Cardiorespiratory of land and water walking on a non motorized treadmill.

AIM: This study was designed to assess submaximal cardiac and pulmonary demand imposed by walking on a non motorized treadmill in land and in water condition. METHODS: Eight healthy young subjects (mean age, body mass and height: 26.5 ± 2.8 years; 66.7 ± 9.60 kg; 172 ± 8.07 cm) performed one maximal treadmill running test on land and a submaximal incremental test (treadmill speed 2, 3, 4 km.h-1; 5 minutes step duration; 15 minutes total duration) in land (L) at 2, 3, 4 km.h-1 (L2, L3, L4) and in water (W) at 2, 3, 4 km.h-1 (W2, W3, W4). Individual stride frequency at any given submaximal walking speed on land was used to perform comparable water tests. Heart rate (HR) and oxygen consumption (VO2) were continuously measured during the tests. RESULTS: Rest heart rate (%max) decreased immediately after water immersion [land HR(%max) 42 b.min-1±3; water HR(%max) 36 b.min-1 ± 5, P<0.05] while the other physiological parameters were comparable between land and water condition [land VO2(%max) 9.44 mL.Kg.min-1 ± 1.54; water VO2(%max) 7.75 ml.Kg.min-1 ± 2.4, p>0.05; land ventilation [VE(%max)] 8.71 L.min-1 ± 2.37; water VE(%max) 7.67 L.min-1 ± 2.79, p>0.05; land respiratory exchange ratio (RER) 0.77 ± 0.5 water RER 0.75 ± 0.07, P>0.05]. During exercise at 2, 3 and 4 Km.h⁻¹, reserve heart rate [HRR (%max)] was higher during water walking (W2 35 ± 10; W3 54 ± 11; W4 76 ± 9 b.min⁻¹) than during land walking (L2 23 ± 5; L3 39 ± 7; L4 58 ± 8 b.min-1, P<0.05). VO2and VE were not different. CONCLUSION: The findings suggest that water walking on a non motorized treadmill elicits similar VO2but higher HR than land walking; this factor should be considered when prescribing exercise intensity in water using heart rate.

Cardiac and metabolic demands of in place shallow water running in trained and untrained men.

AIM: The aim of this study was to assess maximal cardiac and metabolic demand imposed by in place shallow water running (SWR) and to compare such responses with those obtained during treadmill running (TMR). METHODS: Twelve males, 6 trained (T) pentathletes (age: 19+/-1 years) and 6 untrained (UT) controls (age: 22+/-1 years), performed one maximal TMR test and one SWR maximal test. Heart rate (HR) and oxygen consumption (VO(2)) were continuously measured in both test conditions. RESULTS: In both groups, resting HR decreased immediately after water immersion (UT group: from 81.8+/-6.2 b x min(-1) to 69.2+/-6 b min(-1); T group: from 71.7+/-2.1 b x min(-1) to 61.7+/-7.7 b x min(-1)). In UT subjects SWR metabolic demand was comparable to that obtained during treadmill (VO(2tmr)=47.9 ml min(-1)+/-3.6; VO(2tmr)=45.2 ml x min(-1) +/- 6.8). In contrast, during shallow SWR, T subjects obtained lower V.O(2max) values with respect to TMR (V.O(2tmr)=68.9 mL x min(-1) +/-5.1; VO(2TMR)=57.2 mL x min(-1)+/-3.9; P<0.05). In the T group maximal HR was lower during SWR (from 191+/-8.1 to 177+/-7.1). At a given stride frequency, SWR was less demanding than treadmill in terms of V.O(2) and HR responses. During SWR the metabolic adjustments were depressed more than the cardiac adjustments. CONCLUSION: These findings suggest that in place SWR may be a useful exercise to reduce the effects of detraining.

[A preliminary investigation on the occurrence of protozoa in swimming pools in Italy]. / Ricerca di protozoi nelle acque di piscina in Italia: risultati di un'indagine preliminare.

In Italy controls on the hygienic quality of swimming pools are fixed by the Accordo tra il Ministero della Salute, le regioni e le province autonome di Trento e di Bolzano, come into force in 2003. In the present study swimming pools were investigated from the microbiological point of view on the basis of the new legislation. Contemporaneously, for the first time in Italy, analytical controls on the occurrence of the protozoa Cryptosporidium and Giardia were performed with both techniques of immunofluorescence and polymerase chain reaction. Results evidenced a good water quality when the bacterial parameters stated by law were considered. However in some swimming pools, the protozoa were also recovered. Factors affecting the use of molecular techniques on the analysis of environmental samples are also put into evidence.