Non-specific chronic low back pain (NSCLBP) is a significant public health problem, with increasing prevalence and incidence over the years. Physical exercise is recommended as the first-line treatment, with traditional resistance training widely used for strength and muscle hypertrophy development. The total training volume can be classified as low, medium, or high, directly influencing neuromuscular adaptations. Although evidence suggests that a higher number of sets results in greater adaptations, there are still gaps regarding the minimum necessary dose to optimize strength and hypertrophy gains, especially in individuals with musculoskeletal disorders such as NSCLBP. Furthermore, the ideal prescription of load, intensity, and recovery for this population remains a challenge.

This study aims to analyze the influence of series volume progression (2, 4, and 6 sets) every two weeks on functional capacity, muscle power, and body composition in people with NSCLBP.

This is a randomized clinical trial lasting 12 weeks. The first two weeks will be dedicated to initial assessments and familiarization with the exercises, followed by eight weeks of intervention and, finally, two weeks for final evaluations. Functional capacity will be measured using the Roland-Morris Questionnaire, while muscle power will be assessed through the countermovement jump (CMJ). Lower and upper limb strength will be measured using isokinetic dynamometry, trunk strength through functional tests, and body composition through densitometry (DEXA). The training protocol will include exercises such as stiff-leg deadlift, conventional deadlift, and half-squat, with a progressive increase in the number of sets throughout the intervention. The sample will include individuals of both sexes, aged between 18 and 40 years, with an NSCLBP diagnosis for at least 12 weeks. A total of 33 individuals (11 per group) are expected to participate in the study. The study will be conducted following ethical guidelines and submitted to the Research Ethics Committee.

It is anticipated that all participants will show a reduction in disability associated with NSCLBP, with greater benefits in the groups performing a lower volume of sets.

It is hypothesized that the low- and medium-volume groups will perform better in functional capacity and physical tests compared to the high-volume group, considering guidelines that suggest excessive volumes may not be ideal for this population.

The study's findings are expected to contribute to the development of safe and effective training progression strategies for individuals with NSCLBP, providing scientific support for designing specific programs for this population.