The main action of the gluteus maximus is to extend the hip, but many times we forget about the secondary and tertiary actions of the glute max and the assistance that the smaller, deeper medius and minimus muscles assist in:
To activate the glutes and elicit the desired training response, all four gluteal actions must be targeted and trained to some extent. Neglecting any of these actions leaves strength and growth potential on the table, while increasing likelihood of compensatory patterns, joint stress, and risk of injury in the process.
Based on hip anthropometrics, body typing, movement skill and past history, each set of glutes is unique, which makes the need to optimal activation highly individualized. What we do know is that doing as many gluteal actions as possible is ideal, no matter the individual variances of biomechanics or neural drive.