Asier Los Arcos

Effects of eccentric exercise on optimum length of the knee flexors and extensors during the preseason in professional soccer players

OBJECTIVE To assess the effects of eccentric exercise on optimum lengths of the knee flexors and extensors during the preseason in professional soccer. DESIGN Twenty-eight athletes from a professional Spanish soccer team (Division II) were randomly assigned to an eccentric exercise intervention group (EG) or a control group (CG). Over the four-week period two athletes from the control group suffered RF injuries and two athletes were contracted by other clubs. After these exclusions, both groups (EG, n=13; and CG, n=11) performed regular soccer training during the four-week preseason period. RESULTS After the four weeks, the optimum lengths of the knee flexors were significantly (P<0.05) increased by 2.3 degrees in the CG and by 4.0 degrees in the EG. The change in the EG was significantly (P<0.05) greater than that of the CG. The optimum lengths of the knee extensors were significantly increased only in the EG by 6.5 degrees . Peak torque levels and ratios of quadriceps to hamstring (Q/H ratios) were not significantly altered throughout the study for either group. CONCLUSION Eccentric exercise can increase the optimum lengths of both the knee extensors and knee extensors flexors during the preseason in professional soccer.

Short-Term Training Effects of Vertically and Horizontally Oriented Exercises on Neuromuscular Performance in Professional Soccer Players

PURPOSE The aim of this study was to compare the effects of 2 strength and conditioning programs involving either purely vertically oriented or combining vertically and horizontally oriented exercises on soccer-relevant performance variables (ie, acceleration, jumping ability, peak power, and endurance). METHODS Twenty-two professional male soccer players were randomly assigned to 2 training groups: vertical strength (VS, n = 11) and vertical and horizontal strength (VHS, n = 11). Players trained 2 times per week during all the preseason (5 wk) and 3 weeks of the competitive season. The effect of the training protocols was assessed using double-and single-leg vertical countermovement jumps (CMJ), half-squat peak power (PP), sprint performance over 5 and 15 m, and blood lactate concentration at selected running speeds. RESULTS Both groups obtained significant improvements in PP (P < .05; ES = 0.87 and 0.80 for VS and VHS, respectively) and small practical improvements in 5-m- (P < .05; ES = 0.27 and 0.25 for VS and VHS, respectively) and 15-m-sprint time (P < .05; ES = 0.19 and 0.24 for VS and VHS, respectively). The CMJ performance showed a small improvement (P < .05, ES = 0.34) only in the VHS group. Submaximal aerobic-fitness changes were similar in both groups (P < .05; ES = 1.89 and 0 .71 for VS and VHS, respectively). CONCLUSION This study provided a small amount of practical evidence for the consideration of preseason training protocols that combine exercises for vertical- and horizontal-axis strength development in professional male soccer players. Further studies using more aggressive training protocols involving horizontally oriented conditioning exercises are warranted.

Rating of muscular and respiratory perceived exertion in professional soccer players.

Abstract Los Arcos, A, Yanci, J, Mendiguchia, J, and Gorostiaga, EM. Rating of muscular and respiratory perceived exertion in professional soccer players. J Strength Cond Res 28(11): 3285–3293, 2014—This study investigated, in male professional players: (a) fluctuations in rating of local-muscular (sRPEmus) and central-respiratory (sRPEres) perceived exertion measured after the completion of each training and competitive session, over a 9-week competitive period and (b) the influence of quantitative assessment of different training and competition modes on changes in physical performance. sRPEres, sRPEmus, and heart rate were measured in 21 players in 847 individual training and competitive sessions. Training load was calculated by multiplying sRPEmus or sRPEres by the duration of the training or competition sessions. A test battery (vertical jump, sprint, and endurance running) was performed before and after the studied period. At the end of official matches, average sRPEmus was higher (7.4 ± 0.6; p ⩽ 0.05) than sRPEres (6.4 ± 1.3). Significant negative correlations were observed between the values of total training and competition time (r = −0.62; p < 0.01) or total added sRPEmus (r = −0.59; p ⩽ 0.05), and vertical jump or sprint running velocity changes, respectively. This suggests that sRPEmus should be considered the main fatigue rating during a soccer match. Training and competition volume may have negative effects on the muscle power performance gains of the legs.

