In-season Period Research Articles

Effects of a Short-Term Detraining Period on the Physical Fitness in Elite Youth Soccer Players: A Comparison Between Chronological Age Groups.

Padrón-Cabo, A, Lorenzo-Martínez, M, De Dios-Álvarez, V, Rey, E, and Solleiro-Durán, D. Effects of a short-term detraining period on the physical fitness in elite youth soccer players: a comparison between chronological age groups. J Strength Cond Res XX(X): 000-000, 2024-The aim of this study was to examine the effects of a 2-week in-season training cessation on neuromuscular and endurance performance in 2 different age groups of elite youth soccer players. A total of 30 players belonging to the under-15 (U15, n = 17) and under-17 (U17, n = 13) age groups of a Spanish professional soccer academy participated in the study. The following tests were assessed before and after the training cessation period: squat jump (SJ), countermovement jump (CMJ), 20-m sprint with 5-m and 10-m split times, modified 505 change of direction, and 30-15 Intermittent Fitness Test (30-15 IFT). The results showed significant and similar performance impairments between the 2 age groups in SJ (p = 0.020), CMJ (p = 0.044), 20-m sprint (p < 0.001), and 30-15 IFT (p < 0.001). The U17 players evidenced greater impairment than the U15 players in 5-m (p = 0.006) and 10-m (p = 0.002) sprint performance. However, there was no significant change (p = 0.070) in the players' change of direction performance. These findings provide valuable information for strength and conditioning coaches, suggesting the need for targeted interventions to mitigate the effects of detraining on neuromuscular and endurance performance during short-term in-season training cessation periods in elite youth soccer players. Special attention should be paid to maintaining sprint performance during short-term detraining periods in U17 players.

Effects of Bulgarian bag training on bio-motor fitness, physiological, haematological, and performance in young adult male Kabaddi players

Kabaddi demands high bio-motor fitness and physiological robustness in players. The Bulgarian Bag, known for its dynamic training potential, offers multi-planar movements to enhance strength, endurance, and coordination. However, its impact on Kabaddi players still needs to be explored. To assess the effects of Bulgarian Bag training (BBT) on bio-motor fitness, physiological, hematological, and performance measures in young adult Kabaddi players. A total of 30 participants were randomly assigned to either the BBT Group (BBTG) (n = 15; age = 20.73 ± 1.83 years; weight = 72.56 ± 7.27 kg; height = 175.20 ± 6.03 cm) or the active Control Group (CG) (n = 15; age = 20.80 ± 1.69 years; weight = 71.86 ± 4.75 kg; height = 171.46 ± 6.06 cm). The training intervention lasted 12 weeks and was conducted during the in-season period. All outcome parameters tests were conducted before and after the intervention, including agility (AG), explosive strength (ES), shoulder strength (SS), muscular strength (MS), resting heart rate (RHR), VO2max, red blood cells (RBC), white blood cells (WBC), hemoglobin (HG), and playing ability (PA). The ANCOVA analysis revealed significant between-group differences in all physical fitness measures at post-test. Specifically, the BBTG showed significant improvements in AG, ES, SS, MS, RHR, VO2Max, RBC, WBC, HG, and PA (d = 0.75 to 3.28; Δ0.50% to 16.37%). Moreover, the BBTG group significantly reduced resting heart rate (d = 0.75; Δ-3.31%). In contrast, no significant changes were reported in the Control Group (CG) between pre- and post-tests (d = 0.00 to 0.78; Δ-0.08% to 4.59%). Integrating BBTG into the training program of young adult male Kabaddi players yielded beneficial effects across multiple parameters of bio-motor fitness, physiological, hematological, and playing ability. The findings reveal the potential of BBTG as a valuable training method for enhancing Kabaddi performance and overall athletic conditioning. Keywords: Kabaddi Player, Bulgarian bag training, bio motor, physiological, haematological

Menstrual Cycle Phases and Elite Female Soccer During Training: Exercise Load Perception and External Workload Monitoring

