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Open access

Amine Ghram, James D Young, Rahman Soori and David G Behm

Abstract

The purpose of this study was to compare the effects of unilateral ankle fatigue versus the knee muscles with and without vision on bipedal postural control. Elite judo athletes who competed at the national level with at least 10 years of training experience, were randomised into KNEE (n = 10; 20 ± 2 years) and ANKLE (n = 9; 20 ± 3 years) groups, who performed dynamic isokinetic fatiguing contractions (force decreased to 50% of initial peak torque for three consecutive movements) of the knee flexors and extensors or ankle dorsiflexors and plantar flexors, respectively. Static bipedal postural control (French Posturology Association normative standards) with eyes open and eyes closed was examined before and immediately after the fatiguing task. Postural variables examined were the centre of pressure (CoP) sway in the medio-lateral and antero-posterior directions, total CoP area sway and CoP sway velocity. Although unilateral ankle and knee fatigue adversely affected all bipedal postural measures, with greater disturbances with eyes closed, there were no significant main group or interaction effects between KNEE and ANKLE groups. Unilateral lower limb fatigue adversely affected bipedal balance, with knee extension/flexion fatigue affecting bipedal postural control to a similar extent as unilateral ankle dorsiflexion/plantar flexion fatigue. Hence unilateral fatigue can affect subsequent bilateral performance or also have implications for rehabilitation exercise techniques. Our findings may be limited to judo athletes as other populations were not tested.

Open access

Petros G. Botonis, Argyris G. Toubekis and Theodoros I. Platanou

Abstract

We investigated the effectiveness of a short-duration training period including an overloaded (weeks 1 and 2) and a reduced training load period (weeks 3 and 4) on wellness, swimming performance and a perceived internal training load in eight high-level water-polo players preparing for play-offs. The internal training load was estimated daily using the rating of perceived exertion (RPE) and session duration (session-RPE). Perceived ratings of wellness (fatigue, muscle soreness, sleep quality, stress level and mood) were assessed daily. Swimming performance was evaluated through 400-m and 20-m tests performed before (baseline) and after the end of weeks 2 and 4. In weeks 3 and 4, the internal training load was reduced by 19.0 ± 3.8 and 36.0 ± 4.7%, respectively, compared to week 1 (p = 0.00). Wellness was improved in week 4 (20.4 ± 2.8 AU) compared to week 1 and week 2 by 16.0 ± 2.2 and 17.3 ± 2.9 AU, respectively (p =0.001). At the end of week 4, swimming performance at 400-m and 20-m tests (299.0 ± 10.2 and 10.2 ± 0.3 s) was improved compared to baseline values (301.4 ± 10.9 and 10.4 ± 0.4 s, p < 0.05) and the overloading training period (week 2; 302.9 ± 9.0 and 10.4 ± 0.4 s, p < 0.05). High correlations were observed between the percentage reduction of the internal training load from week 4 to week 1 (-25.3 ± 5.5%) and the respective changes in 20-m time (-2.1 ± 2.2%, r = 0.88, p < 0.01), fatigue perception (39.6 ± 27.1%), muscle soreness (32.5 ± 26.6%), stress levels (25.6 ± 15.1%) and the overall wellness scores (28.6 ± 21.9%, r = 0.74-0.79, p < 0.05). The reduction of the internal training load improved the overall perceived wellness and swimming performance of players. The aforementioned periodization approach may be an effective training strategy in the lead-up to play-off tournaments.

Open access

Konstantina Karatrantou, Vassilis Gerodimos, Eleftheria Katsareli, Nikolaos Manouras, Panagiotis Ioakimidis and Konstantinos Famisis

Abstract

The main objective of this study was to provide an extensive isokinetic profile of the hip joint in youth soccer players, where the literature is limited. Additionally, this study investigated the effect of age on isokinetic peak torque values of hip abductor and adductor muscles and on reciprocal muscle group torque ratios in youth soccer players at different angular velocities (30 vs. 90o/s) and muscle actions (concentric vs. eccentric). Sixty young elite male soccer players were assigned into three equal groups (n = 20): children, young adolescents and older adolescents, and performed five maximal concentric and eccentric hip-abductions and adductions at 30o/s and 90o/s. The results showed a significant increase (p < 0.05) in peak torque values from childhood to adolescence, with the exception of young adolescents vs. older adolescents where no differences were observed. The reciprocal ratios were not affected by age, but improved with an increase in angular velocity with the exception of the CON/ECC ratio that was higher at 30o/s. The data presented in this study provide an extensive isokinetic profile of hip abductor and adductor muscle strength in youth soccer players to assist both coaches and sports medicine professionals in strength monitoring and training.

