Mental Toughness Research

Transcription

1 Mental Toughness Research Mental toughness and stress resilience in adolescents Markus Gerber 1, Nadeem Kalak 2, Sakari Lemola 3, Peter J. Clough 4, Uwe Pühse 1, Edith Holsboer-Trachsler 2, Serge Brand 2 1 Institute of Exercise and Health Sciences, University of Basel, Switzerland 2 Psychiatric Hospital of the University of Basel, Depression and Sleep Research Unit, Switzerland 3 Department of Psychology, University of Basel, Switzerland 4 Department of Psychology, University of Hull, United Kingdom Address for correspondence: Markus Gerber, PhD Institute of Exercise and Health Sciences, University of Basel, Switzerland, St. Jakobsturm, Birsstrasse 320B, CH-4052 Basel, Phone : , Fax : , markus.gerber@unibas.ch

2 Mentally tough adolescents are more resilient against stress Abstract Mental toughness has been explored predominantly from an inside sport perspective. Nevertheless, it is difficult to conceive mental toughness as only applicable to athletes. This study examines whether the factor structure of the Mental Toughness Questionnaire (MTQ) can be replicated by means of a confirmatory factor analysis in a sample of high school students. Furthermore, this study tests whether mentally tough participants are more resilient against stress. A total of 284 high school students (99 males, 185 females) aged M = 18.3 years (SD = 4.17) filled in the MTQ, Perceived Stress Scale and Beck Depression Inventory. The findings supported the internal and external construct validity and reliability of the MTQ, although some items had unsatisfactory factor loadings. Most importantly, the findings showed that high mental toughness mitigates depressive symptoms if participants perceive high stress. More research is needed to understand whether mental toughness can be improved by means of exercise training and whether increases in mental toughness explain how exercise contributes to the reduction of depressive symptoms. Keywords: Depressive symptoms, stress-buffer, mental toughness Introduction During the past ten years, mental toughness research has strongly focused on elite athletes (Jones, Hanton & Connaughton, 2007). Clough, Earle and Sewell (2002) noted that in 75 percent of contacts with athletes and coaches, the development of mental toughness was mentioned as a central theme. Nevertheless, it is difficult to regard mental toughness as only applicable to athletes as many other competitive and pressured environments exist beyond sport (Crust, 2008). Therefore, the main purpose of this article was to find out how mentally tough individuals cope with pressure and adversity outside sport. Definitions of mental toughness based on qualitative research Mental toughness has long been regarded as a not well understood phenomenon. For many years, the literature regarding mental toughness was characterized by a lack of scientific rigor and conceptual clarity (Crust, 2008; Jones, Hanton & Connaughton, 2002). The term mental toughness was popularized by Loehr in the mid 1980es to describe athletes who are able to maintain an ideal performance state consistently throughout the heat of competition. Across interviews with hundreds of athletes, Loehr found surprising similarities in athletes experiences leading to peak performance. Loehr (1986) conceived mental toughness as being able to perform consistently toward the upper range of one s talent and skill, regardless of competitive circumstances. Nevertheless, Loehr s definition has been criticized because it was solely based on practical experience, anecdotal stories, and previous how-to publications (Mack & Ragan, 2008). Due to the lacking scientific precision of his definition, almost every positive psychological skill fell under the umbrella of mental toughness (Crust, 2008; Jones et al., 2002). The scientific investigation of mental toughness has started about ten years ago. Jones et al. (2002) provided useful clarity by presenting a rigorous definition based on interviews with ten international elite and super elite athletes from various sports. Jones et 1

