Match-Play Running Performance in Professional Male Soccer Players: The Role of Anaerobic Speed Reserve

Purpose: This study aimed to compare match-play running performance between players with a high (HASR) and low (LASR) anaerobic speed reserve (ASR) profile in professional soccer players. Method: Thirty-six male players from the same club (age: 23.3 ± 5.4 years) took part in this study. Match data were collected from 43 home matches of the first and second division of the Brazilian National Championship over two consecutive seasons. Players had their maximal sprinting (MSS) and aerobic speeds (MAS) determined during field test-based assessments. ASR was defined as MSS minus MAS. Total distance (TD), sprinting distance, number of accelerations and decelerations, absolute peak (PMS(abs)) and mean match sprint speed (MMSS(abs)) and its relative values expressed as a percentage of MSS (PMS(rel) and MMSS(rel)), distance covered > 100% MAS(abs) and > 50% MSS(abs) were compared between the groups and halves. Results: HASR presented greater sprint demand (d > 0.80), PMS(abs) (d = 1.57), and MMSS(abs) (d = 0.99) than the LASR group. The opposite was observed for PMS(rel) and MMSS(rel). The TD and amount of high-intensity accelerations and decelerations were moderately (0.77MAS(abs) and > 50% MSS(abs) decreased between halves (d = 0.72 and 0.77), while the HASR did not (d < 0.10). Conclusion: Our findings indicated that players with larger ASR had greater sprint demand, with a lower relative running intensity, and covered longer distances above MAS. The amplitude of ASR also affected the player's running ability between halves.

The Effects of a Supramaximal Intermittent Training Program on Aerobic and Anaerobic Running Measures in Junior Male Soccer Players

This study investigated the effectiveness of supplementing regular preseason soccer training with a supramaximal intermittent shuttle-run training (ISRT) model prescribed from Carminatti's Test peak speed (PST-CAR) in aerobic performance-related indices and sprinting speed in male junior soccer players. Twenty-three national-level soccer players (mean ± SD; age 18.07 ± 0.9 y, body height 1.76 ± 0.65 m, body mass 71.9 ± 8.7 kg) were assigned to either an experimental group (EG; n = 13) performing ISRT + soccer training or a control group (CG; n = 10) that followed regular preseason soccer training alone. The following tests were applied before and after the eight-week training intervention: (i) incremental treadmill tests (VO2max and lactate minimum speed - LMS); (ii) linear 30-m sprint test and Carminatti's Test (PST-CAR). Results indicated larger gains for the EG in LMS (Δ = 9.53% vs. 2.82%) and PST-CAR (Δ = 5.50% vs. 2.10%) than in the CG. Furthermore, changes in VO2max produced higher effect size (d) values for the EG (Δ = 6.67%; d = 0.59) than the CG (Δ = 1.88%; d = 0.18). Both groups improved (p = 0.002) their flying 20-m sprint speed (EG: Δ = 1.01%; CG: Δ = 1.56%). However, small decreases were observed for 10-m sprint speed in the CG (Δ = -2.19%; d = -0.44), while only trivial changes were noticed for the EG (Δ = -0.50%; d = -0.16). Our data support that additional supramaximal ISRT is an effective training stimulus to enhance aerobic performance-related indices and promote small improvements in maximal running speed without impairing the soccer players' acceleration capacity. This study also shows that PST-CAR can be useful for individualizing running intensity in supramaximal ISRT modes.

What Factors Discriminate Young Soccer Players Perceived as Promising and Less Promising by Their Coaches?

Purpose: This study aimed to verify whether there are differences in physical, technical, and tactical assessment outcomes derived from field-based tests and small-sided games (SSG) in addition to anthropometric and maturational characteristics between players classified as promising and less promising as per the coaches' perception. Method: A total of 53 male U-15 youth soccer players (age: 14.8 ± 0.2 years, weight: 61.7 ± 6.9 kg, height: 171.8 ± 6.7 cm) and three experienced coaches from three distinct sports clubs were enrolled in this study. Based on the coaches' perception, players were split into three group levels for both short- and long-term success ranking: (i) promising (PL; top 5 players; n = 15), (ii) intermediate (IL; n = 23) and (iii) less promising (LPL; 5 bottom players; n = 15). The following measures were determined: anthropometry, maturity offset, vertical jump, and aerobic-anaerobic running performance, soccer- specific skills tests, GPS-based running metrics, technical and tactical actions during SSG, and minutes played throughout the season. Results: There were no differences between groups for anthropometrical, maturational, and physical outcomes. PL players in both rankings covered more distances at sprinting and presented more offensive technical and tactical actions during SSG than their LPL peers. PL and IL presented more minutes played in competitive seasons than LPL of short-term ranking. Conclusion: The biggest differences between the players ranked by their coaches were apparent only during a representative game task, emphasizing the importance of SSG as a tool to assess the players' technical-tactical awareness. In addition to the SSG, the coach's eye plays a key role during the talent identification and selection process.

Modelling anaerobic peak power assessed by the force-velocity test among late adolescents

OBJECTIVES

The aim of this study was to examine the concurrent contributions of body size, estimates of whole-body composition, and appendicular volume in addition to participation in competitive basketball to explain inter-individual variance in anaerobic peak power output during late adolescence. The study also tested non-participation versus participation in basketball as an independent predictor of peak power output.

METHODS

The sample of this cross-sectional study was composed of 63 male participants (basketball: n=32, 17.0±0.9 years; school: n=31, 17.4±1.0 years). Anthropometry included stature, body mass, circumferences, lengths, and skinfolds. Fat-free mass was estimated from skinfolds and lower limbs volume predicted from circumferences and lengths. Participants completed the force-velocity test using a cycle ergometer to determine peak power output.

RESULTS

For the total sample, optimal peak power was correlated to body size (body mass: r=0.634; fat-free mass: r=0.719, lower limbs volume: r=0.577). The best model was given by fat-free mass and explained 51% of the inter-individual variance in force-velocity test. The preceding was independent of participating in sports (i.e., the dummy variable basketball vs. school did not add significant explained variance).

