Table 1.

Researches related to question 1

Reference	Age   (years)	Sample	Measurements	Whether it causes stress disorder	Symptoms and characteristics of stress disorder	Factors mentioned
Shuer ML et al. 1997 [13]	Average= 19.5	280 Men 137 Women 143	IES	Athletes with acute and chronic sports injury showed symptoms of stress disorder.	(1) There was no significant difference in the score of intrusion symptoms between the chronically injured athletes and the fire victims. (2) The score of avoidance symptoms of long-term injured athletes was significantly higher than that of fire and earthquake victims. (3) There was no significant difference in avoidance behaviour score, between patients with bone injury caused by accident and athletes with acute and chronic injuries.	Sex
Newcomer RR et al. 2003 [18]	13–18	283 Men 143 Women 140	IES	The IES score of injured athletes increased by 35%–49% before and after the injury.	Athletes with a recent history of injury show more serious invasive thinking and avoidance behaviour.	Age
O’Neill DF 2008 [22]	13–19	459 Men 277 Women 182	Interview PANAS Injury contagion and performance testing	After witnessing the injury, teammates showed PTSD related symptoms.	(1) Fear of injury increased when teammates were injured. (2) Female athletes’ emotional swings were more pronounced after teammates were injured.	Sex
O’Connor JW 2010 [25]	18–30	35 Men 13 Women 22	TSI Brief COPE Inventory	Over 1/3 of the injured athletes had TSI scores over 65, the correlation between sports injury and posttraumatic distress exists.	Coping styles and injury severity were not related to the intensity of traumatic symptoms.	Coping style Injury severity
Edmed SL et al. 2015 [29]	/	122 Men 40 Women 82	Sport-mTBI vignette NSI PCL-C IPQ-R Perceived injury desirability	14.6% athletes without diagnostic, 20% athletes diagnosed with a concussion, and 19.5% athletes diagnosed with mTBI expected more significant PTSD symptom disturbance than the clinical cut-off in the control after reading the Sport-mTBI vignette.	There was no significant difference in expected PTSD symptoms when diagnosed with mTBI or concussion, or given no diagnosis.	Diagnosis
Xu S et al. 2018 [24]	/	268	The PTSD self-rating scale The international personality item pool- five-factor model measure SCSQ Colorado injury reporting system	There is a significant correlation between the degree of sports injury and stress disorder severity.	(1) The negative coping style plays a complete mediating effect between the degree of sports injury and posttraumatic stress disorder. (2) The mediating effect of negative coping style between the degree of injury and stress response is moderated by neuroticism personality.	Coping style Personality The severity of injury
Brassil HE et al. 2018 [26]	18–24	124	PC-TSS Self developed scale based on DSM-V	The score of posttraumatic stress disorder in the concussion group was significantly higher than in the healthy group. The score of stress disorder symptoms were increased considerably after injury.	For athletes with a history of sports-related concussion injuries, the most severe problem is a sleep disorder, followed by avoidance symptoms.	Type of sports injuries
Padaki AS et al. 2018 [19]	14.5±2.7	24 Men 12 Women 12	AIMS IES-R	After a sports injury, more than 80% of athletes showed symptoms related to stress disorder.	(1)After ACL rupture, more than 87.5% of the athletes had avoidance symptoms, 83.3% admitted to avoidance symptoms, and 75% had hyperarousal symptoms. (2)ACL ruptured athletes aged 15–21 have more severe symptoms of posttraumatic stress disorder than young athletes under 14 years of age. (3) The emotional trauma of female patients is more significant than male patients. (4) Patients with high athletic identities experienced greater emotional trauma than those with lower identities. (Not statistically significant)	Age Sex Identity
Bateman A et al. 2019 [23]	18–24	46 Men 30 Women 16	IES-R GSES	Sports injury has a specific predictive effect on posttraumatic stress disorder, especially for hyperarousal symptoms.	The results show that self-efficacy does not affect the development of PTSD.	Self- efficacy
Appaneal RN et al. 2007 [16]	19–25	12 Men 12	HR EDA(SCL SCR) BAM SUDS IES POMS LESCA	When watching a video of an injury, the physical and psychological stress responses of the athletes with a history of injury were significantly higher than the healthy group.	Injured athletes’ skin conductivity response and psychological stress pain were significantly higher than the control group.	/

IES Impact of Event Scale, IES-R Impact of Event Scale – Revised, PANAS Positive and Negative Affent Schedule, PTSD post-traumatic stress disorders, TSI traumatic stress inventory, PCL-C PTSD Checklist-Civilian Version, mTBI mild traumatic brain injury, NSI neurobehavioural symptom inventory, IPQ-R Revised Illness Perception Questionnaire, SCSQ Simplified Coping Style Questionnaire, PC-TSS post-concussion total symptom scores, DSM-V diagnostic and statistical manual of mental disorders, AIMS Athletic Identity Measurement Scale, GSES General Self-Efficacy Scale, HR heart rate, EDA Electrodermal Activity, SCL skin conductance level, SCR skin conductance response, BAM brief assessment of mood, SUDS Subjective Units of Distress Scale, POMS profile of mood states, LESCA Life-event Scale for Collegiate Athletes