BACKGROUND AND AIM: NSLBP is characterized by symptoms without clear patho-anatomical causes and cLBP has been identified as one of the leading global causes of disability [1]. The majority of clinical trials assess cNSLBP using scales or questionnaires reporting an influence of cognitive, emotional and behavioral factors [2]. Previous studies have evaluated the motor consequences of cNSLBP using biomechanical analysis, showing alterations in the kinematics and dynamics of locomotion [3,4]. However, few studies have evaluated cNSLBP participants in ecological situations, such as walking with obstacles or avoidance, allowing a simultaneous evaluation of cognitive, perceptual and motor components in a situation closer to the one encountered in daily life. In this context, using a horizontal aperture crossing paradigm [5], this study aimed to 1) understand the effect of cNSLBP in action strategies and (2) identify factors that may influence these decisions. METHODS: Healthy adults (N=15) and cNSLBP adults (N=15) performed a walking protocol composed of 3 random blocks of 19 trials with aperture ranging from 0.9 to 1.8 x shoulder width. The dimensions of the obstacle causing an individual to change their actions (shoulders rotation, velocity, trunk stability) is referred to as the Critical Point (CP). RESULTS: In these preliminary results considering shoulder width, welch's t-test showed that the average CP in the healthy group was significantly larger (1.20 SD = 0.052) than the one of cNSLBP group (1.15, SD = 0.029) (t(20.08) = 3.07, p<0.01, d = 1.16). CONCLUSIONS: This analysis on shoulder data is a first attempt to investigate the influence of cNSLBP on motor behavior and decisions in an ecological paradigm. Results show a slightly more risky behavior of patients with smaller CP. Future work is required to study walking speed profile and to relate behavioral data with variables that can influence pain perception (intensity, duration, kinesiophobia, fear avoidance beliefs, catastrophism and psychological inflexibility). [1] Maher et al. (2017) The Lancet. [2] Chiarotto et al. (2015) European Spine Journal. [3] Koch et al. (2019) Frontiers in psychology. [4] Moissenet et al. (2021) Scientific reports. [5] Higuchi et al. (2006) Experimental Brain Research.