Open access

Luis Vaz, Sharief Hendricks and Wilbur Kraak

Abstract

The aim of this study was to describe the game related statistics and match analysis of rugby world cups finals from 1987 to 2015. Video recordings of all (n = 8 matches) rugby world cup finals were used for the purpose of this study. Games were analysed using the video analysis software (Sports code V8.9, Sportstec, Australia) and supplementary data were collected from the official reports published by the International Rugby Board and from webpages of Rugby World Cups. Magnitude of differences between the winners and losers was assessed mechanistically. Only 5 tries in total were scored in the last 8 rugby world cup finals. The main two modes of scoring points were penalty kicks and drop goals. Winning teams attempted more penalty kicks, yet seemed to miss more. The number of drop goals was similar between winning and losing teams. These findings highlight the significance of having an on form place-kicker and from a defensive perspective, conceding fewer penalties in kickable positions. Winners of the Rugby World Cup final won more scrums and lost few line-outs, emphasising the importance of winning the set-pieces. Further establishment of these variables and their influence on performance may be used to evaluate team performances and plan more effective tactical approaches to competition

Open access

Ivan Jukic and James J. Tufano

Abstract

Performing traditional sets to failure is fatiguing, but redistributing total rest time to create short frequent sets lessens the fatigue. Since performing traditional sets to failure is not always warranted, we compared the effects of not-to-failure traditional sets and rest redistribution during free-weight back squats in twenty-six strength-trained men (28 ± 5.44 y; 84.6 ± 10.5 kg, 1RM-to-body-mass ratio of 1.82 ± 0.33). They performed three sets of ten repetitions with 4 min inter-set rest (TS) and five sets of six repetitions with 2 min inter-set rest (RR6) at 70% of one repetition maximum. Mean velocity (p > 0.05; d = 0.10 (-0.35, 0.56)) and mean power (p > 0.05; d = 0.19 (-0.27, 0.64)) were not different between protocols, but the rating of perceived exertion (RPE) was less during RR6 (p < 0.05; d = 0.93 (0.44, 1.40)). Also, mean velocity and power output decreased (RR6: 14.10% and 10.95%; TS: 17.10% and 15.85%, respectively) from the first repetition to the last, but the percentage decrease was similar (velocity: p > 0.05; d = 0.16 (0.30, 0.62); power: p > 0.05; d = 0.22 (-0.24, 0.68)). These data suggest that traditional sets and rest redistribution maintain velocity and power output to a similar degree when traditional sets are not performed to failure. However, rest redistribution might be advantageous as RR6 displayed a lower RPE.

Open access

Ronaldo Kobal, Lucas A. Pereira, Katia Kitamura, Anderson C. Paulo, Henrique A. Ramos, Everton C. Carmo, Hamilton Roschel, Valmor Tricoli, Chris Bishop and Irineu Loturco

Abstract

The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly-trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude-based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate-to-high loads may be an effective strategy to improve jump performance in highly-trained subjects. Nevertheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post-activation potentiation protocols.

Open access

Michał Starczewski, Piotr Żmijewski, Katarzyna Witek and Andrzej Klusiewicz

Abstract

The main goal of the study was to evaluate the impact of different roller skiing techniques (classical CT and skating ST) performed under field conditions on physical capacity variables in cross-country skiers. The second purpose was to evaluate the possibility to use the test results conducted under field and laboratory conditions interchangeably to determine training loads. Eight international-level cross-country skiers (4 male, 4 female) with 8.8 ± 1.3 years of skiing experience took part in the study. The athletes performed three graded tests to exhaustion: two under field conditions (roller skiing CT and ST techniques) and one in the laboratory: treadmill running (TR). All tests were conducted within a period of two weeks to compare general and specific physical capacity outcomes. ANOVA demonstrated significant differences in the threshold heart rate (HRAT4) (ST 175.3 ± 10.8 bpm, CT 175.8 ± 10.9 bpm, TR 181.5 ± 11.1 bpm; p = 0.004), maximal oxygen uptake (VO2max) (ST 64.0 ± 4.65 ml/kg/min, CT 61.5 ± 5.09 ml/kg/min, TR 65.9 ± 2.30 ml/kg/min; p = 0.008) and maximal HR (ST 189.3 ± 10.9 bpm, CT 188.9 ± 10.6 bpm, TR 199.5 ± 10.3 bpm; p = 0.002). No significant differences were observed between classical and skating roller skiing techniques for maximal and threshold values except for threshold velocity (CT 13.4 ± 1.11 km/h vs. ST 14.7 ± 1.17 km/h p = 0.002). Maximal velocity was not measured. The main finding of the study is that it is possible to use threshold HR values obtained in roller skiing tests performed using the classical or skating techniques interchangeably to determine roller skiing training loads. The results of the study indicate that there is a need to verify maximal treadmill running exertion variables in specific roller skiing tests.

