Standing with one foot in front of the other (sharpened romberg position) : footedness effect

Introduction

The Sharpened Romberg (SR) procedure is one of the most common clinical tests used for the evaluation of postural stability [1]. This consists of narrowing the patient’s base of support by placing feet in a heel to toe position. Nonetheless, test instructions do not specify which foot, preferred or non-preferred, should be placed in front of the other. Much of the evidence [2] available suggests that there is no clear preferred foot in the bilateral context; that is, one foot provides necessary postural support, while the other executes mobilizing action as the complementary action. The purpose of the present study was to investigate footedness effects on the Sharpened Romberg procedure; that is whether placing the preferred or non-preferred foot in front of the other differently affects balance performance.

Methods

Twenty-seven healthy female volunteers (age:21.52.7 years, height:17012 cm weight:59.84.3 kg) were classified in three different foot preference groups: left-footed (n=3), mixed-footed (n=8) and right-footed (n=16) using with the Waterloo Footedness Questionnaire-Revised (WFQ-R) [3]. They were then asked to take up the so-called "sharpened Romberg" position (eyes-closed, duration: 10s) while standing on two adjacent force platforms (ERBE Balance System,
sampling rate: 1000 Hz) under two conditions: (i) the left heel directly in front of the right toes (ii) the right heel in front of the left toes. Balance was assessed in the maximum range (maxCoP) and standard deviation (SDCoP) of the Center of Pressure (CoP) in the anterior/posterior (A/P) and medio/lateral (M/L) directions. Differences between task conditions and footedness groups were assessed using a 2x2 repeated measures ANOVA.

Results

During performance of the SR test, all performers shifted their weight slightly toward the rear foot (approximately 14% difference between the feet) regardless of foot position or footedness group. Maximum range and SD of CoP displacement in the M/L direction significantly increased when positioning the left foot behind the right [maxCoP: F(1,22) = 9.22 p<0.01; SDCoP: F(1,22) = 9.66, p<0.01] (Fig. 1). This effect was similar for both footedness groups as indicated by the lack of any significant group x foot interactions. On the other hand, neither maximum range, nor SD of
CoP displacement along the A/P direction was significantly affected by foot position.