Yo-Yo IR1 Performance Research Articles

Anaerobic and Aerobic Metabolic Capacities Contributing to Yo-Yo Intermittent Recovery Level 2 Test Performance in Australian Rules Footballers.

This study aimed to identify the aerobic and anaerobic metabolic performance capacities contributing to Yo-Yo Intermittent Recovery level 2 (Yo-Yo IR2) test performance. Nineteen recreational Australian footballers completed a Yo-Yo IR2 test, and on another day a treadmill peak oxygen uptake (VO2peak) and maximal accumulated oxygen deficit test in a randomised counter-balanced order. The maximal accumulated oxygen deficit (MAOD) procedures included 5 × 5 min sub-maximal continuous runs at progressively higher speeds whilst VO2 was recorded; thereafter, speed was incrementally increased to elicit VO2peak. After 35 min of rest, participants ran at a speed equivalent to 115% of VO2peak until exhaustion, at which point expired air was collected to determine maximal accumulated oxygen deficit. Relationships between variables were assessed using Pearson's correlation and partial correlations. Maximum aerobic speed, relative intensity, and VO2peak were significantly correlated with Yo-Yo IR2 performance. High Yo-Yo IR2 performers also had higher MAS, relative intensity, and VO2peak levels. However, when higher maximum aerobic speed, relative intensity, and VO2peak were controlled for each other and analysed independently, neither maximal aerobic speed nor VO2peak correlated with Yo-Yo IR2 performance. Yo-Yo IR2 performance is the result of a complex interaction between several variables. Training programs should primarily focus on improving VO2peak, maximal aerobic speed, and relative intensity to optimize Yo-Yo IR2 test performance.

Effects of low-volume court-based sprint interval training on anaerobic capacity and sport-specific performance in competitive tennis players

Sprint interval training (SIT) is a potent exercise strategy to enhance athletes’ anaerobic capacity in a time-efficient manner. This study aimed to investigate the impact of low-volume, court-based SIT on the anaerobic capacity and sport-specific performance in competitive tennis players. Twenty-four competitive collegiate tennis players were randomly assigned to either the SIT group (n = 12; three sessions per week of court-based repeated-sprint training) or the traditional endurance training (ET) group (n = 12; three sessions per week of 45-min continuous treadmill running, n = 12) for a 6-weeks intervention. Baseline and post-intervention assessments included the Wingate Anaerobic Test, elimination rate of blood lactate (BLAer), tennis-specific repeated sprint ability (RSA), and the Yo-Yo Intermittent Recovery Test Level 2 (YoYo-IR2). The results showed that SIT group demonstrated significant improvements in peak and average power during the Wingate test (p = 0.07; p < 0.001), along with a notable increase in YoYo-IR2 performance (7.8% increase, p = 0.04). Significant decreases were observed in both mean (5.1% decrease, p = 0.02) and sum RSA time (5.2% decrease, p = 0.02) in the tennis-specific RSA assessments. Additionally, the SIT group showed significantly higher effective training time and TRIMP in the 90–100% HRmax zone compared to the ET group (p < 0.01). This study underscores the potential benefits of low-volume, court-based SIT in enhancing anaerobic capacity and sport-specific performance in competitive tennis players, in comparison to traditional ET.

Exploring the relationship between caffeine metabolism-related CYP1A2 rs762551 polymorphism and team sport athlete status and training adaptations

