Capturing complex human behaviors in representative sports contexts with a single camera

Ricardo Duarte¹, Duarte Araújo¹, Orlando Fernandes², Cristina Fonseca¹, Vanda Correia¹, Vítor Gazimba², Bruno Travassos^{1, 3}, Pedro Esteves¹, Luís Vilar¹, José Lopes¹

¹Faculty of Human Kinetics, Technical University of Lisbon, Lisbon, Portugal, ²School of Science and Technology, University of Évora, Évora, Portugal, ³Faculty of Social and Human Sciences, University of Beira Interior, Covilhã, Portugal

Key words: TACTO device; direct linear transformation; representative sports contexts; complex behavior.

Summary. Background and objective. In the last years, several motion analysis methods have been developed without considering representative contexts for sports performance. The purpose of this paper was to explain and underscore a straightforward method to measure human behavior in these contexts.

Material and methods. Procedures combining manual video tracking (with TACTO device) and bidimensional reconstruction (through direct linear transformation) using a single camera were used in order to capture kinematic data required to compute collective variable(s) and control parameter(s). These procedures were applied to a 1vs1 association football task as an illustrative subphase of team sports and will be presented in a tutorial fashion.

Results. Preliminary analysis of distance and velocity data identified a collective variable (difference between the distance of the attacker and the defender to a target defensive area) and two nested control parameters (interpersonal distance and relative velocity).

Conclusions. Findings demonstrated that the complementary use of TACTO software and direct linear transformation permit to capture and reconstruct complex human actions in their context in a low dimensional space (information reduction).

Correspondence to R. F. L. Duarte, Faculdade de Motricidade Humana, Estrada da Costa, 1495-688 Cruz Quebrada, Portugal. E-mail: rduarte@fmh.utl.pt

Received 17 May 2010, accepted 7 June 2010