Running After A Bone Stress Fracture

Running After A Bone Stress Fracture

Bone Stress Injuries (BSI) are not uncommon in avid runners, track and field athletes, and endurance athletes. As common as they may be, they are still very difficult to deal, hard to identify for the average person, and unfortunately can turn into full-blown bone stress fractures before being correctly identified and treated. In this article, we will discuss exactly what bone stress injuries and bone stress fractures are, what the risk factors are, and prehab strategies to get back to running after a bone stress fracture.

What Is A Bone Stress Injury (BSI) & A Bone Stress Fracture?

Bone stress injuries (BSI) in runners result from the failure of the skeletal bones to withstand repetitive, submaximal forces. BSI can range in severity as well as location, with early injuries showing varying degrees of bone edema on an x-ray versus more advanced stress fractures showing evidence of a fracture line (1). According to an article by Pegrum et al. 2012, “stress fractures occur as a result of overuse injuries to bone, either secondary to bone fatigue or bone insufficiency. Fatigue stress fractures occur when normal bone is unable to keep up with repair when repeatedly damaged or stressed. Insufficiency stress fractures, however, occur in bone that is under normal strain but structurally abnormal because of metabolic bone disease or osteoporosis.”

What Are The Incidence Rates & Risk Factors?

According to an article by Tenforde et al. 2016, “studies suggest the annual incidence of BSI may be greater than 20% in runners and that BSI is a common cause of injury in track and field athletes.” Another group has suggested that up to 20% of sports medicine consultations every year are for bone stress fracture injuries (2).

Research into bone stress injuries and bone stress fractures in regards to running and other sports have identified two groups of risk factors that contribute to these types of injuries. Intrinsic risk factors are those that are inherent to you including your gender, genes, medications you take, nutrition, and your body type and build. With intrinsic risk factors, some of them are non-modifable risk factors meaning you have little to no control over being able to influence them. For runners specifically, intrinsic risk factors are more signifciant to consider for females compared to males as being a female is a risk factor for bone stress fractures.

Extrinsic risk factors, on the other hand, are those that are shaped by the environment you immerse yourself in. In regards to running, this includes your running mileage, your training schedule, the route(s) you take, the surface you run on, the shoes you wear, the pace you run at, and more. Below is an extended list of both risk factor groups

Box 1 From Pegrum et al 2012, “Diagnosis and management of bone stress injuries of the lower limb in athletes.”

Female Triad Athlete

If you’re a runner you’ve likely heard the term – the female athlete triad. This term refers to the presence of low bone mineral density or disordered eating, low body mass index (BMI), and menstrual irregularity or prolonged absence of menses. In females, any of these components increases the athleteโ€™s risk of bone stress injuries and bone stress fractures (2). This is why it is extremely important to do your due diligence as a healthcare professional, a parent, or as a coach when working and dealing with female runners who are experiencing lower limb or even low back/pelvic pain. It takes a team effort to help female athletes when dealing with these types of injuries. It is even more important to consider prehab strategies with female athletes who have had a bone stress injury or bone stress fracture in the past. You can learn more about the female athlete triad by clicking here

What Are The Common Locations?

Common sites for bone stress injuries and bone stress fractures are primarily in the lower body. The common locations include the femur, tibia, fibula, and bones in the foot including the metatarsals, tarsals, and calcaneus (1). Based on the understanding of the biological healing process, knowledge of blood supply to bone in different areas of the body, and the direction of loading on the bone, these locations have been separated into low, medium, and high risk of fracture non-union – meaning the chance of the bone failing to heal unless intervention, such as surgery, is performed.

Common BSI Injuries Created By Chris Johnson PT

Diagnosing Bone Stress Injuries & Stress Fractures

Ultimately the gold standard for identifying and diagnosing bone stress injuries and bone stress fractures is using Magnetic Resonance Imaging (MRI). MRIs are the most sensitive and specific imaging modality compared to normal radiographic images (x-rays) as these images can appear normal for the first few months despite clinical signs and symptoms of a bone stress injury. It typically takes a bone stress injury to fully progress to a bone stress fracture to see changes on a x-ray. With early imaging via a MRI, a bone stress injury can be detected, which can lead to appropriate intervention in efforts to avoid a full blown bone stress fracture and delayed recovery time (2). This is one of the few instances that we support early imaging – if a bone stress injury or bone stress facture is suspected – as this can truly change and dictate the next course of action.

Imaging recommendations should be based on a thorough evaluation of the individual’s demographics, medical history, training history, mechanism of injury, and clinical signs and symptoms. In general, bone stress injuries are initiated by a bone stress reaction and typically present with focal tenderness to palpation at the bone site. Pain is experienced at the bone site with training and physical activity. Progressive bone stress injuries and bone stress fractures will present with pain after activity including pain at rest and pain with simple day to day activities (2).

