title: Evaluation of Relationship between Trunk Muscle Endurance and Static Balance in Male Students.
abstract: OBJECTIVE
  Fatigue of trunk muscle contributes to spinal instability over strenuous and prolonged physical tasks and therefore may lead to injury, however from a performance perspective, relation between endurance efficient core muscles and optimal balance control has not been well-known. The purpose of this study was to examine the relationship of trunk muscle endurance and static balance.
  
  
  METHODS
  Fifty male students inhabitant of Tehran university dormitory (age 23.9±2.4, height 173.0±4.5 weight 70.7±6.3) took part in the study. Trunk muscle endurance was assessed using Sørensen test of trunk extensor endurance, trunk flexor endurance test, side bridge endurance test and static balance was measured using single-limb stance test. A multiple linear regression analysis was applied to test if the trunk muscle endurance measures significantly predicted the static balance.
  
  
  RESULTS
  There were positive correlations between static balance level and trunk flexor, extensor and lateral endurance measures (Pearson correlation test, r=0.80 and P<0.001; r=0.71 and P<0.001; r=0.84 and P<0.001, respectively). According to multiple regression analysis for variables predicting static balance, the linear combination of trunk muscle endurance measures was significantly related to the static balance (F (3,46) = 66.60, P<0.001). Endurance of trunk flexor, extensor and lateral muscles were significantly associated with the static balance level. The regression model which included these factors had the sample multiple correlation coefficient of 0.902, indicating that approximately 81% of the variance of the static balance is explained by the model.
  
  
  CONCLUSIONS
  There is a significant relationship between trunk muscle endurance and static balance.
authors.affiliation: Shahid Rajaee Physical Education University.
authors.forename: Amirhossein
authors.initials: A
authors.lastname: Barati
authors.affiliation: Department of Sports Medicine, Rasoul Akram hospital, Iran University of Medical Science ; Department of Physical education, Payame Noor University.
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Safarcherati
authors.affiliation: Department of Physical education, Payame Noor University.
authors.forename: Azar
authors.initials: A
authors.lastname: Aghayari
authors.affiliation: Department of Physical Education, Tehran Shahid Rajaee Physical Education University.
authors.forename: Faeze
authors.initials: F
authors.lastname: Azizi
authors.affiliation: Department of Physical Education, Tehran Shahid Rajaee Physical Education University.
authors.forename: Hamed
authors.initials: H
authors.lastname: Abbasi
keywords: Side Bridge Endurance Test; Single-Limb Stance Test; Sorensen Test; Static Balance; Trunk Flexor Endurance Test; Trunk Muscle Endurance