Handgrip test reflects breathing muscle strength in adults with cystic fibrosis
Study suggests a simple measure could complement lung function testing
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Handgrip strength was associated with breathing muscle strength in adults with cystic fibrosis (CF), according to a new study, suggesting the simple test may help complement standard lung function tests in clinical care.
The research also found that lung function and breathing muscle strength were related to a combination of factors, including handgrip strength, physical activity, resistance training, and body weight, with some notable differences between men and women.
“These results suggest that [handgrip strength] may serve as a clinically feasible marker associated with inspiratory muscle strength in [CF],” the researchers wrote.
New study explores muscle strength and breathing in CF
The study, “Peripheral muscle strength and lung function in adults with cystic fibrosis,” was published in Respiratory Medicine.
People with CF often face challenges beyond lung disease, including weakened limb muscles and reduced exercise capacity. These problems have been linked to factors such as physical inactivity, poor nutrition, and chronic inflammation.
Handgrip strength testing, performed using a small handheld device called a dynamometer, is a simple, non-invasive way to measure overall muscle strength. Previous research suggests it reflects overall muscle mass and physical function and may also relate to lung health.
Although earlier studies have found links between handgrip strength and inspiratory muscle strength — the muscles used for breathing — in other patient groups, this relationship had not been previously studied in adults with CF.
To address this gap, the team recruited 155 adults with CF, ages 18-64, with a mean age of 35.4 years. About half (51%) were women. All participants were clinically stable and able to complete lung function and handgrip strength testing. More than half (61%) were physically active, primarily men, and almost 90% were receiving CFTR modulator therapy — most commonly Trikafta (elexacaftor/tezacaftor/ivacaftor).
Simple handgrip test compared with lung and breathing measures
Handgrip strength was measured using a digital Jamar dynamometer. Lung function was evaluated using two standard tests: FEV1, which measures how much air a person can forcefully exhale in one second, and FVC, the total amount of air exhaled. Inspiratory muscle strength was assessed by measuring maximal inspiratory pressure, which reflects how strongly a person can inhale against resistance after fully exhaling.
Analysis showed a weak but statistically significant association between peak handgrip strength and FVCpp, a measure that compares a person’s lung function with expected values based on age, height, sex, and ethnicity.
In women, but not in men, better lung function was independently associated with combinations of factors that included stronger handgrip strength, higher body mass index (BMI), greater weekly physical activity, and more resistance training.
No direct association was found between handgrip strength alone and FEV1pp. However, in women — but again not in men — lung function was associated with combinations of factors, including handgrip strength and BMI, BMI and physical activity, and handgrip strength, BMI, and weekly exercise.
Men showed higher inspiratory muscle strength than women overall. In men, stronger handgrip strength was significantly associated with stronger breathing muscle strength, but the association was not observed in women.
Results show key differences between men and women
After adjusting for BMI, physical activity, and resistance training, the researchers found that in men, both handgrip strength and resistance training were associated with stronger inspiratory muscle strength. No similar associations were seen in women.
Differences in exercise levels between men and women may have contributed to the greater peripheral and inspiratory muscle strength observed in men, the team noted.
“This study contributes novel evidence linking peripheral muscle strength with inspiratory muscle strength in adults with CF,” the researchers wrote. “In contrast, its utility as an indicator of spirometric pulmonary function appears more limited.”
