The reliability, validity and sensitivity of an individualised sub-maximal fitness test in elite rugby league athletes.

We aimed to examine the reliability, validity and sensitivity of an individualised sub-maximal fitness test (SMFTIFT60). Nineteen elite rugby league players performed a one-week test-retest of SMFTIFT60. Typical Errors and ICCs were: small (<3.5%) and extremely high (>0.90) for accelerometer-derived variables; moderate (<2.5% points) and moderate to very high (0.71-0.89) for exercise and recovery heart rate (HRex and HRR, respectively). Convergent validity correlations with the 10-week pre-season change in 30-15 Intermittent Fitness Test performance were large for changes in SMFTIFT60 HRex (r = -0.57) and HRR (0.60), and very large for changes in accelerometer measures (range: -0.71 to -0.79). For sensitivity, within-player dose-response relationships between SMFTIFT60 HRex and prior 3-day training loads were negative and ranged from moderate (session ratings of perceived exertion [sRPE-TL], r = -0.34), to large (high-speed running distance, -0.51; acceleration load, -0.73) and very large (heart rate Training Impulse [TRIMP], -0.83). All other relationships were unclear or trivial to small. Physiological and accelerometer-derived measures from the SMFTIFT60 are reliable and valid for the assessment of fitness in rugby league players. Only HRex appears sensitive to acute changes in training load. The SMFTIFT60 could be a useful monitoring tool in team sports.

Comparison of player-dependent and independent high-speed running thresholds to model injury risk in football.

High-speed running (HSR) loads have been linked with non-contact injury risks in team-sports. This study investigated whether player-specific speed zones, reflecting individual fitness characteristics, impact the associations between non-contact injury and acute and chronic HSR loads. Semi-professional soccer players from two clubs (n = 47) were tracked over two seasons using 10 Hz GPS (5552 observations). HSR distances were calculated arbitrarily (≥5.5 m·s-1), and in an individualised fashion based on the final speed of the 30-15 intermittent fitness test. Cumulative running loads were represented by exponentially weighted moving averages with 7-(acute) and 28-day (chronic) decay parameters. Physiotherapists collected non-contact, lower-limb, time-loss injury data (n = 101). Injury models using session type (training vs matches), coach, as well as arbitrary or individualised running loads were constructed via mixed-effect logistic regression. Session type had the largest effect on injury (training vs match OR = 0.28; 95%CI:0.17-0.44). Variations in individualised or arbitrary acute and chronic HSR loads within the mid-range of the observed data had negligible effects on predicted injury risk. However, the uncertainty of estimated effects at extreme values of acute and chronic HSR loads prevented any conclusive findings. Therefore, the efficacy of using customised speed thresholds in quantifying load for injury risk mitigation purposes remains unclear.

Determination of locomotor qualities in elite Australian Football: A pragmatic approach.

The study examined the utility of surrogate measures of athletic performance to determine locomotor qualities (maximal aerobic velocity and peak velocity) in elite Australian Football (AF). 29 professional AF players undertook aerobic fitness (3km time-trial [TT] and 30-15 Intermittent Fitness Test [30-15 IFT]) and peak velocity (PV; 50 m maximal sprints using 10Hz GPS) assessments in pre-season. Characteristics of TT performance (mean velocity, 500m and 1km splits) were compared with a surrogate for maximal aerobic velocity (MAV; 80% of 30-15 IFT final velocity). PVs derived from sprint tests were compared to those attained in AF matches (10 Hz GPS). Higher Pearson correlations were observed between MAV versus the fastest 500m (r = 0.74) and 1km (r = 0.75) of the 3km TT, but they were not superior to mean velocity (r = 0.72; p ≥ 0.30) which also demonstrated the lowest bias (p ≤ 0.01) and equivalent typical errors (0.16-0.17 m.s-1). Peak velocity was higher across match observations (0.28, CI: ± 0.17 m.s -1, p = 0.017) versus sprint tests. There was no impact of playing position on the determination of locomotor qualities using surrogate measures of locomotor qualities. Locomotor qualities can be determined practically using 10Hz GPS devices during 3km time-trials and competitive matches (assuming appropriate signal quality), without additional fitness assessments.

