The effect of a high-pressure protocol on penalty shooting performance, psychological, and psychophysiological response in professional football: A mixed methods study

ABSTRACT The penalty kick in soccer is arguably one of the most highly visible and high-pressured sporting situations in the world. This study examined the effect of a high-pressure protocol on penalty shooting performance, and the associated psychological and psychophysiological responses to, and perceptions of that protocol. A sequential mixed-method research design was employed wherein the experimental condition consisted of a repeated-measures design with pressure as the within-participants factor (low-pressure, high-pressure). Quantitative data collection was complemented with a semi-structured interview. Twenty professional footballers took part. The Immediate Anxiety Measurement Scale (IAMS) and Pressure Likert-type scale were administered prior to both conditions. The NeXus-10 biofeedback system recorded players’ heart rate and respiration rate. Outfield players took five penalty kicks to four targets to the goal, under low and high-pressure. Pressure, cognitive anxiety, and respiration rate significantly increased in the high-pressure condition. After controlling for the level of pressure experienced in the high-pressure condition, bivariate variable error performance significantly increased (i.e., players were more variable in their grouping of shots under stress). Qualitative data indicated the 6-step high-pressure protocol predominantly evoked the distraction mechanism. This research provided first insight into the experiences of professional footballers to a simulated high-pressure penalty protocol.


Introduction
The penalty kick in soccer is arguably one of the most highly visible and high-pressured sporting situations in the world. More than 3.2 billion people viewed the FIFA 2014 World Cup and 1 billion watched the final (Fédération Internationale de Football Association [FIFA], 2015, para. 1). A quarter of games in the knockout stages at major tournaments are decided by a penalty shootout (Jordet et al., 2006), including two World Cup finals (i.e., 1994, 2006). The magnitude of such an occasion can have differential effects on performance depending on how one handles the situation. For example, the German National team had an overall success rate of 85% in six major penalty shootouts , conversely, England had only a 14% success rate from seven penalty shootouts (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)  . Anecdotal evidence from former England players suggests that poor performance in these situations may coincide with cognitive and somatic effects, including not being able to "think normally" (Owen, 2004, p. 100) or "breathe" correctly (Beckham, 2003, p. 275). Even under standardised laboratory conditions, the penalty kick has been shown to induce cognitive anxiety under high-pressure experimental manipulation (Wilson et al., 2009), and more generally, psychophysiological responses (e.g., respiration, Masaoka & Homma, 1997; heart rate, Navarro et al., 2013) are known to increase under stress.
When faced with a high-pressure situation (e.g., taking a penalty shot in a major tournament), players often perform sub-optimally (Jordet et al., 2007). This phenomenon has been termed choking under pressure and has been referred to as "performance decrements under pressure circumstances" (Baumeister, 1984, p. 610), although the operational definition of choking is subject to debate (Mesagno & Hill, 2013; review by Mesagno et al., 2015). Research has indicated that English players inadvertently adhere to the model of choking, specifically, they engage in sub-optimal self-regulation, such as high level of avoidance looking (e.g., turning their back on the goalkeeper after ball placement) and escapist behaviours (e.g., fastest response time from ball placement to execution), and poorer performance when executing a penalty in a shootout compared to more successful nations (Jordet, 2009).
Although there is now a large body of knowledge on choking in sport, and performance under stress more generally (reviews by Hanton et al., 2008;Mesagno et al., 2015), rather surprisingly, few studies have examined related effects on professional footballers in penalty kick situations using an experimental and/or mixed-method design. Existing research has focused on professional footballers during penalty shootouts, albeit in major tournaments, has been observational (e.g., Jordet et al., 2007) or retrospective qualitative (e.g., Jordet & Elferink-Gemser, 2012). In part, this may be attributed to the inherent difficulties researching this population (cf. Law, 2019).
The purpose of the present study was, therefore, to develop a high-pressure protocol that can be employed during a penalty shootout that leverages known theoretical explanations (i.e., distraction, Eysenck & Calvo, 1992; self-focus, Baumeister, 1984) and conditions (i.e., stressors and manipulations) that contribute to choking under pressure. One primary goal of this study was to assess the effect of this high-pressure protocol on psychological and psychophysiological response, and performance. A secondary goal was to examine the professional footballers' thoughts, feelings and experiences under low and high-pressure, and examine the extent to which they report effects that are consistent with known mechanisms (i.e., distraction and self-focus) articulated in current theories of choking.
Two influential theoretical explanations (i.e., distraction and self-focus) have evolved which explain the phenomenon of choking under pressure. Distraction theories (e.g., Eysenck & Calvo, 1992) suggest that as pressure increases, individuals become hypervigilant to threat that causes attention to divert to task-irrelevant internal and external stimuli (e.g., a penalty taker shifting their focus from taking the penalty towards the crowd noise). The cognitive component of anxiety, worry, can increase under such stressful conditions which often results in individuals investing additional resources to address the source of the stress (e.g., internal worry about missing). This increase in worry causes the capacity of working memory to be exceeded, leading to less efficient skill execution or performance impairment (Eysenck & Calvo, 1992;Eysenck et al., 2007). In contrast, self-focus theories (Baumeister, 1984;Beilock & Carr, 2001), also referred to as skill-focus (cf. Beilock & Carr, 2001;Englert & Oudejans, 2014;Oudejans et al., 2011) affirm that increased pressure to perform optimally causes the conscious mind of the athlete to take over and control the skill execution, termed conscious processing (Masters, 1992) or the athlete monitors the skill in a step-by-step manner, termed explicit monitoring (Beilock & Carr, 2001). Subsequently, well-learned, automated skills that are normally performed unconsciously are disrupted which results in impaired performance.
A number of variables (e.g., self-confidence) have been reported to influence and be a consequence of choking in athletes (Hill et al., 2010). Likewise, several causes for performance failure under pressure have been identified in the choking literature (e.g., unfamiliarity, event importance, Hill et al., 2010;audience/coach evaluation;Hill & Shaw, 2013; fear of negative evaluation, Mesagno et al., 2012;Hill et al., 2010). Consequently, such stressors (e.g., evaluation) have been used to induce pressure and/or anxiety in experimental studies. For example, Englert and Oudejans (2014) conducted research with semi-professional tennis players without directly manipulating attention. Anxiety was induced via evaluation, point scoring, performance comparison and feedback. Results exhibited that when anxious, distraction was the mediating factor affecting serving accuracy. These findings contradict a number of earlier studies that directly manipulated attention and found skillfocus to be the underlying mechanism (e.g., Beilock & Carr, 2001;Beilock et al., 2002;Jackson et al., 2006).
More specifically, several stressors have been reported by professional footballers when taking a penalty kick in a quarter-final UEFA European Championship (Jordet & Elferink-Gemser, 2012). In this insightful research, eight players were retrospectively questioned on their experiences during four phases of the penalty shoot-out (e.g., walk to the penalty mark, at the penalty mark). Players identified the break after extra time and waiting in the mid-circle as the most stressful phases. A number of stressors were reported across all four phases including, for example, waiting to take a penalty, the solitude of the walk up to the penalty spot, spectators' reactions and worry about goalkeeper's performance. The solitude of the walk was reported to be a lonely experience and cause overthinking. Conversely, spectators' reactions were reported to be an external distractor. Anecdotally, worry about the goalkeeper has also been reported by former international player, Steven Gerrard, who expressed concern on whether the Portuguese goalkeeper knew his preferred choice when executing a penalty in the World Cup (Gerrard, 2006, p. 464), and subsequently he missed his penalty. These findings indicate that similar stressors and manipulations should be considered as part of a high-pressure penalty design.
Expanding on stressors and manipulations further,  introduced a four-stage framework that coaches, researchers and practitioners might consider as a means to optimise psychological preparation for penalty taking. These areas were as follows: education, organisation, practice design (physical and mental), and practice structure. They suggested the mental practice design of pressure protocols and training should include activities and practices that manipulate players' anxiety, distraction, and perception of control. For instance, to include competition between players, invite audiences to watch (i.e., include an evaluative effect), both of which are known to cause a threat to an athlete's ego and contribute to choking (Hill et al., 2010;Hill & Shaw, 2013;Jordet, 2009). Although not football specific, Headrick et al. (2015) proposed that learning designs should consider the role of affect and interaction of emotion with cognitions, perceptions and actions. They suggested practitioners should create scenarios or vignettes that simulate the potential emotional and cognitive circumstances experienced in competition.
Using a 6-step protocol, the present experiment recreated pressure without directly manipulating attentional regulation. Rather than examine the independent and/or cumulative effect of multiple different stress manipulations, the focus of this study was to create a single pressure protocol that would simulate the dynamic nature of stress and emotions reported during a penalty shootout (Jordet & Elferink-Gemser, 2012). The current design was, in part, driven by the practicalities of working with professional football players (i.e., limited access, time restrictions, staff/player turnover; Gilmore et al., 2017). To elucidate, this 6-step protocol aimed to closely replicate real-world stressors (i.e., solitude of the walk, crowd noise, worry about the goalkeeper's performance, Jordet & Elferink-Gemser, 2012), and include known causes of choking reported in the literature (e.g., evaluation, direct competition). Put simply, such pressure manipulations under one single design are intended to replicate what a player may experience from the halfway mark to the penalty mark in a major tournament.
In view of research identified (e.g., Jordet et al., 2007;Masaoka & Homma, 1997;Navarro et al., 2013;Wilson et al., 2009), it was hypothesised the 6-step protocol would induce anxiety, pressure, and psychophysical response, and as a result, penalty performance and self-confidence would deteriorate. Given that the Immediate Anxiety Measurement Scale (Thomas et al., 2002) used in the current study measures the direction of anxiety, it was predicted anxiety would be interpreted as facilitative (Jones et al., 2004) under low-pressure and decline under high-pressure, and be interpreted as debilitative. Finally, independent predictor variables related to performance in low-and high-pressure conditions were determined.

