Thirty-three patients with low back pain or sacroiliac joint pain were included in this crossover randomized trial assessing the effect of a Serola Sacroiliac belt on pain and functional impairment after 5 days of strenuous repeated manual labour. Patients either performed 5 days of manual labour tasks with the belt followed by 5 days of manual labour tasks without, or vice-versa. Outcomes of interest included Numeric Rating Scale (NRS) pain scores, spine and thigh discomfort on a Nordic Musculoskeletal Questionnaire (NMQ), and flexion relaxation phenomenon testing, measured after the completion of each intervention period. Whilst both groups demonstrated progression in symptoms, the results found that Serola belt usage resulted in less progression of NRS back pain compared to the control group. No other differences were observed.