Beyond the Jump: A Scoping Review of External Training Load Metrics in Volleyball.

CONTEXT: Volleyball is a complex sport involving multifaceted movements and high-velocity actions, leading to diverse external training loads (ETLs) that have profound implications for player performance and injury risk. OBJECTIVE: To provide a comprehensive overview of the measurement of ETL in volleyball, identify gaps in current understanding, and offer valuable insights for stakeholders in the field. DATA SOURCES: The literature search was conducted across the following electronic databases: PubMed/Medline, Scopus, Web of Science, and SPORTDiscus. STUDY SELECTION: Studies were selected based on their relevance to the measurement of ETL in volleyball. STUDY DESIGN: A scoping review methodology was chosen to map and summarize the broad body of literature related to ETL measurement in volleyball. LEVEL OF EVIDENCE: Level 4. DATA EXTRACTION: Data related to ETL measurements in volleyball were extracted and analyzed from the selected studies, focusing on metrics utilized, player positions examined, and technologies employed. RESULTS: A total of 18 studies related to ETL in volleyball were identified and examined for this review. Despite the importance of sagittal plane movements in volleyball, the review identified a substantial research gap regarding ETL measurements beyond this plane, as well as a lack of focus on the unique demands of different player positions like the liberos. The use of technologies such as inertial measurement units was prevalent, but more comprehensive measurement methods are needed. CONCLUSION: There is a critical need for diversified ETL metrics in volleyball, extending beyond the conventional sagittal plane measurements. The findings highlight a substantial research gap in addressing the unique demands of different player positions, notably the liberos. This study underscores the importance of incorporating multiplanar movement data, player-specific roles, and advanced measurement technologies to develop more tailored training programs and injury prevention strategies.

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.

Intra-Session Reliability of Sprint Performance on a Non-Motorised Treadmill for Healthy Active Males and Females.

This study examined the intra-session reliability of sprint performance on a non-motorized treadmill amongst healthy, active male and female adults. One hundred and twenty participants (males n = 77; females n = 45) completed two familiarization sessions, followed by a third session that consisted of three trials (T1, T2, T3) of maximal sprints (4-s), interspersed by three minutes of recovery. Combining males and females exhibited moderate-to-excellent test-retest reliability (intra-class correlation coefficient, ICC), minimal measurement error (coefficient of variation, CV) and trivial differences between trials (effect size, ES) for speed, power, total work and acceleration (ICC = 0.82-0.98, CV = 1.31-8.45%, ES = 0.01-0.22). The measurement error was improved between comparisons of T1 vs. T2 (CV = 1.62-8.45%, ES = 0.12-0.22) to T2 vs. T3 (CV = 1.31-6.56%, ES = 0.01-0.07) and better for females (CV = 1.26-7.94%, ES = 0.001-0.26) than males (CV = 1.33-8.53%, ES = 0.06-0.31). The current study demonstrated moderate-to-excellent reliability and good-moderate measurement error during a 4-s sprint on a non-motorized treadmill. However, sex had a substantial impact with females exhibiting better values. Practitioners should employ at least two separate trials within a session, in addition to multiple familiarization sessions, to achieve reliable non-motorized treadmill sprint performances.

Monitoring Training Loads in Judo Athletes: Different Time Courses of Physiological, Neuromuscular, and Perceptual Responses.

This study aims to elucidate the internal load, performance, physiological, and perceptual recovery responses during four weeks of traditional judo training. Ten cadet and junior judo athletes were evaluated daily for four weeks, in which their perception of recovery, heart rate variability, handgrip strength, and countermovement jump performance were assessed. A one-way repeated-measures ANOVA was performed to analyze the variables across the weeks. A significant time effect in internal load (F = 6.51; p = 0.001) has been observed. Handgrip test performance showed significantly higher values in the 3rd and 4th weeks (p <0.001), while countermovement jump performance was significantly higher in the 4th week (p =0.0007). The heart rate variability's coefficient of variation was lower in both the 3rd and 4th weeks (p =0.02). Regarding perceptual aspects, the Hooper Index showed a significant time effect (p =0.04), but pairwise comparison did not reveal differences between weeks. The present study indicates that neuromuscular, physiological, and perceptual responses to training load alterations present different time courses. This must be considered for the adequate monitoring of training programs.