3 al. (2002) identified twelve microcomponents of mental toughness, comprising six general areas including self-belief, desire and motivation, performance-related focus, addressing pressure or anxiety, lifestyle-related focus, and addressing pain or hardship. Mental toughness was defined as having a natural or developed psychological edge that enables an athlete to cope consistently better with the pressures and demands of the sport during training, competition and in his or her lifestyle. Jones et al. s (2002) definition and conceptualization of mental toughness was supported in later qualitative research with elite and subelite athletes (e.g. Jones et al., 2007; Thelwell, Weston & Greenless, 2005). Taken together, qualitative research provided rich, descriptive interpretations of mental toughness and demonstrated the multidimensional nature of the concept. Today, general definitional consensus exists in the sense that researchers agree that mental toughness describes an individual s ability to cope with the stress and anxiety associated with competitive and stressful situations. Moreover, a certain number of key components have been consistently highlighted across studies including powerful self-beliefs, commitment, self-motivation, thriving on competition and challenges, retaining psychological control under pressure, resilience, perseverance, and focus (Crust, 2008; Mack & Ragan, 2008). Despite the fact that the similarities across qualitative studies support the trustworthiness of the data, qualitative research has been criticized because of the prevailing assumption that elite athletes would be automatically mentally tough (Crust, 2008; Crust & Azadi, 2010). Following Thelwell et al. (2005) this notion is problematic as one could infer that any individual involved in elite sports would be knowledgeable about mental toughness. Another point of criticism is the lack of theoretical background prevailing in studies using a qualitative approach towards defining mental toughness (Middleton, Marsh, Martin, Riches & Perry, 2006). A theory-driven definition of mental toughness Drawing on interviews with athletes, coaches and sport psychologists, Clough et al. (2002) presented a theory-driven model of mental toughness. Following Clough et al. (2002), mental toughness is closely related to hardiness (Kobasa, 1979), a concept firmly rooted in health psychology. Hardiness represents a trait-like characteristic that influences the way people perceive situations and react on stressful circumstances. In line with this, past research has shown that hardy individuals are more effective in coping with stress and that hardiness protects against stress-induced health symptoms (see Maddi, 2004). Kobasa (1979) identified three key components of hardiness including control (tendency to feel and act as if one is influential in the face of the varied contingencies of life), commitment (tendency to involve oneself in, rather than experience alienation from whatever one is doing, or encounters), and challenge (belief that change, rather than stability, is normal in life and that the anticipation of changes are interesting incentives to growth rather than threats to security). While control helps individuals make appropriate decisions about how to cope with potentially stressful situations, commitment keeps people proactive instead of accepting passively a given situation. Finally, challenge supports people to develop and grow, rather than safeguarding what the person already has (cp. Clough et al., 2002). In order to more fully represent the sport specific character of mental toughness, Clough et al. (2002) added confidence as a fourth factor (resulting in the 4Cs model of mental toughness). Specifically, mental toughness was described as a person s tendency to 2

4 be sociable and outgoing. Mentally tough individuals are able to remain calm and relaxed when facing stress, are competitive throughout various situations and generally experience less anxiety than others. Besides, mentally tough individuals are characterized by a high sense of self-belief and an unshakable faith to be able to control their own destiny. Hence, these individuals normally remain relatively unaffected by competition or adversity (Clough et al., 2002). Quantitative measures of mental toughness Researchers have only recently started to develop comprehensive measures of mental toughness. At the present point in time, at least three general questionnaires exist that are not only applicable to a specific sport. Nevertheless, the Psychological Performance Inventory (PPI: Loehr, 1986) and the Mental Toughness Inventory (MTI: Middleton et al., 2006) are not suited for the use outside sport due to their sport-specific item formulations. In contrast, the Mental Toughness Questionnaire (MTQ: Clough et al., 2002) has a broader applicability. Drawing on Kobasa s hardiness concept, the MTQ connects established and robust psychological theory with sport-specific elements and is equally useful for general psychologists, coaches and applied sport psychologists. The 48 items can be