The effect of weighted vest use during in-season, small-sided games training on young soccer players' performance

The aim of the present study was to investigate the effect of weighted vest on-field small-sided games (SSG) soccer training, during the in-season period, on body composition and soccer-specific performances, in young, trained soccer players. A counterbalance study design was adopted, in which the fourteen well-trained players (age: 19.1 ± 0.5 yrs, body mass: 70.3 ± 5.3 kg, body height: 180.3 ± 3.0 cm, body fat: 9.2 ± 4.1%) performed both the Interventional (Vest) and Control (Con) training routines (6 weeks/season; 5 training sessions/week; 1 match/week), in different occasions (winter/spring period). Con group followed a regular weekly training plan. When the Con group performed their intense training sessions, Vest group performed only the on-field SSGs training wearing a vest (12.5% of athletes' body mass). All the evaluations were performed one week before and after each training period. Statistical analyses include repeated ANOVA and T-test (p < 0.05). Significant increases in sprinting, jumping, change of direction (COD), aerobic and anaerobic performances were observed only after Vest intervention (-4.7 ± 2.2% to 11.2 ± 4.2%; p < 0.05). Significant changes were observed only after Vest training, compared to Cont (p < 0.05). These results suggest that using a weighted vest, during the in-season, onfield SSG training two times/week induces greater increases in young soccer players' sprinting, jumping, COD, aerobic and anaerobic performances.

"You Are Not Wrong About Getting Strong:" An Insight Into the Impact of Age Group and Level of Competition on Strength in Spanish Football Players

OBJECTIVE

This study aimed to compare the maximum and rapid force production of Spanish football players and explore the differences between age group and level of competition.

METHODS

A cross-sectional study was developed to evaluate the peak force (PF), relative PF, and rate of force development over 250 ms (RFD0-250) during the isometric midthigh pull between groups of football players based on age group (senior vs junior) and level of competition (national vs regional). Using a portable isometric rig, 111 football players performed 2 isometric midthigh-pull trials on a force plate. Two-way analysis of variance with Bonferroni post hoc correction was applied, and statistical significance was set at P ≤ .05. The PF, relative PF, and RFD0-250 0, 25, 50, 75, and 100 percentiles were also calculated and descriptively reported, separated by age group and level of competition.

RESULTS

The analysis of variance revealed a significant main effect of the level of competition for the PF (P < .001), relative PF (P = .003), and RFD0-250 (P < .001). There was a significant main effect of age group for the PF (P < .001). There was a significant interaction effect of the age group × level of competition for relative PF (P = .014). National players were stronger than regional players on the PF and RFD0-250 (P < .001). Senior players were stronger than junior players for the PF (P < .001).

CONCLUSIONS

Maximum and rapid force production are crucial for Spanish football players as they progress in both level of competition and age group. Practitioners should encourage young football players to prioritize strength development to improve their athletic performance.

A survey into the current fitness testing practices of elite male soccer practitioners: from assessment to communicating results

This study provides insight into the current fitness testing practices in elite male soccer. One hundred and two practitioners from professional soccer leagues across 24 countries completed an online survey comprising 29 questions, with five sections: a) background information, b) testing selection, c) testing implementation, d) data analysis, and e) data reporting. Frequency analysis was used to evaluate the responses to fixed response questions and thematic analysis was used for open-ended questions to generate clear and distinct themes. Strength (85%) and aerobic capacity (82%) represent the most frequently assessed physical qualities. Scientific literature (80%) is the most influential factor in testing selection and practitioners conduct fitness testing less frequently than their perceived ideal frequency per season (3.6 ± 2 vs. 4.5 ± 2). Time and competitive schedule were the greatest barriers to fitness testing administration. Practitioners mostly used a 'hybrid' approach (45%) to fitness testing, blending 'traditional' (i.e., a day dedicated to testing) and 'integrated' (i.e., testing within regular training sessions) methods. Microsoft Excel is the most used software for data analysis (95%) and visualization (79%). An equal use of the combination of best and mean scores of multiple trials (44%) and the best score (42%) was reported. Comparing a player's test performance with previous scores (89%) was the most common method for interpreting test results. However, only 38% considered measurement error. Digital displays and verbal feedback are the most common data reporting methods, with different data reporting processes for coaches and players. Practitioners can use data and findings from this study to inform their current testing practices and researchers to further identify areas for investigation, with the overarching aim of developing the field of fitness testing in elite male soccer.

Quantifying technical load and physical activity in professional soccer players during pre-season matches with IMU technology

This study aimed to record, analyze and quantify professional soccer players' technical (TL) and physical load (PL) in friendly matches to compare their records during the first and second halves and between players with different positions. Eighteen professional soccer players, 24.6 ± 2.7 years, 1.78 ± 0.3 height (m), 74.6 ± 4.5 body mass (kg), 9.8 ± 2.2 body fat (%), and 65.6 ± 2.7 maximal oxygen consumption (VO2max, ml·kg-1·min-1) were monitored during six preseason friendly matches to analyze the activity profile using technical and physical variables through inertial measurement unit (IMU). No significant differences were found between the periods for the TL and PL. Significant differences were found between specific positions: Full Back (FB: n = 4), Central Defender (CD: n = 3), Midfielder (MD: n = 4), Winger (WG: n = 4), and Forward (FW: n = 3), both the TL and PL. We conclude that the PL profile based on his playing position is independent of the development of the PL shown during friendly matches. The monitoring, quantifying, and controlling of the TL added to the PL provides a more holistic vision of soccer players in friendly matches. The relative ease IMU application technology offers an alternative with less time-cost and more significant benefits than other types of technologies applied up to now.