Participants
Sixteen professional, male, outfield football players and four goalkeepers (M age = 16.94 years, SD = 0.68) were recruited as participants from a Category two Under-18 English League Academy. Institutional ethical approval was obtained prior to the study, and the players and professional football club provided written consent. Demographic data was collected (e.g., on age, competitive football experience, number of practice penalties taken in an average week). Participants had a mean of 10.12 (SD = 1.41) years competitive experience and reported executing a variable number of practice penalties in an average week 0 per week (n = 4); 1-5 per week (n= 10); 6-10 per week (n= 1); 31-36 per week (n = 1).

Apparatus
The experiment was conducted on synthetic turf at the professional club's training ground. Penalty kicks were executed to a full-size goal (7.32 x 2.44 m), 11 m from the goal line, using a size 5 mitre football inflated to 12.0 PSI. Penalty kicks were recorded from three different angles using Panasonic (HC-V500M) digital cameras. Camera 1 was placed behind the goal line (8 m 5 cm from the back of the goal line) in a central position (tripod height 1.85 m), camera 2 (subsequently used to measure ball speed) was positioned 6 m 10 cm to side of the goal from the post (tripod height 1.85 m), perpendicular to the trajectory of the ball, and camera 3 was placed 0.6 m to the side of penalty spot facing the goal (tripod height 0.5 m). A full-size (24 X 8 feet) Quickplay Pro-Standard target was positioned directly over the back of the goal line. The net was modified to include 4 targets (61 cm x 61 cm), one positioned in each corner (upper right, upper left, bottom right, bottom left) of the goal (cf. Wilson et al., 2009;Wood & Wilson, 2010a). Targets contained a centroid point (30.5 cm x 30.5 cm) depicted with a large orange peg. A fifth (centre) target was exclusively used for player familiarisation and warm-up. Participants were fitted with the NeXus-10 biofeedback system that recorded respiration (via a NX-RSP1A sensor) and heart rate (via an ECG NX1-EXG2-snap cable). Crowd noise was recorded using clips of previous penalty shoot outs from major football tournaments. In the high-pressure condition, noise reduction headphones (Phillips SHL38850NC) and an Apple iPod were attached to the player to permit introduction of crowd noise.

