Change Of Direction Performance Research Articles

Change of direction speed and deficit over single and multiple changes of direction: Influence of biological age in youth basketball players

ABSTRACT The study analysed the difference in change of direction (COD) deficit among young male basketball players of different age groups and biological ages and analysed the relationships in COD performance (time and deficit) across single and multiple CODs depending on their biological age. Fifty-four highly-trained male players (U-13 and U-17) were tested on sprinting (25-m) and COD ability over single and multiple CODs through total times and the percentage-based COD deficit (CODD). Results showed that older age groups performed significantly (ES = 0.43–2.32, p < 0.05) better in linear and COD times, especially those players with post-peak height velocity (PHV) (ES = 0.89–1.90). Controlling for age at PHV, no significant differences were found in any group or inter-limb asymmetries. Moderate relationships were found between CODD in the pool data (r = 0.36 to 0.50). All CODD and time relationships in any test (i.e., 180º COD and V-cut) were considerably lower (r= −0.27 to 0.32) across individual biological groups. The study highlights the impact of maturation on COD performance, whereas CODD seems to be not affected. Interestingly, the CODD is independent, highlighting this measurement’s specific nature. Practitioners should use common distances, angles, and the number of CODs linked to biological status to create a COD profile.

Sex-Related Differences in Functional Fitness Outcomes in Older Adults.

Sex-related differences in changes in functional fitness over time were longitudinally assessed in older adults participating in a group-based multimodal exercise program. From a database, functional fitness scores were obtained for 89 older adults (71.6 ± 6.5years old) who had completed two assessments, 5-8years apart. Lower body strength, upper body strength, aerobic endurance, flexibility, and change of direction performances were compared over time and with normative values. Females (p = .02), but not males, had an improvement in upper body strength over time. Females were also more flexible than males at both assessments (p ≤ .02). Of those who had five consecutive assessments, females were more flexible than males (p ≤ .05) and had a faster change of direction ability (p < .001). When compared with normative values, our results indicate that typical time-related functional fitness loss can be attenuated with group exercise. Our results further support the need to tailor exercise prescription according to the individual.

Training on Sand or Parquet: Impact of Pre-Season Training on Jumping, Sprinting, and Change of Direction Performance in Professional Basketball Players

This study examined the effects of combined change of direction (CoD) and plyometric training on sand in basketball players’ jump, sprint, and CoD performances. In total, twenty-five male professional basketball players (age, 24.1 ± 4.2 years; height, 192.5 ± 8.0 cm; body mass, 92.6 ± 11.6 kg) participated in a pre-season intervention study over seven weeks, where two teams completed an identical speed training protocol, either on sand or on a hard surface, while a third team served as the control. All participants followed their regular pre-season training, while the intervention groups additionally performed the training protocol twice weekly. A repeated-measures ANOVA (rANOVA) showed significant interaction effects on the countermovement jump (F = 14.90, p &lt; 0.001), pivot–step–jump test (F = 8.09, p = 0.002), 10 m sprint time (ST) (F = 4.18, p = 0.050), and 20 m ST (F = 8.49, p = 0.002). Moreover, an rANOVA showed significant interaction effects for the CoD performance regarding total time (F = 5.70, p = 0.010) and average velocity prior to the CoD (F = 8.40, p = 0.002) and after the CoD (F = 3.89, p = 0.036). As such, the findings suggest that sand-based training elicits kinematic adaptations, increased muscle activation, and a shift towards concentric force development that all contribute to enhanced athletic capabilities.

Effects of integrative neuromuscular training on change of direction performance in court-based sports players: A systematic review and meta-analysis

