Umberger2010MuscleMetabolicsProbe is a Probe ModelComponent for computing the net metabolic energy rate of a set of Muscles in the model during a simulation. More...

Inheritance diagram for OpenSim::Umberger2010MuscleMetabolicsProbe:

Static Public Member Functions
Auto-generated functions
static Umberger2010MuscleMetabolicsProbe *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...

Static Public Member Functions inherited from OpenSim::Probe
static Probe *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...

static const std::string &	getClassName ()
	This returns "Probe" More...

Static Public Member Functions inherited from OpenSim::ModelComponent
static ModelComponent *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...

static const std::string &	getClassName ()
	This returns "ModelComponent" More...

Static Public Member Functions inherited from OpenSim::Component
static Component *	safeDownCast (OpenSim::Object *obj)
	For use in MATLAB and Python to access the concrete class. More...

static const std::string &	getClassName ()
	This returns "Component" More...

Static Public Member Functions inherited from OpenSim::Object
static void	registerType (const Object &defaultObject)
	Register an instance of a class; if the class is already registered it will be replaced. More...

static void	renameType (const std::string &oldTypeName, const std::string &newTypeName)
	Support versioning by associating the current Object type with an old name. More...

static const Object *	getDefaultInstanceOfType (const std::string &concreteClassName)
	Return a pointer to the default instance of the registered (concrete) Object whose class name is given, or NULL if the type is not registered. More...

template<class T >
static bool	isObjectTypeDerivedFrom (const std::string &concreteClassName)
	Return true if the given concrete object type represents a subclass of the template object type T, and thus could be referenced with a T*. More...

static Object *	newInstanceOfType (const std::string &concreteClassName)
	Create a new instance of the concrete Object type whose class name is given as concreteClassName. More...

static void	getRegisteredTypenames (Array< std::string > &typeNames)
	Retrieve all the typenames registered so far. More...

template<class T >
static void	getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray)
	Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete. More...

static bool	PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName, bool printFlagInfo=true)
	Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects. More...

static bool	PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName, bool printFlagInfo=true)
	Same as the other signature but the class name and property name are provided as two separate strings. More...

static Object *	makeObjectFromFile (const std::string &fileName)
	Create an OpenSim object whose type is based on the tag at the root node of the XML file passed in. More...

static const std::string &	getClassName ()
	Return the name of this class as a string; i.e., "Object". More...

static void	setSerializeAllDefaults (bool shouldSerializeDefaults)
	Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More...

static bool	getSerializeAllDefaults ()
	Report the value of the "serialize all defaults" flag. More...

static bool	isKindOf (const char *type)
	Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More...

static void	setDebugLevel (int newLevel)
	Set the amount of logging output. More...

static int	getDebugLevel ()
	Get the current setting of debug level. More...

static Object *	SafeCopy (const Object *aObject)
	Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned. More...

static void	RegisterType (const Object &defaultObject)
	OBSOLETE alternate name for registerType(). More...

static void	RenameType (const std::string &oldName, const std::string &newName)
	OBSOLETE alternate name for renameType(). More...

Auto-generated functions <br>
static const std::string &	getClassName ()
	This returns "Umberger2010MuscleMetabolicsProbe" More...

Umberger2010MuscleMetabolicsProbe *	clone () const override
	Create a new heap-allocated copy of the concrete object to which this Object refers. More...

const std::string &	getConcreteClassName () const override
	Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...

Additional Inherited Members
Public Member Functions inherited from OpenSim::Probe
Public Member Functions inherited from OpenSim::ModelComponent
	ModelComponent ()
	Default constructor. More...

	ModelComponent (const std::string &aFileName, bool aUpdateFromXMLNode=true)
	Construct ModelComponent from an XML file. More...

	ModelComponent (SimTK::Xml::Element &aNode)
	Construct ModelComponent from a specific node in an XML document. More...

virtual	~ModelComponent ()
	Destructor is virtual to allow concrete model component cleanup. More...

void	connectToModel (Model &model)
	Connect this ModelComponent to its aggregate- a Model. More...

const Model &	getModel () const
	Get a const reference to the Model this component is part of. More...

Model &	updModel ()
	Get a modifiable reference to the Model this component is part of. More...

bool	hasModel () const
	Does this ModelComponent have a Model associated with it? More...

void	preScale (const SimTK::State &s, const ScaleSet &scaleSet)
	Perform any computations that must occur before ModelComponent::scale() is invoked on all ModelComponents in the Model. More...

void	scale (const SimTK::State &s, const ScaleSet &scaleSet)
	Scale the ModelComponent. More...

void	postScale (const SimTK::State &s, const ScaleSet &scaleSet)
	Perform any computations that must occur after ModelComponent::scale() has been invoked on all ModelComponents in the Model. More...

