New Evidence on Running Injuries...Thinking beyond simple "overuse" (Physician's Update Nov 2020)

[Peak PT Administrator 0]

EVIDENCE BASED PRACTICE UPDATE

November 2020

 

    New Evidence on Running Injuries...

    Thinking beyond simple “overuse”

 

WHAT WOULD YOU DO?

A  27 yr old recreational runner complaining of unilateral plantar fascia pain developing with running 2 wks ago after increasing mileage  from 20- - >30 mi/wk   over the prior  3 weeks is in for evaluation.  They have run for 6 years with only short  bouts of minor musculoskeletal issues related to running, never requiring formal care,  never needing more than  one week rest.  This  time   one week rest  did not  allow  a painfree return to running.  Their shoes  demonstrate  substantial lateral  aspect  of heel wear patterns.  You notice an  asymmetric medial collapse  on  that  side during  a brief hallway jog  assessment.  PMH includes an ankle  sprain one year ago that is no longer symptomatic and patient reports  100% function restored.

·       Do you recommend complete rest for 2-3 weeks from running?

·       Do  you order  Physical Therapy or NSAID’s first or both?

·       If NSAID’s  -  do  you have any reservations regarding affects on stages of tissue healing?

·       What is your hypothesis for unilateral symptom  development?

·       What  immediate recommendation can you give to alter  potential  abnormal  forces  while potentially allowing some running     still?

·       Do you have a generic “plantar fasciitis protocol”  that   addresses this patient’s contributing factors?

·       Do you expect the Physical Therapist to implement the generic protocol or to evaluate the patient for unique biomechanical influences and address  accordingly?

 

SUMMARY

Physicians regularly see runners who are experiencing pain and looking for solutions.  The current pandemic may compel even more fitness enthusiasts to take  up running as  gyms are  closed or limited.  Beyond making a diagnosis and recommending proper treatment/therapy physicians are in position to immediately impact symptoms for many runners with in-office  education.  Last month  (Click HERE to read) we brought you a running article that showed a common flaw in running (abnormal hip adduction via pelvic drop) that was a significant cause of injury in many runners.   This month’s review focuses on impact-related ground reaction forces (GRF) in running.  Johnson  et al showed that  various markers related to GRF  were  greater  in  injured runners vs healthy controls and  also uniquely  for those  subgroups  with  patellofemoral pain, plantar fasciitis, and achilles  tendinopathy but not for tibial stress injury  or ITBS.  While the findings demonstrate an association and not necessarily causal relationships, in combination with  other  existing literature there is  good  basis for counseling  and training runners  in  methods to reduce  GRF.  Physicians can simply do so with  several  different recommendations when they believe impact related forces are playing some role  in a  runner’s  symptoms. 

 

CURRENT EVIDENCE

Johnson, Adam, Tenforde, Davis.  Impact-Related Ground Reaction Forces are More Strongly Associated With Some Running Injuries Than Others.  AJSM, 48:12, 2020 pp. 3072-3080

Background:    It has been reported that 33-50% of recreational runners sustain injuries, with the causes of which are multifactorial.   This includes things like running mechanics, shoe choice, ground stiffness, muscle strength/endurance, flexibility, and daily or weekly mileage.  Common injury diagnoses are primarily divided into the achilles tendonitis/tendinopathy, patellofemoral pain, plantar fasciitis, tibial bone stress related and iliotibial band syndrome.  

Purpose:   This controlled  lab study retrospectively compared vertical load rates and stiffness between healthy and injured runners and also within injury groups.

Methods:   Male and female runners age 25 to 52 y.o. with >2/10 pain on a VAS during running who used a rearfoot striking running pattern and utilized conventional running shoes (ie. not minimalist shoes) met the inclusion criteria.  One hundered twenty-five injured  runners (divided among the five diagnoses: Patellofemoral pain, Iliotibial  band syndrome, Tibial bone stress injury, Achilles tendinopathy, and Plantar fasciitis) were  compared to 65 matched healthy controls.  All participants were analyzed at one treadmill session with 3D video analysis using a self-selected speed.  Ground Reaction Force  (GRF) variables were measured and compared between groups and also for individual diagnoses.   GRF measures  included  Vertical Stiffness (change in the body’s center of mass [COM] relative to a change in the vertical GRF),  VILR or Vertical Instantaneous Load Rate  (peak rate of change in vertical GRF between two successive points), VALR  or Vertical Avg Load Rate (avg rate of change in vertical GRF across 20% to 80% of the region of interest),and VSIL or Vertical Stiffness at Initial Loading (peak vertical force divided by the vertical change in COM over 20-80% region of interest).  (See Figure)

 

 

Results:    Injured runners had a significantly higher VALR compared to healthy controls.  VALR and VILR were higher in the patellofemoral pain and the plantar fasciitis groups compared with healthy controls.  Significantly higher VSIL were found with patellofemoral and achilles tendinopathy groups in comparison to the healthy control groups.  All injured groups showed significantly higher force impact  (16-20%) in all 3 areas but only the above reached statistical significance.

