Effects of Passive and Active Rest on Physiological Responses and Time Motion Characteristics in Different Small Sided Soccer Games

The variability of physical enjoyment, physiological responses, and technical-tactical performance according to the bout duration of small-sided games: a comparative study between female and male soccer players

BACKGROUND

This study aimed to compare various factors, namely perceived enjoyment (PE), percentage of peak heart rate (%HRpeak), blood lactate (La), rating of perceived exertion (RPE), and technical-tactical performance among soccer players across different bout durations (CB: continuous bout, MIB: medium intermittent bouts, and SIB: short intermittent bouts) and between male and female players during four-a-side (4vs4) small-sided games (SSGs) including goalkeepers.

METHODS

sixteen female soccer players (age: 20.1 ± 0.5 years old) and sixteen professional male adults (age: 20.7 ± 0.7 years old) participated in the study. SSGs (4vs4) were performed in a CB: (1 × 12 min), and in an interval format: MIB: (2 × 6 min), and SIB: (3 × 4 min) with 2 min of passive recovery. PE was collected after each SSGs. The players' heart rate (HR) was continuously measured, whereas ratings of perceived exertion (RPE) and, blood lactate concentration ([La]) were determined at the end of each SSGs. Technical-tactical performance were analyzed during each session of SSGs. Pitch dimensions were (length x width) (25 × 32 m), and relative space per players was 100 m2.

RESULTS

For female soccer players, medium intermittent bouts (MIB) elicited significantly higher perceived enjoyment (PE) compared to continuous bouts (CB) (p < 0.001) and short intermittent bouts (SIB) (p < 0.01). Conversely, for male soccer players, CB resulted in higher PE compared to MIB (p < 0.001) and SIB (p < 0.001). During CB and MIB, peak heart rate (PeakHR) and percentage of peak heart rate (%HRpeak) were significantly higher in female players compared to SIB (PeakHR: CB: p < 0.001; PeakHR: MIB: p < 0.01; %HRpeak: CB: p < 0.001; %HRpeak: MIB: p < 0.01). Blood lactate (La) and rating of perceived exertion (RPE) were significantly greater in CB compared to MIB (La: p < 0.001; RPE: p < 0.01) and SIB (La: p < 0.001; RPE: p < 0.001) for female players only. For male players, CB resulted in significantly higher PeakHR, %HRpeak, La, and RPE compared to MIB (peak HR: p < 0.01, dunb = 1.35; %HR: p < 0.01; La: p < 0.01; RPE: p < 0.01) and SIB (peak HR: p < 0,01; %HR: p < 0.01; RPE: md = 0.87, p < 0.05). Regarding technical-tactical performance, in female players, the % of successful passes, successful tackles, and successful duels were higher during SIB compared to CB (p < 0.01; p < 0.001; p < 0.001) and MIB compared to CB (p < 0.01; p < 0.001; p < 0.001), while ball loss was lower during SIB compared to CB (p < 0.001) and MIB compared to CB (p < 0.001). In male players, % of successful passes and tackles were higher during CB compared to MIB (p < 0.001 and p < 0.05) and SIB (p < 0.001 and p < 0.05), while CB had a lower % of ball loss compared to MIB (p < 0.01) and SIB (p < 0.001). There was no significant difference in the % of successful duels between the bouts for either gender.

CONCLUSION

This study showed a difference in physical enjoyment between male and female soccer players depending on the bout duration of SSGs. For that, trainers should consider intermittent bouts for female soccer players and continuous bouts for male soccer players when designing SSGs-based training in order to significantly improve PE, training load, and technical-tactical performance.

