Sub-maximal heart rate is associated with changes in high-intensity intermittent running ability in professional rugby league players

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.

Use of Inter-Effort Recovery Hypoxia as a New Approach to Improve Anaerobic Capacity and Time to Exhaustion

Putti, Germano Marcolino, Gabriel Peinado Costa, Matheus Silva Norberto, Carlos Dellavechia de Carvalho, Rômulo Cássio de Moraes Bertuzzi, and Marcelo Papoti. Use of inter-effort recovery hypoxia as a new approach to improve anaerobic capacity and time to exhaustion. High Alt Med Biol. 25:68-76, 2024. Background: Although adding hypoxia to high-intensity training may offer some benefits, a significant problem of this training model is the diminished quality of the training session when performing efforts in hypoxia. The purpose of this study was to investigate the effects of training and tapering combined with inter-effort recovery hypoxia (IEH) on anaerobic capacity, as estimated by alternative maximum accumulated oxygen deficit (MAODALT) and time to exhaustion (TTE). Methods: Twenty-four amateur runners performed, for 5 weeks, 3 sessions per week of training consisted of ten 1-minute bouts at 120% (weeks 1-3) and 130% (weeks 4 and 5) of maximum velocity (VMAX) obtained in graded exercise test, separated by a 2-minute interval in IEH (IEH, n = 11, FIO2 = 0.136) or normoxia (NOR, n = 13, fraction of inspired oxygen = 0.209). Before training, after training, and after 1 week of tapering, a graded exercise test and a maximal effort to exhaustion at 120% of VMAX were performed to determine TTE and MAODALT. The results were analyzed using generalized linear mixed models, and a clinical analysis was also realized by the smallest worthwhile change. Results: MAODALT increased only in IEH after training (0.8 ± 0.5 eq.lO2) and tapering (0.8 ± 0.5 eq.lO2), with time x group interaction. TTE increased for the pooled groups after taper (23 ± 11 seconds) and only for IEH alone (29 ± 16 seconds). Clinical analysis revealed a small size increase for NOR and a moderate size increase for IEH. Conclusions: Although the effects should be investigated in other populations, it can be concluded that IEH is a promising model for improving anaerobic performance and capacity. World Health Organization Universal Trial Number: U1111-1295-9954. University's ethics committee registration number: CAAE: 32220020.0.0000.5659.

The discriminative, criterion, and longitudinal validity of small-sided games to assess physical fitness in female basketball players

The validity of small-sided games (SSG) for assessing physical fitness was evaluated in 21 female basketball players from senior (n = 8), under-18 years (n = 6), and under-16 years (n = 7) age categories. Players underwent fitness testing (countermovement jump [CMJ], agility T-test, repeated-sprint ability (RSA) test, and Yo-Yo Intermittent Recovery Test [YYIRT1]) and 3vs3-SSG before and after a 6-week preseason. Player demands were monitored during SSG using local positioning system and heart rate technology. Regarding discriminative validity, senior players produced better CMJ, agility T-test, and YYIRT1 performance (p  < 0.05, effect size [ES] = 1.72-2.25), and more distance and PlayerLoad (p  < 0.05, ES = 1.53-2.47) during SSG than under-18 players following the preseason. For criterion validity, total distance and distance completing high-intensity decelerations during SSG were significantly (p  < 0.05) correlated with CMJ (r = 0.44-0.66), YYIRT1 (r = 0.43-0.63), agility T-test (total distance only, r=-0.51), and RSA test performance (r=-0.49 to -0.52) among all players combined following the preseason. Regarding longitudinal validity, significantly better agility T-test and YYIRT1 performance (p ≤ 0.001, ES = 0.88-0.93) alongside lower heart rate during SSG (p = 0.001, ES = 0.88) were evident for all players combined following the preseason. These results partially support the validity of 3vs3-SSG to assess physical fitness in female basketball players.

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 .

