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\(\bf Purpose\) According to the official rules of the International Tennis Federation, players have to serve alternately from two different positions: the deuce (right, D) and the ad court (left, AD) side. This study aimed to compare body and ball kinematics of flat serves from both service sides. \(\bf Methods\) In a controlled, semi-court laboratory setting, 14 elite male junior players served eight flat first serves to a target field directed to the receiver’s body from both service positions in a matched and counterbalanced order. An 8-camera-Vicon-System was used to capture the 3D-landmark trajectories. \(\bf Results\) The mean service velocity was found to be similar on both sides (D: 151.4 \(\pm\) 19.8 vs. AD: 150.5 \(\pm\) 19.4 km/h), while multiple characteristics of the serve and ball kinematics differed significantly (p < .05). At starting, the front-foot angle relative to the baseline (D: 39.7\(\pm\)17.6° vs. AD: 31.1\(\pm\)17.4°) and lateral distance between the feet (D: 16.3 \(\pm\) 12.9 cm vs. AD: 26.2 \(\pm\) 11.9 cm) were significantly different. During the service, upper torso range of motion from maximum clockwise rotation until impact was significantly greater on the deuce court (D: 130.5 \(\pm\) 19.8° vs. AD: 126.7 \(\pm\) 21.1°). This was especially pronounced in foot-back technique players. Further, differences in the lateral ball impact location (D: 30.0 \(\pm\) 24.1 cm vs. AD: 10.3 \(\pm\) 23.3 cm) were observed. \(\bf Conclusions\) Changing the service side affects the serve and ball kinematics in elite junior tennis players. Our results underline biomechanical differences regarding the starting position (feet and upper torso) as well as the movement and ball kinematics which could be relevant for skill acquisition, injury prevention and performance enhancement.

The aim of this study was to investigate the effects of a mixed-method recovery intervention (MMR) consisting of active recovery, stretching, cold-water immersion, and massage on physical, technical, physiological, and perceptual recovery during and after a five-day simulated tennis tournament. Nine competitive male tennis players (age, 24.6±4.2 years) with national ranking positions (German Tennis Federation) and Universal Tennis Ratings between approximately 11 to 13 participated in two singles tennis tournaments, which were separated by a three-month washout period. During the tournaments, participants played five two-and-a-half-hour competitive singles tennis match on five consecutive days. For the assignment to one of two groups, athletes were matched into homogeneous pairs according to their ranking. Then, within each pair, the players were randomly assigned to one of two groups. The first group performed MMR during the first tournament, whereas the other group used passive recovery (PAS). During the second tournament, recovery conditions were interchanged. Measures of physical and technical performance as well as physiological and perceptual responses (heart rate, blood lactate concentration, perceived exertion) were recorded during match-play sessions. Furthermore, muscle soreness, perceived recovery state, blood markers, countermovement jump height (CMJ), and repeated sprint ability (RSA) were determined before, during, and after the five-day tournament periods. Results showed significant changes over time (P 0.05). In conclusion, the repeated use of MMR during and after a five-day tennis tournament did not affect match performance, match load, or recovery from repeated days of tennis match play.

Badminton, squash, table tennis, and tennis are four of the most popular racquet sports. In recent years, modifications in rules, equipment, and athletes’ physical fitness have led to changes in match structure and therefore also in demands on athletes of these sports. This has caused a sudden rise in requests for scientific research, since insight into a sport’s profile of requirements is crucial for efficient training monitoring. This review aims to offer a comprehensive overview about latest findings about activity profile and physiological responses in match play in the four racquet sports. Comparisons showed that the match structure of each of the four racquet sports is similar with regard to the intermittent character, but differences appear across all disciplines when comparing match, rally, and resting interval durations, work density, covered distances, and striking frequencies. Moreover, high average cardiorespiratory responses are reported for badminton and squash, but not for table tennis and tennis. In all racquet sports, continuous changes in high-intensity movement and periods of recovery are found, suggesting significant influence of both aerobic and anaerobic alactic energetic pathways. In contrast, lactic pathways seem to play an important role in squash, but less in the other racquet sports. These discrepancies in energetic demands are related to the differences in the total amounts of effort and recovery and their relationship to each other. To conclude, the four racquet sports have a lot in common, but each sport brings its own requirements. Badminton is highly dependent on reaction and anticipation, squash is high-intensity, table tennis is mostly skill-related, and tennis is less intensive, but of greatest volume of effort.

