Yo-Yo Intermittent Endurance Test Level Research Articles

Effect of 3min whole-body and lower limb cold water immersion on subsequent performance of agility, sprint, and intermittent endurance exercise.

The aim of this study was to investigate the effects of whole-body cold-water immersion (WCWI) and lower-limb cold-water immersion (LCWI) employed during a 15-min recovery period on the subsequent exercise performance as well as to determine the physiological and perceptual parameters in the heat (39°C). Eleven males performed team-sports-specific tests outdoors. The exercise program consisted of two identical exercise protocols (1 and 2) separated by a 15-min recovery period. The participants completed the same tests in each exercise protocol, in the following order: agility t test (t-test), 20-m sprint test (20M-ST), and Yo-Yo Intermittent Endurance Test Level 1 (Yo-Yo). During the recovery period, a 3-min recovery intervention of a passively seated rest (control, CON), WCWI, or LCWI was performed. The t-test and 20M-ST for the CON group were significantly longer during exercise protocol 2, but they were not significantly different between the two exercise protocols for the WCWI and LCWI groups. The completed Yo-Yo distance for the CON and LCWI groups was shorter during exercise protocol 2, but it was not significantly different between the two exercise protocols for the WCWI group. The chest temperature (Tchest), upper arm temperature (Tarm), thigh temperature (Tthigh), mean skin temperature (Tskin), and thermal sensation (TS) values were lower for the WCWI group than for the CON group; but only the Tthigh, Tskin, and TS values were lower for the LCWI group compared to the CON group. The Tchest, Tarm, Tskin, and TS values after the intervention were lower for the WCWI group than for the LCWI group. None of the three intervention conditions affected the core temperature (Tcore), heart rate (HR), or rating of perceived exertion (RPE). These results suggest that WCWI at 15°C for 3 min during the 15-min recovery period attenuates the impairment of agility, sprint, and intermittent-endurance performance during exercise protocol 2, but LCWI only ameliorates the reduction of agility and sprint performance. Furthermore, the ergogenic effects of WCWI and LCWI in the heat are due, at least in part, to a decrease of the Tskin and improvement of perceived strain.

Types of Physical Activity and Sports for teens in Maintaining Physical Fitness in Leisure

This study aims to determine the types of physical activities and sports carried out by adolescents in maintaining their physical fitness outside of physical education learning at school. Especially to test the physical activity carried out without using the tool for one month with the number of meetings 10 times. The application of physical activity and exercise is carried out 2 or 3 times per week with a duration of 30 minutes. The research method used is experimental. Participants who took part in this study were 66 students consisting of 45 male students and 16 female students. Physical fitness measurements were carried out using the Yo-Yo Intermittent Endurance Test Level 2. Deeper sports participation, this study divided into outdoor sports and not using tools, both of which were associated with physical activity. The results of this study indicate that the analysis of the mean difference test in the control group obtained t 0 of 10.392 and t table of 2.035 with degrees of freedom (db) 32 and = 0.05. The hypothesis is that there are differences in the average physical fitness of students who are not given physical activity and sports treatment. While the results of statistical analysis of the experimental group obtained t 0 of 21.582 and t table 2.035 with degrees of freedom (db) 32 and = 0.05. The hypothesis is that there are differences in physical fitness in students who are given physical activity and sports treatment. the conclusion is that physical activity and sports support the improvement of physical fitness in adolescent students who are physically active at least once every 2-3 weeks. However, the shortcoming of this study was that it did not see what physical activities and sports the participants did outside of the treatment given.

Players with high physical fitness are at greater risk of injury in youth football.

