Assessment & Research

Association of muscular strength with total and central adiposity in adolescents with intellectual disability.

Bertapelli et al. (2023) · Journal of intellectual disability research : JIDR 2023
★ The Verdict

In teens with ID, stronger muscles mean lower body fat—check strength to find who needs exercise.

✓ Read this if BCBAs writing health or fitness goals for middle- and high-school students with intellectual disability.
✗ Skip if Clinicians serving only verbal adults with no weight concerns.

01Research in Context

01

What this study did

Boswell et al. (2023) measured grip, leg, and core strength in high-school students with intellectual disability. They also recorded height, weight, waist size, and body-fat percentage.

Using simple statistics, they asked: does stronger muscle predict lower fat after accounting for sex and puberty stage?

02

What they found

Yes. Teens with the highest strength scores had the lowest BMI, body-fat, and waist size. Muscle strength explained about one-tenth to one-sixth of the differences in fat measures.

The link held for boys and girls, and for early or late maturers.

03

How this fits with other research

Thomas et al. (2021) saw the same pattern in adults: stronger grip and leg press went hand-in-hand with lower BMI. The new study shows the link is already present in adolescence.

Wu et al. (2017) went a step further. They ran a 12-week school exercise program and actually cut BMI in overweight teens with ID. F et al. give you the baseline to spot kids who need that program.

Borji et al. (2014) help explain why: people with ID often can’t fully switch their muscles on, so they start weaker. Screening strength first flags who is at risk for extra fat.

04

Why it matters

You already track behavior data. Add a 30-second grip-strength test at intake. A low score is a red flag for obesity risk and a green light for referral to PE or community sports. No extra paperwork, just one number that tells you which teens need movement goals written into their plans.

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Add a hand-grip dynamometer to your assessment kit; test each teen and flag scores below age norms for a movement intervention.

02At a glance

Intervention
not applicable
Design
other
Sample size
59
Population
intellectual disability
Finding
negative
Magnitude
medium

03Original abstract

BACKGROUND: It has been established that for youth without disabilities, muscular strength (MS) is negatively associated with total and central adiposity. However, this relationship has not been clearly established for youth with intellectual disability (ID). The purpose of this study was to examine the association of MS with total and central adiposity in adolescents with ID. METHOD: Participants were 59 adolescents (40 males and 19 females: age 16.29 ± 1.66 years) with ID. Total and central adiposity were evaluated with dual-energy x-ray absorptiometry (DXA), body mass index (BMI), BMI z-score, waist circumference (WC), and conicity index (C-index). MS was evaluated with the score on the Bruininks-Oseretsky Test of Motor Proficiency (range, 0 to 42, with higher scores indicating better performance). Sex-specific maturity offset equations were used to evaluate somatic maturity. Spearman's correlation coefficients and sequential multiple regression were used to examine associations between MS and adiposity. RESULTS: Muscular strength score was negatively associated with BMI (sr = -0.32; P < 0.05), percent body fat (%BF; total, trunk, android and gynoid regions) (sr = -0.51 to -0.58; P < 0.01), and android-to-gynoid fat ratio (sr = -0.29; P < 0.05). After control for somatic maturity and sex, regression analysis indicated that MS score explained 10%-17% of the variance in BMI, BMI z-score, %BF (total, trunk, android and gynoid regions), WC, C-index and android-to-gynoid fat ratio. CONCLUSIONS: These findings suggest that MS is associated with DXA- and anthropometric-determined total and central adiposity among adolescents with ID.

Journal of intellectual disability research : JIDR, 2023 · doi:10.1111/jir.12981