Correlation between surface electromyography and kinematics of the hindlimb of horses at trot on a treadmill.

The research studied the relationship between surface electromyography and movements of the hindlimb in horses while trotting on a treadmill. They found a correlation that provides useful insights into the functions and timings of the hindlimb muscles.

Method of the Research

• The researchers used surface electromyography, which is a technique to record the electrical activity of muscle tissue, on seven different hindlimb muscles in five horses.
• The horses were made to trot on a treadmill while simultaneously, their limb movements were analyzed by a three-dimensional system.
• A unidirectional accelerometer was attached to the horse’s hoof to measure acceleration related data.

Results of the Research

• The researchers found specific patterns of electromyographic activity for different muscles. The activity of the gluteus medius, vastus lateralis and two parts of the biceps femoris commenced in the latter part of the swing phase and concluded in the latter part of the stance phase or the initial period of the next swing phase.
• The semitendinosus muscle displayed two bursts of activity, while the tensor fasciae latae was active when the previous muscles were inactive.
• The activity of the extensor digitorum longus was low but lasted for most of the step cycle.

Significance of the Findings

• There were correlations between muscle activity, recorded through electromyography, kinematics (how the horse moved) and anatomy (the physical structure of the horse).
• Such correlations help understand the complex roles played by muscles that span two joints, referred to as ‘biarticular muscles’. For instance, the tensor fasciae latae, a muscle that acts on two joints, flexes the hip joint during swing and extends the knee joint during stance, whereas the semitendinosus extends the hip during stance and flexes the knee during swing.
• Both the cranial (forward) and caudal (backward) parts of the biceps femoris were found to have bifunctional, meaning it served two functions.

Conclusion

• The study asserts that surface electromyography, when used in conjunction with kinematic analysis, can provide valuable insights about the function and timing of the activity of hindlimb muscles in horses. Such information can be beneficial for veterinary science, particularly for diagnosing and treating locomotory problems in horses.