Yo-Yo Intermittent Recovery Test Level Research Articles

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.

Effect of the Energy Drink “Red Bull” on the Amateur Football Players’ Aerobic and Anaerobic Performances

This study was conducted to investigate effect of 250 ml of Red Bull energy drink consumed 60 minutes before an intensive exercise on aerobic and anaerobic performances of amateur football players (subjects were PE students).In this study, a crossover research design was applied. Test subjects were divided into two groups, namely A and B. In the first experiment, group A was provided Red Bull, and group B was given apple juice (placebo) and tests were carried out. In the second experiment, the same tests were carried out by interchanging the drinks provided to the groups previously. The aerobic performance assesment was performed with the Yo-Yo Intermittent Recovery Test (Level 1) while the anaerobic performance assesment was carried out with the Wingate test. The differences between the groups were analyzed by Wilcoxon Signed-Ranks Test, and the significance level was accepted as p&lt;0.05.As a result of the tests applied to Red Bull and Placebo groups; there was seen no significance difference between the maximal VO2 values of the groups (Red Bull, x̅=49.50±3.14 ml/kg/min; Placebo, x̅=48.81±3.07 ml/kg/min, z=-1.244, p&gt;0.214). Additionally, according to the Wingate test results, no significant difference was found between the Red Bull and Placebo groups. (Peak Power: Red Bull x̅=877.56±164.82 W, Placebo x̅=841.67±162.23 W (z=-1.48, p&gt;0.13), Average Power: Red Bull x̅=616.70±99.17 W, Placebo x̅=603.69±92.05 W (z=-1.59, p&gt;0.11), Time at Peak Power: Red Bull x̅=2.21±0.95 sec, Placebo x̅=1.97±1.00 sec (z=-0.29, p&gt;0.76).As a result, it was observed that the performances of amateur footballers did not show a significant increase when Red Bull energy drink was consumed one hour before Yo-Yo Intermittent Recovery Test (Level 1) and Wingate Anaerobic Power Test. Considering unconscious consumption of caffeinated drinks and its possible side effects, it is not recommended for athletes who are not used to it.

In-season adaptations to intense intermittent training and sprint interval training in sub-elite football players.

This study investigated the in-season effect of intensified training comparing the efficacy of duration-matched intense intermittent exercise training with sprint interval training in increasing intermittent running performance, sprint ability, and muscle content of proteins related to ion handling and metabolism in football players. After the first two weeks in the season, 22 sub-elite football players completed either 10weeks of intense intermittent training using the 10-20-30 training concept (10-20-30, n=12) or sprint interval training (SIT, n=10; work/rest ratio: 6-s/54-s) three times weekly, with a ~20% reduction in weekly training time. Before and after the intervention, players performed a Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and a 30-m sprint test. Furthermore, players had a muscle biopsy taken from the vastus lateralis. Yo-Yo IR1 performance increased by 330m (95%CI: 178-482, P≤0.01) in 10-20-30, whereas no change was observed in SIT. Sprint time did not change in 10-20-30 but decreased by 0.04second (95%CI: 0.00-0.09, P≤0.05) in SIT. Muscle content of HADHA (24%, P≤0.01), PDH-E1α (40%, P≤0.01), complex I-V of the electron transport chain (ETC) (51%, P≤0.01) and Na+ , K+ -ATPase subunits α2 (33%, P≤0.05) and β1 (27%, P≤0.05) increased in 10-20-30, whereas content of DHPR (27%, P≤0.01) and complex I-V of the ETC (31%, P≤0.05) increased in SIT. Intense intermittent training, combining short sprints and a high aerobic load, is superior to regular sprint interval training in increasing intense intermittent running performance during a Yo-Yo IR1 test and muscle content of PDH-E1α and HADHA in sub-elite football players.

Low Doses of Caffeine: Enhancement of Physical Performance in Elite Adolescent Male Soccer Players.

