Search

The purpose of this study was to investigate the relationship between maximal sprinting (MSS) and aerobic (MAS) speeds in a cohort of highly-trained young male soccer players with the influence of body mass controlled for using allometric scaling. MSS and MAS were obtained in 14 pre-age at peak height velocity (APHV) players (12.3 ± 0.7 years), 21 circum-APHV players (14.3 ± 0.9 year) and 26 post-APHV players (16.9 ± 0.7 years). The three groups showed similar positive correlations between MSS and MAS (r = 0.73 to 0.52; p < .01). In conclusion, our results suggest that the relationship between MSS and MAS is not affected by maturation. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the current study was to compare the effects of speed/agility (S/A) training with sprint interval training (SIT) on acceleration and repeated sprint ability (RSA) in well-trained male handball players. Methods: In addition to their normal training program, players performed either S/A (n = 7) or SIT (n = 7) training for 4 wk. Speed/agility sessions consisted of 3 to 4 series of 4 to 6 exercises (eg, agility drills, standing start and very short sprints, all of <5 s duration); each repetition and series was interspersed with 30 s and 3 min of passive recovery, respectively. Sprint interval training consisted of 3 to 5 repetitions of 30-s all-out shuttle sprints over 40 m, interspersed with 2 min of passive recovery. Pre- and posttests included a countermovement jump (CMJ), 10-m sprint (10m), RSA test and a graded intermittent aerobic test (30-15 Intermittent Fitness Test, VIFT). Results: S/A training produced a very likely greater improvement in 10-m sprint (+4.6%, 90% CL 1.2 to 7.8), best (+2.7%, 90% CL 0.1 to 5.2) and mean (+2.2%, 90% CL -0.2 to 4.5) RSA times than SIT (all effect sizes [ES] greater than 0.79). In contrast, SIT resulted in an almost certain greater improvement in VIFT compared with S/A (+5.2%, 90% CL 3.5 to 6.9, with ES = -0.83). Conclusion: In well-trained handball players, 4 wk of SIT is likely to have a moderate impact on intermittent endurance capacity only, whereas S/A training is likely to improve acceleration and repeated sprint performance. [ABSTRACT FROM AUTHOR]

This study determined the most effective field method for quantifying fat-free mass (FFM) in elite youth male soccer players compared to dual X-ray absorptiometry (DXA) values and to develop prediction equations for FFM based on anthropometric variables. Forty-one male elite-standard youth soccer players, ages 16.2–18.0 years, undertook FFM assessments including bioelectrical impedance analysis, and different skinfold-based prediction equations. DXA provided a criterion measure of FFM. Correlation coefficients, bias, limits of agreement, and differences were used as validity measures, and regression analyses to develop soccer-specific prediction equations. Slaughter et al (1988), Durnin and Wormersley (1974), and Sarria et al (1998) equations showed the lowest biases, and no significant, standardized, and substantial differences against DXA. The new youth soccer-specific anthropometric equation explained 91% of the DXA-derived FFM variance using three circumferences, eight skinfolds, and one bone breadth. All field methods compared in this study may not be adequate for estimating FFM in elite youth male soccer players, except the equations of Slaughter et al (1988), Durnin and Wormersley (1974), and Sarria et al (1998). We recommend the use of the new soccer-specific equation proposed in this study as a valid alternative to DXA to quantify FFM among elite youth male players. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the association between the MCT1 (monocarboxylate transporter 1) A1470T polymorphism and positional roles in a large cohort of professional football players from five different countries. We compared genotype distributions of the MCT1 A1470T polymorphism between football players (n = 694) and non-athlete controls (n = 781) from Italy, Poland, Lithuania, Ukraine and Malta, and we analyzed the MCT1 genotype distributions with respect to the players' positions in the field (e. g. forwards, midfielders, defenders and goalkeepers). Genomic DNA was extracted from either buccal epithelium or peripheral blood using a standard protocol. In the pooled cohort of Italian, Polish, Lithuanian and Ukrainian football players, forwards (n = 148) were more likely than controls (n = 781) to possess the A allele ( χ² = 7.067, p = 0.029, FDR q value 0.116), with a greater likelihood of having the AA genotype compared with the TT genotype (OR = 1.97; C.I. = 1.07-3.64; p = 0.021, FDR q value 0.086). The MCT1 AA genotype was significantly more frequent in forwards then in controls. Further studies are needed to confirm these findings in other professional football player cohorts. [ABSTRACT FROM AUTHOR]