Rescheduling Part 2 of the 11+ reduces injury burden and increases compliance in semi-professional football.

Although the 11+ program has been shown to reduce injuries in sub-elite football, program compliance is typically poor, suggesting that strategies to optimize delivery are necessary. This study investigated the effect of rescheduling Part 2 of the three-part 11+ program on program effectiveness. Twenty-five semi-professional football clubs were randomly allocated to either a Standard-11+ (n = 398 players) or P2post group (n = 408 players). Both groups performed the 11+ program at least twice a week throughout the 2017 football season. The Standard-11+ group performed the entire 11+ program before training activities commenced, whereas the P2post group performed Parts 1 and 3 of the 11+ program before and Part 2 after training. Injuries, exposure, and individual player 11+ dose were monitored throughout the season. No significant between group difference in injury incidence rate (P2pos t vs Standard-11+ = 11.8 vs 12.3 injuries/1000 h) was observed. Severe time loss injuries > 28 days (33 vs 58 injuries; P < .002) and total days lost to injury (4303 vs 5815 days; P < .001) were lower in the P2post group. A higher 11+ program dose was observed in the P2post (29.1 doses; 95% CI 27.9-30.1) versus Standard-11+ group (18.9 doses; 95% CI 17.6-20.2; P < .001). In semi-professional football, rescheduling Part 2 of the 11+ program to the end of training maintained the effectiveness of the original 11+ program to reduce injury incidence. Importantly, rescheduling Part 2 improved player compliance and reduced the number of severe injuries and total injury burden, thereby enhancing effectiveness of the 11+ program.

Individualisation of speed thresholds does not enhance the dose-response determination in football training.

This study examined the utility of a range of approaches used to develop player-dependent speed zones in time-motion analysis (TMA), in determining the dose-response (internal load) of daily football training. Daily external (10 Hz GPS) and internal load (heart rate metrics, ratings of perceived exertion [RPE], wellness ratings) measures were tracked for 22 International women's football players during a 21-day training camp. High-speed (HSR) and very high speed running (VHSR) were determined according to arbitrary speed thresholds, as well as using a range of different individualization approaches that included the velocities corresponding to the heart rate deflection point, maximal aerobic speed, YYIR1 performance, and maximal sprint speed (MSS). Within-player correlations between the TMA approaches versus internal load measures quantified the dose-response to training. Correlations between HSR and VHSR vs. RPE were large (r = 0.53-0.67), with the exception of VHSR for the MSS technique (moderate; r = 0.44). HSR was very-largely associated with heart rate indices (r = 0.72-0.78), again with the exception of MSS (large; r = 0.60-0.67). Using a range of different fitness characteristics to individualise speed thresholds did not enhance the dose-response determination to daily fluctuations in external load, and was worsened with MSS per se.

Measuring Vertical Stiffness in Sport With Accelerometers: Exercise Caution!

Eggers, TM, Massard, TI, Clothier, PJ, and Lovell, R. Measuring vertical stiffness in sport with accelerometers: Exercise caution! J Strength Cond Res 32(7): 1919-1922, 2018-This study aimed to determine the measurement accuracy of triaxial accelerometers, to determine vertical stiffness (Kvert) during overground running, and to examine the influence of device location. Seventeen healthy adults wore 2 triaxial accelerometers (positioned between scapulae and at lumbar spine) during a 2-minute continuous 20-m shuttle run (12 km·h), which was repeated 7 days later. Accelerometer-derived Kvert data were compared with that calculated from corresponding force-plate ground contacts (criterion measure). Moderate correlations (r = 0.65-0.66) between the accelerometer and criterion measure were identified, irrespective of unit location. However, accelerometer-determined Kvert had questionable reliability in both positions (intraclass correlation coefficient = 0.70-0.71). These results suggest caution be taken when using accelerometer-derived Kvert during overground running.

Relative Age, Maturation and Physical Biases on Position Allocation in Elite-Youth Soccer.

