title: Behavioral Dynamics in Swimming: The Appropriate Use of Inertial Measurement Units.
abstract: Motor control in swimming can be analyzed using low- and high-order parameters of behavior. Low-order parameters generally refer to the superficial aspects of movement (i.e., position, velocity, acceleration), whereas high-order parameters capture the dynamics of movement coordination. To assess human aquatic behavior, both types have usually been investigated with multi-camera systems, as they offer high three-dimensional spatial accuracy. Research in ecological dynamics has shown that movement system variability can be viewed as a functional property of skilled performers, helping them adapt their movements to the surrounding constraints. Yet to determine the variability of swimming behavior, a large number of stroke cycles (i.e., inter-cyclic variability) has to be analyzed, which is impossible with camera-based systems as they simply record behaviors over restricted volumes of water. Inertial measurement units (IMUs) were designed to explore the parameters and variability of coordination dynamics. These light, transportable and easy-to-use devices offer new perspectives for swimming research because they can record low- to high-order behavioral parameters over long periods. We first review how the low-order behavioral parameters (i.e., speed, stroke length, stroke rate) of human aquatic locomotion and their variability can be assessed using IMUs. We then review the way high-order parameters are assessed and the adaptive role of movement and coordination variability in swimming. We give special focus to the circumstances in which determining the variability between stroke cycles provides insight into how behavior oscillates between stable and flexible states to functionally respond to environmental and task constraints. The last section of the review is dedicated to practical recommendations for coaches on using IMUs to monitor swimming performance. We therefore highlight the need for rigor in dealing with these sensors appropriately in water. We explain the fundamental and mandatory steps to follow for accurate results with IMUs, from data acquisition (e.g., waterproofing procedures) to interpretation (e.g., drift correction).
authors.affiliation: Centre d'Etudes des Transformations des Activités Physiques et Sportives (CETAPS EA3832), Faculty of Sport Sciences, University of Rouen Normandy, Mont Saint AignanFrance; Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM), Department Sciences and Mountain (SceM), University Savoie Mont Blanc, Le Bourget-du-LacFrance.
authors.forename: Brice
authors.initials: B
authors.lastname: Guignard
authors.affiliation: Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM), Department Sciences and Mountain (SceM), University Savoie Mont Blanc, Le Bourget-du-Lac France.
authors.forename: Annie
authors.initials: A
authors.lastname: Rouard
authors.affiliation: Centre d'Etudes des Transformations des Activités Physiques et Sportives (CETAPS EA3832), Faculty of Sport Sciences, University of Rouen Normandy, Mont Saint AignanFrance; Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM), Department Sciences and Mountain (SceM), University Savoie Mont Blanc, Le Bourget-du-LacFrance.
authors.forename: Didier
authors.initials: D
authors.lastname: Chollet
authors.affiliation: Centre d'Etudes des Transformations des Activités Physiques et Sportives (CETAPS EA3832), Faculty of Sport Sciences, University of Rouen Normandy, Mont Saint Aignan France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Seifert
keywords: aquatic environment; behavioral adaptability; coordination variability; human swimming behavior; inertial measurement units; swimming monitoring