The reliability and accuracy of Polar Team Pro GPS units

2020 ◽  
pp. 175433712097666
Author(s):  
Zeki Akyildiz ◽  
Mehmet Yildiz ◽  
Filipe Manuel Clemente
Keyword(s):  
Body Mass ◽  
High Speed ◽  
Team Sport ◽  
Soccer Players ◽  
Reference Standard ◽  
Low Speed ◽  
Total Distance ◽  
Typical Error ◽  
Very High ◽  
Error Of Measurement

This study aimed to investigate the accuracy and reliability of Polar Team Pro GPS units (10 Hz) when used to measure distance and total distance covered in different speed zones. Eight amateur soccer players (age: 21.37 ± 1.40 years, height: 176.75 ± 5 cm, body mass: 176.75 ± 9.47 kg) completed a team sport simulation cycle. Two Polar Team Pro GPS units were positioned on each player’s chest, and one GPSports GPS unit (15 Hz) was positioned between the scapulae. The data obtained from the two Polar Team Pro GPS units were compared to determine inter-unit reliability. The data obtained from one of the Polar Team Pro GPS units and the GPSports GPS unit (reference standard) were compared to determine concurrent accuracy. There was acceptable inter-unit reliability of Polar Team Pro GPS units for total distance (TD), low speed running (LSR) (0.00–13.99 km h−1), high speed running (HSR) (14.00–19.99 km h−1) and very high speed running (VHSR) (>20.0 km h−1) with high ICCs (0.63, 0.99, 0.99 and 0.99, respectively), and low typical error of measurement (%) (TEM%) (4.64, 5.05, 1.06 and 2.89, respectively). Regarding accuracy, the ICCs were extremely high for LSR and HSR (0.99 and 0.92, respectively), but high for TD and VHSR (0.63 and 0.65, respectively). Moreover, TEM (%) values were very low for TD and LSR (0.6 and 1.6, respectively), but they were high for HSR and VHSR (13.8 and 13.1, respectively). Consequently, acceptable inter-unit reliability was observed, indicating that the Polar Team Pro GPS unit is suitable for tracking pertinent team-sport variables. Moreover, the Polar Team Pro GPS units (10 Hz) are accurate under the same conditions. However, the research showed that the two systems cannot be used interchangeably for quantifying distances covered at higher speeds.

Workload Monitoring in Top-level Soccer Players During Congested Fixture Periods

2020 ◽  
Vol 41 (10) ◽  
pp. 677-681 ◽  
Author(s):  
Antonio Gualtieri ◽  
Ermanno Rampinini ◽  
Roberto Sassi ◽  
Marco Beato
Keyword(s):  
Exposure Time ◽  
High Speed ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Soccer Players ◽  
Maximum Peak ◽  
Total Distance ◽  
Soccer Team ◽  
Peak Speed ◽  
Very High

AbstractThis study assessed the internal and external workload of starters and non-starters in a professional top-level soccer team during a congested fixture period. Twenty Serie A soccer players were monitored in this study during two mesocycles of 21 days each. Starters and non-starters were divided based on the match time played in each mesocycle. The following metrics were recorded: exposure time, total distance, relative total distance, high-speed running distance over 20 km·h−1, very high-speed running distance over 25 km·h−1, individual very high-speed distance over 80% of maximum peak speed, and rating of perceived exertion. Differences between starters and non-starters were found for: exposure time (effect size=large to very large), rating of perceived exertion (large to very large), total distance (large to very large), and individual very high-speed distance over 80% of maximum peak speed (moderate to large). Furthermore, differences for relative total distance, high-speed running distance over 20 km·h−1 and very high-speed running distance over 25 km·h−1 were small to moderate, but not significant. This study reports that during congested fixture periods, starters had higher exposure time, rating of perceived exertion, total distance, and individual very high-speed distance over 80% of maximum peak speed than non-starters.