BACKGROUND: Female soccer has grown exponentially in the last years, however studies on women soccer players are very few compared with male ones and several inconsistencies are reported in the literature for female players. Physiological hormonal fluctuations during the different moments of menstrual cycle could have important implications on soccer performance, therefore, the aim of the present study was to investigate the impact of menstrual cycle phases on external and internal loads in elite women’ soccer players during an in-season training period, and to describe the internal-external training load relationship, in relation to different menstrual cycle moments. METHODS: 16 elite players from Italian soccer first division were monitored for 12 weeks. The main internal parameter (rate of perceived exertion - RPE), external variables (total time, total distance, high speed running - HSR, numbers of accelerations/decelerations) and session-RPE were collected during training sessions and analyzed trough a repeated-measures ANOVA to identify differences in the MC weeks. Menstrual cycle was monitored through daily questionnaires and was divided into four phases: menstruation week, pre-ovulation, post-ovulation, and pre-cycle. RESULTS: HSR and total distance were significantly lower during menstruation week than post-ovulation week (18318.70 ±1802.04 m vs 20358.41 ± 1639.27 m, respectively; p=0.022). A significant correlation was found in pre-cycle week between RPE and total distance (r=0.545; p=0.029), and between session-RPE with total distance (r=0.514; p=0.042) and total time (r=0.502; p=0.048). When considering the whole menstrual cycle, weak and moderate correlations were found for RPE and session-RPE with total time, total distance and HSR. CONCLUSION: Appropriate menstrual cycle monitoring is required for better interpretation of players’ response in elite women’s soccer training, given that during menstruation week, external load variables could be impaired. RPE and session-RPE values do not change statistically with changes in external variables, and their relationship showed unclear results, highlighting caution when interpreting them, and suggesting their use in combination with other parameters, especially during early follicular phase.

Light load jump squat and plyometric training enhance jumping, sprinting, change of direction, and balance performance of male soccer players (U-19): a randomized controlled trial.

In sports science, optimizing athletic performance is pursued through an emerging approach that combined light-loaded squat (LLS) training and plyometric jump training (PJT), targeting strength, power, and neuromuscular adaptations, particularly beneficial for the dynamic demands of youth soccer. The aim of this study was to examine the effect of a combined LLS training and PJT program on athletic performance and balance in youth soccer players. Thirty-two male players were randomly assigned to two groups: an experimental group (EG: N.=16; age: 18.56±0.51 years; body mass: 66.87±4.99 kg; height: 1.78±0.07 m) and a control group (CG: N.=16; age: 18.68±0.47 years; body mass: 67.93±4.58 kg; height: 1.77±0.07 m) from the same U19 team of a professional club voluntarily participated in the study. Squat jump (SJ), countermovement jump (CMJ), horizontal jump (HJ), drop jump (DJ), 30 m sprint (30 mS), change of direction ability (4×5 m sprint test [S 4×5 m]) and static balance (the stork balance) performance tests were carried out in the week before and the week after the 8 weeks with combined LLS and PJT period. The two-way analysis of variance (ANOVA) was used for all tests. The results of this study show that the EG had significantly greater improvements than the CG in all tests (all P<0.001). Also, EG experienced higher performance between preintervention and post intervention measures (all P<0.05). There was no significant difference between the two groups in the 4×5mS performance (P>0.05). We conclude that coaches may be advised to use the combined LLS and PJT since it is as effective as traditional methods and perfect for sports and activities requiring fast, explosive movements during the in-season period than regular training.

Habitual Nocturnal Sleep, Napping Behavior, and Recovery Following Training and Competition in Elite Water Polo: Sex-Related Effects.

