effective mechanical advantage

Related terms

moment arm ratio ful95a
musculo-apodeme moment arm ful95a
leg moment arm ful95a
abbreviation: EMA bie89a
forelimb effective mechanical advantage bie89a
hindlimb effective mechanical advantage bie89a

Definitions

The effective mechanical advantage (EMA) is a kind of moment arm ratio. For example, Full and Ahn (ful95a) define the EMA as the ratio of the musculo-apodeme moment arm to the leg moment arm:

$\begin{align*} \text{effective mechanical advantage} &= \frac{\text{moment arm length of the muscle}}{\text{ground reaction force moment arm}}\\ &=\frac{\text{musculo-apodeme moment arm}}{\text{leg moment arm}} \end{align*}$

Biewener (bie89a) defines the EMA "as the ratio of the extensor muscle moment arm (r) to the moment arm of the ground reaction force (R) acting about the joint.".

Bibliography

[ful95a] Full & Ahn, Static forces and moments generated in the insect leg: comparison of a three-dimensional musculo-skeletal computer model with experimental measurements, J. Exp. Biol., 198, 1285-1298 (1995). link.
[bie89a] Biewener, Scaling body support in mammals: limb posture and muscle mechanics, Science, 245, (1989). link. doi.