ATC 304: Do Runners Really Work 30% Harder on Curved Non-Motorized Treadmills vs. Traditional Flat Treadmills? Plus: Running After Meniscus Surgery, How To Push Heart Rate While Cycling, and More

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Intro

• MAF meetup was a success!
• Floris Gierman “won” with the best MAF pace. He’s a passionate student of MAF and you can check him out here: https://extramilest.com and https://extramilest.com/podcast/

Mike C. asks:

Curved treadmills- are they harder, same, worse and should we tailor workouts?

Thank you for the fantastic podcast and recommendations.  Due to various reasons many of us will be running on treadmills this upcoming season.  While nothing is a perfect match for outdoor running as outdoor running itself, Curved Manual Treadmills are being promoted by many as closer and more realistic than flat, motorized treadmills. Additionally, there are claims that it can help promote better running form and better use of posterior muscles (https://www.mdpi.com/2075-4663/6/3/58/htm).  I was hoping to get your opinion.  There are some differences between the brands such as maximum curvature, curve radius and belt friction which at least one manufacturer says makes a difference.  I also know Dr. Mark Cucuzzella has a couple set up in his store and I trust his opinion.

CMTs appear to be significantly more difficult:

1) https://www.ncbi.nlm.nih.gov/pubmed/29789265

2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5694659/pdf/fphys-08-00914.pdf

3) https://www.ncbi.nlm.nih.gov/pubmed/30084302

4) Runners World had an article that cherry picked a study and suggests another that is being worked on saying running on a CMT is similar to running on a regular treadmill at 8% incline: https://www.runnersworld.com/training/a20950925/you-are-working-harder-on-a-curved-treadmill/

Some people I know say that to account for this difficulty, they adjust their workouts by 20% as suggested in the above linked RW article.  (I.e. they mark their distance as 20% greater than what the treadmill says and since their workout duration is constant their pace is increased by 20%.  To me, this seems like cheating but the couple of runners I spoke with says that this is almost a perfect match for their RPE and running outdoors.)

Here is a nice review article from simplifaster: https://simplifaster.com/articles/curved-treadmills-pros-cons/

This brings me to a couple of questions:

1) We have all heard of “live high, train low”.  Is training on a CMT the opposite and thus counterproductive?

2) If our goal is to run long distance, isn’t it counterproductive to work at higher metabolic cost?  Don’t we want to be as efficient as possible? Or am I not thinking about this correctly?

3) Do you think we should adjust our workouts similar to previously stated if running on a CMT?

4) If we are going to do Treadmill Running, what are your thoughts on CMT vs traditional flat, motorized treadmill running?

Just wanted to add a brief addendum:

I find that with my current motorized flat treadmill that it feels my deck gets a bit unstable and bouncy as I approach 12 mph (5:00 min/mile) on short intervals.  I did brief test runs on 3 different manufacturers of CMTs (and I do notice differences between them) and did not experience any of the unstableness and felt very comfortable at the higher speeds.  I also like the idea of quick acceleration/deceleration of the CMT and you self select the pace instead of running at treadmill defined pace.

What the Coaches say:

• Curved treadmills are great for hill training
  • “Schoenmakers also pointed to curved treadmills as being a useful tool to practice hill running for athletes living in flat territory, noting that the machines are a great workout for the posterior chain muscles: glutes, hamstrings, calves. (He and his coauthor, Kate Reed, are working on a study showing curved treadmills represent the equivalent of an 8 percent grade on motorized treadmills.)“(source)
• See this study: The physiological and perceptual demands of running on a curved non-motorised treadmill: Implications for self-paced training
  • “Runners really do work about 30 percent harder on the curved, non-motorized treadmills and to expect a 20 percent difference in pace.”
  • “No participant was able to complete the 4 min run at 80% Vmax on the cNMT. Running on the cNMT elicit a higher relative oxygen uptake (%VO2max) across all velocities compared to the MT and was accompanied by significantly higher heart rates  an altered cadence and ratings of perceived exertion. A less efficient running economy was evident when running on the cNMT.”
• Another insightful study: The Effect of a Curved Non-Motorized Treadmill on Running Gait Length, Imbalance and Stride Angle
  • “Approximately 75-80% of distance runners are rear foot or heal strikers. Most of the remainder are considered midfoot strikers [22].” (And about 79% runners report injury- coincidence?)
  • “The results show that running on a CNT resulted in significant changes in gait characteristics (step length, stride length, imbalance score and stride angle). These findings suggest that running on a CNT can significantly influence running gait.”
  • >Stride length and step length decreased, seen as advantageous (less heel striking, less impact)
    • “As the stride length decreases with greater exposure to the arced non-motorized treadmill, so does the step length. Research has indicated that a link exists between the stride length and impact characteristics, such that as the finding that stride length greatly increases impact [23,24,25]. A reduction in stride length, although it would appear smaller in trained runners, may be advantageous, as it has been shown to reduce impact peaks [26,27,28] and loading rates [28,29,30] experienced by runners. A shorter stride length means that the heel is located more underneath the center of mass (COM), which reduces the amount of hip and knee flexion required [31]. A more efficient running gait pattern leads to a reduction in stride length of 6–8% in inexperienced runners and those with a long history of running [26,27,28,29,30].”
  • >Decreased asymmetry/imbalances
    • “As step and stride length decreased, and speed stayed constant, the amount of time that either lower limb spent in support decreased accordingly, resulting in a decrease in imbalance. When examining the data, one can readily see a great decrease in the imbalance score from TMT-1 to TMT-2, as compared with that from TMT-1 to TMT-3.”
  • >Improved stride angle
    • “Results from this research show that 4-min bouts of running on an arced non-motorized treadmill influence stride angle in a statistically significant manner. The mean trend for stride angle as a result of running on an arced non-motorized treadmill is indicative of better running economy via a decrease in contact time.”
• The coaches agree that the curved treadmill offers a number of benefits (especially improved running economy). But it will drive you crazy if you’re set on running a certain pace for a certain distance. Don’t get hung up on the data and artificially add miles to your training log.
• Tawnee has heard anecdotal evidence that the curved treadmill offers a smoother transition back from injury with less risk of re-injury.
• In regards to Mike’s second question: no, it’s not problematic to train occasionally at a higher metabolic cost.
• To the third question: no! The curved treadmill can be thought of as a hill workout.
• To the fourth question: Curved treadmill over traditional.

