The yo-yo test: reliability and association with a 20-m shuttle run and VO(2max)

Assessment of Maximum Oxygen Uptake in Elite Youth Soccer Players: A Comparative Analysis of Smartwatch Technology, Yoyo Intermittent Recovery Test 2, and Respiratory Gas Analysis

The maximum oxygen uptake (VO2max) is a critical factor for endurance performance in soccer. Novel wearable technology may allow frequent assessment of V̇O2max during non-fatiguing warm-up runs of soccer players with minimal interference to soccer practice. The aim of this study was to assess the validity of VO2max provided by a consumer grade smartwatch (Garmin Forerunner 245, Garmin, Olathe, USA, Software:13.00) and the YoYo Intermittent Recovery Run 2 (YYIR2) by comparing it with respiratory gas analysis. 24 trained male youth soccer players performed different tests to assess VO2max: i) a treadmill test employing respiratory gas analysis, ii) YYIR2 and iii) during a non-fatiguing warm-up run of 10 min wearing a smartwatch as recommended by the device-manufacturer on 3 different days within 2 weeks. As the device-manufacturer indicates that validity of smartwatch-derived VO2max may differ with an increase in runs, 16 players performed a second run with the smartwatch to test this claim. The main evidence revealed that the smartwatch showed an ICC of 0.37 [95% CI: -0.25; 0.71] a mean absolute percentage error (MAPE) of 5.58% after one run, as well as an ICC of 0.54 [95% CI: -0.3; 8.4] and a MAPE of 1.06% after the second run with the smartwatch. The YYIR2 showed an ICC of 0.17 [95% CI: -5.7; 0.6]; and MAPE of 4.2%. When using the smartwatch for VO2max assessment in a non-fatiguing run as a warm-up, as suggested by the device manufacturer before soccer practice, the MAPE diminishes after two runs. Therefore, for more accurate VO2max assessment with the smartwatch, we recommend to perform at least two runs to reduce the MAPE and enhance the validity of the findings.

Analysis of Accumulated Workloads and Performance Testing Across a Collegiate Women's Lacrosse Season

ABSTRACT

Fields, JB, Kuhlman, NM, Jagim, AR, Dulak-Sigler, C, and Jones, MT. Analysis of accumulated workloads and performance testing across a collegiate women's lacrosse season. J Strength Cond Res 37(11): 2213-2221, 2023-Monitoring accumulated workloads, acute:chronic workload ratios (ACWR), and training monotony (TM) are practical methods for monitoring athlete physical stress. Performance testing provides useful information about the changing nature of physical abilities. Therefore, the purpose was to examine differences in accumulated workloads based on session type, explore seasonal trends in ACWR and TM, and assess changes in performance assessments in collegiate women's lacrosse athletes. Athletes, who were identified as starters ( n = 12), wore positional monitoring technology during training sessions ( n = 61) and games ( n = 17) and completed preseason and postseason assessments of speed, agility, power (jump tests), strength, aerobic capacity, and body composition. Separate 1-way analyses of variance were used to determine differences in accumulated workloads for session type and differences in performance assessments from preseason to postseason ( p < 0.05). When compared with games, practice sessions elicited greater ( p < 0.001) accumulated total distance, player load, repeated high-intensity efforts, accelerations, change of direction, explosive efforts, high-speed efforts ( p = 0.002), and high-speed distance ( p = 0.002). Throughout the season, ACWR and TM ranged from 0.16 to 1.40 AU and 0.68-1.69 AU, respectively. The 40-yd sprint ( p < 0.001) and pro-agility ( p < 0.001) improved from preseason to postseason, whereas no changes in aerobic capacity, lower-body power, or strength were observed ( p > 0.05). The monitoring of accumulated loads, ACWR and TM, and performance tests revealed novel information about the seasonal demands of collegiate women's lacrosse. Women lacrosse players are able to improve speed and agility throughout the season, while maintaining strength, power, and endurance, with minimal reductions in fat-free mass.

Performance in the Yo-Yo Intermittent Recovery Test May Improve with Repeated Trials: Does Practice Matter?

The Yo-Yo Intermittent Test is frequently used to monitor changes in athletes' performance in response to different interventions. However, the question remains as to whether, and to what extent, retakes of this test would contribute to these changes. This case study sought to determine the magnitude of practice effects, involving test repetition, on performance in the Yo-Yo Intermittent Recovery Test. A recreational soccer player performed four attempts of the Yo-Yo Intermittent Recovery Test-Level 1 (YYIR1) with a week's rest in between. The same participant repeated this test protocol (four attempts of the YYIR1) again after six months. Changes in distance covered, level achieved, maximal oxygen uptake, and heart rate between the first and last attempt were assessed. The smallest worthwhile change (SWC), the coefficient of variation (CV), and the 2CV were calculated to identify a trivial, a possibly meaningful, and a certainly meaningful change in YYIR1 performance. The distance covered in the first set of measurements increased from 1320 m to 1560 m (15.4%), which corresponds to a 4.6% increase in the level achieved (from 16.6 to 17.4). Similarly, the distance covered in the second set of measurements increased from 1280 m to 1560 m (17.9%), which corresponds to a 5.5% increase in the level achieved (from 16.5 to 17.4). The participant's performance changes fell outside of the SWC and the CV, but not the 2CV during both sets of measurements. These improvements in YYIR1 performance may be ascribed to practice with repeated attempts of the test by improving running technique at the turning point and/or by simply increasing the linear speed. This fact should always be kept in mind when interpreting the effects of training. Practitioners should differentiate between practice effects associated with repeated test execution and adaptation induced by conducting sport-specific training.

Effects of self-paced high-intensity interval training and moderate-intensity continuous training on the physical performance and psychophysiological responses in recreationally active young adults

This study aimed to compare the effects of 8-week self-paced high-intensity interval training (HIIT) vs. self-paced moderate-intensity continuous training (MICT) on the physical performance and psychophysiological responses of young adults. Twenty-eight recreationally active young adults (age: 21.1 ± 1.6 years) were randomly assigned to either the self-paced HIIT (n = 14) or the MICT (n = 14) group training protocol. The HIIT consisted of two 12-24 x 30 seconds of high-intensity runs interspersed by 30 seconds of recovery. The MICT completed 24-48 minutes of continuous running. Before and after the 8-week interventions the following tests were completed: maximum oxygen consumption (V̇O_2max) estimated from the Yo-Yo Intermittent Recovery Test level 1 (YYIRTL-1), repeated sprint ability (RSA), 10-30-m sprint test, change of direction test (T-drill), countermovement jump (CMJ) and squat jump (SJ), and triple hop distance test (THD). Training rating of perceived exertion (RPE) and physical activity enjoyment scale (PACES) were assessed during the training programme. The HIIT resulted in greater improvement in YYIRTL-1, V̇O_2max, RSA and T-drill performances compared to the MICT. Furthermore, RPE and PACES values were higher in the HIIT than the MICT. This study suggested that self-paced HIIT may be a more effective training regime to improve aerobic fitness with greater physical enjoyment in recreationally active young adults.