Reliability of the 30-15 Intermittent Fitness Test in Semiprofessional Soccer Players

2016 ◽  
Vol 11 (2) ◽  
pp. 172-175 ◽  
Author(s):  
Christopher Thomas ◽  
Thomas Dos’Santos ◽  
Paul A. Jones ◽  
Paul Comfort
Keyword(s):  
Intraclass Correlation ◽  
Team Sport ◽  
Soccer Players ◽  
True Score ◽  
Good Reliability ◽  
Fitness Test ◽  
Typical Error ◽  
Reliable Assessment ◽  
Significant Difference ◽  
Error Of Measurement

Purpose:The purpose of this investigation was to determine the reliability of the 30-15 Intermittent Fitness Test (30-15IFT) in semiprofessional soccer players.Methods:Fourteen male semiprofessional soccer players performed the 30-15IFT on 2 occasions separated by 7 d. Reliability was assessed by intraclass correlation coefficient (ICC), typical error of measurement expressed as a coefficient of variation (CV), and smallest worthwhile change (SWC) to determine any significant difference between testing sessions.Results:Maximal intermittent running velocity (VIFT) demonstrated good reliability (ICC = .80) for between-sessions reliability. The CV was 2.5% for between-sessions reliability of the 30-15IFT. As the SWC (0.70 km/h) falls within the range in which the individual’s true score is likely to lie (1.0 km/h), the usefulness of the VIFT was rated as marginal. Despite the usefulness of the 30-15IFT being deemed marginal, a change in performance as small as 1.0 km/h (2 stages) in VIFT could be considered substantial or real.Conclusion:This study demonstrates that VIFT in the 30-15IFT is reliable, resulting in a reliable assessment of team-sport-specific cardiorespiratory fitness, with changes as small as 1.0 km/h (2 stages) in VIFT considered meaningful.

Do elite soccer players cover longer distance when losing? Differences between attackers and defenders

2020 ◽  
pp. 174795412098227
Author(s):  
Carlos Lago-Peñas ◽  
Anton Kalén ◽  
Miguel Lorenzo-Martinez ◽  
Roberto López-Del Campo ◽  
Ricardo Resta ◽  
...  
Keyword(s):  
New York ◽  
High Speed ◽  
Large Scale ◽  
Tracking System ◽  
Soccer Players ◽  
Running Performance ◽  
Situational Variables ◽  
Total Distance ◽  
Professional Soccer ◽  
Score Line

This study aimed to evaluate the effects playing position, match location (home or away), quality of opposition (strong or weak), effective playing time (total time minus stoppages), and score-line on physical match performance in professional soccer players using a large-scale analysis. A total of 10,739 individual match observations of outfield players competing in the Spanish La Liga during the 2018–2019 season were recorded using a computerized tracking system (TRACAB, Chyronhego, New York, USA). The players were classified into five positions (central defenders, players = 94; external defenders, players = 82; central midfielders, players = 101; external midfielders, players = 72; and forwards, players = 67) and the following match running performance categories were considered: total distance covered, low-speed running (LSR) distance (0–14 km · h−1), medium-speed running (MSR) distance (14–21 km · h−1), high-speed running (HSR) distance (>21 km · h−1), very HSR (VHSR) distance (21–24 km · h−1), sprint distance (>24 km · h−1) Overall, match running performance was highly dependent on situational variables, especially the score-line condition (winning, drawing, losing). Moreover, the score-line affected players running performance differently depending on their playing position. Losing status increased the total distance and the distance covered at MSR, HSR, VHSR and Sprint by defenders, while attacking players showed the opposite trend. These findings may help coaches and managers to better understand the effects of situational variables on physical performance in La Liga and could be used to develop a model for predicting the physical activity profile in competition.