Bone Stress Fracture Management

Below is a simplified algorithim by Pegrum et al. 2012’s group to understand the steps taken following the identification of a bone stress fracture.

Adopted From Pegrum et al. 2012

[P]Rehab Strategies For BSI & Bone Stress Fractures

There are multiple things to take into consideration in efforts to avoid bone stress injuries and bone stress fractures. It all comes back to analyzing the risk factors, ultimately prehab is based on a needs analysis and the specificity of the activity. If we consider non-modifiable risk factors such as gender, age, unfavorable boney anatomy, and family history of BSI – simply having awareness that you’re more prone to these types of injuries will help you make smarter informed decisions about managing modifiable risk factors. These include…

  • Physical Fitness Level (get fit to run, don’t run to get fit)
  • Training Volume (smart program periodization, cross-training, mileage, intensity, recovery)
  • Nutrition (calcium and vitamin D intake, caffeine intake, smoker, energy availability)
  • Stress (rest, sleep, physical and psychological life stressors)
  • Targeting Strengthening (if you have a history of foot BSI – be sure to include more calf and foot intrinsic strengthening exercises)

We feel confident in saying >90% of the running injuries we see in the clinic are due to training errors. The more educated you are about the physical activity you want to perform and the musculoskeletal risks associated with it, the more likely you’ll be able to make smart prehab decisions for your body.

Return to Running After Injury

So what if you’re already dealing with a bone stress injury or a bone stress fracture? How do you get back to running? Below we will identify what we believe are the appropriate steps to manage these types of injuries.

  1. Accurate Diagnosis – consult with healthcare professionals that have experience with treating runners. Work with someone like a physical therapist and an orthopedist to assess you and ensure early and accurate identification of a bone stress injury or bone stress fracture as better results are associated with earlier identification of these types of injuries.
  2. Activity Modification – The sooner these types of injuries are accurately identified, the sooner you can modify your activity and work on modifiable risk factors to protect the bone and let it heal. This may mean a time period of non-weightbearing or no high-impact physical activity. This will depend on the injury site and whether it is a low or high risk non-union site. However, this doesn’t mean complete rest! Find a physical therapist that will prescribe appropriate exercises to stay as strong and fit as you can to avoid deconditioning.
  3. Graded Exposure – For more common low-risk bone stress injury and bone stress fracture sites like the posteriormedial tibial shaft, once you no longer have pain at rest or with daily activities you can start to gradually re-introduce physical activity and bone loading. This is in-conjuction with continuing to address modifiable risk factors and truly listening to your body while keeping track of your physical activity. One of our favorite phrases is you cannot manage what you don’t measure, keeping track of your steps, time on your feet, your workouts, and your runs early on can help you gradually increase load on the bone without doing too much too soon. Without measuring important variables, it is hard to safely progress loading and more importantly reflect back on what you did that may have caused a setback in your rehab and recovery.
  4. Seek Professional Help – If you’re dealing with what you believe to be a bone stress injury or bone stress fracture and it hasn’t improved in months, seek professional help. As stated earlier – these types of injuries, especially in high-risk fracture non-union locations, should not be taken lightly in efforts to avoid delayed recovery and/or surgical intervention.

Axial Loading Exercises

When appropriate/tolerated well with no pain during/after activity and minimal to no soreness after 24-48 hours, progressive axial loading exercises need to be performed. These types of exercises are necessary to optimally load the bone so that it can tolerate repeitive, submaximal forces that occur with high-impact activities like running. Below are a few examples of different exercises we like to incorporate within a cross-training program for runners.

Marching

Simple movement acquistion that mimics running is essential to practice and master before running. Marching can help improve running form and economy!

Single Leg Squats

Running is a single leg sport, building adequate unilateral leg strength is a pre-requisite to running!

Loaded Carries

Did you know running can produce forces up to 3-6X your body weight on your joints? Loaded carries are the perfect exercise to bridge the gap from low-impact to high-impact exercises to prepare your body for the large forcces imposed with running.

Pogos

Ultimately you have expose the involved bone and body area to impact. Pogos are a really nice way to introduce impact along with being easy to measure. You can keep track of total contacts with the ground, or keep track of how many rounds you did and for how long. For instance, you could start with 3 rounds of 30s and count how many times total did you contact the ground. The goal would be to increase volume to a few sets performed 2-3x/day as bone remodeling does better with small bouts of loading dispersed throughout the day versus a lot of volume done all at once. Allow for adequate recovery and bone remodeling to take place by taking off days as needed.