To examine nocturnal sleep patterns, napping behaviors, and subjective wellness responses of elite water polo players within an in-season week and to identify whether sleeping patterns differ between men and women. Sleep characteristics of 10 male and 17 female professional water polo players were objectively assessed during 1week of the in-season period, including 5 training days, 1 match day, and 1day of rest. Internal load (rating of perceived exertion × duration of training or match) was assessed 30 minutes posttraining or postmatch, and the total quality of recovery was recorded every morning. A series of multilevel models were used to analyze the data. Time in bed and wake-up time were earlier on both training (P < .001) and rest days (P < .001) than on the day of the match. Internal workload did not predict any of the players' sleeping patterns. Midday naps predicted less time in bed (P = .03) and likely less sleep time (P = .08). The total quality of recovery was predicted only by the total sleep time (P < .01). Women exhibited higher sleep efficiency (P < .001), less waking after sleep onset (P = .01), and a lower number of awakenings (P = .02) than men. The current results indicate that the nocturnal sleep patterns of elite water polo players are not associated with internal load and that women display better nocturnal sleep quality compared with men. As long naps interfere with nocturnal sleep, and total nocturnal sleep time predicts total quality of recovery, we suggest that athletes follow hygiene sleep strategies to facilitate adequate nocturnal sleep and next-day recovery.

Exploring the impact of sleep on emotional and physical well-being in professional cricketers: a cohort study over an in-season training period.

Professional athletes navigate a multitude of unique challenges associated to sport-specific factors (e.g., training, travel and competition) and non-sport factors (e.g., performance pressure, stress and anxiety) that can interfere with healthy sleep behaviors. Sleep plays a key role in proper biopsychosocial development as well as short- and long-term biological, physical, psychological, and cognitive health. As poor sleep quality is known to impair proper brain function, this study aimed to investigate the effect of sleep quality on a professional athlete's ability to train, recover, and perform, as well as their overall emotional and physical well-being. A cohort study was performed in 40 professional male cricket athletes from the Dutch national cricket team (mean age 26.5 ± 5.1 years). The athletes were monitored across a 22 weeks in-season training period. Sleep quality and overall emotional and physical well-being were assessed using daily sleep diaries and questionnaires which scored the readiness to train, stress levels, fatigue, muscle soreness and flu symptoms respectively. Quality of sleep and subsequent association with the consecutive elements of the well-being questionnaire were assessed through statistical using the student t-test and clinical differences with the methodology of Osoba and colleagues: <5% "no change", 5%-10% "little change"; 10%-20% "moderate change"; and >20% "very much change". The results demonstrated that the professional athletes assessed their sleep quality as average with a mean score of 3.4 out of 5. Lower perceived quality of sleep (<75th percentile) was correlated with a decreased readiness to train (mean score 3.2 [IQR: 3.0-4.0] vs. 3.5 [IQR: 3.0-5.0]; P < 0.001) and increased extent of muscle soreness (2.7 [IQR: 2.0-3.0] vs. 2.3 [IQR: 2-3]; P < 0.001), stress level (mean score 2.3 [IQR: 2.0-3.0] vs. 1.9 [IQR: 1.0-2.0]; P < 0.001) and perceived fatigue (mean score 2.9 [IQR: 2.0-3.0] vs. 2.3 [IQR: 2.0-3.0]; P < 0.001). Likewise, in patients with lower perceived quality of sleep, the proportion of players presenting with flu symptoms increased over 4-fold (4.1% vs. 17%; P < 0.001). This study highlights that good sleep quality positively influences the overall emotional and physical well-being of professional athletes. Our results emphasize the importance of targeted sleep interventions to improve sleep quality and subsequently optimize psychological and physiological wellness.

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

ABSTRACT 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.

Epidemiology of Injury and Illness in North American Professional Men's Soccer: Comparing COVID-19 Lockdown With Previous Seasons.

After COVID-19 lockdown, studies across Europe and Asia examined its effect on professional soccer injury rates and severity; however, COVID-19 lockdown influence on injuries in United States men's professional soccer has not been evaluated. Injury and illness rates during the 2020 season were higher than the previous 2 seasons. Retrospective observational cohort study. Level 3. Medical staff from participating Major League Soccer (MLS) clubs entered injuries and athletic exposures during the study period into a league-wide electronic medical record system. Injury rate and severity were analyzed to examine differentials between the 2020 COVID season and historical controls. The injury incidence rate per 1000 hours in 2020 was 10.8, ie, higher than 2018 (5.4) and 2019 (5.0) (P < 0.05). Training injury incidence rate increased in 2020 (8.9) compared with 2018 (2.5) and 2019 (2.6) (P < 0.05), whereas match injury incidence decreased in 2020 (18.3) compared with 2018 (24.0) and 2019 (22.7) (P < 0.05). Incidence rates of lower extremity muscle injuries (6.04), anterior cruciate ligament (ACL) injuries (0.17), and concussions (0.49) were also higher in 2020 compared with 2018 (2.5, 0.07, 0.27) and 2019 (2.36, 0.05, 0.22) (P < 0.05). More injured players in 2020 missed >90 days (17.7%) than in 2018 (10.2%) and 2019 (10.1%) (P < 0.05). Incidence of all non-COVID-19 illness was higher in 2020 (3.93) than 2018 (1.53) and 2019 (1.32) (P < 0.05). During 2020, there were significant increases in incidence rates of overall injuries, training injuries, lower extremity muscular injuries, ACL injuries, concussions, and non-COVID illness, along with a higher percentage of players missing >90 days compared with the 2 previous seasons. These results may help clarify the effects of future MLS inseason work stoppages and periods of restricted training.

