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. 2022 Dec 1;17(12):e0274717. doi: 10.1371/journal.pone.0274717

An external focus of attention enhances table tennis backhand stroke accuracy in low-skilled players

Tomasz Niźnikowski 1,*, Weronika Łuba-Arnista 2,*, Paweł Arnista 2, Jared M Porter 3, Hubert Makaruk 1, Jerzy Sadowski 1, Andrzej Mastalerz 4, Ewelina Niźnikowska 5, Andrew Shaw 3
Editor: Danica Janicijevic6
PMCID: PMC9714895  PMID: 36455038

Abstract

The aim of the study was to determine the impact of internal and external (proximal and distal) attentional focus on table tennis backhand stroke accuracy in low-skilled players. Fifty-one undergraduate physical education (PE) students were randomly assigned to 3 groups: Group G1 (IF) was instructed to focus on the hand holding the paddle, Group G2 (EFP) was instructed to focus on the ball, while Group G3 (EFD) was instructed to focus on targets marked on the tennis table. The experimental groups followed identical instructions except for the instruction about the focus of attention. Participants were asked to score as many points as possible by hitting the ball inside the three smallest targets marked on the tennis table. They were required to do so using a backhand stroke. The practice session consisted of 45 trials in three blocks of backhand (15 trials at each target). A special scoring system was used to determine the accuracy of the strokes. One of the most important findings from the current research was that groups with an external focus of attention revealed significant improvements in accuracy in the post-test, while the group with an internal focus of attention achieved low training effects. No significant difference was observed between G2 (EFP) and G3 (EFD) in the delayed retention test, which indicates that proximal and distal attentional focus had similar effects on table tennis backhand stroke accuracy in low-skilled players.

Introduction

The effectiveness of motor learning has been analyzed from a number of different scientific perspectives, e.g., behavioural, socio-cognitive, neurophysiological or neurocomputational [1]. There are a lot of factors that affect motor skill acquisition, e.g., variable vs. constant practice, blocked vs. random practice, self-controlled practice, simple vs. complex movement task, learner’s level of advancement, external vs. internal attentional focus instructions, augmented feedback or observational learning [1, 2]. Providing instructions to a learner during motor learning is a common practice used by teachers or coaches. These instructions can be described as associative (i.e., focusing on bodily sensation) and dissociative (i.e., blocking out sensations resulting from physical effort), broad and narrow, or external (i.e., toward the effect of the movement) and internal (i.e., toward the body movement [1–4]. In the literature there is solid evidence that an external focus of attention enhances motor outcomes more substantially than an internal focus of attention. It has been shown in a variety of tasks such as a balance task [5], discus throwing performance [6], standing long jump [7], sprint performance [8], tennis skills technique [9] accuracy tasks in hitting golf balls [10, 11], basketball free throw shooting [12, 13], dart throwing [14, 15], frisbee flying-disk throwing [16] or archery shooting [17]. Wulf and Lewthwaite proposed the Optimizing Performance through Intrinsic Motivation and Attention for Learning (OPTIMAL) theory of motor learning [1]. They suggest that motivational and external attentional factors contribute to successful outcomes in motor learning by strengthening the coupling of performers’ goals to their movement actions.

The effects of focus of attention in motor learning and performance are explained by the “constrained action hypothesis” [18, 19]. According to this theory, an internal focus of attention may interfere with automatic motor control processes. In contrast, an external attentional focus may lead to enhanced effectiveness and efficiency of movement by allowing automatic control. It is important to note that an external focus of attention may be directed close to the body (proximal) or farther away from the body (distal) [2]. Generally, the distal attentional focus is more easily distinguished from one’s own body movements than the proximal focus of attention, which leads to increased performance improvement [20]. This is confirmed by studies conducted with novice performers in dart throwing [21] and standing long jump [22]. However, Singh and Wulf [23] claim that the optimal distance of external focus of attention depends on the level of expertise. Low-skilled practitioners benefit the most from a proximal external focus, whereas a distal focus of attention is more appropriate for high-skilled performers. This assumption is in line with Roberts and Lawrence’s research results [24]. They showed that in an aiming task, using a proximal external focus of attention led to better outcomes.

In summary, it is unclear which type of external attentional focus (proximal or distal) is more beneficial in applied experiments with performers of different levels of expertise [4]. Thus, further research in this vein is recommended. In addition, Keller et al. [25] suggest that racquet sports may be better suited for inducing an external focus of attention during training due to the instrumentation with external targets. Unfortunately, insufficient research has been conducted on attentional focus in racquet sports (e.g., badminton, table tennis, squash, tennis, etc.). Therefore, the aim of this experiment was to determine the impact of internal and external (proximal and distal) attentional focus on table tennis backhand stroke accuracy in low-skilled players.

