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This article was published in Volume 62, issue 6 of publishing year 2022, with a mistake in Table II. The correct Table II is the one included in this erratum.

Asimakidis, ND, Dalamitros, AA, Ribeiro, J, Lola, AC, and Manou, V. Μaturation stage does not affect change of direction asymmetries in young soccer players. J Strength Cond Res 36(12): 3440-3445, 2022-This study examined whether the stage of biological maturation can affect interlimb asymmetries during a change of direction (COD) test. Seventy-six young soccer players were divided into 2 different groups according to their peak height velocity stage (PHV): pre-PHV (n = 45, age = 11.8 ± 1.2 years, height = 149.8 ± 9.3 cm, body mass = 43.9 ± 11.2 kg) and post-PHV (n = 31, age = 14.4 ± 0.9 years, height = 170.0 ± 4.9 cm, body mass = 61.5 ± 8.9 kg). Subjects performed a 505 test to measure the completion time in both directions and a 20-m maximum sprint test. Change of direction deficit (CODD) was used as a measure for isolating COD ability. An independent sample t-test detected no significant differences between the asymmetry index values for the 505 test completion time when the pre-PHV group and the post-PHV group were compared (-3.49 ± 2.49% vs. -3.45 ± 2.47%, effect size [ES] = 0.02, p = 0.923). Similarly, the CODD asymmetry index indicated no differences between the 2 groups (-8.21 ± 5.95% vs. -7.37 ± 5.12%, ES = 0.15, p = 0.457). A paired sample t-test revealed that the values of the CODD asymmetry index were larger than those of the 505 asymmetry index (-7.88 ± 5.61% vs. -3.49 ± 2.46%, ES = 1.09, p0.001). According to these results, maturational status has no influence on the interlimb asymmetries of COD ability. Furthermore, subjects showed greater asymmetry values in CODD compared with the 505 test completion time, reinforcing that the evaluation of COD asymmetries should be based on CODD. As interlimb asymmetries are not altered during the maturation process, practitioners should address abnormal COD asymmetries early on during athletes' development processes.

International audience; BACKGROUND: Young swimmers are rarely involved in training control, leading to inadequate volume and prescription of training intensities. This study aimed to examine the effect of prescribing and monitoring training intensities around critical velocity (CV) on 400 m frontcrawl performance during an 8-weeks period. METHODS: Twenty young male swimmers (13.4±1.0 years) were randomly assigned into two groups. The experimental group (EG) used training monitoring based on intensities around CV (95, 100, 105 and 110% of CV), while for the control group (CG) different heart-rate (HR) zones (EN1+, EN2, EN2+ and EN3) were used as an intensity criterion. The training volume was the same for both EG and CG. A maximal 400 m front-crawl test was performed before and after the 8-week period to determine CV intensities and to assess alternations in performance. The rate of perceived exertion (RPE) and HR values were also evaluated. RESULTS: Significant main effects of time were observed for T400, CV, HR and RPE. A significant group x time interaction was found for T400 (p=0.035, effect size=1.07, moderate). Results revealed significant pre-to-post improvements for both EG (from 328.46±26.25 to 305.88±20.09) and CG (from 329.07±25.24 to 314.75±19.87). A significant group x time interaction was also found for CV (p=0.005, effect size=1.51, large). Results revealed significant pre-to-post improvements for both EG (from 1.126±0.08 to 1.207±0.07) and CG (from 1.124±0.08 to 1.173±0.07). CONCLUSIONS: Both training methods induced significant improvements in 400 m front-crawl performance with a greater degree for the training prescription and monitoring using CV intensities.