Relationship Between the 20-m Multistage Fitness Test and 2.4-km Run in Law Enforcement Recruits

ABSTRACT

Lockie, RG, Dawes, JJ, Moreno, MR, Cesario, KA, Balfany, K, Stierli, M, Dulla, JM, and Orr, RM. Relationship between the 20-m multistage fitness test and 2.4-km run in law enforcement recruits. J Strength Cond Res 35(10): 2756-2761, 2021-In the United States, the 2.4-km run is arguably the most common law enforcement aerobic assessment. Potential limitations are that recruits use an internal pacing strategy, the test requires fewer direction changes, and less-fit recruits run for longer. The 20-m multistage fitness test (20MSFT) is commonly used internationally to assess aerobic fitness in law enforcement recruits and provides an external pacing strategy. This study documented sex differences between the 2.4-km run and 20MSFT in law enforcement recruits, and between-test relationships. Retrospective analysis on 8 academy classes (463 men and 87 women) from 1 agency was conducted. The 20MSFT was completed before academy and the 2.4-km run in the first week. Between-sex comparisons in the 2.4-km run and 20MSFT were conducted with independent-samples t-tests and effect sizes. Estimated V̇o2max from the tests was compared with paired-samples t-tests. Correlations and linear regression calculated 2.4-km run and 20MSFT relationships. There were significant between-sex differences for the 2.4-km run and 20MSFT (p < 0.01), with moderate (d = 0.9) and small (d = 0.4) effects, respectively. Estimated 2.4-km run V̇o2max was greater than that from the 20MSFT (p < 0.01). The 2.4-km run had significant relationships with the 20MSFT (r = -0.6), although the regression equations were low (r2 = 0.30-0.37). Between-sex differences in the 20MSFT seemed less than for those in the 2.4-km run. Nonetheless, even with significant relationships between the tests, the 20MSFT induces a higher running intensity and direction changes. This may limit transferability with the 2.4-km run in law enforcement recruits.

Applicability of Field Aerobic Fitness Tests in Soccer: Which One to Choose?

A desire to make fitness testing cheaper and easier to conduct in a team-sport setting has led to the development of numerous field aerobic fitness tests. This has contributed to a growing confusion among strength and conditioning coaches about which one to use. The main aim of this narrative review was to examine the reliability, validity, sensitivity and usefulness of the commonly used field aerobic fitness tests and to provide practical guidelines for their use in soccer. The University of Montreal track test (UMTT) and Vam Eval test seem the best options for estimation of maximal oxygen uptake (VO_2max) while the highest signal-to-noise ratio of the 30-15 intermittent fitness test (30-15IFT) suggests its superior sensitivity to track changes in fitness. The UMTT and 30-15IFT are the best solutions for prescription of long and short high-intensity interval training sessions, respectively. All field tests mostly present with marginal usefulness, but the smallest worthwhile change for UMTT or Vam Eval test, Yo-YoIRT2 and 30-15IFT are smaller than their stage increment making the improvement of only one stage in the test performance already worthwhile. Strength and conditioning coaches are advised to choose the test based on their specific purpose of testing.

Intensity-Modified Recreational Volleyball Training Improves Health Markers and Physical Fitness in 25-55-Year-Old Men

The present study is aimed at determining the effects of intensity-modified recreational volleyball training on health markers and physical fitness in healthy middle-aged men. Thirty-four healthy untrained men aged 25–55 years were randomized to either a modified recreational volleyball group (MRV, n = 17) or a recreational volleyball group (RV, n = 17). Both groups performed volleyball training twice a week over 12 weeks, with participants in MRV playing a modified game with higher intensity due to shorter breaks between rallies. The small to moderate improvements of both groups were observed in SBP (MRV g_av = −0.50 [-0.67, -0.33] vs. RV g_av = −0.37 [-0.55, -0.20]) to a similar extent (p = 0.12). However, only the MRV significantly improved (p < 0.001) the mean body weight (g_av = −0.35 [-0.52, -0.18]) and BMI (g_av = −0.39 [-0.56, -0.22]) to a moderate extent and the YYIR1 performance (g_av = 2.45 [2.22, 2.69]) to a large extent. Even though both groups significantly improved the rest HR, the mean change of rest HR was significantly greater in MRV as compared to the RV (p < 0.001,  ŋ_p² = 0.47). The study revealed that an intensity-modified type of recreational volleyball, involving shorter breaks between rallies, improves cardiorespiratory fitness and health markers for men aged 25–55 years.

Anthropometric and performance profile of elite Gaelic football players comparing position and role

There is currently no information available on the variation in anthropometric and performance characteristics of starters and non-starters in elite Gaelic football. The aim of the current study was to determine if variations exist for elite male Gaelic football players with respect to position and playing role (starter or non-starter). One-hundred-and-sixty-two footballers from six elite teams underwent anthropometric and performance assessments. Players were categorised into six positional groups (goalkeeper, full back, half back, midfield, half forward and full forward) and two playing role groups (starter and non-starter). A significant position × role interaction was observed for Yo-YoIRT1 distance (p = 0.031, pη2 =  0.078), with starters covering a greater distance in all positions when compared to non-starters (all p < 0.05), except for half backs. Goalkeepers covered a significantly lower Yo-YoIRT1 distance compared to all other positions (p ≤ 0.001, pη2 = 0.35), while half backs completed a significantly greater distance compared to full backs (p = 0.014, pη2 = 0.35) and full forwards (p ≤ 0.001, pη2 = 0.35). Starters had a significantly greater CMJ height (p ≤ 0.001, pη2 = 0.082) and CMJ PP (p = 0.001, pη2 = 0.08) compared to non-starters. This research is the first of its kind within Gaelic football to provide anthropometric and performance values with respect to playing role. The data obtained may aid coaches to individualize training regimes to enhance role-specific preparation for competitive match-play.

Comparison of Physical Profiles of State-Level Netball Players by Position

Graham, S, Duthie, G, Aughey, R, and Zois, J. Comparison of physical profiles of state-level netball players by position. J Strength Cond Res 34(9): 2654-2662, 2020-Understanding the physical profiles of state-level netball athletes provides conditioning professionals with testing norms and an understanding of important capacities within particular positions. The purpose was to examine positional differences in physical capacities of state-level netball athletes. Forty-six state-level netball athletes completed physical capacity assessments in the second week of their preseason, over 2 seasons. Tests included stature, 20-m sprint (with 5 and 10 m splits), 505 change-of-direction, countermovement jump, single-leg bounding, and the Yo-Yo intermittent recovery test level one. A linear mixed-model with fixed and random effects was used in conjunction with magnitude-based inferences to determine meaningful differences with 90% confidence limits (CLs). Midcourt athletes were shorter in stature than shooters (effect size [ES]: 1.26, CL 0.88-1.63) and defenders (-2.58, -3.35 to -1.80). Midcourt athletes were faster than shooters and defenders in linear acceleration over 5 and 10 m distances and 505 change-of-direction (ES range: -0.34 to -0.59). Shooters presented poorer intermittent endurance than midcourt (-0.82, -1.34 to -0.31) and defenders (-0.56, -1.19 to 0.07). Defenders jumped higher than midcourt athletes (-0.56, -1.30 to 0.19) and shooters (-0.61, -1.18 to -0.04), and possessed greater bounding ability compared with shooters (ES range: -0.23 to -0.57). Midcourt athletes require a more holistic set of physical capacities including acceleration, change-of-direction, jumping, and intermittent endurance. For defender and shooter positions, results indicate physical requirements that may be more specific to their positions. Conditioning professionals can use these findings to target specific physical qualities to maximize position-specific performance.