The effect of a 10-week TOCA Football System intervention program on sport-specific motor skills among junior footballers.

The objective of our study was to examine, in addition to using the TOCA Football System tool and training method, the effect of a 10-week intervention on elite youth athletes in terms of their sport-specific motor skills and anthropometric variables. The study covered a group of 32 young players practicing football (U14) (13.45 ± 0.64 years). The junior U14 footballers were randomly assigned to an intervention or TOCA group (TG, N = 15, 13.25 ± 0.58 years) and a control group (CG, N = 17, 13.63 ± 0.66 years). Before starting the test, we performed full anthropometric measurements and assessed the sample's agility with and without the ball and their sport-specific endurance. The measurements were then repeated after the 10-week intervention. Within-group analysis showed significant improvements in muscle mass (p < 0.001), sport-specific endurance (p < 0.001), (p < 0.004) and agility (in TG) both with and without the ball (p = 0.002), (p = 0.004) however, we did not find a significant change in body fat percentage in either group (p = 0.988, p = 0.288). In the CG, "agility with the ball" changed significantly only (p = 0.023). In the between-group analysis with a repeated-measures analysis of variance (mixed-design ANOVA), there was no significant interaction in any performance variables. The main findings of this study indicate that a TOCA Football training program in addition to normal training during the in-season period does not produce additional effects in anthropometric factors, sport-specific endurance and agility performance with the ball (dribbling) and without the ball in comparison with the control condition. From a practical point of view, the presented anthropometric and physical profiles of players can be useful for football coaches in optimizing soccer training. Overall, it also can be concluded that the device can be safely used in the sensitive age group in terms of the development of motor skills since we did not find any negative effects during the use of the device in terms of the parameters we examined. In addition to the expansion of the number of elements and the inclusion of other age groups, it is advisable to carry out further complex tests, as the TOCA Football System offers many research opportunities.

Effects of Four Weeks of In-Season Pre-Workout Supplementation on Performance, Body Composition, Muscle Damage, and Health-Related Markers in Basketball Players: A Randomized Controlled Study.

This randomized, double-blinded, experimental study investigated the effects of a four-week daily pre-workout supplementation (200 mg caffeine, 3.3 g creatine monohydrate, 3.2 g β-alanine, 6 g citrulline malate, and 5 g BCAA) vs. placebo (isocaloric maltodextrin) on anaerobic (jumping, sprinting, agility, and the running-based anaerobic sprint test: RAST) and aerobic (Yo-Yo intermittent recovery test level 1) performance, as well as on body composition and selective muscle damage/health-related blood markers in well-trained basketball players during the in-season period. Eighteen basketball players (age: 24.4 ± 6.3 years, height: 185.7 ± 8.0 cm, weight: 85.7 ± 12.8 kg, body fat: 16.5 ± 4.2%) were randomly assigned into two groups: pre-workout supplement (PWS, n = 10) or placebo (PL, n = 8). PWS consumption increased aerobic performance (PWS: 8 ± 6%; PL: -2 ± 6%; p = 0.004) compared to PL. A significant decrease was observed in peak (F = 7.0; p = 0.017), average (F = 10.7; p = 0.005), and minimum power (F = 5.1; p = 0.039) following 4 weeks of supplementation in both groups. No other significant changes were observed between groups (p > 0.05). In conclusion, the consumption of the current PWS over a four-week period appears to positively influence the aerobic performance of well-trained basketball players during the in-season period. However, it does not appear to mitigate the observed decline in anaerobic power, nor does it affect performance in jumping, sprinting, and agility, or alter body composition or selective muscle damage/health-related blood markers.

