Answer to the Letter to the Editor of S. Negrini et al. concerning “Active self-correction and task-oriented exercises reduce spinal deformity and improve quality of life in subjects with mild adolescent idiopathic scoliosis. Results of a randomised controlled trial” by Monticone M, Ambrosini E, Cazzaniga D, Rocca B, Ferrante S (2014) Eur Spine J; DOI 10.1007/s00586-014-3241-y