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2.2 OP mechanics in detail

1. Osteitis Pubis: an introduction
1.1 Symptoms and Stages of Osteitis Pubis
1.2 OP Diagnosis guide
1.25 Should I get a MRI/CT/Xray scan for OP?
2.0 Overworked Adductors: The true cause of OP
2.1 Rest: The worst treatment for OP
2.2 OP mechanics in detail
3.0 Faulty firing patterns: Weaknesses that cause OP
3.1 The Deep Front Line
3.2 Causes of OP: Weak arches
3.3 Causes of OP: Weak glutes
3.4 Causes of OP: Poor core activation
3.5 Causes of OP: Dysfunctional pelvic floor and Sacroilliac Joint
3.6 Causes of OP: Dysfunctional oblique chains
3.7 Causes of OP: The balance and coordination system


Refresh your understanding:

  • Chronic overuse of your adductors leads to degeneration (Osteitis Pubis).

  • Biomechanics, the ways you move, are at the heart of Osteitis Pubis.

  • You have dysfunction and weakness in the firing patterns of your body. These faulty firing patterns change the way you move, causing you to overload and overuse your adductors, creating your very own OP mechanics.

  • Fixing OP will involve altering/correcting these faulty firing patterns and correcting your OP mechanics to prevent overloading your adductors.

  • Rest and treatment alone cannot heal OP because it does not change your  particular faulty firing patterns/OP mechanics.


OP mechanics is a term we use to describe the biomechanical conditions, the very movement patterns that overload the adductors and cause Osteitis Pubis. There are 5 specific OP mechanics;

Each OP mechanic is a biomechanical pattern, a certain way that you move your body. We are interested in the consequences of these mechanics. What does having a ‘hip drop’ mean to your body?

The 5 OP mechanics fail to stabilize different joints as they collapse away from the ‘centre of your body’:

  • Hip drop – the pelvis collapses to the side.

  • Over pronation and supination – the ankle collapses in or rolling out.

  • Knocked/bowed knees – the knees collapse either out or in.

  • Locked SIJ – impinges on/prevents the rotation of the pelvis.

  • Anterior pelvic tilt/sway – the pelvis tips or shifts forwards or backwards, away from the centre.

As these joints buckle under movement they twist, rotate and collapse, increasing the stress and load (‘whiplash’) on the joint. If left unchecked this stress will strain ligaments, stress bones and lead to arthritic changes/degeneration to the surrounding joints. The ‘collapsing’ of these 5 mechanical flaws must be controlled somewhere (the adductors) to avoid significant structural damage to the body.

Fixing OP is the process of strengthening your body to correct these flaws, removing the excessive load and pressure on your adductors.


In our OP development diagram we list 6 functional systems which are dysfunctional/weak in OP;

  • Weak arches

  • Weak Glutes

  • Weak Core

  • Locked SIJ/Pelvic Floor

  • Weak Oblique chains

  • Poor Balance

It is the weakness and dysfunction of these systems which cause each OP mechanic and their associated ‘whiplash’.




Walking and running involve lifting and balancing on one leg at a time. This is challenging as you are essentially doubling the weight on each leg as you step. The pelvis needs to stay neutral to prevent twisting, turning and damaging the hip.


A hip drop occurs when faulty firing patterns prevent the body from stabilizing and controlling the pelvis. You fail to maintain a neutral pelvis once the foot leaves the ground. This causes the hip to twist and rotate as the pelvis collapses towards the ground. You see a hip drop when you look at someone from either the front or back.


The shift in pelvic position also places strain on the adductors because the pubic bone drops along with the rest of the pelvis. OP patients use their adductors to help control this change in pelvic position. Shifting the pubic bone increases the tension/load on the adductors, asking them to compensate for the hip drop from a disadvantaged position.

Obviously this places an extreme workload on the adductors.



Ideally your knees should sit aligned over your toes. Knocked knees are when your knees sit inside of your toes. Bowed knees are when your knees sit outside your toes. Whether knocked or bowed, the alignment between the ankle, knee and hip is disconnected.


