Fujita Y1,2, Nishimaru Y1, Yamada M1, Lutton M2, Mishima A3, Mikami A4
1Morinomiya Hospital, Osaka, Japan, 2Bobath Memorial Hospital, Osaka, Japan, 3Intermediate Nursing Home Greenlife, Osaka, Japan, 4Chubu Gakuin University, Gifu, Japan
Background: People often fall when the rotation of the body is required in transfer activity or in changing the direction of movement. Barin et al (1997) and William et al (2006) reported the significant increase of the postural sway with the head extension.Fujita et al (WCPT 2015) reported that the correlation between the direction of head rotation and the direction of sway and Fujita et al (ACPT 2016) also reported that the magnitude of posturalsway was not correlated with the magnitude of head rotation in healthy adults. Thus the rotation of the head must be one of the factors to break the balance of the standing posture.
Purpose: The objective of this study was to examine the contribution of trunk and pelvic rotation to the postural sway with head rotation.
Methods: Twelve healthy volunteers (7 males and 5 females, age ranged 22-38 years old) were participated in this study. Each subject was tested 3 head rotation conditions with 20°, 30° and 40° of rotation. The auditory signal was given every 3 seconds to tell the timing of the head rotation to the subject. The acceleration was measured with the acceleration sensor (TSND121, ATR-Promotions Co. Ltd., Kyoto）placed at the forehead, trunk, and pelvic position of each subject. The body sway was measured with the posturographysystem (Gravicorder GP-3000, Anima, Tokyo) and
(1) totallength,
(2) envelopment area and
(3) rectangle area were calculated.
Between each condition, subjects took a rest for 3 minutes. The Welch's t-test was used for statistical analyses.
Results: The peak value of the head acceleration was significantly larger (p 0.01)in 40 deg (17208.7±3453.6 rad/s) and 30 deg (13954.2±2626.7 rad/s) compared with 20 deg (9971.4 ±1925 rad/s) conditions. Magnitude of trunk acceleration and pelvic acceleration were correlated (r2=0.94).On the other hand, the magnitude of trunk and pelvic acceleration was not correlated with the magnitude of head acceleration. In other word, trunk and pelvic were relatively stable independent to the magnitude of head rotation. The postural sway was not significantly different depend on the amount of rotation. In addition to this, a center of gravity shifted toward the anterior and contralateral direction in all rotation conditions.
Conclusion(s): In spite of the increase of the amplitude and the acceleration of the head rotation, the postural sway,magnitude of trunk and pelvic acceleration did not different significantly in healthy subjects. The contribution of the body mechanisms to reduce the posturalsway was expected from our results. The control of the contralateral lower limb may be important during the rotation of head.
Implications: In the clinical treatment, the training of the balance control, trunk and pelvic alignment with dynamic head rotation must be effective to reduce the risk of falls.
Keywords: Head rotation, Acceleration,, Center of gravity
Funding acknowledgements: None
Purpose: The objective of this study was to examine the contribution of trunk and pelvic rotation to the postural sway with head rotation.
Methods: Twelve healthy volunteers (7 males and 5 females, age ranged 22-38 years old) were participated in this study. Each subject was tested 3 head rotation conditions with 20°, 30° and 40° of rotation. The auditory signal was given every 3 seconds to tell the timing of the head rotation to the subject. The acceleration was measured with the acceleration sensor (TSND121, ATR-Promotions Co. Ltd., Kyoto）placed at the forehead, trunk, and pelvic position of each subject. The body sway was measured with the posturographysystem (Gravicorder GP-3000, Anima, Tokyo) and
(1) totallength,
(2) envelopment area and
(3) rectangle area were calculated.
Between each condition, subjects took a rest for 3 minutes. The Welch's t-test was used for statistical analyses.
Results: The peak value of the head acceleration was significantly larger (p 0.01)in 40 deg (17208.7±3453.6 rad/s) and 30 deg (13954.2±2626.7 rad/s) compared with 20 deg (9971.4 ±1925 rad/s) conditions. Magnitude of trunk acceleration and pelvic acceleration were correlated (r2=0.94).On the other hand, the magnitude of trunk and pelvic acceleration was not correlated with the magnitude of head acceleration. In other word, trunk and pelvic were relatively stable independent to the magnitude of head rotation. The postural sway was not significantly different depend on the amount of rotation. In addition to this, a center of gravity shifted toward the anterior and contralateral direction in all rotation conditions.
Conclusion(s): In spite of the increase of the amplitude and the acceleration of the head rotation, the postural sway,magnitude of trunk and pelvic acceleration did not different significantly in healthy subjects. The contribution of the body mechanisms to reduce the posturalsway was expected from our results. The control of the contralateral lower limb may be important during the rotation of head.
Implications: In the clinical treatment, the training of the balance control, trunk and pelvic alignment with dynamic head rotation must be effective to reduce the risk of falls.
Keywords: Head rotation, Acceleration,, Center of gravity
Funding acknowledgements: None
Topic: Human movement analysis; Musculoskeletal
Ethics approval required: Yes
Institution: Bobath memorial hospital
Ethics committee: Ethics Committee of Bobath memorial hospital
Ethics number: 10
All authors, affiliations and abstracts have been published as submitted.