Perceived pressure
Preceding each pressure condition (low & high), participants rated the level of pressure they felt they were under on a 7-point pressure Likert-type scale anchored by 1 ("no pressure") and 7 ("extreme pressure") (Kinrade et al., 2010). Additionally, participants retrospectively rated the level of pressure perceived by each source of stress by using Kinrade et al's (2010) pressure Likert-type scale and responded to an altered question (e.g., " . . . take a moment to reflect on each aspect of the high-pressure condition and rate how much pressure you perceived you were under from each of the six stressors: 1 [no pressure] and 7 [extreme pressure]").

The Immediate Anxiety Measurement Scale (IAMS)
State anxiety and self-confidence was determined using the IAMS (Thomas et al., 2002). The scale includes three single items, one for each of cognitive anxiety (i.e., "I am cognitively anxious"), somatic anxiety (i.e., "I am somatically anxious"), and self-confidence (i.e., "I am confident"). Participants responded on a 7-point Likert-type scale anchored by 1 ("not at all") to 7 ("extremely"). In addition, participants were asked to determine how they interpreted each of the anxiety items by responding on a 7-point scale between −3 (debilitative to performance) and +3 (facilitative to performance). The intensity of selfconfidence on a scale from 1 to 7 was also measured.

Performance accuracy (ball destination)
The number of penalty shots scored, and on-target but saved were recorded for each player, and accuracy of each shot relative to the intended target was measured using Radial Error (RE) for two dimensions (i.e., the accuracy of the penalty shot in vertical [y] and horizontal [x] dimensions) and Bivariate Variable Error (BVE; i.e., each participant's mean variability of the shots from the centroid) (Hancock et al., 1995). Performance accuracy was analysed via frame-by-frame analysis of each penalty shot on a screen containing transparencies. Ball destination (x, y) was recorded in cm upon: i) contact with the Quickplay Pro-Standard target positioned on the back of the goal line; ii) first contact with the goalkeeper, and iii) the moment the ball came in contact with the back of the goal line (i.e., in the event the ball missed the goal). Following the recoding of the ball destination in centimetres, final (x, y) results were converted into metres and calculated using RE and BVE formulas.

Design
Given that G*Power (Faul et al., 2007) indicated a sample size of 27 would give sufficient power (0.80) to detect significant differences at the alpha level of 0.05 and that access to professional academy footballers was very difficult to obtain, a sequential mixed-method research (MMR) design was employed to offset weakness (e.g., low power), provide stronger inferences and allow for any shortcomings with either research paradigm by applying the strengths of each using triangulation (Bryman, 2006;Creswell et al., 2003), thus increasing validity. The experimental condition consisted of a repeated-measures design with pressure as the withinparticipants factor (low-pressure [baseline], high-pressure). Quantitative data collection was complemented with a semistructured interview immediately following the experimental phase. Participants took five penalty practice kicks to a fixed centre target (Binsch et al., 2010) without a goalkeeper present; this was to prevent any potential prior learning on both parts. Each player took a further two blocks of five penalty kicks under low and high-pressure with the presence of a goalkeeper. Five penalty kick trials in each block is also comparable to other studies containing low-threat and high-threat conditions (e.g., Wood & Wilson, 2010a).
Expanding on the existing research outlined, high-pressure was created by six means: (i) Each participant commenced the pressure test on the halfway line, returning to the halfway line after each penalty trial; (ii) Crowd noise, using an overly reactive crowd recorded from previous televised penalty shoot-outs was played via headphones throughout the duration of the penalty task; (iii) Ego-threat, by announcing to players they were in direct competition with each participant in the team and results would be ranked by the coach in order of success; (iv) Evaluation, by highlighting that the video recording of their performance would be evaluated by the coach post performance; v) Enforced targets, prior to each penalty trial participants were shown randomised targets to shoot to (i.e. players had no choice in shot decision); (vi) Goalkeeper informed about shot direction, by announcing to the player the researcher would inform the goalkeeper of the randomised direction and placement of the last two penalty shots. In reality, direct competition and coach evaluation were cover stories the coaching staff "played along with" until all data were collected. Previous studies have used expert evaluation and video recordings as cover stories with positive effect (e.g., Lam et al., 2009). In the low-pressure condition, players were instructed to execute penalties to a target of their choice from the penalty spot in the presence of the goalkeeper and researcher.
To substantiate quantitative findings, semi-structured interviews (Patton, 2002) were carried out by the first author and contained three main phases. Phase one introduced the study and collected demographic information about the participants. Phase two explored the players' thoughts and feelings experienced during both conditions, using two open-ended questions. Phase three elaborated upon quantitative findings, more specifically on highest perceived pressure ratings elicited from the retrospective use of the pressure Likert-type scale about the nature of the stressor. Probes in phase three varied from player to player (e.g., "I note that you rated "coach evaluation" in the pressure condition as a 7 ["extreme pressure"] -"what were you thinking in regard to this . . . ?").

Procedure
Participants attended a group education and experimental overview session wherein players were educated about all constructs on the IAMS (Thomas et al., 2002). Each player performed the tests at the Professional Football Academy in the presence of the first author and a goalkeeper. The NeXus-10, containing a respiration sensor and ECG was attached to each participant throughout low-and high-pressure conditions. Further instructions were provided immediately preceding the low and high-pressure condition (i.e., detailing pressure manipulations), followed by subsequent completion of the IAMS and pressure Likert-type scale before commencing each condition. Players informed the first author of their intended target preceding each penalty in the low-pressure condition. The player selected the target on a target card, and the primary researcher marked the target with an X in in front of the participant. This was to ensure performance accuracy could be measured against the intended or enforced targets in subsequent analysis. Both low and high-pressure conditions stimulated a keeper independent strategy (Van der Kamp, 2006). This was not alluded in order to discourage ironic effects (Bakker et al., 2006). Following completion of the 6-step highpressure protocol, each player completed the modified pressure Likert-type scale, and were interviewed.