This loss of alignment prevents load from being evenly and smoothly transmitted up the body. As you walk/run/jump your knees will either collapse inwards or outwards. The adductors will attempt to control this increased pressure. Unfortunately the loss of alignment places them in a less than ideal position to attempt to control this and the adductors begin to break down, leading to OP.

What if my bowed/knocked knees are structural? Do I need surgery/orthotics to fix my OP?

No human body is perfectly symmetrical. Yes, knocked and bowed knees can be caused by the shape of the tibia or femur, but you can still fix your OP. Bowed legs encourage your knees to roll out and knocked knees encourage your knees to roll in, but that doesn’t mean they have to.

When we consider bowed/knocked knees we are interested in their effect as you are moving. Does your body control the knee, or does it collapse inwards/outwards as you walk?

If you have structurally bowed/knocked knees you’ve had them your whole life, but you haven’t had OP your whole life. Your body has developed muscular strength and firing patterns to accommodate them. In the past your own personal mechanics were adequate to control this issue.

Are OP and other knee/ankle/hip related injuries more likely? Absolutely. But fixing OP is about strengthening and correcting those faulty firing patterns, so they can safely stabilize and control your body. If you have structurally bowed/knocked knees you will simply have to be more diligent in your rehab to ensure you have this issue in check.

You do not need surgery, orthotics or any other extraneous, structural change in your body!

Note: Many people think that this condition is structural but usually this is not right or the structural issue is too slight to influence the mechanics. True structural knocked/bowed knees are extremely uncommon.



The ankle is designed to pronate. Pronation is when the ankle rolls in slightly allowing the force/load of your foot strike to be safely absorbed up the inside (thickest part) of your calves and through the center of your body. Pronation is healthy and necessary. The problem arises when we either pronate too much or not enough.


Over pronation is when the ankle joint collapses inwards. Over pronation is often associated with knocked knees as the knees follow the ankle inwards. This increased rolling inwards/collapsing is out of control, increasing the likelihood of damaging ligament, joints and tissues in the ankle, knee, hips and lower back.


The adductors attach to the entire length of the femur. They will attempt to control the rolling in of the ankle by bracing and limiting the movement of the knee joint (through the femur). However they are in a poor position to achieve this. The adductors will over contract and brace in an attempt to exert control over the ankle joint from a distance.

Over Supination

Over supination is the opposite. The ankle fails to roll in and absorb load at all. This forces excessive load and strain towards the outside of the body to the outside of the knee, ITB band, hip joint, lower back, rib cage and shoulders. Whilst uncommon, over supination is usually a more significant condition than over pronation.


The adductors sit on the medial (inside) of the body. The ankle is failing to roll inwards, allowing the load to ‘jar’ up the outside of the body. The adductors, sitting on the inside, brace and contract in an attempt to pull this load back towards the inside of the body. Again unfortunately it is in a poor position to achieve this goal, so they over contract, over work and develop OP.

Isn’t Over pronation/Supination structural? Don’t I need orthotics?

The human foot is an incredible machine. Constructed of 26 floating bones it is designed to change its form to mould to the shape of the ground. It has a set of strong fascial connections, ligaments and muscles called the deep toe flexors. These muscles and fascia are designed to draw, lengthen and control those floating bones.


Your deep toe flexors control your pronation. If you over pronate or over supinate it is because you have dysfunctional deep toe flexors and their surrounding fascia.


Orthotics may prevent you from over pronating/supination, but they do not teach/encourage your foot muscles/fascia to function correctly. If anything, orthotics make your feet lazy. You need those foot muscles/fascia to engage to help absorb and control the load of your body as your foot hits the ground.

The load of your foot strike has to go somewhere. If you wear orthotics you may ‘shunt’ the load out of your ankles and knees, but this often just sends the load straight into your hips, spine or even shoulders. Orthotics exacerbate OP in some patients!

