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Foot Strike & Functional Movement: Part 2


In the first part of this article series, Foot Strike & Functional Movement: Part 1, we focused on the phases of the walking gait cycle, as well as the unique demands placed on the body during each phase. In this article we will focus on how to properly conduct a walking gait assessment, followed by how to interpret your results and design corrective exercise programming based on the information gathered.

Please note that gait assessment is a skill that requires a lot of practice and time. Simply reading this article will not make you proficient at performing gait assessments; however, this article will build an appreciation for the important role a gait assessment has in understanding your client movement patterns, compensations and injury risks.

Learning Objectives:

  1. To understand the basics of a walking gait assessment
  2. To appreciate how altered gait mechanics impact client results in a gym setting
  3. To learn how to design exercise programming based on a walking gait assessment

As we go through the gait assessment, remember the five sub-phases of the walking gait cycle, as well as the associated demands of each sub-phase. Knowing the normal joint positions and mobility requirements can help identify compensation patterns during each sub-phase. 

Tips for Performing a Walking Gait Assessment

Posterior Gait Assessment

Initial Contact

The first sub-phase we want to assess from a posterior perspective is initial contact. Proper initial contact should be on the outside of the heel with an inverted subtalar joint (STJ). Remember STJ inversion is associated with a rigid and stable foot, which is what we want when contacting the ground.

If initial contact is on the inside of the heel, or on an everted STJ, it is associated with an unstable or unlocked STJ. This interferes with the ability to properly absorb impact forces, load the body spiral and ultimately move efficiently.

Midstance

Midstance is often easier to assess from an anterior perspective, however a person can still appreciate foot position and control of the loading response during the posterior assessment. Note any STJ eversion as the client transitions through midstance. STJ eversion during midstance signifies uncontrolled deceleration of the body spiral, which is similar to eversion during a squat. 

Late Midstance

Late midstance is one of the easiest sub-phases to observe compensation patterns for limited ankle joint mobility.

In Part 1, we discussed how we need at least 5 degrees of ankle joint dorsiflexion as the STJ passes through neutral. Some of the most common compensation patterns you will assess during this sub-phase of gait include:

Propulsion

The final sub-phase of the Stance Phase is propulsion. The optimal plane of position requires dorsiflexion of the great toe in the sagittal plane as this allows for full transfer of kinetic forces.

It is also at this time you want to note any tibial:femoral external rotation as the client enters Initial Swing. Tibial:femoral external rotation is an often misdiagnosed compensation pattern for over-pronation. If you are filming your client’s gait, you should be able to see the moment the tibia external rotates (see  image above).

Anterior Gait Assessment

Initial Contact

Although initial contact is a little more difficult to observe from anterior, I still encourage professionals to appreciate the inversion or eversion of the STJ during this sub-phase. 

Midstance

Control of the body spiral is the easiest to appreciate from an anterior perspective as the client is transitioning to midstance. Poor deceleration or control of the body spiral can be observed as an eversion drop or snap down through the STJ. This eversion drop during midstance often drives the knee into a valgus position.

It is important to note that not all valgus knee rotations are driven from the ground up, but can be associated with a proximal glute weakness. It is your job to determine which is present. If knee valgus is observed during midstance, but STJ eversion is not, then this would be an example of a proximal glute issue. 

Tibial:femoral external rotation should also be noted during the anterior assessment. This would be noted during midstance and the transition into late midstance. In the picture above we can appreciate how the foot is externally rotated relative to the knee - which is going to lead to altered push-off and energy transfer.

Late Midstance

Again note any compensations for limited ankle dorsiflexion and compare these to the observations noted during the posterior assessment.

Propulsion

Note whether the client is pushing off in the sagittal plane with good dorsiflexion of the great toe joint. Compare to what was noted in the posterior assessment.

Lateral Gait Assessment

Initial Contact

During initial contact what we are observing from a lateral view is going to be ankle dorsiflexion (DF) at heel contact. 

The greater the ankle DF at heel strike, the greater the impact forces encountered. Therefore, if you are working with clients or athletes with impact-related injuries such as shin splints, achilles tendonitis or plantar fasciitis these may be related to increased ankle dorsiflexion at initial contact.