Crucial workload variables in female-male elite Brazilian Beach Handball: An exploratory factor analysis.

This study aimed to identify the most important variables of male and female beach handball workload demands and compare them by sex. A total of 92 elite Brazilian beach handball players (54 male: age 22.1 ± 2.6 years, height 1.8 ± 0.5 m, weight 77.6 ± 13.4 kg; and 38 female: age 24.4 ± 5.5 years, height 1.7 ± 0.5 m, weight 67.5 ± 6.5 kg) were analyzed in 24 official matches during a four-day congested tournament. From 250 variables measured by the inertial measurement unit, fourteen were extracted for analysis using Principal Component Analysis as selection criteria. Five Principal Components (PC) were extracted that explained 81.2-82.8% of total variance (overview of workload demands during beach handball). Specifically, 36.2-39.3% was explained by PC1 (DistanceExpl, Distance, Distance4-7 km/h, and Acc), 15-18% by PC2 (AccMax, Acc3-4 m/s, Dec4-3 m/s), 10.7-12.9% by PC3 (JumpsAvg Take-Off, JumpsAvg Landing and PLRT), 8-9.4% by PC4 (Distance> 18.1 km/h, SpeedMax), and 6.7-7.7% by PC5 (HRAvg and Step Balance). Sex-related differences were found in the PC distribution of variables, as well as in selected variables (HRAvg, Dec4-3 m/s, Acc3-4 m/s, JumpsAvg Take-Off, JumpsAvg Landing, AccMax, Distance, Distance4-7 km/h, Acc, SpeedMax) with higher values in male players (p < .05). In conclusion, the sex-related PC distribution and workload demands in beach handball should consider for training design and injury prevention programs.

Effects of a Short-Term Detraining Period on the Strength Deficit and Functional Performance of Highly Trained Soccer Players.

ABSTRACT: Loturco, I, Grazioli, R, Veeck, F, Nakamura, FY, Inácio, M, Schons, P, Preissler, A, Pinto, RS, Pereira, LA, McGuigan, MR, and Cadore, EL. Effects of a short-term detraining period on the strength deficit and functional performance of highly trained soccer players. J Strength Cond Res 37(10): 2058-2063, 2023-The aim of this study was to examine the effects of a 4-week detraining period on the neuromuscular performance of highly trained soccer players. Pre and post detraining, 18 adult soccer players (age: 27 ± 4.9 years; height: 180.2 ± 7.1 cm; body mass [BM]: 78.9 ± 7.6 kg) performed vertical jumps, 20-m linear sprints, curve sprint and change of direction speed tests, and a progressive loading test in the half-squat exercise with loads corresponding to 50, 100, and 150% of the players' BM to assess the peak-force (PF), mean power (MP), and strength-deficit (SDef). Pre and post differences in the variables of interest were analyzed using paired t -tests and effect sizes (ES). No significant changes were detected for vertical jumping height and sprint times. Higher PF at 50 and 100% BM and lower SDef were shown when comparing pre- and postassessments (ES = 0.66, 0.68, 0.55; p = 0.018, 0.016, and 0.046, respectively). The MP at 50 and 100% BM increased significantly after the detraining phase (ES = 0.56, 0.82; p = 0.049 and 0.007, respectively). The results indicate that these athletes were able to maintain and achieve satisfactory levels of performance after a short period of training cessation. Interestingly, some strength- and power-derived parameters improved significantly after short-term detraining, which may have important implications for training programs aimed at maximizing speed and power performance. It is recommended that coaches test their players not only at the beginning but also at the end of the season, to better evaluate variations in performance and thus create more efficient and tailored training strategies.

Intraindividual Relationships Between Training Loads and Heart-Rate Variability in High-Level Female Futsal Players: A Longitudinal Study.