Data analysis
Descriptive statistics were calculated for all subjective, physiological, and performance measures. RE and BVE performance were calculated in both conditions. First, paired-samples t-tests (including Cohen's d effect sizes, Cohen, 1988) were conducted on pressure ratings as a pressure manipulation check. Further paired t-tests were conducted on subjective and objective stress and self-confidence data. Effect sizes were calculated by subtracting the baseline means from the stress test means and dividing by the baseline standard deviation so that mean differences were expressed in baseline units. Second, correlation analyses were applied to quantify any relationships between measures of performance and stress measures (e.g., pressure rating) and to determine whether it was necessary to control for any associated effects in subsequent analyses of performance. Ultimately, two one-way repeated measures ANCOVAs were conducted to determine any differences between low and high-pressure conditions on RE and BVE. The pressure rating in the high-pressure test was used as a covariate.
Verbal data was analysed using both inductive and deductive methods of content analyses (see Patton, 2002). Interviews were transcribed verbatim and read several times for familiarisation. Inductive and deductive analysis was carried out by the first and second author independently. Validation for the general dimensions, higher-order themes and content was obtained through discussion. Quotations/ phrases were deductively analysed into general "thoughts" and "feelings" experienced in both low-pressure and highpressure conditions. Inductive themes that emerged from the data were clustered into similar independent points, and raw themes were generated. In the analysis of the highpressure thought data (i.e., players were questioned on their highest perceived pressure manipulations), players referred to specific elements of the high-pressure test in their responses, therefore, these were deductively analysed and categorised into the six high-pressure conditions, including accounts whereby players verbally reported low pressure from a stressor. Quotes representing a specific point were subsequently clustered with similar points, and raw themes were generated. Raw themes were subsequently categorised into higher-order and general dimensions (i.e., distraction, self-focus and emerging dimensions).

Pressure manipulation
Paired samples t-test revealed perceived pressure was significantly higher prior to the high-pressure condition (mean difference: 0.75 ± 1.06; t 15 = 2.82; p = < .013; 95% CI for difference: 1.32-0.18; d = 0.78) relative to the low-pressure condition (Table 1). Additionally, retrospective pressure ratings for each pressure manipulation 1 were significantly higher when compared to low-pressure pressure rating: crowd noise (mean difference:

Correlations
In the low-pressure condition, significant moderate, positive correlations were found between cognitive anxiety direction and ball speed, somatic anxiety direction and ball speed, indicating the higher the positive interpretation of cognitive and somatic anxiety direction the greater the shot speed (p < 0.05). No relationship was observed between measures of stress and performance. Under high-pressure, a significant moderate, positive correlation between pressure rating and BVE emerged, indicating the higher the pressure the greater the bivariate variable performance error (p < 0.05).

Penalty performance across conditions
Separate one-way (within-subject) repeated measures ANCOVA were conducted to examine the effect of pressure condition (i.e., low-pressure vs high-pressure) on performance (RE and BVE) while controlling for the covariate, high-pressure pressure rating (given the observed correlations between pressure rating and performance). There was a non-significant decrease in mean radial error performance, F(1,14) = 3.127; p = .099; η2 = 0.183 and a significant increase in BVE, F(1,14) = 4.845; p = .045; η2 = .257 between baseline and high-pressure conditions, when controlling for the pressure ratings in the highpressure test. These data suggest that players responded to stress by becoming minimally more accurate (Table 2) but significantly more variable in their grouping of shots. As stated earlier, RE and BVE assessed performance rather than scoring rate 2 (i.e., with the latter, a player could still score to a different target in error; therefore, it would not accurately assess the effect of pressure on performance). However, an interesting difference occurred in the scoring rate when the goalkeeper was informed of the shot placement of the fourth (3/16 shots scored) and fifth (11/16 shots scored) penalty shots in the highpressure condition. Given this observation and comments in the qualitative data (i.e., players reported increasing pace/ power/hitting the ball harder), further analysis indicated there Retrospective pressure rating means (and standard deviations) for each pressure manipulation can be seen in supplementary data, Table S1. 2 Scoring rate was not the main performance measure for the reasons stated; however, practitioners and coaches may be interested to note the overall scoring rate by professional footballers under these conditions. Further information can be found in supplemental data, Table S2.
was an increase in ball speed (

Qualitative data
Tables 3 and 5 exhibit general thoughts and feelings under high and low-pressure conditions. Tables 6 and 11 show specific thoughts related to each pressure manipulation. Given the restrictions on manuscript length, general dimensions and higher-order themes (italicised in text) are explicated in brief.

Player feelings experienced in low-pressure and high-pressure conditions
Under low-pressure (Table 3), emotions emerged as the single unitary general dimension, whereas under high-pressure emotions and coping emerged ( Table 4). The higher-order themes within emotion were consistent for both pressure conditions, these were as follows: Relaxed, Somatic anxiety and Excited. Under low-pressure, nine players reported feeling Relaxed (e.g., "I didn't really have any physical feelings") or feeling calm (n= 5). In comparison, under high pressure, there were fewer reports of no physical symptoms (n= 5), feeling calm (n = 1) and greater multi-faceted experiences of Somatic anxiety, with players reporting increased heart rate (n = 4) and multiple citations pertaining to increased tension, increased sweating, butterflies in the stomach and increased breathing (e.g., "I felt my heart rate was getting higher and I was breathing quite quickly and anxiety was coming in"). Only one participant reported Somatic anxiety under low-pressure (i.e., jelly legs and increased heart rate). The same symptoms were reported by the same player under high-pressure. It was apparent this player regularly experienced somatic anxiety (e.g., "I'm quite bad for that, like [sic] before games and that I have threw up before and stuff . . . "). In contrast, one player reported multiple situations where he felt Excited (i.e., when walking, placing the ball on the penalty spot). Regarding Coping, one player reported engaging in Adaptive and Maladaptive coping (i.e., taking a deep breath before taking the penalty and holding the breath when executing it).

Player thoughts under low-pressure
Under low-pressure, four general dimensions emerged, these were as follows: emotions, attentional focus, locus of control and skill (Table 5). Regarding emotions, nine players reported greater Self-confidence in their ability to score, with a further seven players reporting Self-confidence was due to internal locus of control (e.g., "I was confident that I was going to score, because I had my own choice at where I wanted to put the ball"). Regarding attentional focus, players reported Enhanced focus to the target (n= 9 citations in total). Related to this, several players articulated they had Low levels of distraction (n= 4; e.g., "I wasn't really thinking anything, I was just thinking I was quite comfortable in myself and I was confident in where I was going to put it"). Others conveyed they were not worried (n= 2) and not overthinking (n = 1). Although players reported higher Self-confidence and Enhanced focus under lowpressure, both Distraction and Skill-focus mechanisms emerged.  Felt calm (n = 5) Calm as keeper did not know where I was going (n = 1) Felt relaxed in body (n = 1) Legs felt loose (n = 1) Did not feel there was any pressure (n= 1) Felt fine after taking first penalty (n = 1)

Relaxed Emotions
Jelly legs (n = 1) Heart beating faster (n = 1) Somatic anxiety Positive emotion after scoring (n= 1) Excited Numbers in parentheses indicate the number of participants reporting the raw data theme Table 4. High-pressure: Player feelings.

