Core Strength and its Relation to Static and Dynamic Balance

Open Access
Fisler, Anne Elizabeth
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Sayers John Miller Iii, Thesis Supervisor
  • Stephen Jacob Piazza, Honors Advisor
  • Giampietro Luciano Vairo, Faculty Reader
  • Trunk Strength
  • Core
  • Balance
  • Hop
ABSTRACT Core Strength and its Relation to Static and Dynamic Balance Fisler AE Miller SJ, Vairo GL,: Athletic Training Research Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA Objective: Recent evidence has suggested that core stability is a determinant of lower-extremity musculoskeletal injury. However, studies have yet to examine if core stability influences postural control and functional performance in a healthy population. Therefore, the purpose of this study was to investigate the effects of core stability as measured by core endurance strength on measures of postural control via dynamic and static balance in a healthy college-age cohort. It was hypothesized that patients with greater core endurance strength would demonstrate heightened postural control. Design and Setting: Controlled laboratory environment. Subjects: 32 (twenty-two women and 10 men) participants (age = 20.9 ± 0.8 years, height = 1.7 ± 0.09 m, mass = 65.1 ± 13.0 kg, BMI = 22.6 ± 2.6 and RPI = 42.2 ± 1.4) volunteered for this study. No participants presented with a history of previous low back injury, lower extremity injury or cerebral concussion within the preceding six months. Main Outcome Measures: Participants performed four timed isometric core muscle endurance tests (seated flexion, left and right lateral planks and the Biering-Sorensen back extension) for as long as possible. Participants were classified into strong and weak groups according to weather the flexion-to-extension ratio was greater than or less than unity (P < 0.001). A force plate recorded center of pressure data during a static single-leg balance task under eyes open and eyes closed conditions. Averaged maximum distances during a single-legged balance reach task were normalized to the non-stance leg-length (%LL). Averaged maximum distances during a single-legged hop were normalized to leg-length (% LL). Two-sample t-tests were calculated to analyze statistically significant differences between the strong and weak groups for each dependent variable of interest. A probability level of P &#8804; 0.05 was set a priori to denote statistical significance. Results: There was a statistically significant difference between groups for the flexion core endurance strength time (strong = 215.8 ± 79.5s, weak = 104.14 ± 59.1s, P < 0.001). Greater anterior reach distances were achieved by the strong group completing the single-legged balance reach task with the dominant (72.2 ± 3.5 %LL, P = 0.040) and non-dominant (69.8 ± 4.2 %LL, P = 0.050) legs compared to the weak group (dominant = 74.4 ± 4.8 %LL, non-dominant = 71.9 ± 3.7 %LL). Ironically, the weak group demonstrated a lesser path length compared to the strong group with eyes ii closed (81.7 ± 16.6cm, P = 0.002) on the non-dominant leg, eyes open (36.6 ± 7.6cm, P = 0.020) and closed (80.6 ± 21.5cm, P = 0.020) on the dominate leg. Average velocity was significantly slower in the weak group (8.1 ± 2.2cm/s, P = 0.020) for eyes closed on the dominate leg. All other comparisons were not found to be statistically different (P > 0.05). Conclusions: Our study suggests that participants with increased flexion core endurance strength demonstrate a greater degree of dynamic balance during single-legged anterior reaches. It is also suggested that weak participants may adopt compensatory postural control mechanisms different than strong participants to maintain static balance. Word Count: 502