Landing Kinematics in Elite Male Youth Soccer Players of Different Chronologic Ages and Stages of Maturation

Context: Despite the high frequency of knee injuries in athletes, few researchers have studied the effects of chronologic age and stage of maturation on knee-joint kinematics in male youth soccer players. Objective: To use a coach-friendly screening tool to examine knee-valgus scores for players of different ages and at different stages of maturation. Design: Cross-sectional study. Setting: Academy soccer clubs. Patients or Other Participants: A total of 400 elite male youth soccer players aged 10 to 18 years categorized by chronologic age and stage of maturation based on their years from peak height velocity (PHV). Main Outcome Measure(s): Knee valgus was evaluated during the tuck-jump assessment via 2-dimensional analysis. Frontal-plane projection angles were subjectively classified as minor (<10°), moderate (10°–20°), or severe (>20°), and using these classifications, we scored knee valgus in the tuck jump as 0 (no valgus), 1 (minor), 2 (moderate), or 3 (severe). Results: A trend toward higher valgus scores was observed in the younger age groups and the pre-PHV group. The lowest frequency of no valgus occurred in the U18 and post-PHV groups. The highest percentages of severe scores were in the U13 and pre-PHV groups for the right limb. Knee-valgus scores were lower for both lower extremities in the U18 group than in all other age groups (P < .001) except the U16 group. Scores were lower for the post-PHV than the pre-PHV group for the right limb (P < .001) and both pre-PHV and circa-PHV groups for the left limb (P < .001). Noteworthy interlimb asymmetries were evident in the U14, U15, and circa-PHV groups. Conclusions: Reductions in knee valgus with incremental age and during the later stages of maturation indicated that this risk factor was more prevalent in younger players. Interlimb asymmetry may also emerge around the time of the peak growth spurt and early adolescence, potentially increasing the risk of traumatic injury.

Download Full-text

Hopping and Landing Performance in Male Youth Soccer Players: Effects of Age and Maturation

International Journal of Sports Medicine ◽

10.1055/s-0043-114009 ◽

2017 ◽

Vol 38 (12) ◽

pp. 902-908 ◽

Cited By ~ 6

Author(s):

Paul Read ◽

Jon Oliver ◽

Mark De Ste Croix ◽

Gregory Myer ◽

Rhodri Lloyd

Keyword(s):

Injury Risk ◽

Soccer Players ◽

Height Velocity ◽

Chronological Age ◽

Peak Height Velocity ◽

Temporary Reduction ◽

Cross Sectional ◽

Male Youth ◽

Youth Soccer ◽

Increased Risk

AbstractQuantifying hopping and landing performances can assist coaches in identifying young male soccer players who may be at increased risk of injury. The influence of chronological age and maturation on these measures in this population is unknown. Single leg hop for distance (SLHD) and 75% horizontal hop and stick landing force (75%Hop) were examined in a cross-sectional sample (N=400) of elite male youth soccer players. Between-group differences for both chronological age (U11–U18) and stage of maturation (pre-, circa- or post-peak height velocity (PHV)) were analyzed. Absolute 75%Hop increased with both age and maturation. Apart from the U18s, pre-PHV and U11–U12 players displayed the greatest relative landing forces compared to all other groups (p<0.001; d=0.56–0.93). Absolute and relative SLHD were greatest in the U18s and post-PHV players (p<0.001; d=0.35–2.04). A trend showed increased SLHD with each consecutive age group although a reduction in performance was identified in the U13s (d=0.50–0.59). High volumes of accumulated soccer participation in the U18s may lead to altered landing strategies indicative of high injury risk. A temporary reduction in hop performance in the U13s may also be linked to a period of adolescent awkwardness.

Download Full-text

Influence of Maturation Status on Eccentric Hamstring Strength Improvements in Youth Male Soccer Players After the Nordic Hamstring Exercise

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2019-0184 ◽

2020 ◽

Vol 15 (7) ◽

pp. 990-996

Author(s):

Benjamin Drury ◽

Thomas Green ◽

Rodrigo Ramirez-Campillo ◽

Jason Moran

Keyword(s):

