Gait and Posture 10 (1999) 171–181 Technical note Spatial-temporal parameters of gait: reference data and a statistical method for normality assessment V. Macellari a , C. Giacomozzi a, *, R. Saggini b a Biomedical Engineering Laboratory, Istituto Superiore di Sanita, Viale Regina Elena, 299 -00161 Rome, Italy b Department of General Kinesitherapy, Uniersity G. DAnnunzio, Chieti, Italy Accepted 6 May 1999 Abstract Spatial and temporal parameters of gait are of recognised clinical relevance in the assessment of motor pathologies, because they normally occur in established combinations which can be altered by pathologies. The data collected from 596 healthy subjects have been used to establish relationships among these parameters and a procedure to estimate deviation from normality based on the comparison between measured values and values estimated by exploiting these relationships. The applied multiple linear regression method (MLRM) was preliminarily validated by comparing its outputs with those of corresponding equations found in the literature, and by applying it to a control group of 12 healthy subjects. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Biomechanics; Gait analysis; Statistical models www.elsevier.com/locate/gaitpost 1. Introduction Movement analysis features a set of methodologies that are effective to quantify motor impairments. Among these gait analysis has received the greatest attention and nowadays it exploits a good number of instruments developed to the purpose in the last 20 years. They range from simple foot-switches and elec- trogoniometers, to sophisticated, computer-managed pressure platforms, force platforms, and optoelectronic motion analysers. When using these devices the availability of reference data, or rather a reference knowledge base, is essential for impairment assessment. In general, such references are scarce or altogether lacking. This is still true for spatial-temporal parame- ters of gait, despite their wide use which results from the simplicity and the low cost of the required instruments. Some of the difficulty found in defining normal value ranges is due to the intrinsic variability of human gait, which can be overcome only with the evaluation of mean values for each subject and with the analysis of a wide population sample. In addition, as recognised since the 1960s, normal ranges of single parameters do not constitute a sufficient reference base, but it is essential to determine whether and how some parame- ters, i.e. velocity, walking cycle and swing phase-occur in normal combinations [1]. Grieve and Gear [2] iden- tified the following relationships between step frequency ( f ) and velocity (V ): f = 1 ·(V ) + 1 (1) f = 2 ·(V ) 2 (2) where f is expressed as the number of complete cycles per minute, V is normalised with respect to subject height and expressed as height/s. The same authors proposed a third equation that states a linear relation- ship between swing time (t s ) and cycle time (T ), parameters that in this paper are reported as swing phase and walking cycle, respectively (see appendix for definitions): * Corresponding author. Tel.: +39-06-49902864/49902089; fax: + 39-06-49387079. E-mail address: cgiacomo@iss.it (C. Giacomozzi) 0966-6362/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII:S0966-6362(99)00021-1