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Comparison of activity monitors accuracy to estimate energy expenditure of daily living activities
No full textAccurate assessment of the total amount of physical activity (PA) or the energy expenditure (EE) in free living condition is a big challenge. A priority has been placed on the study of valid and reliable measures for all levels of PA. New technologies are available for objectively measuring PA and inferring EE: the Actiheart -AH-(Cambridge Neurotechnology, UK) and the SenseWear Pro2 ArmbandTM -SWA-(BodyMedia, USA) are an example of these new devices.
PURPOSE The purpose of the present study was to examine the validity of these two new devices during light (<3 METS) to moderate (3-6 METS) and vigorous (>6 METS) intensity daily living activities in laboratory and feld settings.
METHODS: 8 physically active women volunteered to participate in the study and performed in two separate days different activities: resting, occupation, housework, conditioning and recreation. Oxygen consumption was measured continuously throughout the routine by indirect calorimetry -IC- (K4b2, Cosmed, Italy) and participants wore the Actiheart on the chest and the Armband on the right arm for simultaneous estimation of EE (METS). RESULTS The combined AH model (Branched model: activity counts+HR) had the strongest relationship with PAEE (r=0785, p<0001) compared with those from the single-measure models (r=.748 and .719, p<0001 for the activity model and the HR model respectively), so that we only used this equation model to compare data with SWA and IC. The two analyzed methods were highly correlated with IC (AH r=.785 and SWA r=.795, p<0001) even if PAEE expressed in METS resulted significantly different for both devices (p<0.001 for AH and p<0.001 for SWA). The positively correlated errors with measured PAEE in the plots of both AH and SWA models indicate a systematic error in these equations (mean difference between methods= AH 1.52±2.38, SWA -0.11±2.48; 95% limits of agreement= AH -3.24 to 6.28, SWA -5.07 to 4.85). On the contrary the explained variances from the AH were lower if light intensity exercises are considered. CONCLUSION The AH provides reliable estimates of EE for light intensity activities; on the contrary it underestimates moderate and vigorous activities. The SWA has a lower systematic error in moderate and vigorous exercises. Both devices can provide a valid measure of the time spent in various intensity categories
The contribution of the Italian Sport Sciences Institute in the preparation to the Vancouver Olympic Games
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A comparison of physiological responses during a CPR exercise on treadmill and a low impact aerobic dance lesson
No full textPURPOSE: Therefore our purpose was to investigate the differences of physiological responses between two aerobic exercises: Constant Pulse Training (CPR) and low impact aerobic routine (LIA) in order to understand if LIA fits the needs of overweight subjects in terms of energy substrate utilization.
METHODS: Six overweight female underwent a V'O2max incremental submaximal test (Quark b2, Cosmed, Italy). Oxygen uptake (V'O2) and heart rate (HR) were used to draw V'O2/HR relationship. Each subject also took part in two training sessions carried out over alternate days: A) CPR training on treadmill at 65%, 70% and 60% of HRmax for 10, 30 and 5 min respectively; B) LIA routine consisting of warming up phase (10 min), aerobic phase (30 min), cooling down phase (5 min). During both sessions the following parameters have been continuously monitored (K4b2, Cosmed, Italy): HR, V'O2, respiratory exchange ratio (RER).
RESULTS: Results are referred to the whole training session.
