Finally there is hard, diligent practise, a willingness to undergo the pain and toil of practise. There is a large body of knowledge in Tai Chi Chuan and many things that a student can practise. For example, there is pushing hands, form, Zhanzhuang. You can practise this exercise at different heights, high or low,and for different lengths of time, depending on leg strength. It helps in concentrating the mind, understanding relaxation, strengthening the legs, and increasing internal qi.
People train more in the forms.
Qigong is a relatively new term for arts, some of which, are over 2,000 years old. Originally these were called Daoyin breathing techniques or Neigong. If you practise neijiaquan and don't know about training qi, then it is not neijiaquan. Practising Tai Chi Chuan is training for qi. All the movements of Tai Chi Chuan are training for qi.