CONCLUSION

Adolescent basketball players were taller and heavier than school boys. The groups also differed in fat-free mass (school: 53.8±4.8 kg; basketball: 60.4±6.7 kg), which was the most prominent predictor of inter-individual variance in peak power output. Briefly, compared to school boys, participation in basketball was not associated with optimal differential braking force. Higher values in peak power output for basketball players were explained by a larger amount of fat-free mass.

The Effects of a Compensatory Training Program Adding an Isoinertial Device in the Shoulder Function on Young Tennis Players

ABSTRACT

Fernandez-Fernandez, J, Moreno-Perez, V, Cools, A, Nakamura, FY, Teixeira, AS, Ellenbecker, T, Johansson, F, and Sanz-Rivas, D. The effects of a compensatory training program adding an isoinertial device in the shoulder function on young tennis players. J Strength Cond Res 37(5): 1096-1103, 2023-The aim of this study was to analyze whether a compensatory training program, including isoinertial flywheel training, could reduce shoulder imbalances in a group of asymptomatic young tennis players. After an initial evaluation, 26 young tennis players were assigned to either a supervised flywheel training group (FTG, n = 13) or a control group (CG, n = 13). Shoulder passive internal (IR) and external rotation (ER) range of motion (ROM) as well as shoulder IR and ER maximal isometric strength were measured before and after a 12-week training intervention, performed 3 times per week. After the intervention, results showed significant changes for IR ( p < 0.001, effect size [ES] = 1.83) and ER ( p < 0.001, ES = 1.77) on the dominant (D) side, and IR on the nondominant (ND) side ( p < 0.001, ES = 2.24) in the FTG compared with the CG. Regarding the ROM values, results showed that the FTG achieved significantly greater increases for the IR ROM ( p < 0.001, ES = 3.32) and total ROM (TROM) ( p = 0.004, ES = 1.39) on the D and ND sides (IR ROM: p = 0.002, ES = 1.53; TROM: p < 0.001, ES = 2.35) than the CG. Moreover, the CG displayed larger decrements in ER ROM ( p = 0.016, ES = 1.12) on the ND side after the training period than the FTG. The conducted compensatory training program was effective to increase the ER strength and IR mobility of the FTG players, which led to a reduction in the glenohumeral imbalances.

Match activity profile and heart rate responses of top-level soccer referees during Brazilian National First and Second Division and regional championships

This study aimed to examine the differences in physical match activities and heart rate (HR) responses experienced by Brazilian field referees (FRs) and assistant referees (ARs) during official matches from three different championship levels (Serie A, Serie B and Regional). The sample was composed of 51 FRs (age: 36.3 ± 4.7 years) and 87 ARs (age: 35.0 ± 5.6 years). Match activities derived from Global Position System and HR response (expressed as average %HRmax) were collected during official soccer matches (91 and 146 individual observations for FRs and ARs, respectively). FRs and ARs covered higher distances at high-intensity running (HIR; d = 1.17 and 2.53, p < 0.001), sprinting (d = 0.82 and 0.48, p < 0.005) and high-intensity activities (HIA; d = 1.07 and 1.97, p < 0.001) in Serie A and Serie B than in Regional. Changes in the distances covered at HIR (0.80 < d < 3.25, p < 0.005), sprinting (d = 0.42, p = 0.050), and HIA (0.93 < d < 3.01, p < 0.005) from one half-match to the other were observed only in Serie A and Serie B for FRs and ARs. The average %HRmax was progressively increased in both half-matches for FRs (1.28 < d < 3.05, p < 0.003) and ARs (0.85 < d < 3.54, p < 0.001) during all championships. Serie A and Regional elicited higher average %HRmax (0.80 < d < 1.37, p < 0.030) than Serie B in FRs. For ARs, Serie A and Serie B elicited higher average %HRmax (2.14 < d < 3.87, p < 0.001) than Regional. In conclusion, the physical match activities and average %HRmax of Brazilian FRs and ARs differ across soccer championship levels. Thus, FRs and ARs require specific training for different championship levels. In particular, FRs and ARs acting in Regional soccer championships are likely to need specific preparation to support the higher physical demand observed at higher competition levels.

High-Intensity Intermittent Exercise Performed on the Sand Induces Higher Internal Load Demands in Soccer Players

This study aimed to examine the acute physiological effect of shuttle-run-based high-intensity intermittent exercise (HIIE) performed at the same relative speed (i. e., 100% PS_T-CAR) on sand (SAND) and grass (GRASS) in male junior soccer players. Seven Under-23 Brazilian national league ("Série A") soccer players completed four testing sessions in either SAND or GRASS surface condition. The first two testing sessions consisted of performing a maximal progressive shuttle-run field protocol until volitional exhaustion (Carminatti's test, T-CAR), whereas the third and fourth sessions comprised a HIIE session on each ground surface. The HIIE session consisted of three 5-min bouts [12 s shuttle-run (with a direction change every 6 s)/12 s of passive rest] performed at 100% of T-CAR peak speed (PS_T-CAR) with 3 min of passive recovery between sets. Measurements of oxygen uptake (VO₂), heart rate (HR), blood lactate concentration ([La]), and rating of perceived exertion (RPE) were performed during all conditions. The SAND condition elicited significantly higher %VO₂peak (94.58 ± 2.73 vs. 87.45 ± 3.31%, p < 0.001, d = 2.35), %HRpeak (93.89 ± 2.63 vs. 90.31 ± 2.87%, p < 0.001, d = 1.30), RPE (8.00 ± 0.91 vs. 4.95 ± 1.23 a.u., p < 0.001, d = 2.82), and [La] (10.76 ± 2.37 vs. 5.48 ± 1.13 mmol/L, p < 0.010, d = 2.84). This study showed that higher internal workloads are experienced by the players during a single HIIE session performed on a softer surface as SAND, even when the exercise intensity was individualized based on 100%PS_T-CAR.