summed up to built an overall score. Additionally, the scores for eight subscales can be calculated (total control, control emotion, control life, commitment, challenge, total confidence, confidence abilities, confidence interpersonal). Moreover, an 18-item short form exists. Principal components analysis with varimax rotation was used to established dimensionality of the MTQ with a large sample of athletes from a variety of sports (Clough et al., 2002). In addition, Horsburgh et al. (2009) performed both exploratory and confirmatory factor analyses and provided support for the original factor structure. Moreover, several studies showed that the reliability ( = ) of the overall toughness indices and the testretest correlations (r >.90) of the MTQ subscales are high (Clough et al., 2002; Crust & Azadi, 2010; Kaiseler, Polman & Nicholls, 2009; Nicholls, Polman, Levy & Backhouse, 2009). Compared to the total indices, the Cronbach s alpha values of the MTQ subscales are lower, but still acceptable (Nicholls et al., 2009). Kaiseler et al. (2009) indicated that the internal consistency of the emotional control subscale was low, but could be substantially improved after deleting items 26 and 34. Additionally, these researchers showed that the long and short forms are strongly correlated and that the MTQ subscales are highly associated with the overall toughness indices. Last, moderate correlations were found between the various MTQ subscales. With regard to external construct validity, moderate to high correlations existed between the MTQ48 overall index and other psychological constructs such as optimism, selfimage, life satisfaction, and self-efficacy (Clough et al., 2002; Nicholls, Polman, Levy & Backhouse, 2008). In a study with 219 pairs of monozygotic and dizygotic twins, differences in mental toughness were largely due to genetic and non-shared environmental influences (Horsburgh et al., 2009). Moreover, all MTQ subscales and the overall toughness index were correlated with the Big-Five personality factors in the expected way, supporting the notion that mental toughness is a trait-like construct. With regard to criterion validity, studies have showed that mentally tough individuals perceived less exertion during intensive physical activity and that more mentally tough participants performed better on a cognitive planning task after completing a series of motor tests, especially when they received negative feedback (Clough et al., 2002). 3

5 Purpose of the present study As highlighted above, the MTQ has been primarily conceived as a tool for coaches and sport psychology practitioners. As a consequence, studies including both athletes and nonathletes are sparse. The purpose of the present study was, therefore, to test the factor structure and psychometric properties of the MTQ in a sample of healthy, but not explicitely high-performing adolescents. Moreover, this study explores how mental toughness is related to perceived stress and depressive symptoms. Last, this study examined whether participants with high toughness scores are more resilient against stress. Hypotheses Based on the literature discussed above, the following hypotheses were tested: Hypothesis 1: The second-order factor structure of the MTQ48 can be confirmed by means of confirmatory factor analysis (CFA). Hypothesis 2: Both overall toughness indices and the MTQ subscales have adequate internal consistency. Hypothesis 3: The MTQ subscales are highly correlated with both overall toughness indices. Hypothesis 4: Moderate to high correlations exist between the various MTQ subscales. Hypothesis 5: The MTQ short and long forms are highly correlated with each other. Hypothesis 6: All MTQ indices are negatively correlated with perceived stress and depressive symptoms. Hypothesis 7: The likelihood of depressive symptoms decreases among participants with high toughness scores if they face stress. Method Participants and procedures Participants were 284 male (n=99) and female (n=185) high school students living in the German-speaking, North-Western part of Switzerland. The mean age was significantly higher (F(1,283)=5.60, p <.05) among male (M = 19.05, SD = 5.00) compared to females participants (M = 17.83, SD = 3.58). Participants received detailed information about the purpose of the study and about the voluntary basis of their participation. All participants were assured of the confidentiality of their responses and gave informed consent. Prior to commencing the study, approval for this project was granted by the local ethical committee. Instruments Mental toughness Participants were asked to fill in the 48-item MTQ (Clough et al., 2002), which measures total mental toughness and its eight subcomponents (for sample items see Table 1). Answers were given on a 5-point Likert-type scale ranging from 1 (strongly disagree) to 5 (strongly agree). Twenty-two items were reverse scored. Items were summed up to obtain the overall and subscale scores. Aspects of validity and reliability have been discussed above. To ensure optimal translations, we rigorously followed the procedure proposed by Brislin (1986). That is to say, the English items were translated into German, and then backtranslated into 4