BackgroundThis study aimed to achieve a dual objective: to compare the frequencies of CYP1A2 rs762551 genotypes between team sport athletes and a control group, and to determine the association between the rs762551 polymorphism and changes in physical performance after a six-week training program among elite basketball players.MethodsThe study encompassed an analysis of 504 individuals, comprising 320 athletes and 184 controls. For the Turkish cohort, DNA was isolated using the buccal swab method, and genotyping was conducted using the KASP technique. Performance assessments included the Yo-Yo IR2 and 30 m sprint tests. For Russian participants, DNA samples were extracted from peripheral blood, a commercial kit was used for DNA extraction, and genotyping of the rs762551 polymorphism was conducted using DNA microarray.ResultNotably, a statistically significant linear decline in the prevalence of the CC genotype was observed with ascending levels of athletic achievement within team sports (sub-elite: 18.0%, elite: 8.2%, highly elite: 0%; p = 0.001). Additionally, the CA genotype was the most prevalent genotype in the highly elite group compared to controls (80.0% vs. 45.1%, p = 0.048). Furthermore, statistically significant improvements in Yo-Yo IR2 performance were noted exclusively among basketball players harboring the CA genotype (p = 0.048).ConclusionsThe study’s findings indicate that the rs762551 CC genotype is a disadvantage in elite team sports, whereas the CA genotype provides an advantage in basketball performance.

Follow-Up Weekly Training Distribution and Accumulated Internal Load Effects on Young Football Players' Well-Being, Physical Fitness, and Technical Performance.

This study aimed to quantify the relationships among internal training load, wellness, physiological, isokinetic profile, and technical performance and assessed changes before and after a six-week pre-season structured combining physical fitness, small-sided-game and skill-based training program in young soccer players. Forty-five national-level young male soccer players (16.8 ± 0.9 years) were evaluated. There were no significant correlations between the wellness index and the physiological, isokinetic, or specific soccer skill parameters. Moderate correlations were observed between fatigue and stress (r = 0.47, moderate, p < 0.01), fatigue and average muscle soreness (r = 0.38, moderate, p = 0.01), and a large correlation between average stress and muscle soreness (r = 0.53, large, p < 0.01) were presented. All physiological, isokinetic, and technical parameters improved after a six-week pre-season training program (0.1 to -61.0%). Significant alterations in the physiological domain were observed after a six-week period, particularly in the fatigue index of the Bangsbo sprint test, YO-YO IR1 performance, and YO-YO peak La- (p < 0.01; -61.0%, 25.3%, and -19.8%, respectively). As such, the implementation of structured training and the monitoring of stress responses can lead to appropriate adaptation and balancing in the psychological and physical well-being of young national-level soccer players, particularly in the pre-season period.

High-Intensity Interval Training Combined with High-Load Strength Training Improves Aerobic Fitness, Match Goals and Match Result during the In-Season Period in Under-19 Soccer Players.

This study compared the effects of adding a weekly session of either strength training followed by high-intensity interval training (HIIT) or high load plyometric training followed by small-sided games (SSG) on aerobic fitness, goals scored and conceded, and match results. Twenty-nine players from two youth elite teams competing in an under 19 (U19) first division league took part in the study. Of those, 16 players from one team followed the HIIT program (age: 17.8 ± 0.6 years) and 13 players from the other team trained once a week, following the SSG program (age: 18.0 ± 0.6 years). The training intervention lasted for 11 weeks and was applied once per week. For the HIIT team it included high-load strength training (80-95% of 1 RM) followed by high-intensity intermittent running, whereas for the SSG team (n = 13) it included plyometric exercises followed by SSG. Aerobic fitness was assessed before and after the intervention, while goals scored and conceded, as well as match results during the intervention period, were compared with the 11-week period preceding it. Only the HIIT team improved Yo-Yo IR2 performance (running distance: from 902.5 ± 147.5 to 1092.5 ± 155.8 m, p < 0.001) while there was no change for the SSG group. Moreover, during the 11-week intervention, the HIIT team improved the number of goals scored in the last 30 min of the game compared with the pre-intervention period (0.36 ± 0.50 to 1.27 ± 0.90 per match, p < 0.05) and the scored vs. conceded goals were higher in the second half (1.36 ± 1.03 vs. 0.27 ± 0.47, p < 0.05). No significant differences were found for these parameters in the SSG team. Regarding match result, the HIIT team increased the proportion of wins from 5 wins in 11 matches (or 45%) in the pre-intervention period to 9 wins in 11 matches (or 82%) during the intervention period, while this profile remained unchanged for the SSG team. In conclusion, the present study demonstrated that the HIIT program performed once per week was superior to SSG as it improves aerobic fitness, scored and conceded goals, and match result during the in-season period.

