Javier Mallo

Technical and physical demands of small vs. large sided games in relation to playing position in elite soccer

The aim of this investigation was to compare the effects of common rule changes on technical and physical demands for elite soccer players in five playing positions during various 4-min small-sided games (SSGs) in comparison to 11-a-side matches. Forty international players classified into five positional roles participated in the study (25.3±2.4 years, 182.4±2.3 cm, 77.3±4.1 kg; M±SD). Players completed three different conditioned small-sided 4 vs. 4 games (1 ball touch=1T, 2 ball touches=2T and Free Play=FP) as well as two friendly matches. Heart rate (HR), blood lactate ([La]), ratings of perceived exertion (RPE) as well as physical and technical performance were analyzed. Compared to match-play, total distance covered per minute of play, high-intensity running activities (sprinting and high-intensity runs), total numbers of duels and lost ball possessions were significantly greater within SSGs for all playing positions (p<.05). In contrast, [La], percentage of successful passes and number of ball possessions were lower (p<.05) within SSGs, particularly with 1T and 2T rules, in comparison with match-play. HR was higher in SSGs compared to match-play for all playing positions, and RPE values were lower (p<.05) during the FP SSG for defensive midfielders, wide midfielders and forwards. In conclusion, this study revealed that 4 vs. 4 SSGs played with 1 or 2 ball touches increased the high-intensity running and the difficulty to perform technical actions, being more specific to match demands. Subsequently, it is of importance for coaches to understand the different physiological demands imposed upon players by varying the rules of SSGs and to understand the differences between positional roles.

Activity profile of top-class association football referees in relation to performance in selected physical tests

Abstract The aims of the present study were (1) to analyse the physical demands of top-class referees and (2) to compare their official FIFA fitness test results with physical performance during a match. The work rate profiles of 11 international referees were assessed during 12 competitive matches at the 2003 FIFA Under-17 World Cup and then analysed using a bi-dimensional photogrammetric video analysis system based on direct lineal transformation (DLT) algorithms. In the first 15 min of matches, the referees were more active, performing more high-intensity exercise (P < 0.01) than in the first 15 min of the second half. During the second half of matches, the referees covered a shorter distance (P < 0.01), spent more time standing still (P < 0.05), and covered less ground cruising (P < 0.05), sprinting (P < 0.05), and moving backwards (P < 0.001) than in the first half. Also in the second 45 min, the distance of referees from infringements increased (P < 0.05) in the left attacking zone of the filed. There was also a decrease (P < 0.05) in performance in the period following the most high-intensity activity, compared with the mean for the 90 min. Time spent performing high-intensity activities during a match was not related to performance in the 12-min run (r 2 = 0.30; P < 0.05), the 200-m sprint (r 2 = 0.05; P < 0.05), or the 50-m sprint (r 2 = 0.001; P < 0.05). The results of this study show that: (1) top-class referees experienced fatigue at different stages of the match, and (2) the typical field tests used by FIFA (two 50-m and 200-m sprints, followed by a 12-min run) are not correlated with match activities.

Effect of positioning on the accuracy of decision making of association football top-class referees and assistant referees during competitive matches

Abstract The aim of this study was to examine the effect of positioning on the correctness of decision making of top-class referees and assistant referees during international games. Match analyses were carried out during the Fédération Internationale de Football Association (FIFA) Confederations Cup 2009 and 380 foul play incidents and 165 offside situations were examined. The error percentage for the referees when indicating the incidents averaged 14%. The lowest error percentage occurred in the central area of the field, where the collaboration of the assistant referee is limited, and was achieved when indicating the incidents from a distance of 11–15 m, whereas this percentage peaked (23%) in the last 15-min match period. The error rate for the assistant referees was 13%. Distance of the assistant referee to the offside line did not have an impact on the quality of the offside decision. The risk of making incorrect decisions was reduced when the assistant referees viewed the offside situations from an angle between 46 and 60°. Incorrect offside decisions occurred twice as often in the second as in the first half of the games. Perceptual-cognitive training sessions specific to the requirements of the game should be implemented in the weekly schedule of football officials to reduce the overall error rate.

