Karim Chamari and Roald Bahr
Karim Chamari and Ralph Beneke
Monoem Haddad, Johnny Padulo and Karim Chamari
Despite various contributing factors, session rating of perceived exertion has the potential to affect a large proportion of the global sporting and clinical communities since it is an inexpensive and simple tool that is highly practical and accurately measures an athlete’s outcome of training or competition. Its simplicity can help optimize performance and reduce negative outcomes of hard training in elite athletes.
Montassar Tabben, Bianca Miarka, Karim Chamari and Ralph Beneke
Purpose: To evaluate the concept of decisive moment (DM) as a novel analysis approach providing insights into factors leading to successful high-performance k umite karate outcomes using time–motion variables. DM represents the moment from which 1 of the 2 opponents uninterruptedly dominates the other until the end of the fight. Methods: A total of 120 elite seniors (60 men and 60 women) World Karate Federation combats were analyzed during 2 World Championships (2012 and 2014). Specific characteristics of karate combat (strategy, technique, tactic, target, and effectiveness) were evaluated and classified in 3 sections: at, before, and after DM. Results: DM occurred at about 49% (32.8%) of bout duration. Up to DM no clearly identifiable differences in performance characteristics were found between winners and losers. At and after DM, an offensive strategy with focus on upper-limb techniques, attack and counterattack, targeting the head showed highest potential to achieve and maintain dominance and to win. After DM, losers showed increasingly reactive techniques, mainly timed attacks and combinatory techniques. Conclusion: The DM concept presents a novel approach to time–motion analysis, which for the first time allowed identification of clear discriminating factors of success and defeat in kumite karate at the highest performance level.
Montassar Tabben, Daniele Conte, Monoem Haddad and Karim Chamari
Purpose: To assess the technical and tactical demands of elite karate athletes in relation to 3 match sequences (ie, advantage, disadvantage, and drawing) and match outcome (ie, win/defeat).Methods: One hundred twenty elite seniors’ (60 men and 60 women) World Karate Federation combats were analyzed during 2 World Championships (2012 and 2014). Specific karate attributes (strategy, technique, tactic, target, and effectiveness) were evaluated and classified into 3 sequences: advantage, disadvantage, and drawing. Results: Karatekas performed more combination techniques in disadvantage sequences than in drawing sequences (P = .011). A higher number of timed-attack actions were reported during advantage sequences than during drawing sequences (P = .048). Winners of the whole combat had higher lower-limb technique rate (1.0 [0.9] vs 0.1 [0.3]; P = .044) and less rate of timed attack (0.3 [0.5] vs 0.6 [1.0]; P = .030) than defeated karatekas during advantage and drawing sequences, respectively. Conclusions: Winners used higher lower-limb technique and less timed-attack rates than defeated karatekas in advantage and drawing sequences, respectively. Indeed, using lower-limb technique during advantageous situations could be a powerful strategy to increase the lead. Therefore, it seems fundamental for coaches of top elite karatekas to put their athletes in simulated situations and push them to increase their use of lower-limb techniques.
Maamer Slimani, Helmi Chaabene, Bianca Miarka and Karim Chamari
To determine the performance aspects (time–motion and technical-tactical analysis) of top-level low-kick kickboxers according to gender, weight category, combat round, and match outcome.
Seventy-two kickboxers (44 male, 28 female) were studied. Thirty-six bouts (male = 61, female = 41 rounds) were analyzed using a time–motion system. Time structure was classified into 3 phases: preparatory-activity time (PT), fighting time (FT), and stoppage time (ST).
Referee decisions caused an overall effort:pause ratio (E:P) of ~1:1.5, with a significant difference between weight categories (light and middleweights = 1:1.5, heavyweight = 1:1). This ratio was ~1:6 when high-intensity actions–to-pause activities were considered. Significant differences were also observed between rounds (all P < .001), with 1st-, 2nd-, and 3rd-round E:Ps of 1:1, 1:1.5, and ~1:2, respectively. The relative times of FT and PT, total attacking actions, upper-limb actions, number of technical actions performed on the head, and the number of high-intensity actions were higher in males than females (all P = .05). Males performed more jab-cross actions and fewer low kicks than females (P < .001). Males used upper-limb (63.4%) more than lower-limb techniques (36.6%), targeting the head (56.9%) more than the body/leg (43.1%), with no significant difference from females (P > .05). E:P was similar between winners and losers. However, the numbers of technical actions performed on the head, counterattack actions, jab-cross technique, and total punches were higher in winners than losers (all P < .05).