Training Program ◽

Peak Height ◽

Soccer Players ◽

Height Velocity ◽

Peak Height Velocity ◽

Control Groups ◽

Male Youth ◽

Youth Soccer ◽

Before And After ◽

And Control

Purpose: This study examined the effects of a 6-week Nordic hamstring exercise (NHE) program in youth male soccer players of less mature (pre–peak height velocity [PHV]) or more mature (mid/post-PHV) status. Methods: Forty-eight participants were separated into pre-PHV (11.0 [0.9] y) or mid/post-PHV (13.9 [1.1]) groups and further divided into experimental (EXP) and control groups with eccentric hamstring strength assessed (NordBord) both before and after the training program. Participants in the EXP groups completed a periodized NHE program performed once or twice weekly over a 6-week period. Results: The NHE program resulted in moderate and small increases in relative eccentric hamstring strength (in newtons per kilogram) in the pre-PHV EXP (d = 0.83 [0.03–1.68]) and mid-PHV EXP (d = 0.53 [−0.06 to 1.12]) groups, respectively. Moderate increases in the same measure were also seen in the between-groups analyses in the pre-PHV (d = 1.03 [0.23–1.84]) and mid-PHV (d = 0.87 [0.22–1.51]) groups, with a greater effect observed in the former. Conclusion: The results from this study demonstrate that a 6-week NHE program can improve eccentric hamstring strength in male youth soccer players, with less-mature players achieving mostly greater benefits. The findings from this study can aid in the training prescription of NHE in youth male soccer players.

Download Full-text

Comparison of Drop Jump and Tuck Jump Knee Joint Kinematics in Elite Male Youth Soccer Players: Implications for Injury Risk Screening

Journal of Sport Rehabilitation ◽

10.1123/jsr.2019-0077 ◽

2020 ◽

Vol 29 (6) ◽

pp. 760-765 ◽

Cited By ~ 1

Author(s):

Rhodri S. Lloyd ◽

Jon L. Oliver ◽

Gregory D. Myer ◽

Mark B. De Ste Croix ◽

Josh Wass ◽

...

Keyword(s):

Injury Risk ◽

Vertical Jump ◽

Knee Kinematics ◽

Frontal Plane ◽

Young Male ◽

Soccer Players ◽

Height Velocity ◽

Peak Height Velocity ◽

Male Youth ◽

Youth Soccer

Context: Despite the popularity of jump-landing tasks being used to identify injury risk factors, minimal data currently exist examining differences in knee kinematics during commonly used bilateral jumping tasks. This is especially the case for rebounding-based protocols involving young athletes. Objective: To compare the frontal plane projection angles (FPPAs) during the drop vertical jump (DVJ) and tuck jump assessment (TJA) in a cohort of elite male youth soccer players of varying maturity status. Methods: A total of 57 male youth soccer players from an English championship soccer club participated in this study. Participants performed 3 trials of the DVJ and TJA, during which movement was recorded with 2-dimensional video cameras. FPPA for both right (FPPA-r) and left (FPPA-l) legs, with values <180° indicative of medial knee displacement. Results: On a whole-group level, FPPA-r (172.7° [7.4°] vs 177.2° [11.7°]; P < .05; effect size [ES] = 0.46) and FPPA-l (173.4° [7.3°] vs 179.2° [11.0°]; P < .05; ES = 0.62) were significantly greater for both limbs in the TJA compared with the DVJ; however, these differences were less consistent when grouped by maturity status. FPPA-r during the TJA was significantly and moderately greater in the circa-peak height velocity (PHV) group compared with the post-PHV cohorts (169.4° [6.4°] vs 175.3° [7.8°]; P < .05; ES = 0.49). Whole-group data showed moderate relationships for FPPA-r and FPPA-l between the TJA and DVJ; however, stronger relationships were shown in circa- and post-PHV players compared with the pre-PHV cohort. Conclusions: Considering that the TJA exposed players to a larger FPPA and was sensitive to between-group differences in FPPA-r, the TJA could be viewed as a more suitable screen for identifying FPPA in young male soccer players.

Download Full-text

Does Resisted Sled Towing Improve the Physical Qualities of Elite Youth Soccer Players of Differing Maturity Status?

