That manga is a typical gutsy sports story.
His training regimen is the epitome of fighting spirit.
Standard abbreviation of スポーツ根性. This is the most common written form.
Irregular kanji usage replacing 根 with 魂 (spirit/soul). Occasionally seen for stylistic effect.
A contraction of スポーツ根性, combining the opening of スポーツ with 根, the first character of 根性.