Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Nov 4:4:2100608.
doi: 10.1109/JTEHM.2016.2623787. eCollection 2016.

Effects of Real-World Versus Virtual Environments on Joint Excursions in Full-Body Reaching Tasks

James S Thomas  1 , Christopher R France  2 , Samuel T Leitkam  3 , Megan E Applegate  1 , Peter E Pidcoe  4 , Stevan Walkowski  5
Affiliations

Effects of Real-World Versus Virtual Environments on Joint Excursions in Full-Body Reaching Tasks

James S Thomas et al. IEEE J Transl Eng Health Med. .

Abstract

Starting from an upright standing posture and reaching for a target that requires some forward bending of the trunk can involve many different configurations of the trunk and limb segments. We sought to determine if configurations of the limb and trunk segments during our standardized full-body reaching tasks were influenced by the visual environment. This paper examined movement patterns of healthy participants ([Formula: see text], eight female and nine male) performing full body reaching tasks to: 1) real-world targets; 2) virtual targets presented on a 3-D television; and 3) virtual targets presented using a head-mounted display. For reaches performed in the virtual world, the avatar was presented from a third-person perspective for the 3-D television and from a first-person perspective for the head-mounted display. Reaches to virtual targets resulted in significantly greater excursions of the ankle, knee, hip, spine, and shoulder compared with reaches made to real-world targets. This resulted in significant differences in the forward and downward displacements of the whole-body center of mass between the visual environments. Visual environment clearly influences how subjects perform full-body reaching tasks to static targets. Because a primary goal of virtual reality within rehabilitation is often to restore movement following orthopedic or neurologic injury, it is important to understand how visual environment will affect motor behavior. The present findings suggest that the existing game systems that track and present avatars from a third-person perspective elicit significantly different motor behavior when compared with the same tasks being presented from a first-person perspective.

Keywords: Full-body reaching; kinematics; trunk control; virtual reality.

PubMed Disclaimer

Figures

FIGURE 1.
FIGURE 1.
Target locations are standardized based on an individual’s hip height, trunk length, and arm length such that the high target could be reached, with the shoulder flexed to 90 degrees and the elbow extended, simply by flexing the hips 15 degrees. The middle and low targets could, in theory, be reached by flexing the hips 30 and 60 degrees respectively.
FIGURE 2.
FIGURE 2.
Effects of visual environment on hand position at target contact.
FIGURE 3.
FIGURE 3.
Effects of visual environment on hand path from initial posture till target contact.
FIGURE 4.
FIGURE 4.
Interaction of gender and visual environment on A) ankle excursions and B) knee excursions.
FIGURE 5.
FIGURE 5.
Effects of visual environment on joint excursions of the hip, spine, and shoulder.
FIGURE 6.
FIGURE 6.
Effects of visual environment on the posture adopted at target contact.
FIGURE 7.
FIGURE 7.
Effects of visual environment on displacement of whole-body center of mass.
See this image and copyright information in PMC

References

    1. Thomas J. S., Corcos D. M., and Hasan Z., “Effect of movement speed on limb segment motions for reaching from a standing position,” Experim. Brain Res., vol. 148, no. 3, pp. 377–387, 2003. - PubMed
    1. Thomas J. S., Corcos D. M., and Hasan Z., “Kinematic and kinetic constraints on arm, trunk, and leg segments in target-reaching movements,” J. Neurophysiol, vol. 93, pp. 352–364, Jan. 2005. - PubMed
    1. Thomas J. S. and Gibson G. E., “Coordination and timing of spine and hip joints during full body reaching tasks,” Human Movement Sci., vol. 26, no. 1, pp. 124–140, Feb. 2007. - PMC - PubMed
    1. Thomas J. S. and France C. R., “Pain-related fear is associated with avoidance of spinal motion during recovery from low back pain,” Spine, vol. 32, pp. E460–E466, Jul. 2007. - PubMed
    1. Thomas J. S., France C. R., Lavender S. A., and Johnson M. R., “Effects of fear of movement on spine velocity and acceleration after recovery from low back pain,” Spine, vol. 33, no. 5, pp. 564–570, Mar. 2008. - PubMed