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Wataru Kawakami, Makoto Takahashi, Yoshitaka Iwamoto and Koichi Shinakoda

previous studies investigated kinematic behaviors of feet affected by hallux valgus using multisegment foot models. 6 , 14 , 15 However, these studies used multisegment foot models defined by the shank, rearfoot, forefoot, and hallux without definition of the midfoot. Furthermore, although several

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Ben Langley, Nick Knight and Stewart C. Morrison

dynamic foot motion and MTSS has received less attention within the literature. Traditional running injury paradigms link excessive rearfoot pronation with the development of running-related injuries 6 , 7 on the premise that increasing the magnitude or duration of pronation would lead to abnormal

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Dorsey S. Williams III, Irene S. McClay, Joseph Hamill and Thomas S. Buchanan

High- and low-arched feet have long been thought to function differently. The purpose of this study was to investigate the relationship between arch structure and lower extremity mechanics in runners with extreme pes planus and pes cavus. It was hypothesized that low-arched individuals would exhibit an increased rearfoot eversion excursion, eversion/tibial internal rotation ratio, and increased angular velocity in rearfoot eversion when compared to high-arched runners. In addition, it was hypothesized that high-arched runners would exhibit greater vertical loading rates. Twenty high-arched and 20 low-arched runners with histories of running-related injuries were included in this study. Low-arched runners were found to have increased rearfoot eversion excursion, eversion to tibial internal rotation ratio, and rearfoot eversion velocity. High-arched runners had increased vertical loading rate when compared to low-arched runners. These results suggest that arch structure is associated with specific lower extremity kinematics and kinetics. Differences in these parameters may subsequently lead to differences in injury patterns in high-arched and low-arched runners.

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Carrie A. Laughton, Irene McClay Davis and Joseph Hamill

The main purpose of this study was to investigate the effects of both strike pattern (forefoot vs. rearfoot strike pattern) and orthotic intervention on shock to the lower extremity. Semi-rigid orthotic devices were manufactured for 15 injury-free recreational runners. Tibial accelerometry, ground reaction force, and 3D kinematic data were collected on their right leg in four conditions: forefoot strike (FFS) and rearfoot strike (RFS) with and without orthotics. Two-way repeated-measures analysis of variance tests were used to assess the effects of strike pattern and orthotic intervention on tibial acceleration; angular excursions of the ankle and knee; ground reaction force (GRF) vertical and anteroposterior peaks and load rates; and ankle, knee, and leg stiffness. There was a significant increase in tibial acceleration for the FFS pattern compared to the RFS pattern. This may be explained in part by the significantly greater peak vertical GRF, peak anteroposterior GRF, anteroposterior GRF load rates, knee stiffness, and leg stiffness found in the FFS pattern compared to the RFS pattern. Tibial acceleration and rearfoot eversion excursions were similar between the orthotic and no-orthotic conditions. Knee flexion excursion and average GRF vertical load rates were significantly decreased while dorsiflexion excursion and knee stiffness were significantly increased in the orthotic condition. No significant interactions were found between strike pattern and orthotic condition for any variables assessed.

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Seth T. Strayer, Seyed Reza M. Moghaddam, Beth Gusenoff, Jeffrey Gusenoff and Kurt E. Beschorner

impact of insole design parameters on contact pressure distribution. Figure 1 —(A) Prototype PopSole ™ geometry. (B) Finite element model with prescribed boundary conditions. The objective of this study was to develop a 3-dimensional (3D) FE model simulating contact between the rearfoot and the insole

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Bart Van Gheluwe and Claire Madsen

Excessive rearfoot motion, especially in the frontal plane, is believed to be a major cause of overload injuries in running. The aim of this study was to determine the influence of fatigue on frontal rearfoot motion just before volitional abandonment during an exhaustive run on a treadmill. Rearfoot kinematics were recorded three-dimensionally and reconstructed in a frontal plane associated with the heel. Statistical analysis of the results suggested that exhaustion did not influence tibial varum substantially, except at first heel strike. However, maximal calcaneal eversion and subtalar pronation did increase significantly, while maximal pronation velocity accelerated to 100°/s more than at the start of the exhaustive run. Also, the results of this study suggest that the increase in rearfoot motion is directly affected by fatigue and not by a fatigue-induced increase in step length.

