Personal growth can have different scales: it can be improvements within the personal norm, or it can be a way out of it.
The man was sick, gradually recovered and returned to normal. In a psychological metaphor, this is not personal growth, but recovery, successful psychotherapy. A healthy person went to fitness and removed his tummy: in a metaphor, this is personal growth, but within the norm. He is among the best, but still not an athlete. If a person went in for sports and began to stand out significantly in terms of indicators, became different from the majority, in a metaphor this is personal growth that rises above the norm.
When there are personal, and not just physical changes in a person, then changes within the personal norm are a small personal growth. He was a categorical, quick-tempered, touchy person, did not feel a partner — when he eliminated these shortcomings and became quite decent, he experienced personal growth. But he remained within the majority, he remained among the many.
As a rule, such small personal growth occurs in parallel with the process of Gestalt therapy and similar systems, see Containment Techniques. In psychological terms, it is more accurate to talk about psychocorrection, in pedagogical terms it is education or self-education.
If he has acquired leadership qualities, learned to work with himself independently, has acquired invulnerability from the blows of life, if he is guaranteed to be protected from depression and alcoholism, if this has become in principle incompatible with his way of life — it seems that such features of him are distinguished from the normative majority, this going beyond the norm is a great personal growth.
As a rule, great personal growth in itself, just as growth, does not occur, such results usually occur as a result of personality development. In pedagogical terms, this is self-improvement.