2,656 research outputs found
Design and development of a solar array drive
The design and development of a dry lubricated direct drive solar array pointing mechanism is discussed for use on the Orbital Test Satellite (OTS), MAROTS, European Communication Satellite (ECS), and others. Results of life testing the original prototype and the OTS mechanism are presented together with an appraisal of expected future development
The spatiotemporal characteristics of 0–24-Goal Polo
Global positioning systems (GPS) have recently been shown to reliably quantify the spatiotemporal characteristics of Polo, with the physiological demands of Polo play at low- and high-goal levels also investigated. This study aims to describe the spatiotemporal demands of Polo across 0–24 goal levels. A player-worn GPS unit was used to quantify distance, speed and high-intensity activities performed. Data were divided into chukkas and five equine-based speed zones, grouped per cumulative player handicap and assessed using standardized mean differences. Average distance and speed per chukka increased in accordance with cumulative player handicap, with the magnitude of differences being trivial–large and trivial–very large, respectively. Differences between time spent in high-intensity speed zones (zones 4 and 5) show a linear increase in magnitude, when comparing 0 goal Polo to all other levels of play (Small–Very Large; 6–24 goals, respectively). High-intensity activities predominantly shared this trend, displaying trivial–large differences between levels. These findings highlight increased cardiovascular, anaerobic and speed based physiological demands on Polo ponies as playing level increases. Strategies such as high-intensity interval training, maximal speed work and aerobic conditioning may be warranted to facilitate this development and improve pony welfare and performance
Distance, speed and high-intensity characteristics of 0 to 24-goal, mixed and women’s polo
This dataset presents information pertaining to the spatiotemporal characteristics of Polo play from a 0 to 24-goal level. Data were collected by player worn GPS units, across a New Zealand Polo season. The dataset comprises observations from 466 chukkas of Polo, across mixed and women’s only Polo and is curated by cumulative player handicap. Data are presented for distance, speed and high intensity metrics, which have further ategorised into five equine-based speed zones. The purpose of this dataset is to provide a detailed quantification of a range of Polo performance levels, advancing the scope and size of previous Polo literature that has employed GPS technology. This dataset may be of value to equine scientists and trainers, veterinary practitioners and sports scientists
The spatiotemporal characteristics of 0–24-goal polo
Global positioning systems (GPS) have recently been shown to reliably quantify the spatiotemporal characteristics of Polo, with the physiological demands of Polo play at low- and high-goal levels also investigated. This study aims to describe the spatiotemporal demands of Polo across 0–24 goal levels. A player-worn GPS unit was used to quantify distance, speed and high-intensity activities performed. Data were divided into chukkas and five equine-based speed zones, grouped per cumulative player handicap and assessed using standardized mean differences. Average distance and speed per chukka increased in accordance with cumulative player handicap, with the magnitude of differences being trivial–large and trivial–very large, respectively. Differences between time spent in high-intensity speed zones (zones 4 and 5) show a linear increase in magnitude, when comparing 0 goal Polo to all other levels of play (Small–Very Large; 6–24 goals, respectively). High-intensity activities predominantly shared this trend, displaying trivial–large differences between levels. These findings highlight increased cardiovascular, anaerobic and speed based physiological demands on Polo ponies as playing level increases. Strategies such as high-intensity interval training, maximal speed work and aerobic conditioning may be warranted to facilitate this development and improve pony welfare and performance
All things being equal: Spatiotemporal differences between open and women’s 16-goal polo
Polo is an equestrian team sport, consisting of Open and Women’s only handicapping systems. As cumulative player handicap increases in Open Polo, distance covered, average speeds and high intensity work performed per chukka also increase. These activities may differ in terms of distribution of, and their affect upon, match outcome in Women’s Polo, and thus have implications for equine preparation and management. This study aimed to quantify spatiotemporal differences between Open and Women’s Polo when matched for handicap and assess their affect upon chukka and match outcome using a prospective cohort design. Distance, speed and high intensity activity data were collected via player worn global positioning system (GPS) units during 16-goal Open and Women’s Polo tournaments. Notational analysis quantified chukka duration and chukka and game outcomes. Between group differences were assessed by independent samples t-tests, and two factor mixed effects ANOVA for within group analyses. Between group differences were analysed using an independent samples t-test with alpha defined a priori as p<0.05. Open and Women’s Polo differed by a small to large extent (ES: 0.54 – 1.81) for all spatiotemporal metrics. In Open Polo, players covered moderately more distance (429.0m; 238.9m to 619.0m), with small to large increases in high intensity activities performed in games won. Whereas in Women’s Polo, moderately higher maximum speeds were attained in games won (17.13 km/h; 11.86 km/h to 22.40 km/h) and a small increase in accelerations performed (5.1; 0.2 to 10.0). Open and Women’s Polo, when matched for handicap, present with small to large spatiotemporal differences that are likely of practical significance, and influence game outcome differently between codes. These differences do not necessarily mean that Polo ponies need to be trained differently for each code
Distance, speed and high intensity characteristics of 0 to 24-goal, mixed and women’s polo