Analysis of the kinematical demands imposed on top-class assistant referees during competitive soccer matches.

The aim of this study was to describe the kinematical demands placed on soccer assistant referees during the 2003 U-17 World Championship, and to examine the relationship between the results in the fitness tests adopted by FIFA and match activities. Twenty-two international-level assistant referees were observed during 12 matches and computerized analysis of match activities was performed using a two-dimensional photogrammetric video analysis system based on DLT (direct lineal transformation) algorithms. Before the start of the tournament, the assistant referees completed a 2 × 50-m sprint test and a 12-minute run test. Assistant referees covered on average 6137 ± 539 m during the matches, with 20% of the total distance covered at high velocities (speeds faster than 13 km·h−1). During the second half, time spent standing still increased (P < 0.01) and distance covered jogging (P < 0.05), cruising (P < 0.01) and moving sideways (P < 0.001) decreased. The score in the 12-minute run test showed a low correlation with the entire match distance (r = 0.24; P > 0.05) and with the time spent exercising at a high intensity (r = 0.35; P > 0.05). The 50-m sprint time was not significantly correlated (r = −0.38; P > 0.05) with time spent within the high-intensity activities category. The results of this study demonstrate that assistant referees experience unique kinematical demands during soccer officiating and that the score in the battery of fitness tests adopted by FIFA was not correlated to match activities.

Physical Demands of Top-class Soccer Assistant Refereeing during High-standard Matches

This study examined the physical demands experienced by top-class assistant referees during high-standard football matches. Computerized match analyses and heart rate recordings were performed on 18 international assistant referees during the FIFA Confederations Cup 2005. Total distance covered averaged 5752+/-554 m, of which 34% was covered at a high-intensity (>13 km.h (-1)). Sidewards movements represented 30% of total match distance. Both total distance (r=0.67; P<0.01) and high-intensity activities (r=0.52; P<0.05) were related to the displacements of the ball in the same match. The distance covered by high-speed running in this tournament was 255% greater (P<0.001) than that covered during the under-17 World Championship 2003. Mean heart rate during the game was 140+/-11 b.min (-1) (78+/-4% HR (max)). Mean heart rate during a 5-min interval of the match was related in part (r=0.31; P<0.001) to the amount of high-intensity activities performed within the same match-period. The results of this study show that the physical demands imposed on assistant referees are influenced by the movements of the ball and the standard of the competition.

Biomechanical analysis of the penalty-corner drag-flick of elite male and female hockey players

The aim of this study was to analyse the kinematic sequencing in the penalty-corner drag-flicks of elite male and female field hockey players of international calibre. Thirteen participants (one skilled male drag-flicker and six male and six female elite players) participated in the study. An optoelectronic motion analysis system was used to capture the drag-flicks with six cameras, sampling at 250 Hz. Select ground reaction force parameters were obtained from a force platform which registered the last support of the front foot. Twenty trials were captured from each subject. Both player groups showed significantly (p < 0.05) smaller ball velocity at release, peak angular velocity of the pelvis, and negative and positive peak angular velocities of the stick than the skilled subject. Normalised ground reaction forces of the gender groups were also smaller than that of the skilled drag-flicker. By comparing these players we established that the cues of the skill level are a wide stance, a whipping action (rapid back lift) of the stick followed by an explosive sequential movement of the pelvis, upper trunk and stick.

