RESUMO
Pulmonary oxygen uptake (VËO2) kinetics and heart rate kinetics are influenced by age and fitness. Muscular VËO2 kinetics can be estimated from heart rate and pulmonary VËO2. In this study the applicability of a test using pseudo-random binary sequences in combination with a model to estimate muscular VËO2 kinetics was tested. Muscular VËO2 kinetics were expected to be faster than pulmonary VËO2 kinetics, slowed in aged subjects and correlated with maximum VËO2 and heart rate kinetics. 27 elderly subjects (73±3 years; 81.1±8.2 kg; 175±4.7 cm) participated. Cardiorespiratory kinetics were assessed using the maximum of cross-correlation functions, higher maxima implying faster kinetics. Muscular VËO2 kinetics were faster than pulmonary VËO2 kinetics (0.31±0.1 vs. 0.29±0.1 s; p=0.004). Heart rate kinetics were not correlated with muscular or pulmonary VËO2 kinetics or maximum VËO2. Muscular VËO2 kinetics correlated with maximum VËO2 (r=0.35; p=0.033). This suggests, that muscular VËO2 kinetics are faster than estimates from pulmonary VËO2 and related to maximum VËO2 in aged subjects. In the future this experimental approach may help to characterize alterations in muscular VËO2 under various conditions independent of motivation and maximal effort.
Assuntos
Teste de Esforço , Pulmão/fisiologia , Músculo Esquelético/fisiologia , Consumo de Oxigênio/fisiologia , Idoso , Aptidão Cardiorrespiratória , Frequência Cardíaca , Humanos , CinéticaRESUMO
BACKGROUND: At present, it is unclear whether older, obese persons with or without sarcopenia respond differently to training. Furthermore, there are no differentiated recommendations for resistance training for this special target group. OBJECTIVES: The objectives are to investigate the changes in the physical parameters of older, obese men caused by training and to reappraise the modalities of resistance training for older persons. DESIGN: Pre-test-post-test design. PARTICIPANTS: The participants were 33 physically inactive and obese older men (≥ 65 years, BMI ≥30 kg/m2), with-out severe diseases. Subjects were divided into two groups: NSAR (no or presarcopenia, n= 15) or SAR (sarcopenia, n= 18). INTERVENTION: The intervention consisted of progressive resistance training, twice a week for 16 weeks with finally 80-85% of maximum strength and three sets with 8-12 repetitions. The training contained six exercises for the major muscle groups. MEASUREMENTS: Sarcopenia was assessed using the Short Physical Performance Battery (SPPB), hand-grip strength, skeletal muscle mass index (SMI), and gait speed over a 6-meter walkway. Furthermore, the maximum dynamic strength (1 RM) was assessed. RESULTS: At baseline, the NSAR group had significantly better values in SMI, SPPB score, hand-grip strength, and 1 RM. After training, the results in both groups displayed an increase in 1 RM at the lower limbs (NSAR 18%, SAR 38%) and the upper limbs (NSAR 12%, SAR 14%). Also, the SPPB score (NSAR 11%, SAR 15%) and the 6-m-gait speed (NSAR 5%, SAR 10%) increased. The SAR group was able to increase their right hand-grip strength by 12%, whereas the NSAR group maintained their initial high strength values. SMI did not change in both groups. CONCLUSIONS: Both groups show improvements after resistance training with slightly more benefits for men with sarcopenia. Results of this study can be used to define specific training regimens for N(SAR) subjects.