In the front matter of his book, The Science of Yoga, author William Broad, lists 12 distinct ‘schools’ of yoga. By school I mean each teaches a widely-recognized ‘signature’ pattern of postures or sequences and articulates a distinctive approach or philosophy. Those he lists–you’ll recognize most by name if you’re even moderately familiar with yoga–include:

Anusara

Ashtanga

Bikram

Flow

Hatha

Iyengar

Kripalu

Kundalini

Power

Sivananda

Viniyoga

Vinyasa (He also includes Yogafit, but I consider this to be more a brand, than a school, marketed through gyms and health clubs.)

Wikipedia lists about 60 schools of martial arts, including 10 for Japan and 13 for Korea.

In contrast, while people do swimming for competition, fitness or as a lifesaving skill — and there are four ‘approved’ strokes plus a couple of informal styles (sidestroke, dog paddle, elementary backstroke) — there is only one ‘school’ of swimming. I.E. A distinctive ‘signature’ form accompanied by a well-articulated philosophy. That would be . . .  ta dum . . . Total Immersion.

All the rest is just, well, Not-TI.

If any reader can name another approach to swimming with a distinctive form and philosophy, we welcome you to nominate it for recognition as a school of swimming.