How should we train the gluteus maximus?

How can we design a strength training program that will maximize the growth of the gluteus maximus or “glutes”? What factors do we need to take into consideration, and how do each of these factors affect the different variables within the training program?

What information do we need?

We can use the research literature to enhance our training programs if we search for information about the gross anatomy, regional anatomy, and internal moment arm lengths of a muscle, in addition to its working sarcomere lengths, and susceptibility to muscle damage. Each of these factors provides information that is useful for different reasons (read more).

• Gross anatomy describes the locations of the attachments of the muscle to the skeleton. Learning the basic anatomy of a muscle helps us figure out suitable exercises, and also helps us see how we might alter them to target different muscles within a group.
• Regional anatomy describes the way in which a muscle divides into several internal regions, and this tells us whether we are going to need multiple exercises to train the muscle.
• The internal moment arm lengths of a muscle determine its leverage on the joint, and therefore its contribution to a joint moment, relative to other agonist muscles. This allows us to see where peak force in an exercise joint range of motion needs to be, to target one muscle within a group (or one region of a muscle). We can alter the point where peak force occurs by our exercise selection and by our choice of external resistance type.
• The working sarcomere lengths describe the lengths of the sarcomeres inside a muscle over its joint angle range of motion. It allows us to see if the muscle can experience (1) active insufficiency (and so will be trained poorly by exercises involving peak forces at very short muscle lengths), and (2) stretch-mediated hypertrophy (and so will be trained more effectively by exercises involving peak forces at very long muscle lengths).
• The susceptibility of a muscle to damage is how easily a muscle is damaged by a workout. It is affected by: (1) muscle fiber type proportion, (2) its level of voluntary activation, and (3) the working sarcomere lengths of its muscle fibers. The amount of muscle damage that a muscle experiences after a workout is the main determinant of the frequency (and volume) we can use for training it, and it also influences our choice of exercises (single-joint vs. multi-joint, single-limb vs. multi-limb, and full vs. partial range of motion).

#1. Anatomy

Unlike other muscles, the human gluteus maximus is different in size and shape from the same muscle in other primates, for reasons that are hotly debated. Specifically, the gluteus maximus is far larger in humans than in other apes (indeed, it is actually the largest muscle in the human body), which seems to be due mainly to an increased size of the upper (cranial) region, and it has an extra origin on the pelvis (at the iliac crest) in addition to the origins that other primates have on the lower spinal vertebrae. Given that humans spend more time standing in an upright position than other apes, it seems logical that the different size and shape of the muscle might be related to this activity. Yet, the gluteus maximus is largely inactive during standing, which suggests that its function in humans was developed in response to other requirements. Exactly what these requirements are is still unclear.

The gluteus maximus (like the gluteus medius) is innervated by the inferior gluteal nerve, which branches out from the spinal cord at the L5 and S1 vertebrae. The muscle has a wide variety of origins, including the ilium, the posterior quarter of the iliac crest, the posterior surfaces of the sacrum and coccyx, the thoracolumbar fascia and the fascias of the lumbar spine and gluteus medius, the erector spinae aponeurosis, and the dorsal sacroiliac and sacrotuberous ligaments. It has two main insertions. Firstly, it inserts on the oblique ridge on the lateral surface of the greater trochanter of the femur. Secondly, it inserts on the iliotibial band (ITB) of the fascia lata. In fact, some researchers have suggested that the ITB could be characterized as a tendon of insertion for the gluteus maximus. Since the ITB attaches to the lateral tibial condyle, this insertion point connects the gluteus maximus with the lower limb, below the knee, although the implications of this link are unclear. This complex array of origins and insertions allows the gluteus maximus to carry out a wide variety of joint actions, including hip or trunk extension (and posterior pelvic tilt), hip external rotation, and hip abduction.

Practical implications

In practice, the gluteus maximus is the largest muscle in the human body, and therefore developing it will likely contribute substantially to increases in whole body muscle mass. It has a wide variety of origins and insertions, and likely fulfils a number of different functions, including hip and trunk extension, hip external rotation, hip abduction, and posterior pelvic tilt.

#2. Regional anatomy

Upper and lower regions

Few studies have performed anatomical investigations into the different regions of the gluteus maximus, although many anatomical texts have noted the presence of upper (also called superior or cranial) and lower (also called inferior or caudal) regions, which might result from the fusion of two distinct fetal muscles, and which seem to have quite different origins and insertions. The upper region originates on the posterior iliac crest and inserts into the iliotibial tract of the fascia lata. These anatomical features allow the upper region of the muscle to contribute to hip external rotation and abduction, while also performing hip extension. In contrast, the lower region originates from the inferior sacrum and upper lateral coccyx, and inserts into the lateral intermuscular septum and the femur. The insertion on the femur can be up to a third of the way down the thigh, allowing a substantial contribution to hip extension, but a much smaller contribution to hip external rotation or hip abduction.