Raw data themes
Higher order themes General dimensions No physical symptoms (n = 5) Felt relaxed (n = 2) Was calm (n= 1) Felt calm after penalty (n = 1)

Somatic anxiety
Positive excitement to perform under pressure (n = 1) Positive excitement when walking (n = 1) Positive excitement and nerves were switching when standing, walking and putting ball on spot (n = 1)

Excited
Took a big breath before (n = 1) Holding breath while taking penalty (n = 1)

Adaptive Maladaptive
Coping Numbers in parentheses indicate the number of participants reporting the raw data theme For example, one player reported being scared to miss prior to executing the first shot under low-pressure (e.g., "I would say I was . . . scared to miss"). Additionally, another player focused on the outcome (e.g., "just to try and obviously try and score as many goals as I could"), which has been reported as a distraction in previous choking research (e.g., Hill & Shaw, 2013). In contrast, one participant Skill-focused on movement and technical aspects under low-pressure (e.g., " . . . just strike through it really and just make sure you . . . don't open your body up too much so the ball goes the other way, or over hit it"). Concerning skill, one player reported it was difficult to hit the target.

Crowd noise
With reference to crowd noise (external stimuli), three general dimensions emerged. These were: attentional focus, emotions and match simulation (Table 6). Regarding attentional focus, Distraction (external and internal) was the most reported mechanism (n= 8 citations overall), with players indicating crowd noise was a direct distraction (n = 3), and it also affected decision-making (e.g., "it's a distraction, and you know it kind of almost makes you almost want to change your mind because you're not sure on where to put the ball"). Crowd noise subsequently caused internal distraction (n= 2; e.g., "just saying in my head saying you've got to score, you've got to score") or distracted players from their routine (n= 1). There were fewer reports of Enhanced focus overall (n = 1) compared to lowpressure (n= 9 citations overall, isn't it . . . "). In contrast, one player enjoyed the experience and reported Facilitative interpretation (e.g., "I liked the pressure from the crowd noise"). More generally, the crowd noise prompted players to reflect on experiences of match simulation and playing in front of a crowd.

Walk from the halfway
Two general dimensions emerged (Table 7), these were as follows: emotions and attentional focus. With regard to attentional focus, Distraction emerged as the underlying mechanism. Four players reported overthinking (e.g., " . . . the walking, because that's when you are proper thinking right"). Whereas Table 5. Low-pressure: Player thoughts.

Raw data themes
Higher-order themes General Dimensions Confident I would score (n= 9) I'm experienced at penalties (n = 1)

Self-confidence Emotions
Less pressure with target choice (n = 1) Low anxiety Confident when I had a target choice (n = 7) Shot placement Locus of control (Internal) Focused on target (n = 3) Knew where I was going to go (n= 2) I kept choosing same target (n = 1) Keep it away from GK and shoot to target (n= 1) I was focused (n = 1) Thinking what I was going to do (n = 1)

Enhanced focus Attentional focus
Not thinking too much or negatively (n= 4) Was not worried (n= 2) Made sure I did not over think penalty (n= 1)

Low level of distraction
Played mind games with GK (n = 2) Had doubts when I changed my mind with target (n = 1) Scared to miss (n = 1) Score as many as I could (n= 1)

Distraction
Focused on striking through ball (n = 1) Made sure I did not open body up too much (n= 1) Thinking hit it hard and with accuracy (n = 1)

Skill-focus
Difficult to hit exact target (n = 1)

Skill execution Skill
Numbers in parentheses indicate the number of participants reporting the raw data theme Match like Prefer to have a crowd (n = 1) Criticism when you do not score (n= 2) Praise when you score (n = 1) Presence of a crowd and pressure affects kicking (n= 1)

Reflection on presence of a crowd
Numbers in parentheses indicate the number of participants reporting the raw data theme Table 7. High-pressure: Effect of the walk-from halfway on player thoughts.

Raw data themes
Higher-order themes General dimensions Overthinking/had more time to think? (n = 4) Long walk gives the GK more confidence (n= 1) Worried I wouldn't score (n = 2) Thinking I have to score (n= 2) Felt more distracted (n = 1) Wanted to change mind (n = 2)

Distraction
Attentional Focus Emotions Nerves build up during walk (n = 2) Somatic anxiety Bored walking back and forth to halfway (n = 1)

Low arousal
Numbers in parentheses indicate the number of participants reporting the raw data theme other players reported wanting to change their mind (n = 2) and worry about missing (n = 2; e.g., "I think walking from the halfway line and the result of your penalty . . . if you miss and you think about it a lot more"). With regard to emotions, two players referred to their general experience of Somatic Anxiety during the walk. (e.g., it's just while you are walking there, you don't really know what to do, so you get . . . more nervous in the body as you are walking up"). In contrast, one player reported low arousal (i.e., being bored when walking back to the halfway line).

Enforced targets
Three general dimensions emerged concerning the effect of enforced targets, these were: emotion, attentional focus and skill (Table 8). Emotions emerged as the most cited general dimension. Eight players reported a decline in Self-confidence, this was related to shot autonomy and the experience of having to shoot to their non-preferred side (e.g., "I felt under pressure because I like to shoot to the left"). Players (n = 4) also reported Feeling pressured as a direct consequence of this (e.g., "I felt under pressure because . . . there's more chance of me missing"). Based on these statements, and in order to determine whether this may present as a confounding factor (i.e., whether players may have executed the vast majority of shots to preferred side under low-pressure relative to high-pressure), the number of penalty kicks to preferred side were assessed under both conditions. Data revealed players executed a similar number of shots to preferred side under low-pressure (shot choice; n= 50/80) and high-pressure (randomised shots; n = 45/80). Concerning attentional focus, both Distraction and Skill-Focus mechanisms emerged, with Distraction reported as the most prominent. Regarding skill-focus, one international player reported focusing on body shape before executing a penalty (e.g., "I was more worried about my body shape when shooting to my non-preferred side"). Three players revealed the skill of shooting to their non-preferred side was much more difficult.

