Keiner, M, Kadlubowski, B, Sander, A, Hartmann, H, and Wirth, K. Effects of 10 months of speed, functional, and traditional strength training on strength, linear sprint, change of direction, and jump performance in trained adolescent soccer players. J Strength Cond Res 36(8): 2236–2246, 2022—The current study aimed to compare the effects of plyometric and sprint vs. functional vs. strength training on linear sprint (LS 20 m), change of direction (COD; i.e., turning right and left), jump (squat jump [SJ]), and maximum strength (1 repetition maximum [1RM] for a squat) performance in elite adolescent soccer players. A longitudinal design was chosen, and 48 elite male youth were recruited. The athletes were divided into 4 groups (a traditional strength training group [STG], a plyometric and sprint training group [PSTG], a functional training group [FTG], and a control group [CG]). The intervention groups trained for 10 months with additional sessions added to their regular soccer training (4–5 sessions per week); the additional training (2 sessions a week [each about 60 minutes]) consisted of plyometric and sprint training, functional training, and traditional strength training for the PSTG, FTG, and STG, respectively. Data were analyzed using analysis of variance with repeated measurements. The effect sizes were calculated using Hedges g. This study showed significantly superior performance increases with traditional strength training compared with sprint and jump training and functional training for maximum strength (compared with all other groups g = 0.98–1.61), SJ (g = 0.52–0.87 compared with FGT and CG; not significantly different from PSTG), COD (direction of rotation right: compared with all other groups g = 1.58–2.12; direction of rotation left: no significant differences), and 20-m LS (compared with all other groups g = 0.86–1.39) performance over time. Traditional strength training is recommended to increase strength and speed-strength variables and should therefore be given high priority in athletic training programs for elite youth soccer players.

Change of direction (COD) is a performance-limiting factor in team sports. However, there are no exact definitions describing which physical abilities limit COD performance in soccer. Nevertheless, different COD tests are used or have been recommended as being equally effective in the professional practice of measuring COD performance. Therefore, the aim of this study was to evaluate the relationship between different COD tests, and to test the independence and generalizability of these COD tests in soccer. As such, 27 elite youth soccer players were randomly recruited and were tested in different COD tests (i.e., Illinois agility test (IAT), T agility test (TT), 505 agility test (505), Gewandtheitslauf (GewT), triangle test (Tri-t), and square test (SQT)). Bivariate Pearson correlation analysis was used to assess the relationships between the COD tests. The Benjamini–Hochberg method was used to control for the false discovery rate of the study at 0.05. This investigation calculated explained variances of 10% to 55% between performances in the different COD tests. This suggested that the tests covered different aspects or task-specific characteristics of the COD. Therefore, coaches and sport scientists should review and select different tests with a logical validity, based on the requirement profiles of the corresponding sport.

Change of direction (COD) performance has an essential role in soccer. In the literature, there is a wide range of explained variance in correlation analyses between linear-sprint performance, concentric power and maximum strength and COD performance. Therefore this study has (1) analyzed the influence of linear-sprint performance, concentric power and maximum strength on COD performance in elite youth soccer players and (2) compared the calculated influence on the different COD tests. To answer the research questions, 67 elite youth soccer players were tested. The linear-sprint (10 m, [LS]) performance, concentric power (squat jump [SJ]) and maximum strength (1 repetition maximum [1 RM]) and COD (measured via the Illinois agility test [IAT], the 505 agility test [505], the agility test of the German Soccer Association [GewT], and the triangle test [TriT]) were assessed. The Pearson correlation analysis was used to assess the relationship. Benjamini and Hochberg’s method, which was used to control the study-wise false discovery rate, was 0.05. The LS performance had the greatest impact on COD performance with a wide range of explained variance between the different COD tests (r2 = 0.18 to 0.39). However, SJ compared to LS performance had lower influence, but also a wide range of explained variance (r2 = −0.02 to −0.29). Correlations for 1 RM and COD test were calculated with r2 = −0.01 to −0.09. Thus, (1) the greater the similarity between the performance tests (i.e., LS, SJ, 1 RM) and the COD tests, the higher the explained variance between the variables in question. Furthermore, (2) as the different COD tests are affected to different degrees by linear-sprint, concentric power and maximum strength performance, it might be concluded that the tests have a different physiological requirement profile. Therefore, coaches and sport scientists must review and select different tests with logical validity, based on the requirement profiles of soccer.

