The Genetic Basis of Decathlon Performance: An Exploratory Study.

ABSTRACT: Remmel, L, Ben-Zaken, S, Meckel, Y, Nemet, D, Eliakim, A, and Jürimäe, J. The genetic basis of decathlon performance: an exploratory study. J Strength Cond Res 37(8): 1660-1666, 2023-Decathlon is a combined track and field competition consisting of 10 different events, most of which are anaerobic-type events. Therefore, it is assumed that an anaerobic genetic predisposition might be prevalent among decathletes. Yet, to the best of our knowledge, the genetic basis of decathlon performance had not been studied. Therefore, the aim of this study was to assess the prevalence genetic polymorphisms associated with power performance (AGT, rs699, Met235Thr T/C), speed (ACTN3, rs1815739 C1747T), aerobic endurance (PPARD, rs2016520 T294C), and lactate clearance (MCT1, rs1049434 A1470T) among decathletes. One hundred thirty-seven male track and field athletes (51 sprinters and jumpers, 59 long distance runners, and 27 decathletes) participated in the study. Genomic DNA was extracted from buccal epithelial cells. Genotypes were determined using the Taqman allelic discrimination assay. Decathletes had a higher prevalence of the ACTN3 RR genotype, which is associated with speed ability, and a lower prevalence of the PPARD CC genotype, which is associated with endurance performance compared with long-distance runners. Decathletes had a higher prevalence of the AGT CC genotype associated with strength performance and a higher prevalence of the MCT1 TT genotype, which is associated with improved lactate transport compared with both sprinters and jumpers and long-distance runners. The results suggest that a favorable genetic polymorphism for strength-related capability might be advantageous for decathletes, whereas a genetic makeup favoring aerobic performance is not necessary.

Common genetic basis of ALS patients and soccer players may contribute to disease risk.

OBJECTIVE: The aim of the present study was to determine the prevalence of the ACSL A/G single nucleotide polymorphism among athletes and patients with amyotrophic lateral sclerosis (ALS). ALS is a progressive neurodegenerative disorder of motor neurons that leads to paralysis and death usually within 3-5 years from onset. Previous epidemiological studies reported a higher risk of ALS among soccer players. The ACSL (long-chain-fatty-acid-CoA ligase 1) gene codes the long-chain fatty-acid-coenzyme A ligase family that plays a key role in lipid biosynthesis and fatty acid oxidation. The ACSL A/G polymorphism is associated with endurance trainability. METHODS: One hundred and seventy-eight ALS patients, 172 athletes (60 soccer players, 112 middle- and long-distance runners), and 111 nonathletic controls participated in the study. Genomic DNA was extracted from blood or buccal cells according to the salting-out procedure. Genotypes were determined using the TaqMan allelic discrimination assay. RESULTS: The prevalence of the ACSL AA genotype was significantly higher among soccer players (35.0%) and ALS patients (39.3%) compared to runners (16.1%) and controls (18.0%). However, ALS GG carriers had a higher mortality rate. CONCLUSION: We postulate that soccer players and ALS patients carry a common genetic predisposition that is related to impaired fatty acid utilization. Moreover, while the A allele might be associated with a genetic predisposition toward ALS, especially among soccer players, the G allele might be associated with disease severity. Further research is needed in order to explore the role of the ACSL rs6552828 polymorphism in ALS.

Genetic characteristics of competitive swimmers: a review.

A successful swimming performance is a multi-factorial accomplishment, resulting from a complex interaction of physical, biomechanical, physiological and psychological factors, all of which are strongly affected by the special medium of water as well as by genetic factors. The nature of competitive swimming is unique, as most of the competitive events last less than four minutes. Yet training regimens have an endurance nature (many hours and many kilometres of swimming every day), which makes it impossible to classify swimming by definitions of aerobic-type or anaerobic-type events, as in track and field sports. Therefore, genetic variants associated with swimming performance are not necessarily related to metabolic pathways, but rather to blood lactate transport (MCT1), muscle functioning (IGF1 axis), muscle damage (IL6) and others. The current paper reviews the main findings on the leading 12 genetic polymorphisms (located in the ACE, ACTN3, AMPD1, BDKRB2, IGF1, IL6, MCT1, MSTN, NOS3, PPARA, PPARGC1A, and VEGFR2 genes) related to swimming performance, while taking into consideration the unique environment of this sport.