Effects of football versus aerobic exercise training on muscle architecture in healthy men adults: a study protocol of a two-armed randomized controlled trial

BACKGROUND

Sports and exercise training can attenuate age-related declines in physical function. As people age, they suffer a progressive deterioration of overall muscle structure and function, such as muscle diameter, strength, mass, and power. Therefore, supporting older adults-aged 50 years and above-to continue being physically active is a very important factor. Several forms of exercise (strength, agility, endurance, balance, and flexibility) are recommended. In this regard, football has been repeatedly shown to be an integrative approach to promote measures of strength, endurance, and agility. However, there has been no previous randomized controlled trial that comparatively investigates the effects of football training versus traditional aerobic exercise training on muscle architecture and patella tendon properties in healthy community dwellers. The study protocol is designed to examine whether football differentially affects muscle thickness, muscle length, fascicle length, pennation angle, patella tendon length, and thickness compared to a workload matched traditional aerobic exercise training regimen.

METHODS

The study sample consists of 60 untrained but healthy men (50-60 years old), who will be randomly assigned (strata: age, activate) to two groups: football group (n = 30) and aerobic group (n = 30). The intervention will take place within 12 consecutive weeks, two times a week for 60 min each session. The football group will perform recreational football training as a large-sided game, whereas the aerobic group undergoes a running exercise. Both groups have the same external workload ranging between moderate and high exercise intensity. The outcome measure will be collected before and after the intervention period.

DISCUSSION

Findings of this study will provide insight into the effects of 24 sessions of both football and aerobic training program on the selected groups of men adults, including detecting their effects on the thigh muscle architecture.

TRIAL REGISTRATION

DRKS-German Clinical Trials Register, DRKS00020536 . Registered on 30 January 2020.

Yo-Yo Intermittent Recovery Level 1 Test for Estimation of Peak Oxygen Uptake: Use Without Restriction?

Purpose: This study analyzed the physiological response during Yo-Yo Intermittent Recovery Level 1 (YYIR1) test and re-test by in-field ergospirometry and time-series analyses of respiratory parameters. Methods: Ten moderately trained males (23.4 ± 2.01 years, VO_2peak= 56.81 ± 10.75 mL·kg^-1·min^-1) completed three running trials including two separate YYIR1 tests and an independent maximal performance running test with time-series analyses of gas exchange parameters. Physiological response was assessed during all tests by determination of blood lactate levels (including calculation of individual lactate threshold), heart rate, oxygen consumption and respiratory exchange ratio (RER). Results: Modeling of YYIR1 test mean VO₂ uptake kinetics over all participants revealed that VO₂ increased rapidly after the individual lactate threshold (11.49 ± 0.66 km∙h^-1 at 3.83 ± 0.42 mmol∙L^-1) was reached with ~95% VO_2peak at ~50% of the test duration (test, VO₂ ^50%= 95.17 ± 8.74% of VO_2peak; re-test, VO₂ ^50%= 96.78 ± 7.04% of VO_2peak). However, and despite identical YYIR1 test performance (1568 ± 364.6 m vs. 1568 ± 449.7 m, CV = 4.59%), mean VO_2peak during YYIR1 test was 8.81 ± 5.6% higher than YYIR1 re-test (p = .027). Importantly, correlation of VO_2peak with YYIR1 test performance was weak (R² = 0.28, p = .115). Conclusions: We conclude that the YYIR1 test should not be used to estimate VO_2peak. Further studies on direct determination of gas exchange parameters during different YYI test variants are warranted.

Test-Retest Reliability of the Yo-Yo Test: A Systematic Review

BACKGROUND

The Yo-Yo test is widely used both in the practical and research contexts; however, its true test-retest reliability remains unclear.

OBJECTIVE

The present systematic review aims to identify studies that have examined the test-retest reliability of the Yo-Yo test and summarize their results.

METHODS

A search of ten databases was performed to find studies that have investigated test-retest reliability of any variant of the Yo-Yo test. The COSMIN checklist was employed to assess the methodological quality of the included studies.

RESULTS

Nineteen studies of excellent or moderate methodological quality were included. When considering all variants of the Yo-Yo test, the included studies reported intra-class correlation coefficients for test-retest reliability ranging from 0.78 to 0.98 where 62% of all intra-class correlation coefficients were higher than 0.90, while 97% of intra-class correlation coefficients were higher than 0.80. The coefficients of variation ranged from 3.7 to 19.0%. Regardless of the variant of the test, the participants' familiarization with the test, and previous sport experience, the intra-class correlation coefficients generally seem high (≥ 0.90) and coefficients of variation low (< 10%).

CONCLUSIONS

The results of this review indicate that the Yo-Yo test (in all its variants) generally has good-to-excellent test-retest reliability. The evidence concerning reliability arises from 19 included studies that were of moderate or high methodological quality. Considering that most of the included studies examined the Yo-Yo intermittent recovery level 1 test while including Association Football players, more reliability studies examining Yo-Yo intermittent recovery level 2 test and Yo-Yo intermittent endurance level 1 and level 2 tests, and in the context of sports other than Association Football as well as in non-athletic populations, are required. Finally, future studies should explicitly state the type of intra-class correlation coefficient used for the reliability data analysis to allow for better between-study comparisons.

Classification of Players Across the Australian Rules Football Participation Pathway Based on Physical Characteristics

Haycraft, JAZ, Kovalchik, S, Pyne, DB, and Robertson, S. Classification of players across the Australian Rules football participation pathway based on physical characteristics. J Strength Cond Res XX(X): 000-000, 2020-This study investigated the utility of physical fitness and movement ability tests to differentiate and classify players into Australian Football League (AFL) participation pathway levels. Players (n = 293, age 10.9-19.1 years) completed the following tests; 5-m, 10-m, and 20-m sprint, AFL planned agility, vertical jump (VJ), running VJ, 20-m multistage fitness test (MSFT), and athletic ability assessment. A multivariate analysis of variance between AFL participation pathway levels was conducted, and a classification tree determined the extent to which players could be allocated to relevant levels. The magnitude of differences between physical fitness and movement ability were level-dependent, with the largest standardized effect size (ES) between Local U12, Local U14, and older levels for most physical fitness tests (ES: -4.64 to 5.02), except the 5-m and 10-m sprint. The 20-m, 5-m, AFL agility, 20-m MSFT, overhead squat, and running VJ (right) contributed to the classification model, with 57% overall accuracy reported (43% under cross-validation). National U16 players were easiest to classify (87%), while National U18 players were most difficult (0%). Physical fitness tests do not seem to differentiate between players after selection into AFL talent pathway levels. Other attributes (i.e., skill, psychological, and sociocultural) should be prioritized over physical fitness and movement attributes by selectors/coaches when considering selection of talented players.

