Strength Imbalance and Running Injury Part 2

This post is part two of a series. If you missed part one, be sure to go back to check it out from back in May 2017. In part two, I take a look at a few more strength imbalances that I find frequently in my running patients. Make no mistake: this article applies to all athletes that run regardless of sport. 

As mentioned in the previous article, too many clinicians place a solitary focus on fixing areas of injury locally, at the site of pain. This is often insufficient. Identifying any contributory strength imbalances is important for true resolution of the problem. It also pays dividends in prevention of injury recurrence, which is the real uphill struggle for runners.

Some may question why I use the term muscle imbalance, when many of these read as a simple weakness issue. The answer is simple: muscles work in systems and every muscle system is balanced by an opposite muscle system. Isolated strength testing does not always reveal weakness in athletes, but when functional movements are analysed, the movement patterns tell a story. 

The answer to the question of 'how much strength is really needed for running' is variable among runners. Not every car needs a V8 engine, but those that do, will require a chassis and transmission that are in accordance. The wrong 'transmission' may be perceived as weak or faulty, but maybe it’s just not the right one for that particular vehicle.

The same can be said for runners and other athletes. Does a sprinter need more abdominal strength than a first time marathoner? Who needs greater ankle strength: a dancer or a soccer player? These things are all task specific and related to how the other muscle groups perform.

#4 Hip Extensors (Glute max, hamstrings) and Abdominals (rectus abdominis, external oblique)

‘Core weakness,’ a real buzzword in recent times, is often used ambiguously. In this case, the implications are more clear and direct. I most frequently see core weakness in two types of runners. The first type are those with generalized weakness in the abdominals. The second type are those who produce lots of power through the legs, but with limited control.

In running, the function of core stabilization is to maintain a relatively consistent positioning of the pelvis during all phases of the gait cycle. The pelvis is expected to move minimally in healthy, strong runners, but a complete loss of stability results in excessive, unpredictable movement dictated by what’s happening in the legs and trunk.

Because elasticity is such an important part of energy conservation and power production in running, a loss stability in the pelvis results in altered firing patterns in most muscle groups...let's just say all muscle groups.

A basic example of this is the amount of hip extension at toe-off (how far behind your body your knee extends, just before your toe comes off the ground.) If your abdominals stabilize the pelvis, a greater level of elasticity will help drive the knee/hip forward. If stability is lost, runners tend to fall into an excessively arched lower back: everything changes.

A strong core is able to maintain neutral spinal cures during maximal force production. 

A strong core is able to maintain neutral spinal cures during maximal force production. 

Although excessive arching is common, other runners fall into a forward flexed posture, especially on hills and at late stages of a run when fatigue peaks. These runners often have difficulty controlling the knee, resulting in iliotibial band pain (ITB), patellofemoral pain, and low back pain, just to name a few. These runners tend to hit the ground with greater impact (GRF.)

Because assessing someone in my office does not easily lend itself to fatigued states, I notice this imbalance more easily when bringing runners to a pace somewhere between their 400m and 800m pace. At this power output, stride length should open up, and a maximal load is imposed on the abdominals for core stabilization.

Seeing this imbalance in the opposite direction, wherein the abdominals overpower the glutes is not nearly as common. In these cases, runners often utilize a fast cadence naturally (180+ steps per minute). These runners typically increase their cadence in excess of 190 steps per minute when they approach race pace, which may be unproductive. 

This pattern can be particularly difficult to decode, as it looks near identical when there is excessive tightness in the hip flexors/abdominals or when hip range of motion is limited. In either case, the decision to make any major changes should be approached with caution unless there is intent to rehab an injury.

 #5 Quadratus(lumborum) and Gluteus Medius

Sidebending of the trunk is typically thought of as a combined movement of the pelvis and the opposite hip joint. In sidelying hip abduction, you can easily see these two areas working together, but in the presence of an imbalance, the quadratus can try to pick up the slack for a lackluster gluteus medius.

Despite being one of the most common imbalances seen in geriatrics (stroke, hip OA), its presentation in runners can be difficult to identify, presenting somewhat differently. The textbook marker of this dysfunction is the Trendelenburg sign, but this may only be seen while standing or during walking. 

Many fail to consider the implications of an overtly strong and/or tight quadratus that has been working to compensate for said glute med weakness. In chronic presentation of these individuals, I find innominate rotation to be a common problem as well, latent with SI joint pain. 

