Repeatability of wire and surface electrodes in gait

Area of Science:

• Biomechanics
• Neuroscience
• Kinesiology

Background:

• Muscle force measurement often relies on indirect methods like dynamic electromyography (EMG).
• The choice between surface and intramuscular electrodes for EMG in gait analysis is debated due to factors like invasiveness and signal quality.
• Intramuscular electrodes offer potential for deep or small muscles but require skin penetration and expertise.

Purpose of the Study:

• To compare the test-retest reliability of surface electrodes versus intramuscular (wire) electrodes for dynamic electromyography during gait analysis.
• To address the controversy surrounding electrode type selection in EMG studies of human motion.

Main Methods:

• Dynamic electromyographic data were collected from the soleus muscle in 18 healthy adults during walking.
• The variance ratio statistical criterion was employed to assess the reproducibility of muscle activity patterns.
• Repeat-day testing was conducted to evaluate test-retest reliability for both electrode types.

Main Results:

• Both surface and intramuscular (wire) electrodes demonstrated high consistency in capturing muscle activity patterns.
• Mean variance ratio values were slightly lower for wire electrodes (187) compared to surface electrodes (199).
• The observed differences in reliability between the two electrode types were not statistically significant (P = 0.768).

Conclusions:

• Dynamic electromyography signals obtained using wire electrodes exhibit at least the same level of repeatability as those from surface electrodes.
• This finding supports the use of wire electrodes in gait analysis, particularly when deep or small muscles are of interest.