This dataset presents information pertaining to the spatiotemporal characteristics of Polo play from a 0 to 24-goal level. Data were collected by player worn GPS units, across a New Zealand Polo season. The dataset comprises observations from 466 chukkas of Polo, across mixed and women’s only Polo and is curated by cumulative player handicap. Data are presented for distance, speed and high intensity metrics, which have further categorised into five equine-based speed zones. The purpose of this dataset is to provide a detailed quantification of a range of Polo performance levels, advancing the scope and size of previous Polo literature that has employed GPS technology. This dataset may be of value to equine scientists and trainers, veterinary practitioners and sports scientists
The spatiotemporal characteristics of 0–24-goal polo
Polo is an equestrian sport that requires two teams of four players to score goals at opposing ends of a 150 m × 275 m pitch. Each player is rated on a handicap system (−2 to +10) that quantifies their abilities and permits their inclusion in different levels of Polo play; the cumulative handicap of the four players sets the level of play. Using GPS technology, we investigated how levels of Polo differ regarding distance covered, speeds achieved and high-intensity activities performed. As cumulative Polo handicap increased, so too did the distances and average speeds attained, decelerations performed and impacts encountered during each period of play. These findings suggest that as each player improves and increases their handicap, they will need to ensure the ponies they play have sufficient aerobic, anaerobic and speed capacities to perform effectively at that level. This information provides valuable insights to Polo players, grooms and equine vets, as to how they can best prepare their ponies for game-day and how they may be able to maintain pony longevity in the sport
Strength and reaction time capabilities of New Zealand polo players and their association with polo playing handicap
Polo is an equestrian team sport consisting of four players per team, with level of play determined by cumulative player handicap (-2 to + 10 goals), with a higher handicap denoting a better player. There is minimal literature investigating Polo players’ physical attributes, hence the understanding of the physical characteristics that may contribute to an improved handicap are unknown. This study sought to identify the relationship between pertinent strength measures (left and right hand grip strength; absolute and relative isometric mid-thigh pull) and reaction time in Polo handicap in 19 New Zealand Polo players, and ascertain whether handicap could be predicted by these measures. Correlation coefficients were expressed using R values, accompanying descriptors and 90% confidence intervals (C.I.). Variance explained was expressed via the R2 statistic, and statistical significance set at p < 0.05. Right hand grip strength, isometric mid-thigh pull values were found to significantly correlate to and explain variance within Polo player handicap (all moderate to large correlations; p< 0.05). Whereas left hand grip strength (R: 0.380; 90% C.I. -0.011 to 0.670) and reaction time (0.020; -0.372 to 0.406) were non-significant, moderate and trivial correlates and predictors of handicap respectively. Practically, these findings highlight the differing roles between rein and mallet hands of Polo players and emphasise the importance of a strong and stable platform when riding and striking the ball. Lack of association with reaction time may be explained in part by higher handicapped Polo players employing a more proactive approach to the game
The spatiotemporal characteristics of 0 – 24 goal polo
Global positioning systems (GPS) have recently been shown to reliably quantify the spatiotemporal characteristics of Polo, with the physiological demands of Polo play at low and high goal levels also investigated. This study aimed to describe the spatiotemporal demands of Polo across 0 – 24 goal levels. A player worn GPS unit was used to quantify distance, speed and high intensity activities performed. Data was divided into chukkas and five equine-based speed zones, grouped per cumulative player handicap and assessed using standardised mean differences. Average distance and speed per chukka increased in accordance with cumulative player handicap, with the magnitude of differences being Trivial – Large and Trivial – Very Large, respectively. Differences between time spent in speed zones 4 and 5 show a linear increase in magnitude, when comparing 0 goal Polo to all other levels of play (Small – Very Large; 6 – 24 goals, respectively). High intensity activities predominantly shared this trend, displaying Trivial – Large differences between levels. These findings highlight the increasingly demanding cardiovascular, anaerobic and speed-based needs of Polo ponies as playing level increases. Strategies such as high intensity interval training, maximal speed work and aerobic conditioning may be warranted to facilitate this development and improve pony welfare and performance
Performance characteristics of a winning polo team
Polo is played globally, and is contested by two teams of four players on horseback. Despite popularity, there is little academic literature assessing Polo players, and what constitutes successful Polo performance. One reason for this may be Polo’s unique player rating system, the handicap, which quantifies individuals and teams’ level of play. We sought to characterise the play of a tournament winning high-goal polo team (KPF) using percent and raw differences between teams using a customised matrix, which was designed with input from international polo players. Secondly, we assessed the association between player handicap and success rates of key performance metrics. KPF won five of seven games played, with forehand middle (FHM) being the least variable shot (-4 to 5% success rate), whereas long backhand shots were the most variable (-50 to 45% success rate). Fewer turnovers were conceded than the opposition in all games won, and in four out of the five winning games, more penalties were awarded to KPF than their opponents. At an individual level, FHM was significantly correlated to player handicap (0.562, Large: p<0.05). Player handicap was also moderately correlated with backhand middle (0.33), backhand long (0.361), and ride off (0.362) success rates. Turnovers and penalties awarded confer clear attacking and goal-scoring opportunities. FHM, backhand shots and ability to contest for the ball (ride off) are key performance metrics, positively associated with player handicap, and higher handicap players demonstrate greater success rates and or less variability than those with lower handicaps. However, variability within players of the same handicap is evident, suggesting subjectivity of the handicapping system
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