Can Haematological and Hormonal Biomarkers Predict Fitness Parameters in Youth Soccer Players? A Pilot Study

The study aimed to investigate the correlations among immune, haematological, endocrinological markers and fitness parameters, and assess if the physiological parameters could be a predictor of fitness values. Anthropometric, physical evaluations (countermovement jump—CMJ, 10 m sprint, VO2max, repeated sprint ability—RSA total time and index) and determination of blood (IL-6, IL-10, IL-17A and tumour necrosis factor) and salivary (testosterone and cortisol) samples parameters in 28 young male soccer players (age: 13.0 ± 0.2 years, body mass index (BMI): 19.5 ± 2.2 kg/m2) were analysed. To evaluate the dependence of the variables related to athletic performance, multiple linear regression with backward stepwise elimination was considered. A significant regression equation was found in CMJ (F(5,16) = 9.86, p < 0.001, R2 adjusted = 0.679) and in the RSA index (F(5,16) = 15.39, p < 0.001, R2 adjusted = 0.774) considering only five variables, in a 10 m sprint (F(4,17) = 20.25, p < 0.001, R2 adjusted = 0.786) and in the RSA total time (F(4,17) = 15.31, p < 0.001, R2 adjusted = 0.732) considering only four variables and in VO2max (F(9,12) = 32.09, p < 0.001, R2 adjusted = 0.930) considering nine variables. Our study suggests the use of regression equations to predict the fitness values of youth soccer players by blood and saliva samples, during different phases of the season, short periods of match congestion or recovery from an injury.

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Influence of 2D:4D ratio on fitness parameters and accumulated training load in elite youth soccer players

BMC Sports Science Medicine and Rehabilitation ◽

10.1186/s13102-021-00354-5 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Hadi Nobari ◽

Ana Ruivo Alves ◽

Filipe Manuel Clemente ◽

Jorge Pérez-Gómez

Keyword(s):

Body Mass ◽

Muscular Strength ◽

Perceived Exertion ◽

Knee Extensor ◽

Training Load ◽

Soccer Players ◽

Youth Soccer ◽

Fitness Parameters ◽

Three Stages ◽

Left And Right

Abstract Background Digit ratio (2D:4D) characterized by the length of the second digit (2D) divided by the length of the fourth digit (4D), is a powerful marker of athletic performance. Some studies showed a negative correlation between 2D:4D ratio and sports performances. Objectives The purpose of the present study was three-fold: (1) to analyze the influence of anthropometric and 2D:4D ratio on variations of accumulated training load (ATL) and fitness parameters: maximal oxygen uptake (V̇O2max), countermovement jump (CMJ), isometric muscular strength of the knee extensor for hamstring (ISH) and flexor for quadriceps (ISQ) muscles; along three stages of evaluation of soccer players based on playing positions; (2) to analyze the correlations between 2D:4D ratio and aforementioned parameters; and (3) to investigate if variance in fitness levels and ATL can explain the 2D:4D ratio. Methods Twenty-four elite players under 17 years were daily monitored for their rating perceived exertion and ATL across 24 weeks over the season. Soccer players have also measured in three stages for anthropometric traits and fitness parameters. Results Significant differences were observed between playing positions for body mass, goalkeepers had higher body mass compared to centre-midfielder and winger players. Moreover, there were significant differences in ATL between early-season to mid-season in goalkeepers (P = 0.032). The 2D:4D ratio (left and right) shown largely and negatively association with muscular strength (ISQ: r = − 0.80; r = − 0.78, P ≤ 0.001, ISH: r = − 0.63; r = − 0.62, P = 0.001, respectively) and VO2max changes (r = − 0.55, P = 0.005; r = − 0.50, P = 0.013, respectively); lastly, both 2D:4D ratio significantly predicted changes in muscular strength and VO2max in young soccer players. Conclusions Goalkeepers tended to have higher body mass compared to centre-midfielder and winger players; and 2D:4D ratio revealed a mighty predictor of physical fitness changes in soccer players. Evidence should be helpful to professionals to highlight the usefulness of the 2D:4D into the identification of talent, but also to optimize young players' performance.