This study systematically reviewed and quantified the scientific literature on the effects of integrative neuromuscular training (INT) on change of direction (COD) performance among court-based sports players. A comprehensive keyword search was conducted on December 15, 2022, across six electronic bibliographic databases: SPORTDiscus, PubMed, Web of Science, Academic Search Ultra, Scopus, and Google Scholar. Following the application of eligibility criteria, a total of 23 studies with 901 participants were included in this review. Meta-analysis was employed to estimate the pooled effect size of INT interventions on COD performance. The findings demonstrated that INT interventions resulted in a significant reduction in COD task completion time for court-based sports players, compared to control groups (standard deviation [SD] = 0.38, 95% CI = 0.27, 0.49; I^2 = 98.76%). However, it was observed that the efficacy of INT on COD performance was influenced by factors such as gender, sport type, and specific metrics of COD task measures. Consequently, it is imperative to consider these potential variations when interpreting the results and planning future research. In conclusion, INT exhibited superior effectiveness in improving COD performance compared to control groups among court-based sports players. We recommend that strength and conditioning professionals incorporate INT into their comprehensive conditioning programs. However, it is important to acknowledge the potential variations in outcomes attributable to participant-specific characteristics, including gender, sport type, and the nature of COD tasks. This understanding will facilitate the optimal application of INT, thereby enhancing athletic performance across diverse sporting contexts.

Effects of combined plyometric, strength and running technique training program on change-of-direction and countermovement jump: A two-armed parallel study design on young soccer players

Context and objectivePlayers must be capable to have a good change-of-direction (COD) skill aiming to be the fastest as possible to react immediately to the opponent or even to help players to be more agile since COD is a physical determinant of agility. Thus, the aim of this study was to test the effects of a six-week combined training intervention in the COD and countermovement jump (CMJ) of young soccer players, while comparing with a control group only performing the regular field-based training sessions. MethodsA sample of 80 non-professional players (40 experimental group and 40 control group) between the ages of ten and twelve was taken [(Age: 10.70 ± 1.02)]. The tests that were carried out from the beginning to the end of the intervention were: CMJ test, 505COD Test and Illinois Test. Paired sample t-test was used for determining differences as a repeated measures analysis (pre– post). An ANCOVA test was performed using the pretest as a covariate and the times pre and post as factors. Results and conclusionsRepeated measures ANCOVA revealed significant influence of baseline level on the 5–0–5 COD (p = 0.001; ηp2=0.170), the Illinois (p = 0.018; ηp2=0.070) and the CMJ (p = 0.047; ηp2=0.050). Significant interactions group*time (p < 0.001; ηp2=0.137), 5–0–5 COD (p < 0.001; ηp2=0.274), and CMJ (p < 0.001; ηp2=0.392) were found, while no significant interactions were found in Illinois (p = 0.293; ηp2=0.014). The current research revealed that a combined training intervention consisting of strength training, plyometrics, and running techniques can be significantly beneficial for improving COD performance and CMJ.

The effect of lower inter-limb asymmetries on athletic performance: A systematic review and meta-analysis.

Inter-limb asymmetry refers to an imbalance in performance between the left and right limbs. Discrepancies throughout asymmetry research does not allow practitioners to confidently understand the effect of inter-limb asymmetries on athletic performance. Therefore, this review summarized the current literature using a meta-analytic approach, conforming to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines to identify the association between inter-limb asymmetry and athletic performance. A literature search using PubMed, Web of Science and SPORTDiscus databases yielded 11-studies assessing the effect of inter-limb asymmetries, measured via unilateral jump performance, on bilateral jump, change of direction (COD) and sprint performance in adult sports players. The quality of evidence was assessed via a modified Downs and Black checklist and in compliance with the Grading of Recommendations Assessment Development and Evaluation. Correlation coefficients were transformed via Fishers z (Zr), meta-analysed and then re-converted to correlation coefficients. Egger's regression presented no significant risk of bias. Vertical jump performance was not significantly affected by asymmetry (Zr = 0.053, r = 0.05; P = 0.874), whereas COD and sprint both presented significant weak associations (COD, Zr = 0.243, r = 0.24; Sprint, Zr = 0.203, r = 0.2; P < 0.01). The results demonstrate that inter-limb asymmetries seem to present a negative impact to COD and sprint performance but not vertical jump performance. Practitioners should consider implementing monitoring strategies to identify, monitor and possibly address inter-limb asymmetries, specifically for performance tests underpinned by unilateral movements such as COD and sprint performance.

