This does seem to be a rather controversial topic for most in the longboard skater community. A lot of us will agree that skating on sliding downhill longboard decks or skate-park riding may involve a good amount of risk-taking. Wearing a helmet can offset such a risk. But, of course, if you are freeriding on the flat at a minimum speed, there is no need really for you to buckle up because as an experienced skater, low speeds and flat grounds do not pose so much a danger as downhill freewheeling. A helmet does reduce the risk of injury to the skull.
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