Materials and methods

Fifty-one right-handed participants (n = 12 women, n = 39 men, age 22.9 ± 1.8 years, body mass 71.2 ± 9.7 kg, height 176 ± 8.5 cm) were recruited from undergraduate physical education (PE) courses. They enrolled in table tennis classes (thirty 45-minute sessions) as part of the university curriculum. The sample size in the current study was selected based on sample sizes in similar studies (n = 11 [11], n = 10 [16], n = 10 [6]). Power analysis of the current research using G*Power Version 3.1.9.4 [26] showed that with an estimated moderate effect size, it was determined that a minimum of twelve participants were required in each group (effect size = 0.25, power = 0.80, p = 0.05), so the recruited sample of seventeen participants in each group was considered appropriate.

The participants were required to have no lower or upper extremity injury over the last 3 months, and no previous organized table tennis training. Each participant was considered a low-skilled player who had basic understanding and skills of table tennis strokes, and all were naive to the study purpose. The participants were randomly assigned to one of the three practice groups: G1 (IF)–with a focus of attention on the hand holding the paddle (n = 17; age 22.4 ± 1.4 years, body mass 71.9 ± 10.4 kg, body height 175 ± 8.3 cm), G2 (EFP)–with a focus of attention on the ball (n = 17, age 23.1 ± 1.7 years, body mass 72.4 ± 10.5 kg, body height 175.8 ± 9.2 cm) and G3 (EFD)–with a focus of attention on targets marked on the tennis table (n = 17, age 23.2 ± 2.2 years, body mass 69.4 ± 8.4 kg, body height 177.1 ± 8.2 cm). Each group was equal in terms of the gender of the participants. All participants delivered written informed consent prior to the commencement of the experiment. Ethical approval was provided by the Senate Scientific Research Ethics Committee of Lomza State University of Applied Sciences (document code: 4175500, 22.11.2021).

The participants performed a pre-test, a practice phase and a post-test on the same day. The retention test was conducted 24 hours after the practice phase. During the tests and the practice phase, the participants were instructed to score as many points as possible by hitting the ball inside the three smallest targets marked on the tennis table (targets 1, 2, 3) (Fig 1).

Fig 1. Target location on the tennis table (number: 1, 2, 3).

Fig 1

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The practice session consisted of 45 trials in three blocks (15 trials at each target). Also, during each test all the participants completed 45 trials in three blocks. The participants were required to perform backhand strokes. The experimental groups followed a similar experimental design, with one difference–instructions concerning the focus of attention were provided in the practice phase only (no attentional focus instructions were given in the pre-test or post-test). Participants from group G1 (IF) were instructed to “concentrate on the hand holding the paddle”, group G2 (EFP) were told to “concentrate on the ball”, while group G3 (EFD) were asked to “concentrate on targets marked on the tennis table”. The experimenter gave attentional focus reminders at the beginning of each block. On each test day, the participants performed a 15-minute warm-up routine (running and flexibility exercises). A 30-second break was provided after each block. The post-test was administered immediately after the practice session. No attentional focus instructions or reminders were given in the retention test to assess relatively permanent effects of the instructions.

The experiment was conducted on consecutive days in a sports hall and was performed on a standard-size tennis table approved by the International Table Tennis Federation (ANDRO Magnum SC, Germany). Each of the participants used the same professional paddle with the following characteristics: blade (ANDRO "Inizio ALL", Germany) and rubbers (DONIC "Liga", 2.0 mm, Germany). Plastic table tennis balls (DONIC "Coach ** P40+ Cell-Free", Germany) were delivered to the participants by a table tennis robot (NEWGY Robo-Pong 1050, DONIC, Newgy Industries Inc., Tennessee, USA) positioned in the middle of the table, on the opposite side of the participant. The robot was programmed as follows: ball speed (level 13), frequency–the time between balls served (1.5 s; 40 balls/min), rotation type (topspin), the angle of the robot head (level 6), the ball placement on the table (for backhand strokes–left and right position: level 3). The assessment developed by Poolton et al. [27] was used to determine the accuracy of the strokes during the pre-test, post-test and retention test (Fig 1).

On the table opposite the participant, there were six squares (50 cm per side) and three smaller squares (25 cm per side) centrally located inside the furthest squares (targets 4, 5, 6) (Fig 1). Three points were awarded when the ball landed on the smallest targets (targets 1, 2, 3), two points were awarded when the ball hit into the large distal squares surrounding the smallest targets, and one point was awarded if the ball hit inside the three large proximal squares. The participants received no points if the ball did not hit any of the squares. In total, they performed 45 trials (15 trials per one target). Shots that landed in target number 3 scored 3 points, those in number 6 = 2 points, and those in number 9 = 1 point, while balls landing in all other squares scored 0 points. The points were summed across all strokes to determine the final performance score. The reliability of this test was confirmed by the value of the intra-class correlation coefficient (ICC = 0.92; excellent agreement) [28]. A single player with 17 years of table tennis experience recorded the points scored for all tests of every participant. No feedback about errors was provided to the participants other than the knowledge of results available to them by performing the task.

