Repeated-sprint sets test: a new method for evaluating and forecasting fitness in elite young male soccer players.

The objective of the current study was to explore the correlation between repeated sprint sets (RSS) ability and several physical attributes, including maximum sprint speed, maximal aerobic speed, maximal anaerobic speed, aerobic capacity, and explosive strength. Moreover, the aim was to assess the suitability of RSS as a comprehensive evaluation tool for physical qualities and to determine which physical field tests most accurately predict RSS in elite young male soccer players. A total of thirty-two young elite male soccer players (mean age 14.6 ± 0.3 years; predicted years from peak height velocity (PHV): - 0.4 ± 0.3; years in training: 3.7 ± 0.5) voluntarily participated in the study. The players participated in eight consecutive specific physical tests, with a minimum 72-h recovery between each session to minimize the impact of fatigue during the second trial. The participants completed the tests in the following order: RSS test, Vam-Eval test, a constant velocity test performed until exhaustion at 100% of vVO2max (tlim100), 20-m Multi-Stage Shuttle Run test (VMSRT), Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), Maximal Anaerobic Shuttle Running Test (VMASRT), Maximal Sprinting Speed Test (20-m flying sprint), Countermovement Jump (CMJ), and Standing Long Jump test (SLJ). The results of the study showed that there were very large negative correlations between tlim100 and SST (sum of sprint times), and large negative correlations between Yo-Yo IR1, Vam-Eval, and SST during RSS in young elite male soccer players (p < 0.05). Additionally, VMASRT and SLJ demonstrated a moderate negative correlation with SST (p < 0.05). In contrast, significant positive correlations were found between 20-m flying sprint and the SST (p < 0.05). According to the stepwise multiple linear regression analysis, the primary predictors of SST, ranked by importance, were tlim100 and Yo-Yo IR1. These two predictors collectively accounted for 72% of the variance in players' SST (p < 0.0001). Due to the importance of aerobic capacity and short repeated accelerations/sprint sets for overall competitive performance in soccer, in conclusion, our results suggest that elite young male soccer players should perform both high intensity interval training and aeorobic capactity exercises as part of soccer training if the primary outcome is to improve repeated sprint ability performance.

An eight-weeks resistance training programme with elastic band increases some performance-related parameters in pubertal male volleyball players.

The main aim was to evaluate the changes in dynamic, reactive, and power strength, and balance (as volleyball performance-related parameters) in pubertal volleyball players when a part of their normal inseason training regimen was replaced by an elastic band training (EBT). 27 male elite volleyball players were randomly allocated to intervention (N = 14; 14.86 ± 0.52 years) or control group (N = 13; 14.74 ± 0.36 years). The intervention consisted of an 8-week EBT program focused on the training of the lower limb, with different volumes and intensities. Countermovement jump (CMJ) and standing long jump (SLJ) were used to assess the power strength, squat one repetition-maximum, and reactive strength index to assess dynamic and reactive strength, respectively. Also, the balance was assessed through different parameters of the foot centre of pressure (CoP) displacements obtained with a force platform. An ANOVA of repeated measurements and post-hoc tests evaluated differences between groups and between baseline and post-intervention. Dynamic and power (CMJ and SLJ) strength, and anteroposterior displacement of the CoP were improved after the intervention. The control group only improved the dynamic strength. No statistically significant difference (p > 0.05) were found in the rest of the variables. EBT improves jump performance and other volleyball performance-related parameters in adolescent male athletes and should be considered to complement regular volleyball in-season training.

Acute Effects of Different Plyometric and Strength Exercises on Balance Performance in Youth Weightlifters.

