Effects of Knee-Pelvis Coordination Sequence During Block Start on First Step Performance in Elite Sprint Athletes

Purpose: There is an ongoing debate whether highly trained athletes are less responsive to the ergogenic properties of nitrate. We assessed the effects of nitrate supplementation on plasma nitrate and nitrite concentrations and repeated-sprint performance in recreational, competitive and elite sprint athletes. Methods: In a randomized double-blinded cross-over design, recreational cyclists (n = 20), national talent speed-skaters (n = 22) and Olympic-level track cyclists (n = 10) underwent two 6-day supplementation periods; 140 mL/d nitrate-rich (BR; ∼800 mg/d) and nitrate-depleted (PLA; ∼0.5 mg/d) beetroot juice. Blood samples were collected and three 30-s Wingate tests were performed. Results: Plasma nitrate and nitrite concentrations were higher following BR vs PLA (P < .001), with no differences between sport levels (all P > .10). Peak power over the three Wingates was not different between BR and PLA (1338 ± 30 vs 1333 ± 30 W; P = .62), and there was no interaction between treatment (BR-PLA) and Wingate number (1-2-3; P = .48). Likewise, mean power did not differ between BR and PLA (P = .86). In contrast, time to peak power improved by ∼2.8% following BR vs PLA (P = .007). This improvement in BR vs PLA was not different between Wingate 1, 2 and 3. Moreover, the effects of BR vs PLA did not differ between sport levels for any Wingate parameter (all P > .30). Conclusion: The plasma and repeated-sprint performance responses to beetroot juice supplementation do not differ between recreational, competitive and elite sprint athletes. Beetroot juice supplementation reduces time to reach peak power, which may improve the capacity to accelerate during high-intensity and sprint tasks in recreational as well as elite athletes.

The angiotensin-converting enzyme (ACE) and the alpha-actinin-3 (ACTN3) genes are two of the most studied "performance genes" and both have been associated with sprint/power phenotypes and elite performance. To investigate the association between the ACE and the ACTN3 genotypes and sprint athlete status in elite Jamaican and US African American sprinters. The ACTN3 R577X and the ACE I/D and A22982G (rs4363) genotype distributions of elite Jamaican (J-A; N = 116) and US sprinters (US-A; N = 114) were compared with controls from the Jamaican (J-C; N = 311) and US African American (US-C; N = 191) populations. Frequency differences between groups were assessed by exact test. For ACTN3, the XX genotype was found to be at very low frequency in both athlete and control cohorts (J-C = 2%, J-A = 3%, US-C = 4%, US-A = 2%). Athletes did not differ from controls in ACTN3 genotype distribution (J, P = 0.87; US, P = 0.58). Similarly, neither US nor Jamaican athletes differed from controls in genotype at ACE I/D (J, P = 0.44; US, P = 0.37). Jamaican athletes did not differ from controls for A22982G genotype (P = 0.28), although US sprinters did (P = 0.029), displaying an excess of heterozygotes relative to controls but no excess of GG homozygotes (US-C = 22%, US-A = 18%). Given that ACTN3 XX genotype is negatively associated with elite sprint athlete status, the underlying low frequency in these populations eliminates the possibility of replicating this association in Jamaican and US African American sprinters. The finding of no excess in ACE DD or GG genotypes in elite sprint athletes relative to controls suggests that ACE genotype is not a determinant of elite sprint athlete status.