Small-Sided Games versus Continuous Endurance Training in Female Handball Players.

The main aim of the study was to compare the training methods of continuous endurance training versus handball small-sided games (SSGs) in female handball players during the preseason. Eighteen female handball players from a first league in the Czech Republic voluntarily participated in the study. They were divided into two groups (the SSG group [n = 9; age: 21.22 ± 3.03 years] and a running group (RG) [n = 9; age: 23.78 ± 3.77 years]). Both groups continued regular preseason training for six weeks. The SSG group played two small-sided games per week (a total of 12 games during the monitoring period) in their training sessions during the monitored six-week period. The RG ran twice per week, participating in continuous endurance training in the 12 training sessions during the monitored six-week period. Fitness tests (pretest/posttest) were performed prior to the six weeks of intervention and one week afterwards. The order of the fitness tests in sequence was as follows: 20-m and 30-m sprints, a Modified Agility T test (MAT), a Standing Long-Jump Test, ball-throwing velocity, and a Yo-Yo Intermittent Test level 1. In the SSG group, there was a significant improvement in the T test (p = 0.034), ball-throwing velocity (p = 0.019), and the Yo-Yo IR1 (p = 0.003) performance. The RG showed a significant improvement in the Standing Long-Jump Test (p = 0.049), ball-throwing velocity (p = 0.003), and the Yo-Yo IR1 (p = 0.003) performance. In conclusion, the SSGT method had a positive effect on female players' MAT, ball-throwing velocity and YoYo IR1 results, and the CERT method had a significant effect only on the YoYo IR1 results. Handball SSGs are a more suitable training method due to exercise specificity.

Effects of Concurrent High-Intensity and Strength Training on Muscle Power and Aerobic Performance in Young Soccer Players during the Pre-Season.

The aim of the present study was to evaluate two different intervention programs applied during a 4-week pre-season period. Twenty-nine players participated in this study and were divided into two groups. One group (BallTrain, n = 12, age: 17.8 ± 0.4 years, body mass: 73.9 ± 7.6 kg, height: 178 ± 0.1 cm, body fat: 9.6 ± 5.3%) performed a higher percentage of aerobic training with ball and strength training using plyometrics and exercises with body weight. The other group (HIITTrain, n = 17, age: 17.8 ± 0.7 years, body mass: 73.3 ± 5.0 kg, height: 179 ± 0.1 cm, body fat: 8.0 ± 2.3%) trained with high-intensity interval training (HIIT) without the ball and performed resistance training with weights in the same session. Both groups trained for strength (two times/week) and performed aerobic-anaerobic fitness without the ball, passing games, and tactical and small-sided games. Lower limb power (CMJ) and aerobic fitness (Yo-Yo intermittent recovery test level 1-IR1) were evaluated before and after the four-week training program. Yo-Yo IR1 performance was improved in both groups, but the improvement was greater for the HIITTrain than BallTrain group (468 ± 180 vs. 183 ± 177 m, p = 0.07). CMJ showed a non-significant improvement in the BallTrain group (5.8 ± 8.8%, p = 0.16), but it decreased by 8.1 ± 9% (p = 0.001), in the HIITTrain group. In conclusion, we have shown that a short pre-season period of training results in improvements in aerobic fitness in both groups, with high-intensity interval training showing superior adaptations than training with the ball. However, CMJ performance was reduced in this group, possibly suggesting higher fatigue levels and overload, and/or showing the effects of concurrent HIITTrain and strength training in soccer.

Single and Serial Carbohydrate Mouth Rinsing Do Not Improve Yo-Yo Intermittent Recovery Test Performance in Soccer Players.