Yo-Yo intermittent tests are a valid tool for aerobic fitness assessment in recreational football

PURPOSE

To examine the suitability of three versions and two levels of the Yo-Yo intermittent tests for assessing and tracking aerobic fitness status development in male recreational football players. Sixty-six untrained participants (age 39 ± 6 years, VO2max 41.2 ± 6.2 ml kg-1 min-1, body mass 81.9 ± 10.8 kg, height 173.2 ± 6.4 cm) partook in a 12-week recreational football training program. They were evaluated during the Yo-Yo intermittent endurance level 1 (YYIE1) and 2 (YYIE2) tests and the Yo-Yo intermittent recovery level 1 test (YYIR1), and during a treadmill test for VO2max assessment, at baseline. Thirty-two out of these 66 participants replicated all these tests at post-intervention. An additional group of 30 male age-matched recreational football players that afterwards started the 12-week recreational football program (age 39 ± 6 years, VO2max 45.3 ± 5.8 ml kg-1 min-1, body mass 82.5 ± 7.8 kg, height 172.8 ± 5.4 cm) was evaluated at baseline to test cross-validation.

RESULTS

The Yo-Yo tests showed very large associations with VO2max at baseline (r = 0.75-0.77; P < 0.0001) and at post-intervention (r = 0.76-0.82; P < 0.0005). Post-training, very large associations were found between YYIE2 performance and VO2max (r = 0.65, P < 0.0001). Cross-validation revealed small to large differences between the observed and estimated VO2max values (1.5-2.96 ml kg-1 min-1) with moderate typical error of estimation (7.9-8.7%) across the tests. Performance in the YYIE1, YYIE2 and YYIR1 tests of ≥ 1760, 480 and 600 m, respectively, indicated good to excellent VO2max values.

CONCLUSIONS

The Yo-Yo tests considered here showed robust and consistent criterion validity. The YYIE2 could be a more accurate option to track aerobic fitness development in recreational football players.

Evaluation of a Goalkeeper-Specific Adaptation to the Yo-Yo Intermittent Recovery Test Level 1: Reliability and Variability

Ehlert, AM, Cone, JR, Wideman, L, and Goldfarb, AH. Evaluation of a goalkeeper-specific adaptation to the Yo-Yo intermittent recovery test level 1: reliability and variability. J Strength Cond Res 33(3): 819-824, 2019-The Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) has been shown to be a reliable test with strong correlations to physical match performance in field soccer players. However, the YYIR1 has less goalkeeper (GK) specificity. Therefore, the purpose of this study was to evaluate the test-retest reliability of a goalkeeper-specific adaptation of the YYIR1 (YYIR1-GK). Sixteen National Collegiate Athletic Association (NCAA) collegiate GKs (8 men and 8 women) performed the YYIR1-GK test twice (>4 and <7 days apart) to determine its reliability and variability. Subjects were tested at the same time of day and in a controlled indoor environment. Heart rate using polar monitors and rating of perceived exertion were obtained at the end of each stage of the YYIR1-GK. Test-retest reliability for each test was assessed by Pearson correlations, intraclass correlation coefficient (ICC), and coefficient of variation (CV). The YYIR1-GK was shown to have a strong test-retest reliability and low variability for male (r = 0.981, ICC = 0.980, CV = 5.82%) and female (r = 0.969, ICC = 0.956, CV = 9.60%) NCAA GKs, respectively. Male GKs performed significantly more stages and therein covered a greater distance in the YYIR1-GK than the female GKs (p = 0.05). This study suggests that the YYIR1-GK is a consistent assessment of intermittent fitness with high test-retest reliability and low variability in male and female NCAA GKs. It is suggested that larger numbers of GKs of various skill levels be evaluated in the future.

Cardiorespiratory Fitness Predicts Greater Vagal Autonomic Activity in Drug Users Under Stress

While drug use has been shown to impair cardiac autonomic regulation, exercise might overcome some of the damage. Herein, we describe how individuals with substance use disorder (SUD) have their heart rate variability (HRV) and drug-related behaviors negatively affected in response to a stressor. However, we show how cardiorespiratory fitness may attenuate those impairments in autonomic control. Fifteen individuals with SUD were matched with 15 non-SUD individuals by age, weight, height, and fitness level, and had their HRV responses under stress induced by the Cold Pressor Test (CPT). The SUD group had lower mean of R-R intervals before and after the CPT when compared with the non-SUD group. In addition, in individuals with SUD, higher cardiorespiratory fitness level predicted greater vagal activity before, during, and after CPT. Moreover, for individuals with SUD, days of abstinence predicted greater mean of R-R intervals during recovery from the CPT. Finally, years of drug use negatively predicted mean of R-R intervals during recovery. Thus, our results suggest that chronic drug use impairs cardiac autonomic regulation at rest and after a physical stress. However, cardiorespiratory fitness might attenuate these impairments by increasing vagal autonomic activity.

Critical Speed as a Measure of Aerobic Fitness for Male Rugby Union Players

PURPOSE

To compare critical speed (CS) derived from all-out testing (AOT) for linear and shuttle running with metrics from a graded exercise test, the Yo-Yo Intermittent Recovery Test  Level 1 (YYIR1), and estimation of an 800-m-shuttle time trial.

METHODS

Twelve male rugby players completed a graded exercise test, the YYIR1, a linear AOT, shuttle AOTs of 25 and 50 m, and an 800-m-shuttle time trial consisting of 32 × 25-m shuttles.

RESULTS

Strong linear correlations were observed between maximum oxygen uptake ( V˙O2max ) and CS (m·s^-1) derived from the linear AOT (3.68 [0.62], r = .90, P < .01) and 50-m-shuttle AOT (3.19 [0.26], r = .83, P < .01). Conversely, V˙O2max showed lower correlations with speeds evoking CS from 25-m AOT (2.86 [0.18], r = .42, P = .18) and YYIR1 (4.36 [0.11], r = .55, P = .07). The 800-m time trial (213.58 [15.84] s) was best predicted using parameters from the 25-m AOT (r = .93, SEE = 6.60 s, P < .001).

CONCLUSIONS

The AOT is a valuable method of assessing performance-specific fitness, with CS from linear and 50-m-shuttle AOTs being strong predictors of V˙O2max , rivaling metrics from the graded exercise test. The YYIR1 offered limited utility compared with the AOT method.

A Reliable Testing Battery for Assessing Physical Qualities of Elite Academy Rugby League Players

Dobbin, N, Hunwicks, R, Highton, J, and Twist, C. A reliable testing battery for assessing physical qualities of elite academy rugby league players. J Strength Cond Res 32(11): 3232-3238, 2018-This study assessed the interday reliability of a testing battery for the assessment of physical qualities of rugby league players. Fifty players (age 17.1 ± 1.1 years; stature 181.3 ± 6.3 cm; and body mass 89.0 ± 11.6 kg) from 3 Super League academies participated in this study. Tests of countermovement jump performance, 10- and 20-m sprint performance, change of direction, medicine ball throw, and a modified Yo-Yo Intermittent Recovery Test Level 1 (prone Yo-Yo IR1) were completed on 3 separate occasions. Between-day intraclass correlation coefficient, typical error (TE), coefficient of variation, and the smallest worthwhile change (SWC) were calculated to determine the reliability and sensitivity of each measure. Individual tests (except medicine ball throw) were not systematically different between trials (p > 0.05), with an interday variability that was <10%. In all instances, the TE was larger than the calculated SWC change, although variability was less than that typically observed after a training intervention or specific training period (i.e. preseason). Using a magnitude-based inference approach, we present the required change for all performance tests to be 75% confident and the change is beneficial. This simple and time efficient testing battery is sufficiently reliable to detect previously observed changes in a range of physical qualities of rugby league players.