PURPOSE: To investigate the internal training loads of a professional Spanish female futsal team throughout 26 weeks of training including preseason and in-season weeks and verify the impact of training period and/or training load magnitudes on heart-rate variability responses. Furthermore, we aimed to assess, intraindividually, the relationship between training load and the coefficient of variation (CV) of weekly natural log of the root mean square difference of successive normal interbeat (RR) intervals (lnRMSSDCV), obtained from ∼5 measures per week, and recorded in the seated position. METHODS: A within-subject design involved 12 high-level outfield female futsal players (mean [SD] age: 23.9 [3.4] y). RESULTS: lnRMSSD was significantly lower and lnRMSSDCV was significantly higher during the preseason (weeks 1-6) compared to in-season (weeks 7-26) (P < .001). Individually, players presented moderate to large negative correlations between lnRMSSDCV and lnRMSSD during the 26 weeks of observation. Correlations ranged between rplayer4 = -.41 (95% CI, -.69 to -.02) and rplayer12 = -.55 (-.78 to -.18). Players also presented moderate to very large positive correlations between lnRMSSDCV and session rating of perceived exertion. Correlations ranged between rplayer7 = .41 (.04 to .71) and rplayer1 = .71 (.45 to .86). CONCLUSION: Professional female futsal players in this study presented increased lnRMSSD and reduced lnRMSSDCV during 20 weeks into the competitive season compared to 6 weeks of preseason. Furthermore, lnRMSSDCV was negatively associated with lnRMSSD on an intraindividual basis. Finally, higher internal training loads were positively correlated with lnRMSSDCV, indicating that heart-rate variability is responsive to weekly training loads.

Comparing Sleep in Shared and Individual Rooms During Training Camps in Elite Youth Soccer Players: A Short Report.

CONTEXT: Athletes' sleep is the most important recovery strategy and has received growing attention. However, athletes may experience sleep disruptions due to numerous factors, such as training and competition workloads, travel, changes in sleep-wake schedules, and sleeping environments. They often spend nights in unfamiliar hotels, and sharing a bed, room, or both with another person might affect sleep duration and quality. OBJECTIVE: To analyze the effect of sleeping in shared (SRs) versus individual (IRs) rooms on objective and subjective sleep and on slow-wave-sleep-derived cardiac autonomic activity during an official training camp in elite youth soccer players. Training and match workloads were characterized. DESIGN: Observational case study. SETTING: Hotel accommodations. PATIENTS OR OTHER PARTICIPANTS: Thirteen elite male youth soccer players. RESULTS: Players slept longer in IRs than in SRs (+1:28 [95% CI = 1:18, 1:42] hours:minutes; P < .001). Sleep efficiency was higher in IRs than in SRs (+12% [95% CI = 10%, 15%]; P < .001), whereas sleep latency was shorter in IRs than in SRs (-3 [95% CI = -15, -4] minutes; P < .001). Subjective sleep quality was lower in IRs than in SRs (-2 [-3 to -2] arbitrary units; P < .001). No differences were found for slow-wave-sleep-derived cardiac autonomic activity or for training or match workloads between training camps. CONCLUSIONS: During soccer training camps, sleep may be affected by whether the athlete is in an SR versus an IR.

On-Court Change of Direction Test: an Effective Approach To Assess COD Performance in Badminton Players.

The aim of this research was to assess the reliability of a specific change of direction test (i.e., "On-Court COD test") in youth badminton players, evaluate the effect of age on On-Court COD performance, and examine its correlations with linear speed, change of direction speed, and vertical jump tests. Forty-two young badminton players (27 males and 15 females; age: 17.3±1.6 years, body height: 170.3±7.5 cm, body mass: 59.0±9.7 kg) were divided into two age groups (Under 17 years and under 19 years). Tests included: linear sprints (5, 10, and 20-m), bilateral/unilateral countermovement jumps, a hexagon test, traditional and modified 505 change of direction tests; and On-court COD. Results showed an excellent intraclass correlation coefficient score (0.90) and a very low coefficient of variation values (1.6%) for the On-Court COD test. Comparing age groups, under 19 players were significantly faster in linear sprints (i.e., 5, 15 and 20-m; small to moderate effect sizes) and in all change of direction tests (moderate to large effect sizes). Moreover, the On-Court COD test showed moderate to large (r=.513-.779) relationships with both acceleration and COD abilities in under 17 players, and with linear sprints, COD, and jump performances in under 19 players. These data indicate that the On-Court COD test is a useful and reliable means to assess COD performance in youth badminton players and it is associated with acceleration, sprint and jump performance.

