA) foam. Global range of motion values for the shank, rearfoot and medial metatarsal segment as well as foot motion within the transverse plane were determined using an optoelectric motion capture system. Relationships between parameters were assessed using partial correlation analysis.Results: Global rearfoot adduction amounts to 6.1° (±2.7). Furthermore global rearfoot adduction and rearfoot eversion were significantly related to internal tibial rotation (partial correlation: r=0.37, p<0.001 and r=-0.24, p=0.015, respectively). Furthermore, a strong relationship between rearfoot adduction and transverse within foot motion (r=-0.65, p<0.001) was found.Conclusion: Next to rearfoot eversion, rearfoot adduction may be also important to the understanding of ankle joint coupling. Controlling rearfoot adduction and transverse within foot motion may be a mechanism to control excessive tibial rotation. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to identify kinetic responses to running on mediolaterally elevated (cross-sloped) running surfaces. Ground reaction forces (GRFs), GRF lever arms and joint moment characteristics of 19 male runners were analyzed when running at 3.5 m/s on a custom-made, tiltable runway. Tilt angles of 3° and 6° for medial and lateral elevation were analyzed using a 10 camera Vicon Nexus system and a force platform. The point of force application of the GRF showed a systematic shift in the order of 1-1.5 cm to either the lateral or medial aspect of the foot for lateral or medial inclinations, respectively. Consequently, the strongest significant effects of tilt orientation and level on joint kinetics and ground reaction force lever arms were identified at the ankle, knee and hip joint in the frontal plane of movement. External eversion moments at the ankle were significantly increased by 35% for 6° of lateral elevation and decreased by 16% for 6° of medial elevation. Altering the cross-slope of the running surface changed the pattern of ankle joint moments in the transversal plane. Effect sizes were on average larger for laterally elevated conditions, indicating a higher sensitivity of kinetic parameters to this kind of surface tilt. These alterations in joint kinetics should be considered in the choice of the running environment, especially for specific risk groups, like runners in rehabilitation processes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the relationship between free moment (FM) characteristics, joint mechanics and injury risk, in order to evaluate the potential of the FM as a variable for runner classification into functional groups with similar footwear demands. Lower extremity joint mechanics, ground reaction forces and the FM of 222 male and female injury free runners were analysed using an optoelectric motion capture system and a force plate while running at 3.5 m/s. During a follow-up period of 6 months, runners were reporting any running-related injuries to an experienced orthopaedist. Different FM patterns could be extracted using functional principal component analysis (FPCA). The first two eigenfunctions derived from FPCA were able to predict about 87% of the variance in the data-set and could be related to the two main functions of FM application in straight running -- transversal plane whole body oscillation control and compensation of insufficient transversal moment cancellation. FM patterns differed with respect to lower extremity joint moments and joint kinematics, mostly in the transversal and frontal plane of motion. Runners suffering from patellofemoral pain syndrome showed FM patterns with distinct external rotation components and differed from their matching controls, even though the number of runners, who suffered from injuries were too low to allow valid inferences. In conclusion, it seems that the FM could be useful in the classification of runners into functional groups as it possesses a considerable inter-subject variability, a relationship to the mechanical demands put on lower extremity joints and potentially to injury risk, while being comparably easy to measure. [ABSTRACT FROM AUTHOR]

Only a few studies have measured the movement of the calcaneus inside the shoe during running, and those that have done so have focused on the frontal plane of motion. This study's objective was to determine the three-dimensional (3D) movement of the calcaneus inside the shoe during running. A secondary objective was to determine if calcaneus movement differs between neutral and support shoes. Ten participants ran at 3.5 m/s in two shoes: a neutral and a support shoe. Right rearfoot kinematics were measured using reflective markers affixed to the shoe heel counter and to the skin of the rearfoot inside the shoe. 3D segment angle ranges of motion were calculated and compared across the shoe heel and calcaneus conditions, and across the two shoe conditions. The movement of the calcaneus compared to the shoe heel was not different in the frontal plane, but was significantly different in the transverse plane, with the calcaneus adducting by 4° more than the shoe heel. The calcaneus also moved significantly more than the shoe in the sagittal plane. Results were similar across the shoe conditions except in the frontal plane where less rearfoot eversion was measured in the support compared to the neutral shoe. The results from this study highlight an opportunity for the development of footwear technologies that can guide calcaneal adduction. Additionally, markers on the shoe heel counter may be appropriate for measuring motion of the foot inside the shoe in the frontal plane, but not the transverse plane. [ABSTRACT FROM PUBLISHER]