Context: High doses of ∼6mg·kg-1 body mass have improved performance during intermittent running, jumping, and agility protocols. However, there are sparse data on low doses of caffeine, especially in elite adolescent soccer players. Methods: A total of 15 elite youth soccer players (177.3 [4.8]cm, 66.9 [7.9]kg, and 16 [1]y) participated in the study, consuming 1, 2, or 3 mg·kg-1 caffeine in a gelatin capsule or a 2-mg·kg-1 placebo in a single-blind, randomized, crossover study design. Testing consisted of a 20-m sprint, arrowhead agility (change of direction [CoD] right or left), countermovement jump (CMJ), and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1). Postexercise CMJ performance was assessed as participants exited the Yo-Yo IR1. Data were analyzed using a Bayesian multilevel regression model to provide explained variance and probabilities of improvement (P = %). Results: Compared with placebo, 3 mg·kg-1 caffeine presented the highest probabilities of change across a range of tests (mean[SD], P = %). Times for 20-m sprint were 3.15 (0.10)s vs 3.18 (0.09)s (P = 73%), CoD-right times were 8.43 (0.24)s vs 8.55 (0.25)s (P = 99%), CoD-left times were 8.44 (0.22)s vs 8.52 (0.18)s (P = 85%), Yo-Yo IR1 distance was 2440 (531)m vs 2308 (540)m (P = 15%), and preexercise CMJ height was 41.6 (7.2)cm vs 38 (8.5)cm (P = 96%). Postexercise CMJ was higher with 3mg·kg-1 than with placebo (42.3 [8]cm vs 36.6 [8]cm; P = 100%). Doses of 1 or 2 mg·kg-1 caffeine also demonstrated the ability to enhance performance but were task dependent. Conclusion: Low doses of caffeine improve performance but are dose and task dependent. A dose of 3 mg·kg-1 caffeine improved performance across the majority of tests with potential to further improve postexercise CMJ height.

Reliability of aerobic and anaerobic field tests in in measuring athletes’ performances: A statistical approach on a cohort of 100 subjects

To determine the statistical relationships among different consolidated performance tests (Yo-Yo, jump, sprint and agility), and the Powersprint™ device, an isotonic equipment, usually used to increase the muscular strength of athletes, used here as performance test. One hundred individuals were involved in the tests (16 females and 84 males). Ninety-five subjects were practicing different field sports, whereas 3 female and 2 male subjects were inactive. Gender, height and body mass were recorded. Participants completed the following tests: Squat Jump, Counter Movement Jump, 10 m sprint, 15 m sprint, Change of Direction, Yo-Yo Intermittent Recovery Test level 1 and PowerSprint 3.0™. Results of this experiment highlighted that PowerSprint 3.0™ is positively and significantly correlated with Squat Jump, Counter Movement Jump, 10 m sprint, 15 m sprint, Change of Direction, Yo-Yo Intermittent Recovery Test level 1. Additionally, the principal component analysis, as expected, was able to neatly differentiates between male, female and inactive subjects. The selected tests appeared particularly effective in giving information about athlete performances in soccer. Performances measured with the PowerSprint 3.0™ positively and significantly correlated with jumps, COD, sprint and YYIR1 tests. This is an indication of the possible use of this light, inexpensive and portable instrument for measuring athlete performances and checking the effectiveness of training programs.

Relationships between Different Field Test Performance Measures in Elite Goalball Players.

Goalball is a Paralympic sport involving people with visual impairment. Little is known about the physical fitness of elite players of this sport, as previous studies only evaluated body composition and aerobic capacity. Thus, the aim of this study was to describe the performance of elite goalball players in different physical tests and to look for relationships between them. Eleven elite Brazilian goalball players, seven males and four females, were evaluated for body composition, maximal handgrip isometric force (MHGF), countermovement jump (CMJ), throwing velocity (TV) and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Players produced 41.54 ± 8.41 kgf in MHGF, 34.81 ± 7.2 cm in CMJ, 14.21 ± 1.89 m∙s−1 in TV, and 505 ± 313 m in Yo-Yo IR1, with an estimated maximum oxygen consumption (VO2max) of 40.64 ± 2.63 mL∙kg−1∙min−1. Most performance tests exhibited moderate to high correlations among them, while the percentage of body fat correlated with both the CMJ and Yo-Yo IR1 results. The current study reveals that CMJ could be a valuable monitoring tool as it was correlated with all other performance tests. The highest correlation observed was with TV (r = 0.754; p < 0.05), which is a key capacity in goalball. Moreover, high levels of body fat could be detrimental to anaerobic performance.