This study analysed the effects of two different periodization strategies on physiological parameters at various exercise intensities in competitive swimmers. Seventeen athletes of both sexes were divided to two groups, the traditional periodization (TPG, n = 7) and the reverse periodization group (RPG, n = 10). Each group followed a 10-week training period based on the two different periodization strategies. Before and after training, swimming velocity (SV), energy expenditure (EE), energy cost (EC) and percentage of aerobic (%Aer) and anaerobic (%An) energy contribution to the swimming intensities corresponding to the aerobic threshold (AerT), the anaerobic threshold (AnT) and the velocity at maximal oxygen uptake (vVO2max) were measured. Both groups increased the %An at the AerT and AnT intensity (P ≤ .05). In contrast, at the AnT intensity, EE and EC were only increased in TPG. Complementary, %Aer, %An, EE and EC at vVO2max did not alter in both groups (P > .05); no changes were observed in SV in TPG and RPG at all three intensities. These results indicate that both periodization schemes confer almost analogous adaptations in specific physiological parameters in competitive swimmers. However, given the large difference in the total training volume between the two groups, it is suggested that the implementation of the reverse periodization model is an effective and time-efficient strategy to improve performance mainly for swimming events where the AnT is an important performance indicator. Sin financiación 2.576 JCR (2017) Q2, 22/81 Sport Sciences 1.122 SJR (2017) Q1, 480/2878 Medicine (miscellaneous), 44/285 Orthopedics and Sports Medicine, 24/201 Physical Therapy, Sports Therapy and Rehabilitation; Q2, 34/127 Sports Science No data IDR 2017 UEM

Dalamitros, AA, Zafeiridis, AS, Toubekis, AG, Tsalis, GA, Pelarigo, JG, Manou, V, and Kellis, S. Effects of short-interval and long-interval swimming protocols on performance, aerobic adaptations, and technical parameters: A training study. J Strength Cond Res 30(10): 2871-2879, 2016-This study compared 2-interval swimming training programs of different work interval durations, matched for total distance and exercise intensity, on swimming performance, aerobic adaptations, and technical parameters. Twenty-four former swimmers were equally divided to short-interval training group (INT50, 12-16 × 50 m with 15 seconds rest), long-interval training group (INT100, 6-8 × 100 m with 30 seconds rest), and a control group (CON). The 2 experimental groups followed the specified swimming training program for 8 weeks. Before and after training, swimming performance, technical parameters, and indices of aerobic adaptations were assessed. ΙΝΤ50 and ΙΝΤ100 improved swimming performance in 100 and 400-m tests and the maximal aerobic speed (p ≤ 0.05); the performance in the 50-m swim did not change. Posttraining V[Combining Dot Above]O2max values were higher compared with pretraining values in both training groups (p ≤ 0.05), whereas peak aerobic power output increased only in INT100 (p ≤ 0.05). The 1-minute heart rate and blood lactate recovery values decreased after training in both groups (p < 0.01). Stroke length increased in 100 and 400-m swimming tests after training in both groups (p ≤ 0.05); no changes were observed in stroke rate after training. Comparisons between groups on posttraining mean values, after adjusting for pretraining values, revealed no significant differences between ΙΝΤ50 and ΙΝΤ100 for all variables; however, all measures were improved vs. the respective values in the CON (p < 0.001-0.05). In conclusion, when matched for distance and exercise intensity, the short-interval (50 m) and long-interval (100 m) protocols confer analogous improvements in swimming performance, in stroke cycle parameters, and in indices of aerobic adaptations after 8 weeks of training.

Purpose The purpose of the study was to examine the in-season variations in aerobic power, anaerobic power, and vertical jumping ability in young elite handball players in a laboratory setting. Methods The study involved 13 athletes (age: 19.9 ± 0.7 years, body mass: 90.0 ± 12.1 kg, height: 186.3 ± 6.3 cm, body fat percentage: 13.7 ± 4.8%), all members of the young national handball team. Maximal oxygen uptake (VO2max), Wingate Anaerobic Test (WAnT) performance (peak power [PP], mean power [MP], fatigue index [FI]), and vertical jumping ability(countermovement jump [CMJ]) were assessed on 3 occasions during the competitive period (beginning [T1], middle [T2], end [T3]). Results Only slight and not significant changes were observed throughout the tested period for VO2max (T1 = 52.04 ± 4.30; T2 = 49.31 ± 3.96; T3 = 51.68 ± 5.38 ml ∙ kg–1; T1 to T3: –0.24 ± 5.83%, p > 0.05) and CMJ values (T1 = 46.99 ± 7.98; T2 = 46.57 ± 5.87; T3 = 48.15 ± 6.58 cm; T1 to T3: –3.26 ± 6.88%, p > 0.05). Similarly, all parameters evaluated during the WAnT showed small variations (PP: T1 to T3: 1.11 ± 5.67%; MP: T1 to T3: –0.04 ± 4.34%; FI: T1 to T3: 3.43 ± 9.20%; p > 0.05). Conclusions The indices of aerobic power, anaerobic power, and vertical jumping ability remained relatively constant among the tested group of young elite athletes throughout the handball competitive period. Sin financiación No data JCR 2019 0.787 SJR (2019) Q2, 45/140 Biophysics No data IDR 2019 UEM

