Passive Vs. Active Range Of Motion (PROM Vs. AROM): A Comprehensive Guide

Learn the distinctions between passive and active range of motion to increase joint mobility and flexibility, their advantages, recommended applications, and testing procedures.

Thank you for reading this post, don't forget to subscribe!

Whether recovering from surgery or managing a chronic condition, knowing about PROM and AROM is helpful. These techniques guide safe movement and joint care. They also help you make better choices for your exercise or recovery plan.

Table of Contents

Understanding Range of Motion (ROM): The Basics

Range of Motion (ROM) refers to how far and how smoothly a joint can move through its natural arc in different directions. Every movement your body makes—from bending a knee to turning your neck—depends on the flexibility and strength of your joints.

Maintaining a healthy range of motion is crucial for staying mobile, preventing stiffness, and performing daily tasks with ease.

Each joint has a specific normal range, measured in degrees, which varies depending on its structure and function. For instance, the shoulder joint allows a wide circular movement, while the knee primarily bends and straightens in one plane.

When joints lose flexibility due to injury, prolonged inactivity, aging, or muscle tightness, mobility can decline significantly.

ROM exercises are designed to keep joints supple and muscles balanced, enhancing both function and comfort. These exercises are divided into two major types—Passive Range of Motion (PROM) and Active Range of Motion (AROM).

While PROM focuses on movement without muscle engagement, AROM emphasizes voluntary muscle use. Together, they create a complete system of joint maintenance and rehabilitation that supports recovery, independence, and long-term physical health.

What is Passive Range of Motion (PROM)? Definition, Purpose, and Application

Passive Range of Motion (PROM) describes the movement of a joint that occurs without the person actively using their muscles. Instead, an external force—such as a physical therapist, caregiver, or mechanical device—moves the joint through its available range.

Think of PROM as the “gentle introduction” to movement when your body isn’t yet ready to do the work on its own. It’s particularly beneficial for people recovering from surgery, those with neurological disorders, or anyone unable to move certain joints independently.

The main purpose of PROM is to preserve joint mobility and prevent stiffness during periods of limited movement. By moving the joint passively, muscles and connective tissues are stretched, circulation improves, and joint capsules remain lubricated.

These controlled movements also help reduce swelling, relieve discomfort, and prevent conditions like muscle contractures (where tissues shorten and restrict mobility).

PROM is most often used:

During post-operative recovery (e.g., knee or shoulder surgery)
After neurological events such as a stroke or spinal cord injury
For patients with chronic immobility (e.g., those confined to bed or wheelchairs)

Even simple, repetitive PROM exercises can make a profound difference in recovery—helping patients maintain flexibility, minimize pain, and prepare for the next stage of rehabilitation.

How Passive Range of Motion (PROM) is Performed

Muscles, tendons, and ligaments may shorten and tighten when joints are immobile for extended periods of time. PROM prevents contracture formation, which is a permanent loss of movement, by maintaining the flexibility of these tissues.

Proper PROM technique includes:

Supporting the limb to avoid unnecessary strain.
Moving slowly and rhythmically to ensure smooth motion and comfort.
Avoid any jerky or forced movement, which can cause injury or inflammation.

PROM can be done manually or mechanically:

Therapist-Assisted PROM: The therapist moves the joint gently, paying close attention to resistance or discomfort.
Continuous Passive Motion (CPM) Machines: These devices automatically move joints (like the knee or elbow) in a controlled cycle, maintaining flexibility during rest.
Gravity-Assisted PROM: Sometimes, gravity itself aids motion—such as allowing a limb to hang off the side of a bed to promote gentle stretching.

Examples of external forces in PROM include:

Examples of external forces in Passive Range of Motion (PROM) include:

Therapist-Assisted PROM: The physical therapist manually moves the patient’s joint through its full motion.
Continuous Passive Motion (CPM) Machines: Automated devices that gently move joints (e.g., the knee or shoulder) to maintain flexibility and prevent stiffness.
Gravity-Assisted PROM: Using gravity to create movement — for instance, letting an arm or leg hang freely off the edge of a bed or table.

