title: Concurrent validity and reliability of using ground reaction force and center of pressure parameters in the determination of leg movement initiation during single leg lift.
abstract: Postural adjustment evaluations during single leg lift requires the initiation of heel lift (T1) identification. T1 measured by means of motion analyses system is the most reliable approach. However, this method involves considerable workspace, expensive cameras, and time processing data and setting up laboratory. The use of ground reaction forces (GRF) and centre of pressure (COP) data is an alternative method as its data processing and setting up is less time consuming. Further, kinetic data is normally collected using frequency samples higher than 1000Hz whereas kinematic data are commonly captured using 50-200Hz. This study describes the concurrent-validity and reliability of GRF and COP measurements in determining T1, using a motion analysis system as reference standard. Kinematic and kinetic data during single leg lift were collected from ten participants. GRF and COP data were collected using one and two force plates. Displacement of a single heel marker was captured by means of ten Vicon(©) cameras. Kinetic and kinematic data were collected using a sample frequency of 1000Hz. Data were analysed in two stages: identification of key events in the kinetic data, and assessing concurrent validity of T1 based on the chosen key events with T1 provided by the kinematic data. The key event presenting the least systematic bias, along with a narrow 95% CI and limits of agreement against the reference standard T1, was the Baseline COPy event. Baseline COPy event was obtained using one force plate and presented excellent between-tester reliability.
authors.affiliation: School of Physical Education, Sport and Exercise and Science, University of Otago, 46 Union St West, P.O. Box 56, Dunedin, New Zealand.
authors.forename: Daniela
authors.initials: D
authors.lastname: Aldabe
authors.affiliation: Center of Health and Sports Sciences, University of the State of Santa Catarina, 386, Pascal Simone Street, CEP 88080-350, Florianopolis, Santa Catarina, Brazil.
authors.forename: Marcelo Peduzzi
authors.initials: MP
authors.lastname: de Castro
authors.affiliation: School of Physical Therapy, College of Medicine, University of Saskatchewan, Andrew's College, 1121 College Drive, Saskatoon, SK S7N 0W3, Canada.
authors.forename: Stephan
authors.initials: S
authors.lastname: Milosavljevic
authors.affiliation: School of Physical Education, Sport and Exercise and Science, University of Otago, 46 Union St West, P.O. Box 56, Dunedin, New Zealand. Electronic address: daldabe@gmail.com.
authors.forename: Melanie Dawn
authors.initials: MD
authors.lastname: Bussey
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006365:Heel / Q000502:physiology; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011312:Pressure; D015203:Reproducibility of Results
keywords: Centre of pressure; Concurrent-validity; Heel lift determination; Motion analyses; Postural adjustment