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The purpose of the present study was to study the effect of attentional focus instructions on motor skills that requiring near to maximum force production, such as shot put skill. In this experiment, twenty eight right- handed girl students with little shot put experience were selected voluntarily. They divided to two groups (internal and external focus) based on their shot put scores in pre- test (consists of 3 trial). They were asked to shot put using O׳brien technique. Experiment performed in three sessions and each session consists of three trials. Instructions referred specifically either to body movement (internal focus) or to shot (external focus). In this study, mixed ANOVA 2(group) ´ 3(session) with repeated measures on last factor is used for analyzing data. The results of this experiment showed that distance of shot put was greater in external focus group rather than internal focus group. Also interaction between attentional focus and practice session was significant (P< 0/001). In conclusion, external focus resulted in producing greater force relative to internal focus. These findings indicate that previously shown benefits of an external attentional focus generalize to motor skills requiring maximal force production.

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The purpose of this study was to examine the effect of skill level on variability of
intra limb coordination and control variables in top spin strike. The 16 participants
of this study were divided into two groups of Skilled and Novice. The Skilled group
was consisted of players who ranked as 8 top in national ranking at their age stage
and the Novice group was consisted of players who recently learned the top spin
skill. They performed 10 top spin strikes with emphasis on speed and accuracy.
Movement kinematics were recorded and analyzed. There was a difference
between these two groups in variability of intra limb coordination (p<0.05) and the
Skilled group performed more consistent. However, there was not any differences
between these two groups in movement control variables (all p>0.05). This study
showed that the skilled performers have more consistency in their movement
patterns, while it could be no difference with novice performers in control variables
as cause of task constraints.

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The purpose of this study was to investigate the effect of practice variability in physical compared with observational practice on golf putting performance. To this end, 50 male right-handed students (25±3.7 years) of the Ferdowsi University of Mashhad participated in this study. Participants were randomly divided into 5 groups (physical constant, physical variable, observational constant, observational variable, and control). During acquisition, the physical variable group randomly performed 50 trials from 5 different starting points to 2 different targets, but the physical constant group performed 50 trials from one starting point to one predetermined target. The observational variable and constant groups observed the performance of the physical variable and constant groups, respectively. The control group just participated in pre-and post-tests and did not practice any trial. Participants performed a test just like the pre-test 10 minutes and also 24 hours after practice. Putting accuracy was measured as the dependent measure. Results showed that variability of practice had a positive effect on participants’ performance than constant practice in physical and observational conditions (all P<0.05). Maybe the similar underlying mechanisms and also the similar feedback effects resulted in the higher performance of the variable group than the constant group in physical performance and action observation.