Ecological and Construct Validity of a Repeated Sprint Test in Male Youth Soccer Players

ABSTRACT

Fernandes-Da-Silva, J, Castagna, C, Teixeira, AS, Carminatti, LJ, Francini, L, Póvoas, SCA, and Antonacci Guglielmo, LG. Ecological and construct validity of a repeated sprint test in male youth soccer players. J Strength Cond Res 35(7): 2000-2009, 2021-This study aimed to examine the relationship between a repeated sprint ability (RSA) test (5 bouts of 30-m sprints interspersed by 30 seconds of recovery) and match-related physical performance in male youth soccer players. Although 60 outfield players were evaluated, only data from players who participated in the full matches (n = 39) were retained (8 central defenders, 7 external defenders, 8 central midfielders, 8 external midfielders, and 8 forwards). To verify the ecological validity of this RSA protocol, the association between the best (RSAbest) and mean (RSAmean) sprint time in the 5 × 30-m and physical match performance during friendly youth soccer games was examined. Physical match demands were assessed using global positioning system technology (10 Hz) considering distance covered in selected arbitrary speed categories. The absolute speed thresholds were the same for all the players. Players were categorized into 2 groups based on the 5 × 30-m performance: RSAmean times below (i.e., faster) and above (i.e., slower) the median value. Players with faster RSAmean times covered significantly more distance sprinting during friendly matches (606 ± 204 m, +47.0%; t = 4.953; effect size = 1.88, 1.24; 2.52, p ≤ 0.001) compared to their slower counterparts (322 ± 145 m). A large negative correlation (r = -0.63, -0.77; -0.44, p ≤ 0.001) was found between RSAbest time (4.59 ± 0.27 seconds) and match sprint distance (457 ± 229 m). Likewise, RSAmean time (4.76 ± 0.25 seconds) was also largely associated (r = -0.60, -0.75; -0.39; p ≤ 0.001) with in-game sprinting performance. The results of this study provided evidence to support the construct and ecological validity of the 5 × 30-m protocol in male youth soccer players. Furthermore, differences in 5 × 30-m performance explained the amount of sprinting activity performed during the match.

Phase Angle Is Related to 10 m and 30 m Sprint Time and Repeated-Sprint Ability in Young Male Soccer Players

OBJECTIVE

To examine the association between phase angle (PhA) and bioelectrical impedance vector analysis (BIVA) and components of physical performance in male youth soccer players.

DESIGN

Cross-sectional.

METHODS

Sixty-two players from two professional soccer academies were recruited. Electrical bioimpedance was used to obtain the PhA and BIVA. Body fat (BF) and lean soft tissue mass (LSTM) were measured by dual-energy X-ray absorptiometry. All players completed physical tests including the standing long jump (SLJ), Carminatti's test (peak speed at the end of the test, PST-CAR), 10 m and 30 m straight-line sprints, and repeated-sprint ability (RSA) test (RSAbest and RSAmean times).

RESULTS

Adjusting for chronological age, BF, and LSTM, multiple regression analysis outputs showed that PhA remained inversely related to RSAmean (β = -0.362; p < 0.001), RSAbest (β = -0.239; p = 0.020), 10 m (β = -0.379; p = 0.012), and 30 m (β = -0.438; p < 0.001) sprint times, while the association with PST-CAR and SLJ performance were statistically non-significant. In addition, BIVA showed that differences in confidence ellipses were found between athletes in the reference population and the study sample (p < 0.05). The tolerance ellipses indicated that the athletes in the present study had more total body water (TCW) and lower proportions of intracellular water (ICW) to extracellular water (ECW). The reference population had more TCW and ICW/ECW.

CONCLUSIONS

Our results suggest that young soccer players with higher PhA values, indicating better cell integrity and functionality, have better performance in typical anaerobic running activities, such as sprinting speed and RSA performance, adjusted to age and body composition characteristics.

HIIT Models in Addition to Training Load and Heart Rate Variability Are Related With Physiological and Performance Adaptations After 10-Weeks of Training in Young Futsal Players

INTRODUCTION

The present study aimed to investigate the effects of two high-intensity interval training (HIIT) shuttle-run-based models, over 10 weeks on aerobic, anaerobic, and neuromuscular parameters, and the association of the training load and heart rate variability (HRV) with the change in the measures in young futsal players.

METHODS

Eleven young male futsal players (age: 18.5 ± 1.1 years; body mass: 70.5 ± 5.7 kg) participated in this study. This pre-post study design was performed during a typical 10 weeks training period. HIIT sessions were conducted at 86% (HIIT86; n = 6) and 100% (HIIT100; n = 5) of peak speed of the FIET. Additionally, friendly and official matches, technical-tactical and strength-power training sessions were performed. Before and after the training period, all players performed the FIET, treadmill incremental, repeated sprint ability (RSA), sprint 15-m, and vertical jump tests (CMJ and SJ), and the HRV was measured. Training load (TL) was monitored using the session rating of perceived effort. Data analysis was carried out using Bayesian inference methods.

RESULTS

The HIIT86 model showed clear improvements for the peak oxygen uptake (VO2peak), peak speed in the treadmill incremental test, first and second ventilatory thresholds, RSA best and mean times, CMJ, and SJ. The HIIT100 model presented distinct advances in VO2peak, peak speed in the treadmill incremental test, RSA mean time, and CMJ. Between HIIT models comparisons showed more favorable probabilities of improvement for HIIT86 than HIIT100 model in all parameters. TL data and HIIT models strongly explained the changes in the RSA mean and best times (R 2 = 0.71 and 0.87, respectively), as well as HRV changes, and HIIT models explained positively VO2peak changes (R 2 = 0.72). All other changes in the parameters were low to moderately explained.

CONCLUSION

The HIIT86 proved to be more effective for improving aerobic, RSA, and neuromuscular parameters than HIIT100 during a typical 10-week futsal training period. So, strength and conditioning specialists prescribing shuttle-run intermittent exercises at submaximal intensities can manage the individual acceleration load imposed on athlete increasing or decreasing either the set duration or the frequency of change of direction during HIIT programming.

