Approach to activity in pain: benefits and consequences of endurance despite severe pain

When people suffer from some kind of spontaneous pain in daily life, pain captures attention and presumably interrupts an ongoing activity [1]. From a perspective of self-regulation [2], pain may cause a motivational conflict between several “approach” or “avoidance” goals. Short-term, at least two goals, namely the wish to reduce pain on the one hand and maintaining the ongoing activity on the other, may be relevant. With respect to value-expectancy models [3], the choice will depend on how important the goal to maintain an activity is (i.e. value) and the strength of the belief that one can attain this goal (i.e. expectancy). Endurance in an activity is most likely to happen when both, value and expectancy are high. Imagine Peter, a marathon runner, who feels pain in his back during a run. Completing a whole marathon for the first time in his life is highly important to him (i.e. following a highly valued “approach goal”, due to his intense wish to be a healthy and sporty person) and also the expectancy that this will work despite the increasingly aching back. Full of anticipation he is highly optimistic and in a good mood. In case of successfully completing the run, he is most happy reaching his goals. Imagine another person, Mike, who feels back pain during his working day as a truck driver. He is afraid of not reaching his destination in time. Motivated to avoid critique of his employer, he decided to continue driving without a back-friendly break, feeling increasingly fatigued, irritated and with depressive mood. However, reaching his destination in time, he feels relieved. Both men decided to endure in a highly valued activity despite pain but differ with respect to positive or negative mood and the direction of their activity-related goals. At short-term, both men will experience significant benefit of their endurance behaviour, the successful outcome may act as a reinforcer in the sense of operant conditioning, leading to the maintenance of endurance behaviour. Today there is increasing evidence from experimental research supporting the self-regulation perspective. Healthy people who were confronted with a certain task, some of them while experiencing a painful stimulus, will decide to persist in an activity despite pain, when this activity was of high value, i.e. associated with a reward [4,5]. This kind of research intriguingly corroborate clinical findings in patients with subacute or chronic pain who reported high levels of endurance behaviour in situations with severe pain, addressed at “dysfunctional endurance” [6–8]. Moreover, the avoidanceendurance model of pain (AEM) [9] suggests two subgroups of patients with an endurance pain response pattern, namely patients showing signs of so-called eustress versus distress endurance responses (EER vs. DER), besides a well-known fear-avoidance subgroup. DER patients have been shown higher pain-related disability, more fatigue and less positive mood than EER [8,10] while both subgroups displayed higher pain intensity than an adaptive group and higher percentage of physical activity, especially in backstrain positions [10]. Interestingly, the DER patients showed a moderate level of avoidance besides high endurance. Using qualitative and quantitative analyses, Andrews and colleagues [11] described subgroups of patients with chronic pain who reveal high levels of physical activity despite pain, developing an increase in pain over time up to a moment when they turned into avoidance. Thus, the avoidance of pain-related activities might be not only occurring preventively due to high levels of fear/anxiety but also as a consequence of long periods of endurance associated with increases in pain. A few prospective studies indeed revealed that high levels of dysfunctional endurance predict higher levels of pain, i.e. low back pain [6,8,12], indicating that endurance despite severe pain may yield consequences in the long-term. The AEM suggests microtrauma in the musculoskeletal system, shown due to overload [13] as a repetitive occurring peripheral cause of pain, maintaining chronic pain besides suggested processes of central sensitisation. Clinical implications with a focus on dysfunctional pain endurance are manifold: (1) patients have to learn to realise a balance between short-term and adaptive pain-related avoidance and endurance, i.e. making and accepting breaks for recovery from a period of stress, (2) health care providers such as physiotherapists might introduce respective tools in their patient education programmes [14] and (3) treatment success may be optimised using short screenings, such as the Avoidance-Endurance Fast Screen (AE-FS) [15], providing education in an individually tailored manner.