Validity and reliability of spatio-temporal gait parameters in adolescents.

Gait is a complex activity based on information captured by periphery receptors and elaborated at the level of central nervous system. The age of 6 years seems to constitute a turning point in locomotor control[. From about 7-8 years of life no difference to the adult pattern could be observed[, even if recent studies have implied that gait maturation may continue beyond the age of 8 years and may not be complete until 13 years of age[. The dynamic baropodometry is used to evaluate adolescent gait in cerebral palsy, idiopathic scoliosis, hip arthrodesis and anatomical alterations of plantar foot[.

The purpose of this study was to recruit twenty-two healthy asymptomatic adolescents (14 boys mean age 13.6±1.6; 8 girls, mean age 12.8±1.2) to determine the reliability in assessing spatiotemporal measurements frequently used in clinical practice.

During a 4 months period, at Department of Orthodontics, University of Palermo, we analysed 22 healthy subjects without orthopaedic, neurological and/or musculo-skeletal problems who needed orthodontic treatment. Written informed consent to participate in the study was obtained. The subjects were tested with an electronic baropodometer (Milletrix System® Roma, Italy) twice at an interval of one week by one clinician to determine test-retest reliability and twice at the same day by two clinicians to determine inter-rater reliability. The test-retest measures of reliability demonstrated moderate-to-good within-session, ranging from 0.62 to 0.99. Very reliable were cadence (left foot ICC = 0,92, 95% CI = 0,32 to 0,89, right foot ICC = 0,95, 95% CI = 0,74- 0,94) and total surface (left foot ICC = 0,96, 95% CI = 0,82-0,97, right foot ICC = 0.91, 95% CI = 0,89-0,92).

The measures of inter-rater reliability demonstrated moderate-to-good levels of reliability, ranging between 0.62 and 0.97. Very reliable were the cadence (left foot ICC= 0.95, 95% CI = 0.37 to 0.90, right foot ICC = 0.92, 95% CI =0.79- 0.97) and walking speed (left foot ICC = 0.90, 95% CI = 0.69 to 0.57, right foot ICC= 0.91, 95% CI = 0.78 to 0.96). The assessment of gait is essentially clinical (physical musculoskeletal and neurological examinations).

Information elicited from dynamic baropodo-metry can be an integral component in the formulation of patient's clinical diagnosis and intervention plans, allowing to investigate the plantar morphology and the distribution of the pressures exerted on the foot plant during gait with its pathological variations and may be helpful in developing and monitoring rehabilitation programs.

The study of the distribution of spatio-temporal parameters during the walking cycle in adolescents can be useful to build orthotic devices, for evaluating surgical techniques (correction of hallux valgus, ankle's peripheral nerves decompression), physical therapeutic intervention's outcome, and plantar sensitivity[ as well as for studying several gait disorders[. For this reason it is necessary to ensure that measurement systems, can accurately capture and reproduce parameters of dynamic foot function on different occasions.

We believe that the electronic baropodometer is a minimally invasive methodology with moderate-good reliability useful for monitoring baropodometric variables in normal adolescent population. We recommend future studies in order to investigate the reliability of baropodometric measurements in a younger group of patients, and to study the influence of puberty and adolescence upon posture.