Performances of handgrip strength with persons seated in a chair or bed are comparable when conducted in an acute hospital.

The purpose of the study was to investigate the criterion validity of HGS measured in a chair with armrests versus a bed in an acute care hospital setting.

Participants were recruited equally across three hospital wards (orthopaedic, medical, and geriatric), and were randomly assigned to start the HGS testing either seated in a bed with a pillow supporting the test-arm (dominant hand) or in a chair with armrests. The elbow was in 90-degree flexion, the wrist in neutral position and the hand free of the pillow/armrest. Participants were instructed to squeeze as hard as possible on the handle for aproximately 5 seconds and were given three attempts (30 second rest between each) in both positions with a 5-minute break in between. The physiotherapist instructing participants was blinded to all results until all had been tested. The highest HGS value from both position was used for analysis. Statistical analysis included the paired t-test, Intraclass Correlation Coefficient (ICC 2.1), Bland-Altman plot, Standard Error of Measurement (SEM), and Minimal Detectable Change (MDC). The Baseline BIMS Digital HGS dynamometer was used for all testing.

Sixty persons (34 women) with a mean (SD) age of 76.5 (15.1) years, and a Body Mass Index of 24.7 (4,9 SD) kg/cm² were included. Before admission, 30 of participants used a walking aid and 25 had some level of home care. The average HGS of performances in bed and chair was 23.7 (9.1) kg, with no systematic difference (mean of 0.023 kg, 95% CI -0.51, 0.47; p = 0.92) between performances in both positions, but slightly favouring the chair position. The ICC-score was 0.98 (95% CI 0.96, 0.99; p 0.001), the Bland-Altman plot showed a limit of agreement of ±3.7 kg, while SEM and MDC were 0.27 kg and 0.76 kg, respectively.

An excellent agreement with low measurement error was found between the bed and chair positions for measuring HGS across wards in an acute care hospital setting. 

Our findings indicate that performances of HGS conducted in a hospital bed or a chair with armrests are comparable and can be used interchangeably supporting its broader use by physiotherapists in clinical settings and research.