Returning to Running Post Injury: Part 1 – The Injured Runner

Okay, the time has come, you have a patient who wants to return to running. It’s complicated but this blog will help to guide you through the process. It will be split into the two most common populations you will see in clinic; Part 1 – being the “Runner” with an overuse injury, and Part 2 – the Field / Court sport athlete returning to running.

The common injuries and likely underlying mechanisms in these cohorts will vary on either end of the spectrum from acute trauma (e.g. field / court athlete) to chronic overuse (e.g. runner). Having strategies to work on either will be useful and somewhat transferable to any individual presenting with goals of returning to run.

Let’s get into it!

Return to running after a chronic overuse injury

For a deep dive into this topic I would suggest watching Dr Rich Willy’s Masterclass on ‘Restoring Load Capacity in the Injured Runner’ (1). As so eloquently put by Dr Willy, “Running overuse injuries are always a training load error and biomechanics just dictates where it’ll show up” (1).

This statement outlines the likelihood that a running related overuse injury will manifest as a mismatch between applied physical load and the tissues load tolerance / capacity. This type of presentation can show up anywhere up to 3 weeks post initial error if this balance between load and capacity isn’t restored (1).

Biomechanics, as in the relationship between running technique and tissue ability to resist force, will dictate the site of overuse. This is why the same running technique in different people could result in a bone stress injury, patellofemoral pain, greater trochanteric pain, or no pain, depending on the person. Again, the onset of pain / injury must be preceded by a training load error, and is not the fault of biomechanics alone. In our analogy, if I just listened to my beautiful wife and kept the washing loads small, it wouldn’t matter how I threw the washing in, even if I was objectively wrong, nothings going to break.

Training load

The research is lacking regarding the best way to quantify training load error, with the acute to chronic workload ratio being the most predominant (2). However, the utility of calculating the ratio and predicting injury has since been called into question (3). Levels of strength, repeated sprint ability, and cardiovascular endurance are all confounders in acute:chronic workload models, with more robust athletes less likely to be affected by load spikes (4). Therefore, it just serves as a framework from which to examine training load. The basic premise is that the acute training load of any session or training block, should not be exceedingly higher than the adapted training capacity.

I know.. Rocket science huh!

This is often tracked as session Rating of Perceived Exertion (RPE) X time. The other way to track this in runners is in the number of kilometer’s run. I like to also incorporate Greg Lehman’s cup analogy, where pain / injury may occur once the cup is overfilled with a variety of biopsychosocial stressors. This takes into account the impact of non physical stress on the ‘load vs capacity’ relationship (5).

These all also fit well within the ‘Envelope of Function’ model that Scott Dye used in his seminal paper, where tissue breakdown will only occur once supraphysiological loads are applied in an acute event or from high frequency of lower impulse loads (6). As they say, “all models are wrong, but some are useful”, and I find these models easiest to understand what is actually meant by training load error.

Returning to running

There are a few strings we can use here as clinicians to help restore running load capacity:

1) Increase the Capacity of the Overloaded Tissue Through Training.

This requires knowledge of the underlying tissues involvement in the patient’s specific context, it’s stress and recovery tolerance, and then adjusting training perimeters of strength, plyometric and running work to eventually meet the load required in the specific running tasks (e.g. 2.5-3 X bw in jogging at 11-13 km/hr) (7).

2) Decrease Acute Loading Through the Overloaded Tissue.

This is done through technique modification and using aids that distribute force differently. A basic treadmill running gait analysis is useful here as the forces and technique are similar to running overground (7). After the assessment, put in place your intervention, for example:

• Cue: “hit the ground quietly” to decrease heel strike on initial contact
• Tempo: adjust stride cadence with a metronome, eg +20% quicker than baseline stride frequency to manipulate stride length and knee vs ankle forces.
• Aid: taping / orthosis for foot posture

Don’t forget to reassess subjective and objective results of your intervention (8).

3) Graded Exposure to Running Loads.

This usually involves setting an acceptable pain target for a running session and length of time acceptable at this pain level, with either a kilometer or time target. There are many effective programs to achieve this. Usually split into either interval or continuous training.

• Interval example: Run 1km or 6 mins >2/10 pain, walk for 500m or 6 mins 0/10 pain for a total of 4km. Progress run distance and decrease walk distance weekly as tolerating. Target paces for the work and rest can be useful to set intensity as well.
• Continuous example: Run 4km in a specific time or rpe and within target pain limits. Progress distance and speed weekly as tolerating

Clinical pearl

It’s important for our runners to get a win on their initial RTR (return to run). To build confidence and set an outcome measure, I like to use a pain limited version of a traditional Maximal Aerobic Speed (MAS) test (e.g. 1.2km or 5 minute time trial). This allows me to view their first run and help them understand pain limits as well as giving me actionable data such as tolerable average speed or volume at pain onset for programming. See the below video for an example of this in practice.

Important consideration

With many endurance athletes such as runners and triathletes, running not only takes up a large portion of their training, but also their identity. They have to believe you understand the training volumes (sometimes 50+km a week) it takes to reach their goals and know that you have a plan to get them back there (1). Giving thorough advice and education around the return to running process along with the benefits of general strength and conditioning in restoring load capacity is key to avoiding the all too common boom bust cycle of deconditioning and chronicity many face.

When increasing from current tolerable load to goal load many strategies are used but none have been shown to be uniquely effective in decreasing risk of reinjury. The following are worth considering as starting points but individualisation and adaptability are key (1).

1. The 10% Rule: Usually not a bad spot for people running middle type distances each week 10-30km. Obviously limitations exist at either high or low weekly running loads.
2. The Golden Ratio: Increasing distance / intensity by 0.8-1.2 times / week. Again, there is no unique benefit of this ratio but you will see it commonly (2).

Further consideration should be given to the surface, the shoe type, its impact on ground reaction forces and stance times. Ground reaction forces differ slightly between surfaces, but the time in stance phase seems more significant. Concrete surfaces usually produce shorter stance phases and higher impulses compared to tarmac or artificial turf (9). This can be offset by selecting a higher heeled shoe to increase stance time if concerned about impulse sensitive conditions (e.g. tendinopathies).

The final consideration is the use of running mechanics drills to get a specific load into the target tissues of running. These can be a great way to keep the runner engaged in the rehabilitation process as they are directly related to the goal task. There are a multitude of drills that you can choose from. Just clinically reason which drill is most appropriate based on your patient’s context. The below video shows an example of some of my favorites.

Wrapping up

Okay, so that’s the general process for overuse-related pain / injury in endurance athletes. Remember to check out Dr Rich Willy’s Masterclass for a more in-depth look at this topic.

Part 2 of this blog series will cover my favourite topic – returning the field/court sports athlete to running. Remember, there will be some crossover between populations and strategies, making it practical for whatever level your patient is at.