Insights from Indahl et al. (1999) The sacroiliac (SI) joint is often discussed as a source of low back pain — but does it also play an active role in neuromuscular control? A pivotal animal study by Indahl, Kaigle, Reikeras, and Holm, published in the Journal of Spinal Disorders , investigated whether stimulation of the sacroiliac joint could trigger muscular activation in the trunk and hip. Their findings suggest the SI joint is not just a passive structure — it may be part