Carbohydrate (CHO) mouth rinsing seems to improve performance in exercises lasting 30-60min. However, its effects on intermittent exercise are unclear. It is also unknown whether serial CHO mouth rinses can promote additional ergogenic effects when compared with a single mouth rinse. The aim of this study was to evaluate the effect of single and serial CHO mouth rinses on Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) performance in soccer players. In a randomized, crossover, double-blind, placebo-controlled design, 12 male (18.9 ± 0.5years) soccer players performed eight serial mouth rinses under three different conditions: placebo solution only (noncaloric juice), seven placebo mouth rinses plus a single CHO mouth rinse (8% maltodextrin), or eight CHO mouth rinses (8-CHO). Following the final mouth rinse, individuals performed the Yo-Yo IR1 test to evaluate the maximal aerobic endurance performance measured via total distance covered. There were no differences in Yo-Yo IR1 performance between sessions (p = .32; single CHO mouth rinse (8% maltodextrin): 1,198 ± 289m, eight CHO mouth rinses: 1,256 ± 253m, placebo: 1,086 ± 284m). In conclusion, single and serial CHO mouth rinsing did not improve performance during the Yo-Yo IR1 for soccer players. These data suggest that CHO mouth rinsing is not an effective ergogenic strategy for intermittent exercise performance irrespective of the number of rinses.

Fitness and Performance Testing of Male and Female Beach Soccer Players-A Preliminary Investigation.

Purpose: This study aimed to compare performance on sand and a firm surface and to describe the physical capacity of male and female beach soccer players.Methods: Sixty-six male and 29 female competitive beach soccer players voluntarily participated in this study. Firstly, within-subjects test scores were compared to scores on a firm surface (criterion validity; n = 15 men) and reconducted on a second occasion (reliability; n = 51 men). Secondly, the best score on sand was retained to compare test performance between ages (classified as below 20, 20–30, and above 30 years) and sexes. Performance assessments included sprint time over 5 and 15 m (once on a firm surface and twice on sand), standing long jump (SLJ, once on a firm surface and twice on sand) and Yo-Yo intermittent recovery level 1 (Yo-Yo IR1, once on a firm surface and once on sand; only data for men were available).Results: Five-m sprint and Yo-Yo IR1 performance on sand were not correlated to performance on a firm surface (P > 0.05). Test-retest reliability was acceptable for the 15-m sprint and SLJ tests (ICC > 0.90; CV < 5%). Performance in 15-m sprint and maximal sprinting speed were moderately lower in male players aged above 30 years. compared to players aged below 30 years (d = 0.35–0.42; P < 0.05). Irrespective of the age group, weight-bearing power-based performance mass was moderately to very largely higher in male players than in female players (d = 0.42–0.88; P < 0.05).Conclusions: The lack of a consistent relationship between performance on sand and on a firm surface might indicate the need to develop specific test batteries for sand-based athletes. Age-related differences in physical performance were evident only in sprint capacity. Further studies are warranted to elucidate our preliminary findings and to develop the sand specific tests.

The effect of isolated or combined small-sided games and speed endurance training on physical performance parameters in young soccer players

The purpose of this study was to investigate the effects of six weeks of small-sided games (SSG), speed endurance (SER) and combined SSG and SER (CT) training programs on sprint, repeated sprint, Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and level 2 (Yo-Yo IR2) performance in young soccer players. Forty-one elite young soccer players (body height: 174.0 ± 7.5 cm, body weight: 59.7 ± 9.5 kg, age: 14.6 ± 0.5 years, training age: 7.4 ± 0.6 years) underwent anthropometric measurements before performing 10m and 30m sprint tests, repeated sprint tests, and Yo-Yo IR1 and Yo-Yo IR2. The players were then divided into four groups: the SSG group (SSG; n=11), the SER group (SER; n=10), the CT group (CT; n=11), and the control group (CG; n=9). All groups performed training for six weeks on two days out of the five training days the participants were undertaking. There was a statistically significant increase in the Yo-Yo IR1 and Yo-Yo IR2 test performances of players in SSG, SER and CT groups (p&amp;lt;.05). In addition, players in these groups showed significantly higher percentage increases in Yo-Yo IR2 test performance compared to the CG. The CT group also had a statistically significant increase in Yo-Yo IR1 test performance compared to the CG (p&amp;lt;.05). In conclusion, while this study shows that SSG and SER training can be used for physical performance development in isolation or in combination, coaches and sports scientists are advised to choose combined training to use training time more efficiently.