Background: High-intensity muscle actions have the potential to temporarily improve the performance which has been denoted as postactivation performance enhancement. Objectives: This study determined the acute effects of different stretch-shortening (fast vs. low) and strength (dynamic vs. isometric) exercises executed during one training session on subsequent balance performance in youth weightlifters. Materials and Methods: Sixteen male and female young weightlifters, aged 11.3±0.6years, performed four strength exercise conditions in randomized order, including dynamic strength (DYN; 3 sets of 3 repetitions of 10 RM) and isometric strength exercises (ISOM; 3 sets of maintaining 3s of 10 RM of back-squat), as well as fast (FSSC; 3 sets of 3 repetitions of 20-cm drop-jumps) and slow (SSSC; 3 sets of 3 hurdle jumps over a 20-cm obstacle) stretch-shortening cycle protocols. Balance performance was tested before and after each of the four exercise conditions in bipedal stance on an unstable surface (i.e., BOSU ball with flat side facing up) using two dependent variables, i.e., center of pressure surface area (CoP SA) and velocity (CoP V). Results: There was a significant effect of time on CoP SA and CoP V [F(1,60)=54.37, d=1.88, p<0.0001; F(1,60)=9.07, d=0.77, p=0.003]. In addition, a statistically significant effect of condition on CoP SA and CoP V [F(3,60)=11.81, d=1.53, p<0.0001; F(3,60)=7.36, d=1.21, p=0.0003] was observed. Statistically significant condition-by-time interactions were found for the balance parameters CoP SA (p<0.003, d=0.54) and CoP V (p<0.002, d=0.70). Specific to contrast analysis, all specified hypotheses were tested and demonstrated that FSSC yielded significantly greater improvements than all other conditions in CoP SA and CoP V [p<0.0001 (d=1.55); p=0.0004 (d=1.19), respectively]. In addition, FSSC yielded significantly greater improvements compared with the two conditions for both balance parameters [p<0.0001 (d=2.03); p<0.0001 (d=1.45)]. Conclusion: Fast stretch-shortening cycle exercises appear to be more effective to improve short-term balance performance in young weightlifters. Due to the importance of balance for overall competitive achievement in weightlifting, it is recommended that young weightlifters implement dynamic plyometric exercises in the fast stretch-shortening cycle during the warm-up to improve their balance performance.

Introducing a Navigation Algorithm for Reducing the Spread of Diseases in Public Transport Networks.

Reducing passenger flow through highly frequented bottlenecks in public transportation networks is a well-known urban planning problem. This issue has become even more relevant since the outbreak of the SARS-CoV-2 pandemic and the necessity for minimum distances between passengers. We propose an approach that allows to dynamically navigate passengers around dangerously crowded stations to better distribute the passenger load across an entire urban public transport network. This is achieved through the introduction of new constraints into routing requests, that enable the avoidance of specific nodes in a network. These requests consider walks, bikes, metros, subways, trams and buses as possible modes of transportation. An implementation of the approach is provided in cooperation with the Munich Travel Corporation (MVG) for the city of Munich, to simulate the effects on a real city's urban traffic flow. Among other factors, the impact on the travel time was simulated given that the two major exchange points in the network were to be avoided. With an increase from 26.5 to 26.8 minutes on the average travel time, the simulation suggests that the time penalty might be worth the safety benefits.

Listening to Preferred Music Improved Running Performance without Changing the Pacing Pattern during a 6 Minute Run Test with Young Male Adults.

Several studies have investigated the effects of music on both submaximal and maximal exercise performance at a constant work-rate. However, there is a lack of research that has examined the effects of music on the pacing strategy during self-paced exercise. The aim of this study was to examine the effects of preferred music on performance and pacing during a 6 min run test (6-MSPRT) in young male adults. Twenty healthy male participants volunteered for this study. They performed two randomly assigned trials (with or without music) of a 6-MSPRT three days apart. Mean running speed, the adopted pacing strategy, total distance covered (TDC), peak and mean heart rate (HRpeak, HRmean), blood lactate (3 min after the test), and rate of perceived exertion (RPE) were measured. Listening to preferred music during the 6-MSPRT resulted in significant TDC improvement (Δ10%; p = 0.016; effect size (ES) = 0.80). A significantly faster mean running speed was observed when listening to music compared with no music. The improvement of TDC in the present study is explained by a significant overall increase in speed (main effect for conditions) during the music trial. Music failed to modify pacing patterns as suggested by the similar reversed "J-shaped" profile during the two conditions. Blood-lactate concentrations were significantly reduced by 9% (p = 0.006, ES = 1.09) after the 6-MSPRT with music compared to those in the control condition. No statistically significant differences were found between the test conditions for HRpeak, HRmean, and RPE. Therefore, listening to preferred music can have positive effects on exercise performance during the 6-MSPRT, such as greater TDC, faster running speeds, and reduced blood lactate levels but has no effect on the pacing strategy.