Public Member Functions inherited from OpenSim::Component
Public Member Functions inherited from OpenSim::Object
virtual	~Object ()
	Virtual destructor for cleanup. More...

bool	isEqualTo (const Object &aObject) const
	Equality operator wrapper for use from languages not supporting operator overloading. More...

Object &	operator= (const Object &aObject)
	Copy assignment copies he base class fields, including the properties. More...

virtual bool	operator== (const Object &aObject) const
	Determine if two objects are equal. More...

virtual bool	operator< (const Object &aObject) const
	Provide an ordering for objects so they can be put in sorted containers. More...

void	setName (const std::string &name)
	Set the name of the Object. More...

const std::string &	getName () const
	Get the name of this Object. More...

void	setDescription (const std::string &description)
	Set description, a one-liner summary. More...

const std::string &	getDescription () const
	Get description, a one-liner summary. More...

const std::string &	getAuthors () const
	Get Authors of this Object. More...

void	setAuthors (const std::string &authors)
	Set Authors of this object. More...

const std::string &	getReferences () const
	Get references or publications to cite if using this object. More...

void	setReferences (const std::string &references)
	Set references or publications to cite if using this object. More...

int	getNumProperties () const
	Determine how many properties are stored with this Object. More...

const AbstractProperty &	getPropertyByIndex (int propertyIndex) const
	Get a const reference to a property by its index number, returned as an AbstractProperty. More...

AbstractProperty &	updPropertyByIndex (int propertyIndex)
	Get a writable reference to a property by its index number, returned as an AbstractProperty. More...

bool	hasProperty (const std::string &name) const
	Return true if this Object has a property of any type with the given name, which must not be empty. More...

const AbstractProperty &	getPropertyByName (const std::string &name) const
	Get a const reference to a property by its name, returned as an AbstractProperty. More...

AbstractProperty &	updPropertyByName (const std::string &name)
	Get a writable reference to a property by its name, returned as an AbstractProperty. More...

template<class T >
bool	hasProperty () const
	Return true if this Object contains an unnamed, one-object property that contains objects of the given template type T. More...

template<class T >
const Property< T > &	getProperty (const PropertyIndex &index) const
	Get property of known type Property<T> as a const reference; the property must be present and have the right type. More...

template<class T >
Property< T > &	updProperty (const PropertyIndex &index)
	Get property of known type Property<T> as a writable reference; the property must be present and have the right type. More...

bool	isObjectUpToDateWithProperties () const
	Returns `true` if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called. More...

void	readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
	We're given an XML element from which we are to populate this Object. More...

void	updateXMLNode (SimTK::Xml::Element &parent, const AbstractProperty *prop=nullptr) const
	Serialize this object into the XML node that represents it. More...

bool	getInlined () const
	Inlined means an in-memory Object that is not associated with an XMLDocument. More...

void	setInlined (bool aInlined, const std::string &aFileName="")
	Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case. More...

std::string	getDocumentFileName () const
	If there is a document associated with this object then return the file name maintained by the document. More...

int	getDocumentFileVersion () const
	If there is a document associated with this object then return its version number. More...

void	setAllPropertiesUseDefault (bool aUseDefault)

bool	print (const std::string &fileName) const
	Write this Object into an XML file of the given name; conventionally the suffix to use is ".osim". More...

std::string	dump () const
	dump the XML representation of this Object into an std::string and return it. More...

virtual bool	isA (const char *type) const
	The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name. More...

const std::string &	toString () const
	Wrapper to be used on Java side to display objects in tree; this returns just the object's name. More...

PropertySet &	getPropertySet ()
	OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...

const PropertySet &	getPropertySet () const

Detailed Description

Umberger2010MuscleMetabolicsProbe is a Probe ModelComponent for computing the net metabolic energy rate of a set of Muscles in the model during a simulation.

Umberger2010MuscleMetabolicsProbe Theory

The discussion here is based on the following papers:

Uchida, T. K., Hicks, J. L., Dembia, C. L., Delp, S. L. (2016). Stretching your energetic budget: how tendon compliance affects the metabolic cost of running. PLOS ONE 11(3), e0150378.

Umberger, B. R. (2010). Stance and swing phase costs in human walking. J R Soc Interface 7, 1329-40.

Umberger, B. R., Gerritsen, K. G. and Martin, P. E. (2003). A model of human muscle energy expenditure. Comput Methods Biomech Biomed Engin 6, 99-111.