The Yo-Yo Intermittent Tests: A Systematic Review and Structured Compendium of Test Results

Background: Although Yo-Yo intermittent tests are frequently used in a variety of sports and research studies to determine physical fitness, no structured reference exists for comparison and rating of test results. This systematic review of the most common Yo-Yo tests aimed to provide reference values for test results by statistical aggregation of published data.

Methods: A systematic literature search for articles published until August 2017 was performed in MEDLINE, Web of Science, SPORTDiscus and Google Scholar. Original reports on healthy females and males ≥16 years were eligible for the analysis. Sub-maximal test versions and the Yo-Yo Intermittent Recovery Level 1 Children's test (YYIR1C) were not included.

Results: 248 studies with 9,440 participants were included in the structured analysis. The Yo-Yo test types most frequently used were the Yo-Yo Intermittent Recovery Level 1 (YYIR1, 57.7%), the Yo-Yo Intermittent Recovery Level 2 (YYIR2, 28.0%), the Yo-Yo Intermittent Endurance Level 2 (YYIE2, 11.4%), and the Yo-Yo Intermittent Endurance Level 1 (YYIE1, 2.9%) test. For each separate test, reference values (global means and percentiles) for sports at different levels and both genders were calculated.

Conclusions: Our analysis provides evidence that Yo-Yo intermittent tests reference values differ with respect to the type and level of sport performed.The presented results may be used by practitioners, trainers and athletes to rate Yo-Yo intermittent test performance levels and monitor training effects.

Incorporating perceptual decision-making training into high-intensity interval training for Australian football umpires

Existing methods for developing decision-making skill for Australian football umpires separate the physical and perceptual aspects of their performance. This study aimed to determine the efficacy of incorporating video-based decision-making training during high-intensity interval training sessions, specific for Australian football umpires. 20 amateur Australian football umpires volunteered to participate in a randomised control trial. Participants completed an 8-week training intervention in a conditioning only (CON; n=7), combined video-based training and conditioning (COM; n=7), or separated conditioning and video-based training (SEP; n=6) group. Preliminary and post-testing involved a Yo-Yo Intermittent Recovery Test (Yo-YoIR1), and 10x300m run test with an Australian football specific video-based decision-making task. Overall, changes in decision-making accuracy following the intervention were unclear between groups. SEP was possibly beneficial compared to COM in Yo-YoIR1 performance, whereas CON was likely beneficial compared to COM in 10x300m sprint performance. There was no additional benefit to completing video-based training, whether combined with, or separate to physical training, suggesting that this was not an optimal training method. For video-based training to be an effective decision-making tool, detailed feedback should be incorporated into training. It is recommended that longer conditioning and video-based training interventions be implemented to determine training effectiveness.

Reduced severity of lumbo-pelvic-hip injuries in professional Rugby Union players following tailored preventative programmes

OBJECTIVES

The aim of this study was to tailor lumbo-pelvic-hip (LPH) injury reduction programmes in professional rugby union players based on screening data and examine its effectiveness.

DESIGN

Prospective case controlled study.

METHODS

Twenty-eight professional rugby union players were screened pre- and immediately post- the YO-YO intermittent recovery level 1 test using six hip and groin strength tests (adductor squeeze at 0°, 60° and 90°, prone hip extension, abductor, adductor hand held dynamometry). The changes in hip and groin measures, were analysed using hierarchical cluster analysis. Three clusters emerged and a tailored LPH injury reduction programme was administered for each cluster. In addition, 22 players who were not involved in the initial testing received a generic LPH injury reduction programme and were used as the control. Seasonal information for LPH injury incidence, severity and prevalence were compared to the previous season.

RESULTS

The same number of injuries were observed when the prospective injury surveillance data was compared to the previous season, however a reduced injury severity (936days vs 468days), average severity (78±126days vs 42±37days) and prevalence (21% vs 19%) were found. Moreover, LPH injury severity for players who were prescribed a tailored injury reduction programme (209days) were 50days less than players given a generic LPH injury reduction programme (259days).

CONCLUSIONS

Our preliminary observations support the effectiveness of grouping players and tailoring intervention based on common group characteristics in reducing the severity of LPH injuries in professional Rugby Union.

Effects of Acutely Intermittent Hypoxic Exposure on Running Economy and Physical Performance in Basketball Players

Kilding, AE, Dobson, BP, and Ikeda, E. Effects of acutely intermittent hypoxic exposure on running economy and physical performance in basketball players. J Strength Cond Res 30(7): 2033-2042, 2016-The aim of this study was to determine the effect of short duration intermittent hypoxic exposure (IHE) on physical performance in basketball players. Using a single-blind placebo-controlled group design, 14 trained basketball players were subjected to 15 days of passive short duration IHE (n = 7), or normoxic control (CON, n = 7), using a biofeedback nitrogen dilution device. A range of physiological, performance, and hematological variables were measured at baseline, and 10 days after IHE. After intervention, the IHE group, relative to the CON group, exhibited improvements in the Yo-Yo intermittent recovery level 1 (+4.8 ± 1.6%; effect size [ES]: 1.0 ± 0.4) and repeated high-intensity exercise test performance (-3.5 ± 1.6%; ES: -0.4 ± 0.2). Changes in hematological parameters were minimal, although soluble transferrin receptor increased after IHE (+9.2 ± 10.1%; ES: 0.3 ± 0.3). Running economy at 11 km·h (-9.0 ± 9.7%; ES: -0.7 ± 0.7) and 13 km·h was improved (-8.2 ± 6.9%; ES: -0.7 ± 0.5), but changes to V[Combining Dot Above]O2peak, HRpeak, and lactate were unclear. In summary, acutely IHE resulted in worthwhile changes in physical performance tests among competitive basketball players. However, physiological measures explaining the performance enhancement were in most part unclear.

Reliability, Validity and Usefulness of 30-15 Intermittent Fitness Test in Female Soccer Players

PURPOSE: The aim of this study was to examine the reliability, validity and usefulness of the 30-15_IFT in competitive female soccer players. METHODS: Seventeen elite female soccer players participated in the study. A within subject test-retest study design was utilized to assess the reliability of the 30-15 intermittent fitness test (IFT). Seven days prior to 30-15_IFT, subjects performed a continuous aerobic running test (CT) under laboratory conditions to assess the criterion validity of the 30-15_IFT. End running velocity (V_CT and V_IFT), peak heart rate (HRpeak) and maximal oxygen consumption (VO_2max) were collected and/or estimated for both tests. RESULTS: V_IFT (ICC = 0.91; CV = 1.8%), HRpeak (ICC = 0.94; CV = 1.2%), and VO_2max (ICC = 0.94; CV = 1.6%) obtained from the 30-15_IFT were all deemed highly reliable (p > 0.05). Pearson product moment correlations between the CT and 30-15_IFT for VO_2max, HRpeak and end running velocity were large (r = 0.67, p = 0.013), very large (r = 0.77, p = 0.02) and large (r = 0.57, p = 0.042), respectively. CONCLUSION: Current findings suggest that the 30-15_IFT is a valid and reliable intermittent aerobic fitness test of elite female soccer players. The findings have also provided practitioners with evidence to support the accurate detection of meaningful individual changes in V_IFT of 0.5 km/h (1 stage) and HRpeak of 2 bpm. This information may assist coaches in monitoring "real" aerobic fitness changes to better inform training of female intermittent team sport athletes. Lastly, coaches could use the 30-15_IFT as a practical alternative to laboratory based assessments to assess and monitor intermittent aerobic fitness changes in their athletes.