Prior to conducting the analysis, all data was checked to ensure it satisfied parametric assumptions of normality and homogeneity of variance using the Kolmogorov-Smirnov and Shapiro-Wilk tests. All violations of sphericity were corrected by adjusting the degree of freedom using the Greenhouse-Geisser correction when the sphericity estimate was less than 0.75, and the Huynh-Feldt correction when it was greater than 0.75 [29]. Effect sizes were reported using partial eta squared (np2) for all main effects and interactions and Cohen’s d for comparison between two means. Cohen’s d effect sizes were calculated using the following formula: Cohen’s d = M1 –M2/spooled, where spooled = (√S1+S2)/2. Parametric effect sizes were defined as large d > 0.8, moderate 0.8 > d > 0.5 and small d < 0.5 [30]. A reported measures ANOVA was conducted to verify that there were differences in follow-through mean number of points (MNP) depending on the focus of attention on the hand holding the paddle, focus of attention on the ball or focus of attention on targets marked on the tennis table. A further one-way between-participants ANOVA was run on pre-test accuracy scores to ensure there were no differences in performance levels between groups prior to the intervention. A 3 group x 3 period [pre-test, post-test (cumulates/effects), delayed training effects (retention test)] mixed design ANOVA with repeated measures on the last factor was employed to compare differences in MNP. Post-hoc Fisher’s LSD was used to analyze significant main effects and interactions to determine the location of differences within (period) and between (group) factors

Results

All groups performed with similar accuracy (MSP) on the pre-test (Table 1). The analysis of MNP did not reveal a main effect of Group (F(2.48) = 1.249, p = 0.296, η2 = 0.049). Training period (F(2.96) = 50.116, p < 0.001, η2 = 0.511) and the analysis of the interaction of those two factors (F(4.96) = 3.354, p = 0.0129, η2 = 0.123) reached statistical significance.

Table 1. Mean number of points (MNP) in G1, G2 and G3 during the two phases of the experimental design: Pre-acquisition and post-acquisition.

Group Training period Mean SD
G1 (IF) pre-test 71.26 8.08
post-test 75.19 10.28
retention test 82.22 14.51
G2 (EFP) pre-test 65.41 14.30
post-test 76.99 13.13
retention test 87.54 15.03
G3 (EFD) pre-test 66.36 13.09
post-test 84.46 19.20
retention test 93.43 10.57
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Training effect

Post-hoc analyses revealed significant improvements in MNP from pre-test to post-test (Table 1) for group G2 (17.7%, d = 0.37, p = 0.001) and for group G3 (27.3%, d = 0.51, p < 0.001), while an insignificant increase in MNP was found for group G1 (5.5%, d = 0.15, p = 0.262). There were no differences in MNP between G1 and G2 (d = 0.21, p = 0.699). The mean number of points in G3 were higher than those in G1 (d = 0.27, p = 0.047).

Delayed training effects/DET/

The analysis of DET revealed significant improvements in MNP over post-test (Table 1) for G1 (9.3%, d = 0.24, p = 0.002), G2 (13.7%, d = 0.31, p < 0.001) and G3 (10.6%, d = 0.29, p < 0.001). Post-hoc analysis indicated that DET results in group G3 were significantly higher compared to G1 (d = 0.34, p = 0.017). There was no significant difference between G3 and G2 (d = 0.17, p = 0.206).

Discussion

The aim of the study was to determine the impact of internal and external (proximal and distal) attentional focus on table tennis backhand stroke accuracy in low-skilled players. Throughout the literature, it has been widely confirmed that an external focus of attention enhances motor outcomes more substantially than an internal focus of attention [2, 4].

One of the most important findings from the current research was that groups with an external focus of attention (G2 and G3) revealed significant improvements in accuracy in the post-test, while the group with an internal focus of attention (G1) achieved a low short-term performance effect. This result is in line with the “constrained action hypothesis” [18, 19], which says that an internal focus of attention leads to conscious motor control which impairs automaticity and reduces movement efficiency [2]. In addition, some scientific evidence reported improved neuromuscular efficiency during an external focus of attention compared to internal focus in such tasks as isokinetic elbow flexions [31], isometric force production tasks [32] or isometric plantar-flexion [33]. Also, it was proved that an external focus of attention enhanced muscular endurance compared with an internal focus [34]. Hatami et al. [35] found that in no instruction situations, shoulder muscle activity did not change significantly as compared with the external focus of attention situation during forehand stroke in table tennis.

Our results showed that external attentional focus instructions accelerate the learning of the motor task so that the learner can achieve a higher skill level sooner [36]. However in the post-test, no significant differences between groups G2 and G1 were observed. Still, significant differences were noted between G3 and G1. Performance at the immediate assessment phase is often not predictive of outcomes at the time of a delayed retention test due to the process of motor memory consolidation [37]. Admittedly, each of the groups significantly improved the accuracy in the delayed retention test over the post-test. It was also noted that the group with a focus of attention on targets (G3) achieved a significant higher outcome than the group with a focus of attention on the hand holding the paddle (G1). This result is consistent with the findings of Chua et al. [38] that a distal external attentional focus facilitates both immediate performance and longer-term learning.