This study investigated the effects of successive matches on match-running in elite under-23 soccer players during an international tournament. Match-running data was collected using a semi-automated multi-camera tracking system during an international under-23 tournament from all participating outfield players. Players who played 100% of all group stage matches were included (3 matches separated by 72 h,n = 44). Differences in match-running performance between matches were identified using a generalised linear mixed model. There were no clear effects for total, walking, jogging, running, high-speed running and sprinting distance between matches 1 and 3 (effect size (ES); −0.32 to 0.05). Positional analysis found that sprint distance was largely maintained from matches 1 to 3 across all positions. Attackers had a moderate decrease in total, jogging and running distance between matches 1 and 3 (ES; −0.72 to −0.66). Classifying players as increasers or decreasers in match-running revealed that match-running changes are susceptible to individual differences. Sprint performance appears to be maintained over successive matches regardless of playing position. However, reductions in other match-running categories vary between positions. Changes in match-running over successive matches affect individuals differently; thus, players should be monitored on an individual basis. [ABSTRACT FROM PUBLISHER]

Delgado-Bordonau, J.L., Domenech-Monforte, C., Guzmán, J.F. & Mendez-Villanueva, A. (2013). Offensive and defensive team performance: relation to successful and unsuccessful participation in the 2010 Soccer World Cup. J. Hum. Sport Exerc., 8(4), pp.894-904. The present study was conducted to analyze the impact of selected offensive and defensive performance indicators in relation to teams' success in the 2010 soccer World Cup. The sample used corresponded to 54 matches played in both the group and knockout stage. The game-related statistics gathered were: total shots, shots on goal, shots off goal, % of shots on goal from total shots, % of shots off goal from total shots, offensive and defensive effectiveness 1 (goals /total shots), and offensive and defensive effectiveness 2 (goals/shots on goal). In addition, the first's goal influence in the match's outcome (for the team scoring the goal: win, draw, lose) was also investigated. The results showed that, during the group stage, successful teams had better values (P <0.05) in all offensive and defensive performance indicators, with the exception of shots off goal for and shots off goal against, respectively, than unsuccessful teams. In the knockout stage, successful teams were able to maintain the same offensive performance that in the group stage while most defensive performance indicators, with the exception of shots off goal against (P=0.80), tended (P<0.2) to worsen. During the group stage, the team scoring the first goal had 66.7% of victories, 4.2% of defeats and 29.2% of draws (P<0.001). In the knockout stage, the first goal effect had a stronger influence in game's outcome than in the group stage (P<0.01) since in 81.3% of the cases the team scoring first won the match, versus 6.3% of defeats and 12.5% of draws. Thus, offensive variables related to shots on goal and goal effectiveness appear to be better indicators of team's success in the last World Cup than defensive variables. This information has directly implications for coaches, providing relevant feedback to plan finishing (goal scoring) practices. [ABSTRACT FROM AUTHOR]

In this study we assessed the effect of acute hypoxia on post-exercise parasympathetic reactivation inferred from heart rate (HR) recovery (HRR) and HR variability (HRV) indices. Ten healthy males participated in this study. Following 10min of seated rest, participants performed 5min of submaximal running at the speed associated with the first ventilatory threshold (sub) followed by a 20-s all-out supramaximal sprint (supra). Both sub and supra runs were immediately followed by 15 min of seated passive recovery. The resting and exercise sequence were performed in both normoxia (N) and normobaric hypoxia (H; FiO2 = 15.4%). HRR indices (e.g., heart beats recovered in the first minute after exercise cessation, HRR60s) and vagal-related HRV indices [i.e., natural logarithm of the square root of the mean of the sum of the squared differences between adjacent normal R-R intervals (Ln rMSSD)] were calculated for both conditions. Difference in the changes between N and H for all HR-derived indices were also calculated for both sub and supra. HRR60s was greater in N compared with H following sub only (60 ±14 vs. 52 ± 19 beats min-1, P = 0.016). Ln rMSSD was greater in N compared with H (post sub: 3.60 ±0.45 vs. 3.28 ± 0.44 ms in N and H, respectively, and post supra: 2.66 ±0.54 vs. 2.65 ± 0.63 ms, main condition effect P = 0.02). When comparing the difference in the changes, hypoxia decreased HRR60s (-14.3% ± 17.2 vs. 5.2% ± 19.3; following sub and supra, respectively; P = 0.03) and Ln rMSSD (-8.6% ±7.0 vs. 2.0% ± 13.3, following sub and supra, respectively; P = 0.08, Cohen's effect size = 0.62) more following sub than supra. While hypoxia may delay parasympathetic reactivation following submaximal exercise, its effect is not apparent following supramaximal exercise. This may suggest that the effect of blood O2 partial pressure on parasympathetic reactivation is limited under heightened sympathetic activation. [ABSTRACT FROM AUTHOR]