Normative Data and Physical Determinants of Multiple Sprint Sets in Young Soccer Players Aged 11-18 Years: Effect of Maturity Status.

Selmi, MA, Sassi, RH, Yahmed, MH, Giannini, S, Perroni, F, and Elloumi, M. Normative data and physical determinants of multiple sprint sets in young soccer players aged 11-18 years: Effect of maturity status. J Strength Cond Res 34(2): 506-515, 2020-The aims of the study were: (a) to establish normative data for repeated-sprint sets (RSS) test based on the maturity status (age at peak height velocity [PHV]) and (2) to investigate the relationship between anthropometrical variables (stature, sitting height, body mass, and body fat percentage), RSS (2 × 5 × 20 m with 15-second recovery between sprints and 1-minute recovery between sets), and fitness tests {squat jump, countermovement jump, standing long jump, standing triple jump, 5-jump test, and 20-m shuttle run (multistage shuttle run test [MSRT])}. Young male soccer players (n = 262; age: 14.5 ± 2.9 years) were evaluated and classified into 4 groups according to their maturity status: pre-PHV, circum-PHV1, circum-PHV2, post-PHV. An analysis of variance and Bonferroni post hoc were used to determine maturity group differences (p ≤ 0.05), whereas Pearson's correlation was used between variables. Repeated-sprint sets' indices (sum of sprint times [SST] and best sprint time [BST]) were significantly different between the maturity groups. Significant correlations between SST with body mass (from -0.73 to -0.33) and MSRT (from -0.49 to -0.30) among each maturity group were found. With the different maturity groups, correlations between SST (s), BST (s), and vertical jump (cm) (r = -0.63 to -0.25 and r = -0.68 to -0.23) and horizontal jump (m) (r = -0.70 to -0.38 and r = -0.63 to -0.43) were observed. Repeated-sprint sets' values improve during maturation of young soccer players and the correlations between RSS and fitness tests vary through the maturity groups. This information could be useful for the coach to identify talent and to prescribe specific physical training to improve performance.

Does Maturity Status Affect the Relationship Between Anaerobic Speed Reserve and Multiple Sprint Sets Performance in Young Soccer Players?

Selmi, MA, Al-Haddabi, B, Yahmed, MH, and Sassi, RH. Does maturity status affect the relationship between anaerobic speed reserve and multiple sprints sets performance in young soccer players? J Strength Cond Res 34(12): 3600-3606, 2020-The purpose of this study is to examine the relationship between repeated-sprint sets (RSS) performance indices and anaerobic speed reserve (ASR) in young soccer players of different maturity status. One hundred seventy-nine young male soccer players (11.1-17.8 years) classified as pre- (n = 50), circum- (n = 60), or post- (n = 69) peak height velocity (PHV) performed multistage shuttle run test (MSRT) to measure maximal aerobic speed (MAS), 30-m sprint with 10-m splits to estimate maximal anaerobic speed (MAnS), and RSS test. Anaerobic speed reserve was calculated as the difference between MAS and MAnS. The RSS indices, MAS, MAnS, and ASR were significantly different in the 3 maturity groups (p < 0.001; effect size = 0.12-0.64). Correlations between RSS performance indices and ASR varied considerably depending on maturity status. Very large correlations between ASR and RSS indices expressed as sum sprint time (SST) and best sprint time (BST) were found for pre- and circum-PHV groups (r = -0.76, -0.79 and r = -0.82, -0.86, respectively). In the post-PHV group, ASR was moderately associated with both SST (r = -0.45) and BST (r = -0.46). To sum up, these results highlighted that the ASR is more related to factors of RSS performance in pre- and circum-PHV male soccer players compared with post-PHV ones. These findings could help coaches and strength and conditioning professionals to better understand how the relationship between ASR and RSS evolves across the maturity and may be considered, therefore, useful in youth soccer selection/training process.

