Assessment & Research

Leg muscle activation patterns during walking and leg lean mass are different in children with and without developmental coordination disorder.

Yam et al. (2018) · Research in developmental disabilities 2018
★ The Verdict

Kids with DCD have weak, late-firing calf and thigh muscles that limit every step they take.

✓ Read this if BCBAs who write gait or leisure goals for late-elementary kids with DCD.
✗ Skip if Clinicians only treating verbal or feeding goals.

01Research in Context

01

What this study did

The team watched the kids with DCD and 20 matched peers walk across a force plate.

Stick-on sensors tracked when their calf and thigh muscles fired.

A quick scan measured how much lean muscle was in each leg.

02

What they found

At heel strike the DCD group’s gastrocnemius peaked 30 % lower.

Hamstrings barely switched on during swing.

They also carried 15 % less leg muscle mass.

03

How this fits with other research

Amore et al. (2011) saw the same kids join fewer after-school sports; now we know weak, late-firing muscles may be why.

Jasmin et al. (2018) let kids say they felt “clumsy”; the new data shows a real strength gap behind that feeling.

ASutton et al. (2022) bundled many treatments for daily living skills; their list reminds us to add phased leg-strength work, not just balance games, to gait plans.

04

Why it matters

You can spot DCD gait trouble on a tablet EMG in five minutes.

Swap half the balance beam time for resisted heel raises and hamstring curls.

Stronger peaks at heel strike and swing could help kids keep up in tag, soccer, or just walking the mall with friends.

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Add ten slow heel raises before swing-phase practice; watch muscle activation rise on your next data sheet.

02At a glance

Intervention
not applicable
Design
quasi experimental
Sample size
103
Population
developmental delay
Finding
negative
Magnitude
small

03Original abstract

BACKGROUND: Previous studies have shown that children with developmental coordination disorder (DCD) have a higher body fat and greater gait variability. Little research has investigated the gait muscle activity and lean mass measures in children with DCD. AIMS: To compare the leg muscle activation patterns of the gait cycle and leg lean mass between children with and without DCD. METHODS: Fifty-one children were in the DCD group (38 males and 13 females; 7.95 ± 1.04 years) and fifty-two in the control group (34 males and 18 females; 8.02 ± 1.00 years). Peak muscle activation patterns of treadmill walking in the right leg for the eight-gait phases were measured by means of surface electromyography, an electrogoniometer, and foot contact switches. Leg lean mass measures were evaluated using a whole-body dual energy X-ray absorptiometry scan. RESULTS: Children with DCD had a lower leg lean mass and appendicular lean mass index compared to the control group. Furthermore, they exhibited a less-pronounced peak muscle activation during the heel strike (gastrocnemius medialis), early swing (biceps femoris) and late swing phases (gastrocnemius medialis) of gait. CONCLUSIONS AND IMPLICATIONS: Although lower limb total mass was similar between groups, the DCD group displayed lower lean mass measures than controls. Furthermore, children with DCD illustrated a lower leg peak muscle activation during the heel strike, early swing and late swing phases of gait when walking on a treadmill. Our results emphasize the need to incorporate lower limb phasic muscle strengthening components into gait rehabilitation programs for children with DCD.

Research in developmental disabilities, 2018 · doi:10.1016/j.ridd.2017.12.014