Previous studies demonstrated significant increases in the shoulder internal rotators’ peak torque values and unilateral muscular imbalances of the shoulder rotators after a competitive swim period. However, there are no similar data concerning the knee muscles. The purpose of the current study was to examine the effects of a six-month training period on knee flexor and extensor peak torque values, examine a possible bilateral strength deficit and evaluate the unilateral strength balance in competitive swimmers. Eleven male adolescent swimmers (age: 14.82 ± 0.45 years) were tested for concentric knee extension and flexion peak torque (60°/s) with an isokinetic dynamometer, before and after a regular combined swim and dry-land strength training period. A trend towards greater improvements in the knee extensor compared to flexor muscles peak torque was observed. Furthermore, the bilateral strength deficit remained almost unchanged, whereas unilateral strength imbalance was increased for both limbs. However, all results were nonsignificant (p > 0.05). According to the data presented, a six-month regular combined swim and dry-land strength training period caused non-significant alterations for all the parameters evaluated during isokinetic testing. This study highlights the fact that competitive adolescent swimmers demonstrated unilateral knee strength imbalances throughout a long period of their yearly training macrocycle.

Purpose. The purpose of the study was to compare the effectiveness of 2 different dry-land active warm-up protocols on 50-m front-crawl swimming performance, biomechanical variables (stroke rate, stroke length, and stroke index), rate of perceived exertion, and exercise heart rate in swimmers of both genders. Methods. The total of 10 male and 9 female national-level swimmers completed a standardized 1000-m in-water warm-up protocol followed by a 30-min transition phase and a 50-m front-crawl time-trial. During this 30-min period, each swimmer executed, on different occasions, a protocol consisting of either a dynamic stretching routine (stretch) or a power exercise circuit (power) of equal duration (~ 5 min) in a randomized sequence. A control condition (control) including a passive recovery strategy after the in-water warm-up protocol was also analyzed. Results. An improvement in 50-m time-trial performance was demonstrated in male swimmers after executing the power protocol (p = 0.034), while in female swimmers a trend towards faster performance times was revealed after the stretch protocol (p = 0.064). Stroke index was improved after the stretch routine only in female swimmers (p = 0.010). Stroke rate, stroke length, rate of perceived exertion, and exercise heart rate showed no differences among all the 3 conditions in either gender (p > 0.05). Conclusions. Male and female swimmers respond differently to a power or a dynamic stretching protocol. In addition, the variation in responses to different warm-up conditions highlights the importance of individualizing the dry-land warm-up procedure to promote maximum performance during 50-m front-crawl swimming events. Key words: warm-up strategies, sprint performance, national-level swimmers Sin financiación No data JCR 2018 0.197 SJR (2018) Q3, 138/191 Physical Therapy, Sports Therapy and Rehabilitation; Q4, 106/133 Biophysics, 422/530 Public Health, Environmental and Occupational Health No data IDR 2018 UEM

This study compared the effect of two training strategies differing on the weekly intensity distribution on physiological parameters and running performance in moderately trained endurance athletes. METHODS: Thirty male athletes were equally divided into three groups, one following an increasing weekly aerobic intensity distribution (EXP1), one with constant weekly aerobic intensitydistribution (EXP2) and a control one, following a freely chosen program (CON). Before the training intervention, athletes performed a maximal exercise treadmill test to quantify the different zones allowing training to be controlled, based on blood lactate concentration values (BLa), over a 4- week period. Changes in exercise heart rate (HR), running velocity and rate of perceived exertion at three exercise intensities corresponding to 2.5, 4 and 8 mmol·l-1 of BLa were analyzed at three testing conditions: before (pre), after two (mid) and four weeks (post). RESULTS: A significant increase (p ≤ 0.05) in running velocity at the intensity of 8 mmol·l-1 in EXP1 group was revealed at mid (5.5%) and post condition (11.5%), while EXP2 group showed a significant decrease in exercise HR at 4 mmol·l-1 between pre (6.7%) and post condition (9.0%) (p ≤ 0.05). The rest of the examined variables showed only trivial changes in both experimental groups at all testing conditions (p > 0.05). In addition, no changes were observed in CON group in any of the variables tested. CONCLUSION: These results demonstrate that depending on the training goal, different intensity variation strategies should be followed to induce the desired adaptations. Sin financiación 1.302 JCR (2018) Q4, 66/83 Sport Sciences 0.537 SJR (2018) Q2, 124/289 Orthopedics and Sports Medicine, 79/209 Physical Therapy, Sports Therapy and Rehabilitation; Q3, 79/125 Sports Science No data IDR 2018 UEM