6 English by an independent translator. Consensus was reached on a final version that was subjected to the translation-retranslation process. Perceived stress Perceived stress was assessed with the 10-item Perceived Stress Scale (PSS: Cohen, Kamarck & Mermelstein, 1983). The PSS draws on cognitiv-transactional stress theory (Lazarus & Folkman, 1984) and measures the degree to which respondents find their lives unpredictable, uncontrollable, and overloading. Answers were given on a 5-point Likert-type scale anchored at 1 (never) to 5 (very often). Four items were reverse scored. The mean was calculated in order to obtain an overall score. Adequate validity and reliability of the PSS have been established previously (e.g. Leung, Lam & Chan, 2010). Depressive symptoms The Beck Depression Inventory (BDI: Beck, Ward, Mendelson, Mock & Erbaugh, 1961) was used to assess severity of depressive symptoms. The BDI consists of 21 items including a range of affective, behavioral, cognitive, and somatic symptoms that are indicative for unipolar depression. Participants were asked to select from four alternative responses that reflect increasing levels of depressive symptomatology. Possible scores ranged from 0 to 63 with higher scores indicating more depressive symptoms. Adequate validity and reliability of the BDI have been demonstrated in prior investigations (e.g. Carter & Dacey, 1996). Data analysis CFA was performed using AMOS 17.0 (SPSS Inc., Chicago, IL). The process of analysis was based on a stepwise procedure (Gerbing & Anderson, 1988) including the specification of the a priori hypothesized model, the examination of model misspecification, the respecification of the a priori model and the comparison of the a priori model with the adjusted model. The analysis of the hypothesized second-order model was based on a maximumlikelihood estimation. As recommended (e.g. Hu & Bentler, 1999), several indices were used to evaluate the overall model fit. Beside the Chi 2 goodness-of-fit statistics, which are likely to become significant with increasing sample size, the comparative fit index (CFI), the root mean square error of approximation (RMSEA), and the standardized root means square residual (SRMR) were included as additional fit indices. For the CFI and PClose, values >.90 and.50 indicate good model fit, respectively. For the RMSEA and SRMR, values.05 and.08 point to good model fit, respectively (Hu & Bentler, 1999). Besides the overall goodness-offit indices, factor loadings were inspected to judge the relative contribution of each indicator to the latent factor. Although no golden standard cutoff exists for the size of factor loadings, Shevelin and Miles (1998) proposed to consider loadings between as low, between as medium and.70 as high. Based on prior research (Leung et al., 2010), we decided to retain only items with factor loadings.40. Cronbach s alpha values and itemtotal correlations (r it ) were computed to test the internal consistency of the original and revised scales. Correlations were calculated to explore the association between total toughness, the MTQ subscales, stress and depressive symptoms. Additionally, ten hierarchical regression analyses were performed to determine whether stress interacted with mental toughness in the prediction of depressive symptoms. To control for demographic background, gender and age were entered in the first step. Stress and mental 5

