Maturation Stage Does Not Affect Change of Direction Asymmetries in Young Soccer Players.

ABSTRACT: 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, p < 0.001). 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.

Effect of the COVID-19 Confinement Period on Selected Neuromuscular Performance Indicators in Young Male Soccer Players: Can the Maturation Process Counter the Negative Effect of Detraining?

The COVID-19 outbreak has led to an unprecedented long-term cessation in athletes' training routines. This study examined the effect of a 32-week detraining period, caused by the COVID-19 pandemic lockdown, on selected neuromuscular performance indicators in 29 young male soccer players, assessed close to their adolescent growth spurt (age = 13.0 ± 0.8 years). Change of direction ability of both lower limbs (COD), linear sprint times (10 and 20 m), and vertical jump height (CMJ) was evaluated twice, once before the first national lockdown, and one week after the return to training activities. Paired-sample t-tests detected significant improvements in all three testing variables (COD: 2.82 ± 0.23 vs. 2.66 ± 0.22 s, p ≤ 0.005, 0.001, effect size [ES] = 0.91 to 1.05 for the right and left limb, respectively; 10 m: 2.12 ± 0.16 vs. 1.96 ± 0.15 s, p ≤ 0.001, effect size [ES] = 1.67, 20 m: 3.56 ± 0.3 vs. 3.42 ± 0.27 s, p ≤ 0.001, effect size [ES] = 1.02 and CMJ: 23.3 ± 7.5 vs. 24.5 ± 7.6 cm, p = 0.033, ES = 0.42). These results indicate that maturation-related adaptations can lead to enhanced change of direction, linear sprint, and vertical jump performance, even in the absence of exposure to any level of exercise. Soccer coaches and practitioners working with youth athletes should consider the stage of maturation when planning and implementing training programs aiming to enhance neuromuscular performance.

The effects of free weights and isoinertial resistance during semisquatting exercise on amateur soccer players' physical performance indicators: a randomized controlled study.

BACKGROUND: The aim of this study was to compare the effects of two lower extremity strengthening programs using isoinertial resistance or free weights on amateur soccer players' physical performance indicators. METHODS: Thirty-five amateur soccer players (average age 22.6±5.1 years) were randomly assigned to isoinertial group (N.=11) or free-weight group (N.=11), or control group (N.=13). The groups performed two training sessions per week for six weeks. Before and after the strengthening implementation, physical performance indicators were evaluated, including the isokinetic knee extensors and flexors' strength, power, speed, and agility. The significance level was set at P<0.05. RESULTS: The isoinertial training resistance led to an increase in the hamstrings' eccentric strength at 60°/s and 150°/s (P<0.05) compared to the free-weight resistance (P>0.05) and the controls (P>0.05). No other significant adaptations were observed in the other isokinetic strength, power, speed (10-m, P=0.052) and agility measurements (Illinois Agility Test, P=0.059). In ratio (knee flexors/knee extensors) the only differences observed were at 150°/s for isoinertial group (P<0.05). CONCLUSIONS: Isoinertial resistance training during semisquatting can enhance the hamstrings' eccentric performance and the soccer players' speed and agility compared to the classic free-weight training program, which should consider when designing strength and injury prevention programs.

A Novel Customized 3D Printed Arm Stand Improving Skin Preparation Efficiency in Hand Surgery.

Patient preparation for hand surgery often necessitates skin preparation via the use of an assistant to hold the arm to be operated on in mid-air while disinfectant is applied. This study introduces a three-dimensional printed arm stand that decreases dead time during skin preparation, while also enabling the more efficient use of an assistant. The arm stand devices were customized on the anatomy of the patients and then successfully used on patients having general or regional anesthesia. A practical, reusable, and effective three-dimensional printed arm stand has been developed and applied on both adult and pediatric patients. We have found the bespoke device to be beneficial in terms of reducing theater dead time and overall costs, while increasing the efficiency of an upper limb operating theater list. The rapid prototyping cycle afforded by 3D printing renders this technology a valuable tool for developing medical devices with patient-precise dimensions.

Comparison of the Serum Metabolic Fingerprint of Different Exercise Modes in Men with and without Metabolic Syndrome.

Exercise plays a beneficial role in the treatment of metabolic syndrome (MetS). Metabolomics can provide new insights and facilitate the optimization of exercise prescription. This study aimed to investigate whether the response of the human serum metabolic fingerprint to exercise depends on exercise mode or the presence of MetS. Twenty-three sedentary men (nine with MetS and fourteen healthy) completed four trials: Resting, high-intensity interval exercise (HIIE), continuous moderate-intensity exercise (CME), and resistance exercise (RE). Blood samples were collected pre-exercise, immediately after exercise, and 1 h post-exercise for targeted metabolomic analysis in serum by liquid chromatography-mass spectrometry. Time exerted the strongest differentiating effect, followed by exercise mode. The largest changes from baseline were found in the immediate post-exercise samples. RE caused the strongest responses overall, followed by HIIE, while CME had minimal effect. Unlike previous results in urine, no valid model could separate the two groups in serum. Exercise exerted a beneficial effect on prominent serum biomarkers of metabolic risks, such as branched-chain amino acids, alanine, acetylcarnitine, choline, and betaine. These findings contribute to the ongoing research efforts to map the molecular responses to exercise and to optimize exercise guidelines for individuals at cardiometabolic risk.

