{
  "$schema": "https://openexercise.org/schema/v0/exercise.json",
  "aliases": [
    {
      "text": "Supine Bent-Knee Iron Cross",
      "kind": "common"
    },
    {
      "text": "Bent-Knee Windshield Wiper",
      "kind": "common"
    },
    {
      "text": "Bent-Knee Trunk Rotation",
      "kind": "common"
    }
  ],
  "anatomy": {
    "muscles": [
      {
        "muscle": "external-oblique",
        "role": "prime-mover"
      },
      {
        "muscle": "internal-oblique",
        "role": "prime-mover"
      },
      {
        "muscle": "erector-spinae",
        "role": "stretched"
      },
      {
        "muscle": "quadratus-lumborum",
        "role": "stretched"
      },
      {
        "muscle": "piriformis",
        "role": "stretched"
      },
      {
        "muscle": "gluteus-medius",
        "role": "stretched"
      }
    ],
    "joints": [
      {
        "joint": "lumbar-spine",
        "actions": [
          "rotation"
        ]
      },
      {
        "joint": "thoracic-spine",
        "actions": [
          "rotation"
        ]
      },
      {
        "joint": "hip",
        "actions": [
          "internal-rotation",
          "external-rotation"
        ]
      }
    ]
  },
  "classification": {
    "modalities": [
      "mobility",
      "flexibility"
    ],
    "movement_patterns": [
      "rotation",
      "mobility-drill"
    ],
    "mechanics": "compound",
    "force": "not-applicable",
    "kinetic_chain": "open",
    "laterality": "alternating",
    "planes": [
      "transverse"
    ],
    "contraction": [
      "dynamic"
    ],
    "level": "beginner"
  },
  "equipment": {
    "optional": [
      "mat"
    ],
    "required": []
  },
  "external_ids": {
    "wger": "1953"
  },
  "id": "oec:bent-knee-iron-cross",
  "instructions": {
    "setup": [
      "Lie flat on your back on an exercise mat.",
      "Extend your arms straight out to your sides at shoulder level with your palms pressed firmly against the floor.",
      "Lift your feet and bend your hips and knees to approximately 90 degrees in a tabletop position."
    ],
    "steps": [
      "Keeping your knees and ankles pinned together, smoothly lower both legs to one side toward the floor.",
      "Maintain contact between both shoulder blades and the floor as your hips and lower torso rotate.",
      "Just before touching the floor, engage your core and obliques to reverse direction and return to the center.",
      "Rotate your knees smoothly to the opposite side to complete one alternating repetition."
    ],
    "breathing": "Inhale as you rotate your legs toward the floor, and exhale through your mouth as your core pulls them back to center.",
    "cues": [
      "Glue your shoulders to the floor",
      "Knees pinned together",
      "Control the descent with your abs"
    ],
    "common_faults": [
      {
        "fault": "Allowing the opposite shoulder to lift off the floor during the twist.",
        "correction": "Limit the rotational range of motion to only as far as you can keep both shoulder blades pinned down."
      },
      {
        "fault": "Separating the knees or letting the legs slide out of position.",
        "correction": "Squeeze the knees and ankles together throughout the entire arc to maintain unified pelvic rotation."
      },
      {
        "fault": "Using ballistic momentum rather than controlled muscular effort.",
        "correction": "Move at a deliberate, controlled tempo, pausing momentarily at the end range before reversing."
      }
    ],
    "safety": {
      "precautions": [
        "Avoid forcing your knees all the way to the floor if you experience sharp lower back or hip discomfort."
      ],
      "spotter": "not-needed"
    }
  },
  "measurement": {
    "load": {
      "convention": "not-applicable",
      "kind": "none"
    },
    "profiles": [
      {
        "required": [
          "reps"
        ],
        "optional": [
          "duration",
          "rpe"
        ]
      }
    ],
    "records": {},
    "reps_counted": "per-side"
  },
  "name": "Bent-Knee Iron Cross",
  "provenance": {
    "generated": [
      "/name",
      "/summary",
      "/classification",
      "/anatomy",
      "/equipment",
      "/measurement",
      "/instructions",
      "/setup"
    ],
    "license": "CC-BY-SA-4.0",
    "review": {
      "status": "machine-generated",
      "model": "gemini-3.8-flash",
      "at": "2026-10-31"
    },
    "sources": [
      {
        "title": "wger: Bent-knee Iron Cross",
        "url": "https://wger.de/en/exercise/1953/view-base",
        "license": "CC-BY-SA-4.0",
        "author": "Pete-E automation"
      }
    ]
  },
  "setup": {
    "position": "supine"
  },
  "status": "active",
  "summary": "A supine dynamic mobility exercise that rotates the bent legs side to side to mobilize the lumbar spine, hips, and lower back."
}