Flexibility Testing
Flexibility testing measures the available range of movement around a joint or series of joints.
It is widely used in professional fitness assessment, occupational health, rehabilitation, sports science and physical-performance testing.
Flexibility is influenced by factors including joint structure, muscle length, connective tissue, age, activity level and testing technique.
Cartwright Fitness provides professional assessment tools and equipment for measuring flexibility consistently and interpreting results against appropriate reference data.
What Is Flexibility?
Flexibility describes the ability of a joint or group of joints to move through a range of motion.
It can be influenced by:
Muscle length
Joint structure
Connective tissue
Age
Sex
Training history
Injury
Testing position
Because flexibility is joint- and movement-specific, a single test does not represent flexibility across the entire body.
Why Measure Flexibility?
Flexibility testing can help practitioners:
- establish baseline physical capability
- compare results with reference data
- monitor change over time
- support rehabilitation
- contribute to occupational fitness assessment
- assess physical function
- support sports-performance profiling
- form part of a wider assessment battery
The test selected should be appropriate for the movement or physical quality being assessed.
Sit & Reach Test
The Sit & Reach Test is one of the most widely used field assessments of flexibility.
It primarily assesses flexibility of the posterior chain, particularly the hamstrings and lower back.
During the test, the participant sits with the legs extended and reaches forward along a measuring scale.
The distance reached is recorded and may be compared with published reference values.
Sit & Reach Assessment
A raw Sit & Reach result becomes more useful when it can be interpreted against appropriate age- and sex-specific reference data.
Cartwright Fitness provides a free Sit & Reach Assessment that allows practitioners to enter a measured result and compare it with published normative values.
Try the Sit & Reach Assessment Shop Flexibility Testing Equipment
What Does the Sit & Reach Test Measure?
The Sit & Reach Test is often described as a measure of hamstring and lower-back flexibility.
However, the result can also be influenced by:
arm length
leg length
spinal mobility
hip mobility
pelvic position
testing technique
For this reason, Sit & Reach should be treated as a standardised field measure rather than a direct measurement of one specific muscle group.
Standardising the Sit & Reach Test
A professional testing protocol should define:
- participant starting position
- footwear
- knee position
- foot placement
- measuring box or scale
- warm-up
- number of attempts
- whether bouncing is permitted
- how the final result is recorded
Changing these conditions can affect the measurement.
Repeat tests should therefore use the same protocol wherever possible.
Sit & Reach Equipment
A professional Sit & Reach test typically requires a dedicated measuring box or standardised measuring scale.
Using appropriate equipment helps improve consistency between participants and testing sessions.
Cartwright Fitness supplies professional flexibility-testing equipment for structured physical assessment.
Explore Professional Fitness Testing Equipment
Relevant equipment
Sit & Reach testing equipment
Use a dedicated Sit and Reach Box to improve consistency of setup and measurement between participants and repeat tests.
Flexibility vs Mobility
Flexibility and mobility are related but different concepts.
Flexibility generally refers to the passive range available around a joint or muscle group.
Mobility usually refers to the ability to actively control movement through a range of motion.
A participant may therefore have a large passive range of motion but limited control within that range.
Professional assessment should be clear about which quality is actually being measured.
Flexibility Testing in Occupational Fitness
Flexibility may be relevant to some occupations where workers need to:
reach
bend
kneel
climb
work in restricted positions
move equipment
perform repeated physical tasks
However, a generic flexibility score should not automatically be treated as evidence of job-specific capability.
The test should be related to the actual physical demands of the role.
Explore Occupational Fitness Assessment
Flexibility Testing in Sport
Sports-performance programmes may use flexibility testing to monitor movement capability relevant to a particular activity.
Different sports place different demands on flexibility.
Examples include:
Gymnastics
Martial arts
Athletics
Rowing
Cycling
Swimming
Team sports
The assessment selected should match the movement requirements of the sport rather than relying on a single general flexibility test.
Flexibility Testing in Rehabilitation
Flexibility and range-of-motion assessments can also be useful in rehabilitation.
Measurements may help practitioners:
establish a baseline
monitor progress
compare sides
assess return of movement
track response to treatment
In rehabilitation settings, a more joint-specific assessment may be appropriate than a general Sit & Reach Test.
Interpreting Flexibility Results
Flexibility results should be interpreted in context.
A larger range of motion is not always automatically better.
The appropriate level of flexibility depends on:
the participant
the joint being assessed
the physical demands of the activity
injury history
the purpose of the assessment
Very high flexibility may be useful in some activities but unnecessary in others.
Professional interpretation should therefore avoid arbitrary assumptions that more flexibility always means better physical function.
Age and Sex Differences
Flexibility can vary across age and sex.
Published reference data may therefore use age- and sex-specific values when classifying results.
When using normative data, practitioners should check:
- who was included in the reference population
- how the test was performed
- which protocol was used
- whether the equipment matched
- whether the participant is comparable with the reference group
This helps avoid overinterpreting a score against inappropriate norms.
Flexibility Assessment Batteries
Flexibility testing is often more useful when combined with other physical measurements.
A broader professional assessment might include:
Aerobic fitness
Strength
Power
Flexibility
Body composition
This creates a more complete picture of physical capability than any single test alone.
Explore Professional Fitness Assessment
Free Flexibility Assessment Tools
Cartwright Fitness provides a free professional Sit & Reach Assessment.
The wider Professional Assessment Tools library also includes tests for:
Aerobic fitness
Strength
Power
Body composition
View All Professional Assessment Tools
Recording Flexibility Results
Professional organisations may need to record more than a single measurement.
A complete flexibility assessment record may include:
participant details
test protocol
equipment used
best attempt
previous results
reference interpretation
assessment date
Consistent record keeping helps practitioners compare results over time.
Cartwright Assess
Cartwright Assess is being developed to bring multiple physical assessments into one participant record.
Flexibility measurements will sit alongside:
Aerobic fitness
Strength
Power
Body composition
within the same professional assessment workflow.
The intended process is:
Measure → Record → Interpret → Compare → Report
Evidence-Led Flexibility Assessment
A professional flexibility result should explain how the measurement was obtained.
Where appropriate, Cartwright Fitness assessment resources identify:
- testing protocol
- participant position
- equipment
- units
- reference population
- age and sex considerations
- limitations
- supporting evidence
This helps practitioners interpret results consistently rather than relying on arbitrary classifications.
Professional Flexibility Testing
Evidence & reference sources
Flexibility tests should be interpreted as measures of the movement and protocol actually used. Meta-analytic evidence suggests the sit-and-reach has moderate validity for estimating hamstring extensibility but low validity for lumbar extensibility, reinforcing the need to avoid over-generalising a single score.
Cartwright Fitness provides assessment tools and professional equipment for organisations measuring flexibility and physical capability.
The starting point should always be:
What movement or physical quality do you need to assess?
From there, an appropriate test and protocol can be selected.
The objective is not simply to record the furthest distance someone can reach.
It is to create a flexibility measurement that is standardised, repeatable and useful for the purpose of the assessment.