Traditional Dance Improves the Physical Fitness and Well-Being of the Elderly.

Regular physical activity is considered one of the most important factors for lifestyle, for maintaining good health in older ages and increasing life expectancy. Dance is considered an activity that involves coordinating movements with music, as well as brain activation because it is constantly necessary to learn and remember new steps. Dance as a musical-kinetics skill, requires the coordination of body movements with rhythmic stimuli, developing the adaptability of the movement. One-hundred-thirty (130) elderly people aged 60 years and over (mean age 67 years old) with an average of 8 years of education, attended Greek traditional dance sessions for 32 weeks. The frequency was 2 times per week, for 75 min per session. Dances were selected from all over Greece with moderate intensity initially. During the program, they had the opportunity to try with greater intensity dances. At the beginning and after the end of intervention all the participants were evaluated by the Fullerton Senior Fitness Test for their physical fitness, the Single Leg Balance and the Handgrip Strength Test. The results showed a significant improvement in their physical fitness (Chair Stand: T = -5.459, p < 0.001; Arm Curl: T = -5.750, p < 0.001; Back Scratch: T = -4.648, p < 0.001; Sit and Reach: T = -4.759, p < 0.001; 2 min Step: T = -5.567, p < 0.001; Foot Up and Go: T = -8.599, p < 0.001) and at their static balance with eyes open (Balance 1 leg: T = -4.996, p < 0.001) and Handgrip Strength (Handgrip: T = -3.490, p < 0.001). Elderly seem to enjoy dancing as an activity while maintaining their functionality. Probably the elderly in traditional dance cause prosperity in their lives by promoting active aging.

Psychophysiological and performance-related responses of a potentiation activity in swimmers of different competitive levels.

Athletes' competitive level has an effect on several psychophysiological parameters during the execution of sports-related tasks. This study analyzed the acute effect of a potentiation activity (PAP), composed by 5 loaded box jumps, on specific psychological, physiological and performance-related parameters in 22 trained (COM) and untrained (UNT) adult male swimmers. A control condition was also evaluated. Measurements included the Competitive State Anxiety Inventory, rate of perceived exertion, lower limbs muscle oxygenation, exercise heart rate, vertical jumping ability, 3 different split times and total time-trial performance during an all-out 50-m swim test executed using the breaststroke technique. In addition, total swim strokes and the optimal individual response after the potentiation activity were measured. No significant differences among the two testing conditions were found for all psychological, physiological and performance-related parameters (p > .05) with the exception of total performance time in the UNT group after the PAP condition (41.5 ±â€¯5.3 vs. 41.9 ±â€¯5.5 s; p = .023; ES = 0.6). As expected, the COM group showed enhanced swimming performance during all split times and total time, compared to the UNT group. These results suggest that (i) independently of the training level, psychological responses during sports-related tasks are probably not evident under non-competitive situations and, (ii) competitive level athletes may need more challenging activation stimulus, compared to their less competitive counterparts, to induce the desirable adaptations on the subsequent main activity.

Effects of a Modified Ballet Class on Strength and Jumping Ability in College Ballet Dancers.

The ability to jump high with precision is an important component of the ballet dancer's technique. The aim of this study was to evaluate the effect of a modified ballet class on strength and jumping ability in high level female dancers. Seventeen female ballet students were divided into two groups, experimental and control, and tested before and after an 8-week, 2 times/week intervention for peak torque of knee extensors and flexors at 60°and 180°, and jumping ability (squat jump, countermovement jump, countermovement with arm swing jump, sauté in first position, and sauté in first position with port de bras). Statistical analysis was performed using Analysis of Variance (Anova 2x2) with repeated measure of factor time (pre and post). T-test with Bonferroni adjustment was used to assess any differences between groups. The experimental group showed improvement in height (7.7%), takeoff velocity (4.0%), and power (5.1%) of the squat jump. In addition, increases were revealed in peak (60°, 11.9%; 180°, 7.8%) and relative peak torque (60°, 13.2%; 180°, 9.2%) of the right knee flexors. Moreover, enhancements of the knee flexor-extensor strength ratio in both angular velocities were found (60°, 10.4%; 180°, 9.7%). These outcomes suggest that the proposed program could help ballet dancers improve the height of their vertical jumps and leg strength.

Effects of Different Exercise Modes on the Urinary Metabolic Fingerprint of Men with and without Metabolic Syndrome.