Anthropometry, Physical and Movement Features, and Repeated-sprint Ability in Soccer Players.

This study aimed to evaluate the associations of anthropometry, functional movement patterns (FMP) and physical performance characteristics with repeated-sprint ability (RSA) in male youth soccer players. Thirty six athletes (ages 16.6±0.5 years, BMI 22.0±1.3 kg/m2) completed the RSA test and other physical tests including countermovement jump with (CMJA) and without the help of arms (CMJ), 10-m and 20-m straight-line sprints, Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo), and functional movement screen (FMS). In addition, a battery of anthropometric variables was measured. RSA performance components such as best time (BT), mean time (MT) and sprint decrement were calculated. Results showed that measures of physical performance derived from horizontal plane in 10-m and 20-m sprints, were more strongly associated (p<0.01) with RSA performance than those obtained with CMJ or CMJA (p<0.05). High correlations (p<0.01) were found between MT, BT and Yo-Yo distance (r=-0.79, r=-0.67, respectively), as well as with FMS scores (r=-0.68, r=-0.58, respectively). Anthropometric measures, such as fat mass, upper fat area, thigh fat area, calf muscle area, and endomorphy were associated with RSA components (p<0.05). Predictors for the RSA performance identified in the stepwise multivariate analysis included Yo-Yo distance, time in sprints, FMP, and calf muscle area.

Effect of air pollution and time of day on performance, heart rate hematological parameters and blood gases, following the YYIRT-1 in smoker and non-smoker soccer players

Summary Objectives This study aimed to investigate the effect of air pollution and time of day on performance, heart rate hematological parameters and blood gases, following the Yo-Yo intermittent recovery test level 1 in smoker and non-smoker soccer players. Methods Twenty-two soccer players were divided into two groups; (smoker: n = 11) and (non-smoker: n = 11). Each participant completed the test at 08:00 h and 18:00 h in two different areas (i.e. Polluted and non-polluted area) with a recovery period ≥ 72 h in between. Results Our results showed that at rest, both groups revealed a significant diurnal variation on oral temperature, heart rate, and white blood cell count with an acrophase at 18:00 h and on red blood cells with a significant decrease at 18:00 h in the two areas (P Conclusion Intermittent recovery test under high concentrations of pollutants leads a significant alteration of performance and physiological parameters in healthy and smoker athletes especially in the evening. Furthermore, results from the field may help to guide athletes and contribute to public health recommendations on exercise and pollution.

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.

Differences in Physical Performance According to the Competitive Level in Futsal Players.

The purpose of the present study was to describe performance in acceleration capacity, change of direction ability, vertical jump, horizontal jump, repeated sprint ability, and endurance (Yo-Yo Intermittent Recovery Test Level 1) in futsal players, and analyze the differences according to competitive categories or levels. The total sample (n = 40) was divided into three groups depending on the category in which the participants competed: Second Division B (n = 15), Third Division (n = 12) and juniors (n = 13). All the tests were performed with participants’ regular competition shoes and on the usual playing surface, in an indoor pavilion with a floating wood floor. The results of the study did not show significant differences in acceleration capacity (5 and 15 m) or change of direction ability among the different categories. In contrast, significant differences were found among the categories with regard to horizontal jump and vertical jump capacity (p < 0.05); but not in all the variables analyzed. Performance in repeat sprint ability varied significantly among the different categories in 30 m (p < 0.01) but not in 5 m (p > 0.05). The distance covered in the Yo-Yo Intermittent Recovery Test Level 1 by the Second Division B and the Third Division groups was greater than that covered by the junior group. In the light of these results repeated sprint ability and aerobic endurance could be two discriminating qualities of the competitive level among different futsal categories.

Relationship Between Tactical Performance, Somatic Maturity and Functional Capabilities in Young Soccer Players.

