Range of motion (ROM) is a fundamental measure in physical therapy, representing the distance and direction a joint can move between its flexed and extended positions. Physical therapy is the health profession focused on evaluating and treating movement disorders through physical means, aiming to improve a patient’s quality of life. When injury, surgery, or illness restricts this movement, therapeutic exercises are necessary to restore mobility and function. A common technique employed in rehabilitation to regain lost movement is Active Assisted Range of Motion, often referred to by the acronym AAROM.
What Active Assisted Range of Motion Means
Active Assisted Range of Motion is a hybrid exercise that requires the patient to exert voluntary muscle effort while also receiving external support to complete the desired movement. The patient actively contracts the muscles controlling the joint to initiate the motion and move the limb as far as their current ability allows. This initial active effort distinguishes it from movements where the patient is completely passive.
Once the patient reaches the limit of their independent movement, an external force gently guides the limb through the remaining available range. This assistance is carefully controlled, ensuring the patient’s muscle is still engaged but not overworked or damaged. The dual nature of AAROM allows the patient to maintain neurological pathways for movement while safely progressing the joint’s flexibility beyond weakness or pain. The amount of active contraction versus external assistance is continuously adjusted by the therapist based on the patient’s specific needs and tolerance.
The Full Spectrum of Movement in Physical Therapy
To understand AAROM, it helps to place it within the full spectrum of movement used in rehabilitation, which includes three primary categories. At one end is Passive Range of Motion (PROM), where the patient supplies no muscular effort, and the entire movement is performed by an external force, such as a therapist or a mechanical device. PROM is typically used when a patient is paralyzed, comatose, or when active muscle contraction is medically contraindicated, such as immediately following a severe injury or surgery.
At the opposite end of the spectrum is Active Range of Motion (AROM), which requires the patient to move the joint independently through the entire range solely by contracting their own muscles. This type of exercise is used when the patient has sufficient muscle strength to fully control the limb without external support. AROM serves to improve strength and coordination, and it is usually introduced later in rehabilitation when tissues are adequately healed.
AAROM occupies the transitional space between these two extremes, acting as a bridge to full independence. It combines the external support of PROM with the internal muscle engagement of AROM. The patient is required to actively participate, but the external assistance compensates for insufficient strength, pain, or weakness that prevents reaching the full range of motion. This makes it a crucial tool for patients progressing toward full recovery and AROM.
When and How Assistance is Provided
AAROM is a treatment choice when the patient’s muscle power is diminished but not entirely absent, a condition quantified using the Manual Muscle Testing (MMT) scale. AAROM is utilized when muscle strength is graded as a 2 or 3 out of 5. A muscle graded 2 moves the joint through its full range only if gravity is eliminated, while a grade 3 muscle moves the joint through the full range against gravity but cannot tolerate external resistance. In both scenarios, assistance is necessary to ensure the joint moves through the complete therapeutic arc.
Assistance can be delivered in several practical ways, depending on the joint and the rehabilitation setting. The most common method is manual assistance, where a physical therapist uses their hands to support the limb and guide the movement. This allows for fine-tuned control over the speed and force of the assistance, which is useful when protecting newly repaired tissue, such as after rotator cuff surgery.
Patients can also perform self-assisted movements, often by using their unaffected limb to help the injured side move through the range of motion. Furthermore, mechanical assistance is employed using devices like shoulder pulleys, sliding boards, or gravity itself, which can be manipulated by changing the patient’s body position. These techniques ensure that the movement is achieved safely, balancing the need for muscle engagement with the need to protect healing structures.
Therapeutic Objectives of Using AAROM
The primary clinical goal of choosing AAROM is to encourage the first stages of muscle re-education and strength development. By requiring the patient to activate the muscle, the exercise provides a controlled, low-load stimulus that helps rebuild neuromuscular connections. This active component minimizes the rapid muscle wasting, known as atrophy, that occurs with prolonged disuse or immobilization.
AAROM also serves to maintain the flexibility of soft tissues, preventing the shortening of muscles, ligaments, and joint capsules that can lead to contractures and persistent joint stiffness. Moving the joint structures through the available range promotes the health of the articular cartilage. The gentle muscle pumping action also helps promote local circulation, which is beneficial for tissue healing and reducing swelling.
The active participation maintains the patient’s sensory awareness of the limb’s position and movement, known as proprioception. By bridging the gap between passive movement and full unassisted movement, AAROM allows for progressive loading of the healing tissue. This gradual transition is carefully managed to prepare the muscle for the higher demands of full Active Range of Motion without risking re-injury.