In-Season Training Load Variation - Heart Rate Recovery, Perceived Recovery Status, and Performance in Elite Male Water Polo Players: A Pilot Study.

Increased training and competition demands of the in-season period may disturb athlete fatigue and recovery balance. The aim of this study was to describe the training load distribution applied in a competitive period and the training adaptations and fatigue/recovery status of elite water polo players. Effective workload management during tapering (TAP) would restore player recovery and enhance performance. Case series. Level 4. Training load, perceived recovery, maximal speed in 100- and 200-meter swim, heart rate (HR) during submaximal swimming (HRsubmax) and HR recovery (HRR) were assessed in 7 outfield water polo players a week before starting a normal training microcycle (NM), after NM, and after congested (CON) and TAP training blocks in the lead-up to the Final Eight of the European Champions League. Training load was higher in NM compared with CON and TAP by 28.9 ± 2.6% and 42.8 ± 2.1% (P < 0.01, d = 11.54, and d = 13.45, respectively) and higher in CON than TAP by 19.4 ± 4.2% (P < 0.01, d = 3.78). Perceived recovery was lower in CON compared with NM and TAP (P < 0.01, d = 1.26 and d = 3.11, respectively) but not different between NM and TAP (P = 0.13, d = 0.62). Both 100- and 200-meter swim performance was improved in TAP compared with baseline (P < 0.01, d = 1.34 and d = 1.12, respectively). No differences were detected among other training blocks. HRsubmax and most HRR were similar among the training periods. Effective management of training load at TAP can restore recovery and improve swimming performance without affecting HR responses. Despite lower workloads, CON training impairs perceived recovery without affecting performance; however, a short-term training load reduction after a CON fixture restores recovery and improves performance.

Effect of pre-season and in-season training on anthropometric variables, somatotype, body composition and body proportion in elite basketball players

The aims of the study were: 1) to evaluate the changes in anthropometric variables, body composition, somatotype and body proportions of elite basketball players throughout the pre-season period; 2) to evaluate the changes in anthropometric variables, body composition, somatotype and body proportions of elite basketball players throughout the in-season period; and 3) to observe if the age and position influenced the variables analyzed. A total of 17 players belonging to the men’s ACB league team competing in the Euroleague (age = 23.42 ± 5.28 years-old) participated in the study. The players underwent an anthropometric measurement before and after the pre-season, as well as four evaluations throughout the in-season. Anthropometric indices, somatotype components according to Heath and Carter, and adiposity were calculated. The results show that during the pre-season, body mass, BMI, sum of 6 and 8 skinfolds, waist/hip ratio, adipose tissue (kg), adipose tissue percentage, and endomorphy decreased, while ectomorphy increased. However, no significant changes were found in the variables analyzed throughout the season; except for endomorphy, which increased along the in-season. Playing position and age did not have a significant influence on the changes in the anthropometric variables throughout the pre-season and the in-season. In conclusion, while changes in the anthropometric variables in the pre-season were observed, these remained the same during the in-season.

The Relationship Between Maximum Lower Limb Strength &amp; Power, and GPS Acceleration Speed in Elite U20 Gaelic Football Athletes