The aim of this study was to investigate physical fitness, football-specific skills, and their association with injury risk in youth football. Altogether 447 male and female players aged 9-14 years (median 12 years) participated in performance tests and prospective follow-up. The physical fitness tests included five-jump test for distance, 30-m sprint, football-specific figure of eight agility, countermovement jump, and Yo-Yo intermittent endurance test level 1. The football-specific skill tests included dribbling and passing tests. Injuries and exposure were registered during the 20-week follow-up. Our candidate risk factors were low/high level of physical fitness measured with a composite score of physical fitness tests and low/high level of football-specific skills measured with a composite score of dribbling and passing tests. Secondarily, we investigated performance in individual tests and their association with injury risk. During the follow-up, players reported 565 injuries (264 acute and 301 overuse injuries). High level of physical fitness was associated with increased rate of all injuries (age-, sex-, and mean team exposure-adjusted IRR: 1.28, 95% CI: 1.04-1.58). The level of football-specific skills had no influence on the overall injury rate. Burden of overuse injuries, but not acute injuries was significantly higher in most fit players compared with the players in the reference group (IRR: 2.09, 95% CI: 1.04-4.24). In conclusion, most fit players were at greater risk of sustaining injuries in youth competitive football.

Relationship Between Yo-Yo Intermittent Endurance Test-Level 1 and Match Running Performance in Soccer: Still on the Right Path?

Abstract Introduction. The Yo-Yo Intermittent Endurance Test-Level 1 (Yo-Yo IR1) is considered a valuable measurement tool in assessing specific soccer endurance. However, there is a lack of recent research validating this test with regard to match running performance (MRP) in elite-level soccer. Material and Methods. The aim of this study was to evaluate the validity of Yo-Yo IR1 in predicting MRP during elite-level soccer matches. The participants were soccer players who competed in the highest-level Croatian soccer league (23.57 ± 2.84 years, 181.9 ± 5.17 cm, 78.36 ± 4.18 kg), and they were all tested using Yo-Yo IR1 in the middle of the season 2019/2020. The players’ MRP (n = 71) was measured using the Global Positioning System over one-half season, and included the total distance covered, the distance covered in different speed zones, accelerations and decelerations. The association between MRP and Yo-Yo IR1 was identified with Pearson’s correlation. Results. The results indicated that central midfielders and fullbacks achieved significantly higher results in Yo-Yo IR1 than forwards and central defenders (F-test: 29.80; p < 0.01; large effect size). Higher results in Yo-Yo IR1 were correlated with the match amount of (i) the total distance covered (r = 0.65); (ii) high-speed running (r = 0.42); (iii) high-intensity distance covered (r = 0.36); (iv) total accelerations (r = 0.37); and total decelerations (r = 0.42). Conclusions. The established associations between Yo-Yo IR1 and MRP in this study confirmed the validity of Yo-Yo IR1 in predicting MRP in professional soccer today.

Associations of Body Composition, Maximum Strength, Power Characteristics with Sprinting, Jumping, and Intermittent Endurance Performance in Male Intercollegiate Soccer Players.

The purpose of this study was to determine the relationships between body composition, strength, power characteristics, sprinting, jumping, and intermittent endurance performance in collegiate male players. Twenty-three players participated (19.7 ± 1.6 yrs; 71.8 ± 7.1 kg; 176.5 ± 5.1 cm). Measurements of interest in body composition included body fat percentage (BF%), lean body mass (LBM), and body mass (BM). Power characteristics were measured with an unloaded squat jump (SJ0) and loaded SJ at 20 kg (SJ20) and 40 kg (SJ40), and unloaded countermovement jump (CMJ0). Power assessments included peak power (PP) and PP allometrically scaled (PPa). Strength characteristics were assessed using isometric mid-thigh pull. Strength assessment included isometric peak force (IPF) and IPF allometrically scaled (IPFa). Performance measures included 10m and 20 m sprint time, CMJ0 jump-height, and Yo-Yo intermittent endurance test level 1 distance. Significant correlations ranging from moderate to very large were found for LBM and CMJ jump height (CM0 JH) (p = 0.01, r = 0.50); BF% and sprint times at 10 m (p = 0.03, r = 0.44) and 20 m (p = 0.02, r = 0.50). PP and PPa from SJ0 and CMJ0 were significantly correlated to 10m sprint time (p < 0.05, r = −0.45 to −0.53) and 20 m sprint time (p < 0.05, r = −0.40 to −0.49). Our findings agree with previous literature in that body composition and power characteristics are directly related to soccer-related performance.

