{
  "resourceType": "ActivityDefinition",
  "id": "split-squat-bulgarian",
  "url": "https://bodyiq.dev/fhir/ActivityDefinition/split-squat-bulgarian",
  "version": "1",
  "name": "SplitSquatBulgarian",
  "title": "Split Squat / Bulgarian Split Squat",
  "status": "draft",
  "experimental": true,
  "description": "Staggered stance squat with rear foot on ground or elevated on bench. RFESS produces BF 76.1% MVIC (vs 62.3% standard), glute med 54.9% MVIC, and H/Q ratio of 0.83 (vs 0.69 standard). ACL-reconstructed limbs show 7.3% lower vGRF, 12.8% reduced knee contribution, and 9.8% increased hip contribution.",
  "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": "split-squat-bulgarian",
          "display": "Split Squat / Bulgarian Split Squat"
        }
      ]
    }
  ],
  "bodySite": [
    {
      "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"
    },
    {
      "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"
    }
  ],
  "kind": "ServiceRequest",
  "dosage": [
    {
      "text": "3×8-12 reps per leg at 60-80% 1RM, 2-3x/week [Mausehund 2019]"
    }
  ],
  "usage": "Evidence: strong. RFESS: BF 76.1% MVIC, glute med 54.9% MVIC, H/Q ratio 0.83 [Mausehund 2019]. Muscle forces scale more with load in split squat vs bilateral squat [Kipp 2022]",
  "note": [
    {
      "text": "Tall trunk, vertical front shin — front-leg quad and glute share the load",
      "authorString": "focus:internal"
    },
    {
      "text": "Lower the back knee toward the floor",
      "authorString": "focus:external"
    },
    {
      "text": "Push the front foot into the floor to stand tall",
      "authorString": "focus:external"
    },
    {
      "text": "Front knee tracks straight over the second toe",
      "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": "successor",
      "label": "3×10 per side with the front knee tracking over the mid-foot",
      "display": "Single-Leg Sit-to-Stand",
      "resource": "ActivityDefinition/single-leg-sit-to-stand"
    },
    {
      "type": "predecessor",
      "label": "The knee collapses inward, or depth is lost across a set",
      "display": "Squat",
      "resource": "ActivityDefinition/squat"
    }
  ],
  "extension": [
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Quadriceps Femoris"
        },
        {
          "url": "role",
          "valueCode": "primary"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "21989003"
          }
        }
      ]
    },
    {
      "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": "secondary"
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Gluteus Medius"
        },
        {
          "url": "role",
          "valueCode": "stabilizer"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "78333006"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Iliopsoas"
        },
        {
          "url": "role",
          "valueCode": "lengthening"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "68455001"
          }
        }
      ]
    },
    {
      "url": "https://bodyiq.dev/fhir/StructureDefinition/muscle-involvement",
      "extension": [
        {
          "url": "muscle",
          "valueString": "Rectus Femoris"
        },
        {
          "url": "role",
          "valueCode": "lengthening"
        },
        {
          "url": "coding",
          "valueCoding": {
            "system": "http://snomed.info/sct",
            "code": "72226001"
          }
        }
      ]
    }
  ]
}