Gait and Posture 12 (2000) 34–45 Review Symmetry and limb dominance in able-bodied gait: a review Heydar Sadeghi a,b,c,d, *, Paul Allard a,c , Franc ¸ois Prince a,b,c , Hubert Labelle a,b,e a Research Center, Sainte -Justine Hospital, 3175 Co ˆte -Ste -Catherine, Montreal, Quebec, Canada H3T 1C5 b Marie -Enfant Hospital, Rehabilitation Center of Sainte -Justine Hospital, 5200 Be ´langer East, Montreal, Quebec, Canada H1T 1C9 c Department of Kinesiology, Uniersity of Montreal, 2100 Edouard -Montpetit Bld, Montreal, Quebec, Canada H3C 3J7 d Department of Kinesiology, Tarbiat Moallem Uniersity, Ministry of Sciences, Research and Technology, Tehran, I.R. Iran e Department of Orthopedic Surgery, Sainte -Justine Hospital, 3175 Co ˆte -Ste -Catherine, Montreal, Quebec, Canada H3T 1C5 Received 10 November 1999; received in revised form 7 May 2000; accepted 26 May 2000 Abstract As one of the most universal of all human activities, gait in the able-bodied has received considerable attention, but many aspects still need to be clarified. Symmetry or asymmetry in the actions of the lower extremities during walking and the possible effect of laterality on gait are two prevalent and controversial issues. The purpose of this study was to review the work done over the last few decades in demonstrating: (a) whether or not the lower limbs behave symmetrically during able-bodied gait; and (b) how limb dominance affects the symmetrical or asymmetrical behavior of the lower extremities. The literature reviewed shows that gait symmetry has often been assumed, to simplify data collection and analysis. In contrast, asymmetrical behavior of the lower limbs during able-bodied ambulation was addressed in numerous investigations and was found to reflect natural functional differences between the lower extremities. These functional differences were probably related to the contribution of each limb in carrying out the tasks of propulsion and control during able-bodied walking. In current debates on gait symmetry in able-bodied subjects, laterality has been cited as an explanation for the existence of functional differences between the lower extremities, although a number of studies do not support the hypothesis of a relationship between gait symmetry and laterality. Further investigation is needed to demonstrate functional gait asymmetry and its relationship to laterality, taking into consideration the biomechanical aspects of gait. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Gait asymmetry; Limb dominance; Symmetry; Laterality indices www.elsevier.com/locate/gaitpost 1. Introduction Gait is a basic requirement for daily activity [1] and is known to be one of the most universal and complex of all human activities. It is a complex motor skill governed by several inter-linked pathways from the cortex to the muscles [2]. The high interaction between the central nervous system and various muscles allows the individual to keep the body upright, while at the same time moving around in an orderly, stable manner. The interest in asymmetrical gait arises from questions regarding limb coordination in producing the smooth rhythmical motion of the able-bodied. Gait interpreta- tion can be affected by assuming lower limb symmetry, since asymmetry is frequently considered to indicate gait pathology. Therefore, accepting that gait is asym- metrical in the able-bodied population is an important issue for clinicians and may also be an important consideration in physical activities, gait evaluation, clin- ical decisions for patients requiring rehabilitation for one or both lower extremities, and artificial limb design. Our intent in this review paper was to summarize the work done over the last few decades regarding the assumption of lower limb symmetry during able-bodied gait. Limb laterality and its possible effect on the symmetrical or asymmetrical behavior of the lower extremities during gait is also considered. This paper consists of three unequal parts. After defining gait * Corresponding author. Tel.: +1-514-3454931 ext. 6195; fax: +1-514-3454801. E-mail address: sadeghih@ere.umontreal.ca (H. Sadeghi). 0966-6362/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0966-6362(00)00070-9