Browsing by Author "Passos, P."
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- An exploratory approach to capture interpersonal synergies between defenders in footballPublication . Milho, J.; Passos, P.Collective behaviors in football may result from players forming inter¬personal synergies that contribute to performance goals. Due to the huge number of variables that continuously constrain players’ behavior during a game, the way that these synergies are formed remain unclear. In team sports such as football, a common effective defensive tactical strategy is one in that defending players “fill” the space between themselves, disturbing the attackers intentions to get closer to the goal and score. To assemble such situations, we hypothesized that the defenders create a functional synergy, which occurs when components of a system behave as a whole contributing to the development of a specific task (Kelso, 2009). Supported on a previous research in Rugby Union (Passos et al., 2017), we postulate that synergies are—mechanisms that substantiate interpersonal coordination in team sports of Football. It is relevant to state that a general feature of coordination is the mutual dependency among system components (e.g., defenders), which led them to behave (e.g., play) as a whole (Kugler and Turvey, 1987; Kelso, 2009). The creation of a synergy is grounded on a comple¬mentarity between variability and stability, which means that some defending player’s (as components of a system) must vary the manner they interact to stabilize specific performance variables (Black et al., 2007; Passos et al., 2017). On this exploratory study, our aim was to quantify interpersonal synergies in team sport of football, in particular, to quantify dyadic interpersonal synergies between the four field defenders that formed the defensive squad of a football team. We hypothesized that neighboring defending players adjust their relative positions to stabilize an interpersonal distance and as such create interpersonal synergies.
- Are synergies continuously present in cyclical movements? An example with the basketball dribble taskPublication . Robalo, R.; Diniz, Ana; Milho, João; Pitacas, P.; Passos, P.In human movement, synergies occur when two or more variables co-vary to stabilize a performance goal. The concept of motor redundancy is associated with the existence of several strategies to complete the same task, which enables a movement system to adapt to an ever-changing environment. This feature provides the system with the ability of being flexible enough to produce adaptive movements, but also stable enough to produce acceptable outputs which is a key issue in motor performance. In a kinetic chain of movement, two proximal joints might reciprocally compensate to stabilize an end-effector (i.e., the most distal segment in the limb that interacts with the environment). End-effector variables are 'controlled', and directly linked to performance, whereas the task relevant elements are allowed by the system to have high variability, providing adaptability. In basketball dribbling, we hypothesized that shoulder and elbow variability contributes to stabilize the dribble height as an end-effector performance variable. A specific computational procedure based on the UCM (i.e., Uncontrolled Manifold) notion was used to capture synergies in two groups according to the experience level: amateurs and professionals. Results identified synergy presence during the basketball dribbling, which only occurred when the wrist reached its peak height. The control of the wrist peak height is achieved due to a reciprocal compensation between shoulder and elbow which stabilizes the dribbling height.