Upon approval from the university research ethics board, two researchers joined a rock climbing club of a well-known university in East China from September 2018 to January 2019. During rock climbing in this club, researchers established social relationships with other club members and recruited them as interviewees through convenience and purposive sampling. Participants were included according to the following criteria: (a) has rock climbing experience for 1 year or more; (b) rock climbing twice a week or more; (c) rock climbing for 1 hour or more at a time. The determination of the number of interviews was based on the principle of saturation of the information provided. At the same time of collecting interview data, researchers conducted data analysis. Until the coding results of the latter interview data were similar to the previous results, and no new prominent themes appeared, then the invitation and recruitment of participants were stopped. Finally, with consent, a total of 15 rock climbers were interviewed (see Figure 1). Among these participants, 9 were male rock climbers and 6 were female rock climbers, with an average age of 23.1 years old (SD = 1.61, range = 21-27). Take the level of bouldering as an example, with 9 participants below V3 and 6 participants above V4. Also, all participants had a rock climbing experience of one year or more and a rock climbing frequency of two or more times a week. Table 1.

This study adopted relativism ontology (reality is pluralistic, created, and depends on thought) and constructivism epistemology (knowledge is constructed and subjective) as philosophical underpinnings.

Semi-structured interviews are usually used in qualitative research. The advantage of a semi-structured interview is that it can give both the interviewer and the interviewee a certain degree of freedom to jointly discuss the central issues of research29. The researchers conducted semi-structured interviews with participants to guide them to think, understand, and accurately express their psychology and behavior, to collect complete information of participants. Moreover, the researchers encouraged participants to focus on the dialogues of self-expression30. Before the interviews, according to the purpose of this study and relevant literature, researchers developed the semi-structured interview guide in advance. The interview questions mainly include: (1) Have you ever experienced frustration in rock climbing? (2) For you, what is the cause of frustration? (3) How do you regulate yourself to deal with frustration?

The researchers conducted two rounds of semi-structured interviews from January 2019 to March 2019. The first round of interviews collected the participants' basic information at first, such as grade, age, current level, how often per week. Next, according to the interview guide, the researchers mainly understood participants' frustration experience and self-regulation. During interviews, the interview guide was supplemented and adjusted based on their answers. The interviews lasted an average of 40 minutes (SD = 6.92), mostly in the cafe of the university. The researchers informed participants about the purpose of the interview and guaranteed the anonymity of the interview. After obtaining the consent of participants, interviews were done by audio-record. All potential identification information (e.g., name and major) was modified or deleted from the transcripts to protect the confidentiality of the participants. After the initial coding of the transcripts from the first round of interviews, the researchers found some information omissions, and further understanding of some issues was needed from participants. As a result, the second round of online voice interviews was conducted to supplement interview information.

In qualitative research, data collection and analysis are generally carried out simultaneously. At the end of each interview, the researchers quickly turned the recording into a transcript and summarized key statements of the rock climber. Given the large amount of data generated in the interview process, this study used NVivo11.0, a qualitative analysis software, to store and analyze the data. According to the thematic analysis steps outlined by Braun and Clarke (2006), the researchers conducted an inductively thematic analysis of the transcripts31. Thematic analysis steps mainly consist of familiarity data, generating initial codes, creating themes, and reviewing themes.

First, the researchers read the interview transcripts many times to get familiar with the content and deeply understand the participants. Then, six transcripts were initially coded for ideas and experiences of the rock climbers. Nine additional participants who met the criteria were interviewed, and their transcripts were analyzed using initial codes generated by the first six transcripts, and allowing for the identification of new prominent codes at the same time. After all the transcripts were analyzed, the researchers and experts discussed and reviewed each code to ensure that they had sufficient narrative support. Next, the researchers classified the codes, identified common themes among several codes, and created a list of themes. At last, the list of themes was reviewed by the researchers and experts, to ensure that each theme summarized the contained codes and had clear differences from other themes. Codes and themes were constantly reviewed by the researchers, and they were refined, merged, separated, or discard until all researchers believed that the current themes list accurately summarized and represented data.

