Every joint in a dog’s body is designed for movement and has a “normal” amount of scope it moves through.
This is termed as “Range of Motion”, or ROM, of a joint. There are documented values, measured in “degrees”, which are the standards optimal for each of the joints.
Dogs function best when their ROM is within these normal values.
However, with illness, surgery, or injury, the dog may be less active. Over time their joints become stiff, losing a normal range of motion. Other times, due to trauma, the joint might be dislocated and too loose, unstable.
Measuring range of motion
During a Veterinary or PT evaluation, the joints are examined and the range of motion is measured with a goniometer.
Those joints determined to be tight will be identified and may benefit from specific ROM exercises.
Joints move in various ways. For example, the shoulder and hip are “multi-axial” or the elbow and knee (stifle), which are “hinge” joints.
Movement directionality
Multi-axial range of motion
Multi-axial means that the shoulder (and hip) moves in 3 different planes of movement as well as in 6 directions:
- Extension: in which the arm moves forward and up toward the head;
- Flexion: in which the arm moves in a backward direction toward the tail;
- Abduction: the arm moves away from the body, out to the side;
- Adduction: the arm moves close to and across the body;
- Rotation: the shoulder turns inward and outward to achieve Internal and External rotation;
Hinge joints
The Stifle and Elbow, being “hinge” joints, move in only 1 plane, with 2 directions:
- Flexion: or “bending”;
- Extension: or “straightening;
Wrist joints
The Carpus (wrist) joint moves into 4 directions:
- Flexion: or bending down with the paw tucked in toward the body;
- Extension: or bending up and back as if the paw is in a “wave” position;
- Deviation: where the paw moves from side to side
The hip moves similarly to the shoulder except for the terminology changes slightly. Flexion is where the thigh moves forward and toward the stomach and ribs (“knee to chest”); Extension: where the thigh moves in a backward direction toward the rump;
Ankle joints
The hock (ankle) joint bends in several directions, but the 2 main are:
- Cranial Flexion: “toes up” direction, where the paw bends toward the head;
- Plantar Flexion: “toes pointed” direction, where the paw points away from the body, toward the tail.
When a Veterinarian or Physical Therapist use a goniometer to measure your dog’s ROM, they will document the result, can advise you of the number and explain how it relates to normal values.
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| Goniometric measurement on Guinness |
For example, for a dog that just had sutures removed after CCL surgery, I will measure the degrees of stifle flexion.
A typical result might be 15 degrees. Normal values for stifle flexion are 42 degrees, which makes the current measurement is about 35 % of normal. I will explain to the client
- recovery expectations
- likelihood the dog is to regain full range
- what time frame, etc.
Abnormal range of motion
Abnormal range of motion means that a joint is either
- too tight (hypo mobile)
- or too loose (hypermobile)
Hypermobile joints need rest and restriction from excessive motion. This is achieved with splints or wraps.
With hypomobility, joints need exercise in order to gain flexibility and movement. Range of motion exercises mean moving the joint and surrounding muscles through their available ranges. This movement may be passive, active or active-assisted.
Passive range of motion exercise
Passive range of motion exercises involve an external force without any participation by the dog.
PROM comes in play when the dog is unable to move joints on their own or if self-movement is painful or detrimental.
The technique
Proper technique is essential.
The therapist must cradle and support the limb to avoid jarring or twisting stress on joints. The exercise should be smooth, slow and steady, with the dog relaxed and comfortable. A willing owner can receive detailed supervised instruction to perform basic PROM at home.
An owner ought to receive written instructions or an instructive video. Passive ROM exercises usually involve 5-10 repetitions, 2-3 times per day.
A dog owner who is uncomfortable doing this type of joint motion should be open and honest about it. I never force a client to perform PROM on their dog.
It is better to have a professional provide the service than to have it done incorrectly and risk injury. There is no shame in admitting to feeling “queasy” about this. However, owners should never neglect these exercises.
Active and active-assisted range of motion
The other 2 types of ROM are
- active-assisted
- active
Active-assisted ROM occurs when the therapist guides the dog’s joint motion and the dog’s muscles assist to a partial degree.
Active ROM involves full muscle contraction by the dog. Placing a treat or toy in a certain position can stimulate the dog to move their limb on their own, through ranges of motion.
Other techniques include
- walking in sand or water
- over rails or through a tunnel
Both active and active-assisted methods challenge the joint to the limit of its range. Additional pressure at the end of this range qualifies as “stretching”.
Related articles:
Canine Post-Op Physical Therapy: Best Practices After Your Dog’s Surgery
Further reading:
Passive Range of Motion