Open access

Jose Morales, Vicenç Roman, Alexandre Yáñez, Mònica Solana-Tramunt, Juan Álamo and Antón Fíguls

Abstract

This study compares and describes relationships among stress-recovery indices, the heart rate variability index, and the Cooper and Yo-Yo IR1 tests among female soccer players during the last six weeks of the competitive season. Sixteen female soccer players engaged in a pre-test of all of the variables. After having their training monitored for six weeks, a post-test was administered. The results revealed significant (p < 0.05) differences in the specific stress-recovery scales of the RESTQ-sport and in the frequency-domain variables of the HRV, although there were no significant differences in the general stress or general recovery scales. The Yo-Yo IR1 test, the Cooper test scores, and the means of the time-domain HRV variables did not exhibit any significant differences between the pre- and the post-test. The RMSSD variations exhibited very large and large correlations with the performance test and the RESTQ-sport variables, respectively. The variations in the HRV frequency-domain variables exhibited significant moderate and large correlations among the variations of the RESTQ-sport scales. Monitoring athletes at the end of the season may reveal contradictions between some variables. To help with the interpretation of these scales, some external aspects, such as athlete strain and monotony of training, should be considered.

Open access

Marek Konefał, Paweł Chmura, Tomasz Zając, Jan Chmura, Edward Kowalczuk and Marcin Andrzejewski

Abstract

The purpose of the study was to examine how various playing positions affected the number of (and percentage breakdowns for) physical and technical activities of soccer players in the Germany’s Bundesliga. A further objective was to identify and present features distinguishing between the activities of players within the Defender, Midfielder and Forward formations. The study sample comprised 4426 individual match observations of 473 soccer players competing in the Bundesliga during the 2016/2017 domestic season. Data from the Impire AG motion analysis system, and the so-called ”heat maps” it supplies, revealed areas in which players spent most time during a match, with 22 different playing positions on the pitch identified in consequence. Players in the formation comprising Defenders did not differ significantly in relation to the number of accelerations, the number of shots or the percentage of duels won. Furthermore, there were no significant differences among Midfielders in regard to total distance covered, mean running speed, the number of accelerations, the number of duels and the percentage of duels won. Likewise, Forwards did not differ in distances covered at ≥24 km/h, average running speed, the number of sprints, the number of shots, the proportion of on-target passes, the number of duels, or the percentage share of duels won. Irrespective of the formation or position on the pitch, today’s game of soccer also pays great importance to the number of accelerations, as well as the number of duels engaged in, and their effectiveness.

Open access

Gilmar Weber Senna, Jeffrey Michael Willardson, Estevão Scudese, Roberto Simão, Cristiano Queiroz de Oliveira, Jadson de Oliveira Lima, Marzo Edir Da Silva-Grigoletto and Estélio Henrique Martin Dantas

Abstract

The purpose of this study was to examine the acute effects of multi- to single-joint or the reverse exercise order on repetition performance and perceived exertion for the pectoralis major. Fourteen trained men (24.05 ± 4.17 yrs, 78.85 ± 3.51 kg, 175.42 ± 4.01 cm) underwent two different training sequences (SEQ1 and SEQ2). In SEQ1, all subjects performed 5 sets for maximal repetitions, with a 2-min rest interval, of the bench press followed by the machine chest fly with 10 repetitions maximum load. In SEQ2, the same procedures were repeated, but with the reverse order. The t-test did not show any differences (p = 0.140) in total workout repetitions between SEQ1 (62.22 ± 11.00 repetitions) and SEQ2 (55.40 ± 8.51 repetitions). Conversely, the total repetition number for the bench press exercise was significantly greater (p = 0.001) following SEQ1 (34.36 ± 4.68 repetitions) compared to SEQ2 (25.85 ± 6.73 repetitions). In contrast, the total repetition number for the machine chest fly exercise following SEQ2 was significantly greater (p = 0.001) (33.50 + 4.11 repetitions) compared to SEQ1 (27.85 ± 6.52 repetitions). Despite no significant differences found for the rating of perceived exertion (RPE) values between SEQ1 and SEQ2 for the barbell bench press in all sets (p ≥ 0.083), significantly higher RPE values for the machine chest fly were observed over the first three sets following SEQ1 compared to SEQ2 (p < 0.01). In conclusion, the total workout repetitions were not significantly different when performing the traditional multi- to single-joint or the reverse exercise order when training the pectoralis major muscle.