Background About 2 out of 3 competitive runners sustain at least one health problem every season; most of these problems are non-traumatic injuries with gradual onset. The main known risk indicator for sustaining a new running-related injury episode is a history of a previous injury, suggesting that behavioural habits are part of the causal mechanisms.

Objective To explore competitive runners' cognitive appraisals of perceived symptoms on injury and illness and how these appraisals are transformed into behaviour.

Design Qualitative study using semi-structured interviews for data collection.

Setting Swedish competitive middle- and long-distance runners.

Participants 14 runners from the national top 15 list.

Assessment of Risk Factors Qualitative research methods were used to categorize interview data and perform a thematic analysis.

Main Outcome Measurements Categories resulting from the analysis were used to construct an explanatory model.

Results Symptoms interpreted to be caused by illness or injury with a sudden onset were found to lead to immediate responses and changes to training and competition programs (activity pacing). In contrast, perceptions interpreted to be due to injuries with gradual onset led to varied behavioural reactions. These behavioural responses were planned with regard to short-term effects and were characterized by indifference and neglect of long-term implications, consistent with an overactivity behavioural pattern. The latter pattern was consistent with a psychological adaptation to stimuli that is presented progressively to the athlete.

Conclusions Competitive runners appraise whether a health problem requires immediate withdrawal from training based on whether the problem is interpreted as an illness and/or has a sudden onset. The ensuing behaviours follow 2 distinct patterns that can be termed activity pacing and overactivity. Recurrent health problems among competitive runners can be addressed through the premise that overactivity behaviours are balanced by support of health literacy and psychological flexibility.