Anthropometric and physical fitness profiles of Tunisian female soccer players: Associations with field position

Background: There is a lack of descriptive data available regarding the characteristics of female soccer players from the African continent or the Arab world. Objective: This study investigated the anthropometric and physical fitness profiles of Tunisian female soccer players in relation to field position. Methods: In all, 75 Tunisian sub-elite female soccer players, with an average of 4.3 &#177; 1.6 years of playing experience, including goalkeepers (GK; n = 11), central defenders (CD; n = 13), external defenders (ED; n = 15), central midfielders (CM; n = 10), external midfielders (EM; n = 14), and attackers (AT; n = 12), underwent anthropometric evaluations (body height, body mass, and body fat percentage) and physical fitness tests (flexibility, countermovement jump [CMJ], 20-m sprint, and Yo-Yo intermittent recovery test level 1 [YoYoIR1]). Results: GK had significantly higher body mass (67.3 &#177; 2.4 kg), body height (169.3 &#177; 1.7 m) and fat percentage (24 &#177; 2.6%) compared to all field positions. AT were significantly faster (3.64 &#177; 0.10 s) than GK (3.75 &#177; 0.09 s) in the 20-m sprint (p &lt; .01), but there were no significant differences among the other field positions. GK had a significantly lower Yo-YoIR1 performance (625 &#177; 84 m) than other field position players (p &lt; .001), but no significant difference was found among other field positions. GK and AT showed significantly better CMJ performance (GK: 31.3 &#177; 2.6 cm, AT: 30.4 &#177; 2.4 cm) compared to other groups. GK had higher flexibility (21.6 &#177; 2.7 cm in the the sit-and-reach test) than all other positions (p &lt; .05), but no significant difference was observed among players in the field. Conclusions: Overall, we can conclude that, in a north African sample of female soccer players, anthropometric profiles vary by playing position. As well, positional differences can be found when testing physical fitness components. This information could help coaches design more effective training programs to achieve success in modern soccer.

Anthropometric and fitness associations in U17 Italian football players.

The purpose of this study was to determine possible relationships between anthropometric characteristics and functional capacities in young football (soccer) players. Anthropometric characteristics, estimated peak height velocity (PHV), muscular endurance (sit-up), lower-limb power (countermovement jump, CMJ), sprint time over 5 and 15 m (T5 and T15), agility (Arrowhead agility test), repeated sprint ability (RSA), intermittent recovery capacity (Yo-Yo intermittent recovery test, Yo-Yo IR1) and technical skills (short dribbling tests) were assessed in a group of U17 players (N.=47) competing at regional level. Magnitude-based inferences were used for analyses. Players with later PHV had greater muscle endurance (r [90% CIs] =0.41 [0.18; 0.59]) and CMJ (r=0.47 [0.25; 0.64]). Body mass, height and percentage of fat mass were positively associated to T5 and T15 (r=0.24-0.47). CMJ was moderately associated with agility, T5, T15 and Yo-Yo IR1 performance (r=-0.42 [-0.60; -0.19], -0.57 [-0.71; -0.38], 0.35[0.11; 0.54], respectively). Quickest players over 15 m were also the most agile and the most capable to perform intermittent recovery exercise (r=0.30-0.36). No significant correlations were found for RSA and other variables. Body size is likely detrimental for power-related capacities (tallest and heaviest players reported the lowest sprint performance). Notwithstanding, sprint and jump were related to greater intermittent recovery performance. However, caution should be taken when generalizing our findings, given our reduced sample size. In addition, our observed correlations were of small-to-moderate magnitude, and therefore, future research should explore further determinants of functional capacities in these age-group players.

The Use of Small-Sided Games as an Aerobic Fitness Assessment Supplement Within Elite Level Professional Soccer.

