Motor control and biomechanical analysis of forward bending with knees extended and flexed

Shioto Fukushima

    Research output: ThesisDoctoral Thesis

    209 Downloads (Pure)


    [Truncated abstract] Forward bending is a combination of spinal flexion and pelvic rotation/hip flexion, and is a common element in many activities of daily living, labour intensive workplaces and sports. People with pathological spinal conditions often find forward bending is limited by pain or fear of pain. In clinical practice, the range and quality of forward bending and the replication of symptoms is often used as a method of assessment. Therefore, many studies have used this movement to investigate the mechanism of spinal pain syndromes, and have indicated the importance of forward bending for mechanistic and diagnostic research. This thesis focused on two aspects of forward bending to investigate factors that influence spinal kinematics and motor control. Firstly, the perception of body position and kinaesthesis was determined by using assessment of spinal position sense. Secondly, the kinematics of the thoracic and lumbar spine, pelvis and hip were derived from their movement profiles. A series of 4 studies were undertaken to examine both motor control and mechanical characteristics of normal healthy subjects performing the forward bending movement pattern. A common theme of the thesis is the assessment of this movement pattern with the knees extended or slightly flexed. This paradigm was used to examine how slight changes in knee posture may impact on the variability of the movement pattern in normal healthy participants. Study 1 investigated the effect of range of forward bending and different lower limb postures on spinal re-positioning sense in normal control subjects (n = 23). Three-dimensional motion analysis assessed accuracy and precision (variability of error) relative to three targets at different ranges of forward bending (inner range = 20%, mid-range = 50% and outer range = 80% of forward bending range) during spinal flexion movements in sagittal and combined planes with the knees straight and bent. Active position replication was conducted in a balanced randomised order for the three ranges on 10 trials for each range. Accuracy and precision of spinal position sense was measured over increasing trials to examine the optimal number of trials required to generate a more sensitive protocol. The findings suggested that across ten matching trials, there was no learning effect and that the coefficient of variation and statistical power for the accuracy and precision tended to stabilise after six trials. The results of this methodological aspect of the study clearly demonstrate that the increasing the number of trials, from the usual research practice of three, used in spinal position sense testing has a significant impact on the sensitivity of this assessment and improves the potential to detect differences between people with and without spinal disorders.The findings of this study suggest that in normal subjects 6 or more matching trials for spinal re-position sense testing should be conducted to derive both 3D accuracy and precision scores...
    Original languageEnglish
    QualificationDoctor of Philosophy
    Publication statusUnpublished - 2009


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