The aim of the study was to investigate the relationship between tactical performance, somatic maturity, and functional capabilities in young soccer players. Study participants were 48 soccer players (14.80 ± 1.5 years) belonging to an extension project at the State University of Maringa - Brazil. Anthropometric measurements of body mass, body height, and sitting height were carried out. The number of years to peak height velocity (PHV) was used as an index of maturation. Evaluations of functional fitness included the following tests: sit-and-reach, Yo-Yo Intermittent Recovery Test Level 1, handgrip test, modified abdominal test, and vertical jumps (Counter Movement Jump and Jump Squat). Tactical performance was assessed through the System of Tactical Assessment in Soccer (FUT-SAT). Multiple Linear Regression models were used to estimate the relative contributions of functional and maturational capacities to tactical performance. The results indicated weak associations between the tactical performance indices and somatic maturity, functional capacity, and anthropometric attributes (r < 0.40). The Yo-Yo Test contributed to 36% of the defensive tactic performance variation in the under 13 category. These results suggest that the level of maturity, growth status, and functional fitness have limited impact on tactical performance of young soccer players.

Relationships between physical qualities and key performance indicators during match-play in senior international rugby union players.

The use of physical tests to profile physical capabilities, and provide training direction to athletes is common practice. Likewise, in professional team sports, notational analysis codes the key contributions of each player during competition. Limited studies have however investigated relationships between physical capabilities and key performance indicators (KPIs) of rugby union match-play. Elite professional players, categorised as forwards (n = 15) or backs (n = 14), from an international rugby union squad (n = 29) undertook assessments of isometric mid-thigh pull (IMTP), bilateral and unilateral countermovement jumps (CMJ) and drop jumps (DJ; from 40 and 20 cm, respectively), and assessment of acceleration (10 m), a 5 m weighted sled drive, and a Yo-Yo intermittent recovery test level 1 (Yo-Yo IRTL1). Game statistics of the same players from 92 matches (~23 matches per player) during the 2014–15 season were analysed for effort and performance-based metrics. For forwards, Yo-Yo IRTL1 correlated significantly with; number of tackles made (r = 0.717), first three players at a ruck in both attack (r = 0.568) and defence (r = 0.581), number of effective rucks (r = 0.630), total possessions (r = 0.522), passes made (r = 0.651), percentage of carries over the gainline (r = 0.610), effective ruck success (r = 0.600), tackle success (r = 0.540), and the number of turnovers made (r = 0.518). Drop jump performance in forwards was associated with; the number of clean breaks (r = 0.558), dominant collisions (r = 0.589), and offloads (r = 0.594). For backs, the sled-drive test correlated with; number of carries (r = -0.751), first three players at an attacking ruck (r = -0.613), effective attacking rucks (r = -0.584), number of dominant collisions (r = -0.792) and offloads (r = -0.814). Likewise, for backs, IMTP peak force was related to; the number of possessions (r = 0.793), passes made (r = 0.792), effective attacking ruck percentage (r = 0.628), and the number of offloads (r = 0.621) whilst relative peak force correlated with; the percentage of carries over the gainline (r = 0.533), percent tackle success (r = 0.603) and effective attacking ruck percentage (r = 0.584). Regression analyses highlighted that only a small number of variables (i.e., carries, tackles, attacking and defensive first three at ruck) returned practically achievable changes (<20%) in physical qualities. In spite of this, and while leaving scope identification of further physical and/or performance predictors, greater strength, power and intermittent running performance were positively related to match-derived KPIs during competition. This may provide a basis for better integrating the strategies used by physical and technical performance-focused coaching staff to improve key performance indicators, and thus match performance, of rugby union players.

Physical Characteristics of Elite Youth Female Soccer Players Characterized by Maturity Status.

Emmonds, S, Scantlebury, S, Murray, E, Turner, L, Robsinon, C, and Jones, B. Physical characteristics of elite youth female soccer players characterized by maturity status. J Strength Cond Res 34(8): 2321-2328, 2020-The purpose of this study was to investigate the influence of maturity status on the physical characteristics of youth female soccer players. One hundred fifty-seven players from 3 elite soccer academies in England completed assessments of anthropometry, strength (isometric midthigh pull), lower-body power (countermovement jump [CMJ]), aerobic capacity (Yo-Yo intermittent recovery test level 1), change of direction (CoD: 505-left/right), and speed (10 and 30 m). Each player was classified into 1 of 6 maturity groups based on their estimated years from peak height velocity (YPHV). Magnitude-based inferences were used to assess for the practical significance between consecutive groups. Speed, CoD time, CMJ, and aerobic capacity were all possibly most likely better in more mature players. However, there was a likely difference in relative peak force between maturity groups -0.5 YPHV (27.13 ± 4.24 N·Kg) and 0.5 YPHV (24.62 ± 3.70 N·Kg), which was associated with a likely difference in 10-m sprint time (-0.5 YPHV: 2.00 ± 0.12 vs. 0.5 YPHV 2.08 ± 0.16 seconds) and unclear changes in CMJ and CoD time. Findings provide novel comparative data for this cohort relative to maturity status and can be used by strength and conditioning coaches to inform the design of training programs for youth female soccer players. Strength and conditioning coaches should be aware that youth female soccer players may experience a decrease in relative strength around peak height velocity, which may impact upon the speed, CoD time, and CMJ of players.