Genetic Basis for the Dominance of Israeli Long-Distance Runners of Ethiopian Origin.

ABSTRACT: Ben-Zaken, S, Meckel, Y, Nemet, D, Kassem, E, and Eliakim, A. Genetic basis for the dominance of Israeli long-distance runners of Ethiopian origin. J Strength Cond Res 35(7): 1885-1896, 2021-Israeli long-distance runners of Ethiopian origin have a major influence on the track and field long-distance record table. The aim of this study was to determine whether genetic characteristics contribute to this long-distance dominance. We assessed polymorphisms in genes related to endurance (PPARD T/C), endurance trainability (ACSL A/G), speed (ACTN3 R/X), strength (AGT T/C), and the recovery from training (MTC1 A/T and IL6 G/C) among top Israeli long-distance runners of Ethiopian origin (n = 37), Israeli non-Ethiopian origin runners of Caucasian origin (n = 76), and Israeli nonathletic controls (n = 55). Israeli runners of Ethiopian origin had a greater frequency of the PPARD CC + PARGC1A Gly/Gly polymorphism, associated with improved endurance performance, compared with Israeli runners of non-Ethiopian origins (24 vs. 3%, respectively, p < 0.01); a lower frequency of the ACSL AA polymorphism, favoring endurance trainability (8 vs. 20%, respectively, p < 0.05); a greater frequency of the ACTN3 RR polymorphism, associated with sprint performance (35 vs. 20%, respectively, p < 0.05); a greater frequency of the MCT1 AA genotype, associated with improved lactate transport (65 vs. 45%, respectively, p < 0.05); and a lower frequency of IL-6 174C carriers, associated with reduced postexercise muscle damage (27 vs. 40%, respectively, p < 0.01). There was no difference in the frequency of AGT T/C gene polymorphism between the long-distance runners of Ethiopian and non-Ethiopian origin. Frequencies of PPARD CC + PARGC1A Gly/Gly, MCT1 AA, IL-6 174C, and AGT polymorphism were significantly favorable among Ethiopian, but not among non-Ethiopian, origin runners compared with controls. Taken together, results suggest that genetically, the dominance of Israeli long-distance runners of Ethiopian origin relates not only to endurance polymorphisms but also to polymorphisms associated with enhanced speed performance and better training recovery ability.

Insulin-like Growth Factor Axis Genetic Score and Sports Excellence.

ABSTRACT: Ben-Zaken, S, Meckel, Y, Nemet, D, and Eliakim, A. Insulin-like growth factor axis genetic score and sports excellence. J Strength Cond Res 35(9): 2421-2426, 2021-It has been suggested that IGF1 polymorphisms associated with circulating IGF1 levels may be linked to elite short-distance running performance. This study assessed genetic score based on 6 polymorphisms related to the Insulin-like growth factor axis (rs7136446, rs35767, rs6220, rs680, rs2854744, and rs1805086) among elite Israeli runners and swimmers. One hundred sixty-one track and field athletes (123 men and 38 women, age 17-50 years) and 94 swimmers (61 men and 33 women, age 16-49 years) participated in the study. Athletes were divided into short-distance runners (SDRs, major event: 100-200-m sprints and jumps, n = 63) and long-distance runners (LDRs, major event: 5,000 m and marathon, n = 98). Swimmers were divided into short-distance swimmers (SDSs, major event: 50-100 m, n = 44) and long-distance swimmers (LDSs, major event: 400-1,500 m, n = 50). Groups were subdivided into top-level and national-level athletes. We calculated the IGF genetic score (IGF-GS) of all the subjects on a 0-100 scale. Top-level SDRs' mean IGF-GS (30.8 ± 11.7) was significantly higher (p < 0.006) compared with national-level SDRs' (20.5 ± 11.3) and top-level SDSs' (19.9 ± 8.5). Subjects with IGF-GS >25 had an increased odds ratio (OR) of being elite-level SDRs (OR: 4.2; 95% confidence interval: 0.68-26.09; p < 0.001). In summary, a combined assessment of 6 single-nucleotide polymorphisms, all known to modulate circulation IGF1 levels, was associated with a higher genetic score among SDRs, emphasizing the importance of the IGF system to land speed sports events but not to swimming events. Whether the IGF-GS may be used for selection of elite-level sprinters in early stages of their athletic career needs to be further investigated.

