Biomedical subjects

Franco M Impellizzeri

Publications and source records attributed to Franco M Impellizzeri.

10 recordsLinked to original sources

PubMed2007

The physiology of mountain biking.

Mountain biking is a popular outdoor recreational activity and an Olympic sport. Cross-country circuit races have a winning time of approximately equal 120 minutes and are performed at an average heart rate close to 90% of the maximum, corresponding to 84% of maximum oxygen uptake (VO2max). More than 80% of race time is spent above the lactate threshold. This very high exercise intensity is related to the fast starting phase of the race; the several climbs, forcing off-road cyclists to expend most of their effort going against gravity; greater rolling resistance; and the isometric contractions of arm and leg muscles necessary for bike handling and stabilisation. Because of the high power output (up to 500W) required during steep climbing and at the start of the race, anaerobic energy metabolism is also likely to be a factor of off-road cycling and deserves further investigation. Mountain bikers' physiological characteristics indicate that aerobic power (VO2max >70 mL/kg/min) and the ability to sustain high work rates for prolonged periods of time are prerequisites for competing at a high level in off-road cycling events. The anthropometric characteristics of mountain bikers are similar to climbers and all-terrain road cyclists. Various parameters of aerobic fitness are correlated to cross-country performance, suggesting that these tests are valid for the physiological assessment of competitive mountain bikers, especially when normalised to body mass. Factors other than aerobic power and capacity might influence off-road cycling performance and require further investigation. These include off-road cycling economy, anaerobic power and capacity, technical ability and pre-exercise nutritional strategies.

Bicycling↗

PubMed2006

Analysis of physical match performance in English Premier League soccer referees with particular reference to first half and player work rates.

The aim of the present study was to examine the influence of first half activity, overall match intensity and seasonal variation on the physical match performances of English Premier League football referees. Match analysis data was collected using the Prozone match analysis system from 19 full-time professional referees during a total of 254 matches in the 2004-2005 season. Physical match performances were classified into three separate categories: 1, total distance covered (TD); 2, high-intensity running distance (running speed>5.5m/s, HIR); 3, average distance from infringements (DI). Using these match activity variables the influence of first half TD and HIR distances on second half activities and also the influence of players' match activities upon the referees' physical match performances were examined. The main finding of the present study was that the physical match performances of the referees were partly related to those of the players, in that the referees' HIR correlated with players' HIR (r=0.43, p<0.0001, n=212). Furthermore, first half TD and HIR distances were found to be related to second half coverage in referees (r=0.47 and r=0.52, respectively, p<0.001, n=254). These results demonstrate a need to assess the overall match intensity prior to examining the physical match performance of the referee. Further examination is required as to whether reduced physical performances in the second half of matches are a consequence of referee fatigue, tactical strategies on behalf of the referee or reduced player match activities resulting in a slower tempo of match.

Adult↗

PubMed2006

Cardiovascular responses during recreational 5-a-side indoor-soccer.

The aims of this study were to examine the cardiovascular response to recreational 5-a-side indoor-soccer (5v5) matches (5v5 study, 5v5S, n=15) and to assess the validity of using heart rate (HR) to estimate oxygen uptake (VO(2)) demands during actual game-play (validity study, VS, n=16) in young subjects (age 16.8+/-1.5 years). Game responses during 5v5S were assessed during 30 min matches using short-range telemetry heart-rate monitors. In VS games (12 min), VO(2) and HR were monitored with a portable gas analyser (K4b(2), COSMED, Rome, Italy). Individual HR-VO(2) relationships were determined from a laboratory treadmill run to exhaustion (VS) and a multistage shuttle running fitness test (5v5S) using K4b(2). Results showed that 5v5 elicits 83.5+/-5.4 and 75.3+/-11.2% of HR(peak) and VO(2peak), respectively. Ninety-one percent of the playing time (30 min) was spent at HR higher than 70% of HR(peak). In VS match, gas analyses revealed that only 71% of HR variance was explained by VO(2) variations. However, playing at approximately 70% of HR(peak) elicited 51.6+/-11.2% of VO(2peak). Group actual versus predicted VO(2) values demonstrated no significant differences (p>0.05), however, large confidence limits were observed (+6.20 and -10.53 mlkg(-1)min(-1)). These results show that HR and VO(2) responses to recreational 5v5 soccer in young athletes are similar to the exercise intensities recommended by ACSM for promoting cardiovascular health and suggest that HR is valid to prescribe and monitor aerobic intermittent exercise. These results also show that HR measures are acceptable for estimating VO(2) during intermittent exercise when assessing large groups, but show that large estimation errors can occur at the individual level.

Adolescent↗

PubMed2006

Cardiorespiratory responses to Yo-yo Intermittent Endurance Test in nonelite youth soccer players.

