walkingDoubleSupportPercentage: HealthKit quantity type
HKQuantityTypeIdentifierWalkingDoubleSupportPercentage · read from Apple’s documentation on 2026-10-02
HKQuantityTypeIdentifier.walkingDoubleSupportPercentage (Objective-C HKQuantityTypeIdentifierWalkingDoubleSupportPercentage) is a HealthKit quantity type in Apple's "Mobility" group. Apple's abstract: “A quantity sample type that measures the percentage of time when both of the user’s feet touch the ground while walking steadily over flat ground.” Apple's discussion says its samples use percentage units and measure discrete values, so in HKStatisticsQuery it takes .discreteAverage, .discreteMin or .discreteMax. It is available from iOS 14.0 and watchOS 7.0.
What Apple says walkingDoubleSupportPercentage is
A quantity sample type that measures the percentage of time when both of the user’s feet touch the ground while walking steadily over flat ground.
Apple’s abstract, quoted from its walkingDoubleSupportPercentage reference page, read 2026-10-02. Apple’s discussion of the type runs 166 words.
- Swift
HKQuantityTypeIdentifier.walkingDoubleSupportPercentage- Objective-C
HKQuantityTypeIdentifierWalkingDoubleSupportPercentage- Family
HKQuantityTypeIdentifier- Apple's topic group
- Mobility
- Group page
- Mobility
- Apple's reference
- walkingDoubleSupportPercentage on developer.apple.com
Availability
The versions Apple’s documentation data gives for walkingDoubleSupportPercentage, platform by platform, as read on 2026-10-02.
| Platform | Introduced | Deprecated |
|---|---|---|
| iOS | 14.0 | — |
| iPadOS | 14.0 | — |
| Mac Catalyst | 14.0 | — |
| macOS | 13.0 | — |
| visionOS | 1.0 | — |
| watchOS | 7.0 | — |
The rest of that release: HealthKit Types Introduced in iOS 14.
Sum or average, and in which units
Apple states both of these in the prose of the type’s discussion, not as properties, so they are derived from Apple’s sentence and the sentence is shown with each.
Aggregation style
discrete — in an HKStatisticsQuery, use .discreteAverage, .discreteMin or .discreteMax. Apple’s sentence:
These samples use percentage units (described in ) and measure discrete values (described in ).
Unit family
percentage — every type in this family is on the HKUnit reference.
Apple states it in the same sentence as the aggregation style, quoted above.
Empty parentheses and a dangling “described in” mark links in Apple’s sentence to other documentation pages: the generator keeps the sentence’s text, not its links, and the quote is left as stored rather than repaired.
Can apps write walkingDoubleSupportPercentage?
Apple’s documentation for walkingDoubleSupportPercentage does not state that its samples are read-only. Apple states read-only status only in prose, and its silence is not a statement either way, so this page makes no claim that apps can save it.
On Android Health Connect
No verified Health Connect counterpart. The cross-platform matrix pairs only metrics checked against both Apple’s and Google’s documentation, and walkingDoubleSupportPercentage is not among them. A similarly named Health Connect record may exist, but a name match is not a verified mapping.
Metadata keys Apple ties to it
The HKMetadataKey constants whose own Apple text names walkingDoubleSupportPercentage, with the sentence that does, from Apple’s metadata-key pages read 2026-10-04.
- HKMetadataKeyDevicePlacementSidevalue: NSNumber
For mobility samples, like walkingSpeed or walkingDoubleSupportPercentage, this metadata key records the placement of the device as determined by the system.
Questions
- Should I sum or average walkingDoubleSupportPercentage in HealthKit?
- Average it, or take its minimum or maximum — do not sum it. Apple's documentation for walkingDoubleSupportPercentage describes it as measuring discrete values, so an HKStatisticsQuery over it takes .discreteAverage, .discreteMin or .discreteMax. Apple's sentence, as read on 2026-10-02: "These samples use percentage units (described in ) and measure discrete values (described in )."
- Which unit family does Apple give walkingDoubleSupportPercentage?
- Percentage. Apple's discussion of walkingDoubleSupportPercentage says its samples use percentage units: "These samples use percentage units (described in ) and measure discrete values (described in )."
- Which HealthKit metadata keys mention walkingDoubleSupportPercentage?
- HKMetadataKeyDevicePlacementSide. Apple's text for HKMetadataKeyDevicePlacementSide: "For mobility samples, like walkingSpeed or walkingDoubleSupportPercentage, this metadata key records the placement of the device as determined by the system."
- Which iOS version added walkingDoubleSupportPercentage?
- iOS 14.0. Apple's availability data for walkingDoubleSupportPercentage lists iOS 14.0, iPadOS 14.0, Mac Catalyst 14.0, macOS 13.0, visionOS 1.0 and watchOS 7.0.
Sources checked
- Apple — HKQuantityTypeIdentifier.walkingDoubleSupportPercentage · read 2026-10-02
- Apple — HKQuantityTypeIdentifier · read 2026-10-02
- Apple — HKMetadataKeyDevicePlacementSide · read 2026-10-04
Apple’s abstract and sentences are quoted for identification; the page layout, the capsule and the cross-platform pairing are AIFitnessAPI’s. Generated from Apple’s documentation by scripts/fetch-healthkit-identifiers.mjs, not typed by hand — the same data as the full identifier table.