Lower extremity electromyographic analysis of running gait

Area of Science:

• Biomechanics
• Human Movement Science
• Sports Medicine

Background:

• Understanding muscle activation patterns during locomotion is essential for diagnosing gait abnormalities and optimizing athletic performance.
• Surface electromyography (sEMG) and indwelling wire electrodes are common methods for measuring muscle activity, but their comparability in dynamic activities like running requires validation.

Purpose of the Study:

• To compare the onset of muscle firing in major lower limb muscle groups (quadriceps, hamstrings, gastroc soleus) during over-ground and treadmill running.
• To assess the equivalence of data obtained from surface electrodes versus indwelling wire electrodes for muscle activity onset detection.

Main Methods:

• Seven healthy adult males performed running trials on a treadmill and over ground.
• Simultaneous electromyography (EMG) data were collected using both surface and wire electrodes from quadriceps, hamstrings, and gastroc soleus muscle groups.
• Muscle onset timing was analyzed across 959 individual gait cycles, comparing left/right limb symmetry and electrode type differences.

Main Results:

• No statistically significant differences were found in the onset of muscle activity between left and right limbs.
• The average difference in onset timing between surface and wire electrodes was minimal and not statistically significant for both treadmill (2%) and over-ground (1.5%) running.
• Running parameters like velocity, cadence, and swing/stance ratios differed between treadmill and over-ground conditions.

Conclusions:

• Surface and wire EMG electrodes yield comparable results for determining the onset of muscle activity in synergistic lower limb muscle groups during running.
• The findings support the use of surface EMG as a valid and less invasive method for assessing muscle activation timing in running biomechanics.
• Data from surface electrodes should be interpreted cautiously when analyzing individual muscle function within a synergistic group.