The purpose of this investigation was to quantify the association between 5 vs. 5 small sided games (SSG) running performance and physiological performance during the Yo-YoIR1 test to ascertain the utility of SSGs as a potential fitness test modality within elite professional soccer players. Twenty-three (n = 23) elite male professional soccer players (mean ± SD age 25.3 ± 3.1 yrs, mass: 76 ± 9 kg, height: 176 ± 9 cm) were assessed. Players completed an intermittent aerobic fitness test (Yo-YoIR1) and a 5 vs. 5 SSGs protocol for the purpose of the study. During all SSGs players wore GPS (Statsports 10-Hz, Viper Pod, Newry, Northern Ireland) and HR monitors (Polar, Oy Kemple, Finland) with these measures related to Yo-YoIR1 running performance. Results revealed SSGs running performance (TD; m) and physiological performance (HR) showed the lowest CV% (< 5%), with high speed movements, accelerations and decelerations highlighting higher CV% during SSGs. Possibly small to possibly very large associations were observed for running performance during 5 vs. 5 SSGs and Yo-YoIR1 performance, with negative associations observed between physiological performance during SSG and YoYoIR1 running performance. To conclude, the current study observed how running performance during a standardised 5 vs. 5 SSG protocol within elite soccer cohorts is associated with the Yo-YoIR1 running performance. Given the low CV%, repeatability and large association of global running performance and internal load measures during a 5 vs. 5 SSG with Yo-YoIR1 performance, this particular soccer specific SSG protocol potentially supplements traditional non-sport specific testing assessments.

Methods of Monitoring Training Load and Their Association With Changes Across Fitness Measures in Hurling Players.

Malone, S, Hughes, B, Collins, K, and Akubat, I. Methods of monitoring training load and their association with changes across fitness measures in hurling players. J Strength Cond Res 34(1): 225-234, 2020-The aim of the current investigation was to assess the dose-response relationship for various methods of monitoring training load (TL) and changes in aerobic and anaerobic fitness in hurling players. Training and match load measures were collected from 30 hurling players (speed at different blood lactate [vLT, vOBLA], maximal oxygen uptake [VO2max], speed at VO2max [vVO2max], peak treadmill velocity [PTV] running economy [RE] Yo-Yo intermittent recovery test (Yo-YoIR1, Yo-YoIR2), speed at 5, 10 , 20 m, and repeated sprint ability [6 × 35 m]) before and after during a 12-week in-season period. Mean weekly training and match loads as determined by s-RPE, bTRIMP, luTRIMP, eTRIMP, iTRIMP, and gTRIMP were correlated with each other, percentage change in VO2max, vVO2max, RE, PTV, the speed at blood lactate concentrations of 2 mmol·L (vLT) and 4 mmol·L (vOBLA), and YoYoIR1, Yo-YoIR2 performance. iTRIMP showed a trivial association with s-RPE and a small to moderate association with other heart rate-based methods. Small to large changes (effect size: 0.38-1.12) were observed in aerobic and anaerobic fitness measures were observed across the 12-week period. Trivial to very large associations (r = 0.11-0.78) were observed between TL variables and changes in fitness depending on the variable analyzed. iTRIMP was shown to have large to very large associations with changes in vOBLA {r = 0.78 (95% confidence interval [CI]: 0.71-0.88)}, VO2max (r = 0.77 [95% CI: 0.68-0.82]), RE (r = 0.77 [95% CI: 0.67-0.82]), Yo-YoIR1 (r = 0.69 [95% CI: 0.51-0.72]), and RSAb (r = 0.66 [95% CI: 0.60-0.72]) with moderate associations reported between iTRIMP and other variables. All other measures of TL showed trivial to moderate associations (r = 0.11-0.66). The current investigation shows that fully individualized training load (iTRIMP) measures may potentially offer a better understanding of dose-response relationships when compared with subjective and nonindividualized measures of TL to changes in aerobic and anaerobic fitness in team sports athletes; as such, it may be suggested that practitioners should use individualized measures of TL assessment within their day-to-day practices.