The lack of significant differences between G2 and G3 in the delayed retention test may indicate that both proximal and distal attentional focus is similarly effective in table tennis backhand stroke accuracy in low-skilled players. This finding is contrary to earlier research results that compared distal and proximal attentional focus in motor performance [21–24]. McNevin et al. [20] claim that increasing the distance of the external attentional focus enhanced motor learning. This “distance effect” has also been confirmed in other studies [7, 39, 40]. However, Singh and Wulf [23] claim that in the context of the “distance” of the external attentional focus, it is very important to consider the performer’s skill level. Wulf and Prinz [41] suggest that performers without experience in a specific task might benefit more from a proximal attentional focus because they need to learn basic coordination. In turn, experienced performers might benefit from a distal attentional focus because this situation might facilitate the development of the movement pattern that is necessary to achieve the goal. It may explain the lack of significant differences between G2 and G3 in the delayed retention test. Possibly, the fact that low-skilled performers who had a higher level of physical fitness than less active individuals of the same age were involved in this study could have had an impact on our study result. In addition, our study findings can plausibly be explained in that the focus of attention on the ball that was in motion all the time could be more difficult than the focus of attention on constant targets marked on the tennis table. In practice, PE teachers and coaches working with adolescents can support autonomy by allowing self-definition of success using an external cue to enhance effective goal-action coupling [1].

The limitation of the study is that researchers, coaches and practitioners cannot generalize the results from this analysis of one specific stroke in table tennis to the whole sports discipline. Thus, future studies are recommended to analyze the impact of internal and external (proximal and distal) attentional focus while using other strokes in table tennis. What is more, Razaghi et al. [42] suggest that the combinations of external focus instructions and self-controlled feedback should be used to improve performance and motor learning outcomes. Also, Makaruk et al. [43] propose that a combination of external attentional focus with autonomy support may produce benefits in motor performance. This line of research is worth further investigation in the area of table tennis.

Conclusions

The findings of this study indicate that proximal and distal attentional focus is similarly effective in table tennis backhand stroke accuracy in low-skilled players’ development. Also, these results suggest that table tennis coaches and practitioners can creatively use an external attentional focus to facilitate the performance of motor skills. To date, knowledge about the most effective external attentional focus (proximal or distal) in the performance of complex motor skills by practitioners at different skill levels is incomplete. Further research in this vein is recommended.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Supporting information

S1 File

(XLSX)

Click here for additional data file. (10.3KB, xlsx)

Data Availability

All relevant data are within the paper and its Supporting Information files.

Funding Statement

The authors received no specific funding for this work.

