{
  "$schema": "https://openexercise.org/schema/v0/exercise.json",
  "aliases": [
    {
      "text": "Behind-the-Back Deadlift",
      "kind": "common"
    },
    {
      "text": "Hackenschmidt Squat",
      "kind": "common"
    },
    {
      "text": "Rear Deadlift",
      "kind": "common"
    },
    {
      "text": "Barbell Hack Squats",
      "kind": "common"
    }
  ],
  "anatomy": {
    "muscles": [
      {
        "muscle": "quadriceps",
        "role": "prime-mover"
      },
      {
        "muscle": "gluteus-maximus",
        "role": "synergist"
      },
      {
        "muscle": "adductor-magnus",
        "role": "synergist"
      },
      {
        "muscle": "soleus",
        "role": "synergist"
      },
      {
        "muscle": "forearm-flexors",
        "role": "stabilizer"
      },
      {
        "muscle": "erector-spinae",
        "role": "stabilizer"
      },
      {
        "muscle": "trapezius-upper",
        "role": "stabilizer"
      }
    ],
    "joints": [
      {
        "joint": "knee",
        "actions": [
          "extension",
          "flexion"
        ]
      },
      {
        "joint": "hip",
        "actions": [
          "extension",
          "flexion"
        ]
      },
      {
        "joint": "ankle",
        "actions": [
          "plantarflexion",
          "dorsiflexion"
        ]
      },
      {
        "joint": "lumbar-spine",
        "actions": [
          "isometric-stabilization"
        ]
      },
      {
        "joint": "fingers",
        "actions": [
          "isometric-stabilization"
        ]
      }
    ]
  },
  "classification": {
    "modalities": [
      "strength",
      "hypertrophy"
    ],
    "movement_patterns": [
      "squat"
    ],
    "mechanics": "compound",
    "force": "push",
    "kinetic_chain": "closed",
    "laterality": "bilateral",
    "planes": [
      "sagittal"
    ],
    "contraction": [
      "dynamic"
    ],
    "level": "intermediate"
  },
  "equipment": {
    "optional": [
      "weight-plate"
    ],
    "required": [
      [
        "barbell"
      ]
    ]
  },
  "external_ids": {
    "wger": "43"
  },
  "id": "oec:barbell-hack-squat",
  "instructions": {
    "setup": [
      "Place a loaded barbell on the floor directly behind your heels.",
      "Stand with your feet hip-width apart, toes pointing forward or slightly outward.",
      "Squat down by flexing your knees and hips while maintaining an upright torso until your hands reach the bar behind your legs.",
      "Grip the barbell with a shoulder-width pronated grip (palms facing backward), depress your shoulders, and brace your core."
    ],
    "steps": [
      "Drive through your midfoot and heels, pushing the floor away to extend your knees and hips simultaneously.",
      "Keep your torso as upright as possible as the bar slides up along the backs of your calves and thighs.",
      "Stand fully erect, locking out your hips and knees at the top without hyperextending your lower back.",
      "Controlledly descend by bending at the knees and hips, guiding the bar back down behind your legs until the plates touch the floor."
    ],
    "breathing": "Inhale and brace your core before descending or breaking the bar off the floor, holding tension through the lift and exhaling as you complete the lockout.",
    "cues": [
      "Stay upright and push the floor away.",
      "Drive your knees forward over your toes.",
      "Keep your chest proud and arms fully straight."
    ],
    "common_faults": [
      {
        "fault": "Excessive forward torso lean turning the movement into a stiff-legged deadlift.",
        "correction": "Elevate your heels slightly on small plates if needed and focus on bending deeply at the knees to keep your torso upright."
      },
      {
        "fault": "Letting the bar drift away from the backs of your legs.",
        "correction": "Keep the bar in close proximity to your calves and hamstrings throughout the ascent and descent."
      },
      {
        "fault": "Bending the elbows to pull the weight up.",
        "correction": "Keep your arms completely straight like ropes and let your leg drive lift the barbell."
      }
    ],
    "safety": {
      "precautions": [
        "Ensure your grip is secure and use lifting straps if your grip fails before your quadriceps.",
        "Do not allow your lumbar spine to round into flexion at the bottom of the lift."
      ],
      "spotter": "not-needed"
    }
  },
  "measurement": {
    "load": {
      "convention": "total",
      "implements": 1,
      "kind": "external"
    },
    "profiles": [
      {
        "required": [
          "reps",
          "load"
        ],
        "optional": [
          "rpe"
        ]
      }
    ],
    "records": {
      "e1rm": true,
      "volume": true
    },
    "reps_counted": "total"
  },
  "name": "Barbell Hack Squat",
  "previous_ids": [
    "oec:barbell-hack-squats"
  ],
  "provenance": {
    "generated": [
      "/name",
      "/summary",
      "/classification",
      "/anatomy",
      "/equipment",
      "/measurement",
      "/instructions",
      "/setup",
      "/relations"
    ],
    "license": "CC-BY-SA-4.0",
    "review": {
      "status": "machine-generated",
      "model": "gemini-3.8-flash",
      "at": "2026-10-31"
    },
    "sources": [
      {
        "title": "wger: Barbell Hack Squats",
        "url": "https://wger.de/en/exercise/43/view-base",
        "license": "CC-BY-SA-4.0",
        "author": "BePieToday"
      }
    ]
  },
  "relations": [
    {
      "type": "substitute-for",
      "target": "oec:hack-squat"
    },
    {
      "type": "substitute-for",
      "target": "oec:machine-hack-squat"
    },
    {
      "type": "variation-of",
      "target": "oec:barbell-back-squat"
    }
  ],
  "setup": {
    "grip": {
      "orientation": "pronated",
      "width": "shoulder"
    },
    "load_position": "at-sides",
    "position": "standing",
    "range": "full",
    "stance": {
      "kind": "parallel",
      "width": "hip"
    }
  },
  "status": "active",
  "summary": "A classic squat variation where a barbell is lifted from the floor behind the calves, placing high mechanical demand on the quadriceps."
}