Authors’ Conclusion:   Impact  variables  for the injured  group  were  higher than  healthy controls but are driven  by specific injury diagnoses.   This highlights the need  to take an injury specific approach  to biomechanical risk factors  with  running injury.

 

PEAK PERFORMANCE PERSPECTIVE

Karen Napierala, MS, AT,  PT, CAFS

 

With the gyms vacillating between closed and open in the past 6 months many people are opting to keep it simple…. to run.  This potentially means more people who have not trained to run now will be running to train or stay fit.  This will likely lead to more physician office visits due to a spike in injuries.   It bears repeating – 33-50%  of  recreational runners will  develop injury.  Physicians can easily also go beyond the necessary diagnostic role  with early treatment via patient education/counselling (see below).

These results certainly suggest that we need to address impact loading for injured runners, especially at least those who are  rearfoot strikers and have patellofemoral  pain, plantar fasciitis, or achilles  tendinopathy.  Johnson  et al’s findings also support Van Der Work et al’s findings of a positive association between vertical impact rates and general running-related injuries.  These longer term studies have also shown the increased loading rate directly related to the progression of injury and further cartilage damage.  

From a treatment perspective it is encouraging to note that Chan et al did report that training runners to reduce vertical loading rates lowered running injuries by 62% over one year.  

Physicians  are in a  unique position even during their  first encounter with  runners who rearfoot strike to begin education/counselling.  Runners should  know that studies indicate >40 miles/wk increase injury risk  within the next year.   And, we must remember - runners  WILL often keep running  regardless of having pain.  Rather than ordering a full stoppage initially it’s possible to help them find the threshold  where they remain pain free.  Here are two simple, practical  methods to reduce  the volume and then the severity of GRF based contributing factors:

1.     Determine total weekly mileage.  The first  option, of course, is simply to have them cut their daily  mileage (2/3, ½...etc)  and reduce frequency by 1 day/wk to begin with.  Many runners we see admit to non-compliance  when an “all-or-nothing” complete refrain from all running is the first recommendation a physician or PT gives. 

2.     Increase cadence by 10%.  Efficient runners often have a cadence (step count) of 85-95 steps/minute  (ie.  170-190 stride rate).  Advise your runner to count their steps  (every time R  foot lands)  in one minute when they are fresh and then again when they are fatigued  or at the end of a run (ie., a runner at 77 step count would have to add 8 steps to their cadence and now reset the metronome at 85).  There are free metronome apps they can download to their phone, providing an excellent and consistent audible cue for them.   

Rearfoot strikers particularly have been known for their slight over striding at heel strike which increases GRF.  This can happen for two reasons.  First, is when the runner reaches forward with their heel  to contact the ground. (Could be many reasons including tight ankles, hips or weakness in the calf…ETC) The heel contacts hard, leading to “braking” type  forces and the runner “pulls” themselves thru instead of leaning forward more, landing their heel closer to the COG, and “pushing off” to propel themselves forward.  The second is when runners “sit their hips back”, causing an anterior pelvic tilt (potentially related  to tight hip flexors, weak gluteals...etc).  While the heel strike itself distally doesn’t appear visibly as anterior as the “overstrider”,  the proximal pelvic segment/COG are relatively more posterior.  The outcome is the same – increased GRF at heel strike.  This, of course, then has  ramifications up the kinetic chain  as well.

For example,  high vertical load rates can result in increasing sagittal plane forces at the patellofemoral joint leading to rising patellofemoral joint (PFJ) compression forces.

Increased vertical loading causes greater rates of vertical arch deformation which in turn stresses the plantar fascia, first in the sagittal plane but as the arch collapses it does so concurrently in the traverse/frontal planes also.  This contributes to overloading other  tissues related to local shock absorption distally as well.   In this study Johnson et al found  plantar fasciitis group values of 52.4BW /s or higher for VALR  associated with 11x  increase in injury risk.     

