{
  "resourceType": "ActivityDefinition",
  "id": "couch-stretch",
  "url": "https://bodyiq.dev/fhir/ActivityDefinition/couch-stretch",
  "version": "1",
  "name": "CouchStretch",
  "title": "Couch Stretch (Rectus Femoris / Hip Flexor)",
  "status": "draft",
  "experimental": true,
  "description": "Half-kneeling with rear foot elevated against a wall or couch. Combines hip extension with knee flexion to maximally stretch the biarticular rectus femoris. Posterior pelvic tilt stretching reduces reactive hip flexor force by 4.85 N·m vs standard stretching. Stretching up to 120 seconds has no negative performance effect.",
  "useContext": [
    {
      "code": {
        "system": "http://terminology.hl7.org/CodeSystem/usage-context-type",
        "code": "user"
      },
      "valueCodeableConcept": {
        "text": "difficulty: intermediate"
      }
    }
  ],
  "topic": [
    {
      "coding": [
        {
          "system": "https://bodyiq.dev/fhir/CodeSystem/exercise",
          "code": "couch-stretch",
          "display": "Couch Stretch (Rectus Femoris / Hip Flexor)"
        }
      ]
    }
  ],
  "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": "30-120 seconds per side, 1-3 sets, 3-5 days/week [Konrad 2021]"
    }
  ],
  "usage": "Evidence: moderate. Posterior pelvic tilt stretching: 4.85 N·m greater reactive hip flexor force reduction vs standard [González-de-la-Flor 2024]",
  "note": [
    {
      "text": "Posterior pelvic tilt first — front of hip lengthens",
      "authorString": "focus:internal"
    },
    {
      "text": "Drive the front knee gently toward the wall",
      "authorString": "focus:external"
    },
    {
      "text": "Lift the chest tall away from the front thigh",
      "authorString": "focus:external"
    },
    {
      "text": "Tailbone tucks under like closing a wallet",
      "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": "Drop the knee-flexion component back to a standard half-kneeling hip-flexor stretch if RF stretch is too intense.",
      "display": "Hip Flexor and Hamstring Stretching",
      "resource": "ActivityDefinition/hip-flexor-hamstring-stretch"
    }
  ],
  "extension": [
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Rectus Femoris"
        },
        {
          "url": "role",
          "valueCode": "primary"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "72226001"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Iliopsoas"
        },
        {
          "url": "role",
          "valueCode": "primary"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "68455001"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Quadriceps Femoris"
        },
        {
          "url": "role",
          "valueCode": "secondary"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "21989003"
          }
        }
      ]
    }
  ]
}