Helm, F.C.T. van der [Promotor]Veeger, H.E.J. [Copromotor

Praagman, M.

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Muscle load sharing
An energy-based approach
Musculoskeletal models are a valuable tool in the study on
human movement. When the kinematics and external
forces that act on the human body are known, such models
can be used to calculate the resultant joint moments for a
given posture or motion by simple Newtonian mechanics.
It is, however, difficult to determine the contribution of
the individual muscles to these moments. In general, there
are more muscles crossing a joint than is theoretically
necessary in order to perform all possible movements. This
is called the indeterminacy problem or the load sharing
problem. Inverse dynamic models often make use of cost
functions to solve this load sharing problem. The use of a
cost function is based on the assumption that the central
nervous system controls the musculoskeletal system in an
optimal manner, optimising a certain cost. It is however
difficult to find the right criterion, since it is unknown
which quantity is optimised in real life. Therefore, only
assumptions can be made. It has often been assumed that
movements are performed by minimising energy
consumption. Nevertheless, most cost functions are
mechanical cost functions and up till now, no cost
functions have been defined, which are based on the
calculation of muscle energy consumption. The aims of this
thesis were to define a cost function that represents
muscle energy consumption and to validate this cost
function with a metabolic parameter.
I K BF
I K BF
voor het bijwonen van
de openbare verdediging
van mijn proefschrift
op 23 April 2008
om 15.45 uur
in de Aula van
de Vrije Universiteit
De Boelelaan 1105
in Amsterdam
Receptie na afloop
Marit Praagman
acaciastraat 3
2023 PG Haarlem
Muscle load sharing
An energy-based approach
Uitnodiging
Paranimfen:
Kirsten Bijker
06-18324570
k.bijker@fbw.vu.nl
Marielle Stokdijk
06-52611109
stokdijk@plexus.nl


Muscle load sharing : An energy-based approach

VU Research Portal

VU Research PortalMuscle load sharingPraagman, M.2008document versionPublisher's PDF, also known as Version of recordLink to publication in VU Research Portalcitation for published version (APA)Praagman, M. (2008). Muscle load sharing: An energy-based approach. PrintPartners Ipskamp.General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            • Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            • You may not further distribute the material or use it for any profit-making activity or commercial gain            • You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.E-mail address:vuresearchportal.ub@vu.nlDownload date: 23. May. 2021Marit PraagmanMuscle load sharingMarit PraagmanAn energy-based approachMuscle load sharingAn energy-based approachMusculoskeletal models are a valuable tool in the study onhuman movement. When the kinematics and externalforces that act on the human body are known, such modelscan be used to calculate the resultant joint moments for agiven posture or motion by simple Newtonian mechanics.It is, however, difficult to determine the contribution ofthe individual muscles to these moments. In general, thereare more muscles crossing a joint than is theoreticallynecessary in order to perform all possible movements. Thisis called the indeterminacy problem or the load sharingproblem. Inverse dynamic models often make use of costfunctions to solve this load sharing problem. The use of acost function is based on the assumption that the centralnervous system controls the musculoskeletal system in anoptimal manner, optimising a certain cost. It is howeverdifficult to find the right criterion, since it is unknownwhich quantity is optimised in real life. Therefore, onlyassumptions can be made. It has often been assumed thatmovements are performed by minimising energyconsumption. Nevertheless, most cost functions aremechanical cost functions and up till now, no costfunctions have been defined, which are based on thecalculation of muscle energy consumption. The aims of thisthesis were to define a cost function that representsmuscle energy consumption and to validate this costfunction with a metabolic parameter.I K BFI K BFvoor het bijwonen vande openbare verdedigingvan mijn proefschriftop 23 April 2008om 15.45 uurin de Aula vande Vrije UniversiteitDe Boelelaan 1105in AmsterdamReceptie na afloopMarit Praagmanacaciastraat 32023 PG HaarlemMuscle load sharingAn energy-based approachUitnodigingParanimfen:Kirsten Bijker06-18324570k.bijker@fbw.vu.nlMarielle Stokdijk06-52611109stokdijk@plexus.nl

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