Journal of Science in Sport and Exercise ◽

10.1007/s42978-020-00087-w ◽

2021 ◽

Author(s):

Rhys Morris ◽

Tony Myers ◽

Stacey Emmonds ◽

Dave Singleton ◽

Kevin Till

Keyword(s):

Body Mass ◽

Bayesian Regression ◽

Soccer Players ◽

Height Velocity ◽

Regression To The Mean ◽

Peak Height Velocity ◽

Maturity Group ◽

Youth Soccer ◽

Professional Soccer ◽

The Impact

Abstract Purpose Sled towing has been shown to be an effective method to enhance the physical qualities in youth athletes. The aim of this study was to evaluate the impact of a 6-week sled towing intervention on muscular strength, speed and power in elite youth soccer players of differing maturity status. Method Seventy-three male elite youth soccer players aged 12–18 years (Pre-Peak Height Velocity [PHV] n = 25; Circa-PHV n = 24; Post-PHV n = 24) from one professional soccer academy participated in this study. Sprint assessments (10 m and 30 m), countermovement jump and isometric mid-thigh pull were undertaken before (T1) and after (T2) a 6-week intervention. The training intervention consisted of 6 weeks (2 × per week, 10 sprints over 20 m distance) of resisted sled towing (linear progression 10%–30% of body mass) during the competitive season. Bayesian regression models analysed differences between T1 and T2 within each maturity group. Results There were minimal changes in strength, speed and power (P = 0.35–0.80) for each maturity group across the 6-week intervention. Where there were changes with greater certainty, they are unlikely to represent real effect due to higher regression to the mean (RTM). Conclusion It appears that a 6-week sled towing training programme with loadings of 10%–30% body mass only maintains physical qualities in elite youth soccer players pre-, circa-, and post-PHV. Further research is required to determine the effectiveness of this training method in long-term athletic development programmes.

Download Full-text

Coaches’ Evaluations of Match Performance in Academy Soccer Players in Relation to the Adolescent Growth Spurt

Journal of Science in Sport and Exercise ◽

10.1007/s42978-020-00072-3 ◽

2020 ◽

Vol 2 (4) ◽

pp. 359-366 ◽

Cited By ~ 1

Author(s):

Megan Hill ◽

Sam Scott ◽

Darragh McGee ◽

Sean Cumming

Keyword(s):

Age Groups ◽

Soccer Players ◽

Growth Spurt ◽

Age Group ◽

Youth Soccer ◽

Impact Performance ◽

Rate Of Growth ◽

Talent Selection ◽

Selection Decisions ◽

Player Performance

AbstractIndividual differences in biological maturation present challenges for coaches involved with youth soccer players. Youth in the same chronological age group vary in terms of stage of maturity (pre, circum- and post-pubescent) and rate of growth, but how this affects coaches’ evaluations of player performance is unknown. The aim of this study was to compare youth soccer coaches’ evaluations of players match performances before, during and post growth spurt in a professional English soccer academy across four seasons. Two hundred and seventy-eight male soccer players in the under-9 to under-16 age-groups had their performances evaluated by their coach on a 4-point Likert scale. For each game, players were categorised by their maturity status estimated using percentage of predicted adult height at the time of observation. A one-way ANCOVA controlling for the level of opposition and game outcome revealed that coaches’ evaluations declined from the pre- to during growth spurt stages, however, this was only significant in the under 12 age-group. Further, coaches’ evaluations increased again in the post-growth spurt stage, although only significant in the under 15 age-group. Coaches evaluations of player performance appear to vary in accordance with stage of maturity and rate of growth. Practitioners in youth soccer should understand the extent to which maturity status may adversely impact performance and consider this when making talent selection decisions.

Download Full-text

Injury Risk and Injury Burden Are Related to Age Group and Peak Height Velocity Among Talented Male Youth Soccer Players

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967118811042 ◽

2018 ◽

Vol 6 (12) ◽

pp. 232596711881104 ◽

Cited By ~ 11

Author(s):

Hans Jan Bult ◽

Maarten Barendrecht ◽

Igor Joeri Ramon Tak

Keyword(s):