The effects of high-intensity interval training at the anaerobic and psychomotor fatigue thresholds on physiological parameters in young soccer players: a prospective study

This study aimed to investigate the effects of a 4-week specific high-intensity interval training (HIIT) program performed between the anaerobic threshold (ANT) and the psychomotor fatigue threshold (PFT) on physiological parameters in 14 professional soccer players at the under-17 level. The first and second stages of the research protocol included a treadmill running exercise with increasing load and six 3-min four-versus-four games of soccer with a 3-min break between games. Players then participated in a training microcycle involving three specific HIIT exercises twice per week for 4 weeks, after which they repeated stages one and two, followed by an assessment of changes. The measurement of lactate (LA) determined ANT, whereas the choice reaction time (CRT) indicated PFT among other selected physiological parameters. The repeated-measure analysis of variance (ANOVA) compared mean values for the examined variables using Bonferroni post hoc test. It demonstrated significantly increased maximal oxygen consumption (VO2 max) from 45.9 ± 3.0 to 48.7 ± 2.6 at the ANT and from 49.1 ± 3.4 to 52.0 ± 3.6 on the PFT after 4 weeks of training. A significant increase in the running speed (RS) at both thresholds and heart rate (HR) at the ANT (p ≤ 0.05) was also recorded. Moreover, the players exceeded their intensity of effort during ANT while playing four-versus-four soccer matches, but they did not reach intensity during PFT. In conclusion, the findings of the study demonstrated that both thresholds shifted toward higher loads and the proposed specific HIIT effectively increased the exercise capacity of soccer players.

The Influence of Pitch Dimensions during Small-Sided Games to Reach Match Physical and Physiological Demands on the Youth Soccer Players

The aims of this study were to (i) analyze the physical and physiological responses of four matches competition and (ii) to investigate the relationships among three different pitch dimensions of small-sided game (SSG) on the youth soccer players. Fifteen male U19 soccer players (age 17.3 ± 0.5 years, height 175.7 ± 5.6 cm, weight 68.5 ± 8.6 kg, playing experience 7.8 ± 1.4 years) were randomly assigned to three play areas: small (50 m²), medium (SSG-m, 150 m²) and large (SSG-l, 250 m²) area per player including goalkeeper. During the 4-week intervention, both groups performed three sets of 8 min with a passive rest period of 5 min between games. Differences in time-motion characteristics of players were measured with the Global Positioning System and assessed using a repeated measures ANOVA to compare the three game conditions and the magnitude-based inference to evaluate the pairwise comparison effects. The results showed that only the variables distance covered between 7.0-12.9 km·h^-1 was not statistically significantly different among game conditions (p < 0.05; η = 0.21; small) and physiological response (i.e., hear rate of playing time spent 85-89% HR_max) also showed differences (p < 0.05; η = 0.25; small). The responses in SSG-m and SSG-l established them ass the format sizes ideal for replicating the physical responses during match competition. These findings could provide relevant information for coaches for use adequate pitch size (areas of 150 m² and 250 m²) to reach the match-play scenarios found in match competition.

The ability of energy recovery in professional soccer players is increased by individualized low-intensity exercise

The aim of this study was to investigate whether individualized low-intensity exercise (ILIE) within the recovery domain before lactate threshold 1 (LT 1) improves energetic recovery and general endurance capacity in professional soccer players. Twenty-four professional soccer players (age: 24.53 ± 4.85 years, height: 180 ± 6.30 cm, body mass: 75.86 ± 8.01 kg, body fat: 12.19 ± 2.69%) participated in the study (n = 24). The 1-h ILIE intervention involved 27 jogging sessions spanning nine weeks and jogging speed corresponding to 72% of LT 1 (7.15 ± 0.95 km∙h⁻¹). Pre-ILIE and post-ILIE LT testing variables measured within 9 weeks included blood lactate concentrations (La⁻) and heart rate (HR) at specific exercise intensities during ILIE LT test. The jogging/running speeds (S), delta (Δ) S, HR, and ΔHR were measured at 1.5, 2.0, 3.0, and 4.0 mmol∙L⁻¹ La⁻, respectively. Values of La⁻ and HR at the same exercise intensities (5.4–16.2 km∙h⁻¹) in the post-ILIE LT test compared with pre-ILIE LT test were significantly decreased (P < 0.05 and P < 0.01, respectively). Furthermore, S at all specific La⁻ levels (1.5, 2.0, 3.0, and 4.0) were significantly increased, while HR at 2.0, 3.0, and 4.0 La⁻ decreased significantly (P < 0.05 and P < 0.01, respectively). Low to moderate positive correlations were observed between ΔS and ΔHR at 1.5 and 2.0 La⁻ (r = 0.52 and r = 0.40, respectively). The nine-week ILIE improved energy recovery and general endurance of professional soccer players. This relates to repeated high-intensity intermittent sprints during the 90-min soccer game.

