Joint rotation torques during a common turning task

Orendurff, Michael S.; Schoen, Jason A.; Glaister, Brian C.; Bernatz, Greta C.; Huff, Elizabeth; Segal, Ava D.; Klute, Glenn K.

doi:10.1016/j.gaitpost.2006.11.139

Cited by 7 publications

(7 citation statements)

References 3 publications

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“…The NA peak positive and negative rotation moments during a turn, ML GRI and stride length measurements were similar to previously reported literature on turning biomechanics in nonamputee subjects walking a constant speed 1 m radius turn [7] and the rotation moments of the apex step during transient turns [14]. Another study that examined ML GRI during the apex step of a transient turn in non-amputees [17] reported larger impulse measurements which may be due to these subjects walking at different speeds [7].…”

Section: Discussionsupporting

confidence: 87%

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Comparison of transtibial amputee and non-amputee biomechanics during a common turning task

et al. 2011

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Section: Discussionsupporting

confidence: 87%

“…Non-amputees also apply transverse plane rotation moments to the ground to change body orientation [14]. However, transtibial amputees may use different biomechanical strategies to complete a turn.…”

Section: Introductionmentioning

confidence: 99%

Comparison of transtibial amputee and non-amputee biomechanics during a common turning task

et al. 2011

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“…Such turning behaviour requires generation of torque around a vertical axis, but other studies of locomotor turning suggest this occurs primarily during single stance, when the body is free to rotate around the stance leg (Xu et al . 2006; Orendurff et al . 2006).…”

Section: Discussionmentioning

confidence: 99%

Vertical torque responses to vestibular stimulation in standing humans

Reynolds¹

2011

The Journal of Physiology

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Non-technical summary Galvanic vestibular stimulation (GVS) is a method for activating the human vestibular nerve with electricity. It induces sensations of head movement which cause sway and eye movements, and affect navigation. GVS is used here to demonstrate a novel vestibular reflex. Stimulation of standing subjects caused them to generate torque around a vertical axis, resulting in trunk rotation. Response magnitude and direction were systematically altered by head orientation in a manner consistent with GVS causing a sensation of head roll. This is relevant for balance control because vestibular information is only useful for fall prevention when interpreted in the context of head orientation. These findings therefore provide a method for investigating this neural transformation process. This can be used to diagnose deficiencies in the vestibular control of balance caused by ageing and/or neurological disease.Abstract The effects of electrical vestibular stimulation upon movement and perception suggest two evoked sensations: head roll and inter-aural linear acceleration. The head roll vector causes walking subjects to turn in a direction dependent on head pitch, requiring generation of torque around a vertical axis. Here the effect of vestibular stimulation upon vertical torque (T z ) was investigated during quiet stance. With the head tilted forward, square-wave stimuli applied to the mastoid processes evoked a polarity-specific T z response accompanied by trunk yaw. Stochastic vestibular stimulation (SVS) was used to investigate the effect of head pitch with greater precision; the SVS-T z cross-correlation displayed a modulation pattern consistent with the head roll vector and this was also reflected by changes in coherence at 2-3 Hz. However, a separate response at 7-8 Hz was unaffected by head pitch. Head translation (rather than rotation) had no effect upon this high frequency response either, suggesting it is not caused by a sense of body rotation induced by an inter-aural acceleration vector offset from the body. Instead, high coherence between medio-lateral shear force and T z at the same frequency range suggests it is caused by mechanical coupling to evoked medio-lateral sway. Consistent with this explanation, the 7-8 Hz response was attenuated by 90 deg head roll or yaw, both of which uncouple the inter-aural axis from the medio-lateral sway axis. These results demonstrate two vertical torque responses to electrical vestibular stimulation in standing subjects. The high frequency response can be attributed to mechanical coupling to evoked medio-lateral sway. The low frequency response is consistent with a reaction to a sensation of head roll, and provides a novel method for investigating proprioceptive-vestibular interactions during stance.

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“…By controlling walking speed, differences found for l between adapters were likely attributed to a change in local stability and not a change in speed. Also, a constant radius turn (similar to the continuation step of a 901 hallway turn) represented a typical-sized turn found in daily ambulation, yet minimized the confounding effects of acceleration and deceleration that have been reported during hallway turns (Orendurff et al, 2006b). However, it is important to note that this task was merely a single subset of turning gait and therefore, may not be representative of all types of turns that occur during daily ambulation.…”

Section: Data Collectionmentioning

confidence: 99%