Competitive Football Match Research Articles

Influence of a football match on landing biomechanics and jump performance in female football players.

This study aimed to assess the acute effect of a competitive football match on jump performance and kinematic parameters during jump landing in semiprofessional female football players. Twenty-two semiprofessional players (20 ± 3 years) underwent a drop jump task for a posterior video analysis of the landing phase. These measurements were obtained at (1) baseline, (2) after, and (3) 48 h after a competitive football match. A one-way ANOVA with repeated measures was employed to detect differences over the time. There was a main effect of time for maximal knee flexion angle during drop landing (p = 0.001). In comparison with baseline, maximal knee flexion angle was reduced immediately post-match and was still reduced 48 h after the match (63.4 ± 8.6 vs 57.0 ± 11.7 vs 48.9 ± 19.1, p ≤ 0.038). There was also a main effect of time for drop jump height (p < 0.001). Drop jump height was reduced immediately post-match and remained low 48 h after the match in comparison with baseline (27.3 ± 3.6 vs 24.5 ± 2.8 ~ 25.5 ± 3.0 cm, p ≤ 0.002). There was a main effect of time on hip flexion angle during landing (p = 0.001), but the pairwise comparison revealed that this variable was not affected immediately post-match but was lower 48 h after the match than at baseline (50.1 ± 10.1 ~ 50.8 ± 13.2 vs 38.1 ± 17.8 °, p ≤ 0.005). A competitive football match worsened jump performance and several landing biomechanical parameters in female football players, which were still decreased in comparison with baseline even 48 h after the match.

Highlighting Shooting Opportunities in Football.

The purpose of the present study was to create a two-dimensional model which illustrates a landscape of shooting opportunities at goal during a competitive football match. For that purpose, we analysed exemplar attacking subphases of each team when the ball was in the last 30 m of the field. The player's positional data (x and y coordinates) and the ball were captured at 25 fps and processed to create heatmaps that illustrated the shooting opportunities that were available in the first and second half in different field areas. Moreover, the time that the shooting opportunities were available was estimated. Results show that in the observed match, most of the shooting opportunities lasted between 1 and 2 s, with only a few opportunities lasting more than 2 s. The shooting opportunities did not display a homogenous distribution over the field. The obtained heatmaps provide valuable and specific information about each team's shooting opportunities, allowing the identification of the most vulnerable areas. Additionally, the amount, duration, and location of the shooting opportunities have shown significant differences between teams. This customizable model is sensitive to the features of shooting opportunities and can be used in real-time video analysis for individual and collective performance analysis.

Illustrating changes in landscapes of passing opportunities along a set of competitive football matches

This study aims to illustrate the landscape of passing opportunities of a football team across a set of competitive matches. To do so positional data of 5 competitive matches was used to create polygons of pass availability. Passes were divided into three types depending on the hypothetical threat they may pose to the opposing defense (penetrative, support, and backwards passes). These categories were used to create three heatmaps per match. Moreover, the mean time of passing opportunities was calculated and compared across matches and for the three categories of passes. Due to the specificity of player’s interactive behavior, results showed heatmaps with a variety of patterns. Specifically the fifth match was very dissimilar to the other four. However, characterizing a football match in terms of passing opportunities with a single heatmap dismisses the variety of dynamics that occur throughout a match. Therefore, three temporal heatmaps over windows of 10 min were presented highlighting on-going dynamical changes in pass availability. Results also display that penetrative passes were available over shorter periods of time than backward passes that were available shorter than support passes. The results highlight the sensibility of the model to different task constrains that emerge within football matches.

Video assistant referees (VAR): The impact of technology on decision making in association football referees

ABSTRACT The use of technology has been proposed to improve decision-making in sport officials. The implementation of the video Assistant Referee (VAR) in association football is one example of how technology can be used to assist decision making, although its impact remains unknown. In 2195 competitive football matches across 13 countries, the VAR conducted 9732 checks for potential match-changing incidents, with the median duration of a check being 22 seconds. The checks resulted in a total of 795 reviews, with a median duration of 62.0 s for on-field reviews (N = 534) and 15.0 s for VAR-only reviews (N = 261).We report that the predictive odds for making the correct decision after VAR intervention were significantly higher than for the initial referee’s decision, with accuracy increasing from 92.1% to 98.3%. Findings have implications for the current debate about the introduction of technology in association football and may help set guidelines regarding the use of technology across other sports and professional domains.

