{
  "resourceType": "ActivityDefinition",
  "id": "mcgill-curl-up",
  "url": "https://bodyiq.dev/fhir/ActivityDefinition/mcgill-curl-up",
  "version": "1",
  "name": "McgillCurlUp",
  "title": "McGill Curl-Up",
  "status": "draft",
  "experimental": true,
  "description": "Modified curl-up with hands under lumbar spine to maintain lordosis, one knee bent, one straight. Minimal spinal flexion range. Produces RA 50% MVIC while minimizing spinal compression. Partial curl-ups generate the highest muscle challenge-to-spine cost index, optimizing abdominal activation while minimizing spinal loading.",
  "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": "mcgill-curl-up",
          "display": "McGill Curl-Up"
        }
      ]
    }
  ],
  "bodySite": [
    {
      "coding": [
        {
          "system": "https://bodyiq.dev/fhir/CodeSystem/exercise",
          "code": "lumbar-spine",
          "display": "Lumbar Spine"
        },
        {
          "system": "http://snomed.info/sct",
          "code": "23526008",
          "display": "Structure of lumbar intervertebral disc"
        }
      ],
      "text": "Lumbar Spine"
    }
  ],
  "kind": "ServiceRequest",
  "dosage": [
    {
      "text": "3×8-10 reps; focus on quality over quantity — minimal spinal flexion"
    }
  ],
  "usage": "Evidence: strong. RA 48-50% nEMG [Calatayud 2019]. Highest muscle challenge-to-spine cost ratio among abdominal exercises [Axler 1997]",
  "note": [
    {
      "text": "Brace the abdominals — lumbar curve stays preserved",
      "authorString": "focus:internal"
    },
    {
      "text": "Lift the head and shoulders just off the surface",
      "authorString": "focus:external"
    },
    {
      "text": "Press the lower back gently into the fingers underneath",
      "authorString": "focus:external"
    },
    {
      "text": "Hands beneath lumbar spine feel the natural curve held",
      "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"
      }
    }
  ],
  "extension": [
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Rectus Abdominis"
        },
        {
          "url": "role",
          "valueCode": "primary"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "31243008"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "External Oblique"
        },
        {
          "url": "role",
          "valueCode": "secondary"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "1179024003"
          }
        }
      ]
    },
    {
      "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"
          }
        }
      ]
    }
  ]
}