Classic track-and-field studies demonstrated that elite endurance athletes exhibit a slow muscle typology, whereas elite sprint athletes have a predominant fast muscle typology. In elite cycling, conclusive data on muscle typology are scarce, which may be due to the invasive nature of muscle biopsies. The noninvasive estimation of muscle typology through the measurement of muscle carnosine enabled to explore the muscle typology of 80 world-class cyclists of different disciplines. The muscle carnosine content of 80 cyclists (4 bicycle motor cross racing [BMX], 33 track, 8 cyclo-cross, 24 road, and 11 mountain bike) was measured in the soleus and gastrocnemius by proton magnetic resonance spectroscopy and expressed as a z-score relative to a reference population. Track cyclists were divided into track sprint and endurance cyclists based on their Union Cycliste Internationale (UCI) ranking. Moreover, road cyclists were further characterized based on the percentage of UCI points earned during either single and multistage races. BMX cyclists (carnosine aggregate z-score of 1.33) are characterized by a faster muscle typology than track, cyclo-cross, road, and mountain bike cyclists (carnosine aggregate z-score of -0.08, -0.76, -0.96, and -1.02, respectively; P < 0.05). Track cyclists also possess a faster muscle typology compared with mountain bikers (P = 0.033) and road cyclists (P = 0.005). Moreover, track sprinters show a significant faster muscle typology (carnosine aggregate z-score of 0.87) compared with track endurance cyclists (carnosine aggregate z-score of -0.44) (P < 0.001). In road cyclists, the higher the carnosine aggregate z-score, the higher the percentage of UCI points gained during single-stage races (r = 0.517, P = 0.010). Prominent differences in the noninvasively determined muscle typology exist between elite cyclists of various disciplines, which opens opportunities for application in talent orientation and transfer.

Dougan, A, Latella, C, Nagatani, T, Lockie, RG, O'Brien, E, and Haff, GG. The effect of resisted sprint training on force-velocity profile change: A systematic review and meta-analysis. J Strength Cond Res 39(11): 1203-1215, 2025-This meta-analysis evaluated the effectiveness of resisted sprint training (RST) compared with unresisted sprint training (URST) programs to positively influence horizontal force-velocity (F-V) profile variables and acceleration performance in trained individuals. Searches were conducted through PubMed, Web of Science, and SPORTDiscus without year restriction. Included studies (a) used RST by towing/pushing a load as a training modality, (b) were published in a scientific journal, (c) were published in English, (d) were an original intervention, (e) measured pre- and postintervention horizontal F-V profiles, (f) identified training parameters including RST load used, (g) the training intervention was ≥4 weeks in duration or ≥8 sessions, and (h) included a control group that performed URST. After screening, 7 studies met the inclusion criteria. Raw data (mean ± SD or range) were extracted, and standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated for all outcomes. Significance was set at p < 0.05. Resisted sprint training significantly improved force (SMD = 0.47, CI: [0.12-0.83], p = 0.002), power (SMD = 0.53 [0.17-0.88], p < 0.001), RF peak (SMD = 0.70 [0.03-1.37], p = 0.029), and 5 m (SMD = -0.81 [-1.26 to 0.36], p < 0.001), 10 m (SMD = -0.80 [-1.39 to 0.21], p = 0.007), and 20 m sprint performance (SMD = -1.09 [-1.60 to 0.59], p < 0.001) during sprinting when compared with URST. Resisted sprint training represents an efficient means to increase key horizontal F-V profile variables. The findings suggest that RST may complement or be favored over URST to improve early-to-mid acceleration performance, horizontal force, or power, but further research is required in elite sprint athletes and to determine the effect that RST load and volume have on the adaptability of the F-V profile.

A common nonsense polymorphism (R577X) in the ACTN3 gene results in complete deficiency of the fast skeletal muscle fiber protein alpha-actinin-3 in an estimated one billion humans worldwide. The XX null genotype is under-represented in elite sprint athletes, associated with reduced muscle strength and sprint performance in non-athletes, and is over-represented in endurance athletes, suggesting that alpha-actinin-3 deficiency increases muscle endurance at the cost of power generation. Here we report that muscle from Actn3 knockout mice displays reduced force generation, consistent with results from human association studies. Detailed analysis of knockout mouse muscle reveals reduced fast fiber diameter, increased activity of multiple enzymes in the aerobic metabolic pathway, altered contractile properties, and enhanced recovery from fatigue, suggesting a shift in the properties of fast fibers towards those characteristic of slow fibers. These findings provide the first mechanistic explanation for the reported associations between R577X and human athletic performance and muscle function.

