Scoliosis are "captured", meaning that they are held fast between the ilium bones of the pelvis. Compared to humans, Old World monkeys have far larger erector spinae muscles, which are the muscles which hold the spine steady. These factors make the lumbar spine of most primates less flexible and far less likely to deviate than those of humans. While this may explicitly relate only to lumbar scolioses, it is possible that small imbalances in the lumbar spine could precipitate thoracic problems as well. Scoliosis may be a byproduct of strong selection for bipedalism. For a bipedal stance, a highly mobile, elongated
Neuromechanics of idiopathic scoliosis scoliosis that appear after the age of 10 years, account for 89% of idiopathic scoliosis. From these statistics, it seems that individuals are at highest risk of developing idiopathic scoliosis during adolescence. Because scoliotic people have higher joint laxity compared to non-scoliotic people, they are drawn toward gymnastics but the practice of gymnastics for less than 20 hours training per week does not cause scoliosis. Based on populations that had more than 20 hours training per week, idiopathic scoliosis has been observed among 10% of tennis players, 16% of young swimmers and 24% in professional ballet companies. The exposure of