Genetic Variability Among Power Athletes: The Stronger vs. the Faster.

Ben-Zaken, S, Eliakim, A, Nemet, D, and Meckel, Y. Genetic variability among power athletes: the stronger vs. the faster. J Strength Cond Res XX(X): 000-000, 2019-Athletic events can be divided into "aerobic-type events" or "anaerobic-type events" based on energy usage. Power, speed, and strength are also used to specify sports subtypes. Weightlifters (WLs), sprinters, and jumpers feature high-intensity efforts lasting a few seconds. However, their performance requires different proportions of power, speed, and strength. The aim of the current study was to examine genetic differences between subtypes of anaerobic athletes in 3 genetic variants: ACTN3 R577X, which is associated with muscle contractions; AGT Met235Thr which is associated with muscle growth; and PPARD T/C, which is associated with aerobic capacity. Seventy-one sprinters and jumpers (S/J), 54 WLs, and 86 controls participated in the study. Genomic DNA was extracted from peripheral blood using a standard protocol. Genotypes were determined using a TaqMan allelic discrimination assay. The ACTN3 RR genotype frequency was significantly higher among S/J (39.4%) compared with WLs (22.2%) and controls (18.6%). The AGT Thr-Thr genotype frequency was significantly higher among WLs (25.9%) compared with S/J (4.2%) and controls (12.8%). PPARD T294C genotype frequencies did not differ between groups. The results suggest that there may be a specific genetic makeup enabling an athlete to excel in speed-oriented events (sprints), rather than in strength-oriented events (weightlifting).

A Fast Track to Hypoalgesia - The Anaerobic Exercise Effect on Pain Sensitivity.

Maximal anaerobic exercise, is a short high intensity effort, involves activation of the hypothalamus-pituitary-adrenal axis, and may suggest hypoalgesic effects. In addition, this exercise-induced muscle pain may contribute to hypoalgesia via the pain inhibits pain phenomenon, which is related to the diffuse noxious inhibitory control (DNIC) mechanism. We aimed to investigate whether: 1) a single bout of 30 s maximal anaerobic exercise has an analgesic effect on experimental pain sensitivity; 2) DNIC is the underlying mechanism of anaerobic exercise-induced hypoalgesia (EIH). Fifty healthy subjects participated. The experimental group performed the 'Wingate Anaerobic Test' (WAT) and controls set on the bikes without exercising. Psychophysical tests, performed before and after the intervention, in local and remote areas, included: heat (HPT) and pressure pain thresholds (PPT); suprathreshold heat and cold pain stimulation; the conditioned pain modulation (CPM) paradigm testing the DNIC mechanism. Following WAT, PPT and HPT increased (p<0.001) , pain ratings in response to heat and cold stimuli (p<0.001) and CPM (p=0.029) decreased compared with controls. No correlation was found between muscle pain, blood lactate level and EIH. To conclude WAT induces local and remote analgesic effects. The involvement of central pain modulatory processes with DNIC probably not the underline mechanism of EIH.

Effect of contact and no-contact small-sided games on elite handball players.

This study aimed to investigate the effect of contact (C-SSG) and no-contact (NC-SSG) handball small-sided games (SSGs) on motion patterns and physiological responses of elite handball players. Twelve male handball players performed 10 C-SSG and 10 NC-SSG while being monitored through the heart rate (HR) and rate of perceived exertion (RPE) as physiological responses and time-motion activities profile using video-match analysis. Both game conditions resulted in similar HR responses (P > 0.05), but the NC-SSG led to a higher RPE scores. The time-motion activity analysis featured NC-SSG with a greater amount of walking (855.6 ± 25.1 vs. 690.6 ± 35.2 m) and backward movements (187.5 ± 12.3 vs. 142.5 ± 8.7 m) combined with fast running (232.3 ± 8.5 vs. 159.7 ± 5.7 m) and sprinting (79.5 ± 4.7 vs. 39.7 ± 3.7 m) activities (P < 0.001). Conversely, C-SSG had a higher percentage of jogging and sideway movements associated with greater frequency of jumping (0.87 ± 0.09 vs. 0.31 ± 0.06 nr) and physical contact (1.82 ± 0.55 vs. 0.25 ± 0.03 nr) events (P < 0.001). No between-regimen differences were found for the number of throws (P = 0.745). In addition, the RPE was significantly correlated with fast running relative distances (r = 0.909, P < 0.001) and sprinting relative distances (r = 0.939, P < 0.001). In conclusion, this investigation showed that both C-SSG and NC-SSG in team handball can effectively represent specifically oriented exercises, according to the sport-task and the performance demands.