Effects of Game-Specific Demands on Accelerations during Change of Direction Movements: Analysis of Youth Female Soccer

The aim of this study was to assess center of mass (COM) acceleration and movement during change of direction (COD) maneuvers during a competitive soccer game to elucidate situation-specific demands of COD performance. This information can assist in developing soccer-specific tests and training methods. Fifteen elite-level female youth soccer players were tracked for one game with inertial measurement units (IMU) attached to the lower back. COD movements in combination with situational patterns were identified using high-speed video. LASSO regression was used to identify the most important predictors associated with higher vertical peak accelerations (PAv) of the COM during COD movements. COD angle, running speed, contact, and challenge from the opposition were identified as important features related to higher PAv. This study adds to the literature on the demands of COD performance in soccer match-play. The unique approach with game-specific situational data from female youth players provides increased insight into the game-demands of COD and agility performance. PAv in games was higher with larger COD angles, increased running speed, or with contact when the player was challenged by the opposition. A larger study including more games is warranted to increase confidence in using these variables as a basis for training or testing agility.

Effects of physical training on change of direction performance: A systematic review with meta-analysis

Background One of the most sought-after skills for performance in team sports is change of direction. Training the physical qualities of strength, speed, and power has been used to improve change of direction. These qualities of change of direction have been studied extensively for the last 20 years, and their influence is still questioned. Additionally, it is currently unknown how moderating training variables affect COD performance. Objective This study examines the impact of strength, power, and speed training on change of direction performance. Method Following the PRISMA guidelines, a meta-analysis was conducted. Electronic databases were searched for studies conducted from 1991 to April 2021. All studies identified for inclusion were peer-reviewed and published in English and Spanish and used an athlete population as participants. For all analyses, a significance level is set at p &lt; 0.05. Results Sixty-six articles were included in this meta-analysis. Two hundred fifty-one effect sizes were calculated, representing 2056 participants aged between 12 and 25 years. The global effect size (ES) for each quality is reported and Cochran's Q test: Strength ( N = 48) ES: 0.844 Q = 77.63 (95%CI: 0.65;1.07); Speed (N = 17) ES: 0.70 Q = 5.69 (CI95% = 0.35;1.05); Power (N = 49) ES: 0.85 Q = 47.58 (CI95% = 0.64;1.06); Agility ( N = 57) ES: 1.05 Q = 79.63 (CI95% = 0.86;1.24); Combined training ( N = 13) ES: 0.51 Q = 13.79 (CI95% = 0.14;0.93), and the Control Group ( N = 67) ES: 0.53 Q = 47.40 (IC95% = −0.12;0.23), all ES were statistically significant except control group. The ANOVA-LIKE presented a statistically significant difference between physical qualities and the control group (Sig = 0.000 Q = 69.18). Conclusion The training of strength, speed, power, and agility, are effective training methods for improving change of direction ability. Each of these qualities has one or more moderating variables that influencing its development.

Relationship Between Talent Identification and Change of Direction in Young Basketball Players

Study purpose. Regarding Talent identification (TID) programs, which are an integral part of the selection process for elite-level athletes, the authors detected a lack of evidence, as surprisingly little research has been conducted to elucidate the effects of Change of Direction (COD) test performance on TID in basketball. This study aimed to: i) analyze the anthropometrical measures, performance variables of COD and talents values of each basketball player, ii) conduct through a COD test, a talent identification procedure in basketball, and iii) run a correlation analysis to try to explain the relationship between COD test and basketball talent through either offensive and defensive skills. Materials and methods. A cross-sectional study was conducted on nineteen youth basketball players (age = 15.68 ± 1.20 years; height = 188.84 ± 5.81 cm, and weight = of 75.74 ± 8.37 kg) with at least 3 years of experience. To assess the overall performance of the selected players, a questionnaire regarding either offense or defense variable was used. In addition, players were required to perform V-Cut, 5-0-5 and Illinois Dribbling tests. Single beam photocells (Chronojump Boscosystem) were used and 3D motion capture system with a video camera set at 210 Hz (CASIO EX-ZR800) recorded the entire action. Results. Findings point out that the players’ COD test result correlates positively [505 test (Contact time, r = 0.62, p = 0.004 and COD deficit, r = 0.55, p = 0.01) and Illinois Dribbling test [velocity (r = 0.45, p = 0.04)] with offensive skills whilst it correlates negatively [Illinois Dribbling test (r = -0.46, p = 0.04)] with defensive skills. Conclusions. This study highlights the importance to perform a multidisciplinary approach considering either the coaches’ assessment and players’ COD performance to provide relevant information for TID.