Tactical rule and pitch size change the physical and technical performance of young soccer players during small-sided games

Abstract The present study examined the effects of small-sided and conditioned games (SSCGs) manipulating tactical rules (ball-possession [BP] vs goal-scoring with goalkeepers [GS]) and pitch size (square [SP] vs rectangular [RP]) on the running performance and technical skills of young soccer players. Ten male soccer players (chronological age: 12.45 ± 0.51 years; body mass: 41.99 ± 7.97 kg; height: 152.85 ± 10.03 cm) were monitored using GPS units during SSCG formats. The distance covered at different running intensities and number of technical actions were used in analyses. SSCG-induced changes in 30 m sprint and CMJ performances were also evaluated. Compared to BP, GS elicited significantly lower distances covered at low intensity running (p=0.003; d=-0.95), more sprints (p=0.050; d=0.67), and longer distances covered in terms of walking (p=0.035; d=2.60) and sprinting (p=0.029; d=0.75); (ii) number of passes (short [p=0.002; d=1.10] and long [p=0.013; d=0.82]) were more frequent during BP than GS games, while RP game format allowed for greater occurrence of long passes (p=0.036; d=0.64) than under the SP condition; (iii) jumping and sprinting performance did not change (p>0.05) using different SSCG formats. In conclusion, GS games demand more sprint running episodes in terms of number and distance covered than BP games. In addition, RP game formats can be used to increase the occurrence of longer passes in young soccer players aged 11-13 years.

Physical Performance in Young Judo Athletes: Influence of Somatic Maturation, Growth, and Training Experience

Purpose: To determine the individual contributions of chronological age, somatic maturation, body size and composition, and training experience as indicators of performance in neuromuscular and judo-specific assessments in young athletes. Methods: Sixty-six youth judo athletes performed anthropometric measurements, neuromuscular tests-standing long jump test (SLJ), medicine ball throw test (MBT), handgrip strength test (HGS), and judo-specific tests-Special Judo Fitness test (SJFT) and Judogi Grip Isometric Strength Test (JGST_ISO). A multiple linear regression was used with the level of significance set at 5%. Results: The main results showed age-peak height velocity (PHV), body fat and training experience explained close to 20% of SJFT performance. Chronological age, age-PHV, height, body mass and body fat accounted for 42% of variance in JGST_ISO. Chronological age, body fat and training experience explained 35% of the variance in SLJ, while chronological age, body mass and body fat explained 53% of the variance in MBT. Finally, age-PHV, body mass and height explained 54% of the variance in HGS. Conclusion: Estimated age-PHV and growth variables explained moderate to large proportions of the variance in neuromuscular tests (with exception of SLJ), while both estimated age-PHV, training and growth variables were predictors of judo-specific performance.

Effects of Resisted Vs. Conventional Sprint Training on Physical Fitness in Young Elite Tennis Players

This study aimed to compare the effects of 6-week resisted sprint (RST) versus conventional (unresisted) sprint training (CG) on sprint time, change of direction (COD) speed, repeated sprint ability (RSA) and jump performance (countermovement jump (CMJ) and standing long jump (SLJ)) in male young tennis players. Twenty players (age: 16.5 ± 0.3 years; body mass: 72.2 ± 5.5 kg; body height: 180.6 ± 4.6 cm) were randomly assigned to one of the two groups: RST (n = 10) and CG (n = 10). The training program was similar for both groups consisting of acceleration and deceleration exercises at short distances (3-4 m), and speed and agility drills. The RST group used weighted vests or elastic cords during the exercises. After 6 weeks of intervention, both training regimes resulted in small-to-moderate improvements in acceleration and sprint ability (5, 10, 20 m), SLJ and CMJ performances, COD pivoting on both, the non-dominant (moderate effect) and the dominant (small effect) foot, and the percentage of decrement (small effects) during a RSA test. Between-group comparisons showed that the SLJ (Δ = 2.0%) and 5 m sprint time (Δ = 1.1%) improved more in the RST group compared with the CG group. This study showed that 6 weeks of RST or unresisted training are time-efficient training regimes for physical improvements in young male tennis players.

Comparison of maturation and physical performance in basketball athletes of different playing positions

Abstract The aim of this study was to compare the characteristics of somatic maturation, anthropometric and physical performance (vertical jump and aerobic power) in young basketball players of different playing positions (under 13 years) and analyze these relationships using Peak Height Velocity (PHV) as a measure of somatic maturation. For this, 26 male athletes were evaluated. Anthropometric variables were: body mass, standing and sitting height, and length of lower limbs. Maturation was determined by age at PHV. Physical performance was determined by lower limb power (counter movement jump - CMJ) and aerobic power (Intermittent Recovery Test) tests. MANOVA reported significant differences (p<0.05) among playing positions regarding variables Maturity Offset, estimated PHV age, standing height, sitting height, estimated leg length, body mass and Yo-Yo IR1. In addition, it was identified that point guards reached estimated PHV at later age than their peers who act as small forwards and centers. Regarding CMJ, no significant differences were identified among playing positions, but in relation to aerobic power, point guards and small forwards presented higher performance. These findings confirm that maturation has great effect on growth and physical performance measures and the estimated PHV age is an applicable tool in young athletes, mainly aiding professionals in structuring the teaching-learning- training process in this age group.

Different Pathways Leading up to the Same Futsal Competition: Individual and Inter-Team Variability in Loading Patterns and Preseason Training Adaptations

During the preseason, futsal players deal with large internal load, which may result in a reduction in physical performance. The aims of this study were to compare the session rating of perceived exertion training load (s-RPE TL) during the preseason between two teams; and to analyze the changes on the delayed-onset muscle soreness (DOMS), aerobic- and speed-power characteristics in players accumulating different s-RPE TL (Low (LTL) vs. High (HTL)). Twenty-eight players (Team A, n = 15; Team B, n = 13) were recruited. The s-RPE TL was monitored throughout the preseason phase (five weeks) in both teams. The coaches of each team planned the activities that comprised their training programs, without any interference from the researchers. Team A evaluated countermovement jumps (CMJ) and DOMS weekly. Team B performed squat jumps (SJ), CMJ, 5 m and 15 m sprints, and a futsal intermittent endurance test (PV_FIET) before and after the preseason. Team B accumulated an almost-certainly greater s-RPE TL than Team A. In Team A, the CMJ height was likely to almost certainly improved for the HTL group from week 3. In Team B, the 5 m and 15 m sprint likely decreased after the preseason. Changes in 5 m (r = −0.61) and 15 m (r = −0.56) were correlated with total s-RPE TL. Changes in PV_FIET were positively associated with changes in sprint, but inversely related to the baseline. s-RPE TL differed between both teams, and substantial gains in neuromuscular performance were observed for the HTL group in Team A. Slower and faster players in Team B showed distinct intermittent-endurance and speed adaptive responses during the high-volume preseason.