Effect of block periodization on performance in competition in a soccer team during four consecutive seasons: A case study

The purpose of this study was to examine the effect of applying block periodization on performance in competition in a Spanish professional soccer team during four consecutive seasons. A longitudinal training protocol was designed, structuring each season into three training stages which were further subdivided into three training blocks or mesocycles (Accumulation, Transmutation and Realization), where the physical conditioning was focused on a minimal number of physical capacities. To examine training workloads, time spent developing each physical capacity was compared within blocks. To assess team performance in competition, the percentage of points obtained by the team in each match (points obtained/points in play; 3 points per victory, 1 point per draw; 0 points per defeat) was examined in relation to the training block. Time employed developing high-intensity aerobic (P<0.001) and gym-based strength (P<0.05) was higher in Accumulation, speed endurance (P<0.05) in Transmutation, and speed (P<0.05) in Realization. The highest success percentage in competition was achieved during Realization blocks (χ2(2)=6.23; P<0.05), where the team obtained 59% of the points in play. The results of this study show that block periodization can be an alternative training design for professional soccer teams. Competitive team performance was greater during Realization blocks.

Effects of different swimming race constraints on turning movements

The aim of this study was to investigate the effects of different swimming race constraints on the evolution of turn parameters. One hundred and fifty-eight national and regional level 200-m (meters) male swimming performances were video-analyzed using the individualized-distance model in the Open Comunidad de Madrid tournament. Turn (p<.001, ES=0.36) and underwater distances (p<.001, ES=0.38) as well as turn velocity (p<.001, ES=0.69) significantly dropped throughout the race, although stroke velocity and underwater velocity were maintained in the last lap of the race (p>.05). Higher expertise swimmers obtained faster average velocities and longer distances in all the turn phases (p<.001, ES=0.59), except the approach distance. In addition, national level swimmers showed the ability to maintain most of the turn parameters throughout the race, which assisted them in improving average velocity at the end of races. Therefore, the variations in the turning movements of a swimming race were expertise-related and focused on optimizing average velocity. Turning skills should be included in the swimming race action plan.

A new procedure for race analysis in swimming based on individual distance measurements

Abstract The aim of this study was to develop a new application based on the “individual distances” method to analyse swimming races, and to compare it with the traditional “fixed distances” method. One hundred and seventy-nine national level 100 m (four strokes) performances obtained from the 2008 “Open Comunidad de Madrid” (Spain) were analysed using a two-dimensional Direct Linear Transformation (2D-DLT) video analysis system. Average velocities in all race segments (P < 0.001) were faster using the “individual distances” method than when employing the “fixed distances” method. Specifically, start and turn times were shorter (P < 0.001) while free swimming times were longer (P < 0.001) when using the “individual distances” method. Correlations between methods were moderate to high, but several gender and stroke groups showed poor to no correlation, especially during the start and turn segments. Differences between methods were higher in some groups (female swimmers and freestyle stroke) where the start and turn distances were shorter. Measurements with the 2D-DLT technique provide distances and times employed during the race segments, which do not completely agree with times at fixed distances. Therefore, when evaluating swimming races, a combination of the individual and fixed distances methods should be used.

Effect of block periodization on physical fitness during a competitive soccer season

This study examined the effect of block periodization on physical fitness in a professional soccer team. Twenty two male players (21.9 ± 2.3 years) were followed in the course of the 2007-2008 season. The season was divided into five training stages which were further subdivided into three consecutive blocks (Accumulation, Transmutation and Realization) where physical workloads focused on a minimal number of capacities. To examine the training volume, time spent developing physical capacities relevant for soccer’s match performance was compared within each block. To study training intensity, heart rate was recorded during all training sessions and compared within blocks. Measures of physical characteristics and physical fitness were assessed in every training stage. Time spent performing high-intensity aerobic training was predominant (P<0.001) in Accumulation in relation to Transmutation and Realization blocks. In addition, time devoted to speed endurance training was higher (P<0.01) in Transmutation than in Accumulation and Realization, whereas time spent developing speed was superior (P<0.05) in Realization in comparison to Accumulation and Transmutation. Vertical jumping height and 10-m sprinting time improved (P<0.01) in the last training stage in relation to the initial values. The players covered a 26-30% greater distance (P<0.001) in the yo-yo intermittent recovery level-1 test at the end than at the beginning of the competitive period. These results suggest that block periodization can be an alternative design for soccer training.