Acute effect of different stretching protocols on flexibility, yoyo IR-1 and repeated sprint ability performance

The purpose of this study was to examine the acute effect of different stretching protocols on flexibility, Yo-Yo IR-1 and repeated sprint performance. The sample group of this study consists of 15 male (age: 21.80±1.37 years, stature: 1.77±.032 cm, body mass: 69.09±6.65 kg, body mass index (BMI) 21.94±2.01 (kg/m 2 ), body fat ratio (BFR) 10.87±3.98 (%)) who were doing regular exercise at least 3 years. This group performed 5 different stretching protocols on non-consecutive days. Stretching protocols were determined as follows: light jogging for only 5 minutes (NS), light jogging and static strectching (SS), light jogging and dynamic stretching (DS), light jogging and static + dynamic stretching (SDS), light jogging and dynamic + static stretching (DSS). Altough participants did not have a statistically significant effect on flexibility performance (p> 0.05), the best flexibility value was SS. Repeated sprint performance (best) values ​​of different stretching protocols did not have statistically significant effect on repeated sprint performance (moderate, worst, decline, post fatigue index) values (p> 0.05). Repeated sprint performance was found to have a statistically significant effect on Borg values ​​and HR mean values ​​(p <0.05). It was found that Yo-Yo IR-1 has a statistically significant effect on BORG values, Yo-Yo IR-1 performance HR (pre) values, Yo-Yo IR-1 performance HR (middle) values ​​and Yo-Yo IR-1 performance lactate values (p<0.05). According to the findings obtained as a result of the research; it has been observed that different stretching protocols have different effects in terms of repeated sprint, flexibility and Yo-Yo IR-1 performance parameters. Overall, these results suggest that flexibility performance may be improve after static stretching exercise.

Factors Affecting the Anthropometric and Physical Characteristics of Elite Academy Rugby League Players: A Multiclub Study.

To investigate the factors affecting the anthropometric and physical characteristics of elite academy rugby league players. One hundred ninety-seven elite academy rugby league players (age = 17.3 [1.0]y) from 5 Super League clubs completed measures of anthropometric and physical characteristics during a competitive season. The interaction between and influence of contextual factors on characteristics was assessed using linear mixed modeling. All physical characteristics improved during preseason and continued to improve until midseason, whereafter 10-m sprint (η2 = .20 cf .25), countermovement jump (CMJ) (η2 = .28 cf .30), and prone Yo-Yo Intermittent Recovery (Yo-Yo IR) test (η2 = .22 cf .54) performance declined. Second (η2 = .17) and third (η2 = .16) -year players were heavier than first-years, whereas third-years had slower 10-m sprint times (η2 = .22). Large positional variability was observed for body mass, 20-m sprint time, medicine-ball throw, CMJ, and prone Yo-Yo IR1. Compared with bottom-ranked teams, top-ranked teams demonstrated superior 20-m (η2 = -.22) and prone Yo-Yo IR1 (η2 = .26) performance, whereas middle-ranked teams reported higher CMJ height (η2 = .26) and prone Yo-Yo IR1 distance (η2 = .20) but slower 20-m sprint times (η2 = .20). These findings offer practitioners who design training programs for academy rugby league players insight into the relationships between anthropometric and physical characteristics and how they are influenced by playing year, league ranking, position, and season phase.

Coaches’ and Young soccer players' training load perceptions during different training phases

Objective: To our Knowledge, information about the agreement between coaches’ and the young soccer players’ session rating of perceived exertion is not consistent during specific periods of training (intensification and taper) and has not been established. The purpose of this study was to examine and compare the internal training load and session rating of perceived exertion between coaches’ and young soccer players’ during three weeks in different training phases.&#x0D; Method: Participants were 16 male elite Under19 soccer players and their coaches. Before each training session, the coaches reported a session rating of perceived exertion using the Borg CR-10 scale as well as the planned duration (min) of the training based on prior planning, while the athletes responded the scale after each training session.&#x0D; Results: No differences in intensity session rating of perceived exertion (t = 0.49; p = 0.62) and training load (t = 0.18; p = 0.86) were observed between coaches and players during the training period analyzed. During different training phases, no significant differences were found during intensification (t = 0.18; p = 0.85) and taper (t = -0.19; p = 0.85) in training loads and in the session rating of perceived exertion prescribed by coaches and perceived by players. A very large correlation was observed between coaches training load (r= 0.84) and players training load. However, a trivial correlation was found between players training load and changes in the Yo-yo IR1 performance (r= -0.09), age (r= -0.06) and years of competitive experience (r= -0.08). Stepwise linear regression revealed that coaches training load (F1; 238= 582.7; R2= 0.710; p&lt;0.001) explained 71% of the variance in players training load.&#x0D; Conclusion: The results suggest that the session rating of perceived exertion and training load prescribed during three weeks in different training phases (by coaches) was not different from perceived by young soccer players. Moreover, coaches training load seem to be effective to predict the training load in soccer players.

