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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Physiological and match performance characteristics of field hockey players

Leslie, Vikki January 2012 (has links)
This thesis aimed to examine the physiological and match performance characteristics of field hockey players in relation to age, sex and playing standard. The relationship between the physiological and match performance characteristics of players was also investigated. In Chapter 4, the physiological characteristics of 159 elite male international U16, U18, U21 and senior (mean±S.E. age, 15±0.1; 16.9±0.2; 20.1±0.2 and 24.9±0.7 years respectively) players were profiled. Seventy-seven players completed a series of lab tests including: treadmill VO2peak, repeated 10 x 6 s cycle ergometer sprints, maximum blood lactate concentration and running economy during submaximal treadmill running. Eighty-two players completed a 15 m sprint and a multi-stage fitness test. Field test characteristics of successful (went on to compete at senior international level) and unsuccessful (did not compete beyond junior international level) players were compared. Directly determined VO2peak was not different when squads were compared (U16 vs. U18 vs. U21 vs. senior; 58.7±0.9 vs. 60.5±0.8 vs. 60.9±0.9 vs. 59.7±0.9; ml.kg-1.min-1; P>0.05). Successful U21 players were faster over 15 m than unsuccessful U21 players (successful U21 vs. unsuccessful U21; 2.37±0.02 vs. 2.44±0.02; s; P<0.05). These findings suggest that a high peak oxygen uptake of approximately 60 ml.kg-1.min-1 is a prerequisite for elite male hockey players from at least U16 level onwards. Sprint speed may be a key factor determining progression from junior to senior international level. Chapter 5 examined the match performance characteristics of male U16 (16.0±0.3 years, n=8), U18 (17.8±0.1 years, n=14) and senior (25.7±0.6 years, n=16) elite level players. Players wore a non-differential GPS device (SPI Elite, GPSports, Australia) during at least one full match. Duration, distance covered, mean speed and maximum speed were obtained for the total match and the 1st and 2nd halves. Match activities were analysed in absolute terms and also relative to an individual's maximal speed. Results showed players from all age groups covered similar total distances (5385.0±315.7; 6608.4±317.9; 6260.4±296.2, m, U16 vs. U18. vs. senior, P>0.05) at similar mean speeds (8.0±0.2 vs. 8.1±0.3 vs. 7.6±0.1, km.h-1, U16 vs. U18. vs. senior, P>0.05) and the majority of the movements completed by players could be categorised as low-moderate intensity (<14.5 km.h-1) during match play (87.6 %, 86.7 % and 87.8 % for U16, U18 and senior players respectively). All age groups demonstrated fatigue during the second half of a match, but senior players exhibited the highest decrement in high intensity activity (>14.5 km.h-1). Results from this study suggest that the activities associated with elite level hockey competition are predominantly low intensity. Similar demands are placed on elite players from U16 to senior level. Age-related differences in exercise metabolism are likely to account for differences in the fatigue profiles of high intensity activity over the course of a game. Using the same methodology as Chapter 5, Chapter 6 sought to profile the match performance characteristics of elite female U16 (16.2±0.1 years, n=7), U18 (17.6±0.2 years, n=5) and senior (24.5±0.8 years, n=15) players. Amongst female players there were no differences between age groups in the distance covered (4962.3±295.1 vs. 5202.5±155.5 vs. 5581.1±208.8 m, U16 vs. U18 vs. senior, P>0.05) the mean speed (23.3±0.6 vs. 23.5±0.7 vs. 24.3±0.3 km.h-1, U16 vs. U18 vs. senior, P>0.05) during a match. While senior females completed more high intensity movement (>14.5 km.h-1) than U16 players (5.0±0.8 vs. 7.5±0.6 %, P<0.05), there were no other differences in the match activity profiles between age groups (analysed in absolute and relative terms). Senior females demonstrated a reduction in the amount of high intensity activity during the second half of a match. These results suggest that, similar to elite male hockey, elite female competition predominantly involves activity that can be classified as low-moderate intensity. The decrement in high intensity activity during the second half of a match in senior players may be related to performing significantly more high intensity bouts over the course of a game than younger players. In Chapter 7, the relationship between the physiological and performance characteristics of 26 university level female players (20.8±0.5 years) was examined. The distance travelled during games in terms of low (0-6 km.h-1), moderate (6-14.5 km.h-1) and high intensity (>14.5 km.h-1) movements was examined. Players also completed the Yo-Yo Intermittent Recovery Test level 1 (YYIRT), the Interval Shuttle Run Test (ISRT), the Multi-Stage Fitness Test (MSFT) and a laboratory assessment of speed at 4 mmol.L-1 blood lactate concentration and a VO2max test. The total distance covered during a match was associated with VO2max, speed at 4 mmol.L-1, YYIRT, ISRT and MSFT performance (Pearson's correlation coefficients; 0.58; 0.67; 0.67; 0.61; 0.58, respectively, P<0.05 in all cases). Mean speed was also related to VO2max, speed at 4 mmol.L-1, YYIRT, ISRT and MSFT (Pearson's correlation coefficients: 0.58; 0.71; 0.61; 0.62; 0.54 respectively, P<0.05 in all cases). The amount of high intensity activity, which may be an indicator of the quality of match performance was most closely associated with VO2max, YYIRT and ISRT (Pearson's correlation coefficients: 0.60; 0.60; 0.54 respectively, P<0.01 in all cases). These results suggest that player performance during a match is related to their physiological characteristics. Such characteristics can be examined using both field and laboratory tests. Chapter 8 examined the physiological, skill and match performance characteristics of three different competitive levels of female field hockey players. The players were recruited from the 1st (n=13), 2nd (n=10) and 3rd (n=16) teams of Loughborough University Ladies Hockey Club. Players completed field based physiological assessments (YYIRT, ISRT, MSFT and 5,10, 20 and 30 m sprints) and a field based hockey specific dribbling test. Laboratory measures included treadmill VO2max and a submaximal speed lactate test. Results from comparisons between teams did not indicate any differences based on any physiological or match performance parameters (P>0.05 in all cases). Superior dribbling skill, as assessed during a hockey-specific skill test, discriminated 1st team from 2nd and 3rd team players (2.58±0.22 vs. 4.43±0.28 and 3.90±0.27 s, P<0.01, 1st vs. 2nd and 1st vs. 3rd). These results suggest that skill is crucial to determining success in competitive field hockey. Based on the investigations outlined above it appears a relatively high maximal oxygen uptake is a prerequisite for elite level players from junior to senior levels, although it probably does not distinguish between playing standards. In contrast both short distance speed and skill would seem to discriminate between different standards of field hockey performance. Therefore, in order to succeed at the elite level of field hockey players must possess a certain degree of speed, aerobic power and hockey specific dribbling ability. In terms of match play, it would appear that the demands placed on elite junior and senior players during match play are very similar and this observation may explain why a relatively high aerobic power is required even at junior level. Match performance (in particular with respect to high intensity activities) may be different between elite and sub-elite players and because there appears to be a strong link between physiological and match performance characteristics, laboratory and field based assessments may be used to provide an indication of a player's likely physical performance during a match.
2

