Exercise as it relates to Disease/Does exercise improve mental health outcomes in younger people?

This Wikibooks page observes the research article 'Effects of exercise on mental health outcomes in adolescents: Findings from the CrossFit™ teens randomized controlled trial' done by Eather, N., Morgan, P. J., & Lubans, D. R. (2016)[1]

What is the background to this research?Edit

The World Health Organisation defines mental health as 'a state of well-being in which every individual realizes his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to her or his community.'[2] Possessing good mental health is vital and leads to a greater quality of life, though one in seven young Australians experience a mental health condition.[3] Having poor mental health can disrupt their way of life and may lead to further detrimental health conditions in the long-term.

CrossFit™ is a branded fitness regimen that incorporates a constant variety of high intensity functional movements. Designed to build strength and endurance in participants through challenging but achievable workouts.[4] Regular participation in physical activity is associated with a variety of physical and mental health benefits for younger people.[5] Evidence has suggested that exercise may be an often-neglected intervention in mental health care.[6] Exercise has been known to improve mental health by reducing depression, anxiety and negative mood and by improving self-esteem and cognitive function.[6]

Where is the research from?Edit

The study was conducted at one secondary school located in the Hunter Region, NSW, Australia in 2013 by Eather, Morgan, & Lubans.[1] The study was approved by the University of Newcastle, NSW, Australia and registered with the Australian and New Zealand Clinical Trials Registry.[1]

What kind of research was this?Edit

The study was an assessor-blinded Randomized Controlled Trial (RCT). In clinical research, RCTs are considered to be the most effective way to study the safety and efficacy of new treatments.[7] Researchers were blinded to treatment conditions at baseline and follow-up assessments when administering questionnaires for participants to fill out.[1]

Hypothesized mediators

  • Perceived body fat
  • Strength and appearance
  • General self-concept

Hypothesized moderators

  • Sex
  • Baseline levels of psychological distress

Information from participants were collected through questionnaires and mediation was assessed through IBM SPSS software (version 22.0). Hypothesized moderators were assessed with linear mixed models and Cohen's d effect sizes (indicates the standardised difference between two means) were evaluated.[1]

What did the research involve?Edit

96 students (15.4 (0.5) years, 51.5% female) from the school participated in an 8-week CrossFit™ Teens program to see the impact exercise has on mental health outcomes in adolescents, and to explore potential moderators and mediators. The participants were randomized into intervention or control conditions. The resistance training program was designed by accredited CrossFit™ instructors whom specifically designed it for secondary-school aged children.[1]

Intervention (n=51)

  • CrossFit™ program delivered twice a week during their normal PE and sport lesson classes (60 min each). A typical session included a dynamic warm-up, a technique-based skill session, a Workout of the Day and a stretching session.

Control (n=45)

  • Students participated in a 60 min/week sport lesson of their choice and their usual 60 min/week HPE lesson (eight fitness lessons focusing on different fitness activities) delivered by their PE teacher over the 8-week intervention period.

Participants were also required to complete questionnaires that assessed their psychological health (psychological distress and self-esteem) in the study:

  • Strength and Difficulties Questionnaire (SDQ) - Generates a total difficulties score which provides an indication of the degree of overall distress and social impairment associated with psychological attributes. Therefore, scores above 15 on the Total Difficulties Score identified students "at-risk" of developing mental disorders.[1]
  • Physical Self-Description Questionnaire (PSDQ) - Used to measure multi-dimensional physical self-concepts in adolescents. Contains 6 sub-scales: physical appearance, strength, perceived body fat, physical self-concept and global self-esteem.[1]

What were the basic results?Edit

This study showed that participation in the CrossFit™ Teens resistance training program had no significant intervention effects or improvements on mental health or potential mediators in the full study sample, but there were induced improvements in self-esteem and physical self-perception levels in participants considered 'at-risk' of developing psychological disorders.[1] All sessions were delivered with a 94% attendance rate.[1] The tables below show that intervention participants considered at-risk had significant improvements and larger effect scores than the not at-risk.

Not at-risk

Self-esteem Perceived body fat Perceived appearance Physical self-concept Total difficulties score
d = 0.32 d = 0.39 d = 0.01 d = 0.24 d = 0.36


Self-esteem Perceived body fat Perceived appearance Physical self-concept Total difficulties score
d = 1.35 d = 1.05 d = 0.95 d = 1.96 d = 0.70
  • (d = mean difference in change scores/pooled variance)
  • Interpreted as: 0.20 = small, 0.50 = moderate and 0.80 = large effect.[1]


  • The study sample was relatively small and homogenous.
  • The study was not adequately powered for multiple analyses which increased the likelihood towards a positive bias
  • The study was too short which may have limited the potential outcomes of greater improvements in mental health.[1]

What conclusions can we take from this research?Edit

This research concluded that exercise does not significantly improve mental health outcomes in adolescents, though it does improve their perception of themselves. In a separate study, Costigan et al. also found that a resistance exercise program had minor improvements in adolescents' well-being and perceived appearance.[5] Therefore, this provides evidence that exercise may be used as a supporting tool in improving mental health. Regardless, everyone should be doing some sort of physical activity to reap the benefits and to stay healthy.

Practical adviceEdit

Looking after an individual's mental health is crucial to a higher quality of life, whether it be in adolescence or adulthood. Therefore, incorporating physical activity into their daily life is beneficial, both physically and/or mentally. Also incorporating positive coping strategies may decrease the risk of developing mental health difficulties such as talking to a friend, counseling, practising meditation or other relaxation techniques and increasing resilience in adolescents to handle life's difficulties.[3]

Due to the lack of significant changes in mental health outcomes in the full study sample, further research in the future may be needed.

Further information/resourcesEdit

For further information on mental health/mental health support, read below:


  1. a b c d e f g h i j k l Eather, N., Morgan, P. J., & Lubans, D. R. (2016). Effects of exercise on mental health outcome in adolescents: findings from the CrossFit™ teens randomized controlled trial. Psychology of Sport and Exercise, 26, 14-23. https://doi.org/10.1016/j.psychsport.2016.05.008
  2. Mental health: a state of well-being. (2014). World Health Organization. Available from http://www.who.int/features/factfiles/mental_health/en/
  3. a b beyondblue. (2017). Youthbeyondblue.com. Available from https://www.youthbeyondblue.com/footer/stats-and-facts
  4. What is CrossFit - CrossFit: Forging Elite Fitness. (2017). CrossFit.com. Available from https://www.crossfit.com/what-is-crossfit
  5. a b Costigan, S. A., Eather, N., Plotnikoff, R. C., Hillman, C. H., & Lubans, D. R. (2016). High-intensity interval training for cognitive and mental health in adolescents. Medicine & Science in Sports & Exercise, 48(10), 1985-1993. https://doi.org/10.1249/MSS.0000000000000993
  6. a b Sharma, A., Madaan, V., & Petty, F. D. (2006). Exercise for Mental Health. Primary Care Companion to The Journal of Clinical Psychiatry, 8(2), 106.
  7. Kabisch, M., Ruckes, C., Seibert-Grafe, M., & Blettner, M. (2011). Randomized Controlled Trials: Part 17 of a Series on Evaluation of Scientific Publications. Deutsches Ärzteblatt International, 108(39), 663–668. http://doi.org/10.3238/arztebl.2011.0663