A New Approach for Training-load Quantification in Elite-level Soccer: Contextual Factors

2020 ◽  
Author(s):  
Berni Guerrero-Calderón ◽  
Maximilian Klemp ◽  
Alfonso Castillo-Rodriguez ◽  
José Alfonso Morcillo ◽  
Daniel Memmert
Keyword(s):  
High Speed ◽  
Prediction Models ◽  
Contextual Factors ◽  
Soccer Players ◽  
Total Distance ◽  
Professional Soccer ◽  
Equivalent Distance ◽  
Physical Responses ◽  
Match Location

AbstractThe aims of this study were to analyse the physical responses of professional soccer players during training considering the contextual factors of match location, season period, and quality of the opposition; and to establish prediction models of physical responses during training sessions. Training data was obtained from 30 professional soccer players from Spanish La Liga using global positioning technology (N=1365 performances). A decreased workload was showed during training weeks prior to home matches, showing large effects in power events, equivalent distance, total distance, walk distance and low-speed running distance. Also, the quality of the opposition also affected the training workload (p<0.05). All regression-models showed moderate effects, with an adjusted R2 of 0.37 for metabolic-work, 0.34 for total distance covered, 0.25 for high-speed running distance (18–21 km·h−1), 0.29 for very high-speed running distance (21–24 km·h−1), 0.22 for sprint running distance (>24 km·h−1) and 0.34 for equivalent distance. The main finding of this study was the great association of match location, season period and quality of opposition on the workload performed by players in the training week before the match; and the development of workload prediction-models considering these contextual factors, thus proposing a new and innovative approach to quantify the workload in soccer.

Individual Response to External Training Load in Elite Football Players

2020 ◽  
Vol 15 (5) ◽  
pp. 696-704
Author(s):  
Håvard Wiig ◽  
Thor Einar Andersen ◽  
Live S. Luteberget ◽  
Matt Spencer
Keyword(s):  
External Load ◽  
High Speed ◽  
Training Load ◽  
Effect Sizes ◽  
Football Players ◽  
Individual Response ◽  
Total Distance ◽  
External Training ◽  
Tracking Devices ◽  
Very High

Purpose: To investigate within-player effect, between-player effect, and individual response of external training load from player tracking devices on session rating of perceived exertion training load (sRPE-TL) in elite football players. Methods: The authors collected sRPE-TL from 18 outfield players in 21 training sessions. Total distance, high-speed running distance (>14.4 m/s), very high-speed running distance (>19.8 m/s), PlayerLoad™, PlayerLoad2D™, and high-intensity events (HIE > 1.5, HIE > 2.5, and HIE > 3.5 m/s) were extracted from the tracking devices. The authors modeled within-player and between-player effects of single external load variables on sRPE-TL, and multiple levels of variability, using a linear mixed model. The effect of 2 SDs of external load on sRPE-TL was evaluated with magnitude-based inferences. Results: Total distance, PlayerLoad™, PlayerLoad2D™, and HIE > 1.5 had most likely substantial within-player effects on sRPE-TL (100%–106%, very large effect sizes). Moreover, the authors observed likely substantial between-player effects (12%–19%, small to moderate effect sizes) from the majority of the external load variables and likely to very likely substantial individual responses of PlayerLoad™, high-speed running distance, very high-speed running distance, and HIE > 1.5 (19%–30% coefficient of variation, moderate to large effect sizes). Finally, sRPE-TL showed large to very large between-session variability with all external load variables. Conclusions: External load variables with low intensity-thresholds had the strongest relationship with sRPE-TL. Furthermore, the between-player effect of external load and the individual response to external load advocate for monitoring sRPE-TL in addition to external load. Finally, the large between-session variability in sRPE-TL demonstrates that substantial amounts of sRPE-TL in training sessions are not explained by single external load variables.

scholarly journals Analysis of the Association between Running Performance and Game Performance Indicators in Professional Soccer Players

