Wobbling Mass Influence on Impact Ground Reaction Forces: A Simulation Model Sensitivity Analysis

Pain, Matthew T.G.; Challis, John H.

doi:10.1123/jab.20.3.309

Cited by 24 publications

(13 citation statements)

References 13 publications

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“…While personalised model parameters such as segmental inertias may be estimated from anthropometric measurements (Jensen, 1978;Hatze, 1980) and strength parameters may be determined from isovelocity torque measurements , the determination of segmental visco-elastic parameters is less straight-forward (Pain and Challis, 2004). These parameters may be estimated indirectly from video recordings of a performance using an angle-driven human body model by minimising the difference between simulation and performance.…”

Section: Introductionmentioning

confidence: 99%

Parameter Determination for a Computer Simulation Model of a Diver and a Springboard

Yeadon

Kong

King

2006

Journal of Applied Biomechanics

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Journal of Applied Biomechanics, 22 (3), pp. [167][168][169][170][171][172][173][174][175][176] Additional Information:• AbstractThis study used kinematic data on springboard diving performances to estimate visco-elastic parameters of a planar model of a springboard and diver with wobbling masses in the trunk, thigh and calf segments and spring-dampers acting at the heel, ball and toe of the foot segment. A subject-specific angle-driven eightsegment model was used with an optimisation algorithm to determine visco-elastic parameter values by matching simulations to four diving performances. Using the parameters determined from the matching of a single dive in a simulation of another dive resulted in up to 31% difference between simulation and performance, indicating the danger of using too small a set of kinematic data. However using four dives in a combined matching process to obtain a common set of parameters resulted in a mean difference of 8.6%. Since these four dives included very different rotational requirements, it is anticipated that the combined parameter set can be used with other dives from these two groups. IntroductionA springboard diver aims to generate sufficient linear and angular momentum to somersault and twist, and to travel safely away from the board. Since the linear and angular momenta that a diver possesses during flight are determined by the end of the takeoff phase, simple models of springboard diving takeoffs have been developed to search for optimal timing of armswing (Sprigings and Watson, 1985) and knee extension (Cheng and Hubbard, 2004) to produce maximum height jumps. In such models, a linear mass-spring system with no damping (Sprigings et al., 1989) has been used to represent the vertical behaviour of the springboard. In order to understand the mechanics of the takeoff in terms of generating both linear and angular momentum, it will be necessary to model also the horizontal and rotational movement of the springboard since this will influence the diver's horizontal velocity, orientation and angular momentum.The takeoff phase of running dives begins with the touchdown on the springboard from a hurdle step in which the diver produces the initial horizontal and vertical mass centre velocities. Wobbling mass models have been used to represent soft tissue movements during impact and have been shown to reproduce better ground reaction forces than rigid body models (Gruber et al., 1998;Pain and Challis, 2001). The interface of the foot and the contact surface, such as the ground (Gilchrist and Winter, 1996) or tumbling track , has been successfully modelled using spring-damper systems. In order to model the landing on the springboard it is necessary to include visco-elastic elements allowing deformation at the foot-springboard interface since otherwise there will be an instantaneous impact between foot and board in a simulation. On the other hand it is not clear a priori whether it is necessary to include visco-elastic elements to represent soft tissue movement within body segments sin...

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Section: Introductionmentioning

confidence: 99%

Parameter Determination for a Computer Simulation Model of a Diver and a Springboard

Yeadon

Kong

King

2006

Journal of Applied Biomechanics

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“…In order to reproduce realistic ground reaction forces in pinlinked simulation models of jumping, a requirement for a high level of compliance (70 mm) at the foot-ground interface has been reported and attributed to a lack of wobbling masses (Seyfarth, 2000). Wobbling masses have been incorporated within forward dynamics models in an attempt to account for the shock attenuation properties of soft tissue during impacts (Gruber et al, 1998;Pain and Challis, 2004).…”

Section: Introductionmentioning

confidence: 99%

Models incorporating pin joints are suitable for simulating performance but unsuitable for simulating internal loading

