How are biomechanical and psychosocial factors associated with injuries across one season in Swedish elite and sub-elite female soccer players?

Abstract Background Soccer is a high-intensity contact sport, and the patterns and burden of injuries can vary based on age, sex, and player level. To better understand injury occurrence, it is important to identify biopsychosocial factors that are associated with injuries. Our study aimed to investigate whether various biomechanical and psychosocial factors associate with time-loss injuries and reported injury problems in the dominant and non-dominant leg across one season in elite and sub-elite female soccer players. Methods This prospective study followed 244 elite and sub-elite female soccer players (22 years, SD ± 4) from divisions 1–3 over one season. Data on investigated factors were collected at baseline, while injury data were collected every four weeks. Negative binomial regression analyses were used to examine associations between the investigated factors and injury outcomes. Results For time-loss injuries involving the dominant leg, higher levels of hip strength were associated with a lower injury incidence in players aged 16–19 years (IRR = 0.95, 95% CI 0.92–0.98), while this association was not observed in the older age groups. Higher levels of fear avoidance were associated with a higher injury incidence (IRR = 1.08, 95% CI 1.03–1.14). For the non-dominant leg, playing in division 2 was associated with a higher injury incidence (IRR = 2.75, 95% CI 1.23–6.16) compared with division 1. Greater ankle dorsiflexion was associated with a lower injury incidence (IRR = 0.91, 95% CI 0.84–0.99), and higher levels of hip strength were associated with a lower injury incidence (IRR = 0.98, 95% CI 0.96–0.99). Regarding injury problems, higher levels of fear avoidance were associated with a higher rate of reported injury problem observations for both the dominant (IRR = 1.04, 95% CI 1.02–1.07) and non-dominant leg (IRR = 1.04, 95% CI 1.02–1.06). Conclusion Biomechanical factors, including hip strength, and psychosocial factors such as fear-avoidance behaviour were associated with time-loss injuries and reported injury problems in female elite and sub-elite soccer players. The separate leg-specific analyses showed different patterns of associations in the dominant and non-dominant leg. Given the relatively small effect sizes, the findings should be considered hypothesis-generating and their clinical relevance requires further investigation. Trial registration Retrospectively registered in Clinical Trials Gov, date of registration 13/03/2022. Clinical trials identifier NCT05289284.