RELATIONSHIP BETWEEN MORPHOLOGICAL CHARACTERISTICS AND PHYSICAL ABILITIES IN VOLLEYBALL PLAYERS

This research aims to determine the relationship between morphological characteristics and abilities in volleyball players. It was conducted on the territory of Vojvodina autonomous province on a sample of 27 male volleyball players with an average age of 17.48 ± 0.50 years and an average sports experience of 6.33 ± 2.83 years. A test battery consisting of five variables for measuring morphological characteristics and twelve tests of abilities was applied: flexibility, speed, agility, endurance, static and explosive power. The normality of the data distribution was controlled by the Shapiro-Wilk test, and the connection between morphological characteristics and abilities was calculated by the Spearman ro correlation coefficient. The limit value for testing the normality of distribution of p&gt; 0.05 was not met by: body mass index (p = 0.01), straddle in supine position (p = 0.03), single leg counter movement jump with the left leg (p = 0.01) and Yo-Yo Intermittent endurance test level 2 (p = 0.02). The connection of morphological characteristics with explosive power tests is especially noticeable, the most significant is the range of arms span with continuous jump with bent legs (ro = 0.75), single leg counter movement jump with the right leg (ro = 0.74) and Counter movement jump (ro = 0.63). The main finding in this study is that morphological characteristics are mostly negatively correlated with the explosive power of volleyball players. It is known that these characteristics and abilities have a significant share in the model of the ideal volleyball player and therefore their negative connections, the approach to the selection of volleyball and volleyball training must be based on scientific knowledge. Key words: measurement, testing, diagnostics, test batteries, volleyball

Reliability and Validity of a 6-Minute Yo-Yo Intermittent Endurance Test Level 2 in Subelite Part Time Male Soccer Players.

Gibson, N, Easton, C, Williams, M, McCunn, R, Gibson, NV. Reliability and validity of a 6-minute Yo-Yo Intermittent Endurance Test Level 2 in subelite part time male soccer players. J Strength Cond Res 36(4): 1011-1018, 2022-The aim of this study was to assess the reliability and relationship to maximal intermittent running performance of the 6-minute Yo-Yo Intermittent Endurance Test Level 2 (YYIET2), among subelite part time soccer players. Twenty male soccer players (15-22 years) completed three 6-minute YYIET2 trials with heart rate (HR), PlayerLoad, and rating of perceived exertion assessed during the protocol and HR and blood lactate assessed during 5 minutes of recovery. Subjects also completed a maximal version of the YYIET2 and the maximal Yo-Yo Intermittent Recovery Test Level 1 (YYIRT1) and 2 (YYIRT2). Heart rate at 4 and 6 minutes, PlayerLoad at 4 minutes, and HR recovery at 2, 3, 4, and 5 minutes during recovery from the 6-minute YYIET2 demonstrated little variance between tests. Correlations between variables measured during and after the 6-minute YYIET2 and distance covered in maximal tests ranged from r = 0.02 to -0.72. The 6-minute YYIET2 provides practitioners with a method of reliably assessing HR responses within subelite part time soccer players, although large correlations with maximal assessments suggest it can be used as a proxy measure for maximal intermittent running performance. Given its ease of administration and low time cost, the 6-minute YYIET2 offers practitioners a useful means of tracking training status and movement efficiency in players longitudinally.

The Yo-Yo Intermittent Endurance Level 2 Test: Reliability of Performance Scores, Physiological Responses and Overload Characteristics in Competitive Soccer, Basketball and Volleyball Players.

The purpose of this study was to evaluate the reliability and reproducibility of the physiological and overload features of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2) in competitive male soccer (n = 20), basketball (n = 11), and volleyball players (n = 10). The participants completed Yo-Yo IE2 tests on three separate occasions with assessment of performance, heart rate, running speed, accelerations, decelerations and body load using GPS instrumentation. The intra-class correlation coefficient index, confidence intervals and coefficients of variation were calculated to assess the reliability of the test. Intra-class correlation coefficients for test-retest trials in the total sample ranged from large to nearly perfect (total distance: 0.896; mean speed: 0.535; maximum speed: 0.715; mean HR: 0.876; maximum HR: 0.866; body load: 0.865). The coefficients of variation for distance, mean speed, HR response, as well as acceleration and deceleration scores for test-retest trials ranged from 1.2 to 12.5% with no differences observed among particular sport disciplines. The CV for shuttles performed ranged from 4.4 to 5.5% in all sports. Similar results were obtained for the three different categories of players tested. These results suggest that the Yo-Yo IE2 test appears to be a reliable alternative for evaluating the ability to perform intermittent high-intensity running in different outdoor and indoor team sports. Players may need one or two familiarization tests to ensure valid assessment of intermittent endurance capacity. It appears that the Yo-Yo IE2 test incorporates accelerations and decelerations in a consistent and reproducible fashion.

