An orthosis including an ankle joint device (52, 116, 137, 162, 243) comprising an ankle joint body (54, 117, 168); a first attachment member (59, 127, 166, 247) pivotally connected to the joint body, for pivotal movement about a generally horizontal axis in a dorsiflexion direction and a plantarflexion direction opposite to the dorsiflexion direction; a plantarflexion resistance spring (88, 184) configured to bias the first attachment member in a dorsiflexion direction relative to the ankle joint body when the first attachment member is within a plantarflexion resistance spring active angular range, the plantarflexion resistance spring active angular range beginning at a plantarflexion resistance spring recruitment angle and increasing in plantarflexion therefrom; and a dorsiflexion resistance spring (50, 96, 98, 124, 128, 172, 174) configured to bias the first attachment member in a plantarflexion direction relative to the joint body when the first attachment member is within a dorsiflexion resistance spring active angular range, the dorsiflexion resistance spring active angular range beginning at a dorsiflexion resistance spring recruitment angle and increasing in dorsiflexion therefrom; a second attachment member (58, 125, 164, 245) connected to the ankle joint body about a generally horizontal axis; wherein one of the first attachment member and the second attachment member is configured for attachment to a lower leg of a human wearer of the device, and the other is being configured for attachment to a foot of a human wearer of the device characterised in that the second attachment member is pivotally connected to the ankle joint body and the orthosis includes further a second attachment member locking mechanism operable to lock the second attachment member at a selected angle relative to the ankle joint body. an ankle joint device (52, 116, 137, 162, 243) comprising an ankle joint body (54, 117, 168); a first attachment member (59, 127, 166, 247) pivotally connected to the joint body, for pivotal movement about a generally horizontal axis in a dorsiflexion direction and a plantarflexion direction opposite to the dorsiflexion direction; a plantarflexion resistance spring (88, 184) configured to bias the first attachment member in a dorsiflexion direction relative to the ankle joint body when the first attachment member is within a plantarflexion resistance spring active angular range, the plantarflexion resistance spring active angular range beginning at a plantarflexion resistance spring recruitment angle and increasing in plantarflexion therefrom; and a dorsiflexion resistance spring (50, 96, 98, 124, 128, 172, 174) configured to bias the first attachment member in a plantarflexion direction relative to the joint body when the first attachment member is within a dorsiflexion resistance spring active angular range, the dorsiflexion resistance spring active angular range beginning at a dorsiflexion resistance spring recruitment angle and increasing in dorsiflexion therefrom; a second attachment member (58, 125, 164, 245) connected to the ankle joint body about a generally horizontal axis; wherein one of the first attachment member and the second attachment member is configured for attachment to a lower leg of a human wearer of the device, and the other is being configured for attachment to a foot of a human wearer of the device characterised in that the second attachment member is pivotally connected to the ankle joint body and the orthosis includes further a second attachment member locking mechanism operable to lock the second attachment member at a selected angle relative to the ankle joint body.