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Internal, external and repeated-sprint demands in small-sided games: A comparison between bouts and age groups in elite youth soccer players

PLoS ONE ◽

10.1371/journal.pone.0249906 ◽

2021 ◽

Vol 16 (4) ◽

pp. e0249906

Author(s):

Richard Hauer ◽

Paul Störchle ◽

Bettina Karsten ◽

Harald Tschan ◽

Arnold Baca

Keyword(s):

Age Groups ◽

Soccer Players ◽

Internal Load ◽

Youth Soccer ◽

Training Tool ◽

Low Intensity ◽

Repeated Sprint ◽

Age Related ◽

Younger Age ◽

Image Position

This study investigated the activity profile during small-sided games (SSG) in elite youth soccer players. Internal load (IL) including heart rate (HR) and external load (EL) such as distance covered in different speed-zones (SZ) were collected from forty-eight players of three different teams (U15, U16, U18). The investigation included a total of eighteen 5vs.5 SSGs, each consisting of four 2-minute bouts on a 40x32m pitch during spring season. Total group results (n = 48) showed a reduction in total-distance (p = 0.001; ηp2 = 0.12), high-intensity-running (p = 0.009; ηp2 = 0.09), and low-intensity-running distance (p = 0.028; ηp2 = 0.07) between bouts. Similarly, a reduction in the number of both acceleration-low (p = 0.001; ηp2 = 0.12) and deceleration-high (p = 0.003; ηp2 = 0.11) values was observed. Additionally, time spent in HR-zones 3 and 4 (p≤0.007; ηp2 ≥ 0.10), increased, with a reduction in HR-zone 1 (p = 0.000, ηp2 = 0.25). Age group comparison showed less distance covered in SZ 1 (p≤0.000; ηp2 = 0.56) and greater deceleration-high values (p≤0.038; ηp2 = 0.32) in U15 players compared to other age groups. Further, U15 showed lower values in low-intensity-running compared to U18 (p = 0.038; ηp2 = 0.22). No age-related differences were found for IL and repeated sprint ability (RSA) values. The higher EL in younger age groups should be taken into account when implementing soccer specific SSGs. In addition, HRmean values between 80–85% of HRmax and RSA numbers, which are similar to match-play data, indicate SSGs as an effective training tool to prepare youth soccer athletes for the demands of competition.

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Test–Retest Reliability of Skill Tests in the F-MARC Battery for Youth Soccer Players

Perceptual and Motor Skills ◽

10.1177/0031512519866038 ◽

2019 ◽

Vol 126 (5) ◽

pp. 1006-1023 ◽

Cited By ~ 1

Author(s):

Alexis Padrón-Cabo ◽

Ezequiel Rey ◽

Alexandra Pérez-Ferreirós ◽

Anton Kalén

Keyword(s):

Intraclass Correlation ◽

Young Male ◽

Soccer Players ◽

Limits Of Agreement ◽

Retest Reliability ◽

Youth Soccer ◽

Test Retest Reliability ◽

Standard Error Of Measurement ◽

Absolute Reliability ◽

Error Of Measurement

This study aimed to evaluate the test–retest reliability of soccer skill tests belonging to the F-MARC test battery. To avoid bias during talent identification and development, coaches and scouts should be using reliable tests for assessing soccer-specific skills in young male players. Fifty-two U-14 outfield male soccer players performed F-MARC soccer skill tests on two occasions, separated by 7 days. After familiarization, we administered two trial sessions of five skill tests: speed dribbling, juggling, shooting, passing, and heading. We assessed absolute reliability by expressing the standard error of measurement as a coefficient of variation with 95% limits of agreement, and we assessed relative reliability with the intraclass correlation coefficient and with Pearson’s correlation ( r). The results demonstrated satisfactory relative and absolute reliability for speed dribbling, right foot juggling, short passing, shooting a dead ball right, shooting from a pass, heading in front, and heading right. However, reliability values for left foot juggling, chest-head-foot juggling, head-left-foot-right foot-chest-head juggling, long pass, and shooting a dead ball left tests were not strong enough to suggest their usage by coaches in training or sport scientists in research.

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Endocrine Responses to Various 1 × 1 Small-Sided Games in Youth Soccer Players

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16244974 ◽

2019 ◽

Vol 16 (24) ◽

pp. 4974

Author(s):

Paweł Chmura ◽

Tomasz Podgórski ◽

Marek Konefał ◽

Andrzej Rokita ◽

Jan Chmura ◽

...