BACKGROUND: The aim of this crossover study was to investigate whether a cooling intervention during simulated tennis match play in the heat could affect players' performance, physiology, perception of effort, and well-being. METHODS: Eight competitive male tennis players performed two testing sessions of 45-minute simulated tennis match play on a hard court at 31.8±2.1°Cand 48.5±9.6% relative humidity. During change-of-end breaks, the cooling interventions (COL) consisted of cold-water ingestion (ad libitum) and an electric fan facing the players at a distance of 1 m combined with an ice-filled damp towel around the neck and on the thighs or no cooling (CON) were applied. Measures of performance, heart rate, blood lactate concentration, tympanic and local skin temperature, sweat loss, perceived exertion, and thermal sensation as well as ratings of recovery were recorded in both sessions. RESULTS: Paired-samples t-tests showed no significant differences (P>0.05) in any of the measures between COL and CON. Effect size (ES) calculations indicated moderate evidence that COL was beneficial to local skin temperature (ES=-0.95) and thermal sensation (ES=-0.77). At the individual level, a positive response to COLwas found in some players for heart rate, local skin temperature, thermal sensation, and ratings of recovery. CONCLUSIONS: Alikely inability of COLto improve players' performance or reduce thermal strain during tennis match play in hot humid conditions was found at the group level. However, some players may be more likely to benefit from COL. Therefore, the use of COL should be individualized.

Purpose: To identify whether the use of active recovery (ACT) the day after high-intensity interval training (HIIT) benefits recovery and to assess whether individual responses to ACT are repeatable. Methods: Eleven well-trained, male intermittent-sport athletes (age: 25.5 ± 1.8 y) completed 4 HIIT sessions, each separated by a 2-week washout period. Of the 4 sessions, 2 were followed by passive recovery (PAS) and 2 by 60 minutes of moderate biking (ACT) 24 hours postexercise in the following sequences: ACT→PAS→ACT→PAS or PAS→ACT→PAS→ACT. Before and after HIIT and after 24 and 48 hours of recovery, maximal voluntary isometric strength (MVIC), countermovement jump height (CMJ), tensiomyographic markers of muscle fatigue (TMG), serum concentration of creatine kinase (CK), muscle soreness (MS), and perceived stress state (PS) were determined. Results: A 3-way repeated-measure analysis of variance with a triple-nested random effects model revealed a significant (P P > .05) main effect of recovery strategy was detected. In 9 subjects, the individual results revealed inconsistent and nonrepeatable responses to ACT, while a consistent and repeatable positive or negative response to ACT was found in 2 individuals. Conclusions: The repeated failure of ACT to limit the severity of fatigue was found both at the group level and with most individuals. However, a small percentage of athletes may be more likely to benefit repeatedly from either ACT or PAS. Therefore, the use of ACT should be individualized.

Postexercise recovery is a fundamental component for continuous performance enhancement. Due to physiological and morphological changes in aging and alterations in performance capacity, athletes of different ages may recover at different rates from physical exercise. Differences in body composition, physiological function, and exercise performance between men and women may also have a direct influence on restoration processes. Purpose: This brief review examines current research to indicate possible differences in recovery processes between male and female athletes of different age groups. The paper focuses on postexercise recovery following sprint and endurance tests and tries to identify determinants that modulate possible differences in recovery between male and female subjects of different age groups. Results: The literature analysis indicates age- and sex-dependent differences in short- and long-term recovery. Short-term recovery differs among children, adults, and masters. Children have shorter lactate half-life and a faster cardiac and respiratory recovery compared to adults. Additionally, children and masters require shorter recovery periods during interval bouts than trained adults. Trained women show a slower cardiac and respiratory recovery compared to trained men. Long-term recovery is strongly determined by the extent of muscle damage. Trained adults tend to have more extensive muscle damage compared to masters and children. Conclusion: The influence of age and sex on the recovery process varies among the different functional systems and depends on the time of the recovery processes. Irrespective of age and sex, the performance capacity of the individual determines the recovery process after high-intensity and endurance exercise.