Effect of Small-Sided Games and Repeated Shuffle Sprint Training on Physical Performance in Elite Handball Players.

This study was designed to compare the effects of small-sided games (SSGs) and repeated shuffle sprint (RSS) training on repeated sprint ability (RSA) and countermovement jump (CMJ) tests performances of elite handball players. Eighteen highly trained players (24.8 ± 4.4 years) were assigned to either SSG or RSS group training protocols twice a week for 8 weeks. The SSG training consisted of 5 small-sided handball games with 3-a-side teams excluding goalkeepers. The RSS consisted of 2 sets of 14-17 of 20-m shuttle sprints and 9-m jump shots interspersed by 20-second recoveries. Before and after training, the following performance variables were assessed: speed on 10-m and 20-m sprint time, agility and RSA time, CMJ height, standing throw, and jump shot speed. Significant pre-to-post treatment improvements were found in all the assessed variables following both training protocols (multivariate analysis of variance, p ≤ 0.05). There was a significantly greater improvement on 10-m sprint, CMJ, and jump shooting, after the RSS in comparison with SSG training (+4.4% vs. +2.4%, +8.6% vs. +5.6%, and +5.5% vs. +2.7%, respectively). Conversely, agility and standing throwing showed lower improvements after RSS in comparison with SSG (+1.0% vs. +7.8% and +1.6% vs. +9.0%, respectively). These results indicate that these training methods are effective for fitness development among elite adult handball players during the last period of the competitive season. Specifically, SSG seems to be more effective in improving agility and standing throw, whereas RSS seems preferable in improving 10-m sprint, CMJ, and jump shot.

Polymorphism of the IGF-I System and Sports Performance.

The potential use genetic polymorphism, and in particularly polymorphism of hormone genes, as tool to predict athletic performance is currently very challenging. Recent studies suggest that single nucleotide polymorphisms in IGF-I and myostatin may be beneficial for endurance and short distance running, and may even be associated with elite performance. Polymorphism in IGF-I receptor may differentiate between the two edges of the endurance-power athletic performance running spectrum suggesting beneficial effects for endurance and prevent from success in power events. In contrast, and despite similar metabolic demands, the myostatin-IGF-I-IGF-IR system seems not to play an important role in swimming excellence. This suggests that combining different sport disciplines for sports genetic research purposes should be done with extreme caution. Finally, since any phenotype reflects a complex relationship between genes, environment, epigenetic factors, and the interactions between them, consulting the young athlete regarding future success cannot be based solely on genetic polymorphism.

Improving fitness of elite handball players: small-sided games vs. high-intensity intermittent training.

The present study was designed to compare the effects of high-intensity intermittent training (HIIT) and small-sided games (SSGs) training on fitness variables of elite handball players. Eighteen highly trained players (mean age ± SD: 25.6 ± 0.5 years) were assigned to either HIIT or SSGs group training protocols twice per week for 8 weeks. The HIIT consisted of 12-24 × 15 seconds of high-intensity runs interspersed by 15 seconds of recovery. The SSGs training consisted of 3 against 3 small-sided handball games. Both training methods were matched for exercise duration and recovery at each training session. Before and after 8-week training, the following fitness variables were assessed-speed: 10- and 20-m sprint time, agility: handball agility specific test (HAST), upper arm strength: 1 repetition maximum (1RM) bench press test, lower limb power: counter-movement jump tests with (CMJarm) and without (CMJ) arm movement, and aerobic fitness (yo-yo intermittent recovery test level 1 [YYIRTL1]). Significant improvement was found in the YYIRTL1 (23.3 and 26.3%, respectively), 10-m sprint (2.3 and 4.1%, respectively) and 20-m sprint (2.1 and 4%, respectively), HAST (1.1 and 2.2%, respectively), 1RM bench press (6.8 and 12.3%, respectively), CMJ (7.4 and 10.8%, respectively), and CMJarm (6.4 and 8.9%, respectively) following training in both groups (p ≤ 0.05 for all). There was a significantly greater improvement in 10- and 20-m sprint, HAST, 1RM, CMJ, and CMJarm following the SSGs training compared with the HIIT (p ≤ 0.05 for all). These results indicated that both HIIT and SSGs are effective training methods for fitness development among elite adult handball players. However, SSGs training may be considered as the preferred training regimen for improving handball-specific fitness variables during the in-season period.