This study, oddly, did not find increased GRF forces in the tibial bone stress runners subgroup.  However, these runners had taken 1-2 months rest off as part  of  their treatment, prior to the study, and  were allowed to run with a max of 2/10 pain, which possibly meant they were  using altered/compensating mechanics.    

Mean vertical loading rates were not significantly higher in the ITB or achilles tendinopathy groups.  These injuries have been linked with frontal and transverse plane weakness or excessive motion. Traditional PT often overlooks or  misses these  issues, like frontal plane  stiffness in calcaneal eversion as a cause of distal foot overpronation (MTJ). 

 

Vertical stiffness during impact loading measures downward excursion of the COM per unit of force during the early stance. These “stiffer” joints are less able to dissipate external forces resulting in increased rate of injury.  Higher knee joint stiffness and injury have been associated previously in other studies. 

Conversely,  a decrease of vertical stiffness (ie. excessive collapse)  is also a potential risk factor.  Research has yet not pinpointed the exact amounts of stiffness necessary to prevent injury and properly dissipate forces.  There is a likely safe range that is dependent on an individual’s biomechanics, strength and flexibility, etc. 

This study was retrospective.  Therefore we’re  uncertain whether it  was  capturing  biomechanical factors that were causative of the injury.  Studies do show that 86% of all runners will run through pain.  This fact compels us as health care providers  to carefully address  running injury since runners who  do, in  fact, continue  to  train may be risking more severe  or additional injury -  leading to  even more eventual disability, time off running, medical intervention and expenses downstream.   This study differed in in that the runners here were rested for at least a month before being tested.  Many prior studies looked at runners who were running their normal mileage while still in pain.

This study had several limitations which the authors  astutely noted.  First, regarding external validity, because rearfoot strikers only were allowed to participate, the results cannot be extrapolated to fore- or midfoot strikers.  It is important we caution against  overgeneralizing these findings to runners in general especially as we more and more runners hearing about and attempting  to utilize mid and forefoot  strike patterns.  

The authors calculated  risk thresholds (ie.  VALR > 57.4BW  in the patellofemoral pain group was linked to knee pain).  These  GRF injury risk thresholds (Table 4 in original article) are not intended to be definitive since  this was not an experimental design study  able to demonstrate causality.  

While it is accepted that increased force is  associated with increased likelihood of injury down the road, it remains unclear what  that time duration prior to symptom  onset  might be or  the  threshold for tissue  overload  that triggers  inflammation and symptoms,  especially regarding  the level that alters function.   

It is impossible to establish whether the observed differences in this study are a cause or result of the recent injury.  At what point do runners in pain modify their running mechanics, and to what degree, in order to decrease symptoms and continue to run?  Johnson et al looked at runners after they were injured.  Future prospective studies examining GRF patterns of asymptomatic  runners and then following   them over time to  determine the relationship  between  many of these  impact  related variables and  subsequent injury  would  be even  more  helpful to physicians  and therapists  clinically. 

Injured  runners require skilled  physical therapy  capable  of analyzing gait patterns that may contribute to  increased GRF  variables like Johnson  et found in  this study.  Traditional  or generic/protocol based therapy approaches often fail  to identify  functional biomechanical  factors  contributing  to the “why” a  runner is  performing the skill or gross motor activity of running  in  the way they do.   We  must assume  runners, like most  athletes, are likely either utilizing the  mechanics  that  inherently/naturally  feel most efficient within  their own body (based on  the capabilities and the limitations they have)  and/or  are based on their  interpretation of what they’ve learned or observed  as  “proper technique”  that they are attempting to  emulate. 

Running is a complex and integrated biomechanical skill. Not every injury has the same cause.  There are internal biomechanical issues, training issues, and impact force issues among  others.  What caused the impact force to be intolerable on one side of the body when each foot took the same number of steps?  Determining why one side had an increased force across the injured tissue is a key puzzle to be solved.

It is imperative that  therapy  be  capable of analyzing functional mechanics issues  that   my underlie  abnormal running   form and/or  contribute to  inefficiencies that lead to  tissue overload.  Thorough  3D  testing and  exercise progressions that  resonate with  the  proprioceptive/neuromuscular system  are  key.  For example, the hip abductors being trained to forcefully abduct the thigh is  not “authentic” hip abductor   force  use.  In  running  the abductors  stabilize  the pelvis and decelerate  mild  normal pelvic  drop into hip adduction before concentrically contributing to re-leveling of the pelvis for  push off.  Concepts such as  this are often missed  with common clamshell or circle  tubing abduction walk  drills that do, in fact, “work”  those muscles but are  not authentic in their  true preparation for  running. 

