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The set of symptoms known as sciatica can be brought on by a number of factors, including poor posture associated with a tight piriformis muscle. Merrin Martin offers some advice on managing a tight piriformis and explains why so many trainers experience sciatic episodes.

The piriformis muscle is a very hard working muscle required for daily function and movement. A number of factors, however, can alter the tension on the piriformis muscle, ultimately resulting in episodes of pain with sciatic symptoms.

What is sciatica?

Sciatica is a set of symptoms including lower back or buttock pain, pins and needles or numbness that may be caused by general compression or irritation of one of five spinal nerve roots (L4,L5,S1,S2 & S3) that give rise to each sciatic nerve. Typically, the symptoms are only felt on one side of the body, with the pain occasionally radiating posteriorly down the leg to the calf muscles.

Common causes of sciatica include lumbar disc injury, osteoarthritic and degenerative disc disease, pregnancy and poor posture associated with a tight piriformis muscle. Sciatica symptoms can result by overloading the piriformis muscle, causing compression of the sciatic nerve as it leaves the gluteal region. Let’s look more closely at the piriformis muscle.

Anatomy of the piriformis muscle

The piriformis is a postural muscle and is required to contract minimally for most of the day. It is part of the deep lateral rotators of the hip, along with the quadratus femoris, gemellus inferior, gemellus superior, obturator externus, and obturator internus. Actions of the piriformis muscle include laterally rotating the femur with hip extension (i.e. in standing up straight or lying prone) and abducting the femur with hip flexion (i.e. in sitting postures or squatting).

Abduction of the flexed thigh is very important in the action of walking, as it shifts the bodyweight to the stance leg, which keeps us from falling, and improves balance when standing on one leg. The piriformis muscle has many additional functional roles, including assisting the posterior oblique chain (gluteus max and latissimus dorsi) in stabilisation of the sacroiliac joint, in stability of the hip joint and in assisting healthy function of the pelvic floor.

Reasons for a shortened piriformis muscle

A stiff or shortened piriformis has significant ramifications on function, resulting in problems during walking, sitting, stair climbing, squatting and lunging.

A tight piriformis can result from:

1. Not correctly stretching the piriformis and only stretching the gluteus maximus muscle

Personal trainers do a great job of including the gluteus maximus stretch in classes and in sessions, however, many do not change the angle of the leg when in hip flexion to increase the stretch on the piriformis muscle. The knee must be brought across the midline of the body, bringing the hip into flexion and adduction and lateral rotation to feel the stretch deep into the piriformis muscle.

2. Weak core awareness and control (not being aware of holding pelvic floor, or activating transversus abdominus (TrA) while performing advanced abdominal exercises)

It is one thing to activate your transversus abdominus and pelvic floor muscles when lying fully supported in supine, but it is much harder to stand with a weighted load and perform dynamic exercises while maintaining a good contraction of the pelvic floor muscles and core. I often see a client or trainer set up perfectly to start an exercise, only to switch off the core and excessively contract their movement muscles as soon as they begin the exercise. It is essential to keep the core switched on throughout any exercise: doing so helps reduce load on the piriformis.

3. Weak pelvic stabilisers (lack of co-contraction of specific contralateral muscles attaching to the pelvis)

Muscles such as gluteus medius, adductors, obliques, gluteus maximus and latissimus dorsi are essential to a stable functioning pelvis. These muscles provide force closure to the pubic symphysis (groin) and sacroiliac joints. A good understanding of how to activate these pelvic sling systems is essential for reducing the load on the piriformis, and along with it the risk of sciatic symptoms.

4. Tight hip flexors

As trainers we are always bending over our clients in a shortened hip flexion position. Furthermore, we regularly include quadriceps stretches into our programs – but how often do we stretch out the psoas major muscle? Tight hip flexor muscles can increase the lumbar lordosis in our postures and increase tightness in the erector spinae and piriformis muscles. In addition, this lordotic posture tends to favour the use of the hip flexors as the preferred muscle to stabilise when performing exercises such as plank or push ups. It’s a vicious cycle – and combined with a weaker core, the likelihood of a sciatic or low back pain episode increases significantly.

5. Hyperactive pelvic floor muscles

It is common for athletes or highly trained individuals to have pelvic floor muscles which cannot relax. Using a real time ultrasound machine in a clinical setting enables me to view these muscles as they work. Some clients with constantly contracted or hyperactive pelvic floor muscles take a lot of relaxation or down training of these muscles in order for them to function in the normal phasic manner. A state of constant contraction will increase the tension in the piriformis muscle, further increasing the risk of sciatic or low back pain.

The piriformis muscle is critical to safe and effective daily function. An awareness of the factors that can alter the tension on the piriformis, ultimately resulting in episodes of pain with sciatica symptoms, will enable you to prescribe preventative exercises to clients.

Merrin Martin, BAppSc (Physio)
Merrin is the founder of Active Anatomy Physiotherapy & Health Professional Workshops. She is an experienced physiotherapist, exercise scientist and qualified Pilates instructor. An APA, ESSA and Sports Physiotherapy member, Merrin is considered an expert in her role as a health educator and developer of specific exercise programs. To contact Merrin or the Active Anatomy team call 0414 423 744 or visit

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