Plasma oxidative stress (hydrogen peroxide/trolox) responses during a 7-day road cycling stage race and a competitive football match in top-level athletes

The aim of this study was to compare the response induced by regular competition on free oxygen radicals (hydrogen peroxide), free oxygen radical defence (Trolox) and hydrogen peroxide/Trolox balance in plasma, between top-level male road cyclists and top-level male football players. 9 male top-level road cyclists (age 27.2 ± 3.5 years) and 10 male top-level football players (age 27.3 ± 4.3 years) completed a 7-day road cycling stage race and a football match, respectively. Free oxygen radicals (hydrogen peroxide) and free oxygen radical defence (Trolox) were measured 2 h before and 1 h after the corresponding competition. Body composition was determined previously by means of dual-energy X-ray absorptiometry. Both competitions induced a significant increase in hydrogen peroxide for each group. Trolox decreased and hydrogen peroxide/Trolox balance increased, significantly, for road cyclists. For football players, Trolox increased and hydrogen peroxide/Trolox balance decreased, significantly. Hydrogen peroxide/Trolox balance differences had a significant positive correlation against respective competitive loads for both groups. Hydrogen peroxide differences showed a significant negative correlation and Trolox differences indicated a significant positive correlation with body mass index, body fat, and lean body mass. This study suggests that football players may be able to maintain oxidative stress balance in plasma after a football match whilst road cyclists may experience a hyper-oxidative stress state in plasma after a 7-day road cycling stage race. In addition, both, competitive load and body mass are related to the oxidative stress balance in plasma in these two groups of top-level athletes.

C-Reactive Protein Serum Levels as an Internal Load Indicator of Sprints in Competitive Football Matches.

This study compared internal load variable dynamics across three consecutive football matches and investigated its relationship with the number of sprints performed by players. Twenty-three male players had blood and salivary samples collected for hormonal concentration (testosterone, cortisol, and testosterone-cortisol ratio), and serum analysis (interleukin-6, interleukin-1-beta, and c-reactive-protein), respectively. Sprints were measured through Global Position System devices. Testosterone and testosterone-cortisol-ratio presented a decreasing behavior up to the second match, and all other indicators presented an increasing behavior during the same period, c-reactive-protein was the only indicator observed to significantly rise up to the third match as well (0.38±0.02 mg/L; 0.49±0.05 mg/L; 0.69±0.05 mg/L; 0.89±0.08 mg/L). C-reactive-protein showed strong correlations with sprints in the second and third matches (p<0.01, r=0.71 and 0.79), and weak-to-moderate in the first one (p<0.05, r=0.59). Interleukin-6 and interleukin-1-beta presented weak-to-moderate correlation in every match (p<0.05, r=0.48 to 0.51; r=0.51 to 0.55) while testosterone-cortisol ratio presented weak-to-moderate correlation only in the third one (p<0.05, r=0.42). Multilevel linear regression showed that c-reactive-protein had a higher R2 than other biomarker in any regression model (R2=0.624; p<0.001). Therefore, c-reactive-protein can be a valid and reliable indicator of sprinting in competitive football. Future research should explore longer periods of monitoring and/or others external load variables so that other behaviors may arise to knowledge.

Monitoring the effect of football match congestion on hamstring strength and lower limb flexibility: Potential for secondary injury prevention?

ObjectivesTo investigate the effect of competitive football match congestion on hamstring strength and lower limb flexibility. DesignRepeated measures. SettingElite male youth football. ParticipantsFifteen male elite youth football players from the national football association centre of excellence were included (age = 15.81 ±0.65 years, height = 171.95 ±6.89 cm, weight = 65.93 ±7.53 kg). Main outcome measuresHamstring strength and pain, ankle dorsiflexion, hip extension, knee extension and flexion range of motion. ResultsHamstring strength was highest at baseline and significantly reduced at 24 (p = 0.001, mean difference −0.19 Nm/Kg, CI95 −0.28, −0.1) and 48 h post-match 1 (p = 0.002, mean difference −0.16 Nm/Kg, CI95 −0.25, −0.07). Strength recovered by match day 2 before significantly reducing again 24 h post-match 2 (p = 0.012, mean difference −0.17 Nm/Kg, CI95 −0.29, −0.04). Pain was lowest at baseline and increased in the post-match periods (p < 0.05) with standardised effect sizes ranging from 0.07 to 0.42. Passive knee flexion range decreased post-match (p < 0.01) with mean differences of 1.5°–2.7°. The other flexibility measures remained unaffected by match play. ConclusionIsometric hamstring strength and pain can be considered for inclusion in-season to monitor player's post-match hamstring recovery characteristics during congested match fixtures.

