Recently, my colleague and friend Tom Goom shared an excellent graphic on the pros and cons of running gait re-education.
Source: Tom Goom
This spurred me to write this short piece on what we currently know and what is missing with regards to running gait re-education in my specialist field, patellofemoral pain (PFP).
I am currently undertaking a PhD at Queen Mary, University of London entitled:
The Effects & Mechanisms of Running Gait Re-Education in the Management of Patellofemoral Pain
Two other excellent resources for all things running gait re-education are Dr. Richard Willy from East Carolina University across the pond, and of course Dr. Andy Franklyn-Miller at SSC, Santry in Dublin.
Something that we are passionate about at QMUL is investigating both the effects and mechanisms of an intervention, that is, what works and for what reasons for our non-clinical readers. A better understanding of mechanisms is imperative for identifying the holy grail of ‘sub-groups’ in medicine to best determine who may respond best to a given intervention.
There have been three trials of running gait re-education in PFP currently, with a total sample size of 30 participants, unfortunately all female:
- Noehren et al (2012): http://www.ncbi.nlm.nih.gov/pubmed/20584755
- Willy et al (2012): http://www.ncbi.nlm.nih.gov/pubmed/22917625
- Willson et al (2014): http://www.ncbi.nlm.nih.gov/pubmed/24439063
There have been two other quality case series described (n=5):
- Cheung & Davis (2011): http://www.ncbi.nlm.nih.gov/pubmed/22031595
- Willy & Davis (2013): http://www.ncbi.nlm.nih.gov/pubmed/24175611
There is also a plethora of additional observational data in normative subjects, which we will not discuss here but has been covered in previous articles on this website:
- Movement Dysfunctions Behind Patellofemoral Pain in Runners
- ITB or Not ITB… That is The Question
- You Don’t Have to Take Your Shoes Off, to Have a Good Time
This is what we know at present:
- In a short-term follow up (three months), running gait re-education has been shown to significantly improve pain and function in subjects with PFP, using a variety of outcome measures. We have seen significant changes in both the ‘Lower Extremity Functional Scale’ and the ‘Kujala Scale’, alongside pain when measured using a typical Visual Analogue Scale. Whilst the above studies are small, both the Noehren & Willy papers are statistically powered a priori for their given outcome measure at a short-term follow up.
- The primary mechanism is thought to be kinematic; we have seen significant reductions in hip adduction and contralateral pelvic drop, as well as trends towards significance for hip internal rotation. This is especially important when mapped against the known prospective risk factors for PFP.
- We can reduce patellofemoral joint stress: the excellent controlled laboratory study by John Willson (first presented at the International PFP Research Retreat in Vancouver last year) identified a significant change in both peak and net patellofemoral joint stress when manipulating running cadence. They did identify a significantly greater change in normal subjects versus symptomatic subjects however, which suggests reducing joint stress may have more preventative effects.
- A variety of feedback mechanisms can extract change; visual (live hip adduction tracking & mirror), audio (cadence metronomes and foot strike facilitation) and verbal cueing have all lead to similar alterations in kinematics. Of these, audio metronomes and visual mirror feedback are the most clinically applicable, an important variable to consider when designing a study.
This is what we currently do not know:
- What happens beyond a short-term follow up; nothing has been studied outside of a three-month follow-up. We are targeting a twelve month follow up in our clinical trial, to be classed as long-term as per the Cochrane guidelines.
- How do male subjects with PFP respond to running gait re-education; whilst PFP is three times more common in females than males, which drives a female bias in samples, it is imperative that we seek more male subjects in future studies in order to improve the clinical applicability of results.
- How does running gait re-education perform in comparison to other clinical modalities; at present no-one has investigated running gait re-education against the current gold standard treatment for PFP, multi-modal physiotherapy. This is why we are using a control group of primarily hip ‘strengthening’ exercises in our clinical trial, which also needs efficacy confirmed/negated at a long-term follow up.
To give you an idea of what we are facing, we need to investigate 130 runners with PFP (65 per group) over twelve months to detect the ‘minimal clinically important change’ (MCIC) in our primary outcome measure, being the Kujala Scale. We will therefore need to recruit a total of 150 runners (75 per group) to allow for accepted rates of attrition. I hope this gives you an idea of how difficult some aspects of research design and completion is, so to my fellow clinicians, please go lighter on underpowered studies in the future, as long as they accept this in their discussion it is fine, research isn’t easy!
But for now, please continue to use running gait re-education with your patients with PFP if you have the confidence (perhaps consider this CPD course). It can successfully alter pain and function in the short-term in runners with PFP, which is very clinically relevant. My personal stance is that cadence manipulation (+ 5-10%) with an audio metronome incites the greatest level of kinematic change for the mean average patient, but remember this will most likely develop a runner for function and not necessarily for performance. This is where James and I work together, the physiotherapist and the coach, for the best outcome in our athletes.
For now, many thanks for reading and as always, comments are welcomed by all but please forgive me if my reply is somewhat tardy.