Nuria Garatachea | PubMed Health

PubMed2006

Determination and validity of critical swimming velocity in elite physically disabled swimmers.

The purpose of this investigation was to determine if the critical swimming velocity (CSV), defined as the theoretical maximal swimming velocity that could be maintained for a long period of time without exhaustion, corresponds to the exercise intensity at onset blood lactate accumulation (OBLA), and if it could be utilized as a practical index for assessing endurance performance in elite physically disabled swimmers. Eight elite physically disabled swimmers swam four different distances (50, 100, 200 and 400 m) at maximal effort. The swimming time was taken during each trial. The CSV was expressed as the slope of a regression line between the covered swimming distance and the corresponding times of all possible combinations of 2 or 4 time trials. Results indicate that all the CSVs calculated were similar independently of the distances utilized for their calculation. Afterwards, a CSV confirmation test consisting of 3 x 10-min trials at 95, 100, 105% of the CSV was carried out. The lactate concentration at the end of each trial was 3.32, 4.03 and 5.73 mmol x l(-1), respectively. Lactate concentration at 100% CSV approached the value of 4 mmol x l(-1), which is considered the exercise intensity at OBLA. We conclude that the CSV corresponds with the OBLA intensity and could be a valuable index to plan a training schedule for physically disabled swimmers.

Adult↗

PubMed2002

Ventilatory efficiency during exercise in healthy subjects.

When evaluating dyspnea in patients with heart or lung disease it is useful to measure the quantity of ventilation needed to eliminate metabolically produced CO2 (i.e., the ventilatory efficiency). Mathematically, the relationship between ventilation (VE) and CO2 output is determined by the arterial CO2 pressure and the physiologic dead space-tidal volume ratio. We decided to determine how age, sex, size, fitness, and the type of ergometer influenced ventilatory efficiency in normal subjects. Three methods were compared for expressing this relationship: (1) the VE versus CO2 output slope below the ventilatory compensation point, commonly used by cardiologists for estimating the severity of heart failure; (2) the VE/CO2 output ratio at the anaerobic threshold, commonly used by pulmonologists; and (3) the lowest VE/CO2 output ratio during exercise, the latter parameter not previously reported. We studied 474 healthy adults, between 17 and 78 years of age during incremental cycle and treadmill cardiopulmonary exercise tests at three test sites, correcting the total VE for the equipment dead space. The lowest VE/CO2 output ratio was insignificantly different from the ratio at the anaerobic threshold, less variable than that for the slope relationship, and unaffected by the site, ergometer, and gas exchange measurement systems. The regression equation for the lowest VE/CO2 output ratio was 27.94 + 0.108 x age + (0.97 = F, 0.0 = M) - 0.0376 x height, where age is in years and height is in centimeters. We conclude that the lowest VE/CO2 output ratio is the preferred noninvasive method to estimate ventilatory inefficiency.

Adult↗