6 of 12 Top Hip Papers – Gluteus Minimus EMG in Gait

PAPER 6: Gluteus minimus: An intramuscular EMG investigation of anterior and posterior segments during gait

Prior to this work, the only electromyographic (EMG) study published for gluteus minimus was in 1976, reporting data from a single electrode during hip motions in lying. Almost 4 decades later, Adam Semciw and colleagues delivered some much-awaited functional EMG data for this incredibly important muscle. With strong attachments to the joint capsule, the gluteus minimus is thought to contribute significantly to control of capsular tension, femoral head translation and joint stability, playing an integral role in joint protection. This was the first study to collect separate information on anterior and posterior fibres of gluteus minimus, able to then determine conclusively that gluteus minimus is composed of functionally unique segments and that they behave differently during function.

Key learnings about gluteus minimus EMG in gait:

While these segments co-contract during gait, their peaks of activation are different:

• the posterior fibres peak during early stance to assist in controlling the posteriorly directed ground reaction force that challenges the posterior capsule in the loading phase of gait,
• the anterior fibres peak in activation in late stance, to control the anteriorly directed forces during hip extension.

This paper also reported activation of the segments during hip motion, showing that:

• the anterior segment is more active than the posterior segment during hip internal rotation,
• the posterior segment is much more active than the anterior segment during the clam action (hip abduction – external rotation),
• both segments are strongly active in resisted hip extension – reflecting a joint stability role rather than a torque production role in this action.

These authors had also published an EMG technique paper in the previous year. These papers opened the doors for others to research the function of this deep hip muscle… and they did. We now have further information on the function of this muscle in those with hip pain and pathology with direct implications for intervention. While there is still much more to explore, science now has the capacity to provide the answers.