Maturity Status as a Determinant of the Relationships Between Conditioning Qualities and Preplanned Agility in Young Handball Athletes.

Hammami, R, Sekulic, D, Selmi, MA, Fadhloun, M, Spasic, M, Uljevic, O, and Chaouachi, A. Maturity status as a determinant of the relationships between conditioning qualities and preplanned agility in young handball athletes. J Strength Cond Res 32(8): 2302-2313, 2018-Studies performed thus far have not accounted for the potential influence of maturity on determinants of preplanned agility. This study aimed to examine how determinants of preplanned agility are affected by the period of peak height velocity (PHV) regarding the anthropometrics and conditioning qualities in young handball players. The sample comprised 56 handball players (male; 12-14 years of age), allocated into 2 groups according to their biological age of maturity: Pre-PHV (N = 34) and Post-PHV (N = 22). Players were evaluated on handball-specific tests of preplanned agility (CODAT and T-HALF). Predictors included anthropometrics, sprinting, horizontal and vertical jumps, and reactive strength index (RSI). The reliability of the tests was appropriate (intraclass correlation coefficient: 0.87-0.95; coefficient of variation: 4.4-5.8%). In the Pre-PHV group, 67% variance of the T-HALF accounted for horizontal countermovement jump (ß: -0.83, p < 0.01), 20-m sprint (ß: 0.91, p < 0.01), and body mass (ß: 0.19, p = 0.02). In the Post-PHV group, 80% of the T-HALF variance was explained, with a significant influence of 20-m sprint (ß: 0.52, p < 0.01), RSI (ß: -0.24, p = 0.04), and standing long jump (ß: -0.57, p = 0.03). In the Pre-PHV group, 45% of the CODAT variance accounted for the partial influence of body fat percentage (ß: 0.44, p = 0.04) and a 20-m sprint (ß: 0.74, p < 0.01). In the Post-PHV group, the predictors accounted for 79% of the CODAT variance, with a significant influence of the RSI (ß: -0.26, p = 0.04) and a 10-m sprint (ß: 0.87, p = 0.03). Our results reinforce the need for differential strength and conditioning programs aimed at improving the preplanned agility of young athletes who differ in maturity status.

Relationship Between Repeated Sprint Performance and both Aerobic and Anaerobic Fitness.

The aims of this study were firstly, to examine the relationship between repeated sprint performance indices and anaerobic speed reserve (AnSR), aerobic fitness and anaerobic power and secondly, to identify the best predictors of sprinting ability among these parameters. Twenty nine subjects (age: 22.5 ± 1.6 years, body height: 1.8 ± 0.1 m, body mass: 68.8 ± 8.5 kg, body mass index (BMI): 22.2 ± 2.1 kg•m-2, fat mass: 11.3 ± 2.9 %) participated in this study. All participants performed a 30 m sprint test (T30) from which we calculated the maximal anaerobic speed (MAnS), vertical and horizontal jumps, 20m multi-stage shuttle run test (MSRT) and repeated sprint test (10 × 15 m shuttle run). AnSR was calculated as the difference between MAnS and the maximal speed reached in the MSRT. Blood lactate sampling was performed 3 min after the RSA protocol. There was no significant correlation between repeated sprint indices (total time (TT); peak time (PT), fatigue index (FI)) and both estimated VO2max and vertical jump performance). TT and PT were significantly correlated with T30 (r=0.63, p=0.001 and r=0.62, p=0.001; respectively), horizontal jump performance (r = -0.47, p = 0.001 and r = -0.49, p = 0.006; respectively) and AnSR (r=-0.68, p= 0.001 and r=-0.70, p=0.001, respectively). Significant correlations were found between blood lactate concentration and TT, PT, and AnSR (r=-0.44, p=0.017; r=-0.43, p=0.018 and r=0.44, p=0.016; respectively). Stepwise multiple regression analyses demonstrated that AnSR was the only significant predictor of the TT and PT, explaining 47% and 50% of the shared variance, respectively. Our findings are of particular interest for coaches and fitness trainers in order to predict repeated sprint performance by using AnSR that can easily identify the respective upper performance limits supported by aerobic and anaerobic power of a player involved in multi-sprint team sports.