Effects of Caffeinated Gum on a Battery of Soccer-Specific Tests in Trained University-Standard Male Soccer Players.

The purpose of this study was to determine whether caffeinated gum influenced performance in a battery of soccer-specific tests used in the assessment of performance in soccer players. In a double-blind, randomized, crossover design, 10 male university-standard soccer players (age: 19 ± 1 years, stature: 1.80 ± 0.10m, body mass: 75.5 ± 4.8kg) masticated a caffeinated (200mg; caffeine) or control (0mg; placebo) gum on two separate occasions. After a standardized warm-up, gum was chewed for 5min and subsequently expectorated 5min before players performed a maximal countermovement jump, a 20-m sprint test, and the Yo-Yo Intermittent Recovery Test Level 1. Performance on 20-m sprints was not different between trials (caffeine: 3.2 ± 0.3s, placebo: 3.1 ± 0.3s; p = .567; small effect size: d = 0.33), but caffeine did allow players to cover 2.0% more distance during Yo-Yo Intermittent Recovery Test Level 1 (caffeine: 1,754 ± 156m, placebo: 1,719 ± 139m; p = .016; small effect size: d = 0.24) and increase maximal countermovement jump height by 2.2% (caffeine: 47.1 ± 3.4cm, placebo: 46.1 ± 3.2cm; p = .008; small effect size: d = 0.30). Performance on selected physical tests (Yo-Yo Intermittent Recovery Test Level 1 and countermovement jump) was improved by the chewing of caffeinated gum in the immediate period before testing in university-standard soccer players, but the sizes of such effects were small. Such findings may have implications for the recommendations made to soccer players about to engage with subsequent exercise performance.

Effects of short-term in-season break detraining on repeated-sprint ability and intermittent endurance according to initial performance of soccer player.

To better understand the detraining effects in soccer, the purpose of the study was to analyse if performance level of soccer players modulate repeated-sprint ability (RSA) and intermittent endurance changes during 2-weeks of detraining (i.e., in-season break). Seventeen professional and sixteen young elite soccer players of two different teams performed, before and after 2-weeks of detraining, the RSA test and the Yo-Yo Intermittent Recovery Test, level 1 (YYIR1). Before detraining, professional players perform better (p < 0.05) RSA best time (RSAbest) than young players. A decrease (p < 0.05) in RSAbest, RSA total time (RSAtotal) and mean time (RSAmean) performance was observed in both teams, without changes in RSA fatigue index (Sdec). No significant changes in distance covered during YYIR1 was observed in any team. Before detraining, faster players from both teams (FG) (following the median split technique, soccer players with RSAbest ≤ 3.95 s) performed better (p < 0.01) in RSAtotal, RSAmean and RSAbest, but worse (p < 0.01) in Sdec. Although FG and the slower players (SG, RSAbest > 3.95 s) showed a worse (p < 0.05) RSAtotal, RSAbest and RSAmean performance after detraining (ES = 1.5, 1.4 and 2.9; ES = 0.6, 1.2 and 0.6; for FG and SG, respectively), the deterioration was greater in the FG for RSAbest (p < 0.05) and RSAtotal (ES = 1.46). After detraining, FG improved (p < 0.05) Sdec performance. In conclusion, a 2-week in-season break (detraining) period induced a worse RSA, with no effect on intermittent endurance in professional and elite young soccer players, with greater detrimental effects on RSAtotal and RSAbest in FG. In addition, Sdec does not seem to be sensitive to changes in RSA after a 2-week in-season break.

