Muscle morphology, enzymatic activity, and muscle strength in elderly men: A follow‐up study

TLDR

The cohort comprised 23 clinically healthy men aged 73–83 with no locomotor disturbances, aside from a few with heart failure or hypertension. The study followed these men for seven years, reassessing muscle strength, morphology, and enzymatic activity in the quadriceps and biceps brachii. Over the 7‑year period, body weight fell 2 % and body cell mass 6 %, quadriceps strength declined 10–22 %, fast‑twitch fiber areas in the vastus lateralis reduced, histopathologic changes increased there, while lactate dehydrogenase and myokinase activities remained stable and overall metabolic capacity was preserved, with oxidative activity higher in the vastus lateralis and glycolytic activity higher in the biceps brachii.

Abstract

Abstract A follow‐up study of muscle strength, muscle morphology, and enzymatic activity in 23 men, 73–83 years of age, was performed 7 years after the first investigation. With the exception of two men treated for congestive heart failure and four treated for hypertension, all were apparently clinically healthy and none had functional locomotor disturbances. Body weight was reduced by 2% and body cell mass by 6%, whereas the quadriceps muscle strength decreased 10%–22% over the 7‐year period. Fiber composition in the vastus lateralis did not change significantly, and there was no significant difference between the biopsies from the biceps brachii and vastus lateralis. In the vastus lateralis, there was a reduction in fast‐twitch fiber areas, which were smaller than in the biceps brachii (not studied at the previous investigation). There were also more histopathologic changes in the vastus lateralis than in the biceps brachii. The enzymatic activities of lactate dehydrogenase and myokinase, which were studied on both occasions in the vastus lateralis, did not change, and the activities of the other measured enzymes indicated a maintained metabolic capacity at high age. Oxidative enzymatic activities were higher in the vastus lateralis, and glycolytic enzymatic activities were higher in the biceps brachii, which could partly be explained by differences in relative fiber areas.