Intrinsic foot motion measured in vivo during barefoot running

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Journal of Biomechanics 2006, Vol. 39 (Suppl 1)

Oral Presentations

5476 We, 09:00-09:15 (P28) Intrinsic foot motion measured in vivo during barefoot running A. Arndt 1,2, P. Wolf 3, C. Nester 4, A. Liu 4, R. Jones 4, D. Howard 4, A. Stacofl~, P. Lundgren 1, A. Lundberg 1. 1Karollnska University Hospital, Stockholm,

Sweden, 2University College of Physical Education and Sport, Stockholm, Sweden, 3Laboratory of Biomechanics, ETH, ZEtrich, Switzerland, 4Centre for Rehabilitation & Human Performance, University of Salford, Salford, England, UK Knowledge of the natural range of motion of individual skeletal segments in the foot during running is necessary for the construction of appropriate stability parameters in athletic footwear. Globally restricting intrinsic motion of the foot may result in non-physiological stresses on specific foot bones or at more proximal sites such as the ankle ligaments. This study presents data on relative three-dimensional motion of individual foot segments, measured in vive with the use of reflective marker arrays attached to intracortical pins inserted in the tibia, talus, calcaneus, cuboid and navicular under local anaesthetic. Data were collected using a 10-camera optoelectric system (Qualysis, Sweden). Mean data for one subject (9 overground barefoot running trials, mean velocity: 2.2 m/s) are presented in table 1. The trials were reproducible (maximum 95% CI across all parameters: 2.3°). Table 1. Mean ranges of motion (o) in specific joints. Plane of motion

tibiotalar

talocalcaneal

calcaneocuboid

talonavicular

naviculocuboid

Sagittal Frontal Transverse

17.5 2.9 7.5

3.7 8.9 2.9

5.9 5.9 9.9

2.1 17.7 7.9

3.3 3.1 4.3

The predominant dorsiflexion/plantarflexion in the talocrural joint and inversion / eversion at the talocalcaneal joint are generally taken into account in athletic footwear design. The amplitude of motion in the joints involving the navicular was greater than previously reported. Although inversion / eversion at the talonavicular joint was expected, the mean range of motion here (17.7 °) indicated a requirement to permit this motion either within shoes or through the shoe itself. Similarly motion in the naviculocuboid joint, although not of the same magnitude, was considerable and should be considered. Failure to appreciate such intrinsic motion may present an etiological mechanism for some foot and lower extremity injuries described in running. 4423 We, 09:15-09:30 (P28) Soccer shoe evaluation T. Sterzing, E. Hennig. Biomechanics Laboratory, University of Duisburg

Essen, Essen, Germany Introduction: Soccer requires multiple types of movement throughout the whole speed range. Companies compete to support athletes with superior footwear function. But how can shoe performance be effectively evaluated? Testing procedures use direct and indirect parameters. Direct parameters clearly quantify the performance benefit, e.g. running times or players' perception. Indirect parameters require interpretation concerning their influence on performance, e. g. foot pressures. Traction and Stability: A survey (1998) revealed traction and stability to be important features of soccer shoes. Traction performance can be directly assessed by the use of Functional Traction Parcours (FTP). This concept is shown in a study comparing different turfs and different footwear by running times of athletes [1]. FTP studies (n = 20) indicate that even slightly different stud configurations of soccer shoes influence running speed. They were found to be well suited to discriminate between soccer shoes on good and on difficult surface conditions (p<0.01). A series of FTP studies shows traction to be predominantly responsible for running speed in soccer. Stability in soccer shoes is yet not clearly defined by certain parameters. In a stability study (n=20) perception of stability in the field was linked to biomechanical measurements in the laboratory to understand the mechanisms of stability in soccer [2]. Superior stability perception was found to be coinciding with an anatomically well fitting forefoot shoe upper as indicated by lateral forefoot pressures (r2 =0.82, p <0.01). Conclusion: The combination of direct and indirect performance parameters is necessary to further enhance the quality of soccer shoes. Research was supported by Nike Inc., USA. References [1] Krahen buhl G. Speed of movement with varying footwear conditions on synthetic turf and natural grass. The Research Quarterly 1974; 45(1): 28-33. [2] Sterzing T., Hennig E. Stability in soccer shoes - the relationship between perception of stability and biomechanical parameters. Science and Football 2005. [3] Reilly V.T., Cabri J., Arat~jo D. London/New York: Routledge Taylor and Francis Group, pp. 21-27.

