There is no single number that completely describes how well a person functions physically.

Someone can be strong but have poor balance.

They can walk quickly over a short distance but fatigue rapidly.

They can have good joint mobility but struggle to generate power.

They can improve in one area of physical function while remaining unchanged in another.

Physical function is not one capability

The term physical function can include several different but related abilities.

These may include:

• Strength
• Mobility
• Balance
• Endurance
• Power
• Range of motion
• Walking ability
• Everyday functional capacity

Different assessments reveal different parts of that picture.

A grip-strength measurement tells us something different from a walking test.

A Timed Up and Go captures something different from a Sit-to-Stand assessment.

A balance test measures something different again.

None is inherently better. They answer different questions.

The same overall limitation can have different causes

Consider two older adults who both struggle to get around independently.

One may primarily have reduced leg strength.

The other may have adequate strength but poor balance and confidence.

Their functional limitation might appear similar. The underlying problem is not.

That distinction can influence intervention, monitoring and expectations for recovery.

The same applies during rehabilitation.

A patient’s Sit-to-Stand performance may improve while walking endurance remains limited.

Another patient’s walking speed may improve even though balance has changed very little.

If only one dimension is being followed, part of the patient’s trajectory may remain invisible.

Multiple measurements create a richer picture

The purpose of multidimensional measurement is not to create an enormous battery of tests for every patient.

It is to measure the dimensions that matter for the clinical question.

For one patient, that might mean lower-body strength and mobility.

For another, balance and walking capacity.

For another, strength, range of motion and pain.

The key is to bring those measurements together.

From individual tests to a functional profile

One way to think about physical-function measurement is as a profile rather than a score.

A profile could show how several relevant dimensions develop over time.

• Lower-body strength may improve steadily.
• Mobility may initially improve and then plateau.
• Walking endurance may remain below target.
• Balance may deteriorate slightly.

Looking at these together gives a different understanding of the patient’s situation than any individual result.

Instead of saying:

The data may allow a more specific description:

That is a more informative picture.

Kinegrade is being designed around this broader view

Kinegrade’s long-term vision is to make several dimensions of physical function easier to measure and follow.

This can include standardized assessments of strength, mobility, balance, functional capacity and related measures.

Some assessments may use existing clinical devices.

Others may increasingly use the smartphone itself.

Computer vision could support movement-based tests. Phone sensors could assist with certain mobility or range-of-motion measurements. Patient-reported information could provide additional context.

The important part is not any single technology.

It is bringing relevant measurements together into a coherent longitudinal view.

Better data should make physical function easier to understand

The human body does not improve or deteriorate according to a single metric.

Physical function is the result of several interacting capabilities.

Measurement systems should reflect that reality without making clinical practice unnecessarily complicated.

Because physical function is not one number.

It is a changing profile of human capability.