This study assessed the contribution of relative age, anthropometry, maturation, and physical fitness characteristics on soccer playing position (goalkeeper [GK], central-defender [CD], lateral-defender [LD], central-midfield [CM], lateral-midfielder [LM], and forward [FWD]) for 465 elite-youth players (U13-U18's). U13-14 CD were relatively older than LD and CM (likely small effects). CD and GK were generally taller and heavier (likely small to very-likely moderate effects) than other players at each developmental stage and were advanced maturers at U13-14 (very-likely small to likely moderate effects). GK had inferior agility (very-likely small to likely moderate effects), endurance (very-likely small to likely moderate effects), and sprint capacities (likely small-moderate effects) vs. outfield positions at U13-14, but deficits in anaerobic phenotypes were diminished in U15-16 and U17-18. Position specific fitness characteristics were distinguished at U15-16 (likely small) and U17-18 (likely moderate), where LM were faster than their central counterparts. In summary, relative age, maturation and anthropometric characteristics appear to bias the allocation of players into key defensive roles from an early development stage, whereas position-specific physical attributes do not become apparent until the latter stages of talent development in outfield players. Given the inter-individual trajectories of physical development according to biological maturation, playing position allocation might be considered 'plastic' by selectors, until complete-maturity is achieved.

Acute neuromuscular and performance responses to Nordic hamstring exercises completed before or after football training.

The optimal scheduling of Nordic Hamstring exercises (NHEs) relative to football training sessions is unknown. We examined the acute neuromuscular and performance responses to NHE undertaken either before (BT) or after (AT) simulated football training. Twelve amateur players performed six sets of five repetitions of the NHE either before or after 60 min of standardised football-specific exercise (SAFT60). Surface electromyography signals (EMG) of the hamstring muscles were recorded during both the NHE, and maximum eccentric actions of the knee flexors (0.52 rad · s-1) performed before and after the NHE programme, and at 15 min intervals during SAFT60. Ten-metre sprint times were recorded on three occasions during each 15 min SAFT60 segment. Greater eccentric hamstring fatigue following the NHE programme was observed in BT versus AT (19.8 %; very likely small effect), which was particularly apparent in the latter range of knee flexion (0-15°; 39.6%; likely moderate effect), and synonymous with hamstring EMG declines (likely small-likely moderate effects). Performing NHE BT attenuated sprint performance declines (2.0-3.2%; likely small effects), but decreased eccentric hamstring peak torque (-14.1 to -18.9%; likely small effects) during football-specific exercise. Performing NHE prior to football training reduces eccentric hamstring strength and may exacerbate hamstring injury risk.

Hamstring Fatigue and Muscle Activation Changes During Six Sets of Nordic Hamstring Exercise in Amateur Soccer Players.

The Nordic hamstring exercise (NHE) is a bodyweight movement commonly prescribed to increase eccentric hamstring strength and reduce the incidence of strain injury in sport. This study examined hamstring fatigue and muscle activation responses throughout 6 sets of 5 repetitions of the NHE. Ten amateur-level soccer players performed a single session of 6 sets of 5 repetitions of NHE. Maximal eccentric and concentric torque output (in newton meters) was measured after every set. Hamstrings electromyograms (EMG) were measured during all maximal contractions and exercise repetitions. Hamstring maximal eccentric torque was reduced throughout the range of motion after only a single set of NHE between 7.9 and 17.1% (p ≤ 0.05), with further reductions in subsequent sets. Similarly, maximal concentric torque reductions between 7.8 and 17.2% were observed throughout the range of motion after 1 set of NHE (p ≤ 0.05). During the descent phase of the NHE repetitions, hamstring muscle activity progressively increased as the number of sets performed increased. These increases were observed in the first half of the range of motion. During the ascent phase, biceps femoris muscle activity but not medial hamstrings was reduced from the start of exercise during latter sets of repetitions. These data provide unique insight into the extent of fatigue induced from a bodyweight only exercise after a single set of 5 repetitions. Strength and conditioning coaches need to be aware of the speed and extent of fatigue induced from NHE, particularly in practical settings in which this exercise is now prescribed before sport-specific training sessions (i.e., the FIFA-11 before soccer training).

The Dose-Response in Elite Soccer: Preliminary Insights From Menstrual-Cycle Tracking During the FIFA Women's World Cup 2019.