Physiological Responses and Performance Analysis Difference between Official and Simulated Karate Combat Conditions.

PURPOSE: This study aimed to compare physiological responses and time-motion analysis between official and simulated karate combat. METHODS: Ten high-level karatekas participated in this study, which included official and simulated karate combat. RESULTS: Karatekas used more upper-limb attack techniques during official combat compared to simulated ones (6±3 vs 3±1; P=0.05, respectively). For official and simulated karate matches, the numbers of high-intensity actions (i.e. offensive and defensive fighting activity) were 14±6 and 18±5, respectively (P>0.05), lasting from <1s to 5s each. Total fighting activity phase was lower during official compared to simulated matches (21.0±8.2s vs 30.4±9.9s, P<0.01, respectively). Effort (10.0±2.8s) to rest (11.9±2.7s) ratio (E:R) was 1:1 and high-intensity actions (1.6±0.3s) to rest (11.9±2.7s) ratio was higher than 1:7 during simulated combat. During official karate match, the activity and rest duration were 10.0±3.4s and 16.2±4.1s, respectively (E:R ratio 1:1.5), while high-intensity actions were 1.5±0.3s, resulting in an E:R ratio of 1:11. Blood lactate concentration was higher during official (11.14±1.82 mmol.l(-1)) compared to simulated karate combat (7.80±2.66 mmol.l(-1)) (P<0.05). Subjective perceived exertion differed significantly between official and simulated combat (14±2 vs. 12±2; P<0.05, respectively). The majority of karatekas' perceived exertion was higher in the lower limb muscle groups irrespective of the karate combat condition. CONCLUSION: Official and simulated matches differ considerably, therefore coaches should create new strategies during training sessions to achieve the same effort and pause profile of competitive matches and/or that athletes should be submitted to frequent competitions to adapt themselves to the profile of this event.

Time-motion analysis and physiological responses to karate official combat sessions: is there a difference between winners and defeated karatekas?

PURPOSE: The aim of this study was to measure and compare physiological and time-motion variables during karate fighting and to assess eventual differences between winners and defeated elite karatekas in an ecologically valid environment. METHODS: Fourteen elite male karatekas who regularly participated in national and international events took part in a national-level competition. RESULTS: There were no significant differences between winners and defeated karatekas regarding all the studied variables. Karatekas used more upper-limb (76.19%) than lower-limb techniques (23.80%). The kisami-zuki represented the most frequent technique, with 29.1% of all used techniques. The duration of each fighting activity ranged from <1 s to 5 s, with 83.8% ± 12.0% of the actions lasting less than 2 s. Karatekas executed 17 ± 7 high-intensity actions per fight, which corresponded to ~6 high-intensity actions per min. Action-to-rest ratio was about 1:1.5, and high-intensity-action- to-rest ratio was ~1:10. The mean blood lactate response at 3 min postcombat (Lapost) elicited during karate fighting was 11.18 ± 2.21 mmol/L (difference between Lapre and Lapost = 10.01 ± 1.81 mmol/L). Mean heart rate (HR) was 177 ± 14 beats/min (91% ± 5% of HRpeak). Karatekas spent 65% of the time exercising at HR >90% of the individual HRpeak. CONCLUSION: Karatekas predominantly use upper-limb karate techniques. Karate's nature is intermittent, with fighting activities representing ~6% of total combat's duration and ~84% of actions lasting less than 2 s, with ~21-s mean time interval in between. Kumite combat sessions induced high La and near-maximal cardiovascular strain. Other key success factors should be investigated to properly discriminate winners and defeated athletes.

Primary testicular non-Hodgkin lymphoma. a 10-year Tunisian single-institute experience.