Keyword(s):

Rest Period ◽

Young Male ◽

Serum Cortisol ◽

Free Testosterone ◽

Soccer Players ◽

Total Testosterone ◽

Exercise Protocol ◽

Youth Soccer ◽

Study Results ◽

Variable Duration

The aim of this study was to determine relationships between repeated 1 × 1 small-sided games (SSGs) (variable duration, constant work-to-rest ratio) and the concentration of steroid hormones and characteristic fatigue markers in youth soccer players. Eighteen young male soccer players were assigned at random to two experimental groups: E1—undertaking a six 30 s one-on-one SSGs with a 2 min rest period; and E2—playing six 45 s SSGs with a 3 min rest interval. Capillary blood was collected from the players at rest, after the last game, and 15 and 30 min after the exercise protocol. The variables assessed included serum cortisol (C), free testosterone (FT) and total testosterone (TT). An effect was observed between the measurement times (TT (F = 15.26, p ≤ 0.0001), FT (F = 6.86, p = 0.0006)). In terms of cortisol (C) levels, no interactions or effect between the studied groups were revealed, but an interaction was found (F = 4.01, p = 0.0126) and the effect appeared between the measurement times (F = 11.16, p ≤ 0.0001). The study results show that in all likelihood, longer rest intervals in repeated 30 s 1 × 1 SSGs can reduce catabolic reactions and hence the risk of overtraining in youth soccer players.

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Running Performance and Hormonal, Maturity and Physical Variables in Starting and Non-Starting Elite U14 Soccer Players During a Congested Match Schedule

Journal of Human Kinetics ◽

10.2478/hukin-2021-0096 ◽

2021 ◽

Vol 80 (1) ◽

pp. 287-295

Author(s):

Vinicius Zanetti ◽

Marcelo Saldanha Aoki ◽

Paul Bradley ◽

Christopher Carling ◽

Thomas Kisil Marino ◽

...

Keyword(s):

High Speed ◽

Soccer Players ◽

Running Performance ◽

Salivary Testosterone ◽

Youth Soccer ◽

Wide Range ◽

Significant Difference ◽

The Difference ◽

Biological Maturity ◽

Test Level

Abstract This study examined changes in match running performance (MRP) in Under-14 soccer players (13.5 ± 0.7 yrs) during a congested match schedule (CMS) (4 matches played within a 5-day period). It also examined the difference in salivary testosterone (sT) concentration, somatic maturation, jumping tests, and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) between the players selected to play (SLG; group who participated in all matches) and players non-selected to play (NSG). A significant difference was observed for the frequency of decelerations (DEC) across matches (match 4 vs. matches 1, 2 and 3; p = 0.05; partial ƞ2 = 0.20). No difference between matches was observed for total running distance (TRD), high-speed running distance (HSRD), and frequency of accelerations (ACC) (p > 0.05). A wide range for within-player coefficient of variation (CV) values was observed for all MRP variables (range: 10.5 = TRD to 30.6 = HSRD). No difference between SLG and NSG for any of the assessed variables was observed (p > 0.05). The findings suggest that DEC was the most pertinent variable for monitoring changes in MRP during the CMS. In addition, at an elite youth soccer level, the biological maturity and fitness might not influence selection to play.

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Heart Rate Response and Match Repeated-Sprint Performance in Chinese Elite Youth Soccer Players

Asian Journal of Physical Education & Recreation ◽

10.24112/ajper.171875 ◽

2011 ◽

Vol 17 (2) ◽

pp. 42-49

Author(s):

Del P. WONG ◽

Karim CHAMARI ◽

Anis CHAOUACHI ◽

Tze Chung LUK ◽

Patrick Wing Chung LAU

Keyword(s):