Certainly GRF in runners is controllable to a significant degree by altering the forces at impact, in the case of runners, particularly with rearfoot strikers via increasing running cadence or steps/minute.  Often in the clinic the injured runner is down around 75-80 steps per minute.  They may think running slower is better for them, or easier...not realizing that when many runners lower their cadence they end up overstriding and thus increasing  GRF.  Recommending an  increase in stride rate will actually move COM forward and decrease their impact forces through the heel, which, based on this study, may be helpful  especially for runners with PFPS,  plantar  fasciitis,  and achilles tendinopathy. 

 

PEAK PERFORMANCE PATIENT:

Marley  said:  “ I didn’t know I would feel so much faster and more efficient when I run at the higher step count. This is the strongest I have ever felt!“

History:     Marley was a collegiate runner training at 35-40 miles/week.  She developed L hip symptoms that were diagnosed at school as hip bursitis.   Rest was ordered but every time she tried to resume running the pain returned.  We met Marley at a runners camp where she was assisting in coaching high school runners. Being around other runners only fueled her desire to run.

Objective:     Standing STJn showed leg  length discrepancy.  NWB and WB hip Abductor length testing showed  tightness.  FWB recovery from Hip Adduction was poorer.  Asymm foot overpronation noted with esp SLB  dynamic  testing.  Subsequent TM run test once  painfree showed an 18⁰ inclination angle  at heel  contact and  a  cadence of  78.steps/min on  R foot.  (See  Fig A)

          Fig A                             Fig B

           

 

 

 

 

 

 

 

 

 

 

 

Discharge Re-Evaluation:    Marley’s  running was again analyzed in 2D (Figure and her angle of inclination at foot contact was now 12 degrees. She had a cadence of 88-90 steps/min R LE.  She was still a heel striker, but the contact point on her heel was slightly anterior to the original contact point.  Her body lean was inclined forward, and she felt much stronger and able to push off easier.  She self selected a comfortable speed of 6.5 mph on the second analysis. She has been running now for 6 weeks and has zero pain. 

 

Treatment:

Initial:    Shoe lift to address LLD.  Functional dynamic stretching for  her  ITB/TFL  along  with  WB based strengthening of  hip Abd’s and ER’s as well.  Dynamic balance exercises promoting pronation  deceleration and the ability to resupinate were initiated and advanced.  Superfeet  OTC inserts  were obtained  and self-adhesive posting was added to semi-customize biomechanical demands.  

Subsequent – once symptoms gone:      Cadence was increased for Marley to 84 and maintain that for 5 minutes in a 30/30 walk/run using a metronome app on her phone to ensure proper pace.  She was taken up to 88-90 steps/min with the use of a metronome to ensure keeping the new cadence. Ran 3-4/week while also continuing her strengthening and functional stretching program.  She did this for four weeks and gradually increased her run 5 seconds while decreasing her walking 5 seconds until she was running 5 minutes.  When was then able to gradually maintain that new cadence she would increase the running by one min every three days.  Once she hit ten minutes successfully, she used the metronome sporadically only and continued her gradual increase in time running.  

                 

You can trust the Physical Therapists at PEAK PERFORMANCE to do a thorough evaluation, to search for related but underlying contributing factors to kinetic chain dysfunction, and to design exercise progressions that both respect tissue healing and creatively use biomechanics principles to prevent symptoms and optimize carryover to your patients' functional goals. Call us at 218-0240 to discuss your patient's specific needs.   Karen Napierala, PT, AT, MS, CAFS

Peak Performance is just minutes away from your patients in Penfield, Fairport, Pittsford, Brighton, Rochester and, of course, East Rochester.   We promise Individualized, hands-on and biomechanically appropriate Physical Therapy for your patients.  No "one-size-fits-all" approaches. We WILL go the extra mile and "dig deeper" to discover underlying causes for injury risk and delayed recovery using the most advanced Evidence Based methods available and, we’re able to make unique adjustments to exercise prescriptions to speed the return to function and to minimize or prevent symptoms from interfering.    No surprises. No hassles. Confident your patient is in the right place.   COME VISIT US AT 161 E Commercial St Just 1 mile off 490 exit (585) 218-0240 www.PeakPTRochester.com