The Influence of Small-Sided Football Games with Numerical Variability in External Training Load

Small-sided games (SSGs) are a motivational strategy and effective training method to develop skills and physical fitness at optimal intensity. This study investigates the influence of variability in the number of players on the physiological response using SSGs. The sample was composed of 10 field players with an average age of 15.9 ± 0.50 years old. Three sessions were held on 3 different days to collect information. The 10 min SSG exercise with temporal numerical variability was repeated twice on each day. The numerical ratio of players involved changed every 2 min without disrupting the practice. In a game space with 35 × 25 m, the exercise always started in a situation of 3 vs. 3. External training load metrics (i.e., physical activity counts, activity intensity, and energy expenditure) were assessed using Actigraph WGT3X accelerometers. The 3 vs. 3 format game had higher physical activity counts (i.e., higher vector magnitude) and requested more time spent in very vigorous physical activity intensity. Consequently, the 3 vs. 3 format in young football players had higher energy expenditure (i.e., a higher METs) than that in the other studied game formats. This study confirms the influence of SSGs with numerical variability in external training load.

Combining small-sided soccer games and running-based methods: A systematic review

Small-sided games (SSGs) are often used in soccer to produce acute physiological and physical responses, while a tactical/technical stimulus is also employed. However, due to some limitations of SSGs, researchers have been testing this method combined with running-based training methods. This systematic review was conducted to assess the effects of combined SSG and running-based methods on soccer players' acute responses and adaptations after training interventions. A systematic review of Web of Science, PubMed, Cochrane Library, Scopus, and SPORTDiscus databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The database search initially identified 782 titles. From those, five articles were deemed eligible for the systematic review. The five included studies presented data from training load, reporting inconsistent greater values in combined SSG and running-based methods when compared to SSG-only formats. Considering the adaptations, studies comparing combined SSG and running-based methods with SSG-only methods revealed inconsistent differences in terms of the effects on aerobic performance and sprinting. Combining SSG and running-based methods can increase the acute mechanical load and high-intense running stimuli in players when compared to interventions that use only SSGs. However, the adaptations promoted by both methods are similar, and the differences are unclear. The order of combination (SSG and running-based method) does not seem to impact players' adaptations; however, the frequency of sessions did have a meaningful impact.

In-season monotony, strain and acute/chronic workload of perceived exertion, global positioning system running based variables between player positions of a top elite soccer team

Background

The interpretation of the load variations across a period seems important to control the weekly progression or variation of the load, or to identify within- micro and mesocycle variations. Thus, the aim of this study was to describe the in-season variations of training monotony, training strain, and acute: chronic workload ratio (ACWR) through session rating of perceived exertion (s-RPE), total distance and high-speed running (HSR) according to playing positions in an elite soccer team.

Methods

Seventeen professional players from an European First League team participated in this study. They were divided four central defenders (CD), three wide defenders (WD), four central midfielders (CM), three wide midfielders (WM) and three strikers (ST). The players were monitored daily over a 41-week period of competition where 52 matches occurred during the 2015–2016 in-season. Through the collection of s-RPE, total distance and HSR, training monotony, training strain and ACWR were calculated for each measure, respectively. Data were analysed across ten mesocycles (M: 1–10).

