Original research
Psychosocial stress as a predictor of injury in elite junior soccer: A latent growth curve analysis

https://doi.org/10.1016/j.jsams.2013.10.242Get rights and content

Abstract

Objectives

To investigate by use of a latent growth curve analysis framework whether athletes’ individual levels and changes in hassle and uplift levels over a 10-week period could predict injury outcome in an elite junior soccer population.

Design

A prospective design with repeated measurement points.

Methods

Participants were 101 Swedish elite junior soccer players (67 males and 34 females). Ten sets of measures were taken on a weekly basis during which participants completed the Hassles and Uplifts Scale (HUS). Latent growth curve models were used to examine whether the level and change in psychological stress could predict the frequency of injury over the 10-week period.

Results

The results show that injury occurrence was significantly associated with both the initial level of daily hassle and the change in daily hassle. High initial daily hassle levels and a smaller decrease in daily hassles were associated with injury occurrence. Moreover, injury occurrence was significantly associated with a greater decrease in daily uplift.

Conclusions

The findings highlight the importance of focusing on state variables using prospective designs and appropriate analysis of within-person change to detect complex and dynamic associations across time in injury-prediction research.

Introduction

In both male and female Swedish elite soccer populations, researchers have found injury rates to be between 65% and 95% per year.1 Pre-injury research has identified a number of factors that could increase injury risk among athletes. For example, Bahr and Krosshaug2 developed a theoretical model in which internal risk factors (such as health, physical fitness, skill level, and psychological factors) are associated with an athlete's predisposition towards increased injury risk. The predisposed athlete is then exposed to external risk factors (such as sports equipment and environment) that may render him or her susceptible to a higher risk of injury. Owing to the complex interactions of internal and external risk factors, it has been suggested that injury researchers should adopt prospective designs in order to monitor changes in injury susceptibility over a period of time.3 This study focuses on the ways in which changes in psychosocial stress influence injury risk among Swedish elite junior soccer players.

Concerning the psychosocial factors that may influence injury risk among athletes, several models have been proposed. One of the most influential and well known is Williams and Andersen's4 theoretical model of stress and athletic injury, which suggests that specific psychosocial risk factors influence an athlete's appraisal of a potentially stressful situation. The risk factors are divided into three categories: personality factors (such as proneness to anxiety), history of stressors (such as negative life-event stress and daily hassle), and coping (such as acceptance). How an athlete appraises a situation influences the strength of the stress response s/he will experience. This, in turn, may influence the athlete's cognitive (e.g., peripheral vision) and physiological (e.g., fatigue level) abilities. These changes in cognitive and physiological abilities potentially lead to an increased risk of injury.

Findings from empirical studies using a nomothetic approach have in general supported this model. For example, personality variables such as trait5 and state6 anxiety have been found to have a positive correlation with injury risk among athletes. Regarding the history of stressors and injury occurrence, empirical research has shown distinct support for a positive correlation between major stressors (e.g., negative life-event stressors) and injury occurrence.4, 7, 8 In addition, several empirical studies using an idiographic approach have been conducted in this field. Most of these have found that athletes’ pre-injury experiences could be classified in accordance with Williams and Andersen's suggested categories. For example, one interview study found that both life-event stress and personal factors (such as worry and anxiety) were present in the athletes’ stories.9 Given that the relationship between psychological variables (e.g. personal traits and stress) and injury risk could be influenced by hassles,10 the injury risk to which an athlete is exposed could fluctuate as a consequence of the level of hassles. Daily hassles can be defined as everyday irritations, such as minor problems at work, not getting enough sleep, and losing things.11 Results from other studies also support the link between a high level of hassle and increased risk of injury.12, 13 When discussing daily stressors, such as hassles, daily uplifts should also be mentioned. Daily uplifts can be defined as events that make one feel good; for example, they produce feelings of joy, gladness, or satisfaction.11 Even if high levels of uplift have been found to be associated with lower levels of perceived stress,14 this relationship has not, to the best of our knowledge, been addressed in the psychology of injury literature.

Previous research in sports-injury literature has largely focused on major stressors (i.e., acute life events such as the death of a relative or a job loss7, 8) without taking into consideration individual differences in state variables (i.e. hassle and uplift). Moreover, analyses used in previous research have been predicated on means or paths (e.g. repeated-measures ANOVA), without an acknowledgement of the potential influence of individual differences.15, 16 In the present study, we instead use a latent growth curve analysis (LGC) to investigate how the intercept (starting point) and slope (change) of the level of hassle are associated with injury occurrence. More specifically, using latent growth curve models (LGCMs), it is possible to investigate both inter- and intra-individual change. Hence, LGC includes a powerful and flexible methodology to model intra-individual changes, inter-individual differences in intra-individual change, and the ways that level and true change may predict other outcomes.15, 16 Consistent with these suggestions, our aim was to highlight the concept of change (in hassle and uplift level, respectively) and how it might predict risk of injury. Consequently, the objective of this study was to investigate whether athletes’ individual levels and changes in levels of hassle and uplift during a 10-week period could predict injury outcome. We hypothesised that a high hassle level would be associated with an increased likelihood for injury (hypothesis A). Moreover, a low uplift level was hypothesised to be associated with a high injury risk (hypothesis B).