Injury Risk ◽

Age Groups ◽

Peak Height ◽

Soccer Players ◽

Height Velocity ◽

Incidence Density ◽

Chronological Age ◽

Peak Height Velocity ◽

The Mean ◽

Injury Burden

Background: The relationship between injury risk (IR) in age groups and periods around peak height velocity (PHV) remains unclear. PHV is defined as the moment of the largest increase in body height. Purpose: To investigate injury risk and injury burden as functions of growth velocity (periods around PHV) and chronological age groupings (under 12 years [U12] to U19) in talented youth male soccer players. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 170 players from the youth academy of a Dutch soccer club (highest professional league: Eredivisie) were observed for 1 to 3 seasons. Injuries, exposure, PHV age, and chronological age were registered. The injury incidence density (IID) and injury burden per 1000 hours of soccer participation, with 95% CIs, were calculated for 5 PHV periods and 7 age groups. These were compared with the overall cohort results using incidence ratios (IRs) and burden ratios (BRs) with 95% CIs. Results: The mean age at PHV was 14.4 ± 0.65 years (range, 12.8-16.5 years). The mean IID for the total cohort was 8.34 injuries per 1000 hours (95% CI, 7.71-9.02). Compared with the overall mean, a significantly higher IID was found for PHV period 4+5 (IR, 1.31 [95% CI, 1.00-1.71]; P = .049) and for the U15 group (IR, 1.49 [95% CI, 1.24-1.79]; P < .001). The overall injury burden was 58.37 injury days per 1000 hours (95% CI, 56.66-60.13). In PHV period 4+5, the injury burden was significantly higher (BR, 1.53 [95% CI, 1.39-1.68]; P < .001) when compared with the overall mean. Also, compared with the overall mean, the injury burden was higher in the U16 (BR, 1.48 [95% CI, 1.39-1.58]; P < .001), U15 (BR, 1.28 [95% CI, 1.19-1.38]; P < .001), and U17 groups (BR, 1.21 [95% CI, 1.13-1.31]; P < .001). Conclusion: Talented young soccer players were more prone to injuries during the 6 months after PHV (31% above overall mean) as well as in the U15 group (49% above overall mean). Based on the higher injury burden in the U16 (48%), U15 (28%), and U17 (21%) groups, we suggest that research on injury risk factors and preventive measures should primarily target these age groups. Additional interventions based on PHV may be of limited value from a screening perspective. Further research is needed on the interaction between age groups and PHV periods.

Download Full-text

Improvement of Physical Performance Following a 6 Week Change-of-Direction Training Program in Elite Youth Soccer Players of Different Maturity Levels

Frontiers in Physiology ◽

10.3389/fphys.2021.668437 ◽

2021 ◽

Vol 12 ◽

Author(s):

Dorsaf Sariati ◽

Raouf Hammami ◽

Hassane Zouhal ◽

Cain C. T. Clark ◽

Ammar Nebigh ◽

...

Keyword(s):

Training Program ◽

Effect Size ◽

Soccer Players ◽

Height Velocity ◽

Adherence Rate ◽

Peak Height Velocity ◽

Post Intervention ◽

Significant Group ◽

Youth Soccer ◽

Change Of Direction

Background: Change-of-direction (CoD) is a necessary physical ability of a field sport and may vary in youth players according to their maturation status.Objectives: The aim of this study is: to compare the effectiveness of a 6-week CoD training intervention on dynamic balance (CS-YBT), horizontal jump (5JT), speed (10 and 30-m linear sprint times), CoD with (15 m-CoD + B) and without (15 m-CoD) the ball, in youth male soccer players at different levels of maturity [pre- and post-peak height velocity (PHV)].Materials and Methods: Thirty elite male youth soccer players aged 10–17 years from the Tunisian first division participated in this study. The players were divided into pre- (G1, n = 15) and post-PHV (G2, n = 15) groups. Both groups completed a similar 6-week training program with two sessions per week of four CoD exercises. All players completed the following tests before and after intervention: CS-YBT; 5 JT; 10, 30, and 15 m-CoD; and 15 m-CoD + B, and data were analyzed using ANCOVA.Results: All 30 players completed the study according to the study design and methodology. Adherence rate was 100% across all groups, and no training or test-related injuries were reported. Pre-PHV and post-PHV groups showed significant amelioration post-intervention for all dependent variables (after test > before test; p < 0.01, d = 0.09–1.51). ANOVA revealed a significant group × time interaction only for CS-YBT (F = 4.45; p < 0.04; η2 = 0.14), 5JT (F = 6.39; p < 0.02; η2 = 0.18), and 15 m-CoD (F = 7.88; p < 0.01; η2 = 0.22). CS-YBT, 5JT, and 15 m-CoD improved significantly in the post-PHV group (+ 4.56%, effect size = 1.51; + 4.51%, effect size = 1.05; and -3.08%, effect size = 0.51, respectively), more than the pre-PHV group (+ 2.77%, effect size = 0.85; + 2.91%, effect size = 0.54; and -1.56%, effect size = 0.20, respectively).Conclusion: The CoD training program improved balance, horizontal jump, and CoD without the ball in male preadolescent and adolescent soccer players, and this improvement was greater in the post-PHV players. The maturity status of the athletes should be considered when programming CoD training for soccer players.