Our study aimed to examine athletics, training characteristics, and prevalence of musculoskeletal symptoms of male junior tennis Davis Cup players (DC) in comparison with their regional counterparts, as well as to evaluate the impact of age and performance level on training characteristics. Twelve junior DC (male) and two samples of regional squad players (RS1 n = 60 males, n = 47 females; RS2 n = 59 males) participated in a physical testing, an interview for data evaluation on training characteristics, and a questionnaire survey of orthopedic injury frequency. Results indicate higher physical performance levels (effect size (ES) 0.75–1.26) and training volumes in DC (ES 1.23–1.66). In DC, significant relationships were found between total training volume and tennis ranking ( r = −0.78), age and physical training volume ( r = 0.82), and age and total training volume ( r = 0.62). Injury frequencies showed moderate to high prevalence with no differences ( p > 0.05) between DC and RS. Given the demands of elite tennis and the important role of service in the modern game, more efforts are necessary to develop training prescription for both performance enhancement and prevention strategies.

Ermudung und Regeneration sind integrale Bestandteile des Trainingsprozesses. Dabei steht die kontinuierliche Leistungsentwicklung in standiger Wechselwirkung mit den durch Trainings- und Wettkampfaktivitaten ausgelosten Ermudungs- und Regenerationsvorgangen. Wahrend die Steigerung der Trainingsqualitat seit jeher im Fokus trainingswissenschaftlicher Bemuhungen steht, richtet sich das Augenmerk zunehmend auch auf die Erholungsprozesse und deren Optimierung. Das Regenerationsmanagement lasst sich dabei im Wesentlichen in die Messung des Regenerationsbedarfs sowie in die individualisierte Planung und Anwendung von Regenerationsstrategien strukturieren. Hierbei ist die Bedeutung einer angemessenen Ernahrung sowie von ausreichend Schlaf unbestritten. Zusatzlich kann in der (leistungs-)sportlichen Praxis aus einer Vielzahl an regenerationsfordernden Masnahmen ausgewahlt werden, deren Wirksamkeitsnachweis jedoch nur selten unter wissenschaftlich kontrollierten Bedingungen uberzeugend erfolgt ist. Dies gilt sowohl fur „traditionelle“ und bei den Athleten beliebte Masnahmen wie beispielsweise die Massage als auch fur neuartige Regenerationstrends wie Foam-Rolling oder fur technologisch unterstutzte Interventionsstrategien wie z. B. LED-Bestrahlung oder Kaltekammern. Sowohl Ermudungs- als auch Erholungsprozesse sind auserst komplexe und multifaktorielle Phanomene, die in Abhangigkeit von den Belastungsmerkmalen sowie adressaten- und umweltspezifischen Besonderheiten auf verschiedenen Funktionsebenen des menschlichen Organismus (u. a. Muskulatur, Bindegewebe, zentrales Nervensystem, autonomes Nervensystem, endokrines System) in unterschiedlichen zeitlichen Dimensionen sowie in unterschiedlicher Geschwindigkeit und Auspragung stattfinden. Basierend hierauf werden in diesem Kapitel sowohl die Wirkmechanismen und Effekte von Regenerationsinterventionen, die sich in der Sportpraxis groser Beliebtheit erfreuen, diskutiert als auch Grundlagen zum Ernahrungsmanagement im Sport besprochen. Unter Berucksichtigung individueller und sportartspezifischer Rahmenbedingungen werden Praxistipps fur die Regenerationssteuerung im (Leistungs-)Sport vorgestellt.