References

  • 1.Wulf G.; Lewthwaite R. Optimizing Performance through Intrinsic Motivation and Attention for Learning: The OPTIMAL Theory of Motor Learning. Psychon Bull Rev 2016, 23, 1382–1414, doi: 10.3758/s13423-015-0999-9 [DOI] [PubMed] [Google Scholar]
  • 2.Wulf G. Attentional Focus and Motor Learning: A Review of 15 Years. Int Rev Sport Exerc Psychol 2013, 6, 77–104, doi: 10.1080/1750984X.2012.723728 [DOI] [Google Scholar]
  • 3.Marchant D.C. Attentional Focusing Instructions and Force Production. Front Psychol 2011, 1, 210, doi: 10.3389/fpsyg.2010.00210 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Nicklas A.; Rein R.; Noël B.; Klatt S. A Meta-Analysis on Immediate Effects of Attentional Focus on Motor Tasks Performance. Int Rev Sport Exerc Psychol 2022, 1–36, doi: 10.1080/1750984X.2022.2062678 [DOI] [Google Scholar]
  • 5.Jackson B.H.; Holmes A.M. The Effects of Focus of Attention and Task Objective Consistency on Learning a Balancing Task. Res Q Exerc Sport 2011, 82, 574–579, doi: 10.1080/02701367.2011.10599791 [DOI] [PubMed] [Google Scholar]
  • 6.Zarghami M.; Saemi E.; Fathi I. External Focus of Attention Enhances Discus Throwing Performance. Kinesiology 2012, 44, 47–51. [Google Scholar]
  • 7.Porter J. M.; Anton P. M.; Wu W. F.W. Increasing the Distance of an External Focus of Attention Enhances Standing Long Jump Performance. J Strength Cond Res 2012, 26, 2389–2393. doi: 10.1519/JSC.0b013e31823f275c [DOI] [PubMed] [Google Scholar]
  • 8.Li D.; Zhang L.; Yue X.; Memmert D.; Zhang Y. Effect of Attentional Focus on Sprint Performance: A Meta-Analysis. Int J Environ Res Public Health 2022, 19, 6254, doi: 10.3390/ijerph19106254 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Tsetseli M.; Zetou E.; Vernadakis N.; Mountaki F. The Attentional Focus Impact on Tennis Skills’ Technique in 10 and under Years Old Players: Implications for Real Game Situations. Journal of Human Sport and Exercise 2018, 13, 328–339, doi: 10.14198/jhse.2018.132.15 [DOI] [Google Scholar]
  • 10.Wulf G.; Su J. An External Focus of Attention Enhances Golf Shot Accuracy in Beginners and Experts. Res Q Exerc Sport 2007, 78, 384–389, doi: 10.1080/02701367.2007.10599436 [DOI] [PubMed] [Google Scholar]
  • 11.Bell J.J.; Hardy J. Effects of Attentional Focus on Skilled Performance in Golf. J Appl Sport Psychol 2009, 21, 163–177, doi: 10.1080/10413200902795323 [DOI] [Google Scholar]
  • 12.Zachry T.; Wulf G.; Mercer J.; Bezodis N. Increased Movement Accuracy and Reduced EMG Activity as the Result of Adopting an External Focus of Attention. Brain Res Bull 2005, 67, 304–309, doi: 10.1016/j.brainresbull.2005.06.035 [DOI] [PubMed] [Google Scholar]
  • 13.Milley K.R.; Ouellette G.P. Putting Attention on the Spot in Coaching: Shifting to an External Focus of Attention With Imagery Techniques to Improve Basketball Free-Throw Shooting Performance. Front Psychol 2021, 12, 918, doi: 10.3389/fpsyg.2021.645676 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Lohse K.R.; Sherwood D.E.; Healy A.F. How Changing the Focus of Attention Affects Performance, Kinematics, and Electromyography in Dart Throwing. Hum Mov Sci 2010, 29, 542–555, doi: 10.1016/j.humov.2010.05.001 [DOI] [PubMed] [Google Scholar]
  • 15.Russell R.; Porter J.; Campbell O. An External Skill Focus Is Necessary to Enhance Performance. J Mot Learn Dev 2014, 2, 37–46, doi: 10.1123/jmld.2014-0038 [DOI] [Google Scholar]
  • 16.Ong N.T.; Bowcock A.; Hodges N.J. Manipulations to the Timing and Type of Instructions to Examine Motor Skill Performance under Pressure. Front Psychol 2010, 1, doi: 10.3389/fpsyg.2010.00196 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Vrbik A.; Vrbik I.; Miholic S.J. External Focus of Attention Enhances Precision in Recreational Archers. Kinesiologia Slovenica 2021, 27, 153–161. [Google Scholar]
  • 18.Wulf G.; McNevin N.; Shea C.H. The Automaticity of Complex Motor Skill Learning as a Function of Attentional Focus. Quarterly Journal of Experimental Psychology Section A: Human Experimental Psychology 2001, 54, 1143–1154, doi: 10.1080/713756012 [DOI] [PubMed] [Google Scholar]
  • 19.Wulf G.; Shea C.; Park J.H. Attention and Motor Performance: Preferences for and Advantages of an External Focus. Res Q Exerc Sport 2001, 72, 335–344, doi: 10.1080/02701367.2001.10608970 [DOI] [PubMed] [Google Scholar]
  • 20.McNevin N.H.; Shea C.H.; Wulf G. Increasing the Distance of an External Focus of Attention Enhances Learning. Psychol Res 2003, 67, 22–29, doi: 10.1007/s00426-002-0093-6 [DOI] [PubMed] [Google Scholar]
  • 21.McKay B.; Wulf G. A Distal External Focus Enhances Novice Dart Throwing Performance. Int J Sport Exerc Psychol 2012, 10, 149–156, doi: 10.1080/1612197X.2012.682356 [DOI] [Google Scholar]
  • 22.Marchant D.C.; Griffiths G.; Partridge J.A.; Belsley L.; Porter J.M. The Influence of External Focus Instruction Characteristics on Children’s Motor Performance. Res Q Exerc Sport 2018, 89, 418–428, doi: 10.1080/02701367.2018.1512075 [DOI] [PubMed] [Google Scholar]