Locomotor, Heart-Rate, and Metabolic Power Characteristics of Youth Women's Field Hockey: Female Athletes in Motion (FAiM) Study

PURPOSE

The purpose of this study was to quantify the locomotor, heart-rate, and metabolic power characteristics of high-level youth female field hockey matches.

METHOD

Players from the U21 and U17 Canadian women's national teams were monitored during a 4-match test series using Global Positioning System technology. Position (forward, midfielder, defender) and age-group (U21, U17) comparisons were made using 2-way analyses of variance.

RESULTS

Forwards played 12 min to 22 min fewer than midfielders and defenders and consequently had lower amounts of total, low-intensity, and moderate-intensity distances. Yet, forwards covered similar amounts of high-intensity running and sprinting distances despite the deficit in playing time. Only 10% to 15% of total distance was characterized by high-intensity running and sprinting, yet the majority of time was spent above 90% maximum heart rate. The distances in high, elevated, and maximal metabolic power categories were greater for U21 than U17 players. Yo-Yo Intermittent Recovery Test performance was related to high-intensity running and maximal metabolic power distance.

CONCLUSIONS

The current findings highlight positional specificity as well as developmental gaps between age groups for youth female field hockey matches. These match characteristics should be used to assist in establishing appropriate training strategies through the developmental pathway and to assist player achievement to higher standards.

When the going gets tough: Mental toughness and its relationship with behavioural perseverance

OBJECTIVES

This study examined the association between self-reported mental toughness and behavioural perseverance among a sample of male Australian footballers in a naturalistic context.

DESIGN

Cross-sectional field study, with the multistage 20m shuttle run test (MST) employed as a proxy for behavioural perseverance.

METHODS

330 male Australian footballers aged between 15 and 18 years (M=16.86; SD=.71) with between 2 and 14 years playing experience (M=9.32; SD=2.51) participated. Initially, footballers completed a mental toughness questionnaire, before having their height and body mass measurements taken. Subsequently, a performance testing session was completed, which included the 20m sprint, Australian football-specific agility run, vertical jump, and the MST. Bayesian estimation was employed to allow for the simultaneous examination of existing findings with our new data in a way that provides an automatic meta-analysis of evidence in this area.

RESULTS

The analysis indicated a 95% probability that the association between mental toughness and behavioural perseverance lies between .14 and .34, even when controlling for other factors known to influence MST performance, including age, height, body mass, and years playing experience.

CONCLUSIONS

Taken together with previous research, these findings support the theoretical proposition that persistence, effort or perseverance represents a behavioural signature of mental toughness.

The Yo-Yo intermittent recovery test level 1 is reliable in young high-level soccer players

The aim of the study was to investigate test reliability of the Yo-Yo intermittent recovery test level 1 (YYIR1) in 36 high-level youth soccer players, aged between 13 and 18 years. Players were divided into three age groups (U15, U17 and U19) and completed three YYIR1 in three consecutive weeks. Pairwise comparisons were used to investigate test reliability (for distances and heart rate responses) using technical error (TE), coefficient of variation (CV), intra-class correlation (ICC) and limits of agreement (LOA) with Bland-Altman plots. The mean YYIR1 distances for the U15, U17 and U19 groups were 2024 ± 470 m, 2404 ± 347 m and 2547 ± 337 m, respectively. The results revealed that the TEs varied between 74 and 172 m, CVs between 3.0 and 7.5%, and ICCs between 0.87 and 0.95 across all age groups for the YYIR1 distance. For heart rate responses, the TEs varied between 1 and 6 bpm, CVs between 0.7 and 4.8%, and ICCs between 0.73 and 0.97. The small ratio LOA revealed that any two YYIR1 performances in one week will not differ by more than 9 to 28% due to measurement error. In summary, the YYIR1 performance and the physiological responses have proven to be highly reliable in a sample of Belgian high-level youth soccer players, aged between 13 and 18 years. The demonstrated high level of intermittent endurance capacity in all age groups may be used for comparison of other prospective young soccer players.

Are the Yo-Yo intermittent recovery test levels 1 and 2 both useful? Reliability, responsiveness and interchangeability in young soccer players

Abstract The aim of this study was to compare the reliability, internal responsiveness and interchangeability of the Yo-Yo intermittent recovery test level 1 (YY1), level 2 (YY2) and submaximal YY1 (YY1-sub). Twenty-four young soccer players (age 17 ± 1 years; height 177 ± 7 cm; body mass 68 ± 6 kg) completed each test five times within pre- and in-season; distances covered and heart rates (HRs) were measured. Reliability was expressed as typical error of measurement (TEM) and intraclass correlation coefficient (ICC). Internal responsiveness was determined as effect size (ES) and signal-to-noise ratio (ES_TEM). Interchangeability was determined with correlation between training-induced changes. The TEM and ICC for distances in the YY1 and YY2 and for HR in YY1-sub were 7.3% and 0.78, 7.1% and 0.93 and 2.2% and 0.78, respectively. The ESs and ES_TEMs were 0.9 and 1.9 for YY1, 0.4 and 1.2 for YY2 and -0.3 and -0.3 for YY1-sub. Correlations between YY1 vs. YY2 and YY1-sub were 0.56 to 0.84 and -0.36 to -0.81, respectively. Correlations between change scores in YY1 vs. YY2 were 0.29 and -0.21 vs. YY1-sub. Peak HR was higher in YY1 vs. YY2. The YY1 and YY2 showed similar reliability; however, they were not interchangeable. The YY1 was more responsive to training compared to YY2 and YY1-sub.

Characteristics of high-level youth soccer players: variation by playing position

The present study aimed to investigate positional differences in 744 high-level soccer players, aged 8 to 18 years. Players were assigned to six age groups (U9-U19) and divided into four playing positions (goalkeeper (GK), defender (DEF), midfielder (MF) and attacker (ATT)). MANOVA and effect sizes were used to examine anthropometrical and functional characteristics between all positions in all age groups. The main findings of the study were that GKs and DEFs were the tallest and heaviest compared with MFs and ATTs in all age groups. Further, between U9-U15, no significant differences in functional characteristics were found, except for dribbling skill, which MFs performed the best. In the U17-U19 age groups, ATTs seemed to be the most explosive (with GKs), the fastest and the more agile field players. These results suggest that inherent physical capacities (i.e., speed, power, agility) might select players in or reject players from an attacking position, which is still possible from U15-U17. Apparently, players with excellent dribbling skills at younger age are more likely to be selected to play as a MF, although, one might conclude that the typical physical characteristics for different positions at senior level are not yet fully developed among young soccer players between 8 and 14 years.

Modeling developmental changes in yo-yo intermittent recovery test level 1 in elite pubertal soccer players

PURPOSE

To model the development of soccer-specific aerobic performance, assessed by the Yo-Yo Intermittent Recovery Test Level 1 in 162 elite pubertal soccer players, age 11-14 y at baseline.

