Range of Motion: Active, Passive, and Active-Assistive Types Explained

What are 3 types of ROM?

There are three primary types of Range of Motion (ROM) crucial for understanding human movement and rehabilitation: Active Range of Motion (AROM), Passive Range of Motion (PROM), and Active-Assistive Range of Motion (AAROM).

Understanding Range of Motion (ROM)

Range of Motion (ROM) refers to the full movement potential of a joint, encompassing the degree to which a joint can be moved in a specific direction. It is a critical component of physical fitness, directly impacting flexibility, mobility, and the ability to perform daily activities, exercises, and sports. Understanding the different types of ROM is fundamental for fitness professionals, therapists, and anyone interested in optimizing their physical capabilities or recovering from injury, as each type serves distinct purposes in assessment, training, and rehabilitation.

1. Active Range of Motion (AROM)

Definition: Active Range of Motion (AROM) is the movement of a joint that is performed solely by the muscles surrounding that joint, without any external assistance. The individual actively contracts their own muscles to move the body part through its available range.

Characteristics & Purpose:

• Self-Initiated: The force driving the movement comes entirely from the individual's muscular contraction.
• Assesses Muscle Strength and Control: AROM directly demonstrates the individual's ability to voluntarily move a limb and the strength of the muscles involved. It also indicates neuromuscular control and coordination.
• Functional Movement: Most daily activities and exercises (e.g., walking, lifting, reaching, squatting) involve AROM.
• Benefits: Improves muscular strength, endurance, coordination, balance, and proprioception. It also helps maintain joint health by promoting synovial fluid circulation.

Examples:

• Performing a bicep curl with a dumbbell.
• Lifting your arm overhead without assistance.
• Walking or running.
• Doing a bodyweight squat.

2. Passive Range of Motion (PROM)

Definition: Passive Range of Motion (PROM) is the movement of a joint that is performed by an external force, such as a therapist, a machine, a partner, or even gravity, without any muscular contraction from the individual. The individual's muscles remain relaxed throughout the movement.

Characteristics & Purpose:

• External Force: The movement is produced by an outside agent, not the individual's muscles.
• Assesses Joint Integrity and Flexibility: PROM helps to determine the anatomical limits of a joint and the extensibility of the surrounding soft tissues (ligaments, joint capsule, non-contractile elements of muscles). It can identify joint restrictions or pain points.
• Prevents Stiffness and Maintains Mobility: Crucial in situations where an individual cannot actively move a limb (e.g., paralysis, post-surgery, severe weakness) to prevent contractures, maintain joint lubrication, and promote circulation.
• No Muscle Strengthening: PROM does not directly strengthen muscles, as they are not actively contracting.

Examples:

• A physical therapist moving a patient's leg through its range of motion while the patient relaxes.
• Using a Continuous Passive Motion (CPM) machine after knee surgery.
• A partner stretching your hamstring.
• Gravity pulling your arm down after it has been lifted.

3. Active-Assistive Range of Motion (AAROM)

Definition: Active-Assistive Range of Motion (AAROM) is a hybrid type where the individual initiates the movement with their own muscular contraction, but an external force provides assistance to complete the movement through the full available range. This assistance is typically needed when the individual's muscles are too weak to achieve full AROM.

Characteristics & Purpose:

• Combination of Forces: Involves both internal (muscular contraction) and external (therapist, machine, other limb) forces.
• Bridge Between PROM and AROM: AAROM is commonly used in rehabilitation to progressively increase muscle strength and control, allowing individuals to gradually transition from passive movement towards independent active movement.
• Gradual Strengthening and Control: It helps to re-educate muscles, improve neuromuscular coordination, and increase muscular endurance in a controlled manner.
• Prevents Overexertion: Provides support to prevent injury or excessive strain on weakened muscles.

Examples:

• Using a pulley system to help lift an arm overhead when shoulder muscles are weak.
• A physical therapist providing light support to a patient's leg as they try to bend their knee.
• Using your stronger arm to assist the weaker arm in performing a movement (e.g., lifting a light weight).
• Performing leg slides with a towel under the heel to reduce friction and assist movement.

Why Differentiate ROM Types?

Understanding the distinctions between AROM, PROM, and AAROM is vital for several reasons:

• Accurate Assessment: Therapists and trainers use these distinctions to accurately assess joint health, muscle strength, flexibility, and identify limitations or pain points.
• Targeted Intervention: The specific type of ROM employed dictates the treatment or training approach. For instance, PROM is used when active movement is contraindicated or impossible, AAROM for progressive strengthening, and AROM for functional training.
• Rehabilitation Progression: Rehabilitation protocols often move clients from PROM to AAROM, and finally to AROM as strength and control improve.
• Injury Prevention and Performance Enhancement: Knowing which type of ROM is appropriate for a given situation helps optimize training, prevent injuries, and enhance athletic performance.

Practical Applications and Considerations

For anyone involved in fitness, rehabilitation, or personal health, applying the knowledge of ROM types is key:

• For Personal Trainers: Differentiate between a client's active flexibility (AROM) and passive flexibility (PROM) to design effective stretching and strengthening programs.
• For Physical Therapists: Prescribe the correct type of ROM exercises based on a patient's injury, surgical status, and rehabilitation phase.
• For Individuals: Understand how to safely improve their own mobility, whether through active stretching (AROM), assisted stretching (AAROM), or recognizing when passive movement is necessary (e.g., during recovery from an injury).
• Pain as a Guide: During any ROM exercise, pain is a critical indicator. Movement should generally be performed within a pain-free range, especially during rehabilitation.

Conclusion

The three types of Range of Motion—Active, Passive, and Active-Assistive—provide a comprehensive framework for understanding how joints move and how to assess, train, and rehabilitate the musculoskeletal system. Each type offers unique insights into an individual's physical capabilities and plays a distinct role in maintaining joint health, restoring function, and optimizing human movement. By appreciating these nuances, fitness enthusiasts, personal trainers, and healthcare professionals can make more informed decisions to promote health, prevent injury, and enhance performance.