Understanding MIPS Technology in Helmets: How It Works and What It Protects

MIPS technology in helmets describes a design approach intended to reduce rotational forces on the head during angled impacts. This technology uses a low‑friction layer or slip plane inside a helmet to allow limited relative movement between the helmet shell and the head, aiming to lower rotational acceleration that is associated with certain types of brain injury.

MIPS technology in helmets: definition and origins

MIPS began as a concept developed to mimic a natural protective mechanism: the brain is suspended in cerebrospinal fluid and can move slightly within the skull, reducing injury from rotational forces. The term MIPS stands for "Multi‑directional Impact Protection System," and it originated in Sweden. MIPS systems are used across helmet categories including cycling, skiing, motorcycling, equestrian, and some industrial helmets.

Basic components

A typical MIPS implementation includes a thin, low‑friction layer placed between the helmet shell and the comfort liner or padding. During an oblique impact, the layer is designed to slide several millimeters relative to the outer shell, redirecting or absorbing some rotational energy before it reaches the head.

How it differs from traditional liners

Conventional helmet liners focus primarily on linear impact energy absorption using crushable foam (often expanded polystyrene or similar materials). MIPS adds an engineered slip plane specifically to address rotational kinematics — the twisting and rotational acceleration that occur when impacts are not perfectly head‑on.

How MIPS works and the biomechanics involved

Rotational forces and brain injury mechanics

Impacts that produce rotational acceleration are linked in biomechanics research to diffuse axonal injury and other types of brain strain. Rotational motion can cause shear forces within brain tissue; therefore, reducing rotational acceleration is a logical target in helmet design. Laboratory tests measure rotational acceleration, rotational velocity, and brain strain metrics to evaluate how well a helmet system manages these forces.

Slip‑plane mechanics

When an angled blow strikes a helmet, the outer shell can experience tangential forces. A MIPS slip plane permits a short, controlled relative movement (usually a few millimeters) between shell and head. This motion aims to dissipate a portion of tangential energy and lower the peak rotational acceleration transmitted to the headform during testing scenarios.

Benefits, limitations, and real‑world evidence

Potential benefits

• Reduced rotational acceleration in many laboratory oblique‑impact tests.
• Added protection layer that can complement foam energy absorbers for linear impacts.
• Integration across many helmet styles without substantially changing helmet fit or ventilation.

Limitations and considerations

MIPS is not a stand‑alone solution or a guarantee against concussion or severe brain injury. Real‑world crash dynamics vary widely in impact angle, speed, and secondary impacts. Some studies show measurable reductions in rotational metrics for certain impact conditions, while others indicate smaller or variable benefits depending on helmet model, test setup, and impact scenario. Proper fit, helmet condition, and compliance with relevant safety standards remain critical.

Research and standards context

Peer‑reviewed studies and laboratory testing contribute to understanding MIPS performance. Official helmet safety standards from organizations such as the U.S. Consumer Product Safety Commission (CPSC), ASTM International, Snell Memorial Foundation, and ISO focus largely on linear impact metrics or specific test protocols; rotational testing is increasingly considered but is not uniformly required across all standards. Independent testing labs and some academic groups evaluate rotational performance using headforms instrumented for rotational acceleration and brain strain modeling.

Choosing a helmet with MIPS and certification notes

Fit, certification, and intended use

When selecting a helmet, prioritize correct fit, the helmet’s intended activity rating (e.g., cycling, motorcycling, skiing), and compliance with applicable safety standards (CPSC for many bicycle helmets sold in the U.S., DOT/Snell for motorcycle helmets, and activity‑specific ASTM or EN certifications). A helmet with MIPS can offer additional mitigation of rotational forces, but it should complement — not replace — attention to certification, fit, and helmet maintenance.

Maintenance and replacement

Helmet materials can degrade over time or after significant impacts. Most manufacturers and safety organizations recommend replacing helmets after a major impact or after a specified number of years in service. Follow the helmet maker’s instructions for inspection and replacement intervals.

For authoritative information about traumatic brain injury and prevention, see the Centers for Disease Control and Prevention (CDC) guidance on traumatic brain injury and safety best practices (CDC — Traumatic Brain Injury).

Frequently asked questions

What is MIPS technology in helmets and does it prevent concussions?

MIPS technology in helmets is a slip‑plane system designed to reduce rotational acceleration during angled impacts. While laboratory tests show reductions in certain rotational metrics, MIPS cannot guarantee prevention of concussions because concussions arise from complex combinations of linear and rotational forces, along with individual biological factors.

How much movement does a MIPS layer allow?

A MIPS layer typically allows a few millimeters of relative movement between the helmet shell and the liner. The movement is intentionally limited and controlled to redirect or absorb tangential energy rather than to permit unrestricted motion.

Are helmets with MIPS better than helmets without it?

Helmets with MIPS may reduce rotational forces in some impact scenarios, but overall helmet effectiveness depends on certification, fit, helmet construction, and the specific crash conditions. MIPS is one factor to consider along with other features and certifications.

Do standards require MIPS?

Most major helmet safety standards do not currently require MIPS specifically. Standards organizations set performance criteria and test methods; rotational testing is an area of active research and discussion, and independent labs increasingly include oblique impact protocols when evaluating helmets.

How should a helmet with MIPS fit?

Fit a helmet with MIPS the same way as any other helmet: it should sit level on the head, be snug without pressure points, and the retention system should secure the helmet so it does not shift. Proper fit ensures the slip‑plane and other protective elements function as intended.