Note that the equations below that describe the particular implementation of Umberger2010MuscleMetabolicsProbe may slightly differ from the equations described in the representative publications above. Note also that we define positive muscle velocity to indicate lengthening (eccentric contraction) and negative muscle velocity to indicate shortening (concentric contraction).

Muscle metabolic power (or rate of metabolic energy consumption) is equal to the rate at which heat is liberated plus the rate at which work is done:
Edot = Bdot + sumOfAllMuscles(Adot + Mdot + Sdot + Wdot).

Bdot is the basal heat rate (W).
Adot is the activation heat rate (W).
Mdot is the maintenance heat rate (W).
Sdot is the shortening heat rate (W).
Wdot is the mechanical work rate (W).

This probe also uses muscle parameters stored in the MetabolicMuscle object for each muscle. The full set of all MetabolicMuscles (MetabolicMuscleSet) is a property of this probe:

m = The mass of the muscle (kg).
r = Ratio of slow-twitch fibers in the muscle (between 0 and 1).

The recruitment model described by Bhargava et al. (2004) is used to set the slow-twitch fiber ratio used in the calculations below. The ratio specified by the user indicates the composition of the muscle; this value is used only at full excitation (i.e., when all fibers are recruited). As excitation decreases from 1 to 0, the proportion of recruited fibers that are slow-twitch fibers increases from r to 1. See Bhargava, L.J., Pandy, M.G., Anderson, F.C. (2004) A phenomenological model for estimating metabolic energy consumption in muscle contraction. J Biomech 37:81-88 and Uchida et al. (2016). To assume a constant ratio of slow- and fast-twitch fiber recruitment, set the 'use_Bhargava_recruitment_model' property to false.

BASAL HEAT RATE (W)

If basal_rate_on is set to true, then Bdot is calculated as follows:
Bdot = basal_coefficient * (m_body^basal_exponent)

m_body = mass of the entire model
basal_coefficient and basal_exponent are defined by their respective properties.
Note that this quantity is muscle independent. Rather it is calculated on a whole body level.

ACTIVATION & MAINTENANCE HEAT RATE (W)

If activation_maintenance_rate_on is set to true, then Adot+Mdot is calculated as follows:
Adot+Mdot = [128*(1-r) + 25] * A^0.6 * S , l_CE <= l_CE_opt
Adot+Mdot = (0.4*[128*(1-r) + 25] + 0.6*[128*(1-r) + 25]*F_CE_iso) * A^0.6 * S , l_CE > l_CE_opt

A = u , u > a
A = (u+a)/2 , u <= a
m = The mass of the muscle (kg).
l_CE = muscle fiber length at the current time.
l_CE_opt = optimal fiber length of the muscle.
F_CE_iso = normalized contractile element force-length curve.
u = muscle excitation at the current time.
a = muscle activation at the current time.
S = aerobic/anaerobic scaling factor, defined by the 'aerobic_factor' property (i.e. usually 1.0 for primarily anaerobic activities, 1.5 for primarily aerobic activities).

SHORTENING HEAT RATE (W)

If shortening_rate_on is set to true, then Sdot is calculated as follows:
Sdot = m * (-[(alphaS_slow * v_CE_norm * r) + (alphaS_fast * v_CE_norm * (1-r))] * A^2 * S) , l_CE <= l_CE_opt & v_CE >= 0 (concentric / isometric contraction)
Sdot = m * (-[(alphaS_slow * v_CE_norm * r) + (alphaS_fast * v_CE_norm * (1-r))] * A^2 * S * F_iso) , l_CE > l_CE_opt & v_CE >= 0 (concentric / isometric contraction)
Sdot = m * (alphaL * v_CE_norm * A * S) , l_CE <= l_CE_opt & v_CE < 0 (eccentric contraction)
Sdot = m * (alphaL * v_CE_norm * A * S * F_CE_iso) , l_CE > l_CE_opt & v_CE < 0 (eccentric contraction)

A = u , u > a
A = (u+a)/2 , u <= a
alphaS_fast = 153 / v_CE_max
alphaS_slow = 100 / (v_CE_max / 2.5)
alphaL = 4.0 * alphaS_slow
m = The mass of the muscle (kg).
l_CE = muscle fiber length at the current time.
l_CE_opt = optimal fiber length of the muscle.
F_CE_iso = force that would be developed by the contractile element of muscle under isometric conditions with the current activation and fiber length.
v_CE = muscle fiber velocity at the current time.
v_CE_max = maximum shortening velocity of the muscle.
v_CE_norm = normalized muscle fiber velocity (defined for this model as v_CE/l_CE_opt). Note that this is a different metric to the typical normalized_muscle_fiber_velocity of v_CE/v_CE_max.
S = aerobic/anaerobic scaling factor, defined by the 'aerobic_factor' property (i.e. usually 1.0 for primarily anaerobic activities, 1.5 for primarily aerobic activities).