Minimally Invasive Ways to Monitor Changes in Cardiocirculatory Fitness in Running-based Sports: A Systematic Review

This systematic review provides a synthesis of research investigating submaximal protocols to monitor changes in cardiocirculatory fitness in running-based sports. Following PRISMA guidelines, 2,452 records were identified and 14 studies, representing 515 athletes, satisfied the eligibility criteria. While most studies found large associations between changes in heart rate at standardized, submaximal running speeds and changes in aerobic fitness (r=0.51-0.88), three studies failed to establish a relationship (r=0.19-0.35). The intensity of the submaximal protocols seems to be relevant, with changes in running speeds at 90% of maximal heart rate showing larger relationships with changes in aerobic fitness (r=0.52-0.79) compared to 70% of maximal heart rate (r=0.24-0.52). Conversely, changes in post-exercise heart rate variability were very largely associated with changes in aerobic fitness when the testing protocols were less intense (70% of maximal heart rate) (r=0.76-0.88), but not when the test required participants to achieve 90% of their maximal heart rate (r=-0.02-0.06). Studies on post-exercise heart rate recovery revealed inconclusive results (r=-0.01- -0.55), while rate of heart rate increase may be a promising athlete monitoring metric (r=0.08- -0.84) but requires further research. In summary, when executed, analyzed, and interpreted appropriately, submaximal protocols can provide valuable information regarding changes in athlete cardiocirculatory fitness.

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.

Submaximal Fitness Tests in Team Sports: A Theoretical Framework for Evaluating Physiological State

Team-sports staff often administer non-exhaustive exercise assessments with a view to evaluating physiological state, to inform decision making on athlete management (e.g., future training or recovery). Submaximal fitness tests have become prominent in team-sports settings for observing responses to a standardized physical stimulus, likely because of their time-efficient nature, relative ease of administration, and physiological rationale. It is evident, however, that many variations of submaximal fitness test characteristics, response measures, and monitoring purposes exist. The aim of this scoping review is to provide a theoretical framework of submaximal fitness tests and a detailed summary of their use as proxy indicators of training effects in team sports. Using a review of the literature stemming from a systematic search strategy, we identified five distinct submaximal fitness test protocols characterized in their combinations of exercise regimen (continuous or intermittent) and the progression of exercise intensity (fixed, incremental, or variable). Heart rate-derived indices were the most studied outcome measures in submaximal fitness tests and included exercise (exercise heart rate) and recovery (heart rate recovery and vagal-related heart rate variability) responses. Despite the disparity between studies, these measures appear more relevant to detect positive chronic endurance-oriented training effects, whereas their role in detecting negative transient effects associated with variations in autonomic nervous system function is not yet clear. Subjective outcome measures such as ratings of perceived exertion were less common in team sports, but their potential utility when collected alongside objective measures (e.g., exercise heart rate) has been advocated. Mechanical outcome measures either included global positioning system-derived locomotor outputs such as distance covered, primarily during standardized training drills (e.g., small-sided games) to monitor exercise performance, or responses derived from inertial measurement units to make inferences about lower limb neuromuscular function. Whilst there is an emerging interest regarding the utility of these mechanical measures, their measurement properties and underpinning mechanisms are yet to be fully established. Here, we provide a deeper synthesis of the available literature, culminating with evidence-based practical recommendations and directions for future research.

Relationships Among PlayerLoad, High-Intensity Intermittent Running Ability, and Injury Risk in Professional Rugby League Players

PURPOSE

To examine relationships among physical performance, workload, and injury risk in professional rugby league players.

METHODS

Maximal-effort (n = 112) and submaximal (n = 1084) running performances of 45 players were recorded from 1 club over 2 consecutive seasons. Poorer and better submaximal running performance was determined by higher and lower exercise heart rates, respectively. Exponentially weighted moving averages and daily rolling averages were used to assess microtechnology-derived acute and chronic field-based workloads. The associations among within-individual submaximal running performance, workload, and noncontact lower-limb injury were then investigated.

RESULTS

The injury risk associated with poorer submaximal performance was "likely" greater than stable (relative risk = 1.8; 90% confidence interval, 0.9-3.7) and better submaximal performance (relative risk = 2.0; 90% confidence interval, 0.9-4.4). Compared with greater submaximal performance, poorer performance was associated with lower chronic workloads (effect size [d] = 0.82 [0.13], large) and higher acute:chronic workload ratios (d = 0.49 [0.14], small). Chronic workload demonstrated a "nearly perfect" positive relationship with maximal-effort running performance (exponentially weighted moving average, R2 = .91 [.15]; rolling average, R2 = .91 [.14]). At acute:chronic workload ratios >1.9, no differences in injury risk were found between rolling average and exponentially weighted moving average methods (relative risk = 1.1; 90% confidence interval, 0.3-3.8; unclear).

CONCLUSIONS

Reductions in submaximal running performance are related with low chronic workloads, high acute:chronic workload ratios, and increased injury risk. These findings demonstrate that a submaximal running assessment can be used to provide information on physical performance and injury risk in professional rugby league players.