Definition:It refers to the measurement of angles created at human joints by the bones of the body.

 Why Goniometry? In rehab and sports performance settings, goniometry is most often used to refine exercise or intervention selection. Relevant goniometric assessments highlight hypo-mobility in osteokinematic range of motion, implying which release, flexibility and mobility techniques may be appropriate. In essence, goniometry will assist the practitioner in building a more refined flexibility/mobility routine. Less often, goniometry will highlight hyper-mobility implying the need for activation and stabilization techniques.  

Parts of a Goniometer:

• Body (Fulcrum) – The body of a goniometer is the centerpiece, usually circular or semicircular, with a protractor printed on its face and the fulcrum of the movement arm at its center.
  • Generally, the fulcrum of the goniometer is placed over the center of a joint during measurement.
• Stationary Arm (Stabilization Arm) – The arm that is affixed to the body of the goniometer in such away that it’s relative position does not change.
  • Generally, the stationary arm is aligned with a reference line that does not move during measurement.
• Moving Arm (Movement Arm) – The arm that is affixed to the face of the goniometer at it’s fulcrum; and is free to move the full range of degrees printed on the face of the goniometer.
  • Generally, the movement arm follows the moving bone during measurement.

What are We Measuring?

Goniometry measures osteokinematic range of motion in degrees.

Osteokinematics (Movement of bones) – Movement of bones around a joint; described by the terms flexion, extension, abduction, adduction, etc. You may think of this in terms of movement of the shafts of bones relative to one another.

• Arthrokinematics is the Movement between  joint surfaces – Small amplitude movements in the terms of  roll, glide, spin, compression and distraction. Both Arthrokinematics and osteokinematics must occur simultaneously.
  • Goniometry is a measurement of osteokinematic motion.  Goniometry is not a direct measure of arthrokinematic motion. It is  the amount of measurement of osteokinematic motion available at a joint in total number of degrees.

Unit of Measurement: Goniometry is measured in degrees. The angle between a bone and reference line. That reference line is most often related to “anatomical position” of a bone. A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol).

Hyper-mobility versus hypo-mobility:

• Hyper-mobility – the range of motion is greater than normal values.
• Hypo-mobility – the range of motion is less than normal values

Normal values are established via research on joint motion across various demographics; this research is well-cited and discussed in Measurement of Joint Motion: A Guide to Goniometry, 3rd Edition. .

Note: There is no evidence to suggest that their is a benefit to flexibility beyond normal, or having tightness in tissues that are responsible for force production.

Many dancers and who involved in every day yoga, they complain of orthopedic issues at a much younger age than other people (not doing any exercise).These issues may be the result of hyper-mobility (eg. Prone Mckenzie extension)

Range of Motion and End Feels:

Range of motion:

• Passive (PROM) – The amount of motion achieved by the practitioner without assistance from the patient.
• Active (AROM)– The amount of motion achieved by the patient without any assistance from the practitioner.
• Active Assisted (AAROM) – The amount of motion achieved when the practitioner applies additional force to a range of motion

• Type of End Feels:
  • Soft – An example of a normal soft end feel is the end of elbow flexion, in which the flexor mass of the forearm meets the biceps brachii.
• Firm – This end feel has been described as “the way it feels to pull a leather strap to its end range.”
  • An example of a normal firm end feel is the end of dorsiflexion or shoulder internal rotation.
  • Hard –  Example of a normal hard end feel is the end of elbow extension.
  • Empty – Example of an empty end feel can be seen in the individual who “threw their back out” and will not bend forward due to pain and spasm.

Notes:

• Soft, firm and/or hard end-feels can be normal or abnormal depending on the joint. For example, a soft end feel at the limit of elbow extension may indicate effusion (swelling), where as a firm end feel is short of terminal extension may indicate adaptive shortening of the joint capsule, ligaments and other soft tissues.

Things to know:

• know Functional Anatomy – The more anatomy you understand the more information you will gain from each goniometric assessment. For a much deeper look at anatomy
• Start with a Dynamic movement– The Overhead Squat Assessment, is used to highlight which body segments and ranges should be assessed by using goniometry.
• Exercise – Some experience with therapeutic exercise (and the Overhead Squat Assessment) is also recommended prior to adding goniometry to your assessment/evaluation process.

A Good and a Bad Test:

• Goniometry is valid tool. It is as long as used to measure the range of motion (ROM) of a joint. It is not used to infer the length of a muscles crossing that joint .

Reliability – the overall consistency of a measure.

General guidelines for enhancing the reliability of Goniometry:

• Assessment parameters are carefully followed (example, landmarks
  • Extremity assessments are generally more reliable than assessments of the spine.
  • Large joint assessments are generally more reliable than small joint assessments 
  • Stable positions are generally more reliable than unstable positions.
  • At least 5 degrees difference denotes a change in range of motion (this accounts for a margin of error)
• What is the Relevance of Goniometry:
  • Goniometry is most often used to refine exercise or intervention selection. Most often, reliable and relevant goniometric assessments highlight 
• hypo-mobility in osteokinematic range of motion, implying which release, flexibility and mobility techniques may be appropriate. 

Goniometry guideline:

• Goniometry is most often used to refine exercise or intervention selection. Reliable and relevant assessments highlight hypo-mobility or hyper mobility in osteokinematic range of motion. Through which we can identify which release, flexibility and mobility techniques may be appropriate for the patient. In essence, goniometry will assist the practitioner in building a more refined flexibility/mobilityroutine. It also highlight which corrective exercise is helpful.
• Goniometry may be used as an “objective measure” when you find any compensation or restricted joint of motion during over head squat assessment. Where as gross movement assessment (eg. Over head squat assessment) can only implicate all structures at a joint that has adopted compensatory changes in length, extensibility and activity – goniometry may assess individual joint motions.

Reduces Potential Structures – for instance,an individual exhibits “knees bow in” during an overhead squat assessment, but hip range of motion is normal. This individual may not require any release, mobility and lengthening techniques. But more attention should be given to compensation and a loss of range of motion at the ankle.

• Highlights Additional Structures – for an instance, an individual or patient exhibits excessive forward lean during an overhead squat assessment, and shows restricted knee flexion during goniometric assessment. This may imply that in addition to a loss of extensibility in those structures that restrict dorsiflexion and over-activity of muscles that flex the hip. 
• Confirms Findings of Gross Movement Assessment – If an individual exhibits “arms fall” during an overhead squat assessment, also exhibits a loss of shoulder flexion and external rotation. Although this does not add or reduce the potential limiting structures, it does add an objective measure to the compensation noted.

Goniometric assessment may also be used to add objective, ordinal data to a group of movement assessments. Goniometry may be reliably used  to track the amount of  range of motion gained in each session (ordinal data), or after a set of interventions.

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