Key Benefits of Passive Range of Motion (PROM)

PROM is more than a recovery tool—it’s a vital part of maintaining musculoskeletal health when active motion isn’t possible. Below are its major benefits:

1. Preventing Joint Stiffness and Contractures

Muscles, tendons, and ligaments can shorten and tighten when joints are immobile for extended periods of time. PROM prevents contracture formation, a permanent loss of movement, by maintaining the flexibility of these tissues.

2. Preserving Flexibility and Soft Tissue Integrity

PROM helps retain the elasticity of muscles and connective tissue, ensuring joints maintain their full functional range. This prepares the body for future active movement once healing allows.

3. Enhancing Circulation and Nutrient Delivery

Even gentle movement promotes blood flow, improving oxygen and nutrient delivery to tissues.

Enhanced circulation accelerates healing and prevents complications such as deep vein thrombosis (DVT), which is common after surgery or immobility.

4. Reducing Pain, Swelling, and Inflammation

PROM encourages the release of synovial fluid, a natural lubricant that nourishes cartilage and minimizes friction. This reduces joint pain and stiffness, while promoting smoother, more comfortable motion.

5. Psychological and Emotional Benefits

PROM isn’t just physical—it can also improve mood and confidence. Feeling your body move, even passively, restores a sense of progress and connection, which can be vital during recovery.

Common Conditions Treated with PROM Exercises

PROM exercises are widely used across rehabilitation settings and patient types. Here are the most common scenarios:

Stroke or Neurological Disorders: Helps maintain flexibility and prevent contractures in paralyzed limbs.
Post-Surgical Recovery: Supports early mobility after procedures like ACL reconstruction, joint replacements, or rotator cuff repairs.
Spinal Cord Injuries: Prevents muscle shortening and joint stiffness in paralyzed or partially immobilized limbs.
Severe Arthritis or Chronic Pain Conditions: Reduces discomfort and maintains mobility in joints affected by inflammation.
Prolonged Bed Rest: Prevents bedsores, promotes circulation, and maintains joint mobility in immobile patients.

By incorporating PROM into care routines, caregivers and therapists can significantly improve comfort, prevent complications, and enhance long-term outcomes.

The Role of PROM in Early Rehabilitation

PROM is often the first milestone in recovery—especially when active movement isn’t yet possible. In the initial phase following surgery, stroke, or severe injury, patients may lack the muscle strength, coordination, or confidence to move independently. PROM bridges that gap.

By allowing controlled movement early on, PROM:

Keeps joints nourished and lubricated
Preserves the body’s natural alignment and posture
Prepares muscles and tissues for Active Range of Motion (AROM) exercises later

PROM also plays a preventive role—reducing the risk of stiffness, pressure sores, and secondary injuries caused by immobility. Over time, as healing advances, PROM transitions into active, goal-oriented exercises that rebuild strength and coordination.

This early intervention lays the foundation for a faster, safer, and more complete recovery, allowing patients to regain control, confidence, and functional independence.

Key Differences: Passive vs. Active Range of Motion

Although maintaining or increasing joint mobility is the general objective of both PROM and AROM, their approaches, purposes, and degrees of muscle engagement are very different.

1. Definition and Control

PROM (Passive Range of Motion) is performed by an external source such as a therapist, caregiver, or device. The patient remains relaxed throughout the movement.
AROM (Active Range of Motion) requires the patient to actively use their own muscles to move a joint through its full range without external help.

2. Muscle Engagement

PROM involves no active muscle contraction; it’s purely a mechanical movement designed to prevent stiffness and preserve flexibility.
AROM, on the other hand, activates and strengthens muscles, helping to rebuild endurance, coordination, and control.

3. Purpose in Rehabilitation

PROM is typically used early in recovery, when independent movement isn’t yet possible.
AROM comes later—once the patient has regained sufficient strength and stability to move safely and effectively.