Exercise is important in the prevention and treatment of the metabolic syndrome (MetS), a cluster of risk factors that raises morbidity. Metabolomics can facilitate the optimization of exercise prescription. This study aimed to investigate whether the response of the human urinary metabolic fingerprint to exercise depends on the presence of MetS or exercise mode. Twenty-three sedentary men (MetS, n = 9, and Healthy, n = 14) completed four trials: resting, high-intensity interval exercise (HIIE), continuous moderate-intensity exercise (CME), and resistance exercise (RE). Urine samples were collected pre-exercise and at 2, 4, and 24 h for targeted analysis by liquid chromatography-mass spectrometry. Time exerted the strongest differentiating effect, followed by exercise mode and health status. The greatest changes were observed in the first post-exercise samples, with a gradual return to baseline at 24 h. RE caused the greatest responses overall, followed by HIIE, while CME had minimal effect. The metabolic fingerprints of the two groups were separated at 2 h, after HIIE and RE; and at 4 h, after HIIE, with evidence of blunted response to exercise in MetS. Our findings show diverse responses of the urinary metabolic fingerprint to different exercise modes in men with and without metabolic syndrome.

Effects of Short-Interval and Long-Interval Swimming Protocols on Performance, Aerobic Adaptations, and Technical Parameters: A Training Study.

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.

Knee Muscles Isokinetic Evaluation after a Six-Month Regular Combined Swim and Dry-Land Strength Training Period in Adolescent Competitive Swimmers.

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 non-significant (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.

Is Speed Reserve Related to Critical Speed and Anaerobic Distance Capacity in Swimming?

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.

Report of an unusual combination of arterial, venous and neural variations in a cadaveric upper limb.

In this study an unusual combination of arterial, venous and neural variations discovered during dissection of cervical, axillary and brachial area of a cadaver is described. Variations are thoroughly described and literature is briefly reviewed. Lateral cord of brachial plexus was not formed; Eight Cervical root divided into anterior and posterior division before uniting with First Thoracic root and Upper Trunk was unusually short. Axillary artery gave origin to a superficial brachial artery and then continued as deep brachial artery. Multiple variations in typical axillary artery branches were present including existence of inferior pectoral artery. Cephalic vein was absent. A variety of interventions, from relative simple as central venous catheter placement to most complicated as brachial plexus injury repair demand thorough knowledge of area's regional anatomy. Familiarity with anatomic variations allows more precise and careful interventions. Research on these variations is valuable for anatomists and embryologists but also for clinicians because it may provide useful information for non - typical cases but also helps in raising a high level of suspicion.

Fatigue resistance during high-intensity intermittent exercise from childhood to adulthood in males and females.

This study examined the maturation pattern of fatigue resistance (FR) from childhood to adulthood in females and males during high-intensity intermittent exercise and compared FR between females and males in childhood and adolescence. Thirty males (boys 11.3 +/- 0.5 years, teen-males 14.7 +/- 0.3 years, men 24.0 +/- 2.1 years) and 30 females (girls 10.9 +/- 0.6 years, teen-females 14.4 +/- 0.7 years, women 25.2 +/- 1.4) participated in this study. They performed high-intensity intermittent exercise (4 x 18 maximal knee flexions and extensions with 1-min rest) on an isokinetic dynamometer at 120 degrees s(-1). Peak torque of flexors (PTFL) and extensors (PTEX), and total work (TW) were measured. FR was calculated as % of PTEX, PTFL, and TW in 4th versus 1st set. FR was greater (P < 0.05) in boys versus teen-males and men, and in teen-males versus men. In females, FR was greater (P < 0.05) in girls versus teen-females and women, but not different between teen-females and women. FR was not different in boys versus girls and in teen-males versus teen-females. FR for PTFL, PTEX, and TW correlated negatively (P < 0.001) with the respective peak values (r = -0.68 to -0.84), and FR for TW with peak lactate (r = -0.58 to -0.69). In addition, age correlated (P < 0.01) with FR for males (r = -0.75) and females (r = -0.55). In conclusion, FR during high-intensity intermittent exercise undergoes a gradual decline from childhood to adulthood in males, while in females the adult profile establishes at mid-puberty (14-15 years). The maturation profile of FR in males and females during development appears to reflect the maturation profiles of peak torque, short-term muscle power, and lactate concentration after exercise.

Recovery during high-intensity intermittent anaerobic exercise in boys, teens, and men.

PURPOSE: 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). METHODS: 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. RESULTS: In HI60, the percent recovery for PTEX, PTFL, and TW after the first set was higher in boys compared with teens and men (P<0.01). In HI30, the percent recovery for PTEX, PTFL, and TW was higher in boys compared with men in all sets (P<0.01), and in teens compared with men in the last two sets (P<0.05). The percent recovery of PTFL and TW was higher in boys compared with teens in the last two sets (P<0.05). Lactate increase was most pronounced in men, less pronounced in teens, and least pronounced in boys (P<0.01). Heart rate recovered faster in boys compared with teens and men in both protocols (P<0.05). CONCLUSIONS: 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.