Search Results

You are looking at 71 - 80 of 278 items for :

  • "global positioning systems" x
Clear All
Restricted access

Darren Burgess, Geraldine Naughton and Kevin Norton

Purpose:

The understanding of the gap between Under 18 y (U18) and senior-level competition and the evolution of this gap in Australian Football lack a strong evidence base. Despite the multimillion dollars invested in recruitment, scientific research on successful transition is limited. No studies have compared individual players’ movement rate, game statistics and ball speed in U18 and senior competition of the Australian Football League across time. This project compared differences in player movement and ball speed between matches from senior AFL competitive matches and U18 players in the 2003 and 2009 seasons.

Methods:

TrakPerformance Software and Global Positioning System (GPS) technology were used to analyze the movement of players, ball speed and game statistics. ANOVA compared the two levels of competition over time.

Results:

Observed interactions for distance traveled per minute of play (P = .009), number of sprints per minute of play (P < .001), time spent at sprint speed in the game (P < .001), time on field (P < .001), and ball speed (P < .001) were found. Subsequent analysis identified increases in movement patterns in senior AFL competition in 2009 compared with the same level of competition in 2003 and U18 players in 2003 and 2009.

Conclusions:

Senior AFL players in 2009 were moving further, sprinting relatively more frequently, playing less time and playing at game speeds significantly greater than the same senior competition in 2003 as well as compared with both cohorts of U18 players.

Restricted access

Matthew C. Varley, George P. Elias and Robert J. Aughey

Purpose:

To compare the peak 5-min period of high-velocity running (HiVR) during a soccer match using a predefined vs a rolling time interval.

Methods:

Player movement data were collected from 19 elite Australian soccer players over 11 competitive matches (77 individual match files) using a 5-Hz global-positioning system. Raw velocity data were analyzed to determine the period containing the greatest HiVR distance per match half and the distance covered in the subsequent epoch. Intervals were identified using either a predefined (distance covered in 5 min at every 5-min time point) or rolling (distance covered in 5 min from every time point) method. The percentage difference ± 90% confidence limits were used to determine differences between methods.

Results:

Predefined periods underestimated peak distance covered by up to 25% and overestimated the subsequent epoch by up to 31% compared with rolling periods. When the distance decrement between the peak and following period was determined, there was up to a 52% greater reduction in running performance using rolling periods than predefined ones.

Conclusions:

It is recommended that researchers use rolling as opposed to predefined periods when determining specific match intervals because they provide a more accurate representation of the HiVR distance covered. This will avoid underestimation of both match running distance and the decrement in running performance after an intense period of play. This may have practical implications for not only researchers but also staff involved in a club setting who use this reduction as evidence of transient fatigue during a match.

Restricted access

Alex Ross, Nicholas D. Gill and John B. Cronin

Purpose:

To compare the running demands and match activity profiles of international and provincial rugby sevens players.

Participants:

84 rugby sevens players, consisting of 16 international players from 1 team and 68 provincial players from 8 teams.

Methods:

Global positioning system analysis was completed during international and provincial tournament matches. Video analysis was also used to quantify the individual match activities during tournament matches.

Results:

Trivial to moderate differences were found in the running demands of international and provincial players, with internationals covering a greater distance at very high speed (ES = 0.30) and performing a greater number of sprints (ES = 0.80). Small differences were found between the 2 levels in all but total tackles (ES = 0.07) and defensive ruck effectiveness (ES = 0.64). International matches incurred a greater overall ball-in-play time than provincial matches (proportion ratio = 1.32).

Conclusions:

These findings demonstrate that both physical and technical factors distinguish international and provincial rugby sevens, although overall match demands are similar.

Restricted access

Louise Martin, Anneliese Lambeth-Mansell, Liane Beretta-Azevedo, Lucy A. Holmes, Rachel Wright and Alan St Clair Gibson

Purpose:

Given the paucity of research on pacing strategies during competitive events, this study examined changes in dynamic high-resolution performance parameters to analyze pacing profiles during a multiple-lap mountain-bike race over variable terrain.

Methods:

A global-positioning-system (GPS) unit (Garmin, Edge 305, USA) recorded velocity (m/s), distance (m), elevation (m), and heart rate at 1 Hz from 6 mountain-bike riders (mean ± SD age = 27.2 ± 5.0 y, stature = 176.8 ± 8.1 cm, mass = 76.3 ± 11.7 kg, VO2max = 55.1 ± 6.0 mL · kg−1 . min−1) competing in a multilap race. Lap-by-lap (interlap) pacing was analyzed using a 1-way ANOVA for mean time and mean velocity. Velocity data were averaged every 100 m and plotted against race distance and elevation to observe the presence of intralap variation.