Coach evaluation
Three general dimensions emerged, these were attentional focus, emotions and motivation (Table 9). Distraction emerged as the underlying mechanism. Players were concerned coaches may make selection decisions (n = 2; e.g., "it's . . . quite pressuring because I thought they are going to look back at this and they are going to see whose penalties are the best and they will . . . select a penalty taker from that . . . obviously, me being a striker as well, I want to be up there to take penalties this season"). Further distractions were related to worry about missing, coach scrutiny of technique or fear of being last in the team (e.g., "I was nervous, because you I was thinking I didn't want to be at the bottom"). In contrast, when questioned about other highest-pressure manipulation ratings, two players reported Low distraction from coach evaluation (e.g., "I wasn't really bothered about the coach evaluating or . . . being up against other players because . . . other players shouldn't really affect what I do . . . their score shouldn't affect mine . . . "). Concerning emotion, a number of players experienced Feeling Pressured (n = 3) and wanted to be more accurate (n = 1). For example, one player rated the coach evaluation (and direct competition ranking) as the main antecedents of pressure (e.g., "I think the coach, the coaches knowing and the ranking . . . puts more pressure on you [sic] because I wanted to be the best").

Ego-threat (i.e., direct competition and results ranked)
Two general dimensions emerged, these were: emotions and attentional focus (Table 10). Seven players were Feeling pressured to perform well, and there were multiple citations relating to distraction. The following player reported pressure and distraction (e.g., "there is a lot of competition within . . . the group to be the best so you want to score and with the competition, there was more pressure on making sure you do that, and I didn't want to be the worst").

Raw data themes
Higher-order themes General dimensions Not as confident shooting to non-preferred side (n= 8)

Selfconfidence Emotion
Non-preferred target makes you feel uncomfortable (n = 1)

Anxiety
Felt under more pressure (n= 4) Feeling pressured Anxiety in mind (n= 1) The selected target confused me (n= 1) Worried about result to non-preferred side (n = 1) Had to remember target (n = 1) Annoyed if I missed (n = 1)

Distraction Attentional Focus
Worried about body shape when shooting to non-preferred side (n = 1) Body shape not as good (n= 1)

Skill-focus
Made it harder (n = 3) Increased task difficulty Skill Numbers in parentheses indicate the number of participants reporting the raw data theme Table 9. High-pressure: Effect of coach evaluation on player thoughts.

Raw data themes
Higher-order themes General dimensions Worried coaches would make selection decisions (n = 2) Wanted to be selected to take penalties (n = 2) Worried what coaches would think (n = 1) Didn't want to be at the bottom (n = 1) Worried I would miss (n= 1) Worried coaches would scrutinise technical ability (n= 1) Wanted to be the best in the team (n = 1)

Distraction Attentional Focus
Not bothered about coach evaluation (n = 1) Thought coaches would not be bothered (n = 1)

Low distraction
Felt under pressure (n = 3) Wanted to be accurate (n = 1)

Feeling pressured
Emotions Nervous (n = 1) Somatic anxiety Good if you're top (n = 1) Coaches will see your confident if top (n = 1)

Ego-oriented Motivation
Numbers in parentheses indicate the number of participants reporting the raw data theme

Goalkeeper knowing the direction of the last two penalty shots in the stress test
Two general dimensions emerged, these were as follows: emotions and attentional focus (Table 11). Regarding attentional focus, Skill-focus and Distraction mechanisms emerged, with skill-focus the most cited. Related to skill-focus, several players reported either hitting the ball harder or increasing the pace and power on the shot (e.g., "it changes the way you [sic] are going to . . . take the penalty because he obviously knows where you are going to go, so you have to take it differently and hit it harder to make sure it reaches the net"). An international player at the club explained: "I needed to put more technique, more power on the shot because he knows where I am shooting, and if I just shoot it easy, he will just save it, so I focused on more power"). Expanding on emotion, players reported Feeling pressured (n = 4), with one player articulating how the combination of goalkeeper knowing the target and the pressure to score caused distraction and skill-focused attention (e.g., "because obviously, you're . . . thinking you're going to miss anyway, he already knows the direction that you're going in so it kind of adds more pressure . . . I tried to put a bit more power into my shots, so even if he went the right way he might not have a definite chance of saving it"). In contrast, other players reported they were less nervous (n= 2) and experienced less pressure (n = 2) when the goalkeeper knew the target (e.g., I was probably less nervous . . . when he knew where I was going because there was less pressure on me to score . . . so he should be able to save it).

Discussion
This study examined the effect of a 6-step high-pressure penalty protocol on performance and whether this evoked psychological and psychophysical stress. Additionally, professional footballers' thoughts, feelings and experiences were examined to determine the extent to which the reported effects were consistent with known mechanisms (i.e., distraction and skillfocus). In this study, players executed five penalty shots to a target centroid of their choice under low-pressure (i.e., in the presence of the first researcher and goalkeeper) and a further five penalty shots under high-pressure. In line with the hypothesis, the players' pressure rating significantly increased. This finding is corroborated in the qualitative data, specifically, feeling under pressure was reported in five of the 6-step pressure manipulations. The highest number of feeling pressured citations were reported with reference to direct competition (i.e., ego-threat) and provide further support that individual responsibility (i.e., closed skills) within a team sport cause a threat to the ego (Hill & Shaw, 2013). Accordingly, interventions to reduce the threat to the ego should be considered (see Jordet, 2010;cf. Wood et al., 2015). Cognitive anxiety intensity significantly increased under pressure. This finding was substantiated in the qualitative data. Attentional focus shifted from being predominantly task relevant (i.e., enhanced focused) under low-pressure to distraction based (e.g., worry, doubt, concern) under high-pressure (Eysenck et al., 2007). Distraction was reported by players with reference to every stressor within the 6-step protocol. The highest number of distractions were experienced during the walk from the halfway (e.g., more time to think, thinking I have to score) and are similar to thoughts experienced by professional footballers during the walk from the halfway in a major tournament (e.g., many thoughts, the ball must go in; Jordet & Elferink-Gemser, 2012). In response, players became significantly more variable (i.e., inconsistent) with their grouping of shots around the target centroid. Given that players' attentional resources were predominantly allocated to irrelevant stimuli owing to an increased reliance in the stimulus-driven attentional system (Eysenck et al., 2007) during the 6-step protocol, it can be assumed that overall, this caused increased shot inconsistency.
Although distraction was more widely reported, the goalkeeper knowing the shot placement of the last two penalty shots caused mixed emotions, with players reporting fear of failure, feeling more pressured, and interestingly, reduced anxiety in some. As stated earlier, Headrick et al. (2015) advocate that affective learning designs should embed emotions in situation-specific task constraints and consider the interaction with cognitions, perceptions and action. In this specific situation, cognitions changed with several players adopting a skill-focused attention. Regarding action and behaviour Feeling pressured Emotions Wanted to be the best (n = 4) Did not want to be the worst (n = 2) Thinking longer (n = 2)