Results

The main results showed significant differences (p < 0.05) for TMs-RPE between CD vs. ST (moderate effect) in M2; between CD vs. CM (moderate effect) for TS of s-RPE; between CD vs. ST moderate effect) in M6 for ACWR of s-RPE. In addition, there was significant difference between CM vs. ST (moderate effect) in M2 for TS of TD; between WD vs. ST (moderate effect) in M3 for ACWR of TD. Moreover, there were significant differences for TM of HSR between CD vs. WD (very large effect); CD vs. WD (moderate effect) in M4 for TS of HSR.

Conclusions

The present study presents new insights to coaches and technical staff about the variation profiling of TM, TS, and ACWR calculated with internal and external load measures, between player positions during 10 mesocycles.

Influence of Different Small-Sided Game Formats on Physical and Physiological Demands and Physical Performance in Young Soccer Players

ABSTRACT

Castillo, D, Rodríguez-Fernández, A, Nakamura, FY, Sanchez-Sanchez, J, Ramirez-Campillo, R, Yanci, J, Zubillaga, A, and Raya-González, J. Influence of different small-sided game formats on physical and physiological demands and physical performance in young soccer players. J Strength Cond Res 35(8): 2287-2293, 2021-The aim of this study was to quantify the acute impact of bout duration and individual interaction space on physical and physiological demands and on physical performance. Ten young male soccer players (age: 14.8 ± 0.6 years) from the same team playing in the National U-16 Division participated. Physical (total distance [TD]; distance covered at different speeds; and maximum velocity [Velmax]) and physiological (peak [HRpeak] and mean [HRmean] heart rate) parameters were collected for every bout during each small-sided game (SSG) format. Moreover, the effects of SSGs on horizontal jump (HJ) and 30-m sprint performances were evaluated. The SSG formats were composed of 6 players a side (including goalkeepers) and included 4 repetitions of 6 minutes in a space of 100 m2 (SSG1) or 200 m2 (SSG2) and 6 repetitions of 4 minutes in 100 m2 (SSG3) or 200 m2 (SSG4). The TD, the distance covered at different speeds, and Velmax were greater (p < 0.01, effect size [ES] = 1.25-5.95, large) in SSG2 and SSG4 than SSG1 and SSG3, respectively. Furthermore, the HRmean and HRpeak were lower (p < 0.05, ES = 1.53-2.23, large) during SSG3 than other SSGs. In addition, while a significant (p < 0.05, ES = 0.70-2.04, moderate to large) increase in SPR30 time in SSG1 and SSG3 was observed, HJ performance was not affected (p > 0.05, ES = 0.03-0.54, trivial to moderate) by any SSG format. These findings suggest increasing pitch size to induce greater physical demands and to use SSGs with smaller pitch size, and independently of the bout duration, to induce neuromuscular fatigue.

Intra- and Inter-week Variations of Well-Being Across a Season: A Cohort Study in Elite Youth Male Soccer Players

This study describes the weekly variations of well-being ratings relative to fatigue (wFatigue), stress (wStress), delayed-onset muscle soreness (wDOMS), sleep quality (wSleep), and Hooper questionnaire (wHQ) throughout the season. In addition, the well-being variables for the playing position in different moments of the season were discussed. Twenty-one elite young soccer players U17 took part in this study. From the beginning of the pre-season, well-being status was monitored daily by the HQ method throughout 36 weeks, including four periods: (1) pre-season, (2) early-season, (3) mid-season, and (4) end-season. Players trained at least 3 times per week throughout the season. The main outcome was that, in weeks 33 and 28, the highest [wFatigue: 15.85 ± 3.38 arbitrary units (AU); wHQ: 48.86 ± 9.23 AU] and the lowest (wFatigue: 5.38 ± 1.88 AU; wHQ: 20.43 ± 5.49 AU) wFatigue and wHQ occurred, respectively, although the lowest level of wDOMS happened in week 28 (4.86 ± 2.15 AU), while the highest wDOMS was observed in week 5 (14.65 ± 4.16 AU). The highest wSleep (13.00 ± 2.12 AU) and wStress (11.65 ± 2.92 AU) were observed in weeks 8 and 34, respectively, while the lowest wSleep (5.81 ± 2.29 AU) and wStress (3.76 ± 0.94 AU) were marked in week 29 coincidentally. In the HQ between every weekday, except recovery day, and the day of the match (MD), considerable highest HQ was only revealed in 2 days after MD in contrast to overall team comparison. In the present study, we observed that the well-being changes between different phases of the season as well as between weeks and days of the week with the MD are significant. These results provide a great point of view for coaches and practitioners about well-being variations over a season in elite youth soccer level. As a result, coaches will be more aware about non-functional overreaching and taking measures to prevent it.

