Single Leg Extension

A quadriceps isolation exercise performed on a leg extension machine, working one leg at a time.

Upper legs · Leg Extension · Intermediate

Single Leg Extension — start position, flat illustration — start

Single Leg Extension — peak position, flat illustration — peak

Muscles worked by the Single 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 Single Leg Extension

Sit on a leg extension machine and place one foot under the pad.
Rest the other foot on the floor or let it hang.
Extend the working leg until it is nearly straight.
Squeeze the quadriceps at the top.
Lower the leg back down under control.
Complete reps on one side, then switch.

Form tips

Squeeze the quadriceps hard at the top of the movement.
Lower the weight under control rather than letting it drop.
Keep your back flat against the pad.

At a glance

Body part	Upper legs
Category	Strength
Force type	Push
Mechanic	Isolation
Difficulty	Intermediate
Equipment	Leg Extension
Goals	Hypertrophy
Tags	Lower back safe, Shoulder safe, No axial load, Knee safe
MET	5.0 (metabolic equivalent, for calorie estimates)
Unilateral	Yes
Bodyweight	No
Dataset id	single-leg-extension

Single Leg Extension in German & Spanish

German	Einbeiniges Beinstrecken
Spanish	Extensión de Cuádriceps a Una Pierna

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

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": "single-leg-extension",
  "name_en": "Single Leg Extension",
  "name_de": "Einbeiniges Beinstrecken",
  "name_es": "Extensión de Cuádriceps a Una Pierna",
  "description_en": "A quadriceps isolation exercise performed on a leg extension machine, working one leg at a time.",
  "description_de": "Eine Quadrizeps-Isolationsübung an der Beinstreckermaschine, bei der abwechselnd ein Bein trainiert wird.",
  "description_es": "Un ejercicio de aislamiento de cuádriceps en una máquina de extensión de piernas, trabajando una pierna a la vez.",
  "category": "strength",
  "force_type": "push",
  "mechanic": "isolation",
  "difficulty": "intermediate",
  "equipment": "leg_extension",
  "body_part": "upper_legs",
  "primary_muscles": [
    "quadriceps"
  ],
  "goals": [
    "hypertrophy"
  ],
  "tags": [
    "lower_back_safe",
    "shoulder_safe",
    "no_axial_load",
    "knee_safe"
  ],
  "variation_group": "leg-extension",
  "is_unilateral": true,
  "is_bodyweight": false,
  "instructions_en": [
    "Sit on a leg extension machine and place one foot under the pad.",
    "Rest the other foot on the floor or let it hang.",
    "Extend the working leg until it is nearly straight.",
    "Squeeze the quadriceps at the top.",
    "Lower the leg back down under control.",
    "Complete reps on one side, then switch."
  ],
  "instructions_de": [
    "Setze dich an die Beinstreckermaschine und platziere einen Fuß unter dem Polster.",
    "Lasse den anderen Fuß auf dem Boden ruhen oder frei hängen.",
    "Strecke das arbeitende Bein, bis es nahezu gerade ist.",
    "Spanne den Quadrizeps am oberen Punkt an.",
    "Senke das Bein kontrolliert wieder ab.",
    "Absolviere die Wiederholungen auf einer Seite, dann wechsle die Seite."
  ],
  "instructions_es": [
    "Siéntate en una máquina de extensión de piernas y coloca un pie bajo la almohadilla.",
    "Deja el otro pie apoyado en el suelo o colgando.",
    "Extiende la pierna de trabajo hasta que quede casi recta.",
    "Contrae el cuádriceps en la parte alta.",
    "Baja la pierna con control.",
    "Completa las repeticiones de un lado y luego cambia."
  ],
  "tips_en": [
    "Squeeze the quadriceps hard at the top of the movement.",
    "Lower the weight under control rather than letting it drop.",
    "Keep your back flat against the pad."
  ],
  "tips_de": [
    "Spanne den Quadrizeps am oberen Punkt der Bewegung stark an.",
    "Senke das Gewicht kontrolliert ab, statt es fallen zu lassen.",
    "Halte den Rücken flach am Polster."
  ],
  "tips_es": [
    "Contrae con fuerza el cuádriceps en la parte alta del movimiento.",
    "Baja el peso con control en lugar de dejarlo caer.",
    "Mantén la espalda plana contra el respaldo."
  ],
  "met": 5.0,
  "images": {
    "flat": {
      "start": "images/flat/single-leg-extension-start.webp",
      "peak": "images/flat/single-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 === "single-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.