Assessments of the regional muscle activation of the gluteus maximus using electromyography (EMG) provide further evidence for two distinct regions of the muscle, and demonstrate that these regions contribute differently to different hip joint actions. In agreement with an analysis of gluteal anatomy, the lower region of the glutes seems to be active mainly in performing hip extension, while the upper glutes contribute variously to hip extension, hip abduction, and hip external rotation.

Research using mechanomyography (MMG), a method that detects the low frequency vibrations that are produced when a muscle contracts, has also shown that the gluteus maximus muscle can be subdivided into different regions (upper, middle, and lower). Mean contraction time is longest in the upper region, followed by the middle region, and then the lower region. This may indicate differences in muscle fiber type between the upper and lower regions of the gluteus maximus. Since the upper region appears to display slower contractile characteristics, it may have a greater proportion of type I muscle fibers. Consequently, this region may have developed to fulfil postural functions, such as trunk extension or control of hip adduction during gait. Since the upper fibers have a longer abductor moment arm, this seems logical. In contrast, the (middle and) lower regions display faster contractile characteristics, so may comprise a greater proportion of type II muscle fibers. This may support their role in producing forceful hip extension movements of the lower body, such as jumping and sprinting.

Superficial and deep regions

In contrast to the majority of research that has identified different upper and lower regions of the gluteus maximus, some investigators have found the presence of superficial and deep regions. Specifically, there may be different superficial sacral, deep sacral, and deep ilium regions. The superficial sacral fibers originate on the sacrum and insert on the iliotibial band (ITB) or gluteal tuberosity of the femur. The deep ilium fibers originate on the ilium and insert on the gluteal tuberosity. The deep sacral fibers originate on the lateral side of the sacrum, cross the sacroiliac joint and insert just lateral to the posterior superior iliac spine. Given the slightly different attachment points, it seems likely that these different regions may fulfil different functional purposes.

Practical implications

In practice, the gluteus maximus can be subdivided into upper and lower regions, which contribute differently to different hip joint actions. The lower region of the glutes is active mainly in hip extension, while the upper glutes contribute to hip extension, hip abduction, and hip external rotation. Additional subdivisions, such as into superficial and deep regions, may also be present. This suggests that the muscle may benefit from being trained with multiple, different exercises.

#3. Internal moment arm lengths

Hip extension

The glutes are primarily hip extensors, and are most often trained as such. They display a clear tendency to increase their internal moment arm length (and therefore their contribution to hip extension torque) with increasing proximity to full hip extension (or even hyperextension). Since there are three major muscle groups that contribute to hip extension (the glutes, hamstrings, and adductor magnus), the point in the joint range of motion at which the gluteus maximus has the best leverage is of utmost importance. Exercises that involve peak forces in full hip extension (or in hip hyperextension), such as hip thrusts and glute bridges, will lead to the greatest gluteus maximus involvement in the production of hip extension torque.

Hip external rotation

The glutes are also hip external rotators, and are sometimes trained as such. It is not entirely clear how the glute hip external rotation internal moment arm lengths change with hip rotation angle. It seems most likely that they increase with increasing degrees of hip external rotation, although some research has found the opposite tendency. This may be because of variation between the regions of the glute muscle, with some regions increasing their leverage with increasing degrees of hip external rotation, and other regions decreasing their leverage with increasing degrees of hip external rotation. Since the gluteus medius is also a key hip external rotator, the point in the joint range of motion at which the gluteus maximus has the best leverage is of utmost importance for exercise selection. Exercises that involve peak forces in full hip external rotation, such as clam exercises against elastic resistance, will therefore lead to the greatest gluteus maximus involvement in the production of hip external rotation torque.

Hip abduction

The glutes are relatively weak hip abductors. In fact, some regions of the glutes actually seem to be hip adductors. Even so, there is a clear trend for the hip abduction internal moment arm length of the glutes to increase with increasing degree of hip abduction. In full hip abduction, most of the glute regions behave as hip abductors, even those that perform hip adduction at other joint angles. In full hip adduction, the opposite is the case, and most of the glute regions behave as hip adductors, even those that perform hip abduction at other joint angles. Since the gluteus medius is also a hip abductor, the point in the joint range of motion at which the gluteus maximus has the best leverage is of utmost importance for exercise selection. Exercises that involve peak forces in full hip abduction, such as clam exercises against elastic resistance, will lead to the greatest gluteus maximus involvement in producing hip abduction torque.