7 toughness were then entered in the second step and the interaction term of Stress x Mental Toughness in the third step. To prevent problems associated with multicollinearity, stress and mental toughness were centered before calculating the interaction term. Correlations and regression analyses were carried out using SPSS 16 (SPSS Inc., Chicago, IL). Results Factor structure and loadings The original model was based on 48 observed measures. As proposed by Clough et al. (2002), four second-order-factors were distinguished representing the control, challenge, commitment and confidence dimensions. Control and confidence were composed of two first-order constructs. The fit of the initial model was not adequate (Chi 2 /df = 2.46, p <.001, CFI =.68, PClose =.00, RMSEA =.07, SRMR =.08). After modifications were made, the model fit improved resulting in adequate goodness-of-fit indices (Chi 2 /df = 1.64, p <.001, CFI=.87, PClose =.81, RMSEA =.05, SRMR =.06). Nevertheless, the factor loadings varied from.10 to.74, indicating that not all items represented the latent construct well. In total, 11 items had factor loadings <.40 and were therefore excluded from further analyses (item 9R, 11R, 19, 26R, 33R, 34, 35R, 37R, 38, 43, 45). After exclusion of these items, the model fit was good (Chi 2 /df = 1.62, p <.001, CFI=.91, PClose =.76, RMSEA =.05, SRMR =.05) and factor loadings ranged from.42 to.70. All second-order factors were correlated and sufficiently explained by the first-order constructs (Figure 1). Psychometric properties of the MTQ Table 1 displays the psychometric properties of study variables. The Cronbach s alpha values of the MTQ subscales ranged from.57 to.94 and generally exceeded the recommended level of.70. The Cronbach s alpha of the emotion control subscale was critical, but improved after exclusion of four items with unsatisfactory factor loadings (original =.49). Bivariate associations Table 2 provides the correlations between the study variables. The findings show that all MTQ subscales were highly correlated with both overall indices. High correlations also existed between the various MTQ subscales. The MTQ long and short forms were strongly associated. Finally, high mental toughness was associated with lower stress and depressive symptoms. Except for interpersonal confidence, most of the coefficients indicated strong relationships. Last, a strong relationship existed between high perceived stress and increased depressive symptoms. Stress-buffer hypothesis Table 3 demonstrates that mentally tough participants are more resilient against stress. Significant main effects for perceived stress and mental toughness occurred across all toughness indicators. Likewise, significant interactions occurred between stress and all MTQ subscales explaining between 1% and 3% of additional variance. To provide an example, Table 3 showes that age and gender explained 7% of variance in depressive symptoms, p < 6

8 .01. The inclusion of the challenge subscale and perceived stress resulted in a significant R 2 - increment and 37% additionally explained variance, p <.001. Both challenge, = -. 18, p <.01, and stress, =.52, p <.001, were independent predictors of depressive symptoms. Finally, the interaction term between Challenge x Stress explained 2% of variance beyond that of the main effects, p <.01. The significant regression weight, = -.16, p <.01, indicates that high challenge is associated with lower depressive symptoms if participants experience high stress. Discussion Main findings Clough et al. (2002) have used a theory-driven approach to develop the MTQ. Drawing on Kobasa s hardiness theory, the MTQ has its fundament in health psychology and is applicable to research inside and outside sport. Using a confirmatory approach, the findings of this study provide support for the internal and external construct validity and reliability of the MTQ. The key findings are that (i) after deletion of 11 items with unsatisfactory factor loadings the empirical data fitted well the hypothesized second-order factor structure, (ii) the two overall indices and eight subscales of the MTQ were internally reliable, (iii) the overall indices and subscales were correlated in the expected way, (iv) high mental toughness was associated with lower stress levels and depressive symptoms, and (v) mental toughness mitigated the relationship between high stress and depressive symptoms. Together, seven hypotheses were formulated and each of these will now be discussed separately. First, the (higher-order) factor structure of the MTQ was confirmed by means of CFA. This is in line with previous confirmatory research (Horsburgh et al., 2009). Nevertheless, the present study shows that not all items were loading adequately on the hypothesized factors. The unsatisfactory factor loadings might be attributable to cultural differences in the management of time and emotions (e.g. Mesquisa & Walker, 2003). Alternatively, some items might be interpreted differently by athletes and non-athletes. Second, the overall toughness indices as well as most of the MTQ subscales had acceptable internal consistency (cp. Clough et al., 2002; Crust & Azadi, 2010; Nicholls et al., 2009). The reliability of the emotion control subscale was critical, which corroborates a prior study, in which the reliability of this subscale was improved after deleting two items (Kaiseler et al., 2009). Third, the overall toughness indices and the MTQ subscales were highly correlated with correlation coefficients ranging between r = , p <.001. Thus, the strength of association was comparable to previous studies (Clough et al., 2002). Fourth, the correlations between the various MTQ subscales were high. The correlations ranged between r = , p <.001. The strength of relationships exceeded the one found in previous research (Clough et al., 2002). Fifth, the short and long form of the MTQ were highly correlated with each other (Clough et al., 2002). Again, the correlation found was comparable to previous research (Clough et al., 2002). Sixth, mental toughness was negatively correlated with perceived stress and depressive symptoms. This was expected because depression is a mental disorder, which encompasses symptoms on an emotional (e.g. helplessness, listlessness), motivational (e.g. withdrawal, avoidance), cognitive (e.g. hopelessness, rigidity), somatic (e.g. trouble, irritability) and motor (e.g. agitation, stooping posture) level (Beck & Alford, 2009). Thus, it 7

9 seems evident that such kind of dysfunctional thoughts and maladaptive behavior tendencies are incompatible with the control, challenge, commitment and confidence attributes, which characterize a mentally tough individual. Furthermore, the strong negative relationship between perceived stress and mental toughness can be attributed to the fact that according to transactional stress-theory (Lazarus & Folkman, 1984), stress is defined as a state of imbalance between internal or external demands and personal or social resources available to cope with a potential stressor. The notion that mentally tough individuals are characterized by a strong tendency to view their personal environment as controllable, to perceive themselves as capable and influential, to stay committed even under adverse circumstances, and to consider problems as natural challenges, which allow personal growth, may explain why they usually perceive less stress or have higher stress tolerance levels. Furthermore, the relationships found between mental toughness, depressive symptoms and stress support past research showing a close relationship between psychological resources and psychopathological symptoms (e.g. Orth, Robins & Roberts, 2008). Furthermore, the results resemble previous investigations, in which moderate to high correlations were found between the 48-item overall toughness index and indicators of mental well-being (Clough et al., 2002; Nicholls et al., 2008). With regard to perceived stress, Kaiseler et al. (2009) found that mental toughness was negatively correlated with the intensity of a self-selected (sport-specific) stressor. Moreover, several authors reported that the MTQ was positively associated with problem-oriented coping, while negative relationships existed with avoidance coping strategies (Crust & Azadi, 2010; Kaiseler et al., 2009; Nicholls et al., 2008). Finally, the strong positive correlation found between the PSS and BDI supports previous reviews pointing out a close relationship between stress and psychopathological symptoms (Grant et al., 2006). Seventh, this study indicates that beyond bivariate relationships mental toughness moderates the relationship between perceived stress and depressive symptoms. This finding was expected as prior studies have proved that hardiness helps individuals coping with stress (Maddi, 2004). Similarly, a recent review of adolescent research proved that individual characteristics such as self-regulatory beliefs or optimism moderate the relationship between stress and perceived well-being (Grant et al., 2006). The effect sizes in this study varied between 1% and 3% of explained variance, which is a considerable amount given that detecting interaction effects in field studies is difficult (McClelland & Judd, 1993). The results of the present study extend prior research by assessing mental toughness in a broad sample of healthy adolescents, though not exclusively athletes.. Therefore, our results imply that the German version of MTQ is a valid and applicable instrument among non-athelete adolescents, too. Additional strengths of this study are that a confirmatory approach was used to test the higher-order structure of the proposed toughness model, external construct validity was examining from an outside sport resilience perspective, a backward translation procedure was applied and widely accepted instruments were chosen to assess stress and depressive symptoms. Some limitations should be noted. First, only self-reports measures were used. Second, the analyses were restricted to high school students. Third, the cross-sectional design did not allow a causal interpretation of the data. Fourth, no separate CFA and regression analyses were performed for male and female participants due to the relatively small sample size. 8

