{
  "$schema": "https://openexercise.org/schema/v0/exercise.json",
  "aliases": [
    {
      "text": "Hack Squat",
      "kind": "common"
    },
    {
      "text": "Hackenschmidt Squat",
      "kind": "common"
    },
    {
      "text": "Leg Press on Hackenschmidt Machine",
      "kind": "misspelling"
    },
    {
      "text": "Sled Hack Squat",
      "kind": "common"
    }
  ],
  "anatomy": {
    "muscles": [
      {
        "muscle": "quadriceps",
        "role": "prime-mover"
      },
      {
        "muscle": "gluteus-maximus",
        "role": "synergist"
      },
      {
        "muscle": "adductor-magnus",
        "role": "synergist"
      },
      {
        "muscle": "soleus",
        "role": "synergist"
      },
      {
        "muscle": "gastrocnemius",
        "role": "stabilizer"
      },
      {
        "muscle": "rectus-abdominis",
        "role": "stabilizer"
      }
    ],
    "joints": [
      {
        "joint": "knee",
        "actions": [
          "extension",
          "flexion"
        ]
      },
      {
        "joint": "hip",
        "actions": [
          "extension",
          "flexion"
        ]
      },
      {
        "joint": "ankle",
        "actions": [
          "plantarflexion",
          "dorsiflexion"
        ]
      }
    ]
  },
  "classification": {
    "modalities": [
      "hypertrophy",
      "strength"
    ],
    "movement_patterns": [
      "squat"
    ],
    "mechanics": "compound",
    "force": "push",
    "kinetic_chain": "closed",
    "laterality": "bilateral",
    "planes": [
      "sagittal"
    ],
    "contraction": [
      "dynamic"
    ],
    "level": "intermediate"
  },
  "equipment": {
    "required": [
      [
        "hack-squat-machine"
      ]
    ]
  },
  "external_ids": {
    "wger": "375"
  },
  "id": "oec:machine-hack-squat",
  "instructions": {
    "setup": [
      "Position your back and head firmly against the angled back pad with your shoulders positioned snugly under the shoulder pads.",
      "Place your feet on the platform roughly shoulder-width apart, with toes angled slightly outward.",
      "Extend your legs to lift the carriage off the stops and disengage the safety release handles."
    ],
    "steps": [
      "Inhale, brace your core, and smoothly lower the carriage by bending your knees and hips.",
      "Descend until your thighs reach at least parallel to the footplate, or as deep as your hip mobility allows without your lower back rounding off the pad.",
      "Drive through your whole foot, extending your knees and hips to return to the starting position without forcefully hyperextending your knees at the top."
    ],
    "breathing": "Inhale and brace your core during the descent, and exhale forcefully as you drive through the sticking point on the ascent.",
    "cues": [
      "Keep lower back glued to the pad",
      "Drive through the midfoot and heel",
      "Track knees in line with toes"
    ],
    "common_faults": [
      {
        "fault": "Allowing the lower back or pelvis to lift off the back pad at the bottom of the movement.",
        "correction": "Limit the depth of the squat to what your active mobility allows and keep the pelvis anchored against the pad."
      },
      {
        "fault": "Lifting the heels off the footplate during the descent.",
        "correction": "Move your feet slightly higher on the platform or focus on driving pressure through the whole foot."
      },
      {
        "fault": "Violently locking out the knees at the top of each rep.",
        "correction": "Stop just short of complete knee hyperextension to keep continuous tension on the quadriceps and protect the joint."
      }
    ],
    "safety": {
      "precautions": [
        "Ensure the safety catches are properly set to prevent the sled from bottoming out dangerously in case of muscle failure.",
        "Re-engage the safety catch handles before stepping out of the machine."
      ],
      "spotter": "not-needed",
      "safeties": true
    }
  },
  "measurement": {
    "load": {
      "convention": "total",
      "implements": 1,
      "kind": "external"
    },
    "profiles": [
      {
        "required": [
          "reps",
          "load"
        ],
        "optional": [
          "rpe"
        ]
      }
    ],
    "records": {
      "e1rm": true,
      "volume": true
    },
    "reps_counted": "total"
  },
  "name": "Machine Hack Squat",
  "previous_ids": [
    "oec:leg-press-on-hackenschmidt-machine"
  ],
  "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: Leg Press on Hackenschmidt Machine",
        "url": "https://wger.de/en/exercise/375/view-base",
        "license": "CC-BY-SA-3.0",
        "author": "wger.de"
      }
    ]
  },
  "relations": [
    {
      "type": "variation-of",
      "target": "oec:hack-squat"
    },
    {
      "type": "substitute-for",
      "target": "oec:barbell-hack-squat"
    },
    {
      "type": "substitute-for",
      "target": "oec:leg-press"
    }
  ],
  "setup": {
    "load_position": "back",
    "position": "standing",
    "range": "full",
    "stance": {
      "kind": "parallel",
      "width": "shoulder"
    }
  },
  "status": "active",
  "summary": "A machine-based squat variation performed on an angled sled with shoulder pads and back support, heavily loading the quadriceps."
}