KŌMØ LIBRARY

MOBILITY · MUSCLE · 7 MIN

Why do stairs become more difficult?

Stairs concentrate several demands into a few seconds: lifting the body, controlling single-limb support, producing power and preparing the next step.

Three things to know
01Stairs place high mechanical demands on knee and hip extensors.
02Descending also requires precise eccentric control to brake the body.
03Difficulty may reflect reduced reserve rather than absolute incapacity.

Why stairs are demanding

Unlike level walking, stair ascent raises the centre of mass against gravity while balance must be controlled on a relatively small base of support.

The idea of reserve

If maximal capacity decreases, the same stair can consume a larger proportion of the available muscular reserve.

Up and down are different

Ascending requires positive mechanical work; descending requires controlled braking. One direction may therefore feel harder than the other.

Established evidenceFactual statements are grounded in the publications listed below.
KŌMØ perspectiveKŌMØ favours a multidimensional, longitudinal reading of mobility.
LimitsThis page is educational and does not replace medical assessment when a change is recent, marked or accompanied by other symptoms.
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