Microdosing: Old Wine in a New Bottle? Current State of Affairs and Future Avenues

Purpose: Microdosing of exercise aims to deliver smaller daily training doses but at a higher weekly frequency, adding up to a similar weekly volume as in nonmicrodosed training. This commentary critically discusses this concept, which appears to be a rebranding of the “old” distributed practice of motor learning. Development: We propose that microdosing should relate to the minimal dose that develops or at least maintains the selected capacities or skills as this training dose matters to practitioners, especially during the in-season period. Moreover, microdosing has been applied mainly to develop strength and endurance, but abilities such as sprinting and changing direction could also be microdosed, as well as technical–tactical skills. Conclusions: The concept of microdosing should be reframed to avoid redundancy with the concept of distributed practice while providing valuable information concerning the minimum doses that still generate the intended effects and the thresholds that determine whether a dose is “micro” or not.

Inter- and intra-microcycle external load analysis in female professional soccer players: A playing position approach

This study analyzes the inter- and intra-differences in external load across the microcycle in professional female soccer players. External load during four consecutive microcycles (i.e., M1, M2, M3, and M4) and training sessions (i.e., MD-4, MD-3, MD-2, and MD-1) and a match day (i.e., MD) were registered in seventeen female professional soccer players (age: 26.3 ± 4.6 years; height: 166.3 ± 6.1 cm; body mass: 59.8 ± 6.8 kg; and body mass index: 21.6 ± 1.7 kg·m^-2) who belonged to the same team in Spanish first division. A 10-Hz GPS that integrated a 100-Hz triaxial accelerometer was used to register external load. The results showed lower decelerations in M2 compared to M1 and M3 (p < 0.05), lower high-intensity distance (>16.0 km·h^-1) in M3 vs. M2, and greater relative sprint distance (>21.0 km·min^-1) in M4 vs. M1 and M3 (p < 0.05). MD-3 registered the highest load for all variables (p < 0.05). Forwards (FWs) performed (p < 0.05) significantly more sprints (meters and number > 21.0 km·h^-1) than central midfielders (CMs) and central defenders (CDs) in MD-2 and MD. Both, fitness and conditioning staff should pay special attention to the external loads for each playing position in training sessions to optimize the training process.

Monitoring Postmatch Fatigue During a Competitive Season in Elite Youth Soccer Players

CONTEXT

Countermovement jump (CMJ) and perceived wellness measures are useful for monitoring fatigue. Fatigue indicators should simultaneously show sensitivity to previous load and demonstrate influence on subsequent physical output; however, these factors have not been examined.

OBJECTIVE

To explore the efficacy of CMJ and wellness measures to both detect postmatch fatigue and predict subsequent physical match output in elite youth soccer players.

DESIGN

Cross-sectional study.

PATIENTS OR OTHER PARTICIPANTS

Sixteen soccer players (18 ± 1 years) from 36 English Football League Youth Alliance League fixtures.

MAIN OUTCOME MEASURE(S)

Physical match outputs (total distance, high-speed running, very high-speed running, and accelerations and decelerations [AD]) were recorded using a 10-Hz global positioning system and 200-Hz accelerometer device during competitive match play. The CMJ height and perceived wellness were assessed weekly and daily, respectively, as indirect indicators of fatigue. Four subunits of wellness (perceived soreness, energy, general stress, and sleep) were measured using customized psychometric questionnaires.

RESULTS

Simple linear regression showed that match AD predicted energy (R2 = 0.08, P = .001), stress (R2 = 0.09, P < .001), and total wellness (R2 = 0.06, P = .002) at 2 days postmatch. The CMJ (R2 = 0.05, P = .002), stress (R2 = 0.08, P < .001), sleep (R2 = 0.03, P = .034), and total wellness (R2 = 0.05, P = .006) measures at 5 days prematch predicted AD during the subsequent match.

CONCLUSIONS

The CMJ and wellness measures may be useful for detecting postmatch fatigue. Wellness scores, but not CMJ, at 5 days prematch influenced subsequent match output and therefore may be used to plan and periodize training for the upcoming microcycle.