Mechanical and perceived behaviour of synthetic turf field hockey pitches

Young, Colin January 2006 (has links)
This research has investigated the behaviour of synthetic turf pitches for field hockey. A combination of mechanical and perceived data collection methods were used to provide an increased understanding of pitch behaviour. A methodology was developed to elicit perceptions from elite field hockey players. Part of the method was an inductive analysis of players responses during a participant led interview. This enabled the development of a 'structured relationship model' which Illustrated five general dimensions. Each general dimension was part of a hierarchical structure formed from base themes via players responses. Based on characteristics identified in the 'structured relationship model' a questionnaire was designed to quantify the Importance and preferences of certain playing characteristics for elite field hockey players. It was found that players thought 'surface consistency' and 'the ability to demonstrate deft skills' as the most Important surface characteristics it was also identified that given a choice the majority of players would like to play on a fast, low bouncing surface conducive to deft stickwork with 'high' underfoot grip, no ball spin and with a moderate hardness Monitoring during the construction of a world class water-based synthetic turf hockey pitch has shown the influence each layer on the overall pitch system. Novel equipment to the sports Industry was used to evaluate each layer during construction and a large amount of variability was identified across the pitch. it was identified that if the subgrade had a weak area of low stiffness then the subsequent layers above were also vulnerable to low measurements. This highlighted the Importance of quality control during construction A laboratory investigation using a combination of shockpad and carpet samples identified the Influence different systems had on the playing surface. During the investigation testing was conducted on the laboratory floor and in a prepared box constructed to Simulate a 'typical' pitch. it was identified that the layers below the shockpad had little Influence on the measurements. Conditions were monitored and it was identified the Importance water has on the behaviour of the surface lt was found to significantly reduce ball rebound height and rotational traction A series of site investigations using mechanical tests has shown the variability between pitches even at elite standard Six pitches were evaluated and a range of results were obtained and compared with the requirements from the international governing body for field hockey. A correlation between the artificial athlete Berlin and 2.25 kg Clegg impact hammer demonstrated that the Clegg hammer could be a valuable tool for surface assessment. A comparison of players perceptions and the mechanical measurements of six pitches were evaluated. lt was found that the perceived behaviour of ball rebound, underfoot traction and surface hardness correlated well with measured data. However, it was shown that players perceptions of surface pace did not correspond to measurements of ball roll distance. The three main sections of work comprising site data collection, laboratory testing and elicitation of players perceptions have been used together to provide a much greater understanding of the behaviour of synthetic turf pitches for field hockey.

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