Innominate rotation can be difficult to understand. We typically think of the pelvis moving as a single unit, however, in truth, there is a minimal degree of asymmetrical rotation that can occur. The easiest way to picture this in your mind is to think of your low back being arched slightly more on one side than the other.

Weakness of the glute med is an equal opportunity strength impairment affecting the young and old alike. 

Weakness of the glute med is an equal opportunity strength impairment affecting the young and old alike. 

Running with an innominate rotation can create an incredibly diverse set of problems that is quite variable among athletes. Many with feel as though they have some central low back pain, some with complain of generalized pain in the posterior hip (hamstrings, piriformis, glute max) and others with have pain in the anterior hip (psoas, rectus femoris.)

Often these runners (myself included) will present to their doctor with diffuse low back or hip pain and be treated for a leg length discrepancy without consideration of the pelvis. This will often make the problem worse rather than better. Often glute med ‘weakness’ will be noted and addressed, but without consideration of the rest of the system.

#6 Peroneals and Arch Stabilizers

Pronation is the transition from the outside of the foot (often the heel) to the inside of the foot, from initial contacts to toe-off. Pronation is a near-magical, multi-joint, multiplane, coordinated movement of the foot, that allows a simultaneous acceptance of high load forces and maintenance of momentum.

Despite its utilitarian nature, even pronation can occur in excess. ‘Overpronation,’ which is an exaggeration of this motion, has been tied to countless running injuries, some of which lack sufficient evidence from research. The role of pronation in running injury is complex, making it difficult to truly say how much is 'too much.'

The majority of pronation is driven actively by the calf, with fine tuning from the peronei (peroneus longus and brevis). In order for the peroneals to do their job well, these muscles work in concert with other muscles including the hallux (great toe) flexors and the arch stabilizers.

The arches must be strong and stable for all of the other parts to function. 

The arches must be strong and stable for all of the other parts to function. 

When these are out of balance, typically the additional pronation overloads the weak arch stabilizers. The arch collapses, the hallux flexors work extra hard to pick up the slack, but it’s too little too late.

These runners often have heavy callus development on the outside of the big toe. They typically complain of plantar (bottom surface) foot pain, which sometime presents as plantar fasciitis but also can present as muscle injury in the hallux flexors. They will often demonstrate difficulty maintaining single leg balance while the toes are in extension, as they grow to become more dependent on the toes for balance.

On the opposite end of the spectrum, those whose hallux flexors are taking on more than the peronei, may present with similar complaints, but also with peroneal pain and dysfunction. The hallux flexors simply aren’t strong enough to control pronation alone and the cumulative weakness, leads to excessive eversion of the ankle during pronation, and excessive loading of the plantar fascia  

These runners can complain of pain in a variety of places from the outside of the foot, behind the outer ankle, and even just below the side of the knee where the peroneus longus attaches to the head of the fibula. Granted the similar mechanical dysfunction and symptom triggers, this can easily pose as IT band syndrome.

Successful resolution of this problem warrants in-depth investigation of contributions from the hips and knees as well. As previously mentioned, overpronation can be complex. Some clinicians will immediately reach for an orthotic insert, additional arch support, or a motion control shoe.

Although there are cases where this is appropriate, there is no evidence that these address the mechanical dysfunction. The majority of these tools address alignment of the heel (calcaneus), but often fail to control the midfoot and especially the forefoot.

Finding the Fix

Identifying these imbalances can be difficult. In part this article is written for a variety of readers, to be useful to all involved with running athletes, whether as a coach, a trainer, a clinician, or simply someone who runs regularly for fitness. Anyone has the capacity to make observations about their running and this information is useful when seeing a PT for help. 

Keep your body healthy and strong, and enjoy every moment of the run. 

Keep your body healthy and strong, and enjoy every moment of the run. 

The information above is hopefully enough to provide some insight and get the ball rolling, although it's not intended to suffice as a complete and exhaustive diagnostic guide. When pain starts to become a recurrent phenomenon during exercise, expert advice is warranted sooner rather than later.

Long term propagation of overuse injuries typically results in more time and effort in correcting them. Whether you spend time on the track, the court, or the field, almost all athletes are runners, and are susceptible to running related dysfunction. If you are experiencing pain or injury, find a running specialist near you and get solutions today.  

Be sure to check out part 1 of this series if you haven't already. Until next time: don't stop moving! 

-Allan