Yoga is a very tricky word indeed. On one hand it relates to Philosophy with seemingly theoretical ideas. The nature of the theoretical ideas is to explain the phenomenon to achieve an abstract status of the total removal of sorrow through Nirbeeja Samadhi followed by Kaivalya. But, an important feature of the Indian Philosophy is to actualize the abstract into one’s life, a status called Self Realization or Enlightenment. This puts Indian Philosophy different from all other philosophies. (That is why Yoga has a direct association with Hinduism, which is a Philosophy and NOT a religion).
Therefore, Yoga provides actual practice that facilitates one to arrive at the above described status. In this manner, all types of Yoga, whether Karma Yoga, Jnana Yoga, Bhakti Yoga or Raja Yoga, has definite practical side. And, this side has been an innate nature of Yoga, and not that it was added later after the theory of Yoga has been established first.
Therefore, anyone trying to understand Yoga Philosophy without performing sufficient practice is likely to slip from the understanding. And, anyone who tries to practice limited practices without expanding the philosophical horizon is going to develop insufficient understanding of Yoga.