Heart Rate Kinetics Response of Pre-Pubertal Children during the Yo-Yo Intermittent Endurance Test-Level 1.

This study analyzed heart rate (HR) kinetics during the Yo-Yo Intermittent Endurance Test—level 1 (Yo-Yo IE1) in children. At the middle of the school year, 107 boys (7–10 years old) performed the Yo-Yo IE1. Individual HR curves during the Yo-Yo IE1 were analyzed to detect an inflection point between an initial phase of fast rise in HR, and a second phase in which the rise of HR is slower. The 7th shuttle of the test was established as the inflection point. Engagement with extra-school sports practice was identified. Percentile groups (P1, P2 and P3) were created for body weight and physical fitness data composite (PFcomposite). Differences were found between the slopes of P1 and P3 on phase 1 for body weight (12.5 ± 2.7 vs. 13.7 ± 2.0 bpm/shuttle; p = 0.033; d = 0.50) and PFcomposite (14.2 ± 2.5 vs. 12.5 ± 2.0 bpm/shuttle; p = 0.015; d = 0.75). Time spent >95% of peak HR was longer for the children engaged with extra-school sports practice (335 ± 158 vs. 234 ± 124 s; p < 0.001; d = 0.71); differences were also detected for PFcomposite (P1, P2 and P3: 172 ± 92, 270 ± 109, and 360 ± 157 s, respectively; p < 0.05; d = 0.66–1.46). This study indicates that physical fitness and body weight influence HR kinetics during the Yo-Yo IE1 in pre-pubertal boys.

Can compression stockings reduce the degree of soccer match-induced fatigue in females?

ABSTRACTSoccer-induced fatigue and performance are different between the sexes. The effect of compression stockings (CS) use on fatigue during the soccer match in females is unknown. Thus, we evaluated the impact of CS use during a female soccer match on match-induced fatigue. Twenty soccer players were randomly allocated to two groups (n = 10 for each group): CS and Control (regular socks), and equally distributed within two teams. At rest (baseline 48-h before the match) and immediately post-match, we assessed agility T-test, standing heel-rise test and YoYo Intermittent Endurance Test level 2 (YoYoIE2) performance. Effort during the match (heart rate and rating of perceived exertion) was similar (p > 0.05) between groups. The YoYoIE2 performance was decreased post-match (p < 0.05) equally for both groups. Otherwise, the CS group exhibited a greater post-match performance (p < 0.05) for the agility T-test and heel-rise test (large effect sizes). Therefore, we conclude that the use of CS during an amateur female soccer match resulted in less match-induced fatigue.

The Acute Effect of Yo-Yo Intermittent Endurance Test Level 1, on Vertical Jump Height of Volleyball Players

The Acute Effect of Yo-Yo Intermittent Endurance Test Level 1, on Vertical Jump Height of Volleyball Players

Acute ischemic preconditioning does not influence high-intensity intermittent exercise performance.

This study evaluated the acute effect of ischemic preconditioning (IPC) on a high-intensity intermittent exercise performance and physiological indicators in amateur soccer players. Thirteen players (21.5 ± 2 yrs) attended three trials separated by 3–5 days in a counterbalanced randomized cross-over design: IPC (4 × 5-min occlusion 220 mmHg/reperfusion 0 mmHg) in each thigh; SHAM (similar to the IPC protocol but “occlusion” at 20 mmHg) and control (seated during the same time of IPC). After 6-min of each trial (IPC, SHAM or control), the players performed the YoYo Intermittent Endurance Test level 2 (YoYoIE2). The distance covered in the YoYoIE2 (IPC 867 ± 205 m; SHAM 873 ± 212 m; control 921 ± 206 m) was not different among trials (p = 0.10), furthermore, lactate concentration and rate of perceived exertion did not differ (P > 0.05) among protocols. There were also no significant differences in either mean heart rate (HR) or peak HR (p > 0.05) for both IPC and SHAM compared to control. Therefore, we conclude that acute IPC does not influence high-intensity intermittent exercise performance in amateur soccer players and that rate of perceived exertion, heart rate and lactate do not differ between the intervention IPC, SHAM and control.