MECHANICAL WORK RATE (W)

If mechanical_work_rate_on is set to true, then Wdot is calculated as follows:
Wdot = -(F_CE * v_CE)

v_CE = muscle fiber velocity at the current time.
F_CE = force developed by the contractile element of muscle at the current time.
If we draw a control volume around the fiber, the first law of thermodynamics suggests that negative mechanical work should be included in Wdot. As such, we revert back to the model described in Umberger et al. (2003) by default. To exclude negative mechanical work from Wdot and use a coefficient of 0.3 (rather than 4.0) to calculate alpha_L, set the 'include_negative_mechanical_work' property to false.

During eccentric contraction, the magnitude of the (negative) mechanical work rate can exceed that of the total (positive) heat rate, resulting in a flow of energy into the fiber. Experiments indicate that the chemical processes involved in fiber contraction cannot be reversed, and most of the energy that is absorbed during eccentric contraction (in increased cross-bridge potentials, for example) is eventually converted into heat. Thus, we increase Sdot (if necessary) to ensure Edot > 0 for each muscle. See Constable, J.K., Barclay, C.J., Gibbs, C.L. (1997) Energetics of lengthening in mouse and toad skeletal muscles. J Physiol 505:205-215 and Uchida et al. (2016). To allow muscles to have negative total power, set the 'forbid_negative_total_power' property to false.

Note that if enforce_minimum_heat_rate_per_muscle == true AND activation_maintenance_rate_on == shortening_rate_on == true, then the total heat rate (AMdot + Sdot) will be capped to a minimum value of 1.0 W/kg (Umberger(2003), page 104).

Umberger2010MuscleMetabolicsProbe_MetabolicMuscleParameter

Umberger2010MuscleMetabolicsProbe_MetabolicMuscleParameter is an Object class that holds the metabolic parameters required to calculate metabolic power for a single muscle.

Umberger2010MuscleMetabolicsProbe_MetabolicMuscleParameter Properties

REQUIRED PROPERTIES

specific_tension = The specific tension of the muscle (Pascals (N/m^2)).
density = The density of the muscle (kg/m^3).
ratio_slow_twitch_fibers = Ratio of slow twitch fibers in the muscle (must be between 0 and 1).

OPTIONAL PROPERTIES

use_provided_muscle_mass = An optional flag that allows the user to explicitly specify a muscle mass. If set to true, the 'provided_muscle_mass' property must be specified. The default setting is false, in which case, the muscle mass is calculated from the following formula: m = (Fmax/specific_tension)*density*Lm_opt, where specific_tension and density are properties defined above (note that their default values are set based on mammalian muscle, 0.25e6 N/m^2 and 1059.7 kg/m^3, respectively); Fmax and Lm_opt are the maximum isometric force and optimal fiber length, respectively, of the muscle.
provided_muscle_mass = The user specified muscle mass (kg).

Author: Tim Dorn

Member Function Documentation

◆ clone()

Umberger2010MuscleMetabolicsProbe * OpenSim::Umberger2010MuscleMetabolicsProbe::clone ( ) const

inlineoverridevirtual

Create a new heap-allocated copy of the concrete object to which this Object refers.

It is up to the caller to delete the returned object when no longer needed. Every concrete object deriving from Object implements this pure virtual method automatically, via the declaration macro it invokes (e.g., OpenSim_DECLARE_CONCRETE_OBJECT()). Note that the concrete class overrides modify the return type to be a pointer to the concrete object; that still overrides the base class method because the return type is covariant with (that is, derives from) Object.

Implements OpenSim::Probe.

◆ getClassName()

static const std::string & OpenSim::Umberger2010MuscleMetabolicsProbe::getClassName ( )

inlinestatic

This returns "Umberger2010MuscleMetabolicsProbe"

See getConcreteClassName() if you want the class name of the underlying concrete object instead.

◆ getConcreteClassName()

const std::string & OpenSim::Umberger2010MuscleMetabolicsProbe::getConcreteClassName ( ) const

inlineoverridevirtual

Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string.

This is the string that is used as the tag for this concrete object in an XML file. Every concrete class derived from Object automatically overrides this method via the declaration macro it uses. See getClassName() to get the class name of the referencing (possibly abstract) class rather than the concrete object.

See also: getClassName()

Implements OpenSim::Probe.

◆ safeDownCast()

static Umberger2010MuscleMetabolicsProbe * OpenSim::Umberger2010MuscleMetabolicsProbe::safeDownCast ( OpenSim::Object * obj )