Squat and countermovement jump performance across a range of loads: a comparison between Smith machine and free weight execution modes in elite sprinters.

The aims of this study were to: 1) provide and compare the height achieved during Smith machine (SM) and free weight (FW) loaded jumps executed over a wide spectrum of loads (40-120% of body mass [BM]); and 2) test the difference between loaded and unloaded squat jump (SJ) and countermovement jump (CMJ) attempts in ten highly trained male sprinters. On the first visit, athletes performed unloaded SJ and CMJ, loaded SJ with loads corresponding to 40, 60, 80, 100, and 120% BM, and loaded CMJ at 100% BM using an Olympic barbell (FW). On the second visit, they performed loaded SJ and CMJ tests under the same loading conditions on the SM device and, subsequently, a half-squat one-repetition maximum (1RM) assessment. The relative strength (RS = 1RM/BM) of the athletes was 2.54 ± 0.15. Loaded SJ performance was similar between SM and FW, and across all loading conditions. Differences in favour of CMJ (higher jump heights compared with SJ) were superior in the unloaded condition but decreased progressively as a function of loading. In summary, sprinters achieved similar SJ heights across a comprehensive range of loads, regardless of the execution mode (FW or SM). The positive effect of the countermovement on jump performance is progressively reduced with increasing load.

Season Match Loads of a Portuguese Under-23 Soccer Team: Differences between Different Starting Statuses throughout the Season and Specific Periods within the Season Using Global Positioning Systems.

This study aimed to quantify the external match loads (EMLs) of a Portuguese u-23 soccer team, competing at the highest national level for the age group, comparing players with different starting status throughout a competitive season and specific blocks. Thirty-five outfield soccer players were split into three groups for the entire season analysis and for each 3-month block, based on the percentage of games played as a starter. The three groups consisted of "starters" (≥55% of the games as a starter), "fringe" (30−54%), and "non-starters" (<30%). EMLs were recorded using 10 Hz GPS technology throughout the whole season (26 matches). Differences (p < 0.05) were found for total distance (TD), exposure time, and the number of accelerations and decelerations between starters and non-starters throughout the season (d = 0.73 to 1.08), and within each block (d = 0.59 to 1.68). Differences were also found between starters and fringe players for the number of accelerations in Block 2 (p = 0.03; d = 0.69), and TD (p = 0.006; d = 1) and exposure time (p = 0.006; d = 0.95) in Block 3. Differences in the EML were almost always accompanied by large differences in game time. Our results highlight the differences in the EML of starters and non-starters, emphasizing the need for compensatory training, especially with players that obtain significantly less playing time, to prepare the players for match demands (e.g., high-intensity efforts such as sprinting, accelerations, and decelerations).

Effect of Competitive Status and Experience on Heart Rate Variability Profiles in Collegiate Sprint-Swimmers.

ABSTRACT: Flatt, AA, Hornikel, B, Nakamura, FY, and Esco, MR. Effect of competitive status and experience on heart rate variability profiles in collegiate sprint-swimmers. J Strength Cond Res 36(10): 2898-2904, 2022-Interindividual differences in training history may be a determinant of heart rate variability (HRV) profiles in collegiate sprint-swimmers and may account for differences observed between elite and subelite athletes. We therefore compared HRV profiles among national-level and conference-level sprint-swimmers while accounting for individual swim-training history. Twenty-eight short-distance swimmers (18 men and 10 women) recorded postwaking HRV throughout a 4-week standardized training period. The 4-week mean (M) and coefficient of variation (CV, a marker of daily fluctuation) were calculated for resting heart rate (RHR) and the natural logarithm of the root mean square of successive differences (LnRMSSD). Swimmers were categorized as national-level (n = 12) or conference-level (n = 16) competitors. Years of competitive experience was documented for each individual to index training history. p < 0.05 was considered statistically significant. No sex-related differences were observed for any variables (p > 0.05). LnRMSSDM (effect size [ES] = 0.95), LnRMSSDCV (ES = -1.18), RHRCV (ES = -1.05), and competitive experience (ES = 1.23) differed between status groups (p < 0.05). Accounting for multicollinearity between competitive experience and LnRMSSD variables (p < 0.05), competitive experience remained associated with LnRMSSDM (r = 0.44, p = 0.02). With competitive experience included as a covariate, differences in LnRMSSDM between status groups disappeared (p > 0.05, ES = 0.31). National-level swimmers exhibit higher and more stable LnRMSSD than that of their conference-level teammates throughout standardized training. Differences in trend characteristics were attributed to training age. This information may assist practitioners with interpreting interindividual differences in HRV profiles throughout training periods among a mixed roster of athletes.

