BRINGING SCIENCE TO TREATMENT

Running injury rehabilitation: build tolerance through loading

In the second part of this two-part article, Tracy Ward reviews the best-practice, home-executed loading techniques for runners seeking a return to sport following injury.

 2016 – Kenya’s Cyprian Kotut crosses the finish line to win the 40th Paris Marathon  REUTERS/Benoit Tessier

Returning to running following an injury is a complex process that requires careful planning and monitoring. The most common running-related injuries are medial tibial stress syndrome, Achilles tendinopathy, plantar fasciitis, and patellofemoral syndrome(1). Runners are especially susceptible to repetitive loading injuries due to the chronic nature of training, and the desire to push boundaries regularly. Many runners perform little strength and conditioning work to support their training mileage, and therefore, are at even higher risk of injury.

Return to sport

Runners who begin rehabilitation shortly after suffering an injury can shorten the return to play timeframe, without increasing the risk of further injury(2). This finding suggests that – providing athletes follow a properly structured program – early loading is key to returning runners to their sport. Since running is a year-round sport, athletes may try to rush rehab to meet a scheduled competition. However, they must consider the risks versus the reward – ie is the risk of re-injury worth the potential event achievement? Could exacerbating this injury prevent participation in future events? Runners seeking a return to the road should adhere to the principles of readiness, tolerance, and load progression. A return-to-running program developed by a sports professional can ensure a timely and safe return to running with minimal setbacks.

Readiness to run

Before starting a return-to-running plan, evaluate the athlete for their load tolerance. Conduct a series of tests to gauge the progress of their rehabilitation and readiness to tolerate loading (see table 1). Isolated performance tests lack reliability and validity to serve as discriminative outcome measures because they do not correlate with running. However, they serve as measures of an athlete’s current function; if the athlete fails these tests, running will likely exacerbate the injury(3).


Table 1: Suggested physical tests to evaluate response to progressive loading(4)

Test

Pain Score /10Control (good, moderate, poor)
Normal daily activities
Walk 30 minutes
Single leg stand (10 seconds)
Single leg squat (20 repetitions)
Jog in place (60 seconds)
Jump squats (10 repetitions)
Bounding (10 repetitions)
Hop on the spot (10 repetitions or 30 seconds)

Conduct these tests in the order shown. If symptoms occur or if the pain extends beyond a 3/10, the athlete is not ready to run. Stop the testing and continue with the rehabilitation plan.


Passing all tests in sequence with no or minimal symptoms suggests the athlete can tolerate impact and, therefore, withstand some running load. The primary emphasis of the testing is on the symptom response. Control elements, while possibly contributing to the original injury, do not usually affect running performance. Bear in mind, however, that no test can evaluate running tolerance better than running itself.

Run tolerance

Run tolerance is the distance or duration that an athlete can run with minimal or no pain, and no lasting symptoms the following day. Consider these three factors(4):

  • Symptom response during the run: Pain should not exceed 3/10. If it does extend to 4-5/10, continue with program as long as points 2 and 3 below are adequate.
  • Symptom response over the following 24 hours: Symptoms should return to baseline within 24 hours post-run.
  • The trend in symptoms: Symptoms should improve over time despite progressive running sessions.

Other subjective measures, such as the Borg rating of perceived exertion scale, provide an insight into internal load and the athlete’s perception of their exertion. Excess loading is not just about physical symptoms; high psychological loading negatively affects injury recovery and endurance performance(5). Mental fatigue may result in a higher than normal perception of effort and, therefore, requires close monitoring(5).

Establish run tolerance early in the rehab process because exposure to load builds a tolerance to load, and this load should be reflective of the end functional goal, ie running(2). Run training also develops the physical conditioning specific to running – ie strength, aerobic capacity, and motor refinement that athletes cannot achieve through strength training alone(2). Therefore, despite an injury, athletes may tolerate a bit of running, albeit at a slower pace or for shorter distances. If the athlete has an established run tolerance, they should continue to run (with monitoring) rather than cease running completely.

Finally, early commencement of run training allows the athlete time to build an adequate chronic workload, which reduces re-injury risk and return to sport time. Athletes with a low chronic workload can take significant time to return to pre-injury levels if adhering to the recommended acute:chronic workload ratio of less than 1.5(2). Determine the athlete’s maximum run tolerance and use this as their longest run, with several short runs added in the schedule to build mileage safely without exacerbating symptoms.

Load progression

Add running-specific exercises alongside the injury rehabilitation exercises and running sessions. Target the gluteal muscles, as they play a multifactorial role in running biomechanics. The gluteus maximus is the main driving force behind hip extension, while the gluteus medius controls the lateral stability of the pelvis and the lower limb(6).