If we consider the correlation between HR and V'O2, both expressed as percent values of the maximum, linear regression line among HR and V'O during CPR never overlaps the one during LIA.CONCLUSION: Both exercise modes seem to lie in the aerobic metabolism. However energy expenditure (EE) of LIA is higher than CPR, while the relative amount of CHO is significantly higher. This should be took into account when fat burning exercises are prescribed. Besides HR seems to correlate with V'O2 (according with ACSM statement) in CPR, while the same does not occur during LIA. Therefore, HR is a reliable index of the exercise intensity during CPR training, but it could overestimate V'O2 (and EE) during LIA routine
One-year Changes in Activity and in Inactivity Objectively Measured Among Overweight and Obese Children
No full textParticipation in physical activity (PA) during childhood can help to reduce the onset of risk factors associated with ill health. Seasonal influences play a large role in determining PA behaviors. Lack of information about overweight (OW) and obese (OB) children PA and sedentary (SED) behaviors, evaluated during a whole year, has made it difficult to assess appropriate interventions. PURPOSE: The aim of this study was to objectively measure PA behavior in a sample of 6 to 14 yr-old children in order to investigate seasonal and weekly differences in PA and SED habits. METHODS: 18 OW and OB children (OW (n=8): age 10,8±1,2 yr; BMI, 21,9±1,4 kg/m2; OB (n=10): age 10±2,1 yr; BMI 25,6±3,2 kg/m2) were monitored during a whole week 4 times in a year with a Actiheart (AH) monitor (Cambridge Neurotechnology, UK), inferring time spent in sedentary (SED, 3 METs) intensity. Data presented provide a minimum of four days of 10-h valid recording per week (at least 1 weekend day is included). A Repeated measure ANOVA was used to analyse data and significance was set at p<0,05. RESULTS: A non significant seasonal difference was detected for time spent in MVPA (spring 129,7±82,4; summer 106,7±76,9; fall 93,5±72; winter 82,7±60,3 min/day) causing, on the contrary, a significant seasonal difference in activity energy expenditure (AEE: spring 660,5±188,3; summer 540,8±132,1; fall 538,9±152,5; winter 482,2±136,2 kcal/day; p<0,05). A significant seasonal difference was found in SED behavior (spring 436,9±95,6; summer 389,7±81,2; fall 479,2±93,3; winter 473,8±80,1 min/day; p<0,05). No significant differences appeared between weekly and weekend days (MVPA: weekdays 100,7±70,1; weekend 110,1±87,8; SED: weekdays 460,6±94,8; weekend 431,6±118,9 min/day). Besides, OW appeared to be more active than OB children (MVPA: OW 122,8±86,2; OB 87,3±60,8 min/day, p<0,05). CONCLUSIONS: The main finding of this study is that AH data, taking activity into account (without loosing water sports or activity), indicate that for OW and OB children activity levels are highest in spring, drop in summer and reach the lowest point in winter. Besides, children do not result to be more active on weekly days than during the weekends as reported by some authors.
Kristensen PL et al. Scand J Med Sci Sports. 2008 Jun;18(3):298-308
Physiological and psychological effects of a physical activity program in a group of elderly people
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Functional model of italian ice hockey
No full textIt is actually accepted that, because of the shifts’ high intensity, hockey players require to develop muscle strength, anaerobic power and anaerobic endurance; the duration of the game and the need to quickly recover also demands a good aerobic system. The functional model of ice hockey has been particularly studied in United States and Canada; on the contrary physiological qualities of European ice hockey players are not well known.
Therefore the purpose of this study is to verify the actual energy expenditure of Italian ice hockey and the actual physiological qualities of ice hockey players.
18 ice hockey players (age 25.54.9 years; fat mass 14.02.9 %), belonging to a middle rank club of Italian premier league championship, volunteered to participate in the study and underwent both laboratory and field tests:
incremental test to exhaustion on a cycle-ergometer (Bikerace, Technogym, Italy) in order to identify maximal oxygen consumption (V’O2max) and lactate anaerobic threshold (LAT) on breath by breath basis (K4b2, Cosmed, Italy);
modified repeated sprint skate test (RSS), in order to calculate anaerobic power and capacity; peak blood lactate concentration (LApeak) was measured at the end of the test (Biosen 5030, EKF, Germany).
Moreover 3 players played a simulated on-ice hockey match during which oxygen consumption (V’O2) and heart rate (HR) were continuously monitored (K4b2, Cosmed, Italy), while blood lactate (LA) was detected at baseline and every 2 min (Biosen 5030, EKF, Germany). They were also observed during a whole match by means of a camera in order to analyze all shifts and the sprints performed during each shift (a sprint was considered a speed higher than 7 m/sec).
Physiological parameters of the studied hockey team are statistically lower for V’O2max (14%), anaerobic power (40%) and capacity (30%) if compared with USA ice hockey players (see figure 1 and 2).
The players performed for 6.03±0.49min of a 20-min game. Each shift lasts 54.07±5.27sec with an average of 7 shifts per game. V’O2 during the shifts reached 72.84±12.32% of V’O2max with average values (shifts and recovery) of about 56.56±5.01% of V’O2max. Blood lactate remained elevated above resting values (average LA 4.98±0.74mM) with peak values of about 6.87±1.45mM.
These preliminary results on Italian ice hockey players demonstrate that they possess lower physiological qualities if compared with elite American ice hockey players. Such a difference can be partly explained by the fact that the studied players don’t practice any specific off-ice training session to enhance aerobic or anaerobic components. Besides the energy demand of the game doesn’t seem high enough to stimulate to the maximum extent and in the optimal required amount both aerobic and anaerobic energy systems.
Not taking into consideration the technical and tactical abilities, it could be concluded that low physiological qualities are the main limiting factors of Italian ice hockey players. Therefore attention should be given to the physical preparation both on-ice and off-ice
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