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Updated: Feb 21, 2026

Manual Muscle Testing: A Method of Measuring Extremity Muscle Strength Applied to Critically Ill Patients
Published on: April 12, 2011
Feasibility and Reliability of Functional Muscle Tests in Lung Transplant Recipients
Thomas Kienbacher1, Grace Achim-Gunacker, Melanie Pachner
1From the Karl Landsteiner Institute of Outpatient Rehabilitation Research, Vienna, Austria (TK, RH); Department of Physical Medicine and Rehabilitation, Vienna Medical University, Vienna, Austria (GA-G, MP, KK-S, GE); Department of Solid State Physics, Vienna Technical University, Vienna, Austria (PG); Department of Thoracic Surgery, Vienna Medical University, Vienna, Austria (WK, PJ); and Department of Surgery, Wilhelminen Hospital, Vienna, Austria (SD).
Objective:
This study investigates the feasibility, reliability, and correlations of recommended functional tests in lung transplant recipients shortly after surgery.
Design:
This is an observational study.
Methods:
Fifty patients (28 females) performed well-standardized maximum isometric back extension in a sitting position, handgrip strength, and Biering-Sørensen endurance tests shortly before discharge from the acute hospital, shortly thereafter, and 2 mos later after subacute rehabilitation.
Results:
Back extension testing was well feasible, but only two thirds of the patients could perform the Biering-Sørensen test at baseline and they experienced a greater number of minor but no major adverse events. Absolute reliability measures and the intraclass correlation coefficients were excellent for the strength (0.97-0.98 [0.95-0.99]) and good for the endurance tests (0.69 [0.26-0.87]). Handgrip revealed high correlation with back strength (≥0.75) but not with Biering-Sørensen scores.
Conclusions:
Well-controlled maximum back strength testing is feasible and reliable, and the scores are highly correlated with grip strength in lung transplant recipients shortly before hospital discharge. The Biering-Sørensen test should be limited to patients without dominant weakness and/or fear. Future research should investigate whether grip instead of back extension strength can safely be used for proper exercise prescription.