Distraction Attentional Focus
Numbers in parentheses indicate the number of participants reporting the raw data theme Table 11. Low-pressure: Effect of the goal keeper knowing the direction of last two penalties on player thoughts.

Raw data themes
Higher-order themes General dimensions Needed to hit ball harder/put more power on the shot (n = 6) More technique required (n = 1) Traded technique for power (n = 1) Changes the way you take the penalty (n = 1)

Skill-focus Attentional Focus
Thinking I will miss (n = 2) Goalkeeper should save (n = 2) Tried to play mind games with goalkeeper (n = 1) Makes goalkeeper confident (n = 1) Distraction Under more pressure with GK knowing (n = 4) Got to be accurate (n = 3) Felt pressure to score (n = 1) More difficult to hit target (n = 1) Feeling pressured

Emotions
Got to trust own ability/skill level (n = 2) Selfconfidence Less nervous when goalkeeper knew target (n= 2) Less pressure to score (n= 2) If you miss you miss (n= 1 Not worried (n = 1)

Low anxiety
Felt nervous with GK knowing (n = 1) Somatic anxiety Numbers in parentheses indicate the number of participants reporting the raw data theme change, notable performance failure occurred on the first shot when the goalkeeper knew shot placement compared to the second consecutive shot. This dichotomy indicates the value of employing both single-shot research designs (cf.  and repeated practice. Speculating on this further, it could be argued that players choked on the first shot due to distraction and skill-focus, which has been reported in other studies (e.g., Hill et al., 2010) but changed shooting strategy on the consecutive shot (Wood & Wilson, 2010b) by implementing problem-focused coping (Jordet & Elferink-Gemser, 2012), and as reported in the qualitative data, applied more power and pace on the shot. Collectively, ball speed increased by 5.91 mph on the second consecutive shot, albeit was non-significant. This was also the fastest shot under highpressure and the second most accurate, and illustrates the importance of practicing under these conditions. Elaborating on this further, it was not the intended aim of this study to provide physical practice guidance (Wood & Wilson, 2011cf. Wood et al., 2015) but to focus on the mental design. However, several points can be forwarded in this regard. First, these findings lend support to Wood et al.'s (2015) suggestions, specifically, if players hit optimal areas of the goal, and at speed, the spatiotemporal constraints of the goalkeeper (Dicks et al., 2010) become evident to the player. Second, and related to practice, allowing players consecutive practice shots without practice education may encourage problem-focused coping. Both approaches can mitigate general worry related to the goalkeeper. Although players were significantly more variable with shots under pressure, and experienced notable shot failure on the fourth shot when the goalkeeper knew shot placement, mean RE decreased overall, albeit non-significantly, suggesting players responded to stress by becoming minimally more accurate. Future studies should consider repeated practice using the 6-step protocol. Practice with lower levels of anxiety has been shown to assist with performance maintenance, mitigate feelings of anxiety and prevent choking under higher levels of anxiety (Oudejans & Pijpers, 2009;Oudejans & Pijpers, 2010).
The prediction that somatic anxiety intensity would increase is refuted. Additionally, no significant difference emerged with somatic anxiety direction. The quantitative findings on somatic anxiety are akin to the qualitative results. Specifically, the highpressure training condition evoked several nuanced reports of somatic anxiety. Given that stress is a an ongoing transaction (i.e., appraisal) between the environmental demands and a person's resources (Lazarus, 1999), and that the penalty shootout is acknowledged to be a dynamic stress appraisal process (Jordet & Elferink-Gemser, 2012), it is conceivable that players reported lower somatic anxiety in response to the highpressure instructions on the halfway mark, yet experienced heightened somatic anxiety once the 6-step protocol commenced, as the qualitative data suggests. This finding lends credence to arguments put forward (e.g., Dunn, 1994) for researchers to adopt concurrent idiographic and nomothetic approaches rather than solely reporting on nomothetic data when accounting for individual differences and devising interventions within a sports team.
Congruent with previous research findings on the positive interpretation of anxiety by elite athletes (Jones et al., 1994;Jones & Swain, 1995), the direction of cognitive anxiety was interpreted as facilitative to performance. However, under high-pressure, positive interpretation remained, but significantly declined relative to low-pressure and provides further speculative insight as to why BVE may have significantly increased. Given that cognitive intensity was reported to be significantly higher immediately following the high-pressure instructions, it could be argued that players' attentional resources were predominantly allocated to irrelevant stimuli (i.e., they were distracted by the forthcoming pressure manipulations) owing to an increased reliance in the stimulus-driven attentional system (Eysenck et al., 2007). Given this system is automatic and unconsciously operated, then it can be assumed that overall, the ability to reflect on these interpretations was reduced, and therefore, they did not interpret their anxiety as debilitative.
In line with predictions, self-confidence significantly decreased under pressure and is corroborated in the qualitative data. Players cited greater self-confidence in their ability to score, and greater self-confidence when they had shot autonomy under low-pressure compared to high-pressure. These findings differ from previous experimental studies that found no significant difference in self-confidence in elite football players who executed penalty shots to self and externally controlled targets (Navia et al., 2019). It is worth noting that selfconfidence data were collected post experiment in the latter study; however, in the present study, data were collected immediately following the 6-step protocol pressure instructions and corroborated in the qualitative data. Reductions in self-confidence have been reported as a consequence of error rate and self-criticism (Hill & Shaw, 2013) and also correspond with increased BVE under high pressure. To improve selfconfidence, these findings support the notion that penalty practice design should focus on target-specific practice to the four targets (Wood & Wilson, 2011cf. Wood et al., 2015), and include expert technical guidance (i.e., using a range of expert penalty takers who are able to provide technical guidance on shooting to various targets).