The aim of the study was to examine whether differences in playing level influence the activity profile and physiological demands of advanced and recreational veteran male tennis players during an hour of tennis match-play. Ten advanced (International Tennis Number (ITN) 3-5, 45.3±5.1 years) and 10 recreational (ITN 7-9, 44.8±4.7 years) veteran male tennis players participated in a study conducted in Barcelona (Spain). Physiological demands (i.e., Oxygen uptake (VO2) and heart rate (HR)) during an incremental laboratory test, an hour simulated match play, and a half an hour simulated match play using a portable gas analyser, did not differ significantly (p > 0.05) between advanced and recreational players. The advanced players covered significantly more meters than the recreational players during their one hour tennis match. The results obtained indicate that tennis match play satisfies, independently of the playing ability of the players, the ACSM recommendations for quantity and quality of exercise for the development and maintenance of cardiovascular fitness in healthy adults and seems to be a viable and highly popular mode of healthy activity. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the match activity and physiological demands of women's tennis during a 3-day clay-court tennis tournament. The activity profile of eight players was determined by filming each competitive match with video cameras. Metabolic-perceptual measurements-blood samples and individual ratings of perceived exertion (RPE)-were taken while the players were sitting during permitted changeover breaks in play. The activity profile of the players was as follows: strokes per rally, 2.5 ± 1.6; rally duration, 7.2 ± 5.2 s; rest time between rallies, 15.5 ± 7.3 s; effective playing time, 21.6 ± 6.1%; work-to-rest ratio, 1:2.1. Blood lactate concentration [2.2 ± 0.9 mmol · l-1 (n = 50) vs. 2.2 ± 0.7 mmol · l-1 (n = 48)] and RPE values [12.2 ± 2.4 (n = 57) vs. 12 ± 2.3 (n = 57)] were not significantly different (P = 0.65-0.78) between service and return games. The results highlight the importance of taking these factors (i.e. activity patterns and physiological profile) into account when planning training strategies for competitive females players. As such, tennis training regimes should be adapted to the specific demands imposed by match-play in female players on a clay-court surface. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article related to the importance of afferent feedback as a determinant of endurance exercise performance.

The aims of the study were to test: 1) whether the relative age effect (RAE) was prevalent in young (U12-U18) German male tennis players; 2) the potential influence of age and/or skill level on RAE and 3) whether maturity, anthropometric and fitness measures vary according to birth date distribution in elite youth tennis players. For the present study the following male populations were analysed: Overall German population (n = 3.216.811), all players affiliated to the German Tennis Federation (DTB) (n = 120.851), players with DTB official ranking (n = 7165), regional (n = 381) and national (n = 57) squads (11-17 years old), as well as the top 50 German senior players were analyzed. RAEs were more prevalent at higher competitive levels with more players born in the first quarter of the year compared with the reference population for ranked (29.6%), regional (38.1%) and national (42.1%) players. No systematic differences were found in any of the maturity, anthropometric and fitness characteristics of the regional squad players born across different quarters. RAEs are present in the DTB competitive system and it was more pronounced at higher competitive levels. Compared with early born, late born players who were selected into elite squads did not differ in maturation, anthropometric and fitness characteristics. [ABSTRACT FROM AUTHOR]