Rhabdomyolysis After Out-of-Water Exercise in an Elite Adolescent Water Polo Player Carrying the IL-6 174C Allele Single-Nucleotide Polymorphism.

We present an adolescent elite water polo player who despite a genetic predisposition to develop exercise-induced severe muscle damage due to carrying the IL-6 174C allele single-nucleotide polymorphism, developed acute rhabdomyolysis only after a vigorous out-of-water training, suggesting that water polo training may be more suitable for genetically predisposed athletes.

Relationships Among Two Repeated Activity Tests and Aerobic Fitness of Volleyball Players.

The purpose of the study was to determine performance indices of a repeated sprint test (RST) and to examine their relationships with performance indices of a repeated jump test (RJT) and with aerobic fitness among trained volleyball players. Sixteen male volleyball players performed RST (6 × 30 m sprints), RJT (6 sets of 6 consecutive jumps), and an aerobic power test (20-m Shuttle Run Test). Performance indices for the RST and the RJT were (a) the ideal 30-m run time (IS), the total run time (TS) of the 6 sprints, and the performance decrement (PD) during the test and (b) the ideal jump height (IJ), the total jump height (TJ) of all the jumps, and the PD during the test, respectively. No significant correlations were found between performance indices of the RST and RJT. Significant correlations were found between PD, IS, and TS in the RST protocol and predicted peak V[Combining Dot Above]O2 (r = -0.60, -0.75, -0.77, respectively). No significant correlations were found between performance indices of the RJT (IJ, TJ, and PD) and peak V[Combining Dot Above]O2. The findings suggest that a selection of repeated activity test protocols should acknowledge the specific technique used in the sport, and that a distinct RJT, rather than the classic RST, is more appropriate for assessing the anaerobic capabilities of volleyball players. The findings also suggest that aerobic fitness plays only a minor role in performance maintenance throughout characteristic repeated jumping activity of a volleyball game.

IGF-I and IGF-I receptor polymorphisms among elite swimmers.

In recent years several genetic polymorphisms related to the GH-IGF-I axis were suggested to promote athletic excellence in endurance and power sports. We studied the presence of the C-1245T SNP (rs35767), a nucleotide substitution in the promoter region of the IGF-I gene, and the presence of the 275124A > C SNP (rs1464430), a common nucleotide substitution in the intron region of the IGF-I receptor (IGF-IR) gene in elite long and short-distance swimmers compared with nonphysically active controls. The rare T/T IGF-I polymorphism was found only in 5.3% of the long-distance swimmers, and was not found at all in the short-distance swimmers or among the control group participants. The prevalence of the IGF-I receptor AA genotype was significantly lower in the swimming group as a whole (35%) compared with the control group (46%), in particularly due to reduced frequency of the AA genotype among short-distance swimmers (26%). In contrast to previous reports in elite endurance and power track and field athletes, single nucleotide polymorphisms of the IGF-I and the IGF-IR were not frequent among elite Israeli short- and long-distance swimmers emphasizing the importance of other factors for excellence in swimming. The results also suggest that despite seemingly similar metabolic characteristics different sports disciplines may have different genetic polymorphisms. Thus, combining different disciplines for sports genetic research purposes should be done with extreme caution.

Repeated sprint ability in young soccer players at different game stages.