BACKGROUND: Primary testicular non-Hodgkin lymphoma (NHL) is an uncommon extra nodal presentation, accounting for 1% of all NHL and 1 to 9% of testicular neoplasms. Median age at time of presentation is 60 years old. Anthracycline based chemotherapies are most frequently used. AIM: To analyze baseline characteristics, treatment modalities and survival of six cases of primary testicular non-Hodgkin lymphoma. METHODS: We screened 46 testicular neoplasm cases registered from January 1999 to January 2009 and found six primary testicular lymphoma patients. These six cases were analyzed for baseline clinical features, investigations, treatment and outcome variables. RESULTS: Median age was 50 years old and median duration of symptoms was 4 months. All patients had testicular swelling. Four patients had abdominal lymphadenopathy. Most patients had diffuse large B-cell histology. All patients underwent high inguinal orchidectomy and five were treated with anthracycline based chemotherapy. Four patients completed therapy and one of them relapsed two years later. CONCLUSION: Primary testicular NHL is an uncommon entity and with current combined modality treatment, the outcome may be as good as nodal NHL.

[Emphysematous pyelonephritis. Epidemiological, clinical, biological, bacteriological, radiological, therapeutic and prognostic features. Retrospective study of 30 cases]. / La pyélonéphrite emphysémateuse. Particularités épidémiologiques, clinico-biologiques, bactériologiques, radiologiques, thérapeutiques et évolutives. Etude rétrospective de 30 cas.

BACKGROUND: Emphysematous pyelonephritis is an uncommon, necrotizing bacterial infection of the kidney. It is a severe, life threatening affection. AIMS: To study the epidemiological, clinical, biological, bacteriological and radiological features of this affection, and to describe its therapeutic management and prognostic characteristics. METHODS: We conducted a retrospective study including 30 patients who were treated for an emphysematous pyelonephritis, in Charles Nicolle hospital department of urology, from 1987 to 2009. RESULTS: Emphysematous pyelonephritis generally affects adults. It is especially favored by diabetes and urinary tract obstruction. Escherichia coli is the main causative agent. Uroscan is the key of diagnosis. It is both medical and surgical emergency; the treatment combines intensive care with appropriate antibiotics and often drainage. Nephrectomy may be necessary from the outset, or after drainage failure. Prognosis is poor, with a high mortality rate (23 %), in our series. CONCLUSION: Management of emphysematous pyelonephritis poses real problems. This affection is still threatening, despite of advances in intensive care.

[Lethal osteo-chondro-dysplasia: feto-pathological study of 32 cases]. / Les ostéochondrodysplasies létales: etude foetopathologique de 32 cas.

BACKGROUND: The lethal osteochondrodysplasias are rare, their prevalence is estimated at 1 per 10 000 births. Mostly have genetic determinism. AIMS: To describe the malformations and dysmorphic features in lethal osteochondrodysplasias METHODS: Our study involved 32 cases of lethal fetal Osteochondrodysplasias, collected over a period of 14 years in the pathological department of Sousse. RESULTS: Our series consisted of 23 foetuses from a medical termination of pregnancy, 6 newborns and 3 stillbirths. The mean age of mothers was 28 years old, consanguinity was observed in 61%. 3 cases of recurrence of the disease in three families were noted. The bone abnormalities were detected in antenatal ultrasonography in 25 cases (87%) and at birth in 7 cases. Ultrasound showed micromelia in all cases, a narrow chest in 5 cases and spina bifida in 3 cases. The feto-pathological exam, including a macroscopic examination, radiological and histological samples of bone, has allowed us, based on the International Classification of 2001 to classify the 32 cases of Osteochondrodysplasias in: 8 cases of Achondrogenesis type I (type Parenti-Fraccaro), 3 cases of Achondrogenesis type II (Langer Saldino), 9 cases of lethal osteogenesis imperfecta, 8 cases of thanatophoric dysplasia, 4 cases of Schneckenbecken dysplasia, 2 cases of Short rib polydactyly syndrome, Majewski type and 1 case of asphyxiating thoracic dysplasia.

Seminal vesicle abscess: report of a new case.

BACKGROUND: Seminal vesicle abscess (SVA) is a rare pathologic entity, usually diagnosed by transrectal ultrasonography and computerized tomography scan. AIM: Report a new case. CASE REPORT: We report the successful management of a seminal vesicle abscess with percutaneous transvesical drainage in a 60-year-old diabetic patient. Computed tomography scan has been used for the diagnosis and the guidance of the percutaneous drainage. CONCLUSION: Seminal vesicle abscess is a very rare pathology with no specific symptoms. Transvesical drainage can be proposed successfully.