2019 ◽  
Vol 16 (20) ◽  
pp. 4032 ◽  
Author(s):  
Modric ◽  
Versic ◽  
Sekulic ◽  
Liposek
Keyword(s):  
Performance Indicators ◽  
High Intensity ◽  
High Speed ◽  
Body Height ◽  
Soccer Players ◽  
Running Performance ◽  
Total Distance ◽  
Professional Soccer ◽  
Performance Statistics ◽  
Game Performance

Running performance (RP) and game performance indicators (GPI) are important determinants of success in soccer (football), but there is an evident lack of knowledge about the possible associations between RP and GPI. This study aimed to identify associations between RP and GPI in professional soccer players and to compare RP and GPI among soccer playing positions. One hundred one match performances were observed over the course of half of a season at the highest level of national competition in Croatia. Players (mean ± SD, age: 23.85 ± 2.88 years; body height: 183.05 ± 8.88 cm; body mass: 78.69 ± 7.17 kg) were classified into five playing positions (central defenders (n = 26), full-backs (n = 24), central midfielders (n = 33), wide midfielders (n = 10), and forwards (n = 8). RP, as measured by global positioning system, included the total distance covered, distance covered in five speed categories (walking, jogging, running, high-speed running, and maximal sprinting), total number of accelerations, number of high-intensity accelerations, total number of decelerations, and number of high-intensity decelerations. The GPI were collected by the position-specific performance statistics index (InStat index). The average total distance was 10,298.4 ± 928.7 m, with central defenders having the shortest and central midfielders having the greatest covered distances. The running (r = 0.419, p = 0.03) and high-intensity accelerations (r = 0.493, p = 0.01) were correlated with the InStat index for central defenders. The number of decelerations of full-backs (r = −0.43, p = 0.04) and the distance covered during sprinting of forwards (r = 0.80, p = 0.02) were associated with their GPI obtained by InStat index. The specific correlations between RP and GPI should be considered during the conditioning process in soccer. The soccer training should follow the specific requirements of the playing positions established herein, which will allow players to meet the game demands and to perform successfully.

scholarly journals Effects of Different Post-Activation Potentiation Warm-Ups on Repeated Sprint Ability in Soccer Players from Different Competitive Levels

2018 ◽  
Vol 61 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Javier Sanchez-Sanchez ◽  
Alejandro Rodriguez ◽  
Cristina Petisco ◽  
Rodrigo Ramirez-Campillo ◽  
Cristian Martínez ◽  
...  
Keyword(s):  
Body Mass ◽  
High Speed ◽  
Body Height ◽  
Soccer Players ◽  
Meaningful Improvement ◽  
Warm Up ◽  
Performance Improvements ◽  
Repeated Sprint Ability ◽  
Repeated Sprint ◽  
Sprint Ability

Abstract This study aimed to compare the effects of a traditional warm-up with two post-activation potentiation (PAP) warm-up strategies on the repeated sprint ability (RSA) of soccer players from national (NL) and regional (RL) competitive levels. Sixteen young players (NL, n = 8, age = 20.7 ± 1.4 y, body mass = 68.5 ± 7.0 kg, body height = 177.4 ± 5.2 cm; RL, n = 8, age = 20.8 ± 1.0 y, body mass = 68.7 ± 4.0 kg, body height = 176.6 ± 5.6 cm) were recruited to complete a traditional warm-up (CONTROL), a PAP warm-up incorporating squats with a load (~60% 1RM) that allowed a high speed (1 m/s) of movement and a high number of repetitions (PAP-1), and a PAP warm-up with a load (~90% 1RM) that allowed a moderate speed (0.5 m/s) of movement and a reduced number of repetitions (PAP-0.5). A RSA test (six 20-m sprints with 20 s of recovery) was performed 5 min after the PAP warm-up to assess the effects of the different protocols on the fastest sprint (RSAb) and the mean time of all sprints (RSAm). A meaningful improvement of RSA performance was observed with PAP-0.5, attaining a large effect on NL (RSAb, ES = -1.5; RSAm, ES = -1.3) and only a small effect on RL athletes (RSAb and RSAm, ES = -0.2). Moreover, when each RSA sprint performance was compared between NL and RL players, after PAP-0.5 greater performance for all sprints was observed in the NL players. Therefore, adding a heavy strength-based conditioning exercise during the warm-up prior to a RSA test may induce significant performance improvements in NL, but only small effects in RL players.