METHODS

Longitudinal multilevel modeling analyses comprised predictors related to growth (chronological age, body size [height and weight] and composition [fat mass, fat-free mass]), and motor coordination [3 KÖrperkoordination Test für Kinder subtests: jumping sideways, moving sideways, backward balancing] and estimated biological-maturation groups (earliest [<percentile 33] and latest maturers [>percentile 66]).

RESULTS

The best-fitting model on soccer-specific aerobic performance could be expressed as -3639.76 + 369.86 × age + 21.38 × age² + 9.12 × height - 29.04 × fat mass + 0.06 × backward balance. Maturity groups had a negligible effect on soccer-specific aerobic performance (-45.32 ± 66.28; P > .05).

CONCLUSION

The current study showed that the development of aerobic performance in elite youth soccer is related to growth and muscularity and emphasized the importance of motor coordination in the talent-identification and -development process. Note that biological maturation was excluded from the model, which might endorse the homogeneity in estimated biological-maturation status in the current elite pubertal soccer sample.

A caffeinated energy drink improves jump performance in adolescent basketball players

This study aimed at investigating the effects of a commercially available energy drink on shooting precision, jump performance and endurance capacity in young basketball players. Sixteen young basketball players (first division of a junior national league; 14.9 ± 0.8 years; 73.4 ± 12.4 kg; 182.3 ± 6.5 cm) volunteered to participate in the research. They ingested either (a) an energy drink that contained 3 mg of caffeine per kg of body weight or (b) a placebo energy drink with the same appearance and taste. After 60 min for caffeine absorption, they performed free throw shooting and three-point shooting tests. After that, participants performed a maximal countermovement jump (CMJ), a repeated maximal jumps test for 15 s (RJ-15), and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Urine samples were obtained before and 30 min after testing. In comparison to the placebo, the ingestion of the caffeinated energy drink did not affect precision during the free throws (Caffeine = 70.7 ± 11.8 % vs placebo = 70.3 ± 11.0 %; P = 0.45), the three-point shooting test (39.9 ± 11.8 vs 38.1 ± 12.8 %; P = 0.33) or the distance covered in the Yo-Yo IR1 (2,000 ± 706 vs 1,925 ± 702 m; P = 0.19). However, the energy drink significantly increased jump height during the CMJ (38.3 ± 4.4 vs 37.5 ± 4.4 cm; P < 0.05) mean jump height during the RJ-15 (30.2 ± 3.6 vs 28.8 ± 3.4 cm; P < 0.05) and the excretion of urinary caffeine (1.2 ± 0.7 vs 0.1 ± 0.1 μg/mL; P < 0.05). The intake of a caffeine-containing energy drink (3 mg/kg body weight) increased jump performance although it did not affect basketball shooting precision.

Reliability and validity of the Yo-Yo intermittent recovery test level 1 in young soccer players

The present study investigated the test-retest reliability from the Yo-Yo IR1 (distance and heart rate responses), and the ability of the Yo-Yo IR1 to differentiate between elite and non-elite youth soccer players. A total of 228 youth soccer players (11-17 years) participated: 78 non-elite players to examine the test-retest reliability within 1 week, added with 150 elite players to investigate the construct validity. The main finding was that the distance covered was adequately reproducible in the youngest age groups (U13 and U15) and highly reproducible in the oldest age group (U17). Also, the physiological responses were highly reproducible in all age groups. Moreover, the Yo-Yo IR1 test had a high-discriminative ability to distinguish between elite and non-elite young soccer players. Furthermore, age-related standards for the Yo-Yo IR1 established for elite and non-elite groups in this study may be used for comparison of other young soccer players.

The yo-yo intermittent recovery test in junior basketball players according to performance level and age group

The aim of this study was to evaluate the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) ability to discriminate between elite, subelite junior basketball players, and a group of nonathletic healthy male athletes at 3 different age groups (U-14 to U-17). In a cross-sectional design, 119 age-matched participants spread over 3 groups, elite (n = 46), subelite (n = 42) junior basketball players, and nonathletic healthy male athletes (n = 31), were evaluated over a 5-week period. The participants undertook 2 familiarization trials of the Yo-Yo test performance and 3 test sessions on an indoor basketball court. When controlling for the effect of the participants' body mass, the results showed that elite athletes had a significantly higher Yo-Yo performance compared with the subelite athletes (1,271 ± 385 vs. 861 ± 428 m; p < 0.0017; effect size [ES] 1.0 ± 0.35) and the nonathletic group (1,271 ± 385 vs. 738 ± 345 m; p < 0.0017; ES 1.45 ± 0.38). No statistical differences (p > 0.0017; ES from 0.02 to 0.39) were noted between participants' performance levels across age groups. Typical between-performance levels and -age groups differences in the Yo-Yo IR1 were observed. However, when controlling for the effect of the participants' body mass, this study demonstrates that the Yo-Yo test is accurate only to discriminate elite junior basketball players but cannot be used to differentiate the basketball-specific aerobic performance for age.

The relationship between the yo-yo tests, anaerobic performance and aerobic performance in young soccer players

The purposes of this study were to determine the relationship between performance in the Yo-Yo intermittent recovery test level 1 (YIRT1), the Yo-Yo intermittent recovery test level 2 (YIRT2) and the Yo-Yo endurance test (continuous) (YET) with maximal oxygen uptake (VO₂max) and Wingate anaerobic performance (WaNT) test results in young soccer players (age 15.00 ± 0.0 years, body height 176.3 ± 4.2 cm and body mass 68.1 ± 3.6 kg). An ergospirometry device was used during the treadmill test (TRT) to determine VO₂max. At the end of the study, significant differences were found between the Yo-Yo tests and TRT in terms of HRmax (TRT = 195,92, YIRT1 = 197,83, YIRT2 = 198,5 YET = 198) (p > 0.05). While there were moderate correlations between VO₂max and YIRT 1–2 performances (respectively, r = 0.56, r = 0.53), there was only a weak relationship between VO₂max and YET performance (r = 0.43) (distance covered). There were also moderate significant negative correlations between performance in the YIRT2 and peak power measured in the WaNT (r = −0.55), although there were no significant correlations between performance in the three tests and average power. A moderate negative correlation was found between performance in the YIRT2 and Fatigue index (FI) (r = −0,66). In conclusion, the YIRT2 may be a more suitable field test for determining both aerobic and anaerobic performance in soccer players.

Direct validity of the yo-yo intermittent recovery test in young team handball players

The aim of this study was to examine the possible association between Yo-Yo intermittent recovery test level 1 performance (distance covered, Yo-Yo IR1) and match activities (direct validity) in young male team handball players. Eighteen young male players (age 14.3 +/- 0.5 years, body mass 64 +/- 28.7 kg, height 174 +/- 6 cm, body fat 11.2 +/- 3.9%) took part in this study. Players' match activities were videotaped during an experimental tournament (6 games/player) and analyzed using a computerized system. Games and Yo-Yo IR1 heart rates (HRs) (short-range telemetry, HR) and blood lactate concentrations ([la]b) were assessed throughout and at selected times of the games, respectively. Peak Yo-Yo IR1 HR was assumed as representative of individual maximal HR (HRmax). Mean and peak game HRs were 174 +/- 3 and 198 +/- 2 b.min, which corresponded to 87 and 99% of HRmax, respectively. Yo-Yo IR1 performance (1,831 +/- 373 m) was significantly related (r = 0.88, p < 0.01) to total game distance (1,921 +/- 325 m). Post-game (9.2 +/- 2.3 mmol.L) and Yo-Yo IR1 (8.8 +/- 1.6 mmol.L) [la]b were significantly related (r = 0.51, p < 0.05). These findings demonstrated the direct validity of Yo-Yo IR1. Consequently, Yo-Yo IR1 test may be considered as a team handball test relevant for the assessment of intermittent high-intensity endurance in young male team handball players.