4. Performed By

PROM: Therapist, caregiver, or automated machine
AROM: The patient themselves, guided by a therapist’s supervision or exercise plan

5. Typical Use Cases

PROM: Post-surgery recovery, paralysis, or severe immobility
AROM: Active rehabilitation, muscle strengthening, and functional training

Aspect	Passive Range of Motion (PROM)	Active Range of Motion (AROM)
Definition	Movement of a joint by an external force	Movement of a joint by the individual’s muscles
Muscle Involvement	No muscle activity	Active muscle contraction
Purpose	Maintain joint mobility and prevent stiffness	Strengthen muscles and improve coordination
Used For	Patients unable to move independently	Individuals capable of self-movement
Performed By	Therapist, caregiver, or machine	Patient independently
Common Settings	Post-surgery, paralysis, immobility	Patients are unable to move independently

Comparing Applications in Rehabilitation & Therapy

1. Post-Surgical Recovery: The PROM to AROM Transition

In post-surgical rehabilitation—such as after knee, shoulder, or hip replacement—PROM is the first phase of healing. It allows gentle, guided motion to prevent stiffness and promote circulation while the surgical site heals.

A Continuous Passive Motion (CPM) machine may be used to move the joint repeatedly at a slow, controlled pace, ensuring early flexibility.

As healing progresses and pain subsides, patients gradually transition to AROM exercises. This stage reintroduces active muscle use, helping strengthen supporting muscles like the quadriceps, hamstrings, or deltoids.

The smooth shift from PROM to AROM ensures steady progress without risking reinjury.

2. Safe PROM Techniques for Neurological and Orthopedic Conditions

For patients recovering from neurological disorders (e.g., stroke, multiple sclerosis, spinal cord injury), PROM helps maintain limb mobility and joint health even when voluntary control is lost.

Therapists ensure that:

Movements are slow, smooth, and pain-free.
The entire joint is supported throughout
Communication remains constant to detect discomfort.

PROM should never cause pain—its purpose is preservation, not stretching beyond limits. Forcing a joint can damage tissues or delay recovery.

3. Frequency and Recommended Routine for PROM Exercises

The frequency of PROM depends on the individual’s condition, age, and rehabilitation goals.

Post-surgery or neurological recovery: 2–4 times daily
Bedridden patients: Every few hours to maintain circulation and prevent stiffness
Mild mobility restrictions: Once daily or as needed to maintain range

Each session typically involves 5–10 gentle repetitions per joint, with gradual progression as tolerated. A healthcare professional should guide frequency and intensity to ensure safety and effectiveness.

Active Range of Motion (AROM): Purpose and Step-by-Step Process

Once a patient regains partial strength and healing is stable, Active Range of Motion (AROM) exercises become essential.

Unlike PROM, AROM requires the individual to use their muscles to move the joint through its full range—making it an active part of recovery.

AROM is crucial for:

Strengthening weakened muscles
Enhancing joint coordination and balance
Preventing muscle atrophy (wasting)
Improving independence and functional ability

Step-by-Step Guide to Performing AROM Safely

1. Start with Gentle Movements

Begin with small, slow movements. Avoid sudden or forceful motions that may cause strain or discomfort.
Example: Slowly bending and straightening the elbow or knee to increase tolerance.

2. Focus on Muscle Engagement

Encourage conscious activation of the muscles surrounding the joint.
For instance, during shoulder flexion, the patient should focus on engaging the deltoid and rotator cuff muscles.

3. Perform Controlled Repetitions

A standard program involves 2–3 sets of 10–15 repetitions per exercise, allowing for rest between sets.
As strength improves, gradually increase the range and number of repetitions.

4. Maintain Pain-Free Movement

Pain is a signal to stop or modify the motion. AROM should challenge muscles, not aggravate joints or tissues.

5. Incorporate Goal-Oriented Tasks

Integrate AROM exercises into functional movements, such as reaching for objects, standing from a chair, or climbing stairs. This reinforces practical strength and coordination.

Example AROM Exercises

Shoulder Circles: Strengthens deltoids and increases flexibility.
Wrist Flexion and Extension: Enhances mobility for fine motor control.
Ankle Pumps: Promotes blood flow and prevents swelling in the legs.
Leg Raises and Knee Extensions: Build lower limb strength after injury.

Each of these exercises supports joint function, encourages circulation, and accelerates recovery.

