changing the words and phrases of their verbal instruc- tions, thus influencing their motor performance and learning in different ways (Beilock, Carr, Macmahon, & Starkes, 2002; Wulf, 2013). Studies on the focus of attention have sought to define attention instructions from two perspectives. The first perspective developed by Wulf and her students studies the focus of attention from both internal and external points of view (Wulf, 2013). Most of the studies conducted using such a perspective have demonstrated the advantage of the external focus of attention (Saemi, Abdoli, Farsi, & Sanjari, 2017). The second perspective developed by Beilock et al. (2002) mainly concerns the effect of attention on motor performance focusing on task-relevant and task- irrelevant aspects attentional cues (Beilock, Berten- thal, McCoy, & Carr, 2004; Beilock & Carr, 2001; Cas- taneda & Gray, 2007; Gray, 2004). Under conditions of task-relevant attention, the performer consciously focuses his/her attention on the aspects related to the task being performed (e.g., the movement of the hands Introduction Defined as the level of awareness of the environment, attention is one of the brain’s most crucial cognitive functions playing a key role in performing motor skills (Wulf, 2007). Given the importance of attention strat- egies for the enhanced performance of motor skills, researchers in motor behavior and sport psychology have made considerable efforts to understand what attentional styles lead to success in sport (Wulf, 2013). One of the subjects of interest to researchers in motor behavior in recent years has been the impact of various attention strategies on motor behavior (Wulf, 2013). According to attentional focus literature, the coach or therapist can focus the performer’s attention on particular aspects of the skill being performed just by * Address for correspondence: Esmaeel Saemi, Department of Sport Psychology, Faculty of Sport Sciences, Shahid Chamran University of Ahvaz, Golestan Blvd., Ahvaz, 61357-83151 Iran. E-mail: e.saemi@scu.ac.ir The effect of task-relevant and task-irrelevant attentional cues and skill level on performance and knee kinematics of standing long jump Ayoub Asadi 1 , Esmaeel Saemi 2, *, Mahmoud Sheikh 1 , and Mehdi Takhtaei 1 1 Faculty of Sport Sciences, University of Tehran, Tehran, Iran; and 2 Faculty of Sport Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran Copyright: © 2018 A. Asadi et al. This is an open access article licensed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). Background: Attention is one of the brain’s most crucial cognitive functions playing a key role in performing motor skills. Objective: The purpose of the present study was to investigate the effect of task-relevant and task-irrelevant attentional cues and skill level on performance and knee kinematics of standing long jump. Methods: Fifteen skilled (volleyball and basketball players) and fifteen novices (aged 19 to 27 years) were recruited. The task was the standing long jump test which was executed 9 times under 3 conditions (3 trials per condition). Participants in the control condition did not receive any attentional instruction. In task-relevant attentional cues condition, participants were instructed to focus on their ongoing skill and avoid paying attention to matters unrelated to the task. In task-irrelevant attentional cues condition, participants were instructed to focus on sound and after each jump expressed what had been the musical content. Kinematic data of knee joint was recorded by an 8-camera motion analysis system. Results: The result of mixed ANOVA showed that both novice and skilled groups had significantly greater jump distance and smaller initial knee angle in task-irrelevant attentional cues condition compared to task-relevant attentional cues condition (p = .001) and control condition (p = .001). There were no significant differences between the control and task-relevant attentional cues condition (p > .05). Conclusions: The result showed that focusing attention on task- irrelevant attentional cues improves standing long jump performance of both novice and skilled jumpers. Keywords: attentional strategies, underlying mechanism, skilled, novice, motor control Acta Gymnica, vol. 48, no. 3, 2018, 103–108 doi: 10.5507/ag.2018.015