Recovery Kinetics Following Small-Sided Games in Competitive Soccer Players: Does Player Density Size Matter?

PURPOSE

To examine the recovery kinetics of exercise-induced muscle damage (EIMD), neuromuscular fatigue, and performance following small-sided games (SSGs) of different densities in soccer.

METHODS

Ten male players randomly completed 3 trials: a control trial (no SSGs), 4v4 SSGs (62.5 m2/player), and 8v8 SSGs (284.4 m2/player). External and internal load were monitored using GPS technology, heart-rate monitors, and rating of perceived exertion. Delayed-onset muscle soreness (DOMS), creatine kinase (CK), isokinetic strength, countermovement jump (CMJ), and sprint were determined at baseline, as well as at 24, 48, and 72 hours post-SSGs. Neuromuscular fatigue was assessed at baseline and at 1, 2, and 3 hours post-SSGs.

RESULTS

DOMS increased (P < .05) in 4v4 for 72 hours and in 8v8 for 24 hours with that of knee flexors being more pronounced than that of extensors. CK increased (P < .05) in 4v4 for 72 hours and in 8v8 for 24 hours. Neuromuscular fatigue increased (P < .05) in 4v4 for 2 hours and in 8v8 for 3 hours. Strength declined (P < .05) in 4v4 for 48 hours and in 8v8 for 72 hours. CMJ decreased (P < .05) in 4v4 for 24 hours and in 8v8 for 48 hours. Sprint decreased (P < .05) for 48 hours in 4v4 and for 72 hours in 8v8.

CONCLUSIONS

SSGs are associated with a prolonged rise of EIMD and induce short-term neuromuscular fatigue and slow recovery kinetics of strength, jump, and sprinting performance. The time for complete recovery is longer for SSGs of lower density.

Relationships Between Aerobic Performance, Hemoglobin Levels, and Training Load During Small-Sided Games: A Study in Professional Soccer Players

The purposes of this study were (1) to analyze between-session variations of external and internal load measures during small-sided games (SSGs) and (2) to test the relationships between the maximum speed reached (VIFT) during the last stage of the 30-15 Intermittent Fitness Test, hemoglobin levels, and training load measures during SSG intervals among professional soccer players. Sixteen professional soccer players (mean ± SD; age 27.2 ± 3.4 years, height 174.2 ± 3.6 cm, body mass 69.1 ± 6.4 kg, and body fat 10.4 ± 4.1%) participated in this study. Hemoglobin and aerobic performance were first tested, and then a 3-week SSG program was applied using a 3 vs. 3 format. During those 3 weeks, internal and external load of entire sessions were also monitored for all training sessions. Trivial-to-small, standardized differences were observed between sessions for external and internal measures during SSGs. Total distance (TD) and mechanical work (MW) were the only variables that indicated small changes. Large-to-very-large relationships were found between VIFT and external loads: TD (r range: 0.69; 0.87), high-intensity running (HIR; r range: 0.66; 0.75), and MW (r range: 0.56; 0.68). Moderate-to-large negative relationships were found between hemoglobin levels and internal loads: Edwards' TRIMP (r range: -0.36; -0.63), %HRmax (r range: -0.50; -0.61), and red zone (r range: -0.50; -0.61). VIFT had unclear relationships with overall internal loads, while hemoglobin levels presented unclear relationships with overall external loads. In conclusion, no meaningful changes were found between sessions considering the format of play used. Additionally, the detected relationships indicate that VIFT and hemoglobin levels are good indicators of the performance capacity and physiological profile of players during SSGs. Also, the use of SSGs protocols as a monitoring complement of the 30-15IFT is suggested.