Effects of Small-Sided Games vs. Interval Training in Aerobic Fitness and Physical Enjoyment in Young Elite Soccer Players.

The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 ± 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 ± 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment.

Quantification of the perceived training load and its relationship with changes in physical fitness performance in junior soccer players

Abstract The aim of this study was to determine the relationship between perceived respiratory and muscular training load (TL) and changes in physical fitness in elite and non-elite junior soccer players. Twenty-eight elite (n = 14, 17.6 ± 0.6 years, 70.3 ± 4.4 kg, 179.7 ± 5.6 cm) and non-elite (n = 14, 17.5 ± 0.5 years, 71.1 ± 6.5 kg, 178.1 ± 5.6 cm) soccer players belonging to a Spanish first and third division football academies and competing in junior Spanish first division (2012–2013) participated in the study. Countermovement jump (CMJ), CMJ arm swing, 5 and 15 m sprints and the Université de Montreal endurance test were performed in January and 9 weeks later in March. In order to quantify TLs, after each training session and match, players reported their session rating of perceived exertion (sRPE) separately for respiratory (sRPEres) and leg musculature (sRPEmus). Elite players accumulated greater weekly training volume (361 ± 14 vs. 280 ± 48 min; effect sizes (ES) = 5.23 ± 1.74; most likely), and perceived respiratory (1460 ± 184 vs. 1223 ± 260 AU; ES = 1.12 ± 0.79; very likely) and muscular (1548 ± 216 vs. 1318 ± 308 AU; ES = 0.99 ± 0.84; likely) TL than did non-elite players. Training volume, sRPEres-TL and sRPEmus-TL were positively and largely correlated (r = 0.67–0.71) with the changes in aerobic fitness. The present results suggest that a low training volume and TL can impair improvement in aerobic fitness in junior soccer players during the in-season period.

Variability of Objective and Subjective Intensities During Ball Drills in Youth Soccer Players

Abstract Arcos, AL, Martínez-Santos, R, Yanci, J, Martín, J, and Castagna, C. Variability of objective and subjective intensities during ball drills in youth soccer players. J Strength Cond Res 28(3): 752–757, 2014—The aim of this study was to examine the intrasubject (intraclass coefficient correlation [ICC]) and intersubject variability (coefficient of variation [CV]) of soccer ball drills (BD) involving or not opposition in male youth soccer. For this purpose, a collective ball dribbling (DB) exercise and a 7-a-side ball game without coach encouragements were considered. Exercise intensity was assessed as heart rate (HR), training load (TL), and perceived exertion scales. Fourteen U-14 male soccer players (age, 14.79 ± 0.43 years and experience, 6.5 years) of a Spanish First Division club academy participated in the study. Ball drills were examined for variability over 5 successive training sessions in similar field conditions. Results showed that 7-a-side was significantly (p = 0.000) more demanding than DB. Indeed the TL, HRmax, HRmean, overall perceived exertion, and leg muscular perceived exertion (MPE) resulted 141, 8.7, 11, 56, and 72%, higher in 7-a-side than in DB, respectively. In the 7-a-side condition, good intersubject (CV < 10%) and low intrasubject (ICC < 0.7) variability were observed. In the DB condition, CVs were below 10% CV only for HR variables and the ICC values were higher than 0.7 only for MPE. Despite the moderate reproducibility of BD not considering opponents, this condition did not reveal to induce homogeneous physiological responses in young soccer players. Therefore, the use of this kind of drills may be questionable when considered as alternative of moderate intensity generic aerobic training. Despite the higher interaction between players variability in the opposition drills resulted lower, this suggests their use as a specific conditioning exercise.