Heart Rate ◽

Recovery Period ◽

Interval Training ◽

Cardiovascular Fitness ◽

Sprint Performance ◽

Soccer Players ◽

Active Recovery ◽

Youth Soccer ◽

Repeated Sprint ◽

Soccer Teams

LANGUAGE NOTE | Document text in English; abstract also in Chinese. The purpose of this study is to investigate the heart rate (HR) repose and repeated-sprint performance throughout the match among Chinese elite youth soccer players. Two elite youth soccer teams each consisted of 11 players participated in the study. The HR measurement and repeated-sprint test were conducted (age: 17.1±0.85, height: 173± 5.2cm; weight: 64.2± 8.1kg). HR was recorded every 5s throughout the match, while repeated-sprint consisted of three 30m sprints separated by a 25s active recovery period that was conducted: 5min before the match (T1), 5min before the end of the first half (T2), 5min before the start of the second half (T3), and 5min before the end of the second half (T4). HR was in the range of 160-169bpm for 25% of total play time, followed by 170-179bpm for 23.6%. HR during the 46-60min was significantly lower than other intervals (P<0.05), and repeated-sprint time at T3 was significantly slower than others. The intensity of the match was lower than those found in European players, indicating the cardiovascular fitness and repeated-sprint performance are needed among the players. High-intensity and low-volume interval training, and re-warm up before the start of second half are suggested in the training program. 本研究旨在測定中國青年足球運動員比賽時的心率及重覆衝跑測試表現。對兩支分由11人組成的足球隊運動員(年齡17.1±0.85歲，身高：173±5.2釐米，體重; 64.2±8.1公斤)進行了心率測量以及重覆衝跑測試。比賽時每5秒鍾記錄一次心率。重覆衝跑測試由3次30米衝跑組成，每次有25秒動態休息。重覆衝跑測試共進行四次，分別在：賽前5分鐘(T1)，中場前5分鐘(T2)，下半場開始前5分鐘(T3)及比賽結束前5分鐘(T4)進行。結果在25%的比賽時間內，運動員的心率在每分鐘160-169之間，其次是23.6%的時間內為每分鐘170-179。在46-60分鐘的比賽中，運動員的心率顯著低於其他時段(P<0.05),而運動員在第三次重覆衝跑測試時的速度顯著低於其他三次測試。本次研究結果顯示比賽強度低於歐洲青年足球員進行的同類測試，說明中國青年足球運動員需要加強心肺功能及提高重覆衝跑的表現。建議訓練時進行大強度低密度的間歇訓練，及在比賽中場開始前再次進行熱身。

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Effect of listening to music on repeated-sprint performance and affective load in young male and female soccer players

Sport Sciences for Health ◽

10.1007/s11332-018-0518-2 ◽

2019 ◽

Vol 15 (2) ◽

pp. 337-342

Author(s):

Mohamed Tounsi ◽

Hamdi Jaafar ◽

Asma Aloui ◽

Zouhair Tabka ◽

Yassine Trabelsi

Keyword(s):

Young Male ◽

Sprint Performance ◽

Soccer Players ◽

Male And Female ◽

Repeated Sprint

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Short-Term Cardiac Autonomic Recovery after a Repeated Sprint Test in Young Soccer Players

Sports ◽

10.3390/sports7050102 ◽

2019 ◽

Vol 7 (5) ◽

pp. 102

Author(s):

Cesar Cavinato Cal Abad ◽

Lucas Adriano Pereira ◽

Vinicius Zanetti ◽

Ronaldo Kobal ◽

Irineu Loturco ◽

...

Keyword(s):

Time Course ◽

Soccer Players ◽

Short Term ◽

Post Exercise ◽

Youth Soccer ◽

Passive Recovery ◽

Repeated Sprint Ability ◽

Repeated Sprint ◽

Mean Square Difference ◽

Sprint Ability

The aim of this study was to describe the time course (within 2 h post-exercise) of heart rate variability (HRV) recovery following a traditional repeated sprint ability (RSA) test applied to youth soccer players. Twenty-four young soccer players (18.4 ± 0.5 years) undertook the following assessments: (1) 10 min rest in the seated position for HRV assessment; (2) a repeated sprint ability (RSA) test; (3) passive recovery in the seated position for 10 min, immediately after finishing the RSA test and 1 h and 2 h post-RSA test. During the HRV measurements (using the natural log of root mean square difference of successive normal RR intervals—lnRMSSD) the participants were instructed to assume a comfortable sitting position, remaining awake and breathing spontaneously for 10 min. Magnitude-based inference was used in the analyses. After the RSA test, the post-1 h measure was almost certainly lower than the resting measure, but almost certainly higher than the lnRMSSD measured post-RSA test. The lnRMSSD post-2 h was likely lower than the resting lnRMSSD and very likely higher than post-1 h. In conclusion, lnRMSSD is severely depressed after performing an RSA test, and reactivation is incomplete after 2 h of passive recovery. This result should be considered by practitioners when applying successive training sessions within intervals shorter than 2 h.

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