This study showed that there was no difference in self-perceived functional ability between women with long-term back pain and those without long-term back pain, although those with pain did poorer in all performance-based tests of physical function. The women with long-term back pain also perceived themselves as less physically fit compared to those without pain. The discrepancy between self-perceived ability and objectively observed function may have several reasons [
27]. Kamitani et al. (2019) found that the discrepancy between high performance-based measurements and low self-reported physical functioning level is associated with an increased risk of future falls in older adults [
28]. It is worth considering that the reverse conditions, i.e., low performance-based measurements and high self-reported physical functioning and could also be an indicator of an increased risk of falls in that the person becomes overconfident in her abilities, resulting in carelessness in physical activities. In the study by Kamitani et al. (2019), there were both male and female participants, and it might be worth considering the possibility that there might be a difference between male and female self-reported physical functioning based on gender-labeled traits and preconceptions [
28]. It has also been reported that older women tend to both overestimate and underestimate limitations, especially in upper body functions, but the extent to which this could explain discrepancies needs to be further investigated [
29]. Beauchamp and colleagues [
30] have shown a comparable psychometric property between an interview-administered questionnaire and standardized performance-based measurements, such as gait speed and a 400-m walk and stair climb power test, suggesting the validity of using either of the measurement procedures. Subjective measures may be inaccurate because a person may overestimate or underestimate her capabilities for various reasons. Although objective measurements, such as performance-based tests, can be standardized and objectively scored, they are neither superior to nor interchangeable with subjective measures [
31,
32]. Walking speed, for example, has a well-documented predictive value for major health-related outcomes such as hospitalizations, nursing home placements, mortality, poor quality of life, physical and cognitive functional decline, and falls [
33]. Assessment of physical function can be of importance both from the perspective of identifying older adults at risk of such events and identifying resources crucial to successful rehabilitation and care [
34]. Self-reported outcome measurements provide a person’s perception of her ability and therefore depict a more person-centered assessment, with the potential to estimate the impact on the person’s daily life. On the other hand, the standardized performance-based measurements capture a more objective picture of the current status and might therefore be seen as being a more valid and sensitive estimate of change [
19,
29]. According to our knowledge, research is lacking about older women with long-term back pain and how they perceive their ability. In the present study, the women living with long-term back pain reported that they managed and the women without long-term back pain in terms of walking indoors and outdoors, bending down, or any restriction within their home environment in their immediate surroundings. Also, there were no differences between the groups in self-reported ADL and IADL. One important distinction between the use of self-reported outcome measurements and the standardized performance-based test is that the self-reported assessments provide a broad array of functional abilities that are significant for older individuals, while the performance-based tests produce results for a limited number of abilities, such as walking speed and chair standing [
33,
34]. This raises the question of what is important within their socio-cultural context and, as a result, what they use in their everyday life and have reason to value. The authors underline the fact that the choice of measurement strategies must be guided by the research question of interest, the complexity and the nature of the data, as well as an awareness that different clinical settings, populations, conditions (e.g., pain, depression, and fear of falling) and contexts are thought to affect the measurements [
27,
34]. The use of both performance-based tests of physical function and self-reported functional ability level would create opportunities to identify discrepancies and therefore be able to establish prerequisites for person-centered practice in future care needs [
35]. It can be argued that, by assessing both subjective and objective ability, health-care providers might be able both to develop more effective fall prevention plans and to improve the subjective level of assessment, as well as being able to identify persons at risk of adverse events such as injuring falls and early signs of functional decline [
28,
34]. This could then lay the foundations for person-centered practice, which, according to the literature, might empower individuals to manage their life situation [
35], reinforce and strengthen a sense of security to enhance their quality of life, and continue being resilient, resourceful, and confident in order to find new ways of managing their future everyday life [
11,
22,
36,
37].