Fitness and health benefits of team handball training for young untrained women—A cross-disciplinary RCT on physiological adaptations and motivational aspects

PurposeThe present study evaluated the effects of regular participation in small-sided team handball training on body composition, osteogenic response, physical performance, and cardiovascular risk factors, as well as well-being and motivation, in young untrained women. MethodsTwenty-eight untrained 20- to 30-year-old women were randomized to a handball training group (HG; n = 14, height 170 ± 5 cm, weight 73 ± 11 kg, VO2peak 37.7 ± 4.1 mL/min/kg) that trained 1.7 ± 0.3 times per week over 12 weeks (70 min 4 v 4 handball sessions) or an inactive control group (CG; n = 14, 169 ± 5 cm, 71 ± 12 kg, 38.1 ± 3.7 mL/min/kg). Physiological and psychological and motivational training adaptations were assessed pre- and post-intervention by dual-energy X-ray Absorptiometry (DXA) scans, blood sampling, physical tests, and questionnaires. ResultsThe average heart rate (HR) over all training sessions was equal to 85% ± 6% HRmax. Between-group intervention effects were observed in favor of HG for muscle mass (2.1%, p = 0.024), proximal femur bone mineral density (0.8%, p = 0.041), Yo-Yo IE1 intermittent endurance test level 1 (IE1) performance (35%, p < 0.001), and incremental treadmill test performance (11.5%, p = 0.003), but not total fat mass (p = 0.176), mean arterial blood pressure (p = 0.328), resting HR (p = 0.219), or blood lipids (p = 0.298–0.854). In CG, no changes were observed in any of the measured physiological variables after the training period. Compared to CG, HG had an increase in intrinsic motivation (p < 0.001) and in the well-being subscale “energy” (p = 0.010). ConclusionParticipation in regular recreational team handball training organized as small-sided games has marked beneficial effects on physical performance, musculoskeletal fitness, well-being, and motivation in untrained young women.

Anthropometric, speed and endurance characteristics of English academy soccer players: Do they influence obtaining a professional contract at 18 years of age?

This study evaluated the anthropometric, speed and endurance characteristics of English academy soccer players, comparing players who obtained a ‘professional’ contract at 18 years old with those that did not (‘academy’); 443 male academy soccer players from an English professional club undertook anthropometric (height and body mass), speed (10 and 20 m sprint) and endurance (Yo-Yo intermittent endurance test level 2 [Yo-Yo]) assessments between 2005 and 2012. Significant improvements with age were found for speed and endurance at each annual age group up until U18 age category. Significant differences were only observed between ‘professional’ and ‘academy’ players for 10 m ( p = 0.003, η2 = 0.01) and 20 m ( p = 0.001, η2 = 0.01) speed at U16 and U18 and Yo-Yo performance ( p = 0.001, η2 = 0.12) at U18 age category. Practitioners should use speed and endurance assessments for monitoring physical development of players rather than for talent identification purposes.