In-season training responses and perceived wellbeing and recovery status in professional soccer players

This study aimed to describe professional soccer players' training responses during a competitive season and to investigate the relationship between these responses with wellbeing and recovery indices. Thirteen professional soccer players from the same Spanish Second Division team were monitored during a sixteen-week in-season period. Players' external loads were analyzed using global positioning measurement units (GPS). Additionally, subjective reporting of sleep quality, sleep duration, fatigue, muscle soreness, and stress were assessed with a customized wellness questionnaire at the beginning of each training session. A two-step cluster analysis identified profiles of different training responses generally described as lower-demand sessions, intermediate-demand sessions, running-based sessions, and sprint-based sessions; which were discriminated by different total distance covered and high-intensity actions. Interestingly, no probabilistic interactions were found between these training responses with wellbeing and recovery markers (i.e., Bayes factor < 1 suggesting no evidence, for all the variables). These findings may raise concerns about using self-reporting tools, as they show that players' wellness data is probably not accounted for when coaching staff plan and optimize the training process. However, results should be interpreted with caution, due to representing a single team and coaching staff.

The Impact of a Repeated Sprint Training Program on Performance Measures in Male Field Hockey Players

ABSTRACT

Taylor, L and Jakeman, JR. The impact of a repeated sprint training program on performance measures in male field hockey players. J Strength Cond Res XX(X): 000-000, 2021-Sprint interval training (SIT) has been shown to be effective at improving athletic performance in laboratory studies, but the efficacy of SIT programs incorporated into normal training schedules is poorly considered. This study aimed to investigate the impact of a running SIT intervention applied to competitive athletes within a training program and to consider whether an uphill or flat (horizontal) SIT protocol had different effects on performance changes over time. Eighteen male hockey players (mean ± SD: age, 20.7 ± 0.9 years; hockey training experience, 9.9 ± 3.0 years) completed 2 sessions of SIT per week for 8 weeks, with intensity progressively increasing from 6 sprints in week 1 to 12 sprints in week 8. Subjects were randomly allocated to a flat or uphill (6% gradient) training condition (n = 9) and completed 30-m maximal sprint efforts with a 30-second recovery. Performance measures, including squat jump, 30-m sprint speed, and repeated sprint time, all improved significantly (p ≤ 0.05). Squat jump performance improved by 3.84 (d = 0.8) and 3.55 (d = 0.7) in the flat and uphill groups, respectively. Thirty-meter sprint speed improved by 0.06 (d = -0.4) and 0.10 (d = -0.7), and repeated sprint performance also improved, with the fastest of recorded sprints after intervention being 0.06 and 0.04 faster in the flat and uphill groups, respectively. Supplementing a normal hockey training week with SIT can have a positive impact on performance measures in male university hockey players. Furthermore, using an uphill training modality had a small, nonsignificant additional positive effect to some performance adaptations.

Profiling and Relationship between Sprint Time and Cardiovascular Fitness during In-Season’s Training among Professional Soccer Players

The purpose of this study was to examine the sprint time and cardiovascular fitness among professional soccer players during in-season’s training sessions. Thirty participants who officially registered as Perbadanan Kemajuan Negeri Perak Football (PKNP) Club professional soccer players participated in this study. Data were collected during actual in-season training sessions from December 2016 to April 2017. Sprint time performance was determined by the 20m sprint test and 20m Yoyo Intermittent Recovery Test Level 1 was used to determine the cardiovascular fitness level of the players. Repeated Measures and Pearson Correlation Coefficient was used to analyzed the data, there was significant improvement (p<0.05) for sprinting performance from pre-test (3.59 ± 0.36 sec) to post-test (3.20 ± 0.14 sec). There was also a significant improvement for cardiovascular performance from pre-test (68.65 ± 3.88 mhkg-1·min-1) to post-test (75.40 ± 5.45 mhkg-1·min-1) throughout the four months of training periods. There was a significant relationship (p<0.05) between sprint time performance and cardiovascular fitness performance for all six series testing. Thus, it can be concluded that throughout the process of monitoring, the player’s performance can be identified, as showed in this study there was an improvement on sprinting performance and cardiovascular fitness performance throughout six series testing, which mean players undergone relevant training program during the in-season training session.

The relationship between isometric mid-thigh pull variables and athletic performance measures: empirical study of English professional soccer players and meta-analysis of extant literature

BACKGROUND

There is currently limited evidence available to support the use of the isometric mid-thigh pull (IMTP) within professional soccer. The aim of this study was to analyze the association between IMTP variables, with common markers of athletic performance capability.

METHODS

Eleven professional development soccer players (age: 20±2 years, stature: 1.82±0.10 m, mass: 76.4±12.8 kg) performed IMTP, 5 m and 10 m accelerations, maximal sprint speed (MSS), countermovement jump (CMJ), and the 505 change of direction test (COD).

RESULTS

Relative and absolute peak force (PF) and force at 50, 100, 150 and 200 ms values were measured during the IMTP. Relative F150, F200, PF displayed large to very large correlations with MSS (r=0.51, r=0.66, and r=0.76 respectively), while absolute PF also displayed a large correlation with MSS (r=0.57). Relative and absolute PF showed large correlations with CMJ height (r=0.54 and r=0.55 respectively). Relative F150 and F200 highlighted large correlations with COD ability (r=-0.68 and r=-0.60 respectively). Relative F200 and PF had a large negative correlation with 10 m acceleration (r=-0.55 and r=-0.53 respectively).

CONCLUSIONS

This study provides an important contribution to knowledge within the area of IMTP testing in professional soccer by evidencing the prominence of the isometric force generating capacity as an underpinning factor in relation to athletic capability.