{
  "resourceType": "ActivityDefinition",
  "id": "bodyweight-hip-hinge",
  "url": "https://bodyiq.dev/fhir/ActivityDefinition/bodyweight-hip-hinge",
  "version": "1",
  "name": "BodyweightHipHinge",
  "title": "Bodyweight Hip Hinge",
  "status": "draft",
  "experimental": true,
  "description": "Standing hip-dominant bend performed with bodyweight only, optionally holding a broomstick vertically against the spine (touching the back of the head, mid-back, and tailbone) as a tactile cue for maintaining a neutral spine while the hips travel backward.",
  "useContext": [
    {
      "code": {
        "system": "http://terminology.hl7.org/CodeSystem/usage-context-type",
        "code": "user"
      },
      "valueCodeableConcept": {
        "text": "difficulty: beginner"
      }
    }
  ],
  "topic": [
    {
      "coding": [
        {
          "system": "https://bodyiq.dev/fhir/CodeSystem/exercise",
          "code": "bodyweight-hip-hinge",
          "display": "Bodyweight Hip Hinge"
        }
      ]
    }
  ],
  "bodySite": [
    {
      "coding": [
        {
          "system": "https://bodyiq.dev/fhir/CodeSystem/exercise",
          "code": "hip",
          "display": "Hip"
        },
        {
          "system": "http://snomed.info/sct",
          "code": "24136001",
          "display": "Structure of hip joint"
        }
      ],
      "text": "Hip"
    },
    {
      "coding": [
        {
          "system": "https://bodyiq.dev/fhir/CodeSystem/exercise",
          "code": "knee",
          "display": "Knee"
        },
        {
          "system": "http://snomed.info/sct",
          "code": "129159008",
          "display": "Structure of femorotibial joint"
        }
      ],
      "text": "Knee"
    }
  ],
  "kind": "ServiceRequest",
  "dosage": [
    {
      "text": "2-3 sets of 8-12 controlled reps, 3-4 days/week; focus on quality of the neutral-spine pattern rather than fatigue. A 2-3 second lowering (eccentric) phase reinforces motor control."
    }
  ],
  "usage": "Evidence: moderate. Hip-dominant hinging preferentially recruits gluteus maximus and the hamstring group as prime movers while the erector spinae and multifidus act isometrically to hold a neutral spine; deeper hinge angles increase posterior-chain (hamstring/glute) activation relative to a squat pattern.",
  "note": [
    {
      "text": "Push your hips straight back toward the wall behind you and let your chest tip forward like a drawbridge — this is a hinge, not a squat, so the knees only bend slightly."
    },
    {
      "text": "Hold a broomstick vertically along your spine so it touches the back of your head, your mid-back, and your tailbone; keep all three contact points on the stick the entire time to guarantee a neutral spine."
    },
    {
      "text": "Keep your weight in your heels and feel a gentle stretch build in the back of your thighs as you lower — stop hinging when you feel that stretch or your spine starts to round."
    },
    {
      "text": "Stand back up by squeezing your glutes and driving your hips forward to a tall finish; don't lean back or arch your low back at the top."
    }
  ],
  "relatedArtifact": [
    {
      "type": "successor",
      "label": "3×10 hinges to mid-shin with a neutral lumbar spine held throughout",
      "display": "Romanian Deadlift",
      "resource": "ActivityDefinition/romanian-deadlift"
    }
  ],
  "extension": [
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Gluteus Maximus"
        },
        {
          "url": "role",
          "valueCode": "primary"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "206007"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Hamstrings (Group)"
        },
        {
          "url": "role",
          "valueCode": "primary"
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Adductor Magnus"
        },
        {
          "url": "role",
          "valueCode": "synergist"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "23087007"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Erector Spinae Group"
        },
        {
          "url": "role",
          "valueCode": "stabilizer"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "44947003"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Multifidus"
        },
        {
          "url": "role",
          "valueCode": "stabilizer"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "5709001"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Quadratus Lumborum"
        },
        {
          "url": "role",
          "valueCode": "stabilizer"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "6001004"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Transversus Abdominis"
        },
        {
          "url": "role",
          "valueCode": "stabilizer"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "86493009"
          }
        }
      ]
    }
  ]
}