3D quantitative evaluation of spine proprioceptive perception/motor control through instinctive self-correction maneuver in healthy young subjects' posture: an observational study.

Background: Conservative treatment in spine deformities and spine related disorders is mainly based on proper individual proprioceptive and motor control training. For these reasons, conservative treatment involves the stimulation of individual capability of perceiving/reducing deformities, blocks and/or improper spine posture by voluntary control. The literature describes that habitually adopted relaxed postures often exacerbate low back pain. Typically, youths can be referred to therapeutic programs aimed at improving the quality of body posture along with fostering the awareness of the importance of correct posture. Few studies in literature outline the subject's individual instinctive ability to perceive properly and control his/her posture and produce an improvement through a self-correction maneuver.

Aim: How do healthy young adult subjects perceive and control their posture and spine shape? Are they able to modify them in a correct way through an instinctive self-correction maneuver?

Design: Cross-sectional observational study.

Setting: A cohort of asymptomatic young adult university students and workers were recruited at Clinic of Rehabilitation, University of Medical Sciences, Poznan, Poland.

Population: One hundred and twenty-one healthy subjects (57 females, 64 males), aged 19-34 years (mean age: 23.5±3.2 years).

Methods: Subject's full body posture including 3D spine shape reconstruction, identified using 27 retro-reflective markers suitably located on anatomical landmarks has been measured by using a non-ionizing 3D optoelectronic stereo-photogrammetric approach and a 3D full skeleton biomechanical model.

Results: From the 3D full skeleton and spine reconstruction, eleven quantitative biomechanical parameters describing the nature of body posture have been computed to compare natural erect versus self-corrected standing attitudes. A great number of healthy participants (105, 87%) was unable to modify its spinal shape in the frontal plane. Conversely, the sagittal plane presented significant clinical changes in the thoracic spine, as males reached a greater thoracic spine extension (36.4±8.3) than females (40.8±8.7). When changes occurred, subjects were not able to focus and control their posture globally, but only on few aspects at a time.

Conclusions: Instinctive posture proprioception and motor control do not produce an effective self-correction maneuver yielding a global improvement of body posture and spine shape.

Clinical Rehabilitation Impact: Self-correction maneuver producing an improvement of body posture and spine shape has to be learned with specific postural training. The 3D stereo-photogrammetric approach is effective in quantitatively describe subject's posture, motor control and proprioceptive capability.