This study examined the validity of the Yo-yo Intermittent Endurance Test (Level 1; YYIET) as indicator of aerobic power in youth soccer players. Cardiorespiratory responses were determined in 18 moderately trained nonelite youth soccer players (age, 16.6 +/- 0.8 years; height, 178.7 +/- 6.2 cm; body mass, 69.8 +/- 6.0 kg; VO2peak, 52.8 +/- 7.4 ml x kg(-1) x min(-1)) while performing the YYIET and an incremental treadmill test. Maximal heart rate (HRmax), respiratory exchange ratio (RER), O2 pulse, VO2peak, and maximal ventilation (VEmax) were measured. Group YYIET VO2peak, HRmax, RER, and O2 pulse were not significantly different from treadmill responses (p > 0.05). VEmax was significantly lower (p < 0.05) during the YYIET compared to the treadmill condition. No significant correlation was found between treadmill VO2peak and YYIET performance (p > 0.05). This study showed that the YYIET elicits peak VO2 and HR responses. However, YYIET performance results were not related to VO2peak measured in laboratory. Furthermore, the individual VO2peak reached during the TM did not reflect the VO2peak obtained during the YYIET, as shown by the large limits of agreement. As a consequence, compared to other shuttle run field tests, YYIET seems to be a weak indicator of aerobic power in youth moderately trained youth soccer player.

Adolescent↗

PubMed2006

Relationship between push phase and final race time in skeleton performance.

The aim of this study was to examine the relationship between push-time and final race time in skeleton participants during a series of major international competitions to determine the importance of the push phase in skeleton performance. Correlations were computed from the first and second heat split data measured during 24 men and 24 women skeleton competitions. Body mass, height, age, and years of experience of the first 30 men and women athletes of the skeleton, bobsleigh and luge 2003-2004 World Cup ranking were used for the comparison between sliding sports. Moderate but significant correlations (p < 0.05) were found between push-time and final race time in men (r(mean) = 0.48) and women (r(mean) = 0.63). No correlations were found between changes in the individual push-time between the first and second heat with the corresponding changes in final race time. The bobsleigh sliders are heavier than the athletes of the other sliding disciplines. Luge athletes have more experience and are younger than bobsleigh and skeleton sliders. The results of this study suggest that a fast push phase is a prerequisite to success in competition and confirms that the selection of skeleton athletes based on the ability to accelerate to a maximum speed quickly could be valid. However, a good or improved push-time does not ensure a placement in the top finishing positions. On the basis of these results, we suggest that strength and power training is necessary to maintain a short push-time but additional physical training aimed to enhance the push phase might not reflect performance improvements. The recruitment of younger athletes and an increase of youthful competitive activity may be another effective way to reach international competitive results.

Acceleration↗

PubMed2006

Aerobic fitness and yo-yo continuous and intermittent tests performances in soccer players: a correlation study.

Yo-yo tests are very popular in soccer; however, no study has addressed details of their relation to canonical aspects of aerobic fitness. Furthermore, no information is available on the effect of the individual levels of lower limbs' explosive strength on yo-yo tests in soccer players. The purpose of this study was to examine the physiological determinants of Yo-yo Endurance Test Level 2 (YYETL2) and Yo-yo Intermittent Recovery Test Level 1 (YYIRTL1) in soccer players. Twenty-four soccer players (body mass, 74.6 +/- 8.5 kg; height, 178.1 +/- 4.5 cm; age, 25.6 +/- 5.1 years) were tested for VO2max and ventilatory threshold (VT) on a motorized treadmill. Lower-limb explosive strength was assessed using vertical countermovement jumps (CMJ) performed on a force platform. Results showed that YYETL2 and YYIRTL1 performances (m) were significantly related (r = 0.75, p = 0.00002). YYETL2 results were significantly related to VO2max, VTVO2, and speed at VT (r = 0.75, 0.76, and 0.83, respectively; p < 0.00002). Peak treadmill speed results were significantly related to YYETL2 and YYIRTL1 (r = 0.87 and 0.71, respectively; p < 0.0003). YYIRTL1 was related to CMJ peak power (r = 0.57; p = 0.003). These findings show that YYETL2 and YYIRTL1, although adopting similar starting and progression speeds, are influenced by different physiological variables. From these results, YYETL2 can be considered an aerobic fitness-related field test, whereas YYIRTL1 can be regarded as an aerobic-anaerobic, soccer-specific field test.

Adult↗

PubMed2005

Physiological assessment of aerobic training in soccer.

Physiological assessment of soccer training usually refers to the measurement of anatomical, physiological, biochemical and functional changes specific to the sport discipline (training outcome). The quality, quantity and organization of physical exercises (training process) are, on the other hand, usually described by the external work imposed by the coach on his or her athletes. In this review, we demonstrate that this approach is not appropriate in soccer, as training is often based on group exercises. The physiological stress (internal load) induced by such training often differs between individuals. Here, we present some physiological laboratory-based tests and field tests used to evaluate training outcomes in soccer, together with methods based on heart rate and perceived exertion to quantify internal load imposed during training. The integrated physiological assessment of both training outcome and process allows researchers: (1) to improve interpretation of physical tests used to verify the effectiveness of training programmes; (2) to evaluate the organization of the training load in order to design periodization strategies; (3) to identify athletes who are poor responders; (4) to control the compliance of the training completed to that planned by the coach; and (5) to modify the training process before the assessment of its outcome, thus optimizing soccer performance.

