Personal Training (abhyasa) and Detachment (Vairagya) are the foundation of Yoga. A balanced state of the two in our life is the key to personal fulfillment. This means to never give up and to always let go (emotions or negative and past impressions).
Personal Training involves developing great conviction, a constant effort of personal practice in every action, speech and thoughts.
Detachment involves learning to actively explore the self and let go of a lot of attachments (from the material to the emotional one), our fears, and false identities that are clouding the self.
As Patanjali explains, the two work together : the Personal Training or else the Practice leads us in the right direction, and our detachment capacity allows us to continue our journey without being distracted by either the sorrows of life nor its pleasures.
The Personal Training and Detachment are two strong aspects of personality that define a true Yogi. It is by practicing specific techniques we develop these qualities or master it.