The acute effect of match play on hamstring strength and lower limb flexibility in elite youth football players.

The aim of this study was to investigate the effect of competitive football match play on hamstring strength and lower limb flexibility. Fifteen male international youth football players were included. Hamstring strength and associated pain ratings, ankle dorsiflexion, hip extension, knee extension and flexion range of motion were evaluated immediately post-match and at intervals of 24, 48, and 72h post-match. Strength significantly reduced post-match (P<0.01), mean difference -0.43 (CI95 : -0.56, -0.30) and 24h post (P<0.05) mean difference -0.12Nm/kg (CI95 : -0.20, -0.04). The associated pain scores significantly increased at the post-match (P<0.01, ES=0.61) and 24h (P<0.01, ES=0.55) time intervals. At the 48 and 72h post-match tests no significant difference was found for strength or pain ratings. No significant differences were detected for any of the range of motion measures. Competitive football match play has a significant acute and transient effect on isometric hamstring strength and associated pain levels during resisted knee flexion in male international youth players. Range of motion measures appear to remain relatively unaffected by match play. Isometric hamstring strength testing and associated pain levels might be considered for inclusion in-season to monitor player's post-match hamstring recovery characteristics.

Joint-position sense is altered by football pre-participation warm-up exercise and match induced fatigue

BackgroundThe demands to which football players are exposed during the match may augment the risk of injury by decreasing the sense of joint position. This study aimed to assess the effect of pre-participation warm-up and fatigue induced by an official football match on the knee-joint-position sense of football players. MethodsFourteen semi-professional male football players (mean age: 25.9±4.6years old) volunteered in this study. The main outcome measures were rate of perceived exertion and knee-joint-position sense assessed at rest, immediately after a standard warm-up (duration 25min), and immediately after a competitive football match (90minutes duration). ResultsPerceived exertion increased significantly from rest to the other assessments (rest: 8.6±2.0; after warm-up: 12.1±2.1; after football match: 18.5±1.3; p<0.001). Compared to rest, absolute angular error decreased significantly after the warm-up (4.1°±2.2° vs. 2.0°±1.0°; p=0.0045). After the match, absolute angular error (8.7°±3.8°) increased significantly comparatively to both rest (p=0.001) and the end of warm-up (p<0.001). Relative error showed directional bias with an underestimation of the target position, which was higher after the football match compared to both rest (p<0.001) and after warm-up (p<0.001). ConclusionsThe results indicate that knee-joint-position sense acuity was increased by pre-participation warm-up exercise and was decreased by football match-induced fatigue.Clinical relevance: Warm-up exercises could contribute to knee injury prevention, whereas the deleterious effect of match-induced fatigue on the sensorimotor system could ultimately contribute to knee instability and injury.

Reliability and sensitivity of a simple isometric posterior lower limb muscle test in professional football players

This study aimed (1) to determine the reliability of a simple and quick test to assess isometric posterior lower limb muscle force in professional football players and (2) verify its sensitivity to detect reductions in force following a competitive match. Twenty-nine professional football players performed a 3-s maximal isometric contraction of the posterior lower limb muscles for both legs with players lying supine. Both legs were tested using a knee angle of 90° and 30° measured on a force plate. Players were tested twice with one week between sessions to verify reliability. Sensitivity was tested following a full competitive football match. The test showed high reliability for dominant leg at 90° (CV = 4.3%, ICC = 0.95, ES = 0.15), non-dominant leg at 90° (CV = 5.4%, ICC = 0.95, ES = 0.14), and non-dominant leg at 30° (CV = 4.8%, ICC = 0.93, ES = 0.30) and good reliability for dominant leg at 30° (CV = 6.3%, ICC = 0.86, ES = 0.05). The measure was sensitive enough to detect reductions in force for dominant leg at 90° (P = 0.0006, ES > 1), non-dominant leg at 90° (P = 0.0142, ES = 1), and non-dominant leg at 30° (P = 0.0064, ES > 1) and for dominant leg at 30° (P = 0.0016, ES > 1). In conclusion, the present test represents a useful and practical field tool to determine the magnitude of match-induced fatigue of the posterior lower limb muscles and potentially to track their recovery.