Exercise↗

PubMed2005

Physiological correlates to off-road cycling performance.

The aim of this study was to examine the relationships between maximal and submaximal tests for aerobic fitness and performance in an off-road cross-country circuit race. Thirteen competitive off-road male cyclists participated in the study. Peak oxygen uptake (VO2peak), peak power output, and lactate thresholds corresponding to 1 mmol x l(-1) above baseline (lactate threshold) and to 4 mmol x l(-1) (onset of blood lactate accumulation) were measured during an incremental cycling test. Race time and final ranking within the same group of cyclists were determined during a cross-country off-road competition. All correlations between the measured parameters of aerobic fitness and off-road cycling performance were significant, particularly between race time and physiological parameters scaled to body mass0.79 (r = -0.68 to -0.94; P < 0.05) and between final ranking and physiological parameters expressed relative to body mass0.79 (r = -0.81 to - 0.96; P < 0.001). Moreover, there was a large difference (effect sizes = 1.12-1.70) in all measured parameters of aerobic fitness between the group of six cyclists with a race time above the median and the group of six cyclists with a race time below the median (P < 0.05). In conclusion, the results of this study provide empirical support to the widespread use of these maximal (VO2peak, peak power output) and submaximal (lactate thresholds) parameters of aerobic fitness in the physiological assessments of off-road cyclists. Furthermore, our results suggest body size should be taken into account when evaluating such athletes.

Adolescent↗

PubMed2004

Validity of heart rate as an indicator of aerobic demand during soccer activities in amateur soccer players.

In order to validate the use of heart rate (HR) in describing and monitoring physiological demands during soccer activities, the HR versus oxygen uptake ( V(.)O(2)) relationship determined on the field during soccer-specific exercises was compared to that found in the laboratory during treadmill exercise. Seven male amateur soccer players [mean (SE), age 25.3 (1.2) years, body mass 72.9 (2.1) kg, stature 1.76 (0.03) m] performed three trials on the field (two laps of a purpose-made circuit including a variety of soccer activities) at different intensities (moderate, high and very high, according to their rate of perceived exertion) and an incremental test on a treadmill in the laboratory. HR increased linearly with V(.)O(2) during both field and laboratory tests according to exercise intensity ( P<0.01). The mean correlation coefficients of the HR- V(.)O(2) relationships obtained in the laboratory and on the field were 0.984 (0.012) and 0.991 (0.005) ( P<0.001), respectively. The mean value of the HR- V(.)O(2) regression equation slope and intercept obtained in laboratory [0.030 (0.002) and 79.6 (4.6), respectively] were not significantly different compared to those found on the field [0.032 (0.003) and 76.7 (9.7)]. The present study seems to confirm that HR measured during soccer exercises effectively reflects the metabolic expenditure of this activity. Thus, with the aid of laboratory reference tests, the physiological demands of soccer activities can be correctly estimated from HR measured on the field in amateur soccer players.

Adult↗

PubMed2004

Use of RPE-based training load in soccer.

PURPOSE: The ability to accurately control and monitor internal training load is an important aspect of effective coaching. The aim of this study was to apply in soccer the RPE-based method proposed by Foster et al. to quantify internal training load (session-RPE) and to assess its correlations with various methods used to determine internal training load based on the HR response to exercise. METHODS: Nineteen young soccer players (mean +/- SD: age 17.6 +/- 0.7 yr, weight 70.2 +/- 4.7 kg, height 178.5 +/- 4.8 cm, body fat 7.5 +/- 2.2%, VO2max, 57.1 +/- 4.0 mL x kg x min) were involved in the study. All subjects performed an incremental treadmill test before and after the training period during which lactate threshold (1.5 mmol x L above baseline) and OBLA (4.0 mmol x L) were determined. The training loads completed during the seven training weeks were determined multiplying the session RPE (CR10-scale) by session duration in minutes. These session-RPE values were correlated with training load measures obtained from three different HR-based methods suggested by Edwards, Banister, and Lucia, respectively. RESULTS: Individual internal loads of 479 training sessions were collected. All individual correlations between various HR-based training load and session-RPE were statistically significant (from r = 0.50 to r = 0.85, P < 0.01). CONCLUSION: The results of this study show that the session-RPE can be considered a good indicator of global internal load of soccer training. This method does not require particular expensive equipment and can be very useful and practical for coaches and athletic trainer to monitor and control internal load, and to design periodization strategies.

Adolescent↗