The Big Team Challenge app for iOS and Android requests several permissions, all of which are optional.
Push notification permission for delivery updates from the organiser
Photo library access to allow the user to upload an optional profile photo
Health Connect and Apple Health permissions to sync steps and distance
Health Connect requests only the user’s step count which comes under the physical activity permission. The user can revoke this via the Health Connect app at any time.
Apple Health requests the user’s step count and walking/running distance. This can be revoked at any time via the phone’s Settings app (in the Privacy, then Health sub-sections).