Results:

There was no significant difference in lap times (P = .99) or lap velocity (P = .65) across the 5 laps. Within each lap, a high degree of oscillation in velocity was observed, which broadly reflected changes in terrain, but high-resolution data demonstrated additional nonmonotonic variation not related to terrain.

Conclusion:

Participants adopted an even pace strategy across the 5 laps despite rapid adjustments in velocity during each lap. While topographical and technical variations of the course accounted for some of the variability in velocity, the additional rapid adjustments in velocity may be associated with dynamic regulation of self-paced exercise.

Restricted access

Daniel A. Rodriguez, Gi-Hyoug Cho, John P. Elder, Terry L. Conway, Kelly R. Evenson, Bonnie Ghosh-Dastidar, Elizabeth Shay, Deborah Cohen, Sara Veblen-Mortenson, Julie Pickrell and Leslie Lytle

Background:

Studies that have combined accelerometers and global positioning systems (GPS) to identify walking have done so in carefully controlled conditions. This study tested algorithms for identifying walking trips from accelerometer and GPS data in free-living conditions. The study also assessed the accuracy of the locations where walking occurred compared with what participants reported in a diary.

Methods:

A convenience sample of high school females was recruited (N = 42) in 2007. Participants wore a GPS unit and an accelerometer, and recorded their out-of-school travel for 6 days. Split-sample validation was used to examine agreement in the daily and total number of walking trips with Kappa statistics and count regression models, while agreement in locations visited by walking was examined with geographic information systems.

Results:

Agreement varied based on the parameters of the algorithm, with algorithms exhibiting moderate to substantial agreement with self-reported daily (Kappa = 0.33−0.48) and weekly (Kappa = 0.41−0.64) walking trips. Comparison of reported locations reached by walking and GPS data suggest that reported locations are accurate.

Conclusions:

The use of GPS and accelerometers is promising for assessing the number of walking trips and the walking locations of adolescent females.

Restricted access

Philip R. Hayes, Kjell van Paridon, Duncan N. French, Kevin Thomas and Dan A. Gordon

Purpose:

The aim of this study was to develop a laboratory-based treadmill simulation of the on-course physiological demands of an 18-hole round of golf and to identify the underlying physiological responses.

Methods:

Eight amateur golfers completed a round of golf during which heart rate (HR), steps taken, and global positioning system (GPS) data were assessed. The GPS data were used to create a simulated discontinuous round on a treadmill. Steps taken and HR were recorded during the simulated round.

Results:

During the on-course round, players covered a mean (±SD) of 8,251 ± 450 m, taking 12,766 ± 1,530 steps. The mean exercise intensity during the on-course round was 31.4 ± 9.3% of age-predicted heart rate reserve (%HRR) or 55.6 ± 4.4% of age-predicted maximum HR (%HRmax). There were no significant differences between the simulated round and the on-course round for %HRR (P = .537) or %HR max (P = .561) over the entire round or for each individual hole. Furthermore, there were no significant differences between the two rounds for steps taken. Typical error values for steps taken, HR, %HRmax, and %HRR were 1,083 steps, ±7.6 b·min-1, ±4.5%, and ±8.1%, respectively.

Conclusion:

Overall, the simulated round of golf successfully recreated the demands of an on-course round. This simulated round could be used as a research tool to assess the extent of fatigue during a round of golf or the impact of various interventions on golfers.

Restricted access

Andrew D. White and Niall MacFarlane

Purpose:

The current study assessed the impact of full-game (FG) and time-on-pitch (TOP) procedures for global-positioning-system (GPS) analysis on the commonly used markers of physical performance in elite field hockey.

Methods:

Sixteen international male field hockey players, age 19–30, were studied (yielding 73 player analyses over 8 games). Physical activity was recorded using a 5-Hz GPS.

Results:

Distance covered, player load, maximum velocity, high-acceleration efforts, and distance covered at specified speed zones were all agreeable for both analysis procedures (P > .05). However, percentage time spent in 0–6 km/h was higher for FG (ES: –21% to –16%; P < .001), whereas the percentage time in all other speed zones (1.67–3.06 m/s, 3.06–4.17 m/s, 4.17–5.28 m/s, and > 6.39 m/s) and relative distance (m/min) were higher for TOP (ES: 8–10%, 2–7%, 2–3%, 1–1%, 0–1%, respectively; P < .001).

