Lecture notes Advanced Biomechanical Analysis

Biomechanics -Electromyography - 06/03/23
 Inverse Dynamics – allows us to estimate the contribution made by muscle groups not
individual muscles
o Only gives approximation
o Doesn’t give information on individual muscles
o Contains assumptions and considerable uncertainty
 Electromyography – process of recording and analysing the electrical signals generated by
muscles
o Myoelectric signal represents the summation of Motor Unit Action Potentials
(MUAPs)
 Types of EMG –
o Invasive Methods
 Needle electrodes and Fine-Wire electrodes
 Get to exactly where you want in the muscle (individual motor units)
 Record directly
 Restrict movements
 Difficult to use
 Not suitable for most biomechanics
o Surface EMG
 Easy to use
 Suitable for dynamic activities
 Superficial muscles
 Susceptible to cross-talk and other contamination
 Requires careful analysis
 Myoelectric Signals –




 Differential Amplification –
o The EMG output is the difference in voltage between the two electrodes
o Shared content (which is discarded) is assumed to be from sources other than the
target muscle
 Delsys Trigno –
o Fully wireless
o Each sensor combines:
 One channel of EMG
 Three accelerometers, set manually orthogonal orientation’s

 Accelerometers –