According to the philosophical underpinnings of this study, the quality evaluative criteria proposed by Smith and Caddick (2012) were used: impact, coherence, credibility, and transparency32. Impact was realized through identifying themes that have implications on future studies, establishing self-regulatory mechanisms for rock climbing frustration, and providing suggestions for rock climbers to self-regulate frustration. Coherence was attained by taking every participant's data into account through thematic analysis and ensuring that the identified themes were supported by sufficient data. Credibility was ensured by the researchers joining the rock climbing club before semi-structured interviews, and socializing with potential participants to build trust relationships in advance. These made the participants willing to share the real frustration experiences in the interviews. Moreover, semi-structured interviews had a certain degree of freedom and flexibility, enabled the researchers to follow up on participants’ ideas which were not necessarily in the interview guide. Also, member reflections were used to provide participants with the opportunity to reflect and discuss credibility. They checked interview transcripts and research results to ensure accuracy and empathy with their experiences33. The researchers reviewed and revised the themes according to the comments and suggestions of participants. Transparency was kept throughout the process. Several researchers worked together to develop the interview guide, analyze data, and create themes. Senior authors questioned and challenged the process of data collection, theme creation, and interpretation, and encouraged further in-depth thinking and refinement of the theme list.

Almost all participants said that they often encountered frustration in rock climbing, and task comparison and social comparison were the two main causes of frustration.

Some rock climbers experienced frustration simply because of task comparison. They were blocked from completing a task (e.g., a route or an action) or had no progress for a long time. For example, Tian(M) described his frustration experience, "When I've been rock climbing for half a year, there was a very difficult route, I couldn't finish it all the time. I doubted myself at that time and felt depressed." Hu (M) felt similar to Tian(M), he said, "I feel frustrated when I can’t climb up some routes." Huang (F) was anxious about her progress, she said, "I feel frustrated when I can't overcome a certain level. Mostly because there has been no progress for a long time."

Some rock climbers experienced frustration simply because of social comparison. For the same task (e.g., a route), they would feel frustrated if others earlier finished or made more progress than themselves. For instance, Shen(M) said, "I don't feel too frustrated every time I can't climb over. But frustration usually occurs when I compare myself with others, that is, I get frustrated when others have similar conditions in all aspects but climb much better than me." Ge (F) also felt a strong sense of frustration when comparing herself with others, she said, "If there is a climbing holds that everyone passes easily, but somehow I can't pass, I will feel frustrated, get desperate and want to cry. I begin to doubt myself and sometimes have to admit that rock climbing requires talent. " Zhu (M) thought that being competitive would lead to frustration. Exemplifying this, he said, "if others can pass a certain route, but I can't, I will think that my training today isn’t effective. I feel weaker than before and feel like not making any progress."

Other rock climbers believed that both task comparison and social comparison led to frustration. For example, Shi (F) said, "If the route being climbed now is always unable to climb up, or if I am falling behind with others, I will feel frustrated." Similarly, Fang (F) described her feelings about two kinds of frustration, "At times, there is a route or climbing holds that I've been trying for one night even a week or two, but I still can't do it, it frustrates me. Then I see that everyone else can do it, thus I will feel very annoyed and frustrated again."

All the rock climbers recalled their self-regulation in dealing with rock climbing frustration. They were asked to describe what would be effective self-regulation strategies. For task comparative frustration, two themes were emerged: focusing on tasks and habitual reflection.

Confronted with task comparative frustration, rock climbers regulated their attention to focus on the tasks that frustrated them and increased their efforts to complete the tasks. Even in adverse situations (i.e. under the pressure and blow of task failure), they still maintained a high level of achievement motivation and tried their best to complete tasks. Wang (M) introduced his frustration self-regulatory experience in climbing a roof route, "Climbing to the roof is different from climbing on the wall. There’s great psychological pressure, and falling from the roof can give you a special psychological blow. So it requires a lot of perseverance to overcome the roof route. At that time, I always fell from the roof and suffered great psychological shocks, but I never gave up and kept climbing. It takes me more than one year to climb up the roof route." Hong (M) also regulated himself by focusing on his task during frustration, he said, "Last year when I was bouldering, I felt that my ability had not improved for some time. I was very depressed at that time. Then I focused on that route, kept climbing and practicing, so my ability was raised a little."

Because of frustration, some rock climbers even greatly enhanced their desire to complete tasks or achieve goals. For instance, Xu (M) thought that he would be motivated by his frustration, he explained, "I would be very upset if I couldn't complete something. I like to do my best until I achieve it. For example, if there’s a route I can’t climb up, I will keep climbing all the time, even for a month. I won’t stop until I climb to the top."