Section snippets

Method

The participants were 101 elite junior soccer players (67 males and 34 females), aged between 15 and 19 years (mean age [16.7 ± 0.9 yr]). They were high school students whose soccer programmes were certified by the Swedish Soccer Association (four schools in total). During the study period, the players practiced between 4.5 and 20 h per week [11.22 ± 3.22 h]. At the beginning of 2012, all players included in the study were injury free and in full training.

During the study period, 67 injuries were

Results

The hassle and uplift trajectories for the two groups (injured and uninjured players) appear in Fig. 1. This figure illustrates the growth curves in hassle and uplift for (1) the group of players that experienced an injury during the study, and (2) the group of players that did not experience an injury during the same period. In the figure, the injury group’ trajectories represent data from the pre-injury period only.

The baseline model, including daily hassle, showed acceptable fit: χ2 (df = 58; N

Discussion

The objective of this study was to investigate using an LGC framework whether athletes’ individual levels and changes in levels of hassle and uplift during a 10-week period could predict injury outcome. The result served to support both of our hypotheses namely that: (A) higher levels of hassle and (B) lower levels of uplift were associated with an increased injury risk. More specifically, the results show that both high initial levels of daily hassle and less decrease (less positive change) in

Conclusion

In sum, the results with a focus on within-person change suggest that high initial levels of and negative changes in daily hassle are associated with injury risk. Moreover, the results indicate that the injury risk to which a player is exposed can change over time. Regarding methodology, future studies should focus on state variables using prospective designs and appropriate analysis, focusing on intra-individual change (e.g. latent growth curve or latent class analysis) to detect differences

Practical implications

  • Risk of injury may fluctuate owing to changes in levels of both hassle and uplift.

  • Change in hassle is suggested to influence injury risk through changes in cognitive functions.

  • Uplift could potentially decrease the impact of stressors on injury risk.

Acknowledgements

We thank the participating coaches, players and medical staff for their cooperation. We also thank the Swedish Soccer Association, and in particular Johan Fallby, for their collaboration. Furthermore, we are grateful to Viktor Hallström for his research assistance in relation to data input. Moreover, we thank Assistant Professor Damien Clement for valuable feedback on earlier drafts of this report. No external financial support was provided for this study.

References (31)

  • C. Finch

    A new framework for research leading to sports injury prevention

    J Sci Med Sport

    (2006)
  • H.J. Fawkner et al.

    Athletic injury and minor life events: a prospective study

    J Sci Med Sport

    (1999)
  • T.E. Duncan et al.

    An introduction to latent growth curve modeling

    Behav Ther

    (2004)
  • M. Hägglund et al.

    Injuries among male and female elite football players

    Scand J Med Sci Sports

    (2009)
  • R. Bahr et al.

    Understanding injury mechanisms: a key component of preventing injuries in sport

    Br J Sports Med

    (2005)
  • J.M. Williams et al.

    Psychosocial antecedents of sport injury: review and critique of the stress and injury model

    J Appl Sport Psychol

    (1998)
  • L. Lavallee et al.

    The relationship of stress, competitive anxiety, mood state, and social support to athletic injury

    J Athl Train

    (1996)
  • J. Sibold et al.

    A comparison of psychosocial and orthopaedic data in injured college athletes: novel application of hurdle regression

    Athl Insight

    (2011)
  • U. Johnson et al.

    Psychological predictors of sport injuries among junior soccer players

    Scand J Med Sci Sport

    (2011)
  • T.M. Rogers et al.

    Mediating effects of peripheral vision in the life event stress/athletic injury relationship

    J Sport Exerc Psychol

    (2005)
  • U. Johnson

    Athletes’ experiences of psychosocial risk factors preceding injury

    Qual Res Sport Exerc Health

    (2011)
  • A. Ivarsson et al.

    Psychological predictors of injury occurrence: a prospective investigation of competitive Swedish soccer players

    J Sport Rehabil

    (2012)
  • A. De Longis et al.

    The impact of daily stress on health and mood: psychological and social resources as mediators

    J Pers Soc Psychol

    (1988)
  • B. Blackwell et al.

    The relationship of athletic injury to life stress, competitive anxiety, and coping resources

    J Athl Train

    (1990)
  • S. Folkman et al.

    Positive affect and the other side of coping

    Am Psychol

    (2000)
  • View full text