  • 23.Singh H.; Wulf G. The Distance Effect and Level of Expertise: Is the Optimal External Focus Different for Low-Skilled and High-Skilled Performers? Hum Mov Sci 2020, 73, doi: 10.1016/j.humov.2020.102663 [DOI] [PubMed] [Google Scholar]
  • 24.Roberts J.W.; Lawrence G.P. Impact of Attentional Focus on Motor Performance within the Context of “Early” Limb Regulation and “Late” Target Control. Acta Psychol (Amst) 2019, 198, 102864, doi: 10.1016/j.actpsy.2019.102864 [DOI] [PubMed] [Google Scholar]
  • 25.Keller M.; Schweizer J.; Gerber M. Pay Attention! The Influence of Coach-, Content-, and Player-Related Factors on Focus of Attention Statements during Tennis Training. Eur J Sport Sci 2022, 1–9, doi: 10.1080/17461391.2022.2056082 [DOI] [PubMed] [Google Scholar]
  • 26.Faul F.; Erdfelder E.; Lang A.G.; Buchner A. G*Power 3: A Flexible Statistical Power Analysis Program for the Social, Behavioral, and Biomedical Sciences. Behav Res Methods 2007, 39, 175–191, doi: 10.3758/bf03193146 [DOI] [PubMed] [Google Scholar]
  • 27.Poolton J.M.; Masters R.S.W.; Maxwell J.P. The Influence of Analogy Learning on Decision-Making in Table Tennis: Evidence from Behavioural Data. Psychol Sport Exerc 2006, 7, 677–688, doi: 10.1016/j.psychsport.2006.03.005 [DOI] [Google Scholar]
  • 28.Han X. On Statistical Measures for Data Quality Evaluation. Journal of Geographic Information System 2020, 12, 178–187, doi: 10.4236/jgis.2020.123011 [DOI] [Google Scholar]
  • 29.Girden E.R. ANOVA: Repeated Measures; SAGE Publications, Inc.: 2455 Teller Road, Thousand Oaks California 91320 United States of America, 1992; ISBN 9780803942578. [Google Scholar]
  • 30.Cohen J. Statistical Power Analysis for the Behavioral Sciences; 2nd Editio.; Routledge, 1988; ISBN 9780203771587. [Google Scholar]
  • 31.Marchant D.C.; Greig M.; Scott C. Attentional Focusing Instructions Influence Force Production and Muscular Activity during Isokinetic Elbow Flexions. J Strength Cond Res 2009, 23, 2358–2366, doi: 10.1519/JSC.0b013e3181b8d1e5 [DOI] [PubMed] [Google Scholar]
  • 32.Lohse K.R.; Sherwood D.E.; Healy A.F. Neuromuscular Effects of Shifting the Focus of Attention in a Simple Force Production Task. J Mot Behav 2011, 43, 173–184, doi: 10.1080/00222895.2011.555436 [DOI] [PubMed] [Google Scholar]
  • 33.Lohse K.R.; Sherwood D.E. Thinking about Muscles: The Neuromuscular Effects of Attentional Focus on Accuracy and Fatigue. Acta Psychol (Amst) 2012, 140, 236–245, doi: 10.1016/j.actpsy.2012.05.009 [DOI] [PubMed] [Google Scholar]
  • 34.Grgic J.; Mikulic P. Effects of Attentional Focus on Muscular Endurance: A Meta-Analysis. Int J Environ Res Public Health 2022, 19, 89, doi: 10.3390/ijerph19010089 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Hatami M.R.; Sharifmoradi K.; Majlesi M. The Effects of External Focus of Attention on Shoulder Muscle Activities during Forehand Drive in Table Tennis. Journal of Sport Biomechanics 2016, 2, 27–35. [Google Scholar]
  • 36.Wulf Gabriele. Attention and Motor Skill Learning; Human Kinetics, 2007; ISBN 9780736062701. [Google Scholar]
  • 37.Kantak S.S.; Winstein C.J. Learning-Performance Distinction and Memory Processes for Motor Skills: A Focused Review and Perspective. Behavioural Brain Research 2012, 228, 219–231, doi: 10.1016/j.bbr.2011.11.028 [DOI] [PubMed] [Google Scholar]
  • 38.Chua L.-K.; Jimenez-Diaz J.; Lewthwaite R.; Kim T.; Wulf G. Supplemental Material for Superiority of External Attentional Focus for Motor Performance and Learning: Systematic Reviews and Meta-Analyses. Psychol Bull 2021, 147, 618–645, doi: 10.1037/bul0000335.supp [DOI] [PubMed] [Google Scholar]
  • 39.Kearney P.E. A Distal Focus of Attention Leads to Superior Performance on a Golf Putting Task. Int J Sport Exerc Psychol 2015, 13, 371–381, doi: 10.1080/1612197X.2014.993682 [DOI] [Google Scholar]
  • 40.Raisbeck L.D.; Yamada M. The Effects of Instructional Cues on Performance and Mechanics during a Gross Motor Movement. Hum Mov Sci 2019, 66, 149–156, doi: 10.1016/j.humov.2019.04.001 [DOI] [PubMed] [Google Scholar]
  • 41.Wulf G.; Prinz W. Directing Attention to Movement Effects Enhances Learning: A Review. Psychon Bull Rev 2001, 8, 648–660, doi: 10.3758/bf03196201 [DOI] [PubMed] [Google Scholar]
  • 42.Razaghi S.; Saemi E.; Abedanzadeh R. The Effect of External Attentional Focus and Self-Controlled Feedback on Motor Learning in Older Adults. Polish Journal of Sport and Tourism 2020, 27, 9–13, doi: 10.2478/pjst-2020-0002 [DOI] [Google Scholar]
  • 43.Makaruk H.; Porter J.M.; Sadowski J.; Bodasińska A.; Zieliński J.; Niźnikowski T.; et al. The Effects of Combining Focus of Attention and Autonomy Support on Shot Accuracy in the Penalty Kick. PLoS One 2019, 14, doi: 10.1371/journal.pone.0213487 [DOI] [PMC free article] [PubMed] [Google Scholar]

