Relationship Between the Kinematics of the Trunk and Lower Extremity and Performance on the Y-Balance Test

Min-Hyeok Kang; Gyoung-Mo Kim; Oh-Yun Kwon; Jong-Hyuk Weon; Jae-Seop Oh; Duk-Hyun An

doi:10.1016/j.pmrj.2015.05.004

Relationship Between the Kinematics of the Trunk and Lower Extremity and Performance on the Y-Balance Test

PM R. 2015 Nov;7(11):1152-1158. doi: 10.1016/j.pmrj.2015.05.004. Epub 2015 May 12.

Authors

Min-Hyeok Kang¹, Gyoung-Mo Kim², Oh-Yun Kwon³, Jong-Hyuk Weon⁴, Jae-Seop Oh⁵, Duk-Hyun An⁶

Affiliations

¹ Department of Physical Therapy, Graduate School, INJE University, Gimhae, South Korea.
² Department of Physical Therapy, BAEKSEOK University, Cheonan, South Korea.
³ Laboratory of Kinetic Ergocise Based on Movement Analysis, Department of Physical Therapy, YONSEI University, Wonju, Gangwon-do, South Korea.
⁴ Department of Physical Therapy, JOONGBU University, Chubu-myeon, Geumsan-gun, Chungcheongnam-do, South Korea.
⁵ Department of Physical Therapy, College of Biomedical Science and Engineering, INJE University 607 Obang-dong, Gimhae-si, Gyeongsangnam-do, South Korea, 621-749.
⁶ Department of Physical Therapy, INJE University, Gimhae, South Korea.

PMID: 25978949
DOI: 10.1016/j.pmrj.2015.05.004

Abstract

Background: The lower quarter Y-balance test (YBT-LQ) has been recommended as a measure of dynamic postural control in the clinical setting; however, information about the relationship between performance on the YBT-LQ and joint kinematics is limited. Thus, the kinematic predictors responsible for performance on the YBT-LQ need to be identified for accurate evaluation of dynamic postural control.

Objectives: To identify the kinematic predictors that best explain variance in performance on the YBT-LQ.

Design: Cross-sectional design.

Setting: University motion analysis laboratory.

Participants: Thirty physically active participants.

Methods: All participants performed the YBT-LQ. The kinematics of the trunk and lower extremity at maximal reach in each direction of the YBT-LQ were monitored using a 3-dimensional motion analysis system.

Main outcome measurements: The correlations between reach distance and joint kinematics were assessed using Pearson's correlation coefficient, and the best predictors of performance on the YBT-LQ were determined using a stepwise multiple regression analysis.

Results: Ankle dorsiflexion was the best single predictor of normalized reach in the anterior direction of the YBT-LQ (r(2) = 0.50), and the combination of ankle dorsiflexion and trunk extension explained 65% of the variance in the anterior normalized reach. Hip flexion was the best single predictor of posteromedial (r(2) = 0.60) and posterolateral (r(2) = 0.71) normalized reaches of the YBT-LQ. The combination of hip flexion and ipsilateral trunk bending and the combination of hip flexion and contralateral trunk bending accounted for 69% and 80% of the variance in the posteromedial and posterolateral normalized reaches of the YBT-LQ, respectively.

Conclusions: These findings provide useful information on the relative contribution of joint kinematics to performance on the YBT-LQ when evaluating dynamic postural control.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Biomechanical Phenomena / physiology
Cross-Sectional Studies
Exercise Test
Female
Humans
Lower Extremity / physiology*
Male
Motor Activity / physiology
Postural Balance / physiology*
Range of Motion, Articular / physiology*
Torso / physiology*
Young Adult