Sarcopenia parameters in active older adults - an eight-year longitudinal study

BACKGROUD: Sarcopenia is a common skeletal muscle syndrome that is common in older adults but can be mitigated by adequate and regular physical activity. The development and severity of sarcopenia is favored by several factors, the most influential of which are a sedentary lifestyle and physical inactivity. The aim of this observational longitudinal cohort study was to evaluate changes in sarcopenia parameters, based on the EWGSOP2 definition in a population of active older adults after eight years. It was hypothesized that selected active older adults would perform better on sarcopenia tests than the average population. METHODS: The 52 active older adults (22 men and 30 women, mean age: 68.4 ± 5.6 years at the time of their first evaluation) participated in the study at two time points eight-years apart. Three sarcopenia parameters were assessed at both time points: Muscle strength (handgrip test), skeletal muscle mass index, and physical performance (gait speed), these parameters were used to diagnose sarcop0enia according to the EWGSOP2 definition. Additional motor tests were also performed at follow-up measurements to assess participants' overall fitness. Participants self-reported physical activity and sedentary behavior using General Physical Activity Questionnaire at baseline and at follow-up measurements. RESULTS: In the first measurements we did not detect signs of sarcopenia in any individual, but after 8 years, we detected signs of sarcopenia in 7 participants. After eight years, we detected decline in ; muscle strength (-10.2%; p < .001), muscle mass index (-5.4%; p < .001), and physical performance measured with gait speed (-28.6%; p < .001). Similarly, self-reported physical activity and sedentary behavior declined, too (-25.0%; p = .030 and - 48.5%; p < .001, respectively). CONCLUSIONS: Despite expected lower scores on tests of sarcopenia parameters due to age-related decline, participants performed better on motor tests than reported in similar studies. Nevertheless, the prevalence of sarcopenia was consistent with most of the published literature. TRIAL REGISTRATION: The clinical trial protocol was registered on ClinicalTrials.gov, identifier: NCT04899531

Energy Cost of Human Locomotion on Land and in Water

Maximal absolute speeds in human locomotion range from a minimum of about 7km?h-1 in swimming (100m free style) to over 70km?h-1 in cycling (200m with a flying start), whereas the maximal muscular power of elite athletes competing in these events is essentially equal. Hence these large speed differences depend on the specific characteristics of each form of locomotion. These will be described in some detail with the aim of providing a comprehensive overview of the resulting energy cost of transport under different sets of conditions, such as constant versus accelerated or decelerated speed, uphill versus downhill slopes, the effects of barometric pressure, and of the characteristics of the terrain. The resulting overall picture can be condensed in a limited number of equations allowing us to predict overall energy expenditure as well as maximal speed in the locomotion considered, provided that a few parameters concerning the subject and the environmental conditions in question are known

Factors limiting maximal O2 consumption: effects of acute changes in ventilation

The response of the O2 transport system to acute changes in alveolar ventilation (VA) was analysed. The fractional limitations to maximal O2 consumption (VO2max) imposed by the lungs (ventilation, FV, and lung-blood transfer, FL), the cardiovascular system (FQ), and peripheral O2 diffusion (Fp) were calculated according to a multifactorial model. A reference set of data, describing the status of O2 transport at maximal exercise in normoxia was used. The effects of VA on VO2max were assessed on the assumption of a constant reference O2 flow in mixed venous blood (QVO2). The changes in reference data after given independent changes in VA were calculated by an iterative procedure, until the VO2max value compatible with the constant reference QVO2 was found, at PIO2 values of 150 (normoxia), 130, 110 and 90 Torr. The VO2max changes in normoxia were less than expected assuming a linear O2 transport system, because of the flatness of the O2 dissociation curve around normoxic PO2. This affected the cardiovascular resistance to O2 flow, and its changes counterbalanced the effects on VO2max of induced changes in VA. This phenomenon was reversed in hypoxia, as the steep part of the O2 dissociation curve was approached. The fractional limitations to VO2max in normoxia resulted as follows: FV and FL provided between 5 and 12%, FQ between 59 and 78%, and Fp between 13 and 19% of the overall VO2max limitation. In hypoxia, FV and FL increased and FQ decreased. At PIO2 = 90 Torr, when VA was halved, FV, FL, FQ and Fp amounted to 0.35, 0.31, 0.20 and 0.14, respectively

Mechanical efficiency of cycling with a new developed pedal-crank

The mechanical efficiency of cycling with a new pedal-crank prototype (PP) was investigated during an incremental test on a stationary cycloergometer. The efficiency values were compared with those obtained, in the same experimental conditions and with the same subjects, by using a standard pedal-crank system (SP). The main feature of this prototype is that its pedal-crank length changes as a function of the crank angle being maximal during the pushing phase and minimal during the recovery one. This variability was expected to lead to a decrease in the energy requirement of cycling since, for any given thrust, the torque exerted by the pushing leg is increased while the counter-torque exerted by the contra-lateral one is decreased. Whereas no significant differences were found between the two pedal-cranks at low exercise intensities (ẇ=50-200W), at 250-300W the oxygen uptake (V̇O2, W) was found to be significantly lower and the efficiency (η=ẇ/V̇O2) about 2% larger (p&lt;0.05, Wilcoxon test) in the case of PP. Even if the measured difference in efficiency was rather small, it can be calculated that an athlete riding a bicycle equipped with the patented pedal-crank could improve his 1h record by about 1km. © 2002 Elsevier Science Ltd. All rights reserved