Technical and measurement report Normative range of weight-bearing lunge test performance asymmetry in healthy adults Matthew C. Hoch * , Patrick O. McKeon Division of Athletic Training, University of Kentucky, College of Health Sciences, Wethington Building, 900 South Limestone, Lexington, KY 40536-0200, USA article info Article history: Received 23 November 2010 Received in revised form 11 February 2011 Accepted 22 February 2011 1. Introduction Reduced dorsiflexion is a clinical consideration during the management and rehabilitation of several lower extremity injuries (Landrum et al., 2008;Youdas et al., 2009). Decreases in dorsiflexion are often the result of triceps surae muscle tightness (You et al., 2009) or local arthrokinematic restrictions in posterior talar glide in reference to the ankle mortise (Denegar et al., 2002). Addition- ally, reduced dorsiflexion has been and identified as a risk factor for sustaining lower extremity injury in military recruits (Pope et al., 1998), male physical education students (Willems et al., 2005), and adult volleyball players (Hadzic et al., 2009). Reduced dorsi- flexion may be modifiable risk factor for lower extremity injury that can be easily identified during clinical examination. The weight-bearing lunge test (WBLT) is a functional and reli- able method to indirectly assess dorsiflexion by measuring the maximal advancement of the tibia over the rearfoot in a weight- bearing position (Bennell et al., 1998). Previous investigators (Bennell et al., 1998;Jones et al., 2005;Vicenzino et al., 2006) have reported robust inter-tester and intersession reliability associated with the assessment of WBLT performance in healthy adults along with a robust correlation(r ¼ 0.95) between degrees of dorsiflexion range of motion and maximal lunge distance. Furthermore, there is a significant positive correlation between WBLT performance and peak ankle sagittal plane kinematics during walking and running (Barrett & Caulfield, 2009); as well as, reach distance on the Star Excursion Balance Test (Hoch et al., 2010b). Lunge distance asymmetries on the WBLT have been used to identify weight-bearing dorsiflexion impairments in individuals with a history of ankle sprain (Beazell et al., 2010;Collins et al., 2004;Grindstaff et al., 2010;Reid et al., 2007;Vicenzino et al., 2006). Previous investigators (Beazell et al., 2010;Collins et al., 2004; Grindstaff et al., 2010;Reid et al., 2007;Vicenzino et al., 2006) delin- eated subjects with minimum lunge distance asymmetry of 1 or 2 cm on the WBLT as having clinically relevant impairments. While these levels of asymmetry have been assumed to represent path- ologic dorsiflexion deficits, the normally-occurring asymmetry exhibited by healthy individuals is currently unknown. Addition- ally, no investigations have examined potential explanatory vari- ables for WBLT performance which could present the opportunity to normalize and enhance this measure’s interpretability. There- fore, the purpose of this investigation was to examine the bilateral symmetry of the WBLT in healthy adults and elucidate the indi- vidual influences of age, height, mass, leg length, foot length, and posterior displacement of the ankle-subtalar-joint-complex on WBLT performance. 2. Methods 2.1. Subjects Thirty-five healthy adults (14 males, 21 females; see Table 1 for subject demographics) volunteered to participate in this cross- sectional study. Prior to enrollment, all subjects provided written informed consent approved by the institutional review board. Subjects reported to the laboratory for a single test session. All subjects reported no history of lower extremity injury in the previous six months, no lower extremity surgery, and no health conditions which may influence foot and ankle function. Addi- tionally, subjects had no self-reported functional loss in the foot or ankle based on the Foot and Ankle Ability Measure (Martin et al., 2005). * Corresponding author. Division of Athletic Training, University of Kentucky, College of Health Sciences, Wethington Building, Room 206B, 900 South Limestone, Lexington, KY 40536-0200, USA. Tel.: þ 1 859 323 1100x80839. E-mail address: mcho222@uky.edu (M.C. Hoch). Contents lists available at ScienceDirect Manual Therapy journal homepage: www.elsevier.com/math 1356-689X/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.math.2011.02.012 Manual Therapy 16 (2011) 516e519