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Adrienne E. Hunt and Richard M. Smith

Three-dimensional ankle joint moments were calculated in two separate coordinate systems, from 18 healthy men during the stance phase of walking, and were then compared. The objective was to determine the extent of differences in the calculated moments between these two commonly used systems and their impact on interpretation. Video motion data were obtained using skin surface markers, and ground reaction force data were recorded from a force platform. Moments acting on the foot were calculated about three orthogonal axes, in a global coordinate system (GCS) and also in a segmental coordinate system (SCS). No differences were found for the sagittal moments. However, compared to the SCS, the GCS significantly (p < .001) overestimated the predominant invertor moment at midstance and until after heel rise. It also significantly (p < .05) underestimated the late stance evertor moment. This frontal plane discrepancy was attributed to sensitivity of the GCS to the degree of abduction of the foot. For the transverse plane, the abductor moment peaked earlier (p < .01) and was relatively smaller (p < .01) in the GCS. Variability in the transverse plane was greater for the SCS, and attributed to its sensitivity to the degree of rearfoot inversion. We conclude that the two coordinate systems result in different calculations of nonsagittal moments at the ankle joint during walking. We propose that the body-based SCS provides a more meaningful interpretation of function than the GCS and would be the preferred method in clinical research, for example where there is marked abduction of the foot.

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C. Collin Herb, Lisa Chinn, Jay Dicharry, Patrick O. McKeon, Joseph M. Hart and Jay Hertel

Chronic ankle instability (CAI) results in longstanding symptoms and subjective feelings of “giving way” following initial ankle sprain. Our purpose was to identify differences in joint coupling and variability between shank internal/external rotation and rearfoot inversion/eversion throughout the gait cycle of CAI subjects and healthy controls. Twenty-eight young adults participated (CAI, n = 15, control, n = 13). Kinematics were collected while walking and jogging on a treadmill. A vector coding method in which direction (θ) and magnitude of the angle-angle relationship and stride-to-stride variability (VCV) in shank-rearfoot coupling were calculated. In walking, the CAI group demonstrated lower θ, indicating a greater proportion of rearfoot-to-shank motion, compared with the control group in early and late swing. The CAI group had higher magnitude, indicating greater combined motion between the two segments, in early swing, but lower magnitude, indicating less combined motion, during late swing. The CAI group also had lower VCV measures, indicating less stride-to-stride variability during stance. In jogging, the CAI group had lower θ measures than the control group during stance and swing. Differences in shank-rearfoot coupling of the CAI group may be related to changes in sensorimotor control and lead to further instances of instability.

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Roberto Ferrandis, Ana-Cruz García, José Ramiro, Juan-Víctor Hoyos and Pedro Vera

In this paper the changes produced in the kinematics of the foot during running when the upper vamp design of the shoes is modified are studied. Ten marathon runners who presented overpronation were selected, and five prototypes of running shoes, incorporating several rearfoot control features, were specially designed for the study. The rear plane of the lower leg was filmed at high speed during treadmill running while subjects wore the prototypes. Variables referring to maximum angles of rearfoot eversion and torsion were found to be more sensitive to changes introduced in the sport shoes than variables corresponding to ranges of motion. Statistically significant differences were found between prototypes during the support phase in rearfoot motion and torsion. In general the prototypes that showed an increase in rearfoot control also showed a decrease in torsion.

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Michelle A Sandrey, Carole J Zebas and Joseph D Bast

Context:

Soccer is a sport that includes running in several different directions. For this reason, it is important for the shoe to control the motion of the foot.

Objective:

This study was undertaken to compare rear-foot motion in high school soccer players with excessive pronation under the experimental conditions of barefoot (BF), experimental shoe (ESS), experimental shoe with arch support (ESSAS), and the experimental shoe with pronated lacing technique (ESSPLT).

Design:

1 × 4 factorial.

Setting:

Biomechanics laboratory.

Patients or Other Participants:

20 male and female subjects with excessive pronation in both feet (N = 40) as determined by navicular height and arch index.

Interventions:

The subjects were filmed with a 2D Peak Performance video system as they ran a specified course. Rear-foot motion was determined by rear-foot angle measurements from the point of foot-fat to heel off.

Main Outcomes Measures:

There would be a difference with rear-foot motion between the three experimental conditions.

Results:

Results of the study indicated significant (P ≤ .05) differences between the conditions of BF and ESS, BF and ESSAS, BF and ESSPLT, and ESS and ESSPLT.

Conclusions:

In the experimental conditions, the shoe with the pronated lacing technique was superior in its effectiveness to control rear-foot motion.