Physiological and match performance characteristics of field hockey players

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.