Practical implications

In practice, the gluteus maximus can be trained by hip extension, hip external rotation, and hip abduction exercises. In all cases, the glutes have their best leverage when they are shortest. Thus, training these movements such that peak forces are exerted in full hip extension, hip external rotation, or hip abduction is ideal. Some exercises (such as hip thrusts) automatically provide this feature by virtue of their strength curve. Where it is not provided, elastic resistance can be used to cause the resistance to be greatest when the muscle is shortened.

#4. Working sarcomere lengths

To my knowledge, the working sarcomere length ranges of the gluteus maximus have not yet been measured or even estimated. Even so, given that the gluteus maximus contributes to a greater extent to the hip extension joint action when the hip is less flexed (closer to full extension), and given that the muscle seems to be developed to a greater extent by deeper squats than by shallower squats (but is also very well developed by the hip thrust, which works the muscle at a very short length), it seems likely that the muscle fibers of the gluteus maximus contain sarcomeres that work extensively on the descending limb, and also on the plateau, but not on the ascending limb. In this respect, the muscle would be extremely similar to another large muscle of the lower body, the quadriceps.

Practical implications

In practice, the gluteus maximus can be assumed to work on the plateau and descending limbs of the length-tension relationship, which means that it will experience stretch-mediated hypertrophy when trained at long muscle lengths, but not active insufficiency when trained at short muscle lengths.

#5. Susceptibility to muscle damage

Fiber type

Fast twitch fibers are far more easily damaged than slow twitch muscle fibers, since they are much less oxidative. Thus, it is useful to know the prevailing fiber type of a muscle, because it provides clues about how easily that muscle will be damaged after strength training, and therefore how often it can be trained with a given volume.

Unfortunately, little information exists regarding the muscle fiber type of the gluteus maximus. An early study in cadavers found that the gluteus maximus had an approximately equal (52% type I) proportion of type I and type II muscle fibers. In contrast, a second study involving living patients with osteoarthritis of the hip found that the gluteus maximus had a greater (68% type I) proportion of type I than type II muscle fibers. Consequently, the exact fiber type proportions of the muscle are very unclear, and they may differ substantially between individuals and between muscle regions.

Voluntary activation

Since fast twitch fibers are far more easily damaged than slow twitch muscle fibers, the level of voluntary activation that can be attained for a muscle can also affect how easily it is damaged. The fastest twitch fibers are those that are controlled by the highest threshold motor units. If a muscle can be readily activated to a very large extent, more of its fast twitch fibers will be fatigued (and therefore damaged) than if the muscle cannot be as easily activated. This factor becomes particularly relevant to understand once it is appreciated that the level of voluntary activation can vary substantially between muscles.

Unfortunately, little information exists regarding our ability to voluntarily activate the gluteus maximus. One case study used handheld dynamometry with and without neuromuscular electrical stimulation in order to provide an approximate assessment of voluntary activation in a small number of subjects, and discovered little additional force production as a result of the electrical stimulus in healthy muscles, suggesting that the level of voluntary activation was very high. Nevertheless, short-term strength training programs seem to be able to produce large increases in gluteus maximus activation, which could be taken to indicate that motor unit recruitment is not typically complete, at least in untrained individuals. Alternatively, it may merely indicate that the muscle is not customarily used in such hip joint actions, and that other hip extensors are normally used instead.

Practical implications

In practice, the fiber type and the voluntary activation levels of the gluteus maximus are both very unclear, and therefore it is difficult to predict how easily the muscle will be damaged after strength training.

What is the takeaway?

The gluteus maximus is the largest muscle in the human body. Developing it will likely contribute substantially to increases in whole body muscle mass. It has a wide variety of origins and insertions, and therefore likely fulfils a number of different functions, including hip extension, hip external rotation, hip abduction, and posterior pelvic tilt. The muscle can be subdivided into upper and lower regions. The lower region of the glutes is active mainly in hip extension, while the upper glutes contribute to hip extension, hip abduction, and hip external rotation. Additional subdivisions, such as into superficial and deep regions, may also be present. This suggests that the muscle may benefit from being trained with multiple, different exercises.

The gluteus maximus can be most easily trained by hip extension, hip external rotation, and hip abduction exercises. In all cases, the glutes have their best leverage when they are shortest. Thus, training these movements such that peak forces are exerted in full hip extension, hip external rotation, or hip abduction is ideal. Some exercises (such as hip thrusts) automatically provide this feature by virtue of their strength curve. Where it is not provided, elastic resistance can be used to cause the resistance to be greatest when the muscle is shortened.

For the time being, we can assume that the gluteus maximus works on the plateau and descending limbs of the length-tension relationship, which means that it will experience stretch-mediated hypertrophy when trained at long muscle lengths, but not active insufficiency when trained at short muscle lengths. The fiber type and the voluntary activation levels of the gluteus maximus are both very unclear, and therefore it is difficult to predict how easily the muscle will be damaged after strength training.