Is Cushioning Good or Bad for Running?

Does better impact protection require more cushioning for running? A compelling study in the journal, PM&R, found that runners in neutral running shoes with more cushioning under the heel had a concerning increase in joint torque at the hips, knees, and ankles as compared with running in minimalist shoes or even running barefoot.

Is Cushioning Good or Bad for Running?
More research is confirming and re-affirming that running shoes with too much cushioning, particularly under the heel, is a source of injury by putting your joint mechanics on a harmful trajectory as compared with running barefoot or in barefoot-like running shoes.

The objective of the study was to build upon earlier reports showing that running shoes with more cushioning under the heel than the front of the shoe is primarily responsible for increasing lower extremity torque beyond tolerance compared to running barefoot.

  • The Brooks Adrenalin was the shoe used in the study and was found to increase knee flexion torque by 36% which forced the quadriceps to work unusually hard. This also increased strain through the patella tendon (knee area) and pressure across the patello-femoral joint (knee-femur junction) as compared with barefoot runners, suggesting that cushioned running shoes are not nearly as effective in protection as thought.
Broorks Adrenaline increases torque in healthy runners
The cushioned shoe, Brooks Adrenaline, used in the study.

Unlike the barefoot runners in the study,  the runners in the Brooks neutral running shoe showed a 38% increase in knee-joint torque, indicative of greater compressive loading on the medial tibiofemoral compartment (knee-femur area)

  • high compressive loading on the medial tibiofemoral compartment is concerning, since this area is highly prone to degenerative changes.
  • degenerative changes to joint and tissue structures are susceptible to arthritis of which running in thick cushioned running shoes plays an active role in accelerating these arthritic risk factors.

Worse still, the researchers found that the Brooks neutral shoe led to a 54% increase in hip internal rotation which increases susceptibility to arthritis in the hip-joint, too!

What all this means is thick cushioned running shoes are well on record for not absorbing impact, but actually creating exponential impact that keeps feeding knee and hip injuries. This is why despite being a multi-billion industry with unlimited research resources behind it, cushioned running shoes are ineffective at reducing harmful impacts, which is why too many runners are still hurting.

If you also look at who gets injured you’ll see that the majority of injured runners are heel strike runners, which was the running style of the runners in the study.

Heel Strike Running Increases Joint Torque

Runners in the Brooks neutral shoe had a longer stride length than the barefoot runners who also landed with a low-impact, more controlled forefoot strike. The researchers also discovered that the mass of the neutral running shoe prompted a heavier foot strike, causing the foot to plow harder onto the ground, which increased torque production even more.

Similar studies (references below article) have also blamed cushioned heeled running shoes for encouraging a force-intensive heel strike landing tied to over-striding as compared with running barefoot, which is well-known to encourage a forefoot strike landing tied to a shorter stride and a higher step-rate (i.e. the feet spend more time in the air than on the ground). Not to mention, barefoot running gives you the best feel of the ground, which does the most good in tightening your balance control, while strengthening the feet on all fronts, making them stronger and more tolerant to adapt to new levels of training. It’s because of the forefoot strike along with its accompanying low impact mechanics that allowed the barefoot runners to produced the greatest reductions in all-around impact than the runners in the Brooks shoes.

The Take Home Message

Statistical data does not lie, but unfortunately shoe companies do, claiming their shoe technology corrects ‘this’ and ‘that’ to allow you to run safer, allegedly. However, to date, no clinical evidence supports that correctional and protective features, such as heel cushioning, prevents injury, or promotes long-term health in runners.

The good news is research has shown that running barefoot or in barefoot-like shoes, which are flatter, more flexible, ergonomic footwear, deliver consistent concrete results proving that increasing your feel of the ground transforms into functional movements that sustains more optimally on the joints. In that light, here are all the evidence-backed reasons barefoot-like running shoes are better than conventional running shoes in every way!

References:

Franz et al. (2008). The influence of arch supports on knee torques relevant to knee osteoarthritis. Med Sci Sports Exerc 40, 913-7.

Kerrigan et  al. (1998). Knee osteoarthritis and high-heeled shoes. Lancet. 9113, 1399-401.

Kerrigan et al. (2005). Moderate-heeled shoes and knee joint torques relevant to the development and progression of knee osteoarthritis. Arch Phys Med Rehabil 86, 871-5.

Kerrigan et al.  (2009). The Effect of Running Shoes on Lower Extremity Joint Torques. PM&R 12, 1058-1063.

Reilly, DT and Martens, M. (1972). Experimental analysis of the quadriceps muscle force and patello-femoral joint reaction force for various activities. Acta Orthop Scand 43, 126-37.
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Bretta Riches

"I believe the forefoot strike is the engine of endurance running..."

BSc Neurobiology; MSc Biomechanics candidate, ultra minimalist runner & founder of RunForefoot. I was a heel striker, always injured. I was inspired by the great Tirunesh Dibaba to try forefoot running. Now, I'm injury free. This is why I launched Run Forefoot, to advocate the health & performance benefits of forefoot running and to raise awareness on the dangers of heel striking, because the world needs to know.
Bretta Riches

P.S. Don't forget to check out the Run Forefoot Facebook Page, it's a terrific place to ask questions about forefoot running, barefoot running and injury. I'm always happy to help!