Easy To Follow Return To Running Protocol

When it comes time to run, the University of Delaware Return To Running Protocol is one we highly recommend. Two simple modifications with running that can also help with avoiding a BSI from occuring again are…

  1. Running ‘soft’ – think about making less noise with each step
  2. Increase step rate – increased step rate is associated with lower Ground Reaction Forces (GRF), which is basically the forces imposed on the body with running everytime you make contact with the ground (3)

Be sure to follow the return to running rules as well as the soreness rules to get back to running pain-free! You can also find another graduated running program to return a runner to 30 minutes of pain-free running by click HERE and looking at table 3.

Running On Resistance eBook

If you’re looking for the ulimate guide for runners, look no further than Running On Resistance by our close friend Chris Johnson. Click HERE to learn more

Supplemental BFR protocol

Blood Flow Restriction Training (BFRT) is becoming a popular rehab tool for bone stress injuries and bone stress fractures as there is evidence to support it can improve bone specific metabolism (4). This is an especially favorable rehab tool as it allows individuals to perform resistance training at low loads (20-30% 1RM) or non-impact/low-impact aerobic exercise and still achieve significant muscle size gains, strength gains, and even cardiovascular gains. In previous times, typically someone with a bone stress injury or bone stress fracture would become deconditioned due to inactivity/rest prescribed by their doctor. Now we can mitigate the amount of muscle atrophy and deconditioning using BFRT within this golden window of opportunity.

Bone and cartilage tissue is similar in ways to muscle, if you don’t use it you lose it! Unfortunately, being non-weightbearing and on physical rest does not stimulate bone optimally. As much as we need to protect the bone to let it heal, if we can find a way to stimulate the bone safely such as using a technique like BFR, we can help speed up recovery times. This can set people up for success when it comes time for graded exposure to high impact physical activities such as running.

Below you will find a BFR protocol we have designed for rehab from bone stress injuries and bone stress fractures. This is a rough outline along with exercise ideas and progressions that we have used in the clinic. It is important you consult with a healthcare professional and get clearance from your physician prior to participating in this protocol.

*For healthcare professionals – it is ok to extend and/or delay phases based on the injury site and risk profile, time period of immobilization and/or non-weightbearing, and response/tolerance to exercise progressions. This should be looked at as a flexible guide to help you manage runners with BSI or bone stress fractures, not hard rules*

Phase 1 – (Weeks 0-2) OR once the individual is cleared/appropriate for BFR. The typical scenario will be immediately after injury AND the individual is not mobile/non-weight bearing and cannot tolerate isolated/open-kinetic-chain resistance training with light loads (BW-40% 1RM)

Cell Swelling Protocol – 80% LOP determined using a doppler, 5 minutes on, 3 minutes off, up to 5 rounds and can be performed 1-2x/day for 5-6 days a week

  • Session 1 – Two to three rounds of cell swelling with focused isometrics as tolerated, otherwise passive or with e-stim (3s contract, 1s relax) I.E., if femoral shaft stress fx – perform quad sets OR in foot/ankle complex – perform isometric plantarflexion by pulling the foot into dorsiflexion with a resistance band but not letting the foot move.
  • Session 2 – Three to four rounds of cell swelling with same parameters above
  • Session 3 and on until performing isolated/CKC/compound exercises – perform 5 rounds of cell swelling with the same parameters above

2-3x/week Biking Protocol – An option if non-weightbearing period is extended (3 or more weeks) and biking is OK. This would replace the cell swelling protocol.

  • Bilateral BFR is better than unilateral for more cardiovascular adaptations, however unilateral on the affected side is appropriate
  • Session 1 – Perform 1-2 rounds of biking for 5 minutes at 40% Heart Rate Reserve (HRR), if the individual is deconditioned or having difficulty you can decrease to 30-35% HRR. The occlusion is continuous while biking with at least 1 minute of deflate/free flow between rounds.
  • Session 2 – Perform 1 round of biking for 10 minutes or as tolerated at same HRR as session 1, the occlusion is continuous while biking
  • Session 3-4 – Work towards 15 minutes total of biking, can be continuous or with multiple rounds (I.E., 3 rounds of 5 minutes), at least 1 minute of deflate/free flow between rounds. Increase HRR by 5% from Session 2.
  • Session 5 and on – Increase biking volume and intensity working towards 20 minutes of continuous biking at 50% HRR with ideally 80% LOP occlusion. Increase HRR by 5% each week until you reach 50%.