Relationships between Training Loads and Selected Blood Parameters in Professional Soccer Players during a 12-Day Sports Camp

The main purpose of this study is to assess the relations between training loads and selected blood parameters in professional soccer players during a preseason sports camp. Fifteen professional soccer players (age: 24.3 ± 5.25 year; height: 182.6 ± 6.75 cm; weight: 76.4 ± 6.72 kg) participated in the 12-day training camp. All the training sessions and friendly games were accurately analyzed with a GPS system. Blood samples were taken from the players and analyzed before the camp (PRE), in the middle (MID), and one day after the camp (POST). Mean total distance covered by the players during the camp was 85,205 ± 2685 m, high-intensity running 12,454 ± 1873 m, and sprinting 639 ± 219 m. The highest aspartate transaminase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), and C-reactive protein (CRP) values were observed after six days of the camp. The application of intensive training during a 12-day sports camp can be associated with chronic muscle pain with high activity of some blood enzymes (CK, AST) and a high concentration of myoglobin (Mb). During training camps longer than 10 days, it would be necessary to apply, every second or third day, one day of rest, and the training load should not exceed two units every day.

Acute effects of small-sided games combined with running drills on internal and external loads in young soccer players

The purpose of this study was to compare the effects of regular small-sided games (SSGreg) and SSGs combined with running drills (SSGcom) on players' internal and external loads. Eighteen young male soccer players (average age: 18.2 ± 0.5 years) participated in 3 vs. 3 and 4 vs. 4 games, under both SSGreg and SSGcom conditions. SSGreg bouts were played for 4 minutes without additional running drills, while SSGcom bouts consisted of 3 min 30 s SSG and 15 s running before and after the bout, making the duration of each bout 4 minutes. During all SSGs, measurements of heart rate (HR) responses as well as distances covered in four different speed zones - walking (WLK), low-intensity (LIR), moderate-intensity (MIR) and high-intensity running (HIR) - were recorded. Technical characteristics were monitored during the SSGs, and the rating of perceived exertion (RPE) and blood lactate (La-) responses were determined at the end of each SSG condition. Compared to the SSGreg in both 3 vs. 3 and 4 vs. 4 formats, the SSGcom condition resulted in higher La- and RPE responses (p < 0.05), greater distance covered at MIR and HIR speeds and greater total distance (p < 0.05). The results of this study show that replacing 30 s within the 4-min bouts of SSGs (both 3- and 4-a-side) by 2 x 15 s of running drills is effective in increasing internal (La- and RPE) and external loads (MIR and HIR) without a significant decrease in total passes and successful passes in young soccer players.

Adapted recreational football small-sided games improve cardiac capacity, body composition and muscular fitness in patients with type 2 diabetes

BACKGROUND

The usefulness of adapted small-sided games (SSGs) in improving cardiac function in subjects with T2DM is still debated. Here we evaluated the effects of 18 weeks indoor muscular activation training (6 weeks; IMA) followed by adapted SSGs football training (12 weeks) on cardiac function, muscular fitness, body composition and adiponectin expression in sedentary T2DM volunteers.

METHODS

Six T2DM patients underwent IMA protocol of 6 weeks, twice a week followed by 12 weeks SSGs (5-a-side, once a week) training. Glucose, lipid profile and serum homocysteine concentration, body composition (BC), bone mineral density (DEXA), were determined at baseline and after 18 weeks (IMA+SSGs). VO<inf>2max</inf> and muscular fitness were recorded at baseline and after IMA (6 weeks) and SSGs (12 weeks), respectively.