The aim of this paper was a) to analyse the intraindividual change and criterion sensitivity of the Acute Recovery and Stress Scale (ARSS) and its abridged version the Short Recovery and Stress Scale (SRSS) in response to a 6-day microcycle of intensified strength training (STM) and high-intensity interval training (HIIT) in comparison with the change in the criterion measures maximal dynamic strength (estimated 1 repetition maximum [1RMest]; STM) or repeated sprint ability (RSA; HIIT), and b) to compare descriptively the results of the subjective measures with earlier reported physiological and performance markers of the same study. Participants were 23 (STM; 23.7 ± 2.0 years) and 22 (HIIT; 22.8 ± 2.6) well-trained athletes who completed 11 training sessions over 6 days to induce functional overload. The ARSS scales and the SRSS items were assessed every morning and the criterion measures 3 times (pre, post1, post2). Changes were analysed over the entire period and from pre- to post training as well as after 72-h of recovery. ARSS and SRSS ratings and the criterion measures presented deteriorations upon the intensive training as well as improvements following the recovery period. The overall and physical-related scales/items demonstrated large change effects in response to the physical stress stimulus in both training protocols (Cohen’s d between |0.92| and |2.04|). The mental-related scales/items described moderate to large change effects (d = |0.30| to |0.73|) and the emotional-related scales/items small to moderate change effects (d = |0.07| to |0.51|). The sensitivity analyses revealed the highest diagnostic effectiveness also in the overall (45.50% to 73.90%) and physical-related (45.50% to 69.90%) scales/items, but they did not discriminate exactly athletes in fatigued or recovered state compared to the performance criterion measures. Correlation analyses also revealed no significant relationships between the changes in the scales/items and in the criterion measures. On a descriptive basis, comparisons with the change effect sizes and the sensitivity results of the performance and physiological markers underline the importance of psychological markers for the assessment of recovery and stress. Furthermore, the gained experiences in application and evaluation promote the practicability and economy of the questionnaires favouring the combination of subjective and objective markers for training monitoring in sports. The application and interpretation should mainly focus on the individual and longitudinal level.

The study investigates whether tensiomyography (TMG) is sensitive to differentiate between strength and endurance athletes, and to monitor fatigue after either one week of intensive strength (ST) or endurance (END) training. Fourteen strength (24.1±2.0years) and eleven endurance athletes (25.5±4.8years) performed an intensive training period of 6days of ST or END, respectively. ST and END groups completed specific performance tests as well as TMG measurements of maximal radial deformation of the muscle belly (Dm), deformation time between 10% and 90% Dm (Tc), rate of deformation development until 10% Dm (V10) and 90% Dm (V90) before (baseline), after training period (post1), and after 72h of recovery (post2). Specific performance of both groups decreased from baseline to post1 (P0.05) and returned to baseline values at post2 (P0.05). The ST group showed higher countermovement jump (P0.05) and shorter Tc (P0.05) at baseline. After training, Dm, V10, and V90 were reduced in the ST (P0.05) while TMG changes were less pronounced in the END. TMG could be a useful tool to differentiate between strength and endurance athletes, and to monitor fatigue and recovery especially in strength training.

This aimed to analyze neuromuscular, physiological and perceptual responses to a single bout of 5 different dynamic squat exercise protocols. In a randomized and counterbalanced order, 15 male resistance-trained athletes (mean ± SD; age: 23.1 ± 1.9 years, body mass: 77.4 ± 8.0 kg) completed traditional multiple sets (MS: 4 × 6, 85% 1 repetition maximum [RM]), drop sets (DS: 1 × 6, 85% 1RM + 3 drop sets), eccentric overload (EO: 4 × 6, 70% 1RM concentric, 100% 1RM eccentric), flywheel YoYo squat (FW: 4 × 6, all-out), and a plyometric jump protocol (PJ: 4 × 15, all-out). Blood lactate (La), ratings of perceived exertion (RPE), counter movement jump height (CMJ), multiple rebound jump (MRJ) performance, maximal voluntary isometric contraction force, serum creatine kinase (CK) and delayed onset muscle soreness were measured. Immediately post exercise, La was significantly (p < 0.001) higher in FW (mean ± 95% confidence limit; 12.2 ± 0.9 mmol·L) and lower in PJ (3.0 ± 0.8 mmol·L) compared with MS (7.7 ± 1.5 mmol·L), DS (8.5 ± 0.6 mmol·L), and EO (8.2 ± 1.6 mmol·L), accompanied by similar RPE responses. Neuromuscular performance (CMJ, MRJ) significantly remained decreased (p < 0.001) from 0.5 to 48 hours post exercise in all protocols. There was a significant time × protocol interaction (p ≤ 0.05) in MRJ with a significant lower performance in DS, EO, and FW compared with PJ (0.5 hours post exercise), and in EO compared with all other protocols (24 hours post exercise). A significant main time effect with peak values 24 hours post exercise was observed in CK serum concentrations (p < 0.001), but there was no time × protocol interaction. In conclusion, (a) metabolic and perceptual demands were higher in FW and EO compared with MS, DS and PJ, (b) neuromuscular fatigue was consistent up to 48 hours post exercise in all protocols, and