Late Midstance

Ankle mobility and the timing of heel rise is easiest observed from a lateral perspective. I advise professionals that the easiest way to observe an early heel lift is related to the position of the swing leg when the stance phase heel begins to lift.

Heel lift should occur when the swing leg is in line or in front of the center of gravity. If the swing leg is behind the torso and the heel begins to lift this would be considered an early heel lift. 

The negative impact of an early heel lift on efficiency is two-fold:

  1. Peak potential energy is not achieved, and
  2. Center of gravity shifts are greater.  

Both of the above reasons cause inefficient movement patterns and increase risk of overuse injury. 

Propulsion

Our focus in the Propulsive Phase is stride length relative to hip extension. Hip extension and great toe dorsiflexion are closely related, which means that if a client has limited ankle or great toe dorsiflexion this will be coupled with a shortening of the stride length.

Any limitation in hip extension (not related to great toe dorsiflexion) would be observed as either an increase in lumbar lordosis or a hip hinge (leaning forward).

Interpreting the Results

After successful completion of the gait assessment the next step is interpreting your results. It is the interpretation of results which will guide you to create more effective corrective exercise and fitness programming.  

Below we will break down the sub-phases of the gait cycle, as well as some of the most common compensations associated with each of these sub-phases. If further assessment is needed this will be indicated, as well as the recommended programming.

Common Compensations Seen During Initial Contact

Compensation: Increased STJ Inversion

Although an inverted STJ is ideal at initial contact, excessive inversion can lead to movement dysfunction and possible risk of injury. Excessive STJ inversion at initial contact is to be avoided for several reasons (and detailed below):

Increased risk of ankle sprains: The risk of inversion ankle sprains on an excessively inverted STJ is intuitive and should be a concern especially for those clients and athletes involved in lateral movements or change of direction.

Impaired shock absorption: Remember that STJ inversion is synonymous with a rigid, locked and stable foot. This means that the more inversion present at foot contact the more rigid the foot will be when encountering impact forces. In order to effectively decelerate and load impact forces our STJ must be able to move through enough STJ eversion (and internal tibial rotation). Clients or athletes contacting the ground on an excessively rigid foot are at greater risk of stress fractures, achilles tendonitis and IT band bursitis. 

Overuse of lateral fascial line: Increased eccentric tension to the lateral ankle and peroneal tendons can lead to overuse of the entire lateral fascial line. Thomas Myers’ Anatomy Trains identifies the lateral fascial line from the insertion of the peroneus longus up along the lateral lower leg, past the knee to include the IT band, TFL and glutes. Due to the integration of the peroneals with the TFL and gluteus above, excessive inversion can lead to altered glute function and subsequent compromise of the hip and knee. 

FitnessRx for Increased STJ Inversion:

To neutralize the excessive inversion you will want to address both the foot and the hips. Start with mobilization via Self Myofascial Release (SMR) of the STJ invertors:

Next, move up to the hip and mobilize (via SMR) the hip external rotators:

Compensation: Increased STJ Eversion

If STJ inversion means rigid and locked, then STJ eversion is going to mean unstable and unlocked. If you notice your client striking the ground on an unstable foot that is already unlocked, proper dissipation of ground reaction forces is going to be compromised. Remember when we discussed how the foot and lower extremity absorbs impact forces? It was the STJ inversion to eversion that drove the body spirals and efficiently loaded impact forces.

If this step is compromised then efficient movement is also compromised. Your goal is to get the client or athlete foot back into a position in which they can strike the ground in an inverted STJ position. 


FitnessRx
for
Increased STJ Eversion:

To neutralize the excessive eversion you will want to address both the feet and hips. For correcting excessive STJ eversion your program will include both mobilization and activation or strengthening.

Start with mobilization of the STJ evertors:

Next, move up to the hip and mobilize the hip internal rotators:

After mobilization, focus on activating / strengthening the STJ invertors:

As well as to activate and strengthen the hip external rotators:

Common Compensations Seen During Midstance 

Compensation: Knee Valgus

The presence of knee valgus during midstance means that there is a lack of control of the body spiral. Since midstance marks the point of peak deceleration, knee valgus typically denotes poor eccentric control of either the glutes and/or the foot invertors (namely the posterior tibialis). 