Positional Anthropometric and Performance Profile of Elite Gaelic Football Players

Shovlin, A, Roe, M, Malone, S, and Collins, K. Positional anthropometric and performance profile of elite gaelic football players. J Strength Cond Res 32(8): 2356-2362, 2018-The aim of the current investigation was to evaluate the variation in the anthropometric and performance characteristics of elite Gaelic football players with respect to position. One hundred forty-eight elite Gaelic footballers underwent anthropometric (height, body mass, sum of 7 skinfolds, and % adipose tissue) and performance (counter movement jump [CMJ] height, CMJ peak power, CMJ relative peak power, squat jump [SJ] height, SJ peak power, SJ relative peak power, 5-, 10-, and 20-m sprint times, and Yo-Yo Intermittent Recovery Test Level 2 [Yo-YoIRT2]) during "the early in-season" phase. Data were split into 5 positional groups (full back, half back, midfield, half forward, and full forward). Higher adipose tissue percentage estimate was observed in full forwards when compared with the half backs (p = 0.001), midfielders (p = 0.035), and half forwards (p = 0.021). Full forwards had significantly greater SJ (p = 0.036) and CMJ (p = 0.013) when compared with the midfielders with no other positional differences observed. No significant variation in sprint times was observed across the positions. When Yo-YoIRT2 was considered, full forwards and full backs completed significantly lower distances compared with the middle 3 positional lines of half backs, midfielders, and half forwards (p = 0.00). The current study is the first to provide normative data for anthropometric and performance values of elite Gaelic football players which in turn can be used by coaches to generate appropriate training regimes to maximize position-specific preparation for competitive match-play.

An examination of a modified Yo-Yo test to measure intermittent running performance in rugby players

This study examined how starting each shuttle in the prone position altered the internal, external and perceptual responses to the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1). Using a randomized crossover design, 17 male rugby players completed the Yo-Yo IR1 and prone Yo-Yo IR1 on two separate occasions. External loads (via microtechnology), , heart rate (HR) and rating of perceived exertion (RPE) were measured at 160, 280 and 440 m (sub-maximal) and when the test was terminated (peak). The pre-to-post change in blood lactate concentration (Δ[La]b) was determined for both tests. All data were analysed using effect sizes (ES) and magnitude-based inferences. Between-trial differences (ES ± 90% CL) indicated that total distance was most likely lower (−1.87 ± 0.19), whereas other measures of peak external load were likely to very likely higher during the prone Yo-Yo IR1 (0.62–1.80). Sub-maximal RPE was likely to most likely higher (0.40–0.96) and peak RPE very likely higher (0.63 ± 0.41) in the prone Yo-Yo IR1. The change in [La]b was likely higher after the prone Yo-Yo IR1. Mean HR was possibly lower at 440 m (−0.25 ± 0.29) as was peak HR (−0.26 ± 0.25) in the prone Yo-Yo IR1. , and were likely to very likely higher at 280 and 440 m (ES = 0.36–1.22), while peak values were possibly to likely higher (ES = 0.23–0.37) in the prone Yo-Yo IR1. Adopting a prone position during the Yo-Yo IR1 increases the internal, external and perceptual responses, placing greater emphasis on metabolically demanding actions typical of rugby.

Concurrent Validity of a Rugby-Specific Yo-Yo Intermittent Recovery Test (Level 1) for Assessing Match-Related Running Performance.