This study examines the relationship between speed reserve (SRes), critical swimming speed (CSS), and anaerobic distance capacity (ADC) and their efficacy in determining training adaptations. Swimmers with previous competitive experience participated in an 8-week aerobic training program (experimental group: E; n = 15, age: 22.29 ± 0.95 years) and a control group refrained from training during the same period (C; n = 6, age: 22.25 ± 2.22 years). Speed reserve was determined before and after training from the speed difference between the 50 and 400 m maximum tests. Both CSS and ADC were calculated using 2 different combinations of distances (50 and 400 m: CSS2/ADC2; 50, 100, and 400 m: CSS3/ADC3) by applying the distance-time linear regression model. CSS2 and CSS3 of the E group showed a negative correlation, whereas ADC2 and ADC3 showed a positive correlation, with SRes before and after the training period (r ≥ -0.66, r ≥ 0.88, p ≤ 0.05). CSS2 and CSS3 increased by 5.5 ± 3.2 and 6.0 ± 3.2%, whereas ADC2, ADC3, and SRes decreased by 12.0 ± 9.4, 9.0 ± 11.2, and 8.1 ± 8.4% with the training program (p ≤ 0.05). These findings suggest that SRes, as calculated from distances of 50 and 400 m, shows strong relationships with CSS and ADC and may be used as an indicator of training-induced changes. This information is expected to facilitate training control and evaluation in a day-to-day basis.

Dalamitros, A.A., Manou, V., & Pelarigo, J.G. (2014). Laboratory-based tests for swimmers: methodology, reliability, considerations and relationship with front-crawl performance. J. Hum. Sport Exerc., 9(1), pp.172187. Monitoring training process in swimming is essential for providing valuable information for both coaches and athletes. Among a large variety of laboratory-based tests used for the quantification of swimmers abilities and evaluation of fitness status, the most representative and easy to apply ones are chosen to be presented in this review. Furthermore, these tests reliability, methodology, referred considerations and relationship with front-crawl swimming performance are reported. Based on the previous mentioned criteria, the assessment of aerobic, anaerobic power and muscular strength, are analyzed. From the data examined, it is concluded that despite their reliability and efficacy in determining adaptations after a training period, as well as, detecting differences between athletes’ training status, laboratory-based tests assessing aerobic, anaerobic power and muscular strength for swimmers does not

This study examined the effects of age on recovery of peak torque of knee extensors (PTEX) and flexors (PTFL), and total work (TW) during high-intensity intermittent 30-s (HI30) and 60-s (HI60) exercise in boys (N=19; age, 11.4+/-0.5 yr), teens (N=17; age, 14.7+/-0.4 yr), and men (N=18; age, 24.1+/-2.0 yr).Each age group's subjects were subdivided to participate in an HI30 or an HI60 protocol. The HI30 involved 4x18 maximal knee extensions and flexions (1-min rest between sets), and the HI60 comprised of 2x34 reps (2-min rest). PTEX (N.m.kg), PTFL (N.m.kg), and TW (J.kg) were recorded at each set. The percent recovery of PTEX, PTFL, and TW was calculated as percent of the value achieved in the first set.In HI60, the percent recovery for PTEX, PTFL, and TW after the first set was higher in boys compared with teens and men (P0.01). In HI30, the percent recovery for PTEX, PTFL, and TW was higher in boys compared with men in all sets (P0.01), and in teens compared with men in the last two sets (P0.05). The percent recovery of PTFL and TW was higher in boys compared with teens in the last two sets (P0.05). Lactate increase was most pronounced in men, less pronounced in teens, and least pronounced in boys (P0.01). Heart rate recovered faster in boys compared with teens and men in both protocols (P0.05).The recovery was faster in boys than in teens and men during HI30 and HI60, as evident by the greater percent recovery in boys for a given time. Furthermore, it appears that the rate of recovery during HI30 and HI60 anaerobic exercise is maturity dependent.