6375 We, 09:30-09:45 (P28) The influence of induced fatigue on ground reaction forces and rearfoot motion in running T. Milani, G. Schlee, K. Metzler. Technische Universit~t Chemnitz, Institut f~r

Sportwissenschaft, Chemnitz, Germany Several authors have studied the characteristics and modifications of induced fatigue on kinetic and kinematic variables. However, the results presented in some researches are contrary to each other (Christina, White and Gilschrist, 2001; Gerlacht et al., 2005; BrLigemman et al., 1995). The objective of this study was to analyze the effect of induced fatigue on variables derived from ground reaction forces (GRF) and rearfoot motion in running at comfortable speed. 19 subjects participated in the study (9 men, 10 women). Data collection procedures were as follows: a) the subjects ran over a 15m long walkway, with a Kistler force plate placed in the middle, at a speed of 3.5m/s (±3%); b) The subjects ran for 45 min on a treadmill with an individual speed under the anaerobic threshold (based on physiological test); c) the subjects repeated the same running procedures like (a). All subjects ran with the same shoe (neutral category & EVA midsole) that was instrumented with Hall sensors at the lateral (1) and medial rearfoot (3) areas. The Hall sensors are able to measure the vertical compression of the midsole material of the shoe. GRF data and rearfoot motion were measured by a force plate and an electrogoniometer, respectively. Only data from the right foot were collected, with a total of five steps selected for further statistical analyses. The variables First Peak Force (FPF), Force Rising Rate (FFR) and the Maximal Vertical Compression (MVD) of midsole material as well as maximal pronation (MP) and maximal pronation velocity (MPV) were calculated and analyzed. Descriptive as well as inferential statistics (ANOVA one-way) were used to compare the date before and after the induced fatigue. Significance level was set at p ~<0.05. The results of the ANOVA showed no significant differences for the analyzed variables with exception of the rearfoot motion parameters before and after the induced fatigue. MP trends to increase. MPV revealed a statistically significant increase after induced fatigue. The results show that the variables that are directly dependent from muscular control are more influenced by fatigue than footwear dependent variables. References Christina K.A., White S.C., Gilschrist, L.A. (June 2001). Effect of localized muscle fatigue on vertical ground reaction forces and ankle joint motion during running. Human Movement Sciences 20(3): 257-276. Gerlach K.E., White S.C., Burton H.W., Dorn J.M., Leddy J.J., Horvath P.J. (2005). Kinetic changes with fatigue and relationship to injury in female runners. Med Sci Sports Exerc. 37(4): 657-63. BriJgemman P., Arndt A., Kerstin U.G., Knicker A.J. (1995). Influence of fatigue on impact force and rearfoot motion during running: in H~kkinnen K., ed. XVth Congress of ISB. Jyv~skyl~ 132-133.

7196 We, 11:00-11:30 (P31) Development of e-phantoms of human foot based on 3D finite element models for foot biomechanics and support designs M. Zhang 1, J.T.-M. Cheung 1, J. Yu 1, A.K.-L. Leung 1, ~ Fan 1,2. 1Department

of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, 2Department of Bioengineering, Beihang University, China Human foot has complex structures. Information on the internal as well as footsupport interfacial load transfer during various activities is useful in enhancing our biomechanical knowledge for foot support design and surgical planning. Direct measurement of those parameters is difficult, while a comprehensive computational model can be useful. We develop computational models as foot e-phantoms which can be used to understand foot biomechanics and design proper foot supports and footwear [1-4]. Three-dimensional geometrically accurate finite element (FE) models of the human foot and ankle were developed from 3D reconstruction of MR images of subjects. The FE model consists of 28 separate bones, 72 ligaments and the plantar fascia, embedded in a volume of encapsulated soft tissue. The main bone interactions were simulated as contact deformable bodied. The analyses took into consideration the nonlinearities from material properties, large deformations and interfacial slip/friction conditions. A series of experiments on human subjects and cadavers were conducted to validate the models measurements on in terms of plantar pressure distribution, foot arch and joint motion, plantar fascia strain under different simulated weight-bearing and orthotic conditions of the foot. The validated models as e-phantoms can be used for parametrical studies to investigate the biomechanical effects of tissue stiffness, muscular reaction, surgical and orthotic performances on the ankle-foot complex. The project was supported by Hong Kong RGC (PolyU 5249/04E, PolyU5317/05E) and NSFC (10529202). References [1] Cheung JT., Zhang M., Leung AK., Fan YB. J Biomech. 2005; 38: 1045-54. [2] Cheung JT., Zhang M. Arch Phys Med Rehab. 2005; 86(2): 353-8. [3] Cheung JT., Zhang M., An KN. Clin Biomech. 2006; 21(2): 194-203.