Previous research indicates positive relationships between high levels of lower limb strength and power, and acceleration sprint velocity in team sport athletes. This cross-sectional study aimed to investigate the relationship between lower limb absolute and relative strength, countermovement jump (CMJ) height, and Global Positioning System (GPS) recorded 20m acceleration sprint velocity in elite male U-20 Gaelic football athletes. Nineteen athletes (19.0 ± 0.5 years; 81.1 ± 5.5 kg; 182 ± 6.2 cm) from the same elite U-20 squad participated in this study during an in-season period. Subjects performed a &gt;95% 1RM box squat, a 20m sprint test, and a CMJ test. Relative maximum lower limb strength (r = 0.54, 95% CI [0.11 to 0.8]; p &lt; 0.05) and CMJ height (r = 0.66, 95% CI [0.29 to 0.86]; p &lt; 0.001) showed strong correlations with 20m sprint velocity. A multiple linear regression analysis demonstrated that lower limb maximum relative strength and CMJ height significantly predicted 20m sprint velocity (Adjusted R2 = 0.51, F (2, 16) = 6.29, p &lt; 0.05). These findings provide evidence for the importance of elite under-age Gaelic football athletes acquiring high levels of lower limb strength and power characteristics to enhance acceleration sprint performance.

External Workload Evolution and Comparison across a Pre-Season in Belgian Professional Football Players: A Pilot Study

The pre-season plays a crucial role in the preparation of professional football players, as it allows for an extensive focus on training sessions compared to the more congested schedules during the in-season period, especially in professional football leagues. This study aimed to describe the workload during a 6-week pre-season in Belgian professional football players and to analyse and compare the workloads for players in each microcycle according to several variables of external workload (e.g., distance covered at some velocities). Seventeen male Belgian professional football players competing in the second division of the Belgian league system participated in the study. Throughout the 6 weeks, the players were closely monitored during both training sessions and friendly matches using Global Positioning System (GPS) devices. Several parameters, including total distance covered and distance at different velocities, were recorded. Accelerating and decelerating distances, as well as the number of sprints, were also captured. Statistical analysis was based on a repeated measures ANOVA, percentage dynamics, and effect size calculations. The results obtained showed a progressive increase in the distance travelled at different intensities from week 1 (i.e., lower values) to week 3 (i.e., higher values), with reductions in these values in week 6, prior to the start of the official competition. Similarly, the peak of accelerations and decelerations were observed in week 2 and week 3, with decrements at the end of the pre-season period. This comprehensive investigation attempts to shed light on the effects and dynamic changes in external workload during the crucial pre-season, contributing valuable insights for coaches and practitioners in football conditioning and training programs, especially concerning optimal preparation for the beginning of the league’s season.

The Ratio between Weekly Training and Match External Physical Loads in U17 Elite Youth Soccer Players: Implications for the Training Process.

Research on the external physical load on elite youth soccer players during the weekly training microcycle in competitive periods and official matches is limited. The aims of this study were twofold: a) investigate possible differences in external physical load (PL) across player positions in U17 elite youth soccer players during official matches; b) determine the weekly training to match physical load ratio (WTMLr) across player positions. The sample included 20 outfield players from an elite soccer academy (mean age 15.94 ± 0.25 years) playing in four positions: central defender (CD), full-back (FB), central midfielder (CM) and Striker (S). Data were collected during the spring in-season period for 17 official matches played in a 4-3-3 game format. Indicators of external physical load monitored were: total distance (TD); total distance in high-speed running (HSR; > 16.1 km.h-1); total distance in sprint running (SPR; > 21.6 km.h-1); and relative physical load intensity (%HSR). The WTMLr was calculated for TD, HSR, SPR and %HSR as the ratio of the average weekly sum of training PL to the average sum of PL in an official match for a given players' position. Collectively, the training intensity during a one-week microcycle (%HSR in WTMLr) achieved only 76 % of match demands. CD performed significantly lower in all measured indicators of external PL during the official match than all other positions (p < 0.05; g > 0.80) except for TD in S. S achieved significantly higher SPR during official matches compared to CD (p < 0.05; g > 0.80), CM, and FB (g > 0.80). In contrast, CD reported higher WTMLr (medium-large effect size) in HSR and SPR indicators than all other positions. CM performed significantly higher %HSR in WTMLr than S and FB (p < 0.05; g > 0.80). Results revealed insufficient training intensity relative to match demands and, at the same time, weekly training PL did not meet match demands (especially in HSR and SPR) for players across the different positions. Therefore, practitioners should select appropriate training methods (drills and games) to ensure sufficient training intensity (HSR and SR metrics) and consider using the WTMLr, which can be used to help optimise and individualise training PL for different player positions.