RESULTS

No significant differences were found for VO<inf>2max</inf> and muscular fitness after 6weeks of IMA. After 18 weeks (6 weeks IMA + 12 weeks SSGs) of training, significant improvements were found in the following parameters: work capacity, VO<inf>2peak</inf>, Ventilation (VE<inf>peak</inf>), breathing reserve consumption and oxygen uptake efficiency slope (P<0.05); leg fitness (P<0.05), BC (P<0.05), vertebral column T-score (P<0.01) and adiponectin (total and high-molecular-weight; P<0.05). Compared to baseline, a reduction in serum homocysteine occurred after 18 weeks of training (P<0.05).

CONCLUSIONS

We evidenced that weekly adapted SSGs friendly football matches for 12 weeks improve cardiorespiratory capacity and the expression of independent markers associated with cardiovascular risk in T2DM patients, suggesting an overall reduced CVD-risk in these patients. These preliminary data encourage us to test the efficacy of this type of exercise in a larger population.

Running-based high-intensity interval training vs. small-sided game training programs: effects on the physical performance, psychophysiological responses and technical skills in young soccer players

This study aimed to compare the effects of 5-week running-based high-intensity interval training (HIIT) vs. small-sided game training (SSG) on the physical performance, psychophysiological responses and technical skills in young soccer players. Twenty young male soccer players (age: 14.2±0.5 years, height: 161.8±7.9 cm) participated in this study and were assigned to two groups: the HIIT group (n=10) and SSG group (n=10). Both groups trained twice per week with a similar total training duration. The SSG consisted of two 5–9 minutes of 2-a-side with 2-minute passive rest periods, whereas the HIIT consisted of 12–20 minutes of continuous runs at intensities (90 to 95%) related to the velocity obtained in the 30–15 intermittent fitness test. Before and after the 5-week training periods the following tests were completed: maximum oxygen consumption (VO_2max) from the Yo-Yo Intermittent Recovery Test level 1 (YYIRTL-1), 10–30-m sprint test, countermovement jump [CMJ], squat jump [SJ], and drop jump [DJ]), 1000-m run test, zigzag agility, repeated sprint ability, 30–15 intermittent fitness test and speed dribbling ability test. Our results revealed meaningful improvements in YYIRTL-1 performance (SSG: +12.8%, standardized effect size [d]=-1.46; HIIT: +16.4%, d=3.27 and VO_2max (SSG: +3.3%, d=-1.48; HIIT: +4.3%, d=2.61). There was a meaningful greater improvement in agility and technical test performances following the SSG training compared with the HIIT (p ≤ 0.05, d=ranging from 0.92 to 1.99). By contrast, the HIIT group showed meaningfully higher performance responses in terms of the 1000-m running time and repeated sprint test ability (p ≤ 0.05, d=ranging from 0.90 to 2.06). These results confirmed that SSG training might be a more effective training regime to improve technical ability and agility with greater enjoyment, whereas HIIT might be more suitable for speed-based conditioning in young soccer players.

A systematic review on small-sided games in football players: Acute and chronic adaptations

Small-sided games (SSG) are played on a small pitch, often using modified rules and involving a smaller number of players. This article aimed to critically analyse the literature to determine how small-sided games affect the performance of football players in the short- and long term. Electronic databases were searched for literature dating from January 2000 to July 2018. The methodological quality of the studies was evaluated using the modified Downs and Black Quality Index (cross-sectional studies) and the Physiotherapy Evidence Database (PEDro) scale (intervention studies). Fifty-three studies, 44 cross-sectional and 9 intervention studies, met the inclusionary criteria for review. Most of the cross-sectional studies focused on describing the differences between SSG protocols, whereas 4 studies focused on making a comparison between "interval" and "continuous" SSG training regimes. On the other hand, intervention studies focused on making a comparison between SSG-based protocols and high-intensity intermittent training (HIIT)-based running protocols, in addition to determine the effect of a SSG-based training programme alone. SSG-based football plans (2 to 4 SSG sessions per week) show athletic performance improvements in football players by improving sprint, repeated sprint ability (RSA) and change of direction (COD) along with muscular and physiological adaptation.