A friend just told me about a relatively new bike helmet technology that reduces torsion (rotational) stress in a bike accident. My wife is a speech therapist (and I write speech therapy software) so I'm well aware that tearing is more damaging than concussive forces.

It's called MIPS: Multi-directional Impact Protection System.

But, I'm not convinced the MIPS system actually improves on that. The only independent research I've seen a citation to is in swedish. And the next best research was on motorcycle helmets

  • To my knowledge (based on googling around recently when buying a new helmet), there isn't really much info on this sort of stuff specific to bicycles (which is different than other sports and motorcycles).
    – Batman
    Aug 15, 2015 at 15:16
  • Are you asking for evidence from use rather than theory, since the theory seems to be sound? Or are you questioning the theory?
    – Móż
    Aug 17, 2015 at 4:33
  • 1
    The question is if a MIPS hamlet is safer than a regular helmet, correct?
    – ebrohman
    Aug 17, 2015 at 14:19
  • Given is hard to consensus on if helmets are safer than no helmets, I can't see how you could get consensus on if one type is better than another.
    – mattnz
    Aug 18, 2015 at 4:04
  • Related: bicycles.stackexchange.com/q/77213
    – MaxD
    Jun 7, 2021 at 14:50

3 Answers 3



Research into brain injuries has been ongoing, but tended to focus more on direct impacts. In the last 70 years there has been more research into rotational brain injuries, and in the 1990s and 2000s scientific, evidence based proposals were made to reduce these. The Multi-Directional Impact ­Protection System is an implementation of these, and it's effectiveness has been validated by independent research.


There is lots of research into brain injury. While much of it has focused on direct impact leading to scull fracture, the effects of sudden head rotation have been studied since the 1940s. These (pay-walled papers) are typical

Such studies progressed to proposals, such as

[In] 2008 ... Swedish neurosurgeon Hans Von Holst, along with mechanical engineer Peter Halldin, developed a new technology called MIPS (Multi-Directional Impact ­Protection System).

A couple of (non independent) articles are

Mips has been received with acclaim

There has been at least one study of their effectiveness

But not everyone is convinced regarding helmet effectiveness. For a helmet skeptic's view see

Certainly, more independent validation would be good, and in future better designs could appear. At present MIPS seems to set the brain protection benchmark.

  • 1
    the skeptical link is from 2003 and does not mention MIPS, just bike helmets in general. Since MIPS is fairly new (much newer than 12 years I think) then this probably is not referring to MIPS Aug 18, 2015 at 18:55
  • Thanks for the extensive searching Andy, that's really helpful. And I read the "skeptic" link as actually supporting MIPS, since it talks about helmets that are not designed to mitigate rotation as being a problem... to which MIPS is a solution.
    – Móż
    Aug 19, 2015 at 2:08
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    @Rider_X Thanks .. updating to just say a helmet skeptic's view.
    – andy256
    Aug 19, 2015 at 5:39
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    Here's a more recent skeptic's view on MIPS, although it's mostly a critique of another article. The part most pertinent to MIPS, not covered in the articles above: "in the real world, bicycle helmets are so loosely coupled with the head that a slip-plane inside the helmet structure does not add significant sideways movement in an impact. The helmet moves anyway, unless it is constrained in a lab test. " bhsi.org/bicyclingmag1305.htm
    – Karen
    Aug 19, 2015 at 16:24
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    The Swedish insurance company Folksam has done testing on some helmets with MIPS, and at a first glance it seems they result in less rotational acceleration: folksam.se/media/… May 17, 2018 at 9:11

Oblique is a common type of impact. How would reducing torsion stress not be a good thing?

Do you question if MIPS reduces torsion stress or if reducing torsion stress protects the brain?

An oblique impact results in a rotational force to the head/brain. I would not characterize that as tearing. The brain is not a muscle. This is a study / paper that the human brain is most sensitive to rotational motion

  • 1
    Lots of tissues can tear. You can tear a muscle, a cartilage, an artery, a vein ... The paper you link mentions tearing of veins that bridge the subdural space.
    – andy256
    Aug 15, 2015 at 23:04
  • @andy256 Well my link totally discredits the answer. Thank you for not down voting.
    – paparazzo
    Aug 15, 2015 at 23:38
  • @Frisbee, that's a good article but the second part of my question is "do these helmets actually help"? Any thoughts? Aug 18, 2015 at 0:46
  • It looks like the point of contention is whether or not the helmet actually reduces the types of injuries associated with oblique impact. Aug 18, 2015 at 1:06
  • 1
    @StephenTouset Address the OP
    – paparazzo
    Aug 18, 2015 at 1:39


Conclusion, they test with computer models and dummies which don't have hair and their scalp doesn't move... Soo, unless your bald, your hair is MIPS.

  • Actually, it's your scalp that acts in a manner similar to MIPS, and MIPS is based on how the scalp functions.
    – Rider_X
    Feb 10, 2016 at 22:27
  • This link is actually well worth a read. It discusses the potential use of slip planes, existing alternatives and potential problems with current approaches. The conclusion drawn here is way oversimplified though.
    – Lukas
    Sep 5, 2017 at 7:35

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