The purpose of this study was to determine the repeated sprint ability (RSA) of young (16.9 ± 0.5 years) soccer players at different game stages. Players performed repeated sprint test (RST) (12 × 20 m) after warm-up before a game, at half-time, and after a full soccer game, each on a different day, in a random order. The ideal (fastest) sprint time (IS) and total (accumulative) sprint time (TS) were significantly slower at the end of the game compared with those after the warm-up before the game (p < 0.01 for each). Differences between IS and TS after the warm-up before the game and at half-time, and between half-time and end of the game, were not statistically significant. There was no significant difference in the performance decrement during the RST after warm-up before the game, at half-time, or the end of the game. Significant negative correlation was found between predicted V[Combining Dot Above]O2 and the difference between TS after the warm-up before the game and the end of the game (r = -0.52), but not between predicted V[Combining Dot Above]O2 and the difference in any of the RST performance indices between warm-up before the game and half-time, or between half-time and the end of the game. The findings indicate a significant RSA reduction only at the end but not at the half-time of a soccer game. The results also suggest that the contribution of the aerobic system to soccer intensity maintenance is crucial, mainly during the final stages of the game.

Effect of gender on the GH-IGF-I response to anaerobic exercise in young adults.

Exercise-associated effects on the growth hormone-insulin-like growth factor-I (GH-IGF-I) axis were studied, mainly after aerobic exercise. We determined the gender effect on the GH-IGF-I axis response to a standard all-out Wingate anaerobic test (WAnT) in healthy active young adult men and women (men = 12 and women = 16; age range: 24-34 years). Blood samples for GH and IGF-I, key elements of the GH-IGF-I axis, were collected before and 20, 30, 40, and 60 minutes after the beginning of exercise. In addition, we collected postexercise blood lactate levels. Postexercise lactate levels were higher among men; however, this difference did not reach statistical significance (13.8 ± 1.3 vs. 11.1 ± 1.0 mmol·L, respectively; p = 0.1). The WAnT was associated with a significant increase in GH in both genders. However, GH peak was greater among women (10.8 ± 1.8 vs. 5.6 ± 1.4 ng·ml, in women and men, respectively; p < 0.01). In addition, postexercise GH peak occurred significantly earlier in female (20 minutes) compared with male participants (40 minutes). Exercise was associated with a significant increase in IGF only among men (from 166.8 ± 8.4 to 186.9 ± 9.3; p < 0.02); however, no significant between-gender effect was found. In summary, supramaximal anaerobic exercise was associated with a greater and earlier postexercise GH peak in women compared with men. All together, the results suggest anaerobic exercise-related anabolic-type hormonal response.

Long term effects of a health promotion intervention in low socioeconomic Arab- Israeli kindergartens.

BACKGROUND: Obesity is the most common chronic pediatric disease in westernized, especially low socioeconomic societies. We previously demonstrated the beneficial effects of a randomized prospective school-based health education program for low socioeconomic status Arab-Israeli kindergarten children. METHODS: To examine whether the effects of our program on nutrition and physical activity knowledge and preferences, anthropometric measures, and fitness persisted one year after the end of intervention. RESULTS: At one year following the intervention BMI and BMI percentiles approached baseline level in both the intervention (16.4 ± 0.2 kg/m2 and 61.5 ± 2.4%, respectively) and control group participants (16.5 ± 0.2 kg/m2 and 58.5 ± 3.3%, respectively). Yet, a year after the end of the intervention, the decrease in BMI%ile from baseline was significantly greater in the intervention group (-7.8 ± 1.5 vs. -1.9 ± 1.9, p<0.012). Nutritional and physical activity knowledge and preferences, and physical fitness remained significantly elevated in the intervention compared to the control group participants. CONCLUSIONS: The beneficial effects of a kindergarten dietary-physical activity intervention applied by the kindergarten teachers, on nutrition and physical activity knowledge and preferences, fitness, and BMI percentile were evident one year after the end of intervention. This promising program may play a role in health promotion, prevention and treatment of childhood obesity.

Genetic profiles and prediction of the success of young athletes' transition from middle- to long-distance runs: an exploratory study.