Tom B. asks:

Running after meniscus removal?

Hey All,

Love the show.

I’m 60. Been a cyclist for decades. Raced CatIV and masters, Sport class mountain bike for about 10 years.  Started running 3 years ago and have done a couple Oly and 1/2 distance Tri’s

Developed knee pain last year and eventually had my knee scoped (after 9 months of working with a PT) I was shocked when the surgeon told me that he’d removed ‘about 70%’ of my medical meniscus.

I want to start running again, but the information I find about the subject seems to be all over the road.

What do you guys say?

What the Coaches say:

• It’s risky, but you don’t necessarily have to throw in the towel.
• You’re probably going to have knee pain while you run… is it worth it to you?
  • But you might not have pain… you’ll never know unless you try.
• Try coming back to running with an anti-gravity treadmill to slowly ease back to running with your fully body weight.
• Check out this study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2603439/
  • While the probability for early degenerative OA in the post-meniscectomy population is substantial, it is a probability and not a certainty.
  • Chatain et al 30 actually found an OR of 0.3 for preoperative participation in sport indicating that it may in fact be protective against OA.
  • McKinley et al 24 measured in vitro changes in tensile, compressive, and shear forces on trabecular bone, with the meniscus intact and following partial and total meniscectomy. Following partial meniscectomy, no significant differences were noted in load transfer through to trabecular bone. In contrast, total meniscectomy caused significant changes in all three types of forces, measured at all levels of the trabecular bone.
  • While meniscectomy clearly alters the biomechanics of the knee joint, it should be noted that degenerative changes in articular cartilage cannot be attributed solely to these biomechanical changes. The literature supports the paradigm that degenerative knee OA has a complex and not fully known etiology41–46.
  • While biomechanical changes due to meniscectomy play a significant role, age-related tissue changes41,42, trauma or wear and tear2,41,42,46,47,49–53, gender41,44,54,55, individual genetic predisposition for developing OA41,52,56,57, and obesity58–62 may also play a significant role.
  • Running and OA?
    • The authors concluded that 40 years of running at 20–40 kilometers per week did not lead to osteoarthritic degeneration in individuals without underlying problems from pre-existing lower extremity injury.
    • While not without disagreement, the literature does not point to running, in and of itself, on healthy knees as a significant risk factor for OA. Rather, pre-existing OA, high BMI, and female gender is correlated with a higher risk for degenerative changes2,65,79,80,84.
  • Current evidence suggests that meniscectomy may be, in itself, a strong risk factor for an increased rate of knee joint degeneration29–34,36,38–40. It is also clear, however, in many cases, that an increased rate of degeneration following meniscectomy is not a certainty30,32,34,36,38–40,47,81. What determines this spectrum of post-surgical outcomes?
• These risk factors are ranked from most frequently to least frequently identified as significant predictors of OA:
  • Quantity of meniscus removed
    • ≥ 1/3 of total
  • Age
    • ≥ 40 years
  • Pre-existing evidence of OA
  • Radiographic
  • Arthroscopic
  • Method of injury
    • Degenerative
  • Gender
    • Female
  • Body Mass Index
    • ≥ 30
  • Compartment
    • Lateral
  • Lower extremity alignment
    • Genu valgum with lateral meniscectomy
    • Genu varum with medial meniscectomy

Piotrek J. asks:

Low cadence and low HR on bike- too low?

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