Viniyoga is not so much a style as it is a methodology for developing practices for individual conditions and purposes. This is the approach developed by Sri. T. Krishnamacharya, teacher of well-known contemporary masters B.K.S. Iyengar, K. Pattabhi Jois and Indra Devi, and continued by his son, T.K.V. Desikachar. Key characteristic of the asana practice are the careful integration of the flow of breath with movement of the spine, with sequencing, adaptations and intensity dependent upon the overall context and goals. Function is stressed over form. Practices may also include pranayama, meditation, reflection, study and other classic elements. Personal practices are taught privately. Given the scope of practice, the inherent therapeutic applications and the heritage of the lineage, the training requirements for teacher certification are extensive.