• James M Elliott, Shaun P O'Leary, Barbara Cagnie, Gail Durbridge, Lieven Danneels, and Gwendolen Jull.
• Division of Physiotherapy, The University of Queensland, Brisbane, Australia. j.elliott2@uq.edu.au
• Arch Phys Med Rehabil. 2010 Sep 1; 91 (9): 1418-22.

ObjectiveTo evaluate the activity of neck extensor muscles during different extension exercises with muscle functional magnetic resonance imaging (mfMRI).DesignCross-sectional.SettingUniversity laboratory.ParticipantsHealthy subjects (N=11; 7 men, mean age +/- SD, 34+/-5.6y; 4 women, mean age +/- SD, 23.3+/-5.2y; group mean age +/- SD, 30.1+/-7.5y).InterventionNot applicable.Main Outcome MeasuresmfMRI measures of T2 relaxation were made for the multifidus (Mul), the semispinalis cervicis (SCe), the semispinalis capitis (SCa), and the splenius capitis (SpC) at C2-3, C5-6, and C7-T1 in response to 2 head/neck orientations: craniocervical neutral (CCN) and craniocervical extension (CCE). Subjects performed three 1-minute repetitions of each condition at 20% maximum voluntary contraction.ResultsSignificant shifts were observed in all muscle groups at the C5-6 and C7-T1 levels after both conditions (P=.04) except the SpC muscle at C5-6 with CCN (P=.17). T2 shifts in the SCa were significantly greater in response to CCE than CCN at C2-3 (P=.03) and C5-6 (P=.02). Similarly, CCE resulted in larger shifts than CCN in the Mul/SCe at C7-T1 (P=.003). No segmental differences were observed between exercises for SpC (P=.25).ConclusionsThe results of this study provide some preliminary insight into the impact of craniocervical orientation on the differential response of the deep and superficial cervical extensor muscles during the performance of cervical extensor exercises.

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