Physiological Responses During the Time Limit at 100% of the Peak Velocity in the Carminatti's Test in Futsal Players

The aim of this study was to investigate the physiological responses during the time limit at the intensity of the peak velocity of the Carminatti's test (T-CAR). Ten professional futsal players (age, 27.4 ± 5.8 years, body mass, 78.8 ± 8.5 kg, body height, 175.8 ± 6.8 cm, body fat mass, 14.1 ± 2.6%) took part in the study. The players performed three tests, with an interval of at least 48 hours, as follows: the T-CAR to determine the peak velocity and the maximal heart rate; an incremental treadmill protocol to determine the maximal physiological responses; and a time limit running test at the peak velocity reached in the T-CAR. During the last two tests, a portable gas analyzer was used for direct measurement of cardiorespiratory variables. It was shown that the peak velocity was not significantly different from the maximal aerobic speed achieved in the laboratory (p = 0.213). All athletes reached their maximum oxygen uptake during the time limit test. The maximum oxygen uptake achieved during the time limit test was not different from that observed in the laboratory condition (51.1 ± 4.7 vs. 49.6 ± 4.7 ml·kg^-1·min^-1, respectively, p = 0.100). In addition, Bland and Altman plots evidenced acceptable agreement between them. On average, athletes took ~140 s to achieve maximum oxygen uptake and maintained it for ~180 s. Therefore, the peak velocity intensity can be used as an indicator of maximal aerobic power of futsal athletes and the time limit can be used as a reference for training prescription.

The peak velocity derived from the Carminatti Test is related to physical match performance in young soccer players

The aim of this study was to examine the relationship between the peak velocity derived from the Carminatti Test (T-CAR) (PV_T-CAR) and physical match performance in young soccer players. Thirty-three youth soccer players were recruited from 2 non-professional clubs. Friendly matches and small-sided game were performed. Physical match demands were assessed using Global Positioning System (GPS) technology. On a separate occasion, the players were submitted to the T-CAR. Players were categorised into 3 groups based on their T-CAR performance: Low (PV_T-CAR ≤ P33), Intermediate (P33 > PV_T-CAR < P66) and High (PV_T-CAR ≥ P66). The PV_T-CAR (15.5 ± 0.7 km·h^-1) was significantly related to high-intensity activities (HIA; r = 0.78, P < 0.001), high-intensity running (HIR; r = 0.66, P < 0.001), sprinting (r = 0.62, P < 0.001) and total distance (TD) covered (r = 0.47, P < 0.01) during friendly matches. The PV_T-CAR was strongly correlated with the amount of HIA (r = 0.81, P < 0.001), HIR (r = 0.85, P < 0.001) and TD covered (r = 0.81, P < 0.001) during small-sided game. No significant correlation was observed between the PV_T-CAR and distance of sprinting (r = 0.49, P = 0.067) during small-side game. Furthermore, players in the High group covered significantly more TD (10%) and did more HIA (42%), sprinting (31%) and HIR (25%) during friendly matches compared to the players classified as having Low performance on the T-CAR. These differences still remained after adjusting for chronological age (CA), maturity and body size. In conclusion, the current study gives empirical support to the ecological and construct validity of this novel field test (T-CAR) as an indicator of match-related physical performance in young soccer players during pubertal years.

Are the oxygen uptake and heart rate off-kinetics influenced by the intensity of prior exercise?

The aim of this study was to investigate the effect of prior exercise on the heart rate (HR) and oxygen uptake (VO2) off-kinetics after a subsequent high-intensity running exercise. Thirteen male futsal players (age 22.8±6.1years) performed a series of high-intensity bouts without prior exercise (control), preceded by a prior same intensity continuous exercise (CE+CE) and a prior sprint exercise (SE+CE). The magnitude of excess post-exercise oxygen consumption (EPOCm-4.25±0.19 vs. 3.69±0.20Lmin(-1) in CE+CE and 3.62±0.18Lmin(-1) in control; p<0.05) and the parasympathetic reactivation (HRR60s-33±3 vs. 37±3bpm in CE+CE and 42±3 bpm in control; p<0.05) in the SE+CE were higher and slower, compared with another two conditions. The EPOCτ (time to attain 63% of total response; 53±2s) and the heart rate time-course (HRτ-86±5s) were significantly longer after the SE+CE condition than control transition (48±2s and 69±5s, respectively; p<0.05). The SE+CE induce greater stress on the metabolic function, respiratory system and autonomic nervous system regulation during post-exercise recovery than CE, highlighting that the inclusion of sprint-based exercises can be an effective strategy to increase the total energy expenditure following an exercise session.

Apical MUC1 expression revealed on the foveolar epithelium in H. pylori gastritis

Background:

The membrane mucin MUC1 is altered in its pattern of expression in cancer, and also in other pathological situations, including Helicobacter pylori gastritis. Here we investigate the basis for the loss of apical staining of the gastric foveolar epithelium in H. pylori gastritis.

Methods:

MUC1 was examined in the gastric antrum from cases of H. pylori gastritis and normal controls. We used tissue sections that were either treated or not treated with periodate to effect deglycosylation, and the monoclonal antibodies LICRLonM8, MUSE-11, CT2 and BC2.