Running-specific exercises should include muscle activation, movement control, and strength exercises. Muscle activation exercises are primarily isometric – ie muscle contracts without movement. Begin isometrics at the start of a program to allow activation of the correct muscles and prevent compensation from other muscle groups before heavier loading. Isometric exercises also stimulate blood flow and can have an inhibitory effect on pain; completing these first, therefore, may allow further progression with less pain(7).

Control exercises focus on using the gluteal muscles to control the pelvis and femur position, as well as preventing increased hip adduction or valgus deviation of the knee. Perform control drills before strength work for maximum control without muscle fatigue. Focus strengthening program on building the gluteal muscles, while also activating the quadriceps and hamstrings simultaneously (see table 2).


Table 2: Example exercise program for muscle activation, movement control, and strength.

Muscle activation Movement controlMuscle strength
Isometric wall press (stand side on to the wall with hip and knee at 90 degrees and press into the wall with your outer hip/thigh)Single leg stand +/- challengesForward step-ups
Side planksSingle leg squatDeadlift
Static wall squatSingle leg deadliftWall squat
Banded side steps (loop a band around your feet and take a side step one side and back, then to the other side )Forward lunge stepSide plank
Side-lying hip abduction

During return-to-run training, alter one variable at a time and evaluate the effects. For example, running variables include distance, pace, speed, gradient, or route. Strength training variables such as the number of sets and repetitions, exercises targeting the same group of muscles, end range pulses, and static isometric holds, all contribute to overall training volume. Increase training volume gradually through one of the variables until the athlete peaks and then decrease the amount of work but increase in weight. For instance, perform three sets of eight reps and progress to four sets of 12 reps. Once the athlete tolerates 12 reps, drop the volume back down to three sets of eight reps, and increase the weight. A slow 10% increase in strength training volume in a progressive program reduces the risk of injury(8).

The core formula for running

The benefits of core training in sport include increased core stability, coordination, postural balance, and improved strength in adjacent tissues – all of which reduce the critical joint loads(8). Collectively, these improvements allow the athlete to detect high-risk loading situations, and react accordingly, thus minimizing the risk of further injury. Moreover, a weak core increases the susceptibility of groin and lower limb injuries due to the impaired biomechanical translation of loads from the lower limb through the pelvis and spine(9).

Furthermore, right-side dominant runners activate their core muscles on the right side significantly more than their left creating a muscle imbalance, with overactivity in the right side core musculature(10). This asymmetry is possibly a factor in low-back pain or dysfunction through the pelvis and lower limbs. As running is a symmetrical, bilateral sport, a balanced program to re-train core symmetry is beneficial in preventing or reducing the recurrence of injuries.


Core training exercises for runners

Scissors

Begin with both hips and knees bent to 90 degrees. Engage the lower abdominal muscles by pressing the navel to the mat. Toe tap one foot to the ground. As you bring this leg back to the start position, simultaneously toe tap the opposite foot on the mat.

Crisscross

Rotate to one side, elbow toward knees, back to the middle, then to the other side.

One-leg stretch

Bring one knee to 90 degrees, then fully extend the other leg, lowering the leg toward the floor. Keep abdominal muscles contracted as you place that foot on the floor and extend and lower the opposite leg.

Prone plank

Hold the high plank position and raise one leg up, keeping abdominals contracted.

Swimming

Extend the opposite arm and leg away from the body, keeping the abdominals pressed against the spine and the pelvis level. Perform on opposite side.


In summary

  • Most running injuries occur in the lower limb due to repetitive loading. This chronicity makes returning difficult, and an analysis of load and run tolerance essential.
  • Evaluate readiness to run through a series of progressive tests, from low level to plyometric and high-impact based exercises.
  • Run tolerance should be measured as soon as appropriate to continue running where feasible, and calculated into running schedules.
  • Core training supports the pelvis and lower limbs, as well as developing symmetry as an injury prevention measure.

References

  1. Sports Med. 2012; 42(10):891-905.
  2. Br J Sports Med. 2020; 54(1): 58-66.
  3. Br J Sports Med. 2015; 49(20):1288-1289.
  4. Physio Edge. 2019; https://gallery.mailchimp.com/b48cc8a53156cb666fe720490/files/bb3d7a37-a005-4104-a426-9f06618c0e18/Guide_to_return_to_running_post_injury.pdf
  5. Sports Med. 2017; 47:1569-1588.
  6. J Strength Cond. 2020; 42(1): 60-66.
  7. Br J Sports Med. 2015;49:1277–83.
  8. Br J Sports Med. 2018; 52: 1557-1563.
  9. Sports Med. 2007; 37: 881-894.
  10. BMJ Open Sp Ex Med. 2019; http://dx.doi.org/10.1136/bmjsem-2019-000556
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