10 Implications and future research Further verification of the psychometric properties of the MTQ are required. Moreover, longitudinal research is needed in working towards the proof of causal evidence. In addition, more studies with an outside sport perspective are warranted, in which mental toughness is considered as a health resource. For instance, a biopsychological approach seems helpful to find out whether mental toughness affects the physiological reactivity during laboratory or real life stressor tasks. Finally, more research is needed to understand whether mental toughness can be improved by means of exercise training and whether increases in mental toughness explain how exercise contributes to the reduction of depressive symptoms. References Beck, A. T., & Alford, B. A. (2009). Depression. Causes and treatment. Philadelphia: University of Pennsylvania Press. Beck, A. T., Ward, C. H., Mendelson, M., Mock, J., & Erbaugh, J. (1961). An inventory for measuring depression. ARchives of General Psychiatry, 4, Brislin, R. W. (1986). The wording and translation of research instrument. In W. J. Lonner & J. W. Berry (Eds.), Field methods in cross-cultural research (pp ). Beverly Hills: Sage. Carter, C. L., & Dacey, C. M. (1996). Validity of the Beck Depression Inventory, MMPI, and Rorschach in assessing adolescent depression. Adolescence, 19, Clough, P., Earle, K., & Sewell, D. (2002). Mental toughness: The concept and its measurement. In I. Cockerill (Ed.), Solutions in sport psychology (pp ). London: Thomson Learning. Cohen, S., Kamarck, T., & Mermelstein, R. (1983). A global measure of perceived stress. Journal of Health and Social Behavior, 24, Crust, L. (2008). A review and conceptual re-examination of mental toughness: Implications for future researchers. Personality and Individual Differences, 45, Crust, L., & Azadi, K. (2010). Mental toughness and athletes' use of psychological strategies. European Journal of Sport Science, 10, Gerbing, D. W., & Anderson, J. C. (1988). An updated paradigm for scale development incorporating unidimensionality and its assessment. Journal of Marketing Research, 25, Grant, K. E., Compas, B. E., Thurm, A. E., McMahon, S. D., Gipson, P. Y., Campbell, A. J., et al. (2006). Stressors and child and adolescent psychopathology: Evidence of moderating and mediating effects. Clinical Psychological Journal, 26(3), Horsburgh, V., Schermer, J., Veselka, L., & Vernon, P. (2009). A behavioural genetic study of mental toughness and personality. Personality and Individual Differences, 46, Hu, L.-T., & Bentler, P. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling, 6, Jones, G., Hanton, S., & Connaughton, D. (2002). What is this thing called mental toughness? An investigation of elite sport performers. Journal of Applied Sport Psychology, 14(3), Jones, G., Hanton, S., & Connaughton, D. (2007). A framework of mental toughness in the world's best performers. The Sport Psychologist, 21, Kaiseler, M., Polman, R. C. J., & Nicholls, A. R. (2009). Mental toughness, stress, stress appraisal, coping and coping effectiveness in sport. Personality and Individual Differences, 47, Kobasa, S. C. (1979). Stressful life events, personality, and health: An inquiry into hardiness. Journal of Personality and Social Psychology, 37(1), Lazarus, R. S., & Folkman, S. (1984). Stress, appraisal, and coping. New York: Springer. Leung, D. Y. P., Lam, T. H., & Chan, S. S. C. (2010). Three versions of Perceived Stress Scale: Validation in a sample of Chinese cardiac patients who smoke. BMC Public Health, 10, Loehr, J. E. (1986). Mental toughness training for sports: Achieving athletic excellence. Lexington: Stephen Greene Press. Mack, M. G., & Ragan, B. G. (2008). Development of the mental, emotional, and bodily toughness inventory in collegiate athletes and nonathletes. Journal of Athletic Training, 43, Maddi, S. R. (2004). Hardiness: An operationalizatiion of existential courage. Journal of Humanistic Psychology, 44,

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