Unipedal postural stability in nonathletes with core instability after intensive abdominal drawing-in maneuver

The exact neuromechanical nature and relative contribution of the abdominal drawing-in maneuver (ADIM) to postural instability warrants further investigation in uninjured and injured populations. To determine the effects of the ADIM on static core and unipedal postural stability in nonathletes with core instability. Controlled laboratory study. University research laboratory. A total of 19 nonathletes (4 women: age = 22.3 ± 1.3 years, height = 164.0 ± 1.7 cm, mass = 56.0 ± 4.6 kg; 15 men: age = 24.6 ± 2.8 years, height = 172.6 ± 4.7 cm, mass = 66.8 ± 7.6 kg) with core instability. Participants received ADIM training with visual feedback 20 minutes each day for 7 days each week over a 2-week period. Core instability was determined using a prone formal test and measured by a pressure biofeedback unit. Unipedal postural stability was determined by measuring the center-of-pressure sway and associated changes in the abdominal muscle-thickness ratios. Electromyographic activity was measured concurrently in the external oblique, erector spinae, gluteus medius, vastus medialis oblique, tibialis anterior, and medial gastrocnemius muscles. All participants initially were unable to complete the formal test. However, after the 2-week ADIM training period, all participants were able to reduce the pressure biofeedback unit by a range of 4 to 10 mm Hg from an initial 70 mm Hg and maintain it at 60 to 66 mm Hg with minimal activation of the external oblique (t(18) = 3.691, P = .002) and erector spinae (t(18) = 2.823, P = .01) muscles. Monitoring of the pressure biofeedback unit and other muscle activations confirmed that the correct muscle contraction defining the ADIM was accomplished. This core stabilization was well maintained in the unipedal-stance position, as evidenced by a decrease in the center-of-pressure sway measures (t(18) range, 3.953-5.775, P < .001), an increased muscle-thickness ratio for the transverse abdominis (t(18) = -2.327, P = .03), and a reduction in external oblique muscle activity (t(18) = 3.172, P = .005). We provide the first evidence to highlight the positive effects of ADIM training on core and postural stability in nonathletes with core instability.