Download Full-text

Assessing Differences in Cardiorespiratory Fitness With Respect to Maturity Status in Highly Trained Youth Soccer Players

Pediatric Exercise Science ◽

10.1123/pes.2017-0185 ◽

2018 ◽

Vol 30 (2) ◽

pp. 216-228 ◽

Cited By ~ 6

Author(s):

Greg Doncaster ◽

John Iga ◽

Viswanath Unnithan

Keyword(s):

Oxygen Uptake ◽

Cardiorespiratory Fitness ◽

Peak Height ◽

Peak Oxygen Uptake ◽

Running Economy ◽

Fat Free Mass ◽

Soccer Players ◽

Height Velocity ◽

Peak Height Velocity ◽

Youth Soccer

Purpose: The purpose of the study was to examine differences in measures of cardiorespiratory fitness and determinants of running economy with respect to maturity status in a group of highly trained youth soccer players. Methods: A total of 21 highly trained youth soccer players participated in this study. On separate visits, players’ peak oxygen uptake (VO2peak), running economy at 3 different speeds [8 km·h−1, 80% gaseous exchange threshold (GET), and 95% GET], and pulmonary oxygen uptake (VO2) kinetics were determined. Players also performed a Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Players were categorized as either “pre-PHV” (peak height velocity) or “mid-PHV” group using the measure of maturity offset. Independent t tests and Cohen’s d effect sizes were then used to assess differences between groups. Results: The mid-PHV group was significantly taller, heavier, and advanced in maturity status. Absolute measures of VO2peak were greater in the mid-PHV group; however, when expressed relative to body mass, fat-free mass, and theoretically derived exponents, VO2peak values were similar between groups. Pre-PHV group presented a significantly reduced VO2 response, during relative submaximal running speeds, when theoretically derived exponents were used, or expressed as %VO2peak. VO2 kinetics (tau) were faster during a low (standing) to moderate (95% GET) transition in the pre-PHV group. Yo-Yo IR1 performance was similar between groups. Conclusion: Although measures of VO2peak and Yo-Yo IR1 performance are shown to be similar between groups, those categorized as pre-PHV group display a superior running economy at relative submaximal running speeds and faster taus during a low to moderate exercise transition than their more mature counterparts.

Download Full-text

Differences in Squat Jump, Linear Sprint, and Change-of-Direction Performance among Youth Soccer Players According to Competitive Level

Sports ◽

10.3390/sports9110149 ◽

2021 ◽

Vol 9 (11) ◽

pp. 149

Author(s):

Michael Keiner ◽

Andreas Kapsecker ◽

Tobias Stefer ◽

Björn Kadlubowski ◽

Klaus Wirth

Keyword(s):

Age Groups ◽

Cross Sectional Study ◽

Soccer Players ◽

Cross Sectional ◽

Male Youth ◽

Squat Jump ◽

Youth Soccer ◽

Change Of Direction ◽

Talent Selection ◽

Selection Test

The aim of this investigation was to analyze significant differences in performance depending on the level of play (elite vs. amateur) in youth soccer players (under 17 years. old (U17) and U19). A cross-sectional study was conducted, and 45 elite and amateur male youth soccer players (16.56 ± 0.9 years old) were evaluated in their performances in squat jump (SJ), 10 m linear sprint (LS), 20 m LS, 505 agility test (505) and Illinois agility test (IAT). Differences in performances were analyzed with a 2 × 2 MANOVA, post-hoc ANOVAs, and Hedges’ g (g) for pairwise comparisons of subgroups (level of play and age group). This investigation showed that the elite player performance was significantly (p < 0.05) better in all performance tests than amateur players in both age groups. Interestingly, this investigation showed that the more complex the target exercise, the larger the effect sizes for group differences (SJ: g = 0.64–1.18, LS: g = 0.05–2.23, change-of-direction (COD): g = 3.01–6.84). The SJ, LS, 505, and IAT may prove useful in talent selection test batteries to separate between competitive levels in youth soccer players.

Download Full-text