Importance of Range of Motion (ROM) for Long-Term Mobility

Healthy ROM isn’t just for rehabilitation—it’s a lifelong foundation for movement efficiency and comfort.
Without regular joint motion, even everyday activities like walking, dressing, or lifting objects can become difficult.

1. Preventing Joint Stiffness and Degeneration

Joints that aren’t moved regularly tend to stiffen and lose lubrication, leading to discomfort and arthritis-like symptoms. Regular PROM and AROM exercises maintain joint nutrition and structural health.

2. Maintaining Functional Independence

Mobility equals independence. When joints move freely and muscles remain strong, individuals can perform daily tasks—walking, bending, reaching—without assistance.

3. Strengthening Muscles and Preventing Atrophy

AROM directly targets muscle groups, improving tone and endurance. This prevents the weakening and shrinking of muscles that can result from prolonged inactivity.

4. Reducing Chronic Pain and Improving Posture

Consistent ROM exercises reduce compensatory movements that cause imbalance and strain. They help improve posture, joint alignment, and pain tolerance over time.

5. Supporting Healthy Aging

As we age, joints naturally lose some flexibility. ROM exercises slow this process, helping older adults maintain mobility, stability, and confidence in their movements.

FAQs on Passive and Active Range of Motion

Q. What are the main benefits of combining PROM and AROM exercises?

Combining PROM and AROM offers a balanced approach to rehabilitation. PROM maintains flexibility and prevents stiffness when a joint cannot move actively. AROM, on the other hand, builds strength and coordination once healing begins.

Together, they support faster recovery, better muscle control, and improved joint stability. This combination ensures smoother transitions from passive assistance to independent movement, restoring full mobility and function efficiently.

Q. How often should ROM exercises be performed?

The frequency of ROM exercises depends on individual needs and medical conditions. For patients recovering from surgery or who are confined to bed, passive range of motion (PROM) exercises can be performed several times a day to prevent stiffness.

AROM, which requires active effort, is usually performed once or twice daily. The goal is to maintain joint health without overexertion. It’s best to follow a physiotherapist’s recommendation for safe and effective results.

Q. Can ROM exercises prevent long-term disability?

Yes, consistent ROM exercises play a vital role in preventing long-term disability. They keep joints flexible and muscles active, even during limited mobility periods. Regular motion prevents contractures, reduces stiffness, and promotes better posture and coordination.

By maintaining joint function, these exercises help avoid chronic pain and mobility loss. Long-term commitment to ROM routines supports independence and overall physical well-being.

Q. Are ROM exercises safe for older adults?

Yes, ROM exercises are safe and highly beneficial for older adults. They help maintain flexibility, reduce stiffness, and improve circulation in aging joints. Both PROM and AROM can be adjusted to suit comfort and ability levels.

With guidance from a therapist or caregiver, seniors can safely perform these exercises to enhance balance and prevent falls. Regular ROM activity supports joint health and preserves mobility with age.

Q. What equipment can assist in ROM exercises?

Several tools can make ROM exercises easier and more effective. Continuous Passive Motion (CPM) machines gently move joints for PROM sessions. Resistance bands and foam rollers help strengthen muscles during AROM exercises.

Support straps or pulleys can also assist with safe and controlled movements. These tools are commonly used in therapy centers and home rehabilitation programs to improve comfort and consistency during practice.

Q. How do therapists measure Range of Motion?

Therapists measure Range of Motion using a device called a goniometer. This tool calculates the degree of movement a joint can achieve. By placing it on the joint and observing its motion, therapists can identify stiffness or movement limitations.

Regular measurements help track recovery progress and the effectiveness of therapy. This precise assessment ensures that exercise plans are tailored to the patient’s needs and recovery goals.

The Bottom Line: Combining PROM and AROM for Recovery

Understanding the importance and applications of passive and active range of motion (ROM) exercises is key for anyone recovering from injury, surgery, or chronic mobility issues.

Whether you aim to prevent joint stiffness through passive movement or strengthen your muscles through active exercise, these ROM exercises are fundamental in maintaining flexibility, improving function, and ensuring a return to everyday activities.

By applying the right combination of PROM and AROM exercises, individuals can effectively recover from injuries, enhance physical performance, and ensure long-term joint health.