Physiological determinants of Yo-Yo intermittent recovery tests in male soccer players

The physiological determinants of performance in two Yo-Yo intermittent recovery tests (Yo-YoIR1 and Yo-YoIR2) were examined in 25 professional (n = 13) and amateur (n = 12) soccer players. The aims of the study were (1) to examine the differences in physiological responses to Yo-YoIR1 and Yo-YoIR2, (2) to determine the relationship between the aerobic and physiological responses to standardized high-intensity intermittent exercise (HIT) and Yo-Yo performance, and (3) to investigate the differences between professional and amateur players in performance and responses to these tests. All players performed six tests: two versions of the Yo-Yo tests, a test for the determination of maximum oxygen uptake (V(O)(2)(max)), a double test to determine V(O)(2) kinetics and a HIT evaluation during which several physiological responses were measured. The anaerobic contribution was greatest during Yo-YoIR2. V(O)(2)(max) was strongly correlated with Yo-YoIR1 (r = 0.74) but only moderately related to Yo-YoIR2 (r = 0.47). The time constant (tau) of V(O)(2) kinetics was largely related to both Yo-Yo tests (Yo-YoIR1: r = 0.60 and Yo-YoIR2: r = 0.65). The relationships between physiological variables measured during HIT (blood La(-), H(+), HCO(3) (-) and the rate of La(-) accumulation) and Yo-Yo performance (in both versions) were very large (r > 0.70). The physiological responses to HIT and the tau of the V(O)(2) kinetics were significantly different between professional and amateur soccer players, whilst V(O)(2)(max) was not significantly different between the two groups. In conclusion, V(O)(2)(max) is more important for Yo-YoIR1 performance, whilst tau of the V(O)(2) kinetics and the ability to maintain acid-base balance are important physiological factors for both Yo-Yo tests.

Comparison of progressive maximal swimming tests in elite female water polo players

PURPOSE

To compare the Multistage Shuttle Swim Test (MSST), Water Polo Intermittent Shuttle Test (WIST) and 5 200 m Incremental Swimming Test (IST) responses in elite female water polo players.

METHODS

Fourteen Australian Women's National Water Polo Squad members performed the MSST and WIST, and 13 players from a National Water Polo League club performed the IST, MSST and WIST on separate occasions (no goalkeepers were involved). Peak heart rate, blood lactate and ratings of perceived exertion were obtained for all tests. Expired air was collected following all tests for the National League players.

RESULTS

The National Squad players scored significantly better (ie, distance covered) in the MSST and WIST than the National League players (effect sizes=1.60 to 1.79, P<.001). The MSST and WIST scores were significantly correlated (r=.80 to 0.88, P<.001). The MSST scores were significantly correlated with peak oxygen uptake (VO2peak; mL.kg(-1).min(-1)) obtained for all tests (r=.58 to 0.59, P<.05). In contrast, there were no significant correlations between the WIST scores and VO2peakobtained for any of the tests (r=.43 to 0.52, P>.05). Differences in VO2peakfor the IST, MSST and WIST were nonsignificant (P>.05).

CONCLUSIONS

The MSST and WIST can discriminate players of different competition standards. The MSST can be used to estimate a player's aerobic fitness and peak heart rate. The WIST appears to better mimic the intermittent activity pattern of the game, but its application to female players, to assess maximal intermittent endurance swimming performance, requires further evaluation.

The Yo-Yo Intermittent Recovery Test (Level 1) to discriminate elite junior Australian football players

The Yo-Yo Intermittent Recovery (IR) Test is currently used to assess endurance performance in team sport athletes. However, to date, no data has been presented on its application to an elite junior Australian football (AF) playing group. Therefore, the aim of this study was to evaluate the Yo-Yo Intermittent Recovery Test Level 1 (IR1) ability to discriminate between junior AF players at two different playing standards and a group of non-athletic healthy males. Sixty age matched participants (16.6+/-0.5 years) spread over three groups (20 per group): elite junior footballers; sub-elite junior footballers; and non-athletic healthy males participated in this study. Participants undertook a single Yo-Yo test performance on an indoor basketball court for each group. A one-way ANOVA with Scheffe's post hoc analysis revealed the elite junior footballers covered a significantly greater total distance (p<0.001) and completed a significantly greater number of high-intensity efforts (p<0.001) in comparison to their sub-elite counterparts, whilst both AF groups performed significantly better (p<0.001) than the non-athletic healthy males. This study demonstrates the ability of the Yo-Yo IR1 to discriminate endurance performance between elite and sub-elite AF players, whilst further distinguishing AF players from a non-athletic healthy control group.

Efficacy of interval-based training on conditioning of amateur field hockey players

This research aimed to critically examine the effectiveness of a time-limited and distance-regulated interval training program on subelite field hockey players. Subjects comprised 22 women (26.1 +/- 4.5 years, 62.8 +/- 7.4 kg, 1.7 +/- 0.9 m) and 22 men (22.1 +/- 3.2 years, 74.9 +/- 5.4 kg, 1.8 +/- 0.5 m) field hockey players. Performance tests included a standard 20-m multiple-stage shuttle run (MSSR), a 1000-m repeated-effort (x3) time trial (RTT), and a 100-m repeated-effort (x3) shuttle run (RSR) in an ascending pyramid order. The training program was administered separately to the women and men after a traditional, single-peak, 4-week mesocycle, with the fourth week for recovery. Training consisted of an average total sprint distance of 3000 m per session during a 20-week data collection period, with testing administered pre and post. Initial athlete profiling showed a significant (p < 0.05) gender difference on all performance tests. The MSSR results were 8.6 +/- 2.5 (range 6.7-10.7) and 12.1 +/- 2.4 (10.2-13.5) women and men, respectively. The RTT and RSR times for women and men were 5:34 +/- 0:30 seconds (4:31-6:21), 5:14 +/- 0:30 seconds (4:27-6:02), 4:12 +/- 0:13 seconds (3:50-4:36), and 4:06 +/- 0:13 seconds (3:47-6:02), respectively. After 20 weeks of training, a small to moderate effect size (ES) was calculated for the women's (n = 12) MSSR (ES = 0.74) and RSR (ES = 0.50) results. A distinct improvement in the MSSR resulted after training for men (n = 16), with a moderate ES (1.34). In contrast, completion times in RSR were marginally reduced, with a small ES (0.49). The findings demonstrate that a 3000-m interval-based conditioning program, when conducted in conjunction with normal-skill game play training, can lead to significant improvements in player conditioning during a competitive season. Future research should employ modified performance tests that more accurately reflect the nature of the game.