Relevance of force-velocity and change of direction assessments for the ranking position in elite junior tennis players.

This study aimed to correlate sprint mechanical parameters (SMP) of a linear sprint (LS) and a tennis specific modified 505 (Tm505) change of direction (CoD) test obtained with a motorized resistance device (MRD) to the current tennis ranking position (RP). 107 male and 86 female elite junior tennis players nationally ranked in the German Tennis Federation between 10 and 18 years participated in the study. According to their age at peak height velocity (PHV), players were divided into pre-PHV, circa-PHV, and post-PHV groups. SMP were derived from instantaneous time-velocity data of two 20 m all-out LS measured with 333 Hz. Further, mean values from two Tm505 trials with constant 3 kg loading over acceleration-deceleration (1a) and reacceleration (1b) phases were measured with an MRD. SMP of LS and CoD measurements were partially correlated with the current RP in the overall national ranking by controlling for biological maturation. Low to moderate correlations (rs = -0.1 to -0.3) were found between SMP and the RP in all male and female age groups. Correlations of the CoD measurements were overall more pronounced, particularly in girls (rs = -0.44). All linear SMP, like maximal theoretical force (F0; N/kg), and maximal theoretical velocity (v0; m/s), maximal power (Pmax; W/kg), improved over maturation for both genders with Pmax being most important for sprint performance. Further, Pmax was shown to correlate with the girls ranking position (rs = -0.31). During the Tm505, matured players achieved significantly faster overall total and CoD times. Positioning of CoM before CoD enlarged over maturation and was found to correlate to the RP in both sexes. In addition, nearly all SMP significantly correlated to the primary performance outcomes in the Tm505 test in both genders (r = -0.3 to -0.6). CoD performance has a moderate and higher impact on tennis performance compared to LS. CoD performance as well as Pmax achieved a higher relevance for the ranking position predominantly in girls compared to boys. Hence, particularly Pmax as well as the transfer to on-court CoD motor skills should be a central training goal in elite junior tennis players besides technical skills and should depend on maturation status and gender.

The effects of upper and lower limb elastic band training on the change of direction, jump, power, strength and repeated sprint ability performance in adolescent female handball players.

This study aimed to examine the effects of incorporating 10-week elastic band strength training (EBST) program on change of direction, jumping ability, repeated sprint ability, and both muscular strength and power in adolescent female handball players. Participants aged 15.8 ± 0.2 years were divided by playing position, and players from each position were then randomly assigned between the elastic strength (n = 17) and control (n = 17) groups. The experimental group performed periodized upper and lower-body elastic band strength training twice weekly for ten weeks by substitution of some of their regular physical and game preparation. The control group only performed regular handball training. Two-way analyses of variance (group × time) assessed change of direction (COD) via the modified t-agility test, squat jump, countermovement jump, standing long jump, repeated sprint ability (RSA), 1-RM bench press and half squat, and cycle ergometer force-velocity tests for both upper and lower limbs. Relative to the control group, the experimental group enhanced COD performance [p < 0.001; Cohen's effect size (d) = 1.00]; squat and countermovement jump (p = 0.002, d ≥ 0.83), best, mean, and total RSA scores (all p < 0.001, d = 0.92-1.66), 1-RM bench press (p = 0.02, d = 0.59) and half squat (p = 0.009, d = 0.67), all indices of upper limb force-velocity performance (p ≤ 0.025, d = 0.56-1.66), and 3 of 4 indices of lower limb force-velocity performance (p ≤ 0.004, d = 0.75-0.92). We conclude that additional elastic band training performed twice a week for ten weeks improves measures relevant to handball game performance in adolescent female athletes.