Monitoring Heart Rate Variability and Perceived Well-Being in Brazilian Elite Beach Volleyball Players: A Single-Tournament Pilot Study.

ABSTRACT: Nakamura, FY, Torres, VBC, da Silva, LS, Gantois, P, Andrade, AD, Ribeiro, ALB, Brasileiro-Santos, MdS, and Batista, GR. Monitoring heart rate variability and perceived well-being in Brazilian elite beach volleyball players: A single-tournament pilot study. J Strength Cond Res 36(6): 1708-1714, 2022-The aim of this study was to monitor the changes in heart rate variability (HRV) and perceptual well-being status after a beach volleyball (BV) tournament day in high-level U17 and senior players. Seventeen BV players (U17 [15-16 years]: n = 08; and senior [19-41 years]: n = 09) competing at national and/or international BV level participated in this study. Resting HRV and perceptual well-being measures were recorded across 4 moments: night 1 (prematches night), morning 1 (prematches morning), night 2 (postmatches night), and morning 2 (postmatches morning). Session rating of perceived exertion was assessed 10 minutes after each match, and accumulated match loads were used for analysis. Senior players presented higher values of natural logarithm of square root of the mean squared differences of successive RR intervals (lnRMSSD) at the 4 observation moments than U17 players (p = 0.006). Within-subjects analysis showed a larger mean difference regarding both lnRMSSD and natural logarithm SD of normal R-R intervals (lnSDNN) between night 1 vs. night 2 in U17 players (effect size = 1.11 and, 0.96, respectively) compared with senior (effect size = 0.40 and 0.32, respectively). Accumulated match loads were negatively correlated with percentage change in lnRMSSD (r = -0.54; p = 0.037). U17 players showed higher well-being variation than senior (group × time; p = 0.02). In conclusion, the lnRMSSD index was able to discriminate the U17 and senior BV players, and maintaining high vagally related HRV indices is an important response to BV training and competition.

How does curve sprint evolve across different age categories in soccer players?

Research has shown that soccer players regularly execute curved sprints during matches. The purpose of this study was to determine the age-related effects on curve sprint (CS) performance to both sides, asymmetry, and association with linear sprint (LS). Eighty-four soccer players (aged 16.1 ± 1.6 categorized in U15, U17, and U20) were recruited, who performed CS and LS tests. One-way analysis of variance (ANOVA) and effect size (ES) were used to compare CS performance between age categories, and relationships between physical performance measures were calculated using Pearson's correlation coefficient. The main findings of this study were that: 1) there were significant differences in the "good" side CS among age groups (p < 0.001; ES from moderate to large), but not in the "weak" side CS, 2) curve asymmetry was significantly higher in U20 than U15 (p < 0.05; ES large) and U17 players (p < 0.05; ES moderate), and 3) relationships between CS and LS times decreased with age (from significant and very large [p < 0.001] to non-significant and smallmoderate [p > 0.05]). This study highlights the importance of assessing and training CS in different age categories, an action that becomes less correlated with LS as age increases, with the aim of mitigating the increase in asymmetries as a result of the specialization process, focusing interventions mainly on improving the CS "weak" side.

Reliability and usefulness of maximum soccer-specific jump test: a valid and cost-effective system to measure on soccer field.