PURPOSE: This preliminary study examined the influence of estimated menstrual-cycle (MC) phase on responses to soccer matches and training sessions in preparation for and during the FIFA (Fédération internationale de football association) Women's World Cup 2019. METHODS: Twenty outfield players representing a national team were tracked over a 45-day period. External (10-Hz global positioning system; total and distance covered at high-metabolic power [≥20 W·kg-1]) and internal load measures (minutes ≥80% heart-rate maximum, sessional ratings of perceived exertion) were collected during all training and matches, with single-item wellness measures (fatigue, soreness, sleep quality, and sleep duration) collected each morning prior to activity. MC phase was estimated individually via an algorithm, informed from pretournament survey responses and ongoing symptom reporting (FitrWoman). Model comparison statistics were used to determine the impact of estimated MC phase in nonhormonal contraceptive users (n = 16). RESULTS: Sessional rating of perceived exertion responses to total distances ≥5 km were higher during the luteal phase (+0.6-1.0 au; P ≤ .0178) versus menstruation (phase 1), but no other observable dose-response trends were observed. Sleep, fatigue, and soreness ratings were not typically associated with MC phase, with the exception of exacerbated fatigue ratings in luteal versus follicular phase 48 hours postmatch (-0.73 au, P = .0275). CONCLUSIONS: Preliminary findings suggest that estimated MC phase may contribute to the understanding of the dose-response to soccer training and matches.

Inconsistencies in the perceived impact of the menstrual cycle on sport performance and in the prevalence of menstrual cycle symptoms: A scoping review of the literature.

OBJECTIVES: This scoping review aimed to summarize the findings of studies regarding the perceived impact of the menstrual cycle on athletic performance, as well as the prevalence of negative menstrual cycle symptoms. DESIGN: Scoping review. METHODS: Three databases were searched and the Preferred Reporting Items for Systematic reviews and Meta Analyses extension for Scoping Reviews (PRISMA-ScR) was used as guidance. RESULTS: A total of 39 studies were included in the final analysis. Between 2.8 and 100 % of athletes reported their performance being negatively impacted by their menstrual cycle, and the main reason was the occurrence of menstrual cycle symptoms. Additionally, a large variability in the prevalence of menstrual cycle symptoms was reported in the different studies mainly due to methodological differences and recall biases. CONCLUSIONS: Similarly, as to what has been reported in reviews summarizing performance outcomes during different menstrual cycle phases, this review highlights the high degree of variability between how athletes perceive to be impacted by their menstrual/hormonal contraceptive cycle. REGISTRATION: The protocol of this scoping review was registered at the Open Science Framework on 14 September 2023 (osf.io/efu9x).

A Methodological Comparison of Protocols and Analytical Techniques to Assess the Outcome Measures of Submaximal Fitness Tests.

BACKGROUND: Submaximal fitness test (SMFT) outcome measures are frequently collected with a wide array of technologies and methodological approaches. PURPOSE: To examine the test-retest reliability of various SMFT outcome measures derived from different protocols and analytical techniques. METHODS: Twenty-six semiprofessional adult soccer players performed 3 SMFT protocols, including 2 continuous (3 min, 11 and 12.8 km·h-1) and 1 intermittent (4 × 50 m, 18 km·h-1) twice, each separated by 7 days. Heart-rate (HR) indices (exercise HR, HR recovery) and scapula-mounted (PlayerLoad vector magnitude) and foot-mounted (flight time and contact time, stride length) microelectrical mechanical system-derived variables were collected using different time frames and analytical approaches adopted in the literature and practice. Absolute reliability was quantified as the group mean difference, typical error of measurement, also expressed as the coefficient of variation (where appropriate) and standardized units (ie, d). Intraclass correlation coefficient was used to quantify relative reliability. RESULTS: The highest degrees of reliability were evident for exercise HR (typical error: 1.0%-1.6% points), the vertical component of PlayerLoad (expressed in arbitrary units; coefficient of variation: 5.5%-7.0%), and contact time (coefficient of variation: 1.5%-3.0%). These estimates were not influenced by SMFT protocol or analytical approach. All other measures displayed poorer reliability and/or were different between protocols and analytical methods. CONCLUSIONS: SMFT protocols impact the test-retest reliability of various outcome measures; however, exercise HR, vertical PlayerLoad, and contact time (derived from foot-mounted micro-electrical mechanical systems) appear to have stable measurement properties to assist the assessment of aerobic capacity and lower-limb neuromuscular status, respectively.

