Leg Extension

Muscles worked by the Leg Extension

Primary

QuadsQuadriceps Femoris

Also called: quad, quads, quadriceps, quadriceps femoris, front thigh.

Equipment

Leg Extension

Also called: leg extension machine, quad extension, knee extension.

How to do the Leg Extension

1. Sit in the leg extension machine with ankles behind the pad.
2. Extend your legs until they are straight.
3. Squeeze your quads at the top.
4. Lower with control.
5. Repeat.

Form tips

• Adjust the seat so your knees align with the machine's pivot point.
• Keep your back pressed against the pad throughout.
• Avoid swinging the weight up with momentum.

At a glance

Leg Extension in German & Spanish

Descriptions, instructions and tips ship in all three languages in the JSON.

Related exercises

• Barbell Back Squat
• Barbell Lunge
• Barbell Reverse Lunge
• Bench Bulgarian Split Stretch
• Bench Couch Stretch
• Bodyweight Squat
• Box Jump
• Box Squat

Exercise data (JSON)

The record below is exactly what exercises.json ships for this exercise — names, descriptions, instructions and tips in English, German and Spanish.

{
  "id": "leg-extension",
  "name_en": "Leg Extension",
  "name_de": "Beinstrecker",
  "name_es": "Extensión de Piernas",
  "description_en": "An isolation exercise for the quadriceps using a machine.",
  "description_de": "Eine Isolationsübung für den Quadrizeps am Streckmaschine.",
  "description_es": "Un ejercicio de aislamiento para los cuádriceps usando una máquina.",
  "category": "strength",
  "force_type": "push",
  "mechanic": "isolation",
  "difficulty": "beginner",
  "equipment": "leg_extension",
  "body_part": "upper_legs",
  "primary_muscles": [
    "quadriceps"
  ],
  "goals": [
    "hypertrophy"
  ],
  "tags": [
    "leg_day",
    "lower_back_safe",
    "shoulder_safe",
    "no_axial_load",
    "knee_safe"
  ],
  "variation_group": "leg-extension",
  "is_unilateral": false,
  "is_bodyweight": false,
  "instructions_en": [
    "Sit in the leg extension machine with ankles behind the pad.",
    "Extend your legs until they are straight.",
    "Squeeze your quads at the top.",
    "Lower with control.",
    "Repeat."
  ],
  "instructions_de": [
    "Setze dich in die Beinstreckmaschine mit den Fußknöcheln hinter der Rolle.",
    "Strecke die Beine, bis sie gerade sind.",
    "Spanne den Quadrizeps am höchsten Punkt an.",
    "Senke kontrolliert ab.",
    "Wiederhole."
  ],
  "instructions_es": [
    "Siéntate en la máquina de extensión de piernas con los tobillos detrás del rodillo.",
    "Extiende las piernas hasta que queden rectas.",
    "Aprieta los cuádriceps en la parte superior.",
    "Baja con control.",
    "Repite."
  ],
  "tips_en": [
    "Adjust the seat so your knees align with the machine's pivot point.",
    "Keep your back pressed against the pad throughout.",
    "Avoid swinging the weight up with momentum."
  ],
  "tips_de": [
    "Richte den Sitz so ein, dass deine Knie mit dem Drehpunkt der Maschine fluchten.",
    "Halte den Rücken fest an der Lehne, ohne die Hüfte anzuheben.",
    "Arbeite ohne Schwung und lass das Gewicht nicht auf den Stapel fallen."
  ],
  "tips_es": [
    "Alinea las rodillas con el eje de giro de la máquina.",
    "Sube el peso sin lanzarlo con impulso.",
    "Agárrate a las asas para mantener la cadera estable en el asiento."
  ],
  "met": 5.0,
  "images": {
    "flat": {
      "start": "images/flat/leg-extension-start.webp",
      "peak": "images/flat/leg-extension-peak.webp"
    }
  }
}

Fetch just this exercise

const { exercises } = await fetch(
  "https://exercise-dataset.com/exercises.json"
).then(r => r.json());
const ex = exercises.find(e => e.id === "leg-extension");

Free for personal and commercial in-app use with attribution (“Exercise data by RepDB”) — see the license and ready-made attribution snippets. Redistributing the data as a dataset or API is not permitted.