{
  "resourceType": "ActivityDefinition",
  "id": "supine-chin-tuck-liftoff",
  "url": "https://bodyiq.dev/fhir/ActivityDefinition/supine-chin-tuck-liftoff",
  "version": "1",
  "name": "SupineChinTuckLiftoff",
  "title": "Supine Chin Tuck with Liftoff",
  "status": "draft",
  "experimental": true,
  "description": "Deep cervical flexor endurance exercise. Patient lies supine, performs a chin tuck (craniocervical flexion), then lifts the head slightly off the surface maintaining the tucked position. Targets longus colli/capitis endurance with minimal sternocleidomastoid activation. Normative hold times: men 38.9±20.1s, women 29.4±13.7s.",
  "useContext": [
    {
      "code": {
        "system": "http://terminology.hl7.org/CodeSystem/usage-context-type",
        "code": "user"
      },
      "valueCodeableConcept": {
        "text": "difficulty: beginner-intermediate"
      }
    }
  ],
  "topic": [
    {
      "coding": [
        {
          "system": "https://bodyiq.dev/fhir/CodeSystem/exercise",
          "code": "supine-chin-tuck-liftoff",
          "display": "Supine Chin Tuck with Liftoff"
        }
      ]
    }
  ],
  "bodySite": [
    {
      "coding": [
        {
          "system": "https://bodyiq.dev/fhir/CodeSystem/exercise",
          "code": "cervical-spine",
          "display": "Cervical Spine"
        },
        {
          "system": "http://snomed.info/sct",
          "code": "20292002",
          "display": "Structure of atlantooccipital joint"
        },
        {
          "system": "http://snomed.info/sct",
          "code": "68818006",
          "display": "Structure of cervical intervertebral disc"
        }
      ],
      "text": "Cervical Spine"
    }
  ],
  "kind": "ServiceRequest",
  "dosage": [
    {
      "text": "5-10 reps × 10s holds, progress hold duration toward normative values, 2-3x/week"
    }
  ],
  "usage": "Evidence: strong. CCF pattern activates deep cervical flexors (longus colli/capitis) with significantly less SCM activation than head-lift alone [O'Leary 2007]. Target hold: men ~39s, women ~29s [Domenech 2011].",
  "note": [
    {
      "text": "Soft chin tuck before the head leaves the surface",
      "authorString": "focus:internal"
    },
    {
      "text": "Float the head a card's thickness off the floor",
      "authorString": "focus:external"
    },
    {
      "text": "Hold the feather-light lift for 10 seconds",
      "authorString": "focus:external"
    },
    {
      "text": "Front of throat stays soft — palpate to confirm",
      "authorString": "focus:tactile"
    }
  ],
  "relatedArtifact": [
    {
      "type": "citation",
      "label": "kisner-therapeutic-2017",
      "citation": "Kisner C, Colby LA, Borstad J. (2017). Therapeutic Exercise: Foundations and Techniques"
    },
    {
      "type": "citation",
      "label": "acsm-guidelines-2021",
      "citation": "American College of Sports Medicine. (2021). ACSM's Guidelines for Exercise Testing and Prescription",
      "document": {
        "url": "https://doi.org/10.4135/9781412994149.n165"
      }
    },
    {
      "type": "predecessor",
      "label": "If the patient cannot maintain the tuck during liftoff or substitutes SCM, drop to the pure CCF pattern; the liftoff's named 'Chin Tuck Without Liftoff' regression IS the deep-neck-flexor-training CCF node. Distinct roster nodes.",
      "display": "Deep Neck Flexor Training (Chin Tucks with Pressure Biofeedback)",
      "resource": "ActivityDefinition/deep-neck-flexor-training"
    }
  ],
  "extension": [
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Deep Cervical Flexors"
        },
        {
          "url": "role",
          "valueCode": "primary"
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Sternocleidomastoid"
        },
        {
          "url": "role",
          "valueCode": "synergist"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "22823000"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Scalene Muscles"
        },
        {
          "url": "role",
          "valueCode": "stabilizer"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "50755001"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Semispinalis Capitis"
        },
        {
          "url": "role",
          "valueCode": "lengthening"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "2666009"
          }
        }
      ]
    }
  ]
}