Assessing criterion and longitudinal validity of submaximal heart rate indices as measures of cardiorespiratory fitness: A preliminary study in football.

OBJECTIVES: To evaluate the criterion and longitudinal validity of field- and laboratory-derived heart rate (HR) indices of resting and submaximal fitness tests (SMFTs) as measures of cardiorespiratory fitness. DESIGN: Observational, repeated measures. METHODS: Twenty-nine semi-professional footballers participated. Laboratory assessments took place at the start and end of a preseason training period, whereby resting, SMFT HR-derived indices, and criterion measures of cardiorespiratory fitness (running economy [RE], maximal oxygen uptake [V̇O2 max] and aerobic speed [MAS]) were collected. Throughout this training period, two field-based SMFT protocols, prescribed at different intensities, were administered weekly. Individual slopes were calculated from the analysis of within-athlete change scores. Associations between laboratory and field measures were assessed via Pearson's correlation coefficient (r) and linear regression models. RESULTS: Relationships between SMFT HR-derived indices from laboratory and field were very-large for exercise HR (r = 0.74 to 0.87) and moderate to very-large for HR recovery (0.43 to 0.76). Moderate to very-large inverse relationships were observed between exercise HR and HR recovery with V̇O2 max and MAS (-0.41 to -0.78), whereas resting HR showed no substantial relationships. Changes in exercise HR showed large and very-large inverse correlations with preseason changes in V̇O2 max (-0.54 to -0.60) and MAS (-0.64 to -0.83). Relationships between changes in HR recovery and maximal cardiorespiratory criterion measures were moderate to large (-0.32 to -0.63). CONCLUSION: SMFT exercise HR is a valid proxy measure of cardiorespiratory fitness irrespective of test setting, whereas the validity of HRR remains elusive and appears to vary between exercise intensities.

Warm-up strategies of professional soccer players: practitioners' perspectives.

Recent research has challenged the typical pre-match and half-time (HT) interval warm-up (WU) routines currently used by professional soccer players. This study surveyed 2010/11 season WU strategies and their underpinning scientific reasoning and situational factors via an internet-based questionnaire, which was distributed to English Premier League and Championship practitioners, of which 43% responded. The pre-match WU duration was 30.8 (8.2) min, ranging between 15-45 min, and 89% of practitioners administered a WU of ≥ 25 min. Respondents also reported a 12.4 (3.8) min period between the end of the WU and match kick-off. Eighty-nine per cent recognised the physiological benefits of re-WUs during this "down-time" period, with 63% instructing players to engage in such activity. During HT, 58% instructed players to re-WU either on the pitch or within stadia facilities, but "unwillingness of the coach/manager" (42%) and a "lack of time" (63%) were major constraints. Practitioners reported that 2.6 (1.6) min might be available for HT re-WUs. Factors such as match regulations, league policy, and stadia facilities were not generally considered as major barriers to the delivery of WUand re-WU strategies. We suggest that researchers consider the time-demands and barriers faced by practitioners whendeveloping experimental designs to examine WU regimens.

Maximum speed exposures in Australian rules football: do methods matter?

This study compared weekly near-to-maximum speed exposure data when determined via different methods and criteria. Forty-seven professional Australian rules football (AF) players undertook pre-season sprint assessments (PSSA) via 3 × 50 m maximal efforts using 10 Hz GPS over two consecutive seasons. The same technology was used continually during the in-season to identify maximum speeds attained in training and matches. Weekly near-to-maximal speed (MS) exposure counts were aggregated for speeds ≥80%, ≥85%, ≥90% and ≥95% of their individual maximum for both determination approaches. Weekly near-to-MS exposures was lower (p < 0.0001) when determined from in-season monitoring for ≥80% (-1.26; CI: -1.58 to -0.93), ≥85% (-0.78; CI: -0.97 to -0.59), ≥90% (-0.42; CI: -0.53 to -0.32), and ≥95% (-0.09; CI: -0.12 to -0.06) versus PSSA, with no effect of playing position (P ≥ 0.161). Although ≥80% and ≥85% near-to-maximum speed exposure data was meaningfully influenced by the determination method, the effect was somewhat trivial at higher speed criteria (≥90% and ≥95%) often considered important for performance gains and injury risk reduction purposes. Maximum speed determination methods therefore may be used interchangeably, and discrete sprint assessments may not be necessary for this purpose.