Effects of plyometric jump training on measures of physical fitness and lower-limb asymmetries in prepubertal male soccer players: a randomized controlled trial

BackgroundHigh level of physical fitness is a paramount soccer performance factor. As such, developing key components of physical fitness such as sprinting, jumping, and change of direction (CoD) at an early age empowers both short- and long-term performance success. Although previous research in prepubertal male soccer players has reported physical fitness performance enhancements following plyometric jump training (PJT), the effects on inter-limb asymmetries remain unclear.ObjectiveTo assess the effects of PJT on measures of physical fitness and inter-limb asymmetries in prepubertal male soccer players.MethodsA total of 27 participants were recruited, and randomly assigned to either a PJT group (n = 13; age = 12.7 ± 0.2 years; maturity offset = -1.6 ± 0.7) or an active control group (CG) (n = 14; age = 11.8 ± 0.4 years; maturity offset = -2.51 ± 0.61). The training intervention lasted eight-week and was conducted during the in-season period, with twice-weekly sessions. Physical fitness tests were conducted before and after the intervention, including the 505 change-of-direction (CoD; [505 CoD test]), countermovement-jump (CMJ) height, standing-long-jump (SLJ) distance, and single-leg hop test for distance with dominant (SHTD-D) and non-dominant legs (SHTD-ND). A jump-based asymmetry score was calculated as the difference between HTD and HTND.ResultsANCOVA analysis revealed significant between-group differences in all physical fitness measures at post-test. Specifically, the PJT group showed significant large improvements in CMJ height, SLJ distance, HTD and HTND, and CoD speed (d = 0.84 to 2.00; ∆1.05% to 16.85%). Moreover, the PJT group showed a significant, small reduction in the inter-limb asymmetry score (d = 0.43; ∆-45.21%). In contrast, no significant changes were reported in the CG between pre-and post-tests (d = 0.07 to 0.24; ∆0.21% to 0.98%).ConclusionsThe incorporation of PJT into the training schedules of prepubertal male soccer players resulted in positive effects on various measures of physical fitness. Furthermore, our findings suggest that PJT can reduce lower-limb asymmetry, which could potentially decrease the risk of lower limb injuries.Trial registrationThis study does not report results related to healthcare interventions using human participants and therefore it was not prospectively registered.

Individualized monitoring of longitudinal heading exposure in soccer

There is growing concern that repetitive soccer headers may have negative long-term consequences on brain health. However, inconsistent and low-quality heading exposure measurements limit past investigations of this effect. Here we conducted a comprehensive heading exposure analysis across all players on a university women’s soccer team for over two calendar years (36 unique athletes), quantifying both game and practice exposure during all in-season and off-season periods, with over ten thousand video-confirmed headers. Despite an average of approximately 2 headers per day, players’ daily exposures ranged from 0 to 45 headers, accumulating to highly variable total exposure of 2–223 headers over each in-season/off-season period. Overall, practices and off-season periods accounted for 70% and 45% of headers, respectively. Impact sensor data showed that heading kinematics fell within a tight distribution, but sensors could not capture full heading exposure due to factors such as compliance. With first-of-its-kind complete heading exposure data, we recommend exposure assessments be made on an individual level and include practice/off-season collection in addition to games and competitive seasons. Commonly used group statistics do not capture highly variable exposures, and individualized complete heading exposure tracking needs to be incorporated in future study designs for confirming the potential brain injury risk associated with soccer heading.

Dose-Response Relationship for External Workload and Neuromsuclar Performance Over a Female, Collegiate, Basketball Season.

