**Author details**

Raison Maxime, Laitenberger Maria and Sarcher Aurélie

*Research Chair in Pediatric Rehabilitation Engineering (CPRE), École Polytechnique de Montréal and CRME - Sainte-Justine UHC, Montreal, Canada*

### Detrembleur Christine

*Institute of NeuroScience (IoNS), Université catholique de Louvain (UCL), Brussels, Belgium*

### Samin Jean-Claude and Fisette Paul

*Centre for Research in Mechatronics (CEREM), Institute of Mechanics, Materials, and Civil Engineering (iMMC), Université catholique de Louvain (UCL), Louvain-la-Neuve, Belgium*

### **5. References**


[6] Wetzel JL, Fry DK, Pfalzer LA (2011) Six-minute walk test for persons with mild or moderate disability from multiple sclerosis: performance and explanatory factors. Physiother Can 63(2): 166-80.

16 Biomechanics

Finally, in the context of the hardness to perform efforts, the perspectives of this research is to quantify with a satisfying accuracy the main joint and muscle efforts of subjects in different

• physical therapy, in order to analyze joint efforts of subjects in different motion contexts, particularly for the evaluation, the follow-up and the treatment of patients in rehabilitation

• comfort analysis is vehicle and car occupant dynamics, in order to analyze the hardness of going into and out of vehicles, and simulate the car occupant dynamics before crash.

The research is supported by MÉDITIS training program, supported by NSERC/FONCER,

*Research Chair in Pediatric Rehabilitation Engineering (CPRE), École Polytechnique de Montréal and*

*Centre for Research in Mechatronics (CEREM), Institute of Mechanics, Materials, and Civil*

[1] Bohannon RW (2011) Test-retest reliability of the five-repetition sit-to-stand test: a systematic review of the literature involving adults. J Strength Cond Res 25(11): 3205-7. [2] Dos Santos AN, Pavão SL, Rocha NA (2011) Sit-to-stand movement in children with

[3] Wang TH, Liao HF, Peng YC (2011) Reliability and validity of the five-repetition sit-to-stand test for children with cerebral palsy. Clin Rehabil. Epub ahead of print. [4] Duncan RP, Leddy AL, Earhart GM (2011) Five times sit-to-stand test performance in

[5] Jovic J, Fraisse P, Coste CA, Bonnet V, Fattal C (2011) Improving valid and deficient body segment coordination to improve FES-assisted sit-to-stand in paraplegic subjects. IEEE

*Institute of NeuroScience (IoNS), Université catholique de Louvain (UCL), Brussels, Belgium*

*Engineering (iMMC), Université catholique de Louvain (UCL), Louvain-la-Neuve, Belgium*

cerebral palsy: a critical review. Res Dev Disabil 32(6): 2243-52.

Parkinson's disease. Arch Phys Med Rehabil 92(9): 1431-6.

Int Conf Rehabil Robot. Jun 29 - Jul 1.

the body configuration, external force and torque measurements.

dynamical contexts, and to apply the model to:

Raison Maxime, Laitenberger Maria and Sarcher Aurélie

*CRME - Sainte-Justine UHC, Montreal, Canada*

Samin Jean-Claude and Fisette Paul

**4.2. Perspectives**

and orthopedics;

**Acknowledgements**

Canada.

**Author details**

Detrembleur Christine

**5. References**

motions are presently inappropriate to the human body dynamics, because the resulting body parameters present large errors due to experimental errors in the input data, such as


© 2012 Mizrahi and Daily, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

**Modeling the Foot-Strike Event in Running** 

The human motor system benefits from remarkable muscular redundancies: A motor task is normally performed with the simultaneous involvement of more muscles than strictly necessary. Furthermore, this same task may be performed in multiple ways, with different muscle combinations. From the mechanical viewpoint the musculoskeletal system is indeterminate, whereby the number of unknown muscle forces exceeds the number of available equations. We address in this Chapter the biomechanics of the lower limbs in longdistance running under conditions of developing fatigue. In long-distance running the running speed may result in more than 300 foot-strikes per leg per kilometer. Each such foot-strike evokes an impact loading that results in a vertical shock impulse transmitted upwards through the body and carries with it the potential for injuries in the bone and joint

Fatigue, or stress, fractures occur in bones in response to repetitive stresses over multiple cycles, when the body's ability to adapt is exceeded [1,2]. An important factor which affects the incidence of bone stress injury, is exposure to abrupt changes in the bone loading [1], and consequent alteration in the strain distribution [3] with insufficient recovery periods [4].

Two of the major factors responsible for impulse attenuation at foot- or heel-strike are the shock absorption capacity of the active muscle in the lower limbs, and the cushioning effect of the foot heel-pad tissue. In previous reports we have shown that in long distance running the impact shock load on the lower limbs increases with progressing fatigue [5-8]. One additional question is whether, as a result of fatigue, an imbalance between the activities of the plantar and dorsi flexor muscles of the ankle develops. Such an imbalance would compromise the protective action provided by the muscles to the

and reproduction in any medium, provided the original work is properly cited.

Other factors include footwear, terrain and intensity of activity or training [1].

**Fatigue via Mechanical Impedances** 

Additional information is available at the end of the chapter

J. Mizrahi and D. Daily

http://dx.doi.org/10.5772/48784

**1. Introduction** 

tissues.

shank [9-11].
