Intra-rater reliability ranged from moderate to almost perfect agreement for joint position error ( ICC0.48-0 .82 ) , the cranio-cervical flexion test ( ICC0 .69 ) , the neck flexor muscle endurance test performed in supine ( ICC0 .68 ) and in a 45-upright position ( ICC0 .41 ) with the exception of a new test ( neck extensor test ) , which ranged from slight to moderate agreement ( ICC = 0.14-0 .41 ) .