Results:

We show that the epitopes on the TR domain of MUC1 are partially cryptic due to glycosylation and that MUC1 is present on the apical surface of the gastric foveolar epithelium of gastritis patients.

Conclusion:

This observation suggests that there is no substantial loss of the mucin domain of MUC1 from the apical surface in gastritis, as suggested by others, but rather the H. pylori influences the glycosylation of MUC1. This paper highlights the issue of epitope specificity of monoclonal antibodies directed against disease-associated markers, specifically when they are glycoproteins, as is the case for many cancer markers.

Contribution of functional variation in the IL13 gene to allergy, hay fever and asthma in the NSHD longitudinal 1946 birth cohort

BACKGROUND

Genetic variants of the two adjacent genes, IL13 and IL4 have frequently been reported as being associated with susceptibility to atopy and asthma, both in adults and children, and some studies also suggest association with lung function and chronic obstructive pulmonary disease.

METHODS

In this study, we examined for the first time the effect of these variants in 2918 adults in a longitudinal birth cohort, the British National Survey of Health and Development, where there are extensive life style, developmental and environmental data. We examine two IL13 single nucleotide polymorphisms (SNPs) IL13 rs20541 (R110Q) and rs1800925 (-1024C>T) and one IL4 SNP, rs2070874 (-33C>T) with likely function.

RESULTS

We show that IL13 rs20541 and rs1800925 are each significantly associated with self-reported asthma and allergy, and that this association is not confounded by any of the known developmental and environmental risk factors for asthma and atopy, including in particular place of birth. IL13 rs20541 does however act as a confounder for the IL13 rs1800925 associations, meaning that there is no statistical support for rs1800925 having an independent effect. There is nevertheless evidence for interaction between smoking and rs1800925, with allergy as outcome. None of the SNPs showed association with measures of lung function, nor any interaction with the effect of smoking on lung function.

CONCLUSION

In a longitudinal population cohort we have established a role for polymorphism of IL13 in determining susceptibility to both atopy and asthma.

Isoenzyme electrophoretic patterns in discus fish (Symphysodon aequifasciatus Pellegrin, 1904 and Symphysodon discus Heckel, 1840) from the Central Amazon

The discus is a very popular and expensive aquarium fish belonging to the family Cichlidae, genus Symphysodon, formed by three Amazon basin endemic species: Symphysodon aequifasciatus, S. discus and S. tarzoo. The taxonomic status of these fish is very controversial, with a paucity of molecular research on their population genetic structure and species identification. Information on molecular genetic markers, especially isoenzymes, in search of a better understanding of the population genetic structure and correct identification of fish species, has been receiving more attention when elaborating and implementing commercial fishery management programs. Aiming to contribute to a better understanding of the species taxonomic status, the present study describes the isoenzymatic patterns of 6 enzymes: esterase (Est - EC 3.1.1.1), lactate dehydrogenase (Ldh - EC 1.1.1.27), malate dehydrogenase (Mdh - EC 1.1.1.37), phosphoglucomutase (Pgm - EC 5.4.2.2), phosphoglucose isomerase (Pgi - EC 5.3.1.9), and super oxide dismutase (Sod - EC 1.15.1.1) extracted from skeletal muscle specimens and analyzed by starch gel electrophoresis. Monomorphic patterns, presumably controlled by 11 loci: Est-1, Est-2, Est-3, Ldh-1, Ldh-2, Mdh-1, Mdh-2, Pgi-1, Pgi-2, Pgm-1, and Sod-1 were fixed for the same alleles: Est-1(1), Est-2(1), Est-3(1), Ldh-1(1), Ldh-2(1), Mdh-1(1), Mdh-2(1), Pgi-1(1), Pgi-2(1), Pgm-1(1), and Sod-1(1), respectively, and detected in all 60 specimens examined (27 S. aequifasciatus from Manacapuru and 33 S. discus from Novo Airão, Central Amazon). The failure in the present study to detect diagnostic loci, which could be very useful for differentiating S. aequifasciatus from S. discus species, and polymorphic loci, which could also be applied for possible identification and delimitation of their stocks, does not rule out the possibility of there existing in other isoenzyme gene loci to be analyzed in the future.

The monotony of transferrin and esterase electrophoretic patterns in pirarucu, Arapaima gigas (Schinz, 1822) from Santa Cruz Lake, Tefé River, Amazonas, Brazil

Starch gel electrophoresis was used for examining the transferrin gene locus (Tf) and two esterase gene loci (Est-1 and Est-D1) of a pirarucu (Arapaima gigas) population sample collected from Santa Cruz Lake, Tefé River, Amazonas, Brazil. The Tf locus was tentatively classified as being polymorphic, showing two double-banded patterns (Tf(12) and Tf(22)) of the three theoretically expected ones (Tf(11), Tf(12) and Tf(22)), presumably controlled by two co-dominant alleles, Tf(1) and Tf(2). The monotony detected in pirarucu Tf locus genotypes showing a very high proportion of the double-banded heterozygote pattern Tf(12) (95% of the sampled individuals) may indicate the possibility of their having come from representatives of the same brood begotten by a pair of fish, where a single-banded Tf(11) homozygote pattern male would have crossed with a single-banded Tf(22) homozygote pattern female, or vice versa. One zone of electrophoretic activity was detected in esterase, presumably controlled by a monomorphic Est-1 locus with the fixed allele Est-1(1) where all individuals showed the single-banded Est-1(11) homozygote pattern. Esterase-D also displayed one zone of electrophoretic activity, presumably controlled by a monomorphic Est-D1 locus with a fixed allele Est-D1(1) where all individuals revealed the single-banded Est-D1(11) genotype pattern. The monotony comprised by single-banded genotype patterns in both esterase systems tested may also indicate the possibility of the individuals from the sample examined having come from representatives of the same brood begotten by a pair of fish with both the male and female having the same genotypes.

