A new study demonstrates the utility and practicality of the 1-minute sit-to-stand test (1STST) in identifying and monitoring muscle weakness in patients with cystic fibrosis (CF).

The study, published in Respiratory Research, found that the reduction in 1STST among patients correlated well with the maximal isometric voluntary contraction of the quadriceps (MVCQ) and with forced expiratory volume in 1 second (FEV-1).

“Quadriceps muscle weakness and reduced exercise tolerance are prevalent in cystic fibrosis and are independent factors of mortality,” the authors wrote. “The primary objective of our study was to evaluate quadriceps muscle strength and functional exercise capacity in stable patients with CF, with the 1STST and the dynamometer.”

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The research team assessed 51 patients with stable CF and 30 patients receiving intravenous (IV) antibiotics at a single center between February 2017 and October 2019. The 1STST and a Microfet2 dynamometer for measuring MVCQ were prospectively employed at routine patient visits, and before and after IV antibiotic therapy.

The results show a dramatic reduction in MVCQ as measured by the dynamometer, as well as a reduced 1STST in stable patients with CF compared with the general population. The authors found the 1STST to be a reliable alternative to the dynamometer in assessing quadriceps force in the patients, with an advantage over the dynamometer of also assessing functional exercise capacity. In addition, the 1STST showed a moderate correlation with disease severity as determined by FEV-1.

In the patients on IV antibiotics, there was a reduced 1STST and MVCQ at the start of the therapy, with an increase in 1STST after the therapy. The improved 1STST was significantly better when the treatment was done at a hospital rather than at home.

The authors conclude that the 1STST is effective in detecting and monitoring muscle weakness in patients with CF and they recommend its routine use, especially given that muscular strength and exercise capacity are important prognostic indicators in CF.

Reference

Hardy S, Berardis S, Aubriot AS, Reychler G, Gohy S. One-minute sit-to-stand test is practical to assess and follow the muscle weakness in cystic fibrosis. Respir Res. Published online September 23, 2022. doi:10.1186/s12931-022-02176-6