Abstract. The use of locks has a history thousands years. Barbed-spring padlocks are the typical used in ancient China and can be divided into three main types, namely open-keyhole, hidden-keyhole, blocked-keyhole padlocks. Since mechanical structures differ terms opening process, they reconfigurable mechanisms. With combinations changes springs, keys, keyholes, have variety different unlocking...

Age may limit the effect of contextual interference, but the accurate effect of age on contextual interference is not completely identified. Therefore, the purpose of the study was the effect of contextual interference practice orders on acquisition and learning of badminton skills of 45 female students aged from 10 to 12. Participants were randomly assigned to one of the three groups of bloc...