Physical testing and strength and conditioning practices differ between coaches working in academy and first team soccer

Scientific guidelines exist regarding strength and conditioning (S&amp;C) best practice, for both first team and academy level soccer. However, it is not known if these research-informed guidelines are followed in such applied settings. The aim of this study was to investigate current S&amp;C practice in first team and academy level (men's and women's) soccer, in multiple countries/continents. A total of 170 participants, who were involved with the delivery of S&amp;C support at their soccer club, completed a comprehensive survey, describing their training methods. Data were analysed using Pearson's chi-square test of independence and independent t-tests. Statistical significance was set to p &lt; 0.05. A greater proportion of academy compared to first team coaches assessed acceleration/sprint (92% vs. 83%, p=0.026), jump (95% vs. 83%, p=0.023) and change of direction performance (77% vs. 61%, p=0.031). The weekly training structure differed between groups, particularly within women's squads, with women's academy coaches reporting the lowest session frequency of all groups (1.59 ± 0.62 session per week, 44 ± 17 min duration). A greater proportion of academy (54%) versus first team (35%) coaches prioritised bodyweight training ( p=0.031), despite a similar distribution of movement patterns trained. Overall, 44% S&amp;C coaches reported using training intensities below strength training guidelines (≥80% 1RM). To conclude, there were many differences in S&amp;C practice between S&amp;C coaches working with first team and academy squads but particularly noteworthy was the greater proportion of academy coaches prioritising bodyweight training compared to first team coaches, which may limit physical development in academy players.

Assessing asymmetries and predicting performance in semiprofessional soccer players

This study aimed to (a) detail the interlimb asymmetries during multi-directional jumping, change of direction and for ankle dorsiflexion range of motion and (b) determine how asymmetries and performance in multi-directional jumping and ankle dorsiflexion predict performance during change of direction tests. Twenty-two male semi-professional players completed a testing session which consisted of unilateral ankle dorsiflexion range of motion, vertical and horizontal unilateral and lateral countermovement jumps and left and right leg 90° (COD90L&amp;R) and 180° (COD180L&amp;R) change of direction tests. No significant differences between limbs were observed for any of the variables ( P &gt; 0.05), though vertical countermovement jump (11.1% ± 9.1%) and dorsiflexion range of motion (10.5% ± 10.3%) imbalances were greater than those during lateral (2.7% ± 2.2%) and horizontal (2.2% ± 1.9%) countermovement jumps, and 90° (3.6% ± 3.1%) and 180° change of direction (2.9% ± 3.6%). Subjects presented 3.4 ± 1.4 real asymmetries (i.e., one greater than the coefficient of variation) across the tests, with all subjects having at least one real asymmetry. Stepwise linear regression models explained a reasonable amount of variance in change of direction180R (70%), COD90L (57%), COD90R (39%), COD180L (23%) using the countermovement jump and dorsiflexion range of motion variables ( P &lt; 0.05). The current findings indicate that semi-professional soccer players have real bilateral asymmetries (particularly in countermovement jump and dorsiflexion range of motion), which practitioners should be cognizant of. Given the prediction value, change of direction performance can be predicted using performance and asymmetries during multi-directional jumping and ankle dorsiflexion.

Novel Curvilinear Sprint Test in Basketball: Reliability and Comparison With Linear Sprint.

Baena-Raya, A, Díez-Fernández, DM, López-Sagarra, A, Martínez-Rubio, C, Soriano-Maldonado, A, and Rodríguez-Pérez, MA. Novel curvilinear sprint test in basketball: reliability and comparison with linear sprint. J Strength Cond Res 37(9): e535-e540, 2023-This study (a) evaluated the reliability of a curvilinear sprint (CS) test to assess kinetic and kinematic outcomes in basketball players, (b) compared the kinetic and kinematic outcomes derived from curvilinear vs. linear sprints (LS), and (c) examined the association of both the CS and LS with change of direction (COD) performance. Thirty young basketball players (17 men and 13 women) competing at the national level (i.e., Spanish Basketball National League) performed a novel CS test around the 3-point line (the 3-point line CS test) to the right and left sides. The maximum and average values of acceleration (ACC), velocity (VEL), and centripetal force (CentF) were measured using Local Positioning System technology (WIMU PRO, Realtrack Systems S.L., Almería, Spain). All outcomes showed a high relative (intraclass correlations coefficient ≥ 0.90) and absolute (coefficient of variation [CV] < 5%) reliability, except the maximal CentF to the right (CV = 5.41%) and left sides (CV = 7.72%). Linear sprints displayed higher ACC and VEL outputs compared with the 3-point line CS test (all p < 0.001). Both sprinting tests were very large to nearly perfect associated with COD performance (LS r range from -0.71 to -0.86; CS r range from -0.68 to -0.94; p < 0.001), and the curvilinear ACC max was the kinematic outcome most strongly associated with COD performance ( r range from -0.73 to -0.94). In conclusion, the 3-point line CS test is reliable to measure CS performance in basketball and presents different kinetic and kinematic features than LS.

