Hump Day Hustling – Weekly Research Summary – January 31, 2024

Zone 2 cardio made simple, running rehab X 2, and science helping us navigate exercise intolerance post-COVID. It’s another packed week in Hump Day Hustling! Enjoy, and if you want to dive deeper with ICE content make sure to check out our Upcoming Course Dates and Locations.

Bias Check

Gait asymmetry NOT always predictive of injury?

We want it to be simple, namely that what we see on the video will directly correlate to what our runners will experience on the road and trail. But alas simplicity shall remain elusive!

This open access 2024 article by Malisoux et al. reports on asymmetries during running & relation to injury risk. The authors looked at spatiotemporal variables (step length, contact time, vertical COM displacement, impact peak, peak vertical ground reaction force (GRF), loading rate, etc) of over 800 recreational runners and found that gait asymmetry was prospectively not associated with higher injury risk. However, asymmetry in flight time and peak braking force was associated with lower injury risk. Other interesting outcomes of this study: GRF and loading rate variables demonstrated up to 10% asymmetry while asymmetry for temporal variables like contact time was below 2%. It’s also important to note that this study did not look at kinematic variables (ROM, step width, trendelenburg, etc.)

Clinical take away: We cannot assume that runners with certain gait asymmetries are at an increased risk for running related injuries and currently the research does not support intervening on these asymmetries to reduce running related injury risk.

Injured Runners Take 2

Patellofemoral pain: What’s different?

Admittedly, the first article took some wind out of our gait analysis sails BUT there is still plenty out there to be encouraged by, like this study by de Souza Junior et al.. The authors used a statistical method called Classification & Regression Tree (CART) to classify runners with patellofemoral pain into subgroups. Participants were 38 runners with PFP and 38 healthy controls.

Key findings: Three main biomechanical variations within groups of runners with PFP: 1. Decreased braking GRF impulse (the area under the GRF curve), most likely related to quad avoidance. 2. Increased braking GRF impulse + greater contact time, related to reduced step rate and overstriding. 3. Increased average loading rate and older age, with the loading rate related to increased PF joint demand.

From these results we can confirm that PFP remains a multifactorial problem and it’s unlikely that a single biomechanical fault contributes to or perpetuates PFP. The results are more likely to reflect compensatory patterns vs precursory as this study is retrospective. Finally, regardless of contributing factors, rehab is necessary to increase PF joint load capacity &/or alter mechanics to decrease joint demand.

Zone 2

How and why

We often bring up Zone 2 cardio in the ICE spine management courses. When people ask for clarification it’s been tough to provide a resource because a lot of the respected individuals providing their takes often do so in a long winded and confusing manner. This clip is a welcome outlier being short and providing specific examples of how to mesh Zone 2 throughout life. An added bonus is the emphasis on doing this outdoors!

The other intriguing part of the clip is this can be thought of less like exercise, and more like a part of what improves fitness/social activities/productivity ETC. We dig that there is no upper limit here and that people can chill out if they are worried about their zone 2 stealing from other forms of exercise, it’s just movement!

Just make sure you can pass the talk test, but it’s more straining than normal conversation, and get moving!

Covid and Exercise

When more isn’t better

You’re all seeing post-COVID patients in the clinic, the numbers simply don’t allow for an alternative reality. While most are doing well, a small subset has persistently struggled especially with exercise, and science is beginning to answer the question why.

Recent study biopsied muscles from long Covid patients both before and after exercise and found significant cellular changes in both, explaining structurally why many long Covid patients can’t tolerate activity and exhibit severe post exertional malaise. This article is from NPR, is very readable for those wanting to learn more!

Hump Day Hustling - Weekly Research Summary - January 31, 2024 - Partner Corner

PTonICE Rewind

Did you miss any of our ICE Physio podcasts last week? Well here you go!

Monday: “When back pain isn’t in the back” (Jess Gingerich)
Tuesday: “A Cert-ORTHO approach to CTS” (Lindsey Hughey)
Wednesday: “Workout ideas for the hospitalized patient” (Julie Brauer)
Thursday: “Friction coefficients and your business” (Jeff Moore)
Friday: “Return to run following joint replacement” (Jason Lunden)​

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