Angiogenesis and inflammation in skeletal muscle in response to ascites tumor in mice

This study addresses the interaction between Ehrlich ascites tumor and skeletal abdominal muscle, presenting quantitative analysis of ascites-induced angiogenesis and inflammation in this tissue of mice bearing-tumor. Time-dependent changes in the muscle (cellular activity, angiogenesis, inflammation and cytokines production) were assessed by morphometric, functional, and biochemical parameters at days 1, 4 and 8 after i.p. inoculation of Ehrlich tumor cells (2.5 x 10(7)). The number of cells stained with AgNOR technique (argyrophilic nucleolar organizer region) in the muscle, together with MTS assay used as markers of cellular activity increased progressively in parallel with the out flow rate of sodium fluorescein (blood flow index), hemoglobin content (vascular index) and VEGF production. Likewise, the inflammatory process in the muscle, as assessed by myeloperoxidase (MPO) and n-acethylglucosaminidase (NAG) activities and the levels of the chemokines, keratinocyte-derived chemokine (CXC1-3/KC) and macrophage-chemoattractant protein (CCL2/MCP-1) increased with tumor development. The combination of techniques used to describe angiogenesis and inflammation in a muscle model system has proved to be suited for quantitative measurements of microvascular changes and cellular infiltration occurring in the abdominal muscle wall of ascites-bearing mice. This study holds potential for investigating events and mechanisms associated with skeletal muscle response to neoplasic stimulus.

Impaired inflammatory angiogenesis, but not leukocyte influx, in mice lacking TNFR1

The majority of biological responses classically attributed to tumor necrosis factor alpha (TNF-alpha) is mediated by p55 receptor (TNFR1). Here, we aimed to clarify the biological role of TNFR1-mediated signals in an in vivo inflammatory angiogenesis model. Polyester-polyurethane sponges, used as a framework for tissue growth, were implanted in C57Bl/6 mice. These implants were collected at days 1, 7, and 14 post-implant for enzyme-linked immunosorbent assay or at days 7 and 14 for hemoglobin, myeloperoxidase, and N-acetylglucosaminidase measurements, used as indexes for angiogenesis, neutrophil, and macrophage accumulation, respectively. In TNFR1-deficient C57Bl/6 mice, there was a significant decrease in sponge vascularization but not in late inflammatory cell influx. It is interesting that levels of vascular endothelial growth factor were significantly lower in TNFR1-deficient than in wild-type mice at days 1 and 7. Levels of angiogenic chemokines, CC chemokine ligand 2/murine homologue of monocyte chemoattractant protein-1 and CXC chemokine ligand 1-3/keratinocyte-derived chemokine, were significantly lower in TNFR1-deficient mice at days 1 and 7 after implantation, respectively. These observations suggest that TNFR1-mediated signals have a critical role in sponge-induced angiogenesis, possibly by influencing the effector state of inflammatory cells and hence, modulating the angiogenic molecular network.

Production and in vivo effects of chemokines CXCL1-3/KC and CCL2/JE in a model of inflammatory angiogenesis in mice

OBJECTIVE

Using the murine sponge model, we investigated the temporal relationship between angiogenesis, leukocyte accumulation and endogenous generation of the pro-inflammatory chemokines CXCL1-3/KC and CCL2/JE. Furthermore, the effects of exogenous administration of these chemokines were studied.

METHODS

Angiogenesis in the implants was assessed by measuring the hemoglobin content (vascular index) and leukocyte accumulation quantified by evaluating MPO and NAG enzyme activities.

RESULTS

A progressive increase in hemoglobin content and in enzymatic activities was observed during the whole period. The levels of CXCL1-3/KC and CCL2/JE in the implants peaked at days 7 and 1, respectively. Exogenous administration of CXCL1-3/KC (100 ng/day intra-implant) applied at days 1-3 resulted in increased neovascularization and macrophage accumulation. Intra-implant injections of CCL2/JE (100 ng/day) also resulted in increased angiogenesis and macrophage accumulation.

CONCLUSIONS

These results demonstrated that the chemokines, CXCL1-3/KC and CCL2/JE, are generated within the sponge compartment and that neovascularization and inflammatory cells influx can be modulated by exogenous administration of the chemokines.

Efeitos dos cloretos de potássio e de amônia sobre o desempenho e deposição de gordura na carcaça de frangos de corte criados no verão

Foram utilizados 240 frangos machos, Hubbard, com peso médio inicial de 1204g, em DIC, com os tratamentos em esquema fatorial 2 x 3 x 2, sendo 2 níveis de KCl (0,0% e 1,2%) x 3 níveis de NH4Cl (0,0%; 0,2% e 0,4%) x 2 níveis de energia (3000 e 3200 kcal EM/kg de ração), com 4 repetições de 5 aves por parcela. Os parâmetros avaliados foram: peso médio (PM), consumo de ração (CR), ganho de peso (GP), conversão alimentar (CA), rendimento de carcaça (RC) e gordura abdominal (GA). Os dados foram analisados pelo programa estatístico Statistical Analyses System (SAS, 1996). As temperaturas máxima e mínima foram de 32,7° e 22,8°C, e o índice de temperatura do globo negro e umidade (ITGU) observado às 9:00 e 15:00 horas foi de 76 e 83, respectivamente. A análise de variância revelou interação (p<0,05) apenas entre o KCl e o nível energético da ração sobre o CR. Não se verificou efeito (p>0,05) dos fatores estudados sobre o PM e GP. Para a CA houve efeito (p<0,05) do NH4Cl e do nível energético da ração. Para o rendimento de carcaça, não se observou efeito (p>0,05) dos fatores estudados. Os frangos que receberam ração suplementada com 1,2% KCl apresentaram menor teor de gordura abdominal (p<0,05) em relação aos que não receberam a suplementação (1,16% vs 1,40%, respectivamente) e o nível energético alto elevou significativamente (p<0,01) a gordura abdominal em relação ao nível baixo (1,42% vs 1,14%, respectivamente). Com os resultados obtidos, concluiu-se que a elevação do nível energético da ração melhorou a conversão alimentar e aumentou a gordura abdominal; o KCl não afetou o desempenho, mas reduziu (p<0,05) a gordura abdominal independente do nível de energia da dieta; e a suplementação com 0,4% de NH4Cl piorou a conversão alimentar de frangos de corte criados no verão.

