Abstract des Autors

Background: The physiological aging process in the musculo-skeletal system involves both changes at the functional level and at the structural level, including changes in muscle mass, body composition, and contractile properties. Age-related decline in muscle mass and muscle function is called sarcopenia. Early attempts to define sarcopenia were only based on measurements of skeletal muscle mass in relation to body size. Meanwhile, the European Working Group on Sarcopenia in Older People (EWGSOP) recommend the use of both constructions, muscle mass and muscle function, in defining sarcopenia.In addition to reduced muscle mass, in older people an increase in fat mass is observed. The term ‘sarcopenic obesity’ (SO) has been introduced describing this metabolic situation of increased fat mass and decreased muscular function.Resistance training has been recognized as an effective method for counteracting sarcopenia. In addition to increasing strength, resistance training can also improve functional performance, activities of daily living and quality of life in elderly adults. Currently, there are no studies specifically addressing elderly adults with SO involving a particular resistance training program.Objectives The first objective was to compare the performance of elderly, obese women and men with and without sarcopenia regarding muscle mass, muscle strength and physical performance before and after resistance training. The second objective was to determine if the modalities of previous existing recommendations for resistance training for elderly, healthy adults and those with type II diabetes are transferable to elderly people with SO. The third objective was to investigate the relationships between body composition, muscle function and physical activity in elderly men with and without sarcopenia. In a next step of the analysis, the objective was to determine the factors having the greatest impact on muscle mass.
Methods: Sarcopenia was assessed using the Short Physical Performance Battery (SPPB), hand-grip strength (HGS), skeletal muscle index (SMI), and gait speed over a six-meter walkway. Furthermore, the maximum dynamic and isometric strength at leg and chest press, the modified Physical Performance Test (PPT) and the Functional Reach Test (FRT) were assessed. The participants were elderly women and men (≥ 65 years), with or without obesity (BMI ≥ or < 30 kg/m2), and without severe diseases. They were divided into groups, those with sarcopenia (SAR) and those without sarcopenia (NSAR). The intervention consisted of progressive resistance training, twice a week for 16 weeks with finally 80–85% of maximum dynamic strength and three sets with 8-12 repetitions. The training consisted of six exercises for the major muscle groups.
Results: Participants in the SAR groups significantly increased their performance in HGS, gait speed, SPPB score and modified PPT score after training. In SPPB and modified PPT, they could reach the values of the NSAR group’s baseline performance. The results showed an increase in maximum dynamic strength of the upper and lower limbs in every SAR and NSAR group. SMI did not change in either group. Training participation was over 80% on average, with a low drop-off rate of three men and four women. The correlation analysis showed strong correlations between SMI and gait speed, HGS, isometric maximum strength at leg and chest press. Regression analysis revealed HGS and gait speed as key predictors for SMI.
Discussion and Conclusion: Elderly, obese women and men with sarcopenia increased significantly their maximum strength and physical performance due to intensive resistance training. The increases in this field can support functional independence in daily life and help prevent physical impairment and falls. The previous existing recommendations for resistance training were adapted for this target group, especially a gentle beginning of the training and slower progression of the weights were necessary. Based on the results of the regression analysis, the recommendation is to first measure gait speed and HGS in clinical practice, followed by measuring muscle mass regarding the determination of sarcopenia.The increases of maximum strength and physical performance after resistance training were promising. However, the results did not show improvements in the field of muscle mass. Thus, future studies with complex interventions strategies including nutritional interventions are needed in elderly, obese adults with and without sarcopenia.