Scheduling Concurrent Training 48 versus 72 h after Simulated Match Play: Effects on Neuromuscular Function and Fatigue.

INTRODUCTION: Scheduling concurrent training (CT) during the in-season microcycle in field-based team sport is driven by prematch and postmatch recovery. This study examined the neuromuscular function, fatigue, and soreness responses to CT administered 48 h (match day (MD) + 2) versus 72 h (MD + 3) after match. METHODS: Ten male recreational-level team sport athletes were monitored daily during two 5-d microcycles, which began with a simulated match (Soccer-specific Aerobic Field Test (SAFT90)) and CT performed either 48 or 72 h after match. Maximal voluntary force, quadriceps maximum EMG, voluntary activation, muscle contractile function (evoked twitch responses), muscle soreness, and fatigue were assessed immediately before and after the SAFT90, and every 24 up to 96 h after match. Outcome measures were also assessed immediately after CT. The CT consisted of an intermittent sprint protocol and a lower limb resistance training session separated by 1 h. RESULTS: Immediately after the SAFT90 in both conditions, maximal voluntary force was below baseline (mean change (Δ), -14.6% ± 10.0%; P = 0.03), recovering 48 h post. Quadriceps contractile function (Δ, -31.5% ± 11.4%; P = 0.003) and voluntary activation (Δ, -8.9 ± 6.2%; P = 0.003) were also hampered after the SAFT90, recovering 24 h post in both conditions. In addition, the SAFT90 elicited elevated levels of fatigue and muscle soreness that recovered 24 h after the SAFT90 before increasing at 72 and 96 h post in the MD + 2 and MD + 3 conditions, respectively. CONCLUSIONS: Recovery of fatigue was only observed at the end of the microcycle when CT was prescribed on MD + 2. Therefore, CT scheduled early (MD + 2) in the microcycle might avoid compromising forthcoming match preparation.

Submaximal Fitness Test in Team Sports: A Systematic Review and Meta-Analysis of Exercise Heart Rate Measurement Properties.

BACKGROUND: Submaximal fitness tests (SMFT) are a pragmatic approach for evaluating athlete's physiological state, due to their time-efficient nature, low physiological burden and relative ease of administration in team sports settings. While a variety of outcome measures can be collected during SMFT, exercise heart rate (HRex) is the most popular. Understanding the measurement properties of HRex can support the interpretation of data and assist in decision making regarding athlete's current physiological state and training effects. OBJECTIVES: The aims of our systematic review and meta-analysis were to: (1) establish meta-analytic estimates of SMFT HRex reliability and convergent validity and (2) examine the moderating influence of athlete and protocol characteristics on the magnitude of these measurement properties. METHODS: We conducted a systematic literature search with MEDLINE, Scopus and Web of Science databases for studies published up until January 2022 since records began. Studies were considered for inclusion when they  included team sports athletes and the reliability and/or convergent validity of SMFT HRex was investigated. Reliability statistics included the group mean difference (MD), typical error of measurement (TE) and intraclass correlation coefficient (ICC) derived from test-retest(s) designs. Pearson's correlation coefficient (r) describing the relationship between SMFT HRex and a criterion measure of endurance performance was used as the statistic for convergent validity. Qualitative assessment was conducted using risk of bias assessment tool for non-randomised studies. Mixed-effects, multilevel hierarchical models combined with robust variance estimate tests were performed to obtain pooled measurement property estimates, effect heterogeneity, and meta-regression of modifying effects. RESULTS: The electronic search yielded 21 reliability (29 samples) and 20 convergent validity (29 samples) studies that met the inclusion criteria. Reliability meta-analysis indicated good absolute (MD = 0.5 [95% CI 0.1 to 0.9] and TE = 1.6 [95% CI 1.4 to 1.9] % points), and high relative (ICC = 0.88 [95% CI 0.84 to 0.91]) reliability. Convergent validity meta-analysis indicated an inverse, large relationship (r = - 0.58 [95% CI - 0.62 to - 0.54]) between SMFT HRex and endurance tests performance. Meta-regression analyses suggested no meaningful influence of SMFT protocol or athlete characteristics on reliability or convergent validity estimates. CONCLUSIONS: Submaximal fitness test HRex is a reliable and valid proxy indicator of endurance performance in team sport athletes. Athlete and SMFT protocol characteristics do not appear to have a meaningful effect on these measurement properties. Practitioners may implement SMFT HRex for monitoring athlete's physiological state by using our applied implications to guide the interpretation of data in practice. Future research should examine the utility of SMFT HRex to track within-athlete changes in aerobic capacity, as well as any further possible effects of SMFT protocols design elements or HRex analytical methods on measurement properties. Registration Protocol registration can be found in Open Science Framework and available through https://doi.org/10.17605/OSF.IO/9C2JV .