Philipp, NM, Cabarkapa, D, Blackburn, SD, and Fry, AC. Dose-response relationship for external workload and neuromsuclar performance over a female, collegiate, basketball season. J Strength Cond Res 38(5): e253-e263, 2024-The aim of this study was to investigate the relationship between external workload exposure and changes in countermovement jump force-time characteristics over the course of an entire basketball season, in a sample of National Collegiate Athletic Association Division I, female, basketball players. Data for 12 players were retrospectively analyzed, with external workload being quantified by means of an exponentially weighted, acute, and chronic workload, as well as an acute:chronic workload ratio derived from an inertial measurement unit-based system worn by athletes for all practices and games during the regular season. Countermovement jumps were performed on a total of 26 test days over the span of the in-season competitive period. To statistically analyze these relationships, and to account for multiple observations of the same athletes in a data set, linear mixed-effects models with athlete identity (ID) intercept as the random effect were used. Study findings suggested that associations between external workload exposure and respective force-time characteristics after controlling for the random effect of athlete ID were dependent on the specific metric or metric subgroup used, as well as the type of workload exposure (e.g., acute vs. chronic). Force-time signatures from the braking phase (e.g., average braking force) seemed to be particularly associated with higher degrees of acute workload exposure, whereas strategy-based metrics such as countermovement depth showed significant associations with chronic workload exposure. Furthermore, model results suggested the importance of analyzing neuromuscular responses to external workload on an individual basis, rather than across an entire team. Findings might help practitioners in their selection process related to metrics of interest in monitoring neuromuscular fatigue and readiness.

Physical Conditioning and Functional Injury-Screening Profile of Elite Female Soccer Players: A Systematic Review.

To identify the physical conditioning and functional injury-screening characteristics of elite female soccer players. This review was prospectively registered (PROSPERO CRD4202346765). Searches were conducted in PubMed/MEDLINE, Cochrane Library, Scopus, and Web of Science (from inception in March 2023 to July 2023). Updated searches were conducted in October 2023 and April 2024. Included studies were quantitative studies conducted on female soccer players. Main outcomes were functional and physical profiles. Screening, data extraction, and quality assessment (Quality Assessment Tool for Quantitative Studies and the Oxford Levels of Evidence scales) were performed. Mean differences between preseason and in-season testing periods were estimated by Hedges g effect size. Methods and results were reported according to PRISMA guidelines. The search yielded 1727 articles, of which 10 were included. Overall methodological quality of the studies was strong, with amoderate level of evidence. Players exhibited mean maximal oxygen uptake of 52.6 (4.5)mL·min-1·kg-1, 20-m linear-sprint performance of 3.58 (0.18)seconds, countermovement jump of 31.0 (2.9)cm, unilateral countermovement jump of 14.4 (2.1)cm, and quadriceps and hamstring peak torque at 60°·s-1 of 133 (23) and 87 (17)N·m, respectively. Mean scores recorded during in-season were 2% to 22% better than in preseason (effect size: small to very large). This review provides valuable normative physical conditioning and functional injury-risk assessment data for elite female soccer players. Coaches and conditioning staff can use these insights to interpret their own records and optimize their training processes. Furthermore, this study identifies methodological limitations to address in future research.

Application of arbitrary and individualized load quantification strategies over the weekly microcycle in professional soccer players.

The aims of this study were to: (a) determine the differences in external load quantification between arbitrary and individual speed thresholds over the weekly microcycle in professional soccer players, and (b) analyse the association between internal load and different external load quantification strategies (ELQSs). Ten professional outfield players were monitored during training sessions and official matches using 10 Hz GPS devices over a 6-week in-season period. The absolute and relative ("R" before the distance category) distances covered were calculated for the following external load variables: medium-intensity running distance (MIR), high-intensity running (HIR), sprint distance (SD), and very high-intensity running (VHIR). Individualized thresholds were determined based on maximal sprinting speed (MSS) and the last speed achieved during the 30-15 Intermittent Fitness Test (VIFT) of each player. In terms of match-day workload, significant differences (p < 0.05) were observed between arbitrary and individualized strategies (i.e., MSS and VIFT) for the distance covered in MIR, HIR, SD, VHIR, RHIR, RSD, and RVHIR. The MSS strategy compared to arbitrary thresholds revealed significant differences (p < 0.05) for distance covered in HIR, RHIR, and VHIR during all training sessions. The present results showed that arbitrary thresholds lead to underestimation of external load absolute and relative metrics compared to the MSS strategy throughout the microcycle. The VIFT strategy mainly revealed differences in external load quantification regarding MD compared to arbitrary thresholds. Individualized speed threshold strategies did not achieve better associations with internal load measures in comparison with arbitrary thresholds in professional soccer players.