Decision Letter 0

Danica Janicijevic

27 Sep 2022

PONE-D-22-24485An external focus of attention enhances table tennis backhand stroke accuracy in low-skilled playersPLOS ONE

Dear Dr. Tomasz Niznikowski, 

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ACADEMIC EDITOR:Dear authors, Although one of the reviewers considers your article suitable for publication, other for asked major revisions especially directed towards improving the introduction section (considering novel optimal theory on the focus of attention) and clarification of the methodology. 

==============================

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: 1) The text needs to be improved grammatically.

Introduction

2) In the beginning of the Introduction, you are needed to add a brief introduction of various teaching strategies in motor learning. Then you need to enter the attentional focus as an important strategy. And then, please focus on different types of attentional focus (i.e., internal vs. external).

3) Introduction is too weak. The most recent theory on focus of attention is the OTPIAML theory. The authors have not explained this theory in the Introduction. In addition, the novelty of this study is not clear. If using a racquet sport enough for novelty of this experiment. What is the difference between racquet and not-racquet sports? These issues need to be explained more clearly in the Introduction.

Method

4) Why you chose low-skilled players and not absolutely novices?

5) How the students were low-skilled? Were they in the beginnings of semester, mid of semester, or have already finished they courses?

6) Is the info about BMI and etc. important?

7) The info about sample size should be placed in the Participants.

8) The most important issue in your study in attentional focus instructions. However, it is not clear how these instructions were provided and applied. The procedure of this study has not been included. How the participant performed the strokes? If a person from opposite side throws the ball? Or the participant took the ball in his/her hand? Please explain the procedure with all detail.

9) In relation to the comment “8”, it should be said that table tennis is considered as very fast sport, because the acceleration of the ball is very high. My most concern is that how the participates in G2 could concentrate on a ball which moves very fast? I am really confused with choosing this sport for examine proximal and distal effects. It is hard to believe that the participants could focus only on distal distance in table tennis, as the table tennis players focus mostly on balls not on the table. May shooting a basketball could provide more accurate findings.

Results

10) The table 1 looks very simply. Please use different table design.

11) You talked about so many statistical tests; however, they were not reported in the Results?

Discussion

12) It was assumed that the discussion held heavily on the differences between proximal and distal effects in attentional focus. However, based on the Discussion, it is not fully understood why proximal and distal effects are same in this study. Please clarify your findings.

13) Finally, an important reason for the effectiveness of external focus of attention is “goal-action coupling”. However, you have not pointed it in your discussion. Please use it as well as the OPTIMAL theory for discussion your results.

Reviewer #2: This is an appropriate paper I have no hesitation in recommending it. The statistics used are appropriate and the conclusion is consistent and sound. While not entirely novel, it could deserve dissemination across the scientific community. I am looking forward to your future success.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

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Reviewer #1: Yes: Saeed Ghorbani

Reviewer #2: Yes: Rei Odagiri

**********

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PLoS One. 2022 Dec 1;17(12):e0274717. doi: 10.1371/journal.pone.0274717.r002

Author response to Decision Letter 0

2 Nov 2022

RESPONSE TO REVIEWERS COMMENTS

Dear Editor and Reviewers,

The authors would like to thank the reviewers for their precious time and invaluable comments. We have carefully addressed all the comments. The corresponding changes and refinements made in the revised paper are summarized in our response below. We hope that the modifications and explanations will be acceptable to you.

REVIEWER #1

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Response 1: We agree with the reviewer and have made corrections.

Reviewer #2: Yes

Response 1: Thank you for your opinion

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Response 2: Thank you for your opinion

Reviewer #2: Yes

Response 2: Thank you for your opinion

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited in a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Response 3: Thank you for your opinion

Reviewer #2: Yes

Response 3: Thank you for your opinion

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Response 4: Thank you for your opinion

Reviewer #2: Yes

Response 4: Thank you for your opinion

5. Review Comments to the Author

Reviewer #1: 1) The text needs to be improved grammatically.

Response 5.1: According to reviewers’ suggestions, manuscript has been reviewed and edited by a university native English speaker.

Introduction

2) At the beginning of the Introduction, you are needed to add a brief introduction of various teaching strategies in motor learning. Then you need to enter the attentional focus as an important strategy. And then, please focus on different types of attentional focus (i.e., internal vs. external).

Response 5.2: We agree with the reviewer and have made corrections.

3) Introduction is too weak. The most recent theory on focus of attention is the OTPIAML theory. The authors have not explained this theory in the Introduction. In addition, the novelty of this study is not clear. If using a racquet sport is enough for novelty of this experiment. What is the difference between racquet and not-racquet sports? These issues need to be explained more clearly in the Introduction.

Response 5.3: We agree with the reviewer and we change this part of the introduction.

4) Why you chose low-skilled players and not absolutely novices?

Response 5.4: Thank you for your question. We chose low-skilled players after 30 hours of table tennis classes because we wanted to verify how to conduct skill improvement.

5) How the students were low-skilled? Were they at the beginning of the semester, mid of semester, or have already finished their courses?