Effects of horizontal plyometric training volume on soccer players’ performance

ABSTRACT The aim of this study was to examine the dose response effect of strength and conditioning programmes, involving horizontally oriented plyometric exercises, on relevant soccer performance variables. Sixteen soccer players were randomly allocated to two 6-week plyometric training groups (G1 and G2) differing by imposed (twice a week) training volume. Post-training G1 (4.13%; d = 0.43) and G2 (2.45%; d = 0.53) moderately improved their horizontal countermovement jump performance. Significant between-group differences (p < 0.01) in the vertical countermovement jump for force production time (T2) were detected post-training. No significant and practical (p > 0.05, d = trivial or small) post-training improvements in sprint, change of direction ability (CODA) and horizontal arm swing countermovement jump were reported in either group. Horizontal plyometric training was effective in promoting improvement in injury prevention variables. Doubling the volume of a horizontal plyometric training protocol was shown to have no additional effect over functional aspects of soccer players’ performance.

Objective and subjective methods for quantifying training load in wheelchair basketball small-sided games

ABSTRACT The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards’ training load and Stagno’s training impulses (TRIMPMOD) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards’ training load and TRIMPMOD), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P < 0.05; effect size (ES) = 0.66, moderate] and fourth bouts (P < 0.05; ES = 0.64, moderate) than in the first bout, but other measures did not differ. Mean correlations indicated a trivial and small relationship among HR-based and RPE-based training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other.

Influence of match playing time and the length of the between-match microcycle in Spanish professional soccer players’ perceived training load

ABSTRACT Objectives: To analyse the weekly differentiated perceived training load (dRPE-TL) accumulated during the in-season competitive period by professional soccer players depending on: (1) their participation during the previous official match (i.e., ≥45 min; <45 min; 0 min) and (2) the length of the between-match microcycle (8, 7, and 6 days). Methods: Twenty-one Spanish Second Division professional soccer players (age = 26.7 ± 3.1 years; body height = 182.1 ± 4.5 cm; body mass = 76.6 ± 5.6 kg) participated in this study. Weekly dRPE-TL data were collected over a 16-week in-season period during the 2015±2016 season from August to December. After each session, players reported their rating of respiratory (sRPEres) and muscular (sRPEmus) perceived exertions (training load [TL] = sRPE·volume). Results: After the application of the mixed linear model, significant differences (P< 0.01) were only found in the differentiated perceived TL measured each week for the groups specified regarding match participation time. Conclusions: Previous match participation had a substantial effect on players’ accumulated weekly TLs, with greater match participation associated with higher weekly loads regardless of compensatory training strategies. However, the length of the between-match microcycle during 1-match weeks had no effecton players’ accumulated weekly workloads.

Influence of initial performance level and tactical position on the aerobic fitness in soccer players after preseason period

ABSTRACT Objectives: The purpose of this study was to examine the changes in aerobic fitness in young elite Spanish soccer players after the pre-competitive period over 12 seasons depending on the initial performance level and the tactical position. Methods: One hundred and thirty players belonging to the same reserve team of a Spanish La Liga Club participated in this study. Aerobic fitness capacity (the velocity associated with a blood lactate concentration [La]b of 3 mmol l–1 [V3]) was assessed in each season at the start of the preseason (i.e. July), Test 1 (T1), and the start of the competitive period (i.e. September), Test 2 (T2), from 1998 to 2013 season. Results: Taking all seasons together a most likely small improvement (effect size (ES) = 0.52; ±0.09) was found in V3 after preseason, but this varied from trivial to moderate among the seasons. A most likely large improvement was found for the players with lower V3 values in T1 (ES = 1.68; ±0.38) while a likely small enhancement was assigned to the group with higher V3 values (ES = 0.53; ±0.42). Conclusions: Technical staff should be cautious about affirming an improvement in aerobic fitness after preseason.