Change of Direction Performance and its Physical Determinants Among Young Basketball Male Players.

The main aim of the present study was to examine the effects of the age group (U-15, U-17 and U-19) on change of direction (COD) performance and its specific physical determinants among young basketball male players. Thirty-one young male basketball players (13-18 years) volunteered to participate in this study. The sample was divided into 3 age groups (U-15, U-17, U-19). All the evaluations were carried out in the same order in 3 sessions as follows: 1) body composition, self-reported sexual maturation, COD performance, and intermittent endurance capacity; 2) reactive strength index (RSI), 15-m sprint, and repeated sprint ability (RSA) test; 3) vertical and horizontal jumps and lower-limb strength. The results showed significant differences between groups for age, sexual maturation, endurance capacity, horizontal and vertical jump performances, RSI, COD, RSA, and lower-limb strength (p < 0.05). Significant correlations were identified between COD performances and some physical determinants such as jumping ability and RSA performance (-0.43 < r < 0.85; p ≤ 0.05). In conclusion, there are age effects on COD performance and its specific physical determinants among young basketball male players. The associations between COD performance and its determinants should be considered by practitioners when programing athletic talent development for this population.

Construct Validity and Applicability of a Team-Sport-Specific Change of Direction Test.

Cuts and changes of direction (COD) are frequent movements during games in team sports. Since those movements are seen as a key performance variable, COD assessments are included in performance diagnostics. However, some tests are criticized as they seem to be confounded by variables such as linear sprinting. Therefore, it is suggested that not only total COD time should be assessed, but also the athletes' COD movements should be examined more closely. For example, split times could be analyzed in tests with more than one COD like the Team-Sport-Specific COD (TSS-COD) test. We aimed to investigate the construct validity of the TSS-COD test, focusing on the homogeneity of the different test parts. We also tested how far sprint performance mapped onto COD performance. Test data were analyzed from 154 elite male and female volleyball and basketball athletes. A Fitlight© System was used to assess duration of the TSS-COD test. For the sprint tests, magnetic gates (Humotion GmbH) were used to measure sprint time. Explorative principal component analysis (PCA) was conducted including the test interval duration and the athletes' 5, 10, and 20 m sprint performance, to test the validity of the TSS-COD test. PCA results showed that the start interval formed a factor separate from the other COD sub-intervals. In addition, sprint performance was separated from all COD interval measures. The findings of the PCA were confirmed by split-half validation. Since sprint and COD performance represent independent performance domains within this analysis, we suggest the TSS-COD test to be a valid test to assess COD performance.

Effects of Arm Dominance and Decision Demands on Change of Direction Performance in Handball Players.

This field study investigated the effect of unilateral dominance (handedness of players) on the change of direction speed in a specific cutting manoeuvre with a ball (in the direction of the throwing arm vs. against the direction of the throwing arm) in team handball. In addition, the effect of a cutting manoeuvre in response to an immediate stimulus compared to one planned in advance on the movement speed was analysed. Forty participants (22 male, 18 female, Mage 23 years) performed change of direction actions to the left and the right side (the direction of the throwing arm vs. against the direction of the throwing arm) under planned and reactive (light as visual stimuli) conditions. Change of direction speed was measured post-hoc by video-analyses. The results showed two effects. First, the decision demand in reaction to a visual stimulus reduced the speed in the change of direction compared to the planned action. Second, participants performed their action faster in the direction of the throwing arm than against it. The results replicate the effects of decision demands of previous studies and regardless of the reaction to the stimuli being unspecific, further studies could investigate if specific training can reduce the speed loss due to decision demands. The lateral speed differences of cutting manoeuvres of handball players have been analysed for the first time in this study. This effect could have several causes (e.g., coordination, power, motivation) which should be investigated in future studies in more detail.

Sand and grass surfaces are equally effective in promoting positive adaptations in the sprint performance of elite young soccer players.