There are two types of knee valgus which can be observed:

Compensation: Knee Valgus with STJ Eversion

Knee valgus with STJ eversion can be characterized as both a proximal and distal spiral issue. The STJ eversion is often a compensation for weak eccentric deceleration by the foot invertors (namely posterior tibialis). The STJ eversion drives the knee into valgus requiring increased deceleration by the posterior gluteus medius.  

Fitness Rx for Knee Valgus with STJ Eversion:

To correct the knee valgus with STJ eversion, eccentric strengthening is a key component to the corrective exercise programming. Before integrating the eccentric exercises, mobilization and activation must first occur.

Start with mobilization of the STJ evertors:

Next, move up to the hip and mobilize the hip internal rotators:

After mobilization then you want to focus on activating / strengthening the STJ invertors:

As well as to activate and strengthen the hip external rotators:

Finally, begin to integrate the eccentric exercises such as:

Compensation: Knee Valgus without STJ Eversion

Knee valgus without STJ eversion would indicate a proximal glute issue only. All correctives would focus on mobilization, activation and strengthening of the hip muscles only.

Compensation: Tibial:Femoral External Rotation (TFER)

TFER is characterized by an external rotation of the tibia on the femur at the knee joint. This is typically observed at either midstance or during the Propulsive Phase. TFER forces the client to push-off in an altered position which stresses proper foot alignment and creates a counter movement of the body spiral.

The muscles which are typically over-active in TFER include:

FitnessRx for Tibial:Femoral External Rotation​:

To correct for TFER, it again involves mobilization followed by strengthening. 

Begin with mobilization of:

After mobilization, progress to strengthening the muscles which will begin to de-rotate the TFER:

Common Compensations Seen During Late Midstance

Compensation: Abductory Twist

The abductory twist (cigarette twist) occurs as the foot is attempting to move through the ankle joint while the STJ is in a neutral position. A limitation in ankle dorsiflexion will create this compensation mechanism. 

Every time the foot abducts there is an activation of the hip external rotators, namely piriformis. 

FitnessRx for Abductory Twist:

To correct for the abductory twist the focus should be on restoring proper ankle joint dorsiflexion. Focus on mobilization of both the soleus and gastrocnemius. 

Compensation: Early Heel Lift

Another common compensation for limited ankle dorsiflexion is an early heel lift. This early heel lift causes the client to enter Swing Phase too early, which disrupts efficient movement but also places the adductor longus at increased risk of overuse injury. 

In those clients or athletes with a true limitation of ankle dorsiflexion, barefoot work, drop shoes and midfoot-strike running should be avoided as this increases the stress placed on the achilles tendon.

FitnessRx for Early Heel Lift:

To correct for the early heel lift the focus should be on restoring proper ankle joint dorsiflexion. Focus on mobilization of both the soleus and gastrocnemius.  

Common Compensations Seen During Propulsion

Compensation: Altered Push-Off

Altered push-off can be the result of limited ankle mobility, poor deceleration of the body spiral, STJ eversion at heel strike or STJ eversion on relaxed stance. This common push-off position compromises the activation of the plantar fascia, the efficiency of gait and elastic recoil at push-off. 

Without correcting push-off, gait can never fully be optimal.

FitnessRx for Low Gear Push-Off:

To correct for a low gear push-off we need to go back to what is driving this compensation pattern in the first place. Is there limited ankle mobility? Is there tibial:femoral external rotation?

The answer to these questions will determine how to address your corrective exercise programming. See the above compensations for the appropriate FitnessRx programming.

Conclusion

As you begin to implement gait assessment into your movement assessment protocol I encourage you to start by appreciating a few key elements of the gait cycle. For example, watch your client’s ability to decelerate through midstance and compare this to how they squat and land from a jump. You will most likely begin to find the similarities in movement and compensation patterns.

In addition, be patient with the learning curve associated with performing and interpreting gait assessment. There are many great resources available to help further understand the concept of the human gait cycle. Remember that as the most functional (and most common) movement that we do every day, walking is the foundation to many other movement patterns our clients perform during their workouts. If you can help correct compensations during their gait, you will ultimately improve their results when working out!