The aims of this study were (a) to assess intra-session reliability and usefulness of the soccer-specific maximum vertical jump (heading test, HT) and (b) to analyse the validity of the easy-to-use and cost-effective instrument (smartphone camera, MOB) compared with gold-standard instrument (3D motion capture system, MOCAP) to obtain the vertical jump performance during HT. Twelve semi-professional high-level and fifteen amateur soccer male players (23.9 ± 3.6 years) performed three HT attempts, and kinematic data were recorded with MOB and MOCAP. Intra-class correlation coefficient (ICC) and coefficient of variation (CV) were used as measures of intra-session reliability. T-test with Cohen's effect size (ES), Pearson's product moment and Bland-Altman analysis were used to obtain MOB validity. Regarding intra-session reliability, the CV was 1.13%, and ICC was 0.98, considered acceptable. Respecting validity criteria did not reveal significant differences (p < 0.05; effect size = 0.06, considered trivial), 'almost perfect' correlation (Pearson) (r = 0.98; p < 0.05), and strong agreement were obtained between MOB and MOCAP. This finding showed a test (HT) with a specific character, using cost-effective instrument and applicable to all soccer fields (adjusted to the standardised lines in the soccer field), all of them backed-up by reliability, usefulness and validity criteria.

Using the Rating of Perceived Exertion and Heart Rate to Quantify Training Intensity in Female Soccer Players: Validity and Utility.

ABSTRACT: Costa, JA, Brito, J, Nakamura, FY, Figueiredo, P, and Rebelo, A. Using the rating of perceived exertion and heart rate to quantify training intensity in female soccer players: validity and utility. J Strength Cond Res 36(1): 201-206, 2022-The aims of this study were as follows: (a) to analyze associations between session rating of perceived exertion (sRPE) and training impulse (TRIMP); (b) to verify whether significantly different ranges of percentage of heart rate peak (%HRpeak) would be reached in each discrete RPE category; and (c) to investigate the amount of time spent >90% of HRpeak and associated intraplayer and interplayer variability during soccer technical training sessions with similar contents and duration. This was a single-group observational study that measured the internal training load during 6 weeks of the competitive period in 17 high-level female soccer players. All training sessions started around 9 pm. and lasted on average 94 ± 5 minutes. During each training session, RPE, sRPE, TRIMP, HRex (%HRpeak), and time spent at >90% of HRpeak were assessed. A very large correlation was found between sRPE and TRIMP (r = 0.78; 95% confidence interval: [0.74-0.82]). Significant differences were observed between %HRpeak associated with each RPE value (i.e., RPE = 2 arbitrary unit [68%; 65-69% of %HRpeak]; RPE 3 [72%; 69-75%]; RPE 4 [79%; 76-82%]; RPE 5 [84; 81-87%]; χ2 = 73.34; df = 3; P < 0.001). Intraplayer and interplayer coefficients of variation for the time spent >90% of HRpeak (∼8% of training time, ∼7 minutes per session) during training sessions were 73 and 92%, respectively. In conclusion, it was confirmed that sRPE and TRIMP displayed good convergent validity, and different %HRpeak were observed for each discrete RPE. However, because of the high variability in the time >90% of HRpeak, careful monitoring of individual exercises should be performed to ensure the desired training stimulus for each player.

Influence of Mental Fatigue on Physical Performance, and Physiological and Perceptual Responses of Judokas Submitted to the Special Judo Fitness Test.

ABSTRACT: Campos, BT, Penna, EM, Rodrigues, JGS, Mendes, TT, Maia-Lima, A, Nakamura, FY, Vieira, ÉLM, Wanner, SP, and Prado, LS. Influence of mental fatigue on physical performance, and physiological and perceptual responses of judokas submitted to the Special Judo Fitness Test. J Strength Cond Res 36(2): 461-468, 2022-Mentally fatigued athletes present impaired aerobic performance, strength endurance, and manual dexterity, despite no changes in anaerobic performance and maximal muscle strength and power. Noteworthy, the effect of mental fatigue on physical performance during high-intensity intermittent tests that require specific motor skills of fighting sports has not been investigated. Therefore, this study aimed to verify whether mental fatigue influences performance and physiological and perceptual responses of judokas subjected to a high-intensity intermittent test designed specifically and validated for judo. Each judoka performed 2 experimental trials-a control trial one and the other one after the induction of mental fatigue. These trials were scheduled in a random and balanced order. In both trials, lactate, glucose, and cortisol concentrations, the heart rate variability, and perceptual variables were collected after the initial treatment and after the Special Judo Fitness Test (SJFT). The initial treatment consisted of a 30-minute cognitive demanding task (Stroop Color test) or watching a movie (control) and was followed by the SJFT. The Stroop Color test increased the perceptions of mental fatigue and effort, without affecting motivation for subsequent testing. Unexpectedly, mentally fatigued athletes did not show reduced performance during the SJFT. Regarding the physiological variables, no significant differences were identified between the 2 experimental conditions. We conclude that physical performance measured during a specific test for judokas is not impaired by a previous 30-minute cognitive task that causes mental fatigue. In addition, this cognitive task did not influence the physiological changes induced by the specific physical test.

