10.2 Stairs

Question 1

What percentage of stair-related falls occur during descent?

Answer 1

About 80% of stair falls happen while going downstairs.

Question 2

What are the three key requirements for stair walking?

Answer 2

Progression, stability, and adaptation.

Question 3

What does “progression” refer to in stair walking?

Answer 3

Generating concentric forces to go up or controlling eccentric forces to go down stairs.

Question 4

What does “stability” mean in stair analysis?

Answer 4

Controlling the center of mass over a constantly changing base of support.

Question 5

What does “adaptation” involve in stair walking?

Answer 5

Adjusting movement strategies for stair height, width, or the presence of railings.

Question 6

During stair ascent, what are the three phases of the stance period?

Answer 6

Weight acceptance, pull-up, and forward continuance.

Question 7

During stair ascent, what are the two phases of swing?

Answer 7

Foot clearance and foot placement.

Question 8

Which muscles are most active during the pull-up phase of stair ascent?

Answer 8

Vastus lateralis and soleus (concentric contraction).

Question 9

How does stair ascent differ from level walking in force production?

Answer 9

It requires about twice the force of level walking.

Question 10

Which muscle group generates most of the energy for stair ascent?

Answer 10

The knee extensors.

Question 11

When is the greatest instability during stair ascent?

Answer 11

At contralateral toe-off, when one leg supports total body weight.

Question 12

Which muscles are responsible for foot clearance during stair ascent?

Answer 12

Tibialis anterior (dorsiflexion) and hamstrings (knee flexion).

Question 13

Which muscles control final foot placement in stair ascent?

Answer 13

Hip extensors and ankle dorsiflexors.

Question 14

What are the three stance phases during stair descent?

Answer 14

Weight acceptance, forward continuance, and controlled lowering.

Question 15

What are the two swing phases during stair descent?

Answer 15

Leg pull-through and preparation for foot placement.

Question 16

Which muscles eccentrically absorb energy during stair descent weight acceptance?

Answer 16

Gastrocnemius, rectus femoris, and vastus lateralis.

Question 17

How much ground reaction force occurs at initial stair contact during descent?

Answer 17

Approximately two times body weight.

Question 18

What is the function of the gastrocnemius before foot contact during descent?

Answer 18

It activates early to cushion landing and absorb shock.

Question 19

Which muscles control the “controlled lowering” phase of stair descent?

Answer 19

Quadriceps and soleus (eccentric control).

Question 20

Which muscles initiate leg swing during stair descent?

Answer 20

The hip flexors.

Question 21

At what part of the foot does contact occur during stair descent?

Answer 21

On the lateral border of the foot.

Question 22

How does stair climbing cadence compare to level walking?

Answer 22

Stair climbing has a lower cadence and slower forward speed.

Question 23

How does stride length during stair climbing compare to level walking?

Answer 23

It has a shorter stride length and longer cycle duration.

Question 24

What happens to hip and knee motion at the beginning of stair ascent?

Answer 24

There is more flexion of the lower limb compared to level walking.

Question 25

What happens to hip extension at toe-off during stair ascent?

Answer 25

Less hip extension is observed due to shorter step length.

Question 26

How does reduced knee flexion affect stair performance?

Answer 26

It decreases stair climbing ability; individuals may take one step at a time.

Question 27

How do people with limited dorsiflexion compensate during stair ascent?

Answer 27

They increase hip and knee flexion to clear the step.

Question 28

In what plane are most stair-climbing moments and powers generated?

Answer 28

In the sagittal plane.

Question 29

Why is stair ascent mechanically demanding?

Answer 29

It requires large joint moments to support body weight and propel upward against gravity.

Question 30

Which muscles are critical for stair ascent?

Answer 30

Knee extensors and ankle plantarflexors.

Question 31

Which muscles are critical for stair descent?

Answer 31

Quadriceps and soleus for eccentric control.

Question 32

What clinical abilities can stair analysis help assess?

Answer 32

ROM, strength, coordination, and balance.