To clarify whether 4 weeks of standing exercise combined with LV increases muscle thickness of disused, atrophied triceps surae and physical functions compared to standing without LV.
Among the patients admitted to the community integrated care ward, 24 patients who met the criteria for intensive care unit-acquired weakness were defined as having disuse syndrome. After stratification by age, participants were randomly assigned to either group as described below. In addition to the usual physical therapy, the intervention consisted of five sets of 30-second standing exercises per day, 5 days/week, for 4 weeks while grasping support (standing-only group, 12 patients; non-vibration group; NV). A massager was wrapped around the gastrocnemius muscles of both lower legs, allowing a 57 Hz oscillator to target the abdomen while participants maintained a standing position (group with concomitant LV; 12 patients; LV group). The pre-and post-intervention evaluation items were as follows: muscle thickness of the lower leg, range of motion (ROM) of ankle dorsiflexion, maximum isometric strength of the plantar flexor, muscle activity of the medial gastrocnemius, skeletal muscle index, motor functional independence measure (FIM) score, activities of daily living assessment, and functional mobility. Muscle thickness was measured at eight locations inside and outside of the participant's dominant leg in the gastrocnemius and soleus muscles. The reference point was defined as the proximal 30% of the distance from the medial knee joint line to the medial malleolus. The muscle thicknesses at the eight locations were added together and termed total muscle thickness (TMT). Statistical analysis considered missing data and a generalized linear mixed model was employed to examine changes between groups and after intervention.
All 12 patients in each group completed the intervention. The intervention compliance rate was 100% in both groups. A significant interaction was observed for TMT (p 0.02), with an increase in TMT observed only in the LV group. Significant main effects were observed in ROM, maximum isometric strength, motor FIM score, gait speed, maximum standing time, and SPPB score, all of which improved after the intervention period. No other significant outcomes were observed.
Standing exercise for 4 weeks in combination with LV may promote muscle hypertrophy of triceps surae in older adults with disuse-induced skeletal muscle atrophy compared to normal standing exercise.
By using LV during exercise, obtaining a muscle hypertrophy effect in older adults with disuse syndrome may be possible. Ultrasonographic assessment of muscles in clinical settings allows for a more accurate understanding of local muscle mass, as opposed to total-body skeletal muscle mass.
disuse-induced muscle atrophy
muscle thickness