This study examined the effect of microcycles in eccentric strength and high-intensity interval training (HIT) on sleep parameters and subjective ratings. Forty-two well-trained athletes (mean age 23.2 ± 2.4 years) were either assigned to the strength (n = 21; mean age 23.6 ± 2.1 years) or HIT (n = 21; mean age 22.8 ± 2.6 years) protocol. Sleep monitoring was conducted with multi-sensor actigraphy (SenseWear Armband™, Bodymedia, Pittsburg, PA, USA) and sleep log for 14 days. After a five-day baseline phase, participants completed either eccentric accented strength or high-intensity interval training for six days, with two training sessions per day. This training phase was divided into two halves (part 1 and 2) for statistical analyses. A three-day post phase concluded the monitoring. The Recovery-Stress Questionnaire for Athletes was applied at baseline, end of part 2, and at the last post-day. Mood ratings were decreased during training, but returned to baseline values afterwards in both groups. Sleep parameters in the strength group remained constant over the entire process. The HIT group showed trends of unfavourable sleep during the training phase (e.g., objective sleep efficiency at part 2: mean = 83.6 ± 7.8%, F3,60 = 2.57, P = 0.06, [Formula: see text] = 0.114) and subjective improvements during the post phase for awakenings (F3,60 = 2.96, P = 0.04, [Formula: see text] = 0.129) and restfulness of sleep (F3,60 = 9.21, P < 0.001, [Formula: see text] = 0.315). Thus, the HIT protocol seems to increase higher recovery demands than strength training, and sufficient sleep time should be emphasised and monitored.

Our study aimed to evaluate the acute responses and exercise-induced muscle damage of five different high-intensity interval training (HIIT) protocols adjusted by the maximum velocity obtained in the 30-15 Intermittent Fitness Test (VIFT).Sixteen well-trained intermittent sport players (mean ± SD; age, 24.6±2.7 years; V̇O2max, 58.3±5.9 mL/kg/min) participated in five different HIIT protocols separated by six days in between (P240: 4×4 min at 80% VIFT; P120: 7×2 min at 85%; P30: 2×10×30 s at 90%; P15: 3×9×15 s at 95%; P5: 4×6×5 s sprints). Blood lactate (La), blood pH, serum creatine kinase (CK), heart rate (HR), session rating of perceived exertion (session-RPE), delayed onset muscle soreness (DOMS) and countermovement jump (CMJ) height were measured.A significant main effect for protocol (P0.05) was found for the acute responses of HR, session-RPE and La with values increasing in longer intervals from P15 to P120 and P240 while blood pH responded inversely. In contrast, P5 produced the highest La concentration and blood pH decreases. Twenty-four-hour post-exercise CK, DOMS and the decrease in CMJ height were significantly higher after P5 compared to all other protocols (P0.05).HIIT protocols of different interval duration and intensity result in varying acute physiological and perceptual demands and exercise-induced muscle damage. Longer intervals with submaximal intensity lead to higher acute cardio circulatory responses, whereas sprint protocols induce the highest muscle damage and muscle soreness.