The Increased Effectiveness of Resistance Training on Unstable vs. Stable Surfaces on Selected Measures of Physical Performance in Young Male Soccer Players.

ABSTRACT: Sanchez-Sanchez, J, Raya-González, J, Ramirez-Campillo, R, Chaabene, H, Petisco, C, and Nakamura, FY. The increased effectiveness of resistance training on unstable vs. stable surfaces on selected measures of physical performance in young male soccer players. J Strength Cond Res 36(4): 888-894, 2022-To examine the effects of 10-week (2/wk) resistance training on stable vs. unstable surfaces on selected measures of physical performance in young male soccer players, national-level U19 players participated in this study. They were randomly allocated to an unstable resistance training group (uRT, n = 27) or a stable resistance training group (sRT, n = 28). Before and after the training, horizontal jumping with dominant (Hop D) and nondominant leg (Hop non-D), repeated sprint ability (RSA best time [RSAbest] and RSA mean time [RSAmean]), change-of-direction (COD) speed (Illinois COD test), and aerobic endurance (YoYo Intermittent Recovery Test Level 1 [YoYo IR1]) were assessed. To establish the effects of the interventions on the dependent variables, a 2 (group: uRT and sRT) × 2 (time: pre, post) analysis of variance with repeated measures on time was computed. A significant main effect of time was observed for Hop non-D, RSAbest, and RSAmean (p = 0.003-0.06, effect size [ES] = 0.06-0.15). Furthermore, significant group × time interactions were shown for RSAbest (p = 0.007, ES = 0.13) and RSAmean (p = 0.002, ES = 0.2). Post hoc analysis revealed significant pre- to post-training improvements for RSAbest (p = 0.002, ES = 0.35) and RSAmean (p = 0.0002, ES = 0.36) in the uRT. In the sRT, however, no significant pre-post performance changes were observed in RSAbest and RSAmean. In conclusion, 10 weeks of an in-season resistance training on unstable conditions in addition to regular soccer training was effective in improving repeated-sprint ability performance in youth male elite soccer players including maximal linear sprinting and the ability to perform repeated sprint.

Relationship between vertical jumping ability and endurance capacity with internal training loads in professional volleyball players during preseason.

BACKGROUND: This study aimed to quantify internal training load and changes in vertical jumping ability and endurance capacity of professional volleyball players during the preseason, and to explore relationships between players' physical qualities at the beginning of the preseason with internal training load accumulated during the first two weeks of training. METHODS: Sixteen male professional volleyball players from a team participating in the Brazilian National Super League took part in the study. Before and after a 10-week preseason, their vertical jumping ability and endurance capacity were assessed by squat jump, countermovement jump without and with arm swing, and YoYo endurance test, level 1. The internal training load was quantified by the session rating of perceived exertion method. Results were analyzed using analysis of variance, magnitude-based inference and Pearson's correlation. RESULTS: The internal training load varied between 1388±111 arbitrary units (a.u.) and 3852±149 a.u., and performance in all the tests was positively changed (small to moderate effect sizes) at end of preseason training. Significant (P<0.05) very large and large correlations were observed between squat jump (r=-0.81) and YoYo endurance test (r=-0.64) performances and internal training load accumulated during the first two training weeks, respectively. CONCLUSIONS: The internal training load and training strategies undertaken by the investigated team were effective to improve players' vertical jumping ability and endurance capacity. Coaches need to improve these physical qualities of volleyball players in order to improve their tolerance to training.