Yo-Yo Intermittent Endurance Test-Level 1 to monitor changes in aerobic fitness in pre-pubertal boys

The present study aimed to examine the performance and heart rate responses during the Yo-Yo Intermittent Endurance Test-Level 1 (Yo-Yo IE1) in children under the age of 10. One hundred and seven male children (7–9 years) performed the Yo-Yo IE1 at the beginning (M1), middle (M2) and end (M3) of the school year. Data from individual heart rate curves of the Yo-Yo IE1 were analysed in order to detect the inflection point between an initial phase of fast rise in heart rate values and a second phase in which the rise of the heart rate values is much smaller. The distance covered in the Yo-Yo IE1 improved from M1 to M3 (884 ± 496 vs. 1032 ± 596 m; p < 0.05; d = 0.27), with intermediate values for M2 (962 ± 528 m). Peak heart rate (HRpeak) decreased from M1 to M2 and M3 (204 ± 9, 202 ± 9 and 200 ± 9 bpm, respectively; p < 0.05; d = 0.25–0.42). The 7th shuttle of the test (280 m), corresponding to 2.5 min, was identified as the inflection point between the two phases. Also, absolute heart rate at the 7th shuttle decreased progressively throughout the year (185 ± 9, 183 ± 10, and 179 ± 10 bpm; p < 0.05; d = 0.31–0.61). The present study provides evidence of the usefulness of a maximal as well as a submaximal version of Yo-Yo IE1 as a tool to monitor changes in aerobic fitness in pre-pubertal children.

The investigation of heart rate variation on endurance of professional soccer players

The main aim of the present study was to determine whether performance on the Yo-Yo intermittent endurance test can predict the real match performances, or not. The sample of players consists of elite professional soccer players (age 23.02±4.49 years, soccer experience 10.04±4.2 years, body mass 73.61±6,15 kg, height 1,79 ±0,52 m, body mass index 19,12 ±0,4 kg m , body fat 8,32 ±2,96 %) who were the members of the 2 Turkish Soccer Federation. For assessment of aerobic endurance performance used, the Yo-Yo intermittent endurance test level 1 was performed. Heart rate was recorded by a Polar Vantage NV heart rate monitor placed around the chest for continuous heart rate recordings throughout selected stages of the test. Descriptive statistics were calculated. Data are expressed as means and standard deviations for each variable. It is seen that the research group uses 83 % of MaxHR in average Heart Rate according to minimum, average and maximum HR values obtained according to max HR values of the research group. As a conclusion, it is understood that heart rate is an important factor obtained from the yo-yo test that the soccer players show similar efforts during the competition. So the heart rate values taken from this test used as intermittent test has the quality to estimate the players match performance.

Match performance and physical capacity of players in the top three competitive standards of English professional soccer

The aim of this study was to compare the match performance and physical capacity of players in the top three competitive standards of English soccer. Match performance data were collected from players in the FA Premier League (n=190), Championship (n=155) and League 1 (n=366) using a multiple-camera system. In addition, a selection of players from the Premier League (n=56), Championship (n=61) and League 1 (n=32) performed the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2) to determine physical capacity. Players in League 1 and the Championship performed more (p<.01) high-intensity running than those in the Premier League (Effect Size [ES]: 0.4–1.0). Technical indicators such as pass completion, frequency of forward and total passes, balls received and average touches per possession were 4–39% higher (p<.01) in the Premier League compared to lower standards (ES: 0.3–0.6). Players also covered more (p<.05) high-intensity running when moving down (n=20) from the Premier League to the Championship (ES: 0.4) but not when players moved up (n=18) standards (ES: 0.2). Similar Yo-Yo IE2 test performances were observed in Premier League, Championship and League 1 players (ES: 0.2–0.3). Large magnitude relationships (p<.05) were observed between Yo-Yo IE2 test performances and the total and high-intensity running distance covered in both Championship (r=.56 and .64) and Premier League matches (r=.61 and .54). The data demonstrate that high-intensity running distance was greater in players at lower compared to higher competitive standards despite a similar physical capacity in a subsample of players in each standard. These findings could be associated with technical characteristics inherent to lower standards that require players to tax their physical capacity to a greater extent but additional research is still required to confirm these findings.

O nível de condicionamento físico afeta a magnitude da carga interna de treinamento em jovens jogadores de basquetebol?