Die Leistungsentwicklung im Rahmen eines High-Intensity Ausdauertrainings (HIT) steht in ständiger Wechselwirkung mit den durch die hohen Reizintensitäten ausgelösten Ermüdungs- und Erholungsprozesse. Erfolgt keine adäquate Steuerung von Belastung und Erholung, nimmt das Risiko für chronische Überlastungsreaktionen zu. Daher war das Ziel dieser Dissertation, evidenzbasierte Praxisleitlinien für eine Belastungs- und Erholungssteuerung im HIT zu erarbeiten. Die Ergebnisse zeigten, dass (1.) die akuten Belastungs- und mittelfristigen Ermüdungsreaktionen zwischen unterschiedlichen praxisüblichen HIT-Protokollen teils erheblich variieren, (2.) die Sprungleistung, Muskelkontraktilität, Creatinkinase-Aktivität sowie eine subjektive Empfindensdiagnostik praktikable und potentiell sensitive Parameter zur Diagnostik von Beanspruchung und Ermüdung im HIT sind und (3.) eine aktive Erholung weder messbaren Vor- noch Nachteil hinsichtlich des Regenerationsprozesses nach HIT besitzt.

Raeder, C, Wiewelhove, T, Simola, RADP, Kellmann, M, Meyer, T, Pfeiffer, M, and Ferrauti, A. Assessment of fatigue and recovery in male and female athletes after 6 days of intensified strength training. J Strength Cond Res 30(12): 3412-3427, 2016-This study aimed to analyze changes of neuromuscular, physiological, and perceptual markers for routine assessment of fatigue and recovery in high-resistance strength training. Fourteen male and 9 female athletes participated in a 6-day intensified strength training microcycle (STM) designed to purposefully overreach. Maximal dynamic strength (estimated 1 repetition maximum [1RMest]; criterion measure of fatigue and recovery); maximal voluntary isometric strength (MVIC); countermovement jump (CMJ) height; multiple rebound jump (MRJ) height; jump efficiency (reactive strength index, RSI); muscle contractile properties using tensiomyography including muscle displacement (Dm), delay time (Td), contraction time (Tc), and contraction velocity (V90); serum concentration of creatine kinase (CK); perceived muscle soreness (delayed-onset muscle soreness, DOMS) and perceived recovery (physical performance capability, PPC); and stress (MS) were measured before and after the STM and after 3 days of recovery. After completing the STM, there were significant (p ≤ 0.05) performance decreases in 1RMest (%[INCREMENT] ± 90% confidence limits, ES = effect size; -7.5 ± 3.5, ES = -0.21), MVIC (-8.2 ± 4.9, ES = -0.24), CMJ (-6.4 ± 2.1, ES = -0.34), MRJ (-10.5 ± 3.3, ES = -0.66), and RSI (-11.2 ± 3.8, ES = -0.73), as well as significantly reduced muscle contractile properties (Dm, -14.5 ± 5.3, ES = -0.60; V90, -15.5 ± 4.9, ES = -0.62). After days of recovery, a significant return to baseline values could be observed in 1RMest (4.3 ± 2.8, ES = 0.12), CMJ (5.2 ± 2.2, ES = 0.28), and MRJ (4.9 ± 3.8, ES = 0.32), whereas RSI (-7.9 ± 4.5, ES = -0.50), Dm (-14.7 ± 4.8, ES = -0.61), and V90 (-15.3 ± 4.7, ES = -0.66) remained significantly reduced. The STM also induced significant changes of large practical relevance in CK, DOMS, PPC, and MS before to after training and after the recovery period. The markers Td and Tc remained unaffected throughout the STM. Moreover, the accuracy of selected markers for assessment of fatigue and recovery in relation to 1RMest derived from a contingency table was inadequate. Correlational analyses also revealed no significant relationships between changes in 1RMest and all analyzed markers. In conclusion, mean changes of performance markers and CK, DOMS, PPC, and MS may be attributed to STM-induced fatigue and subsequent recovery. However, given the insufficient accuracy of markers for differentiation between fatigue and recovery, their potential applicability needs to be confirmed at the individual level.