Half-Time and High-Speed Running in the Second Half of Soccer

This study investigated if the quantity of high-speed running (movements >15 km.h(-1) completed in the first 15 min of competitive football matches differed from that completed in the corresponding 15 min of the second half. 20 semi-professional soccer players (age 21.2±3.6 years, body mass 76.4±3.8 kg, height 1.89±0.05 m) participated in the study. 50 competitive soccer matches and 192 data files were analysed (4±2 files per match) using Global Positioning Satellite technology. Data were analysed using 2-way repeated measures ANOVA and Pearson correlations. No differences were found between the first 15 min of each half for the distance completed at high-speed (>15 km.h(-1) or sprinting (>21 km.h(-1), or in the number of sprints undertaken (p>0.05). However, total distance covered was shorter (1st half vs. 2nd half: 1746±220 vs. 1644±224 m; p<0.001) and mean speed lower (1st half vs. 2nd half: 7.0±0.9 vs. 6.6±0.9 km.h(-1); p<0.001) in the first 15 min of the second half compared to the first. The correlations between the duration of the half-time interval and the difference in the high-speed running or sprinting between first and second halves (0-15 min) were very small (r=0.08 [p=0.25] and r=0.04 [p=0.61] respectively). Therefore, this study did not find any difference between the amount of high-speed running and sprinting completed by semi-professional soccer players when the first 15 min of the first and second half of competitive matches were compared The maintenance of high-speed running and sprinting, as total distance and mean speed declined, may be a function of the pacing strategies adopted by players in competitive matches.

Changes in core temperature and hydration status during a competitive football match played in cool conditions

Football is played throughout the world in a wide range of environmental conditions. Thermal responses to match play in temperate and warm conditions have been widely reported, but there little...

Water Balance and Salt Losses in Competitive Football

Fluid balance and sweat electrolyte losses were measured in the players and substitutes engaged in an English Premier League Reserve competitive football match played at an ambient temperature of 6-8 degrees C (relative humidity 50-60%). Intake of water and/or sports drink and urine output were recorded, and sweat composition was estimated from absorbent swabs applied to 4 skin sites for the duration of the game. Body mass was recorded before and after the game. Data were obtained for 22 players (age 21 y, height 180 cm, mass 78 kg) and 9 substitutes (17 y, 181 cm, 72 kg). All were male. Two of the players were dismissed during the game, and none of the substitutes played any part in the game. Mean +/- SD sweat loss of players amounted to 1.68 +/- 0.40 L, and mean fluid intake was 0.84 +/- 0.47 L (n = 20), with no difference between teams. Corresponding values for substitutes, none of whom played in the match, were 0.40 +/- 0.24 L and 0.78 +/- 0.46 L (n = 9). Prematch urine osmolality was 678 +/- 344 mOsm/kg: 11 of the 31 players provided samples with an osmolality of more than 900 mOsm/kg. Sweat sodium concentration was 62 +/- 13 mmol/L, and total sweat sodium loss during the game was 2.4 +/- 0.8 g. These descriptive data show a large individual variability in hydration status, sweat losses, and drinking behaviors in a competitive football match played in a cool environment, highlighting the need for individualized assessment of hydration status to optimize fluid-replacement strategies.

Grade III acromioclavicular joint injury in Australian Rules Football

We have reviewed fourteen Australian Rules Football players who were seen consecutively by a single surgeon with grade III acromioclavicular joint injuries between January 1993-June 1997. After discussion at initial consultation eight players elected for non-operative management and six for operative management. Two players in the non-operative group subsequently underwent surgical reconstruction after failure of non-operative treatment. The mean return time to non-contact training was 2.4 weeks (range 1-4, S.D. 1.52) in the non-operative group and 6.3 weeks (range 3.5-10, S.D. 2.99) in the operative group. However return to sports specific training (contact training) was at a mean of 20.8 weeks (range 10-32. S.D. 8.56) in the non-operative group and 13.6 weeks (range 6-24. S.D. 7.06) in the operative group. Return to competitive football matches for the non-operative group was at a mean of 26.2 weeks (range 10-34,S.D. 8.84) and 18.8 weeks (9.5-28. S.D. 8.05) for those treated operatively. These results were not statistically significant. At final follow up the subjective scores for the current overall condition of the shoulder when compared to the uninjured side, were 72.5 (range 20-100, S:D.24.9) for the non operative group and 87.3 (range 75-100, S:D.10.61) for the operative group and this difference was also not statistically significant. Conclusions in this study are limited by small numbers and lack of statistically significant results. The results show a trend towards faster return to ARF and a more satisfactory outcome for patients undergoing surgery compared to their non operative cohorts.