What does スポ根 Spokon mean?

Spokon is the sports story built on willpower. The name is a blend of the loanword for sports and 根性 (konjou), which means guts, grit, or the capacity to keep going when there is no reason to.

The second half is the genre

Sports supplies the setting. The other element supplies the subject, and the subject is not athletic achievement. It is what a person will endure, and whether enduring it produces anything.

Which is why training sequences dominate these stories while matches are often brief. A tournament result is the receipt; the training is the transaction.

Where it comes from

The genre is usually dated to the mid 1960s, with a baseball manga by Ikki Kajiwara beginning in 1966 as the founding case, and a boxing story from the same writer following as the other pillar.

The timing is not incidental. These are stories about improvement through relentless effort, arriving for a young audience in a decade when material conditions for many were hard and the promise that effort compounds had obvious appeal.

The part that has aged

The coaching. Classic examples feature training regimes that are frankly abusive, presented as necessary and administered by adults the story approves of, and modern readers notice.

Japanese sports culture has had its own long reckoning with exactly this, and contemporary sports manga frequently reads as an argument with the older form: coaches who are competent rather than cruel, and improvement through method rather than through punishment.

Why the word still matters

Because it names the thing later works are reacting against. A modern volleyball or cycling story is legible partly as a correction, and the correction only reads if the original position has a name.

English says sports anime, which describes the shelf. This describes the argument, and the argument is what the genre was actually about.