scholarly journals Weekly Load Variations of Distance-Based Variables in Professional Soccer Players: A Full-Season Study

2020 ◽  
Vol 17 (9) ◽  
pp. 3300 ◽  
Author(s):  
Filipe Manuel Clemente ◽  
Rui Silva ◽  
Daniel Castillo ◽  
Asier Los Arcos ◽  
Bruno Mendes ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Speed ◽  
Training Load ◽  
Effect Sizes ◽  
Soccer Players ◽  
Load Variations ◽  
Total Distance ◽  
Professional Soccer ◽  
Moderate Effect ◽  
And Training

The aim of this study was two-fold: (1) to analyze the variations of acute load, training monotony, and training strain among early (pre-season), mid (first half of season), and end season (second half of season) periods; (2) to compare these training indicators for playing positions in different moments of the season. Nineteen professional players (age: 26.5 ± 4.3 years; experience as professional: 7.5 ± 4.3 years) from a European First League team participated in this study. The players were monitored daily over a 45-week period for the total distance (TD), distance covered (DC) at 14 km/h−1 or above (DC > 14 km/h), high-speed running above 19.8 km/h−1 (HSR) distance, and number of sprints above 25.2 km/h−1. The acute load (sum of load during a week), training monotony (mean of training load during the seven days of the week divided by the standard deviation of the training load of the seven days), and training strain (sum of the training load for all training sessions and matches during a week multiplied by training monotony) workload indices were calculated weekly for each measure and per player. Results revealed that training monotony and training strain for HSR were meaningfully greater in pre-season than in the first half of the in-season (p ≤ 0.001; d = 0.883 and p ≤ 0.001; d = 0.712, respectively) and greater than the second half of the in-season (p ≤ 0.001; d = 0.718 and p ≤ 0.001; d = 0.717). The training monotony for the sprints was meaningfully greater in pre-season than in the first half of in-season (p < 0.001; d = 0.953) and greater than the second half of in-season (p ≤ 0.001; d = 0.916). Comparisons between playing positions revealed that small-to-moderate effect sizes differences mainly for the number of sprints in acute load, training monotony, and training strain. In conclusion, the study revealed that greater acute load, training monotony, and training strain occurred in the pre-season and progressively decreased across the season. Moreover, external defenders and wingers were subjected to meaningfully greater acute load and training strain for HSR and number of sprints during the season compared to the remaining positions.

scholarly journals The Effect of Contextual Variables on Match Performance across Different Playing Positions in Professional Portuguese Soccer Players

2021 ◽  
Vol 18 (10) ◽  
pp. 5175
Author(s):  
Joel Barrera ◽  
Hugo Sarmento ◽  
Filipe Manuel Clemente ◽  
Adam Field ◽  
António J. Figueiredo
Keyword(s):  
Physical Performance ◽  
High Speed ◽  
Satellite System ◽  
Soccer Players ◽  
Physical Demands ◽  
Situational Variables ◽  
All Speeds ◽  
Global Navigation Satellite ◽  
Walking Speeds ◽  
Very High

