There are two prevailing theories regarding why foam rolling works:

1. Foam rolling creates length change based on the principle of autogenic inhibition, which involves the sensory receptors of the Golgi tendon organ (GTO) and muscle spindle. The GTO senses tension placed on a muscle, while the spindle identifies length change and the rate of change within a particular muscle. Autogenic inhibition is the response that occurs when a muscle is placed under tension and the GTO sends a signal to the spindles to allow the muscle to lengthen. The pressure of the foam roller on the muscle increases tension on the muscle fibers, signaling the GTO to allow the muscle spindles and fibers to lengthen.
2. The second hypothesis suggests that rolling muscle and connective tissue on a foam roller creates friction between the roller and the involved muscle that generates heat, which causes the tissue to become more gel-like and, thus, more pliable.

While your clients may be less interested in how it works, they definitely want to know why they should be foam rolling on a regular basis. Here are six specific benefits of using foam rollers that you can share with your clients or group fitness participants. The more helpful information you can provide, the more others will look to you as a credible and reliable source of fitness information, which only helps to further your success as a health and fitness professional. 

1. Using foam rollers can reduce the risk of developing adhesions. Tissue adhesions are created as the result of collagen binding between layers of muscle. If a muscle is held in a specific position during extended periods of inactivity or overused during repetitive motions, collagen can form between the layers of skeletal muscle, which can create adhesions or knots that restrict the ability of muscle sheaths to slide against one another. The friction and pressure created by the regular use of a foam roller can keep collagen from binding between layers of muscle tissue.
2. Myofascial release can reduce tissue tension and muscle tightness to increase joint range of motion (ROM). When adhesions bind between layers of tissue, they can cause a muscle to remain in a shortened position, which subsequently increases tension on surrounding muscles and restricts joint motion. Regular use of foam rollers for myofascial release can alleviate muscle tightness, helping to ensure optimal joint ROM and enhance overall movement performance.
3. Foam rollers can help restore the proper length-tension relationship to muscles. A number of muscles work together to create joint motion; if one segment of tissue becomes tight, it creates an imbalance that can cause the muscles working on the opposite side of a joint to lengthen and become inhibited. This means they will not produce the proper amount of force for optimal motion. Using a foam roll for myofascial release can reduce tightness to ensure a proper balance of competing forces around a joint. It is best to use foam rolling as a warm-up before using multiplanar patterns that adequately create the full extensibility of the involved tissue.
4. Foam rollers help reduce soreness after an exercise session to promote the recovery process. The natural inflammation that occurs during the tissue-repair process combined with a lack of movement after an exercise session could be a cause of muscle adhesions. Exercise-induced muscle damage signals the repair process. This is when new collagen molecules are formed to help repair injured tissue. If tissue is not moved properly during this repair process, the collagen could bind between layers of muscle creating adhesions. Using a foam roller after exercise can help minimize the risk of the new collagen forming adhesions between layers.
5. The pressure from rolling can help increase blood flow and elevate heat in the involved tissue. Using foam rollers helps reduce tightness and increase joint ROM, which is important prior to a challenging workout. When using a foam roller during a warm-up, be sure to use it only for a brief period of time to elevate tissue temperature and reduce tension. Applying pressure with a foam roller for an extended period of time could desensitize the muscle and affect its ability to contract during the workout.
6. Myofascial release can help promote a feeling of relaxation after a workout, an important psychological benefit. When using a foam roller during the post-workout cool-down, aim to move at a consistent tempo of approximately 1 inch per second; focus on areas of tension for up to 90 seconds to allow the tissue to relax and lengthen.

In general, foam rollers provide the greatest response when placing a body part directly on top of the roller and moving rhythmically to apply pressure to the underlying tissues.

As with any mode of exercise, it’s important to understand both the advantages and disadvantages and identify the best practices for how it can be used with training clients or class participants. It is up to you to identify the best time to apply foam rolling for a client’s specific needs; for a more detailed explanation of how foam rollers create a myofascial release.

Types of Foam Rollers and their Benefits

As foam rolling has grown in popularity, a greater variety of rollers have been created, each promoting specific types of benefits.
Type	Description	Advantages	Disadvantages
Soft-core foam roller	A soft foam roller that is easier to compress and places less force directly on the muscle.	The pliable surface allows greater contact with muscle tissue.  May be more comfortable when first introducing clients to foam rolling.	Over time, repeated use can cause the foam to change shape and become compressed, which reduces its effectiveness.  May not apply enough force for extremely active and fit individuals.
Hard-core foam roller	A foam roller with an outer surface of the foam and an inner core made from hard plastic.	Will maintain shape over repeated uses. Can apply a significant amount of pressure to the contact area of the muscle.	May apply too much pressure and be uncomfortable for certain individuals.
High-density foam roller	These rollers are made from specific types of dense foam that are more resistant to compression.	The density of the foam roller allows greater pressure to be placed on areas of adhesion and tightness. The thicker foam allows the roller to maintain its shape for a longer period of time. A good option for individuals who may not experience benefits from a soft roller, but are not yet ready for a roller with a hard inner surface.	May be too dense and cause discomfort for certain individuals.
Textured foam rollers (the surface has patterns or grooves)	The external surface of the foam roller has a specific pattern or grooves that places pressure on different parts of the tissue.	The theory is that the patterns or texture on the surface of the roller place different amounts of pressure on the muscle, thus promoting circulation.	Depending on the type of roller, the patterning could cause increased pressure in certain areas, leading to localized feelings of discomfort or an excessive amount of pressure in specific areas.
Balls	The circular shape of a ball allows pressure to be focused on specific areas. Like foam rollers, balls come in a variety of sizes and densities. Many companies make specific SMR balls, but almost any type of ball (e.g., golf, tennis, lacrosse, or inflatable) can be used.	The density and size of the ball allow pressure to be placed directly on specific areas of the muscle.	The surface of the ball may be difficult to adjust to a targeted area of adhesion. Certain balls may be too dense and cause discomfort or pain.
Rolling sticks	These are hand-held tools that can be used to apply pressure and create friction directly on specific adhesions or areas of tightness.	Allows force to be applied directly to adhesion or area of discomfort.	It can be hard to use on certain parts of the body, such as the lumbar or thoracic spine.
Vibrating foam roller	This roller features an internal motor that vibrates at a specific frequency of oscillation	Along with the pressure from the roller, vibrations can create a reflexive action in the muscle spindles that causes them to lengthen to reduce tension in the tissue.	The vibrations may be uncomfortable or cause an unintended response such as a headache.

Author: Pete McCall, MS, CSCS, is an ACE Certified Personal Trainer and long-time player in the fitness industry. He has been featured as an expert in the Washington Post, The New York Times, Los Angeles Times, Runner's World, and Self. He holds a master's degree in exercise science and health promotion, and several advanced certifications and specializations with NSCA and NASM.