It was important self-regulation when facing task comparative frustration. Rock climbers drove themselves to gradually form a habit of self-reflection, often thinking about the reasons for their failures and solutions to the problems. For example, Zhang (M) believed that timely reflection when encountering frustration helps to achieve the goal, he said, "If I have been climbing this route for so long, but still failed, I won’t be discouraged. After climbing, I will consider how to overcome, how to solve, how to climb up. I was used to reflecting on myself before I participated in rock climbing, so rock climbing is so suitable for me." Likewise, Tian (M) thought that he was influenced by rock climbing to reflect on why he failed in a route, he explained, "After climbing for a long time, I sometimes reflect on myself because of the influence of rock climbing. I wonder why I can't finish the route. Maybe my foot movement is not in place, or there is a foothold that I did not notice, or I’m not proficient in climbing skills. I need to reflect on how I climbed just now, and how to solve such problems if I encounter them later.”

Notably, based on a three-year climbing experience, Wang (M) concluded that most high-level rock climbers, regardless of whether they are in frustration or not, have the habit of reflection. He said, "Not every climber gets used to reflection, but you must be like this if you want to climb well. Most of the masters I've met usually watch silently, think quietly, and then climb quietly. "

For social comparative frustration, two themes were identified: emotion regulation and changing goal orientation.

When rock climbers met with social comparative frustration, they often experienced very negative emotions and feelings, such as "ashamed", "anxious", "depressed", "sad", "angry" and "incompetent". In general, emotion regulation was the first method to deal with social comparative frustration, which aimed to reduce the negative reaction caused by frustration and protect self-esteem. For example, Liu (F) found out her achievements through downward comparison to improve her mood, she shared, "I feel I’m the worst with these people at ordinary times. But whenever new members joined, I think that when I just joined, I climbed as badly as they did, and I've improved after a year of training, so I'll be in a better mood." Xu (M) said that he consciously controlled his emotions by distraction. Illustrating this, he said, "I will get irritated when I can't climb up all the time but others can. Then, I will gradually control my emotions, take a rest, play with my cell phone, or talk to others." Shen (M) reappraised the frustration and soothed himself when he felt depressed due to social comparison, he explained, "I will be a little sad, but I will comfort myself that I may not be as strong as my friend, so it is reasonable for him to climb up so easily. I will climb up that route if I practice more."

Moreover, rock climbers' emotional regulation ability gradually improved with rock climbing more time. When faced with similar frustration again, they were less likely to produce negative emotions. For instance, Hu (M) said, "If encounter situation like this again, I will not feel so bad."

In the field of sports and exercise, Nicholls (1984) generally distinguishes the goal perspective into task orientation and ego orientation34 People with task orientation focus on personal progress and their success comes from mastering skills. In contrast, people with ego orientation pay more attention to success from surpassing others^35,36.For social comparative frustration, rock climbers changed their goal orientation. Specifically, they changed from ego orientation to task orientation, and from pursuing conquer others to conquer themselves.Zhu (M) thought that after climbing for some time, his point of view changed, he said, "I think my competitive spirit has weakened to a certain degree, from comparing with others before to comparing with myself now." Likewise, Li (F) said that her goals in rock climbing had changed: "Before, I thought that I could do what other climbers could do, but now it’s different. As long as I make progress, that's fine with me."

After climbing for some time, rock climbers' idea of winning the competition would weaken. Zhang (M) indicated that he no longer pursued to surpass others in rock climbing, he shared, "Now I rock climbing is to release stress and have fun, and I don't care about whether I climb better than others." Liu (F) gradually stopped paying attention to achievements and results, and she enjoyed the climbing process more. She admitted, "At first, I was a little competitive, but later it seemed to become less with climbing more. As long as I try my best, it doesn't matter what the result is."

Rock climbers gradually realized that rock climbing was a self-challenging sport. Tian (M) stated, "I found later that rock climbing is a process of constantly challenging yourself. The difficulty of each route is there. If you have strength, you can complete this route. If you don't have strength, you can't. This is a process of competing with yourself." Similarly, Hong (M) analyzed why he likes rock climbing so much, "Rock climbing lets you challenge yourself, there is no need to compare with other people's level."