"ninja gym" meaning in English

{
  "etymology_text": "From this style of obstacles being popularized by the Japanese aerobic sport competition obstacle course racing game show SASUKE which uses a ninja as its logo mascot. From the show being popularized in the English-speaking world as \"Ninja Warrior\" and having spin-offs across the world with variations on the name \"Ninja Warrior\". From competitors calling themselves \"ninja\", and building their own gyms for training, leading to businesses independent of the TV shows having such set-ups, and calling themselves ninja gyms.",
  "forms": [
    {
      "form": "ninja gyms",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ninja gym (plural ninja gyms)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A gym for obstacle course racing training, filled with NinjaWarrior/Sasuke-style obstacles as its exercise equipment."
      ],
      "id": "en-ninja_gym-en-noun-KB8zUY9C",
      "links": [
        [
          "gym",
          "gym#English"
        ],
        [
          "obstacle course",
          "obstacle course#English"
        ],
        [
          "training",
          "training#English"
        ]
      ],
      "related": [
        {
          "word": "ninja show"
        },
        {
          "word": "ninja tour"
        }
      ]
    }
  ],
  "word": "ninja gym"
}

{
  "etymology_text": "From this style of obstacles being popularized by the Japanese aerobic sport competition obstacle course racing game show SASUKE which uses a ninja as its logo mascot. From the show being popularized in the English-speaking world as \"Ninja Warrior\" and having spin-offs across the world with variations on the name \"Ninja Warrior\". From competitors calling themselves \"ninja\", and building their own gyms for training, leading to businesses independent of the TV shows having such set-ups, and calling themselves ninja gyms.",
  "forms": [
    {
      "form": "ninja gyms",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ninja gym (plural ninja gyms)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "ninja show"
    },
    {
      "word": "ninja tour"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns"
      ],
      "glosses": [
        "A gym for obstacle course racing training, filled with NinjaWarrior/Sasuke-style obstacles as its exercise equipment."
      ],
      "links": [
        [
          "gym",
          "gym#English"
        ],
        [
          "obstacle course",
          "obstacle course#English"
        ],
        [
          "training",
          "training#English"
        ]
      ]
    }
  ],
  "word": "ninja gym"
}