This study investigated the position-specific physical demands of professional Portuguese players. The effects of situational variables on the physical performance demands were also analysed (match location, match half and match result). Match performance observations were collected using Global Navigation Satellite System devices across 11 matches during a competitive season (2019–2020). Data were analysed according to five playing positions: goalkeepers (n = 11), central defenders (n = 42), wide defenders (n = 31), central midfielders (n = 34), open attackers (n = 28), and centre forwards (n = 14). Central midfield players completed the greatest total distance (10,787 ± 1536 m), while central defenders covered the least distance (9272 ± 455; p < 0.001). Open attackers covered the greatest high and very-high-speed distance (1504 ± 363 m), number of high-speed decelerations per match (11 ± 4) and were the fastest players (30.6 ± 1.5 km/h), along with center forwards (30.6 ± 2.0 km/h), versus all other positions (p < 0.05). Greater distances were performed in teams that were winning (9978 ± 1963 m) or drawing (10,395 ± 875 m) versus losing (9415 ± 2050) p = 0.036 and p = 0.006, respectively. Increases in distance covered at walking speeds were observed during the 2nd half (1574 ± 179 m) compared with the 1st half (1483 ± 176; (p < 0.003). A higher number of decelerations across all speeds were performed in the 1st half (144 ± 39) versus the 2nd half (135 ± 37). The distance covered in home matches (10,206 ± 1926 m) far exceeded away matches (9471 ± 1932 m; p < 0.001). The number of faster accelerations were higher in away (7 ± 5) versus home matches (6 ± 4; p < 0.049). The data demonstrate the different physical demands of each playing position and suggest that situational variables influence physical performance. These findings suggest position-specific physical training is required to condition players for the bespoke demands of each playing position.

scholarly journals The Reliability and Sensitivity of Change of Direction Deficit and Its Association with Linear Sprint Speed in Prepubertal Male Soccer Players

2021 ◽  
Vol 6 (2) ◽  
pp. 41
Author(s):  
Senda Sammoud ◽  
Raja Bouguezzi ◽  
Yassine Negra ◽  
Helmi Chaabene
Keyword(s):  
Intraclass Correlation ◽  
Soccer Players ◽  
Time Interval ◽  
Sprint Speed ◽  
Change Of Direction ◽  
Speed Test ◽  
Typical Error ◽  
M 10 ◽  
The Mean ◽  
Error Of Measurement

Background: This study aimed to examine the reliability and sensitivity of a change of direction deficit (CoDD) and to establish its relationship with linear sprint speed. Methods: In total, 89 prepubertal male soccer players participated in this study (age = 11.7 ± 1.2 years, maturity offset = −2.4 ± 1.0). Participants performed the 505 CoD speed test and the 20 m linear sprint speed test with a split interval at 5 m and 10 m. The CoDD was calculated as the mean 505 CoD time—the mean 10 to 20 m time interval. To evaluate the reliability of CoDD, the 505 CoD speed test, and 20 m linear sprint speed were performed twice, one week apart. The sensitivity of CoDD was identified by comparing the values of the typical error of measurement (TEM) and smallest worthwhile change (SWC). Results: Results of the reliability analysis indicated an intraclass correlation coefficient (ICC3.1) < 0.50 (0.47) and a TEM expressed as the coefficient of variation > 5% (10.55%). The sensitivity analysis showed that the ability of the CoDD measure to detect small performance changes is “marginal” (TEM (0.12) > SWC0.2 (0.04)). However, good absolute and relative reliability were observed for the 505 CoD speed test (ICC3.1 = 0.75; TEM < 5%). Alike CoDD, the ability of the 505 CoD speed test to detect small performance changes was rated as “marginal” (TEM (0.07 s) > SWC0.2 (0.04 s)). The CoDD revealed a large association with the 505 CoD speed test (r = 0.71). However, non-significant associations were detected between the CoDD and 5 m, 10 m, and 20 m linear sprint speed intervals (r = 0.10 to 0.16, all p > 0.05). Likewise, non-significant correlations between the 505 CoD speed test and 5 m, 10 m, and 20 m linear sprint speed intervals were observed (r = 0.14 to 0.20, all p > 0.05). Conclusions: The CoDD displayed poor reliability and limited ability to detect small changes in performance in prepubertal male soccer players. Due to its limited practical utility, practitioners are advised not to consider CoDD scores during the assessment of prepubertal male soccer players.

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