A Worldwide Survey on the Practices and Perceptions of Submaximal Fitness Tests in Team Sports.

PURPOSE: To survey team-sport practitioners on current practices and perceptions of submaximal fitness tests (SMFTs). METHODS: A convenience sample of team-sport practitioners completed an online survey (September to November 2021). Descriptive statistics were used to obtain information of frequencies. A mixed-model quantile (median) regression was employed to assess the differences between the perceived influence of extraneous factors. RESULTS: A total of 66 practitioners (74 discrete protocols) from 24 countries completed the survey. Time-efficient and nonexhaustive nature were considered the most important features of implementation. Practitioners prescribed a range of SMFTs, administered mostly on a monthly or weekly basis, but scheduling strategies appeared to differ across SMFT categories. Cardiorespiratory/metabolic outcome measures were collected in most protocols (n = 61; 82%), with the majority monitoring heart-rate-derived indices. Subjective outcome measures (n = 33; 45%) were monitored exclusively using ratings of perceived exertion. Mechanical outcome measures (n = 19; 26%) included either a combination of locomotor outputs (eg, distance covered) or variables derived from microelectrical mechanical systems. The perceived influence of extraneous factors on measurement accuracy varied according to outcome measure, and there was a lack of consensus among practitioners. CONCLUSIONS: Our survey showcases the methodological frameworks, practices, and challenges of SMFTs in team sports. The most important features for implementation perhaps support the use of SMFTs as a feasible and sustainable tool for monitoring in team sports. The wide variety of protocols, scheduling strategies, and outcome measures, along with their associated collection and analytical techniques, may reflect the absence of robust evidence regarding the application of SMFTs in team sports.

Acute Neuromuscular Response to Team Sports-Specific Running, Resistance, and Concurrent Training: A Crossover Study.

PURPOSE: This study aimed to examine the changes in muscle contractile function, voluntary activation, and muscle damage after lower limb resistance training (RT), intermittent sprint exercise, and concurrent training (CT). METHODS: Ten male, recreational team sport athletes with a history of RT participated in a randomized crossover study involving an intermittent sprint protocol (ISP), lower limb RT, and CT (ISP and RT separated by 1 h). Before (PRE), immediately after (POST), 24 h and 48 h after each exercise condition, quadriceps muscle activation, voluntary activation, muscle contractile function (evoked twitch responses), creatine kinase, muscle soreness, and Profile of Mood States (POMS)-fatigue were recorded. RESULTS: Quadriceps contractile function was hampered in all conditions, with a significantly greater decline observed POST RT (58.4% ± 18.0%) and CT (54.8% ± 8.6%) compared with ISP (35.9% ± 10.7%, P < 0.05), recovering at 48 h after all exercise conditions. POMS-fatigue ratings increased at POST in all conditions with CT and ISP eliciting the greatest increase, returning to baseline 48 h after all exercise conditions. Quadriceps muscle soreness remained elevated from PRE at 48 h after all exercise conditions. No changes across time were observed for voluntary activation and quadriceps surface EMG amplitude after any exercise condition. The volume and load lifted in the RT session was unaffected by previous intermittent exercise (ISP) in CT. CONCLUSIONS: RT impairs contractile function, which is not exacerbated when performed 1 h after the ISP. Contractile function after all exercise conditions displayed the same recovery profile (48 h) despite the postexercise decrement being smaller after the ISP compared with RT and CT. Previous intermittent sprint exercise does not negatively affect the volume of exercise performed in a lower limb RT session.