Relationship Between Resting Heart Rate Variability and Intermittent Endurance Performance in Novice Soccer Players

ABSTRACTPurpose: This study examined the relationships between the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) and resting heart rate variability (HRV) and submaximal 5ʹ-5ʹ test derived measures in novice male soccer players. Methods: Forty players (11.54 ± 0.58 years) from a soccer academy participated in this study, performing physical tests on two different days, separated by 48 h, as follows: (day 1) resting HRV and Yo-Yo IR1 test, and (day 2) anthropometric assessments (for peak height velocity assessment [PHV]) and the 5ʹ-5ʹ test. The Pearson product-moment correlation coefficient was used to determine the correlations between Yo-Yo IR1 performance and the remaining variables. A partial correlation analysis was further performed using age, stature, body mass, distance to PHV, and age at PHV as “confounders.” Results: The highest correlation score was observed between Yo-Yo IR1 performance and resting HRV, when the absolute age was used as confounder (r = 0.72; p < .05). Conclusions: We observed that a practical measure of parasympathetic activity at rest is largely associated with performance obtained during a traditional intermittent endurance performance test.

Effect of Training Load Distribution on Aerobic Fitness Measures in Hurling Players

Malone, S, Hughes, B, and Collins, K. Effect of training load distribution on aerobic fitness measures in hurling players. J Strength Cond Res 33(3): 825-830, 2019-The aim of the current investigation was to quantify the training intensity distribution of hurling players and their association with changes in aerobic fitness measures within hurling players. Thirty hurling players (n = 30; age 26.5 ± 3.2 years; height 178.9 ± 3.2 cm; body mass 81.5 ± 4.5 kg) were observed during the pre-championship training period (12 weeks). Aerobic fitness measures (V[Combining Dot Above]O2max), peak treadmill velocity (km·h), heart rates (HRs) at 2 and 4 mmol·L blood lactate concentrations, and Yo-Yo intermittent recovery test performance (Yo-YoIR1) were assessed before and after the training period. Training intensities were categorized using 3 individualized HR zones based on the following criteria: low intensity (≤HR 2 mmol·L), moderate intensity (between HR 2 and 4 mmol·L), and high intensity (≥HR 4 mmol·L). Analysis of 1,025 individual training sessions showed that players spent 58.1 ± 2.5%, 24.3 ± 2.9%, and 17.6 ± 1.3% of time in the low-, moderate-, and high-intensity zones, respectively. The training time spent at high intensity (Zone 3) showed moderate-to-large associations with improvements in S2 (r = 0.80; p = 0.04) and S4 (r = 0.58; p = 0.03). Similar trends were observed for time spent in high intensity and improvements in V[Combining Dot Above]O2max (r = 0.77; p = 0.001) and Yo-YoIR1 performance (r = 0.65; p = 0.05). Hurling players have been shown to spend the majority of training time in low (≤ HR 2 mmol·L) to moderate intensity (between HR 2 and 4 mmol·L) training. However, only the time spent at high intensity (≥90% of maximal HR) was related to changes in aerobic fitness. These results support the usefulness of the quantification of aerobic training load using HR. The study also supports the efficacy of spending elements of training time within the high-intensity zone to increase hurling player's aerobic fitness characteristics.

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.