Dobbin, N, Highton, J, Moss, SL, Hunwicks, R, and Twist, C. Concurrent validity of a rugby-specific Yo-Yo intermittent recovery test (level 1) for assessing match-related running performance. J Strength Cond Res 35(1): 176-182, 2021-This study investigated the concurrent validity of a rugby-specific high-intensity intermittent running test against the internal, external, and perceptual responses to simulated match play. Thirty-six rugby league players (age 18.5 ± 1.8 years; stature 181.4 ± 7.6 cm; body mass 83.5 ± 9.8 kg) completed the prone Yo-Yo Intermittent Recovery Test (Yo-Yo IR1), of which 16 also completed the Yo-Yo IR1, and 2 × ∼20 minute bouts of a simulated match play (rugby league match simulation protocol for interchange players [RLMSP-i]). Most likely reductions in relative total, low-speed and high-speed distance, mean speed, and time above 20 W·kg-1 (high metabolic power [HMP]) were observed between bouts of the RLMSP-i. Likewise, rating of perceived exertion (RPE) and percentage of peak heart rate (%HRpeak) were very likely and likely higher during the second bout. Pearson's correlations revealed a large relationship for the change in relative distance (r = 0.57-0.61) between bouts with both Yo-Yo IR1 tests. The prone Yo-Yo IR1 was more strongly related to the RLMSP-i for change in repeated sprint speed (r = 0.78 cf. 0.56), mean speed (r = 0.64 cf. 0.36), HMP (r = 0.48 cf. 0.25), fatigue index (r = 0.71 cf. 0.63), %HRpeak (r = -0.56 cf. -0.35), RPEbout1 (r = -0.44 cf. -0.14), and RPEbout2 (r = -0.68 cf. -0.41) than the Yo-Yo IR1, but not for blood lactate concentration (r = -0.20 to -0.28 cf. -0.35 to -0.49). The relationships between prone Yo-Yo IR1 distance and measures of load during the RLMSP-i suggest that it possesses concurrent validity and is more strongly associated with measures of training or match load than the Yo-Yo IR1 using rugby league players.

Reliability of heart rate responses both during and following a 6 min Yo-Yo IR1 test in highly trained youth soccer players

ABSTRACTPurpose: To examine the reliability of heart rate (HR) measures obtained during a 6-min Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1), and following a 3-min passive recovery, within a group of highly trained youth soccer playersMethods: Eight players completed three separate 6-min Yo-Yo IR1 tests, with a passive recovery, over a 2-week period. Measures of absolute heart rate (bpm) and relative HR (%HRmax) were obtained at the 3rd and 6th min of the test, with measures relative to the end HR (%HRend) 10, 20, 30, 60, 90, and 180 s, during the 3-min passive recovery. Variability in HR measures were assessed across successive trials (trial 1 vs. 2 and trial 2 vs. 3) and across all three trials, using the intraclass correlation coefficient (ICC), coefficient of variation (CV) and typical error (TE).Results: HR measures obtained during the 6-min Yo-Yo IR1 test displayed good levels of reliability (ICC: 0.95–0.98, CV: 1.1–1.3% and TE: 0.96–2.44). Results, display a potential learning effect, with lower levels of variability between trial 2 and trial 3. Examination of %HRend obtained during the passive 3-min recovery demonstrated an increased variance, as the passive-recovery period progressed.Conclusion: The 6-min Yo-Yo IR1 test presents a novel and potentially practical approach to regularly assessing youth soccer players’ physical response to intermittent exercise. Practitioners and researchers should, however, consider the need for appropriate familiarisation when undertaking this test.

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

ABSTRACTObjectives: We examined: (1) relationships among sub-maximal heart rate (sub-maxHR) following 4 minutes of the Yo-Yo intermittent recovery test level 1 (IR1) and maximal-effort performance (distance covered at volitional exhaustion), (2) test re-test reliability of sub-maxHR, and (3) whether changes in maximal-effort Yo-Yo performance are related with changes in sub-maxHR in professional rugby league players.Methods: Yo-Yo IR1 performances of 32 players were assessed before and after 28.5 ± 6.8 days of pre-season training. Relationships between sub-maxHR and maximal-effort Yo-Yo performance, and changes in maximal-effort performance and sub-maxHR were compared.Results: Maximal-effort Yo-Yo IR1 performance and sub-maxHR correlated negatively (r = −0.73, CI −0.85 to −0.55, very large). Coefficient of variation (CV) of sub-maxHR was 2.4% (CI 2.0−3.3%), worthwhile changes of small (0.7 [CI 0.5−1.0%]), moderate (2.1 [CI 1.6−3.0%]) and large (4.3 [CI 3.3−6.1%]) were identified. Training-induced changes in sub-maxHR and Yo-Yo IR1 performance displayed a negative correlation (r = −0.57, CI −0.74 to −0.33, large).Conclusions: sub-maxHR has a very large negative relationship with maximal-effort Yo-Yo IR1 performance. Training-induced changes in sub-maxHR demonstrated a large negative relationship with changes in Yo-Yo IR1 performance. The CV and worthwhile changes can determine meaningful variations in sub-maxHR in professional rugby league players.