title: The geometric curvature of the spine during the sirshasana, the yoga's headstand.
abstract: This study analysed the behaviour of the geometric curvature of the spine during sirshasana. The position of dorsal retroreflective markers was computed via stereophotogrammetric analysis in six males and five females (29.4 ± 8.8 years, 63.0 ± 11.4 kg, 1.66 ± 0.08 m [average ± standard deviation]). The spinal points were projected onto the sagittal and frontal planes of the trunk, a polynomial was fitted to the data and the two-dimensional geometric curvature was quantified. The inferior lumbar lordosis decreased compared to the orthostatic position and gait, which may favour the posterior protrusion of the lumbar spinal nucleus pulposus in people with posterior herniation. The lateral deviation at the middle of the thoracic spine increases during sirshasana, which may reflect increased difficulties for postural control and spinal loads. It could be useful for promoting positive spinal structural and functional chronic adaptations for healthy participants, if the yoga programme is carefully planned and the spinal alignment is carefully monitored during a headstand. However, it may aggravate some spinal diseases, especially scoliosis.
authors.affiliation: a Laboratório de Avaliação do Movimento Humano, Faculdade de Educação Física e Dança , Universidade Federal de Goiás , Goiânia , Brazil.
authors.forename: Mário Hebling
authors.initials: MH
authors.lastname: Campos
authors.affiliation: a Laboratório de Avaliação do Movimento Humano, Faculdade de Educação Física e Dança , Universidade Federal de Goiás , Goiânia , Brazil.
authors.forename: Nayane Martins
authors.initials: NM
authors.lastname: Giraldi
authors.affiliation: b Faculdade de Educação Física e Dança , Universidade Federal de Goiás , Goiânia , Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: Gentil
authors.affiliation: c Setor de Fisiologia Humana e do Exercício, Faculdade de Educação Física e Dança , Universidade Federal de Goiás , Goiânia , Brazil.
authors.forename: Claudio Andre Barbosa
authors.initials: CA
authors.lastname: de Lira
authors.affiliation: b Faculdade de Educação Física e Dança , Universidade Federal de Goiás , Goiânia , Brazil.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Vieira
authors.affiliation: a Laboratório de Avaliação do Movimento Humano, Faculdade de Educação Física e Dança , Universidade Federal de Goiás , Goiânia , Brazil.|d Ciência e Tecnologia de Goiás , Instituto Federal de Educação , Goiânia , Brazil.
authors.forename: Marcelo Costa
authors.initials: MC
authors.lastname: de Paula
mesh_terms: D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D010780:Photogrammetry; D011187:Posture / Q000502:physiology*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D015013:Yoga
keywords: Vertebral column; biomechanics; exercise; geometric curvature; kinematics; posture