This study compared the effects of two sprint-jump training programmes, performed on either sand or grass surfaces, on the sprint and jump performance of elite young soccer players over an 8-week training period. Fifteen under-20 soccer players were randomly allocated to the sand (n = 7) or grass (n = 8) group. Athletes performed 12 training sessions, comprising vertical and horizontal jump exercises, and linear and change-of-direction (COD) sprint drills. Pre- and post-measurements were completed in the following order: vertical jump, sprint speed at 10 m and 17 m, curve sprint (CS), and modified Zigzag COD tests. Between-group differences were determined using a two-way ANOVA with repeated measures and effect sizes (ES). No improvements in jump performance were found in either group. Significant increases were observed in the sand group for acceleration in 0-10 m and for 10- and 17-m linear sprint velocity (ES = 1.15, 1.16, and 1.81, respectively; P < 0.05). In contrast, no significant differences were detected for acceleration and linear sprint velocity in the grass group, comparing pre- and post-tests (ES ranging from 0.01 to 0.47; P > 0.05). Both sand and grass groups revealed similar increases in the CS and COD velocities after the training period (ES ranging from 0.98 to 1.93; P < 0.05). In conclusion, sprint-jump training programmes performed on both grass and sand surfaces elicited significant improvements in CS and COD performances, whereas acceleration and linear sprint velocity increased only in the sand group, after a short-term training period. The sand training surface was proven to be a practical strategy to improve sprint performance in all its forms in soccer players, which is of great interest and importance for coaches and sport scientists working in elite soccer.

Does maturity estimation, 2D:4D and training load measures explain physical fitness changes of youth football players?

ObjectivesThe purpose of the present study was two-fold: (1) To analyse physical fitness changes of youth football players after a full-season; and (2) to examine whether physical fitness changes are explainable by estimated maturity status, 2digit:4digit ratio (2D:4D) from each hand and training load (TL) measures.MethodsTwenty-seven youth elite Under-15 football players were daily monitored for training load measures during 38 weeks. At the beginning and at the end of the season, all players were assessed for physical fitness. Also, the maturity status estimation and the length of the second and fourth digits of both hands were collected at the beginning of the season.ResultsSignificant differences were found for all physical fitness measures after the season. The second and fourth digits of left and right hands had negative moderate correlations with change of direction (COD) changes (r=-.39 to − 0.45 | p = .05 to 0.02). Also, the maturity offset measure had negative moderate correlations with COD changes (r=-.40 | p = .04). From the reported significant correlations, the maturity offset, Left 4D, Right 2D and Right 4D significantly predicted the Mod.505 COD test changes (β = 0.41, p = .04; β = -0.41, p = .04; β = -0.45, p = .02; and β = -0.44, p = .03, respectively).ConclusionThe maturity offset and the 2D:4D measures have the potential to predict COD performance changes over-time in youth football players. Given the lack of associations between the maturity estimation, 2D:4D and training load measures, with the overall physical fitness measures, coaches should rely only at COD changes.

The effects of repeated backward running training on measures of physical fitness in youth male soccer players

ABSTRACT This study explored the effects of an 8-week repeated backward running training (RBRT) programme on measures of physical fitness in youth male soccer players. Youth male soccer players were randomly allocated into a RBRT group (n = 20; 13.95 ± 0.22y) or a control group (CG; n = 16; 14.86 ± 0.29y). The CG continued normal soccer training, while the RBRT group replaced some soccer drills with RBRT twice per week. Within-group analysis revealed that RBRT improved all performance variables (∆-9.99% to 14.50%; effect size [ES] = −1.79 to 1.29; p ≤ 0.001). Meanwhile, trivial-to-moderate detrimental effects on sprinting and change of direction (CoD) speed (∆1.55% to 10.40%; p ≤ 0.05) were noted in the CG. The number of individuals improving performance above the smallest worthwhile change ranged from 65–100% across all performance variables in the RBRT group, whereas<50% in the CG reached that threshold. The between-group analysis indicated that the RBRT group improved performance on all performance tasks more than the CG (ES = −2.23 to 1.10; p ≤ 0.05). These findings demonstrate that substituting part of a standard soccer training regimen with RBRT can enhance youth soccer players’ sprinting, CoD, jumping, and RSA performance.