The aim of the study was to assess whether an aerobic-favoring genetic profile can predict the success of a shift from middle- to long-distance running. Thirteen elite middle-distance runners were divided into successful and nonsuccessful groups in their shift toward long-distance runs. All the runners began their training program at the age of 14-15, and after 6-7 years, changed focus and adjusted their training program to fit longer running distances. The participants' personal records in the longer events were set at the age of 25-27, about 3-5 years after the training readjustment took place. The endurance genetic score based on 9 polymorphisms was computed as the endurance genetic distance score (EGDS9). The power genetic distance score (PGDS5) was computed based on 5 power-related genetic polymorphisms. The mean EGDS9 was significantly higher among the successful group than the nonsuccessful group (37.1 and 23.3, respectively, p < .005, effect size 0.75), while the mean PGDS5 was not statistically different between the 2 groups (p = .13). Our findings suggest the possible use of genetic profiles as an added tool for determining appropriate competitive transition and specialization in young athletes involved in early phases of talent development.

Training reduces catabolic and inflammatory response to a single practice in female volleyball players.

We examined the effect of training on hormonal and inflammatory response to a single volleyball practice in elite adolescent players. Thirteen female, national team level, Israeli volleyball players (age 16.0 ± 1.4 years, Tanner stage 4-5) participated in the study. Blood samples were collected before and immediately after a typical 60 minutes of volleyball practice, before and after 7 weeks of training during the initial phase of the season. Training involved tactic and technical drills (20% of time), power and speed drills (25% of time), interval sessions (25% of time), endurance-type training (15% of time), and resistance training (15% of time). To achieve greater training responses, the study was performed during the early phase (first 7 weeks) of the volleyball season. Hormonal measurements included the anabolic hormones growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF-binding protein-3, the catabolic hormone cortisol, the proinflammatory marker interleukin-6 (IL-6), and the anti-inflammatory marker IL-1 receptor antagonist. Training led to a significant improvement of vertical jump, anaerobic properties (peak and mean power by the Wingate Anaerobic Test), and predicted VO2max (by the 20-m shuttle run). Volleyball practice, both before and after the training intervention, was associated with a significant increase of serum lactate, GH, and IL-6. Training resulted in a significantly reduced cortisol response ([INCREMENT]cortisol: 4.2 ± 13.7 vs. -4.4 ± 12.3 ng · ml, before and after training, respectively; p < 0.02), and IL-6 response ([INCREMENT]IL-6: 1.3 ± 1.0 vs. 0.3 ± 0.4 pg · ml, before and after training, respectively; p < 0.01) to the same relative intensity volleyball practice. The results suggest that along with the improvement of power and anaerobic and aerobic characteristics, training reduces the catabolic and inflammatory response to exercise.

Effect of rhythm on the recovery from intense exercise.

Motivational music (music that stimulates physical activity) was previously shown to enhance the recovery from intense exercise. The aim of the present study was to isolate the effect of rhythm (presumed to be the most effective factor of motivational music) on the recovery from intense exercise. Ten young adult active men (age: 26.1 ± 1.7 years) performed 6-minute run at peak oxygen consumption speed, at 3 separate visits (random order). At 1 visit, no music was played during the recovery after exercise. In the other visits, participants listened to motivational music that was previously shown to enhance recovery (a Western CD collection of greatest hits of all times converted to dance style, 140 b·min, strong bit, played by portable MP3 device using headphones at a volume of 70 dB) or only to the rhythm beats derived from the same songs. Mean heart rate (HR), rating of perceived exertion (RPE), number of steps (measured by step counter) and blood lactate concentrations were determined at 3, 6, 9, 12, and 15 minutes of the recovery. There was no difference in HR changes during the recovery at all conditions. Compared with the recovery without music, listening to motivational music during recovery was associated with significant greater number of steps, lower absolute lactate levels, and greater mean decrease of RPE. Listening only to rhythm beats, derived from the same music, during the recovery was associated with significant greater number of steps and lower absolute lactate levels compared to recovery without music. Music was significantly more effective than rhythm only in the absolute mean number of steps. The beneficial effect of both music and rhythm was greater toward the end of the recovery period. Results suggest that listening to music during nonstructured recovery can be used by professional athletes to enhance recovery from intense exercise. Rhythm plays a very important role in the effect of music on recovery and can be used to enhance nonstructured recovery when music is unavailable or when cultural barriers and individual music preferences may apply. The optimal music and rhythm selection is yet to be determined.