ObjectiveThe aim of this study was to investigate the influence of the ability to perform high intensity effort (HIE) on internal training load (CIT) responses in young basketball players. MethodTwelve male basketball players took part of the investigation (18.6 ± 0.5 years, 192 ± 6.5cm e 88.8 ± 14.5kg). The investigation lasted four weeks, with two weeks of a preparatory period (PP) and two weeks of a competitive period (PC). Session ratings of perceived exertion (session-RPE) method was used to quantify internal training load in every training session. Athletes performed the Yo-Yo Intermittent Endurance Test level 2 (Yo-Yo IE2) before and after the experimental period (4 weeks). For data analysis, Pearson correlation coefficient was used (Yo-Yo IE2 [PRE and POST] x CIT [General (PP and PC), PP and PC]) (p<0.05). ResultsNegative correlation coefficients, classified as “large” to “very large”, were observed between the performance in the Yo-Yo IE2 PRE and ITL in PP (r=–0.81), CP (r=–0.72), and in the whole experimental period (PP and CP) (r=–0.80) conditions. Correlation coefficients, classified as “large” to “very large”, were also observed between the performance in the Yo-Yo IR2 POST and ITL during PP (r=–0.83), CP (r=–0.66) and General (r=–0.78) conditions. ConclusionThe results of the present study suggest the existence of a strong correlation between the ability to perform HIE and ITL, thus indicating the importance of adopting an integrated monitoring of these variables, aiming to conduct regular adjustments on training load.

Responsiveness of the One-Leg Hop Test and the Square Hop Test to Fatiguing Intermittent Aerobic Work and Subsequent Recovery

The purpose of the present study was to evaluate the responsiveness of the 1-leg hop test and the square hop (SH) test to fatiguing intermittent aerobic work and during recovery. A further aim was to study sex differences in trends. Members of 4 sub-elite-level soccer teams were invited to participate. Ten men (mean ± SD) aged 20.7 ± 3.4 years and 10 women aged 21.8 ± 4.8 years accepted to participate in the test. The Yo-Yo intermittent Endurance test Level 2, was used as a standardized sport-specific fatiguing protocol. The 1-leg hop test and the SH test were performed before, immediately after, 15, and 30 minutes after the fatiguing exercise. To quantify the level and progression of fatigue and recovery, blood lactate and heart rate were measured, and general fatigue was estimated on Borg's rating of perceived exertion scale. No significant difference in performance in either of the hop tests was found immediately after intermittent aerobic fatiguing work. Performance in the 1-leg hop test significantly decreased (p = 0.002), whereas that in the SH test increased (p = 0.001) between baseline and 15-30 minutes after fatiguing work. No significant difference in trends between sexes was found. The performance in the 1-leg hop test significantly decreased during 30 minutes of recovery compared with that in the nonfatigued conditions and might therefore be used on the field as a complement to other physical parameters to detect remaining fatigue. Note that the 1-leg hop test did not immediately respond to intermittent aerobic work. It is not recommended to use the SH test for measuring fatigue and subsequent recovery because the performance constantly increased despite the present objective and subjective fatigue.

Training Status and Match Activity of Professional Soccer Players Throughout a Season

The purpose of this study was to examine match activity (MA) and fatigue development (FD) during official soccer games in different moments of a season and the influence of training status (TS) on MA and FD. Match activity of 13 professional players was examined by time-motion analysis at 4 time points of a competitive season. In addition, per time point within the 2-week period between the 2 games video-filmed, players performed the following physical tests: countermovement jump, 5- and 30-m sprints, change of direction, knee extensor and flexor isokinetic strength, and Yo-Yo intermittent endurance test-level 2. The players covered a greater high-intensity distance running (HI; p < 0.05) in the last quarter of the season (E4) than in the second (E2) and the third (E3) quarters. Within each assessment period, a greater distance was covered in HI during the peak 5-minute period of the match (P5-min) than in the 5-minute period after P5-min (Next5-min) and the remaining 5-minute periods (Av5-min; p < 0.05) of the match. Also, P5-min was higher in E4 than in the beginning of the season (E1, E2, and E3; p < 0.05). The physical fitness variables, composites scores of power-related and isokinetic strength tests were correlated (r ranging between 0.59 and 0.73, p < 0.05) with game physical parameters (GPPs) analyzed by time motion. Soccer players were found to cover more HI during the game and in the P5-min toward end of season. The players with greater muscle strength and power expressed lower performance decrements in the GPPs. In conclusion, the results highlight the relevance of players' neuromuscular function on game physical performance.