It was hypothesised that respiration rate would increase under pressure, this was supported. Despite the significant increase in respiration in the current study, caution should be noted. What is not explicitly clear is whether respiration rate significantly increased due to stress response or due to the walk from the halfway. To clarify, in the low-pressure condition, players were not required to walk from the halfway, this only occurred under high-pressure. Due to time restrictions, it was not possible to obtain average respiration rate during a simulated walk from the halfway to the penalty spot without the high-pressure protocol; this would have enabled further analysis to determine whether walking or stress evoked the significant increase. This should be addressed in future studies. It was predicted that heart rate would significantly increase under pressure, interestingly, this was refuted and is not in line with previous research. (Oudejans & Pijpers, 2010) given that pressure and cognitive anxiety were significantly higher under high-pressure. A possible explanation for elevated heart rate is that penalty shots were taken in quicker succession under low-pressure relative to high-pressure condition with the walk. Further, it is plausible that players experienced autonomic physiological arousal, as reflected by heart rate at the start of the experiment but did not interpret their anxiety as high under low-pressure. This warrants further investigation.
It is not within the scope of this study to discuss the conceptual differences between choking and under performance (Mesagno & Hill, 2013). That said, it is clear players experienced changes in cognitions and emotions which are consistent with mechanisms of choking. Overall, the present findings strengthen the extant literature that choking is caused by distraction (e.g., Englert & Oudejans, 2014;Gucciardi et al., 2010;Hill et al., 2010;Hill & Shaw, 2013;Oudejans et al., 2011). However, specific stressors (e.g., worry related to, and/or the goalkeeper knowing shot placement) caused distraction alongside skill-focus. The interaction of both mechanisms is known to cause choking in elite golfers; similarly, distraction was the most reported mechanism overall (Hill et al., 2010). Accordingly, players should be profiled and provided specific interventions to accommodate the changing mechanisms reported. Distraction-based interventions (e.g., pre-performance routines and deep breathing) to prevent attention being diverted from task-relevant to taskirrelevant cues should be explored (see review by Gröpel & Mesagno, 2019) alongside the 6-step protocol. For example, deep breathing has been used to improve kicking performance in Australian rules football (Mesagno & Mullane-Grant, 2010), mitigate pre-competition somatic sickness (Ellis, 2016), improve attention, and lower negative affect (e.g., fear) in the general population (Ma et al., 2017).
The findings from the current study have implications for coaches and practitioners. First, the dynamic changes in players' emotions and cognitions provide insight on the benefit of employing a single pressure design that is representative of the real-world task. Specifically, players face evaluation, direct competition, auditory stimulus from the crowd and solitude during the walk (Jordet & Elferink-Gemser, 2012). Embedding emotions in situation-specific tasks (Headrick et al., 2015) is imperative. For example, goalkeepers are known to research opposing players' preferred shot choice; therefore, and as suggested earlier, the inclusion of the goalkeeper knowing the target may alleviate emotional worry related to the goalkeeper's performance (Gerrard, 2006) and promote positive action and/or problem-focused coping (Jordet & Elferink-Gemser, 2012). Valuable information about this stressor was obtained from the aforementioned research and autobiography. This highlights the value of interviewing athletes to identify situation-specific stressors (Headrick et al., 2015). The 6-step protocol could be used alongside long-term baseline assessments, interviews, profiles and interventions.
Although the inclusion of enforced targets (i.e., no shot autonomy) under high-pressure may differ from the real-world task, this stressor does have potential interactions with the goalkeeper knowing the preferred target. For example, the penalty shootout between England and Holland Under-21s in 2007 resulted in 32-penalty shots being taken, with some players having to execute two penalty shots in the shootout (and missing the second shot). In this instance, players may experience cognitive worry in relation to shot choice and the goalkeeper. Football is a highpressured environment (cf. Gilmore et al., 2017), often with time constraints, particularly at international level. In the absence of sufficient time to employ specific coping strategies for various phases of the penalty kick (Jordet & Elferink-Gemser, 2012), employing enforced targets alongside physical practice education (Wood & Wilson, 2011cf. Wood et al., 2015) may be an effective practice. Additionally, it is also imperative that players practice with shot autonomy under high-pressure (i.e., using the previous five steps). Finally, regardless of whether respiration rate significantly increased due to stress or the walk from the halfway, players should practice under the same psychological and physiological demands (cf. . In addition to the limitations identified earlier, caution should be applied when generalising the findings to senior international players. That said, the professional academy players experienced similar thoughts and feelings to those reported by senior professional players in a major tournament penalty shootout (Jordet & Elferink-Gemser, 2012). Access issues and time restrictions with this population prevented a higher number of penalty trials; however, the number of penalty trials taken in the current study is equal to those taken in previous low and high-threat conditions (e.g., Wood & Wilson, 2010a). Additionally, a mixed-methodology was employed to increase validity. Finally, players signed a consent form that stipulated they were not to inform other players about the low-and high-pressure condition, there is the possibility that players may have shared this information. However, the pressure manipulations and qualitative accounts of pressure still increased under high pressure.
In conclusion, this research provided first insight into the experiences of professional footballers to a simulated highpressure penalty protocol. Quantitative results indicated an increase in pressure, cognitive anxiety, respiration rate, BVE and reduction in self-confidence under high-pressure. The qualitative data indicated the six-step high-pressure protocol predominantly evoked the distraction mechanism. A closer examination revealed specific stressors can cause distraction and skill-focus. The data provide insight for applied professionals and coaches on the potential value of training under the 6-step protocol conditions.