If you are thinking about purchasing orthotics to correct your OP take a moment now to read:



Observed from the side, an Anterior pelvic tilt (APT) sees the front of the pelvis dip lower than the back. As the pelvis dips it drags the stomach forward. The spine follows the stomach as it protrudes forward, exaggerating the curve in the spine.

APT Increasing the pressure in your spine and pubic bone


Look closely at the images. As your pelvis tips forward into an APT, the weight of the pelvis tips straight towards the pubic bone. With this change in orientation the entire load of your upper body is now aimed straight at your pubic bone.

Also the exaggerated curve in the lower spine increases the pressure on vertebrae, discs, ligaments and muscles of the lower back. An APT is a common cause of lower back pain.

APT= pulling pubic bone apart

The dipping of the pelvis also has a direct effect on the pressure/load distributed into the pubic bone. Your rectus abdominis attaches to the top of the pubic bone. As you tilt, your stomach pushes forward, stretching and straining your 6 pack. This stretch increases the tension/pull of your 6 pack on top of your pubic bone.


Your adductors attach to the bottom of your pubic bone. With an APT you now have tight adductors pulling your pubic bone down, and overstretched abs pulling your pubic bone up. You’re essentially pulling your pubic bone apart! This plays a large role in the high incidence of sports/abdominal herniations OP patients present with; their rectus abdominis (6 pack) is essentially pulling off the bone.

Tight hip flexors amplifying OP

Most people are aware of the connection between sitting, tight hip flexors and lower back pain. This is because tight hip flexors increase an APT. In the case of OP, as your hip flexor tightens, this amplifies the stretch on your abs, overloading your pubic bone. OP patients who present with lower abdominal symptoms often suffer from significant APT issues.

Anterior Pelvic Sway (APS)


An Anterior Pelvic Sway (APS) is a similar condition to an APT. Instead of the front of the pelvis dipping forward, the whole pelvis simply shifts forward.

In an APS the hip flexors do not play a dominant role. The pressure on the top of the pubic bone from the rectus abdominis/6 pack is not as great. However the knees are likely to hyper extend, and it’s  more difficult for the body to control and correct over pronation and knocked knees. The Sacroiliac Joint becomes locked. It combines to increase the demand on the adductors, increasing the effects of your OP.

Anterior Pelvic Tilt/Sway = turned out feet


Both an APT and an APS shifts the position of the pelvis, which impinges/narrows the space for the hip to move in its socket. In response to this ‘jamming’ the body will turn out its feet, attempting to create more space in the hip socket. Unfortunately by turning out your feet you are also stretching your adductors.

Every step you take with your feet turned out is over stretching and literally sheering your adductors from the bone!


Pelvis tilting, dropping and swaying amplify the effects of OP. What happens when your SIJ is locked and immobile?


The sacroiliac joint (SIJ) is the connection of each side of the pelvis to each side of the sacrum (and therefore spine).

Wanting extra stability we can wedge the two sides of the illium strongly into the sacrum at the back. This locks our SIJ firmly into something we call ‘form closure’. In its closed position the SIJ is essentially ‘unbreakable’, securing your spine at the sacrum base.

A ‘locked’ SIJ prevents rotation of either side of the pelvis and creates a rigid immobile pelvis, useful when lifting, but not when moving.

Walking/running/squatting all need a mobile SIJ

Unfortunately movements such as running, jumping, squatting, changing direction all require a mobile, unlocked pelvis. If the SIJ remains locked during these movements the body will try to compensate to find extra mobility. Common patterns are twisting and rotating the spine and rib cage, over stretching from the hip joint and over extending the knees. All of these actions overload your adductors.

Pelvis locked…. Just move your hips/knees instead.

The two most common compensation patterns are:

  1. Knees drive forward


In a squat the pelvis needs to rotate and move backwards, transferring the load into the glutes. Unfortunately a locked SIJ prevents this. To squat, most OP patients will rely on driving the knees forward, often past the toes. The adductors and quads, responsible for stabilizing the knee, become overloaded as they try to control the excessive knee movement.

The increased load on the knees often exacerbates/amplifies the effect of bowed/knocked knees as the knee joint buckles.