Purpose:To investigate the effect of repeated use of active recovery during a 4-d shock microcycle with 7 high-intensity interval-training (HIT) sessions on markers of fatigue. Methods:Eight elite male junior tennis players (age 15.1 ± 1.4 y) with an international ranking between 59 and 907 (International Tennis Federation) participated in this study. After each training session, they completed 15 min of either moderate jogging (active recovery [ACT]) or passive recovery (PAS) with a crossover design, which was interrupted by a 4-mo washout period. Countermovement-jump (CMJ) height, serum concentration of creatine kinase (CK), delayed-onset muscle soreness (DOMS), and perceived recovery and stress (Short Recovery and Stress Scale) were measured 24 h before and 24 h after the training program. Results:The HIT shock microcycle induced a large decrease in CMJ performance (ACT: effect size [ES] = –1.39, P < .05; PAS: ES = –1.42, P < .05) and perceived recovery (ACT: ES = –1.79, P < .05; PAS: ES = –2.39, P < .05), as well as a moderate to large increase in CK levels (ACT: ES = 0.76, P > .05; PAS: ES = 0.81, P >.05), DOMS (ACT: ES = 2.02, P < .05; PAS: ES = 2.17, P < .05), and perceived stress (ACT: ES = 1.98, P < .05; PAS: ES = 3.06, P < .05), compared with the values before the intervention. However, no significant recovery intervention × time interactions or meaningful differences in changes were noted in any of the markers between ACT and PAS. Conclusions:Repeated use of individualized ACT, consisting of 15 min of moderate jogging, after finishing each training session during an HIT shock microcycle did not affect exercise-induced fatigue.

The aim of this study was to compare the effects of high-intensity interval training (HIIT) and repeated-sprint training (RST) on aerobic fitness, tennis-specific endurance, linear and repeated-sprint ability (RSA), and jumping ability. Thirty-one competitive male tennis players took part in a training intervention of 6 weeks. The players were matched into 3 groups, HIIT (n = 11), RST (n = 12), or control group (CON, n = 9). The results showed significant time × intervention interactions for VO(2)peak, with a significant increase in the VO(2)peak level of 6.0% in HIIT (p = 0.008) and 4.9% in RST (p = 0.010), whereas no changes occurred in CON. However, the following differences were found between the intervention groups: The HIIT-induced greater improvements in tennis-specific endurance (HIIT 28.9% vs. RST 14.5%; p < 0.05) and RST led to a significant improvement in RSA (i.e., reduction in the mean sprint time of 3.8%; p < 0.05). Neither training strategy induced any effects on jumping and sprinting abilities. Both training interventions showed similar improvements in general aerobic fitness. Also, the present results suggest that RST represents a time-efficient stimulus for a simultaneous improvement of general and tennis-specific aerobic fitness as well for RSA.

Our study aimed to evaluate the acute responses and exercise--induced muscle damage of five different high--intensity interval training (HIT) protocols adjusted by the maximum velocity obtained in the 30--15 Intermittent Fitness Test (V IFT ).Sixteen well--trained intermittent sport players (mean ± SD;; age, 24.6 ± 2.7 years; V̇O 2max , 58.3 ± 5.9 ml∙min∙kg --1 ) participated in five different HIT protocols separated by six days in between (P 240 : 4×4 min at 80% V IFT ; P 120 : 7×2 min at 85%; P 30 : 2×10×30 s at 90%; P 15 : 3×9×15 s at 95%; P 5 : 4×6×5 s sprints). Blood lactate (La), blood pH, serum creatinkinase (CK), heart rate (HR), session rating of perceived exertion (session--RPE), delayed onset muscle soreness (DOMS) and countermovement jump (CMJ) height were measured.A significant main effect for protocol ( p0.05) was found for the acute responses of HR, session-RPE and La with values increasing in longer intervals from P 15 to P 120 and P 240 while blood pH responded inversely. In contrast, P 5 produced the highest La concentration and blood pH decreases. 24 h post exercise CK, DOMS and the decrease in CMJ height were significantly higher after P 5 compared to all other protocols ( p0.05).HIT protocols of different interval duration and intensity result in varying acute physiological and perceptual demands and exercise--induced muscle damage. Longer intervals with submaximal intensity lead to higher acute cardio circulatory responses, whereas sprint protocols induce the highest muscle damage and muscle soreness.