Conclusions:

These data demonstrate that GPS analysis procedures should be appropriate for the nature of the sport being studied. In field hockey, TOP and FG analysis procedures are comparable for distance-related variables but significantly different for time-dependent factors. Using inappropriate analysis procedures can alter the perceived physiological demand of elite field hockey because of “rolling” substitutions. Inaccurate perception of physiological demand could negatively influence training prescription (for both intensity and volume).

Restricted access

Pradeep Y. Ramulu, Emilie S. Chan, Tara L. Loyd, Luigi Ferrucci and David S. Friedman

Background:

Measuring physical at home and away from home is essential for assessing health and well-being, and could help design interventions to increase physical activity. Here, we describe how physical activity at home and away from home can be quantified by combining information from cellular network–based tracking devices and accelerometers.

Methods:

Thirty-five working adults wore a cellular network–based tracking device and an accelerometer for 6 consecutive days and logged their travel away from home. Performance of the tracking device was determined using the travel log for reference. Tracking device and accelerometer data were merged to compare physical activity at home and away from home.

Results:

The tracking device detected 98.6% of all away-from-home excursions, accurately measured time away from home and demonstrated few prolonged signal drop-out periods. Most physical activity took place away from home on weekdays, but not on weekends. Subjects were more physically active per unit of time while away from home, particularly on weekends.

Conclusions:

Cellular network–based tracking devices represent an alternative to global positioning systems for tracking location, and provide information easily integrated with accelerometers to determine where physical activity takes place. Promoting greater time spent away from home may increase physical activity.

Restricted access

Melody Oliver, Hannah Badland, Suzanne Mavoa, Mitch J. Duncan and Scott Duncan

Background:

Global positioning systems (GPS), geographic information systems (GIS), and accelerometers are powerful tools to explain activity within a built environment, yet little integration of these tools has taken place. This study aimed to assess the feasibility of combining GPS, GIS, and accelerometry to understand transport-related physical activity (TPA) in adults.

Methods:

Forty adults wore an accelerometer and portable GPS unit over 7 consecutive days and completed a demographics questionnaire and 7-day travel log. Accelerometer and GPS data were extracted for commutes to/from workplace and integrated into a GIS database. GIS maps were generated to visually explore physical activity intensity, GPS speeds and routes traveled.

Results:

GPS, accelerometer, and survey data were collected for 37 participants. Loss of GPS data was substantial due to a range of methodological issues, such as low battery life, signal drop out, and participant noncompliance. Nonetheless, greater travel distances and significantly higher speeds were observed for motorized trips when compared with TPA.

Conclusions:

Pragmatic issues of using GPS monitoring to understand TPA behaviors and methodological recommendations for future research were identified. Although methodologically challenging, the combination of GPS monitoring, accelerometry and GIS technologies holds promise for understanding TPA within the built environment.

Restricted access

Daniel Tan, Brian Dawson and Peter Peeling

Purpose:

This study aimed to quantify the hemolytic responses of elite female football (soccer) players during a typical weekly training session.

Methods:

Ten elite female football players (7 field players [FPs] and 3 goalkeepers [GKs]) were recruited from the Australian National Women’s Premier League and asked to provide a venous blood sample 30 min before and at the immediate conclusion of a typical weekly training session. During this training session, the players’ movement patterns were monitored via a 5-Hz global positioning system. The blood samples collected during the training session were analyzed for iron status via serum ferritin (SF) analysis, and the hemolytic response to training, via serum free hemoglobin (Hb) and haptoglobin (Hp) measurement.

Results:

50% of the participants screened were found to have a compromised iron stores (SF <35 μg/L). Furthermore, the posttraining serum free Hb levels were significantly elevated (P = .011), and the serum Hp levels were significantly decreased (P = .005), with no significant differences recorded between the FPs and GKs. However, the overall distance covered and the movement speed were significantly greater in the FPs.

Conclusions:

The increases in free Hb and decreases in Hp levels provide evidence that a typical team-sport training session may result in significant hemolysis. This hemolysis may primarily be a result of running-based movements in FPs and/or the plyometric movements in GKs, such as diving and tackling.