2. Pelvic twists/sways


To walk, each side of the pelvis rotates in a different direction (front leg pelvis must rotate forward, back leg pelvis must rotate backwards). A locked SIJ cannot do this so OP patients often twist/turn or sway their entire pelvis to compensate. This increases the instability and load on the lower body, and the adductors respond.

Pelvic Floor = muscle that locks the SIJ

Pelvic floor contraction braces, tightens and locks the SIJ in form closure. It’s the over contracted pelvic floor which lies at the heart of your locked SIJ/Pelvis.


The pelvic floor shares significant fascial connections with the adductor muscles; they can almost be considered the same muscle.

The pelvic floor and adductors mirror each other. When you brace from your adductors you automatically brace your pelvic floor and vice versa. By constantly bracing and locking your pelvic floor/SIJ you are constantly bracing and tensing your adductors and increasing the tension/load on your pubic symphysis.


You really cannot resolve OP by trying to isolate and correct one OP mechanic. You need to engage in full body, functional rehab that addresses and strengthens your ‘core muscular/fascial chains’.

Non-OP patients can present with individual flaws such as a Hip Drop. But it’s the combination of all 5 OP mechanics that creates the imbalances that overload your pubic bone, adductors and lower abdomen. Without the combination of these imbalances the adductors wouldn’t get overloaded and you wouldn’t have OP.

Let's go through a couple of examples of how this occurs;

Example 1: Weak arches causes over pronation, leads to knocked knees, an anterior pelvic sway and hip drop.

  1. Over pronation is the rolling/collapsing of the ankle. The top of the ankle (the tibia) collapses inwards.

  2. This encourages the bottom of the knee (the top of the tibia) to collapse inwards as well, leading to knocked knees.

  3. To compensate for the knees collapsing in, the femur rotates sharply outwards causing the hip to externally rotate in the socket.

  4. This external rotation reduces the tension on the hip flexors, encouraging the pelvis to sway forward into an Anterior Pelvic Sway (APS).

  5. The APS jams the Sacroiliac Joint (SIJ), preventing the pelvis from rotating correctly.

  6. To compensate the pelvis drops/rotates down, causing a hip drop.

Example 2: Poor core activation and glute weakness causes a hip drop and an APT, leads to bowed knees and over pronation. Remember that the ‘deep core’ and the glute muscle group control and stabilize the pelvis during movement.

  1. Poor core activation prevents proper stability of the spine and pelvis.

  2. The hip flexors tighten to compensate and stabilize the spine, pulling the pelvis into an APT.

  3. The APT rotates the pelvis forward, shifting the hip to the back of the socket.

  4. This shortens the glutes, preventing them from firing to stop a hip drop.

  5. As the hip drops it forces the load towards the outside of the body,encouraging the knee to rotate outwards into ‘bowed knees’.

  6. The bowed knees force the foot to land on the extreme outside.

  7. This creates a stone at the top of the mountain effect – as the ankle naturally rolls/pronates inwards upon foot strike it gathers so much speed that it rolls into an over pronated position.

It all works together.

In both situations each OP mechanic affects and is affected by another.

You could try to address one aspect, such as over pronation, but an APS encourages knocked knees,which causes the knees to rotate internally…

To fix over pronation you need to externally rotate (supination) the top of the ankle joint (the bottom of your tibia). Unfortunately knocked knees are internally rotating the bottom of your knee joint (the top of your tibia). Your tibia can only move in one direction so your attempts to correct your over pronation at your feet will be undone by an APS in your pelvis…


Confused…. Worried…Well don’t be! Welcome to what makes OP so difficult. There is not one specific, silver bullet cause to OP. You have a collection of weaknesses that come together to make this disorder. Fixing it involves fixing your whole body, strengthening the core fascial/muscular chain through whole body, functional rehabilitation. Any other type of rehab will simply have you going round in circles.


Fortunately engaging in whole body, functional rehab is a lot easier than trying to figure out the exact cause of your OP. You can spend all day chasing the problem, or you can start working on the solution!

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