Atta-kilamatha: Self-mortification = self-torture, is one of the two extremes to be avoided, the other extreme being addiction to sensual pleasures kāma - sukha, whilst the Noble 8-fold path constitutes the Middle path majjhima - patipadā. See the Buddha’s first sermon, The Establishment of the Realm of Dhamma: Dhamma-cakkappavattana-Sutta.