Training programs need to be adapted to the specific requirements of kickboxers’ weight categories and gender to develop the technical-tactical abilities that improve athletes’ chances of winning.
Alexandre Dellal, Carlos Lago-Penas, Del P. Wong and Karim Chamari
The aim of this study was to examine the influence of the number of ball touches authorized per possession on the physical demands, technical performances and physiological responses throughout the bouts within 4 vs. 4 soccer small-sided games (SSGs).
Twenty international soccer players (27.4 ± 1.5 y, 180.6 ± 2.3 cm, 79.2 ± 4.2 kg, body fat 12.7 ± 1.2%) performed three different 4 vs. 4 SSGs (4 × 4 min) in which the number of ball touches authorized per possession was manipulated (1 touch = 1T; 2 touches = 2T; Free Play = FP). The SSGs were divided in 4 bouts (B1, B2, B3 and B4) separated by 3 min of passive recovery. The physical performances, technical activities, heart rate responses, blood lactate and RPE were analyzed.
The FP rule presented greater number of duels, induced the lowest decreases of the sprint and high-intensity performances, and affected less the technical actions (successful passes and number of ball losses) from B1 to B4 as compared with 1T and 2T forms. Moreover, the SSG played in 1T form led to reach higher solicitation of the high-intensity actions while players presented more difficulty to perform a correct technical action.
The modification of the number of ball touches authorized per possession affects the soccer player activity from the first to the last bout of SSG, indicating that the determination of this rule has to be precisely planned by the coach according to the objectives of the training.
Anis Chaouachi, Monoem Haddad, Carlo Castagna, Del P. Wong, Fathi Kaouech, Karim Chamari and David G. Behm
The objective of this study was to examine the response and recovery to a single set of maximal, low and high angular velocity isokinetic leg extension-flexion contractions with boys. Sixteen boys (11–14 yrs) performed 10 isokinetic contractions at 60°.s−1 (Isok60) and 300°.s−1 (Isok300). Three contractions at both velocities, blood lactate and ratings of perceived exertion were monitored pretest and at 2, 3, 4, and 5 min of recovery (RI). Participants were tested in a random counterbalanced order for each velocity and recovery period. Only a single contraction velocity (300°.s−1 or 60°.s−1) was tested during recovery at each session to remove confounding influences between the recovery intervals. Recovery results showed no change in quadriceps’ power at 300°.s−1, quadriceps’ power, work and torque at 60°.s−1 and hamstrings’ power and work with 60°.s−1. There was an increase during the 2 min RI in hamstrings’ power, work and torque and quadriceps’
Chaouachi Anis, John B. Leiper, Souissi Nizar, Aaron J. Coutts and Chamari Karim
The month-long diurnal Ramadan fast imposes a major challenge to Islamic athletes. Sporting events are programmed throughout the year, with the result that training and competition are often scheduled during Ramadan. The small numbers of well-controlled studies that have examined the effects of Ramadan on athletic performance suggest that few aspects of physical fitness are negatively affected, and only modest decrements are observed. Whereas subjective feelings of fatigue and other mood indicators are often cited as implying additional stress on the athlete throughout Ramadan, most studies show these measures may not be reflected in decreases in performance. The development and early implementation of sensible eating and sleeping strategies can greatly alleviate the disruptions to training and competitiveness, thus allowing the athlete to perform at a high level while undertaking the religious intermittent fast. Nevertheless, further research is required to understand the mechanisms and energy pathways that allow athletes to maintain their performance capacities during Ramadan, and which factors are responsible for the observed decrements in performance of some individuals.