Allen

King

Yeadon

2012

Journal of Biomechanics

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Additional Information:• This article was published in the Journal of Biomechan- AbstractSimulation models of human movement comprising pin-linked segments have a potential weakness for reproducing accurate ground reaction forces during high impact activities. While the human body contains many compliant structures such a model only has compliance in wobbling masses and in the foot-ground interface. In order to determine whether accurate GRFs can be produced by allowing additional compliance in the footground interface, a subject-specific angle-driven computer simulation model of triple jumping with 13 pin-linked segments was developed, with wobbling masses included within the shank, thigh, and trunk segments. The foot-ground interface was represented by spring-dampers at three points on each foot: the toe, ball, and heel. The parameters of the spring-dampers were varied by a genetic algorithm in order to minimise the differences between simulated GRFs, and those measured from the three phases of a triple jump in three conditions: (a) foot spring compression limited to 20 mm; (b) this compression limited to 40 mm; (c) no restrictions. Differences of 47.9%, 15.7%, and 12.4% between simulation and recorded forces were obtained for the 20 mm, 40 mm, and unrestricted conditions respectively. In the unrestricted condition maximum compressions of between 43 mm and 56 mm were obtained in the three phases and the mass centre position was within 4 mm of the actual position at these times. It is concluded that the unrestricted model is appropriate for simulating performance whereas the accurate calculation of internal forces would require a model that incorporates compliance elsewhere in the link system.

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“…Whilst it is difficult to model soft tissue response, particularly since it depends on its stiffness (i.e. activation and tension of the muscles), it has been found to reduce impact force, dissipate impact energy and reduce joint loads [20][21][22]. In particular, the energy dissipative properties of the most distal segment have been found to have the largest effect, when normalised to mass, on impact intensity [21].…”

Section: Introductionmentioning

confidence: 99%

“…activation and tension of the muscles), it has been found to reduce impact force, dissipate impact energy and reduce joint loads [20][21][22]. In particular, the energy dissipative properties of the most distal segment have been found to have the largest effect, when normalised to mass, on impact intensity [21]. As such, separating the STIMAK robot into multiple-segments could lessen the effect of the poor force attenuation properties of the current materials and reduce the limitations to the more distal segments (i.e.…”

Section: Introductionmentioning

confidence: 99%

Utilising human performance criteria and computer simulation to design a martial arts kicking robot with increased biofidelity

Tsui

Pain

2012

Proceedings of the Institution of Mechanical Engineers, Part P:

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The rules and regulations of Taekwondo stipulate how the sport must be played and the necessary personal protective equipment. As such, personal protective equipment performance under controlled rigid drop-tests is also outlined. Unfortunately, these impacts do not replicate human loading effectively, making conclusions about their performance unknown. However, it may be possible to use human kinematic data to improve the biofidelity of current impactors, including a current single-segment martial arts kicking robot. Five martial artists performed a series of roundhouse kicks while reflective markers on the kicking leg and pelvis were used to track hip, knee, ankle and foot positions. Using specific single-segment martial arts kicking robot robot parameters, computer simulation was used to model a single-segment martial arts kicking robot performance (1-SM) and to form a multi-segment, multi-joint model to match human kinematic data (3-SM). The 3-SM was found to produce similar kinematics to human performance while reducing the overall effective mass at impact, motor torque and stress concentration magnitudes in the leg when compared to the 1-SM. This study suggested that human performances could be used to improve current mechanical testing techniques without introducing much complexity to improve the external validity of protective equipment evaluation testing.

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Wobbling Mass Influence on Impact Ground Reaction Forces: A Simulation Model Sensitivity Analysis

Cited by 24 publications

References 13 publications

Parameter Determination for a Computer Simulation Model of a Diver and a Springboard

Parameter Determination for a Computer Simulation Model of a Diver and a Springboard

Models incorporating pin joints are suitable for simulating performance but unsuitable for simulating internal loading

Utilising human performance criteria and computer simulation to design a martial arts kicking robot with increased biofidelity

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