Evidence for Specificity of Training Effect after a Six Week Trunk Stabilization Exercise Program

Abstract

While the popular media is full of claims of the improvements in performance that result from trunk stabilization exercises or "core" training, no conclusive evidence exists to quantitatively show that strength or activity of the trunk musculature influences task performance in commonly-used functional tests and trunk perturbation tests. PURPOSE: To examine the effectiveness of an exercise program that was designed to improve stabilization of the trunk on indices of performance which are associated with improved core stability in healthy, athletic young men. METHODS: 15 male college students [age = 20.9 (1.0) yrs, height = 1818 (55) mm, mass = 84.6 (6.3) kg] with no history of ACL or open abdominal surgery who played football in high school were randomly assigned to one of two exercise groups. Subjects in the resistance training (RT) group performed bilateral resistance exercises with free weights for the upper and lower extremities (3 1-hr sessions per week). Subjects in the trunk stabilization (TS) group performed the same exercises but replaced the first set with a series of trunk stabilization exercises. Core stability and strength tests were administered before and after the 6-week program. RESULTS: At the posttest, the TS group showed increased strength (p ≤ 0.10) compared to baseline in the lateral trunk muscles when exerting a force to the left [73.7 (96.0) N] and right [45.1 (60.9) N] and increased endurance (p ≤ 0.10) of the trunk flexors [137.44 (171.5) sec] and extensors [22.89 (30.8) sec]. The TS group was able to minimize (p ≤ 0.10) anterior and posterior angular displacements of the trunk when tested in a device which suddenly released forces. These changes were not observed in the subjects of the RT group who only improved (p ≤ 0.10) in the broad jump [7.45 (10.61) cm]. CONCLUSIONS: These preliminary results suggest that trunk strength, endurance, and control improve when individuals include trunk stabilization exercises in a whole body resistance exercise program but not with resistance exercises alone. Future studies should investigate other "core" training programs to see if greater gains can be made in core stability and strength. These programs should then be used to investigate effects of "core" training on task performance. Supported by a National Football League Inc. grant