Maarten van Egmond

70 Chapter 4 Figure 1. CT scans at the third lumbar vertebra level of a male patient with normal skeletal muscle mass (right) and decreased muscle mass (left) Skeletal muscle surface areas are highlighted in red. By international consensus, we considered people sarcopenic if the total muscle tissue area measured at the third lumbar level (L3) was less than 52.4 cm 2 /m 2 body surface area for men and 38.5 cm 2 /m 2 for women measured with CT imaging. 17 Muscle strength We measured the highest value of handgrip strength (HGS) on the right and left side with the Jamar ® grip strength dynamometer (Lafayette Instrument Company, Lafayette, USA). This dynamometer is a reliable instrument to predict the total skeletal muscle strength. 25-28 We calculated the percentage HGS of predicted by using normative values for adults, taking gender, age, height and measurement side into account. 29 We measured maximal inspiratory and expiratory pressure (MIP/ MEP) as indicators of respiratory muscle strength reporting the highest value, with a micro-medical spirometer (Micro-RPM, Micro Medical Ltd., Rochester, England). These measurements are described as valid and reliable. 25,30 We calculated the percentage MIP and MEP of predicted by using normative values, predicted by a regression equation based on age, gender and height. 31 We assessed functional lower extremity strength with the 30-second chair stand test (30CST). During this test, the patient had to stand up from a chair without support of the arms and sit again, repeating this during 30 seconds, registered as counts. This test was validated and reliable in older adults. 25,28,32 We described normative values for men and women older than 60 years old. 33