Aminoguanidine prevents impaired healing and deficient angiogenesis in diabetic rats

The diabetic organism is unable to produce normal amount of granulation tissue which results in delayed wound healing, a significant clinical problem. In the present study, the effect of oral administration of aminoguanidine (AG), in the diabetes-induced inhibition of angiogenesis and granulation tissue formation was tested. Subcutaneous implantation of sponge discs in nondiabetic rats induced a wound repair response as determined by the amount of hemoglobin (vascular index) and granulation tissue formation (morphometric analysis) of the implants. In the streptozotocin-induced diabetic rats the predominant response indicative of healing was inhibitory. Aminoguanidine was effective in preventing in 50% the diabetes-induced inhibition of fibrovascular tissue growth in the implants, as indicated by the values of hemoglobin content and vascular growth areas of the implants. These results indicate that AG holds potential therapeutic value in the management of healing impairment of the diabetic condition.

Glucose-induced inhibition of angiogenesis in the rat sponge granuloma is prevented by aminoguanidine

Angiogenesis and granulation tissue formation that occur following subcutaneous implantation of sponge implants in nondiabetic rats were inhibited by topical administration of D-glucose (22 mM). The healing impairment induced by glucose was analogous to healing failures associated with diabetes. Angiogenesis has been determined by measuring hemoglobin content in the implants, correlated with histological evidence of cellular infiltration and granulation tissue formation. The amount of hemoglobin detected in the glucose-treated implants was significantly lower (0.06+/-0.005 g/dl) than the amount in the controls that received glucose 5 mM (0.12+/-0.012 g/dl), saline (0.10+/-0.006 g/dl) or mannitol (0.086+/-0.007 g/dl). Parallel histological studies corroborated the biochemical findings. Daily intraperitoneal injection of aminoguanidine (AG, 50 mg/kg) prevented glucose-induced inhibition of neovascularization and cellular infiltration in the sponge granuloma. Our results show the direct inhibitory effect of high glucose in the development of granulation tissue and indicate that it may be associated with nonenzymatic glycation of key components of the healing process in the rat sponge granuloma.

Sponge-induced angiogenesis in mice and the pharmacological reactivity of the neovasculature quantitated by a fluorimetric method

Sponge-induced angiogenesis in mice and pharmacological reactivity of the neovasculature have been determined by a fluorimetric method. Pharmacokinetic studies following subcutaneous, intradermal, and intraimplant administration of sodium fluorescein resulted in a biphasic curve from which estimation of t1/2 for absorption and elimination of the dye were possible. Following topical injection of the dye at days 1, 4, 7, 10, and 14 postimplantation, measurement of fluorchrome generated emission in the systemic circulation reflected the development of blood flow in and around the implants and the interaction of the angiogenic site with the systemic circulation. The t1/2 values for the fluorescence peak in the bloodstream decreased steadily from an initial value of 6.41 +/- 0.28 min (avascular implant) to 2.78 +/- 0.23 min in fully vascularized implants (day 14). The reactivity of the neovasculature to ET-1 was dose-dependent and similar to the skin vasculature. By contrast, no reactivity to histamine was detected in the implant blood vessels, whereas it was present in the skin. These results show that the pharmacological response of the neovasculature differs from the response of mature blood vessels. The angiogenic stimulus (bFGF, 300 ng daily) decreased t1/2 for the fluorescence peak, whereas dexamethasone (1 mg/kg) increased it. Parallel histological studies corroborated the functional findings. These observations indicate the suitability of this assay to study angiogenesis, functional and pharmacological characterization of the neovasculature, and the interaction of the angiogenic site with the systemic circulation.

Bullet embolism into the cardiovascular system

Two clinical case reports of bullet embolism into the cardiovascular system are reported. The patient in the first case sustained a gunshot wound at the right clavicular area with embolism resulting in the right ventricle. In the second case, the patient received a projectile wound to the anterior right shoulder with eventual bullet embolism in the left iliac artery. In both cases, the bullets were removed successfully. Surgical intervention with the aid of extracorporeal circulation is recommended for similar cases.

The effects of acute and chronic ethanol administration on canine bile secretion

In 9 conscious dogs (4 of whom were alcohol-fed for 24 months with 50% intragastric ethanol), provided with gastric and duodenal fistulae (Thomas cannula), the effects were studied of an acute iv ethanol infusion (1.3 g/kg) on hepatic bile secretory plateau levels after emptying of the gallbladder was induced by a continuous perfusion of secretin (0.5 CU/kg/hr) plus CCK-PZ (8 Crick-Harper-Raper U/kg/hr) and sodium taurocholate (0.62 mumol/kg/min). Acute iv ethanol infusion in nonalcoholic dogs reduced hepatic bile flow rate (29%), bile salt concentration (55%) and output (67%). In alcohol-fed dogs, acute iv ethanol reduced only the rate of flow (25%). Hepatic bile salt concentration and output plateau values were significantly higher in the alcohol-fed than in the nonalcoholic dogs. There were no significant differences between the two groups of dogs in the rate of evacuation, bile salt output, or lipid composition of gall bladder bile following a single iv injection of CCK-PZ.

Action of intragastric ethanol on the pancreatic secretion of conscious rats

A surgical procedure has been disigned which permits injection in the stomach and the duodenum by separate catheters, collection of the pancreatic juice during the experiments, recirculation of the pancreatic juice into the duodenum between experiments, and a normal circulation of bile in rats. Experiments were performed in conscious rats given either 20% ethanol or water. In rats submitted to daily ethanol consumption for 13 months, the intragastric injection of 2 g/kg 20% ethanol considerably increased the pancreatic secretion of protein and, to a lesser extent, of water. In control non-alcoholic rats, a short period of increased secretion is followed by a major inhibition of pancreatic secretion, this reverse reaction to ethanol of pancreatic secretion according to whether or not rats are adapted to regular ethanol consumption is similar to what has been previously observed in dog. In chronic alcoholic rats, the release of secretin is probably not very different from controls.