Response 5.5: Thank you for your question. The students were at the finished of the semester after 30 hours of table tennis classes.

6) Is the info about BMI and etc. important?

Response 5.5: Thank you for your question. BMI and etc. are very important in a research investigation, but this issue was not the purpose of our work.

7) The info about sample size should be placed in the Participants.

Response 5.7: We agree with the reviewer and we change this part of the methods.

8) The most important issue in your study is attentional focus instructions. However, it is not clear how these instructions were provided and applied. The procedure of this study has not been included. How the participant performed the strokes? If a person from opposite side throws the ball? Or the participant took the ball in his/her hand? Please explain the procedure in all detail.

Response 5.8: We respectfully disagree with the reviewer. The procedure of this study has been included. The experimental groups followed a similar experimental design, with one difference – instruction concerning focus of attention only in the practice phase (no attentional focus instructions were given in pre-test or post-test). Participants of G1 group (IF) were instructed to “concentrate on the hand holding the paddle”, G2 group (EFP) received instruction “concentrate on the ball”, and G3 group (EFD) – “concentrate on targets marked on the tennis table”. The experimenter gave attentional focus reminders at the beginning of each block. On each test day, the participants performed 15-minute warm-up routine (running and physical exercises). A 30-second break was provided after each block. The post-test was administered immediately after the practice session. No attentional focus instructions or reminders were given in retention test to assess the relatively permanent effects of the instructions. The experiment was conducted on consecutive days in a sports hall and was performed on a standard-size tennis table approved by International Table Tennis Federation (ANDRO Magnum SC, Germany). Each of the participants used the same professional paddle with the following characteristics: blade (ANDRO "Inizio ALL", Germany) and rubbers (DONIC "Liga", 2.0 mm, Germany). Plastic table tennis balls (DONIC "Coach ** P40+ Cell-Free", Germany) were delivered to the participants by a table tennis robot (NEWGY Robo-Pong 1050, DONIC, Newgy Industries Inc., Tennessee, USA) which was positioned in the middle of the table, on the opposite side of the participant. The robot was programmed as follows: ball speed (level 13), frequency – the time between balls served (1.5 s; 40 balls/min), rotation type (topspin), the angle of the robot head (level 6), the ball placement on the table (for backhand strokes – left and right position: level 3). The assessment developed by Poolton et al. [26] was used to determine the accuracy of the strokes during the pre-test, post-test and retention tests.

9) In relation to the comment “8”, it should be said that table tennis is considered a very fast sport because the acceleration of the ball is very high. My most concern is how the participants in G2 could concentrate on a ball which moves very fast. I am really confused about choosing this sport to examine proximal and distal effects. It is hard to believe that the participants could focus only on distal distance in table tennis, as table tennis players focus mostly on balls, not on the table. May shooting a basketball could provide more accurate findings.

Response 9: We agree with the reviewer that table tennis is difficult and complex sport. Therefore the robot was programmed as follows: ball speed (level 13), frequency – the time between of balls served (1.5 s; 40 balls/min), rotation type (topspin), the angle of the robot head (level 6), the ball placement on the table (for backhand strokes – left and right position: level 3).

Results

10) The table 1 looks very simple. Please use a different table design.

Response 10: We agree with the reviewer and we change this part of the results.

11) You talked about so many statistical tests; however, they were not reported in the Results?

Response 11: We agree with the reviewer and we change these parts.

Discussion

12) It was assumed that the discussion held heavily on the differences between proximal and distal effects in attentional focus. However, based on the Discussion, it is not fully understood why proximal and distal effects are the same in this study. Please clarify your findings.

Response 12: We agree with the reviewer and we change this part of the discussion.

13) Finally, an important reason for the effectiveness of external focus of attention is “goal-action coupling”. However, you have not pointed it out in your discussion. Please use it as well as the OPTIMAL theory for discussing your results.

Response 13: We agree with the reviewer and we change this part of the discussion.

Reviewer #2: This is an appropriate paper I have no hesitation in recommending it. The statistics used are appropriate and the conclusion is consistent and sound. While not entirely novel, it could deserve dissemination across the scientific community. I am looking forward to your future success.

Response 5: Thank you for your opinion

Attachment

Submitted filename: RESPONSE TO REVIEWERS COMMENTS.docx

Click here for additional data file. (17.9KB, docx)

Decision Letter 1

Danica Janicijevic

18 Nov 2022

An external focus of attention enhances table tennis backhand stroke accuracy in low-skilled players

PONE-D-22-24485R1

Dear Dr. Tomasz Niznikowski,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Danica Janicijevic, Ph.D

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Thank you for your revision. You have addressed my questions and comments and I am satisfied with your revision.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Saeed Ghorbani

**********

Acceptance letter

Danica Janicijevic

23 Nov 2022

PONE-D-22-24485R1

An external focus of attention enhances table tennis backhand stroke accuracy in low-skilled players

Dear Dr. Niźnikowski:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Danica Janicijevic

Academic Editor

PLOS ONE

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