This study aims to analyze the influence of relative strength performance, determined by parallel back squats (REL SQ), on 30 m sprinting (LS) and on jumping performance (squat [SJ], countermovement [CMJ]) in a large sample (n = 492) of elite youth soccer players. The soccer players were divided into subgroups based on their strength performance: strength level 1 (0.0–0.5 REL SQ), strength level 2 (>0.5–1.0 REL SQ), strength level 3 (>1.0 to 1.5 REL SQ), strength level 4 (>1.5 to 2.0 REL SQ), and strength level 5 (>2.0 REL SQ). The results of this study show that REL SQ explains 45–53% (r = |0.67–0.73|) of the variance of SJ, CMJ, and LS for the total sample. Strength levels 2–4 showed similar coefficients of correlation in jumping performance (r = |0.42–0.55|) and strength levels 2 and 3 in sprint performance (r = |0.41|). The respective extreme strength levels showed lower coefficients of correlation with the sprinting and jumping performance variables (r = |0.11–0.29|). No coefficients could be calculated for strength level 5 because no athlete achieved an appropriate strength level (>2.0 REL SQ). The data from this study show a clear influence of REL SQ on sprint and jump performance, even in a large sample.

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.

Introduction: Speed-strength performance is important during human movements such as jumping, sprinting, and change of direction (COD) tasks, which are a substantial part of sports practice. Sex and age seem to influence performance output in young persons; however, few studies have focused on the influence of sex and age measured via standard protocols of performance diagnostics.Method: Therefore, the aim of this study was to investigate the influence of age and sex on linear sprint (LS), COD sprint, countermovement jump (CMJ) height, squat-jump (SJ) height, and drop-jump (DJ) height performance in untrained children and adolescents via a cross-sectional analysis. This study comprised 141 untrained male and female participants 10–14 years of age.Results: The results showed the influence of age in male participants on speed-strength performance, while in female participants, age did not significantly influence performance parameters. Moderate to high correlations between sprint and jump performance (r = 0.69–0.72), sprint and COD sprint performance (r = 0.58–0.72), and jump and COD sprint performance (r = 0.56–0.58) were found.Discussion: Based on the data from this study, it appears that the growth phase of age 10–14 does not necessarily lead to improvements in athletic performance. To ensure holistic motor development, female subjects in particular should be provided with specific training interventions with a focus on strength and power.

Background: Good change-of-direction sprint performance is considered important for basketball players. Regarding the components of a change-of-direction task, a correlation between the linear sprint and concentric power output can be assumed. Previous studies have shown heterogeneous correlation coefficients between different change-of-direction (COD) tests and linear and jump performance.Methods: Therefore, 47 trained youth basketball players (13.2 ± 3.6 years; 34 males and 13 females) were recruited. Linear sprint (10 and 20 meters), squat jump, and COD sprint tests (the zig-zag test and triangle test) were conducted. One-tailed Pearson correlation analysis was used to assess the relationship of sprint and jump performance with COD tests, and two-trailed analysis was used to assess the relationship between the different COD tests.Results: This study showed that both linear sprint variables and concentric power output explained the variance in the different COD tests in a homogeneous manner (r 2 = 0.14 to 0.42). The correlation coefficients did not statistically differ between the male and female players, and the different COD tests correlated moderately with one another (r 2 = 0.42 -0.46). For both analyses, the intercorrelation results did not differ significantly between sexes and analyzed correlation coefficients. Conclusion:It is recommended that the squat jump, 10-to 20 meter linear sprint, zig-zag and triangle tests are included in batteries of tests conducted in youth basketball players.COD tests with the same structure may have similar physiological requirements; however, these tests have task-specific characteristics. Therefore, coaches and sport scientists must review and select different tests with logical validity based on sport-specific requirements.