 

Phase 2 – (Weeks 2-6) OR once the individual is weight-bearing and can tolerate isolated/open-kinetic-chain resistance training with light loads (BW-40% 1RM)

  • 2x/week – BFR with treadmill walking at 60-80% LOP
    • Bilateral BFR is better than unilateral for more cardiovascular adaptations, however unilateral on the affected side is appropriate
    • To hit target training HR, increase incline if needed after reaching 3.5-3.7 MPH, limit individual to brisk walking only vs. jogging/running.
    • Session 1 – Perform 1-2 rounds of walking for 5 minutes at 40% Heart Rate Reserve (HRR), if the individual is deconditioned or having difficulty you can decrease to 30-35% HRR. The occlusion is continuous while walking with at least 1 minute of deflate/free flow between rounds.
    • Session 2 – Perform 1 round of walking for 10 minutes or as tolerated at same HRR as session 1, the occlusion is continuous while walking
    • Session 3-4 – Work towards 15 minutes total of walking, can be continuous or with multiple rounds (I.E., 3 rounds of 5 minutes), at least 1 minute of deflate/free flow between rounds. Increase HRR by 5% from Session 2.
    • Session 5 and on – Increase walking volume and intensity working towards 20 minutes of continuous walking at 50% HRR with ideally 80% LOP occlusion. Increase HRR by 5% each week until you reach 50%.
  • 2x/week on separate days from BFR treadmill program – BFR with progressive resistance training at 60-80% LOP
    • Bilateral BFR if desired for more systemic effects and training the other side, however unilateral on the affected side is appropriateย 
      • Exercise parameters are 30/15/15/15 reps with 30s breaks between each block of reps, continuous occlusion for the entire 75 reps. 1 minute of rest and deflate/free-flow between each exercise.
      • Sample progressive program below – general rules are starting with isolated/non-weight bearing exercises and progressing towards closed-kinetic-chain and upright/weight-bearing exercises
    • Session 1
      • Double Leg Bridge with band above knees
      • Clams with band above knees
      • LAQs with band around ankles or ankle weight
      • Long sitting ankle PF with band
    • Session 2
      • Double Leg Bridge with band above knees
      • side-lying hip abduction (with a band above knees if tolerated)
      • LAQs with band around ankles or ankle weight
      • Loaded Seated heel raises
    • Session 3
      • Bodyweight squats with band above knees
      • Standing heel raises
      • Staggered stance Bridge with band above knees
      • LAQs with band around ankles or ankle weight
      • Loaded Seated heel raises
    • Session 4
      • Staggered bodyweight squats with band above knees
      • Anterior step-up
      • Loaded Standing heel raises
      • Staggered stance Bridge with band above knees
      • Leg extensions @ 20% 1RM
    • Session 5
      • Loaded anterior step-up
      • Single Leg heel raises
      • Loaded goblet squats with band above knees
      • Single-Leg Bridge with band above knees
      • Leg extensions @ 25-30% 1RM
    • Session 6
      • Posterior step-down
      • Loaded Single leg heel raises
      • Split Squat
      • Loaded Farmer Carry
      • RDL bodyweight
    • Session 7
      • TRX single leg squat
      • Split Squat
      • Loaded Single leg heel raises
      • Loaded Farmer Carry on toes
      • RDL with weight
    • Session 8 and on
      • Strength training with the progressive overload principle
      • Continue to integrate more planes of motion and unilateral work
      • Continue to progress axial loading while targeting the specific affected tissue
      • Move away from BFR and towards high-load resistance training (>65% 1RM) once tolerated
      • Introduce progressive plyometrics when appropriate in preparation for graded exposure return to running
        • Landing drills
        • Pogos
        • Jogging in place
        • Skipping

 

Phase 3 – (Weeks 6+) OR once the individual has started a graded exposure return-to-running protocol

  • 1x/week – BFR with treadmill walking at 60-80% LOP
    • Working towards 20 minutes of continuous walking at 50% HRR with ideally 80% LOP occlusion
  • 1x/week on separate days from BFR treadmill program – BFR with progressive resistance training at 60-80% LOP
    • Working towards 5 closed-chain compound axial loading exercises while targeting the specific affected tissue
  • When high-intensity resistance training (HIRT) is tolerated (>65% 1RM) symptom-free, replace BFR with HIRT for at least 2 sessions/week while running on opposite days.

 

References

  1. Tenforde AS, Kraus E, Fredericson M. Bone stress injuries in runners. Phys Med Rehabil Clin N Am. 2016;27(1):139โ€“49.
  2. Pegrum J, Crisp T, Padhiar N. Diagnosis and management of bone stress injuries of the lower limb in athletes. BMJ 2012;344:e2511.
  3. ย Warden SJ, Davis IS, Fredericson M. Management and prevention of bone stress injuries in long-distance runners. J Orthop Sports Phys Ther 2014;44:749โ€“65.
  4. S. T. Bittar , P. S. Pfeiffer, H. H. Santos and M. S. Cirilo-Sousa. Effects of blood flow restriction exercises on bone metabolism: a systematic review. Clin Physiol Funct Imaging (2018). doi: 10.1111/cpf.12512

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