ACTN3 Genotype Is Associated with Human Elite Athletic Performance

The angiotensin converting enzyme (ACE) polymorphism is the most studied genetic marker in the field of human performance. There is a continuing debate in the literature regarding the possible association of ACE genotypes and elite athletic status. In fact, despite recent studies having identified no significant associations in athletes from mixed sporting disciplines, other researchers suggest that the insertion (I) variant may be associated with elite endurance performance, and the deletion (D) variant can be over-represented among elite sprinters. The purpose of the present study was to determine, for the first time, the association between the ACE genotypes and sprint athlete status among elite Italian gymnasts. To test this hypothesis, we assessed 33 elite Italian gymnasts (17 males, 16 females) and a control group of 53 (31 males, 22 females) unrelated sedentary individuals. DNA was extracted from each participant using a buccal swab and the ACE I/D polymorphism was determined using PCR while different amplified fragments were detected by electrophoresis using agarose gel and ethidium bromide staining. The ACE genotypes and allele frequencies among gymnasts (DD, ID, II=0.39, 0.48, 0.12, respectively; D allele=0.64) were not significantly different from those of Italian sedentary controls (DD, ID, II=0.39, 0.45, 0.15, respectively; D allele=0.62). However, the frequencies of our control group were similar to those observed in a sample of Italian sedentary individuals, and different to those of the general Caucasian population reported by other authors. Furthermore, the frequencies of our control group did not differ from those reported in other association studies involving elite sprint athletes. Our results suggest a lack of association between the ACE I/D polymorphism and elite gymnastics performance in Italians.

The study aimed to evaluate the lower limb skin temperature (Tsk) and blood concentrations of lactate (LA) and ammonia (NH3) during exercise and recovery. Eleven elite sprint athletes (25 ± 3.4 yrs) and 11 elite endurance athletes (24.45 ± 5.4 yrs) performed an incremental running test until exhaustion. Body composition was estimated using the DXA method. Thermograms of the anterior and posterior surfaces of the lower limbs were recorded at rest, before each test stage (every 3 min, starting from 10 km h−1 and increasing by 2 km h−1), and in the 5th, 10th, 15th, 20th, and 30th minute of recovery. Endurance athletes had a higher maximum oxygen uptake than sprint athletes (5.0 ± 0.7 vs 4.3 ± 0.4 l·kg−1, p = 0.018), lower percentage of lean content (79 ± 2 vs 83 ± 2%, p < 0.001), and a higher percentage of fat content in the lower limbs (17 ± 2 vs 12 ± 2%, p < 0.001). In both groups, a significant decrease in Tsk was observed compared to resting value (endurance athletes—31.5 ± 0.6 °C; sprint athletes—32.3 ± 0.6 °C), during exercise (p < 0.001) and rewarming during recovery (p < 0.001). However, endurance athletes had a lower Tsk than sprint athletes at the exhaustion point (30.0 ± 1.1 vs 31.6 ± 0.8 °C, p < 0.05) and the pattern of change in Tsk differed between groups (p < 0.001). Tsk in the endurance athletes group decreased throughout the exercise protocol and returned more rapidly to initial values during recovery, while Tsk in the sprint group stabilised between moderate intensity and exhaustion, recovering more slowly after exercise. Both LA (endurance athletes—max 10.2 ± 1.5; sprint athletes—max 10.1 ± 1.4 mmol⋅L−1, p < 0.001) and NH3 (endurance athletes—max 75.6 ± 11.5; sprint athletes—max 76.7 ± 9.0 mmol⋅L−1, p < 0.001) increased during exercise and decreased during recovery (p < 0.001). During exercise, lower levels and slower increases in LA were observed during exercise in the endurance athletes’ group (p < 0.05). A negative correlation was revealed between Tsk and fat percentage (r = −0.43 to −0.71, p < 0.05). Tsk was positively correlated with LA during recovery (r = 0.43 to 0.48, p < 0.05), and negatively during recovery (r = −0.45 to −0.54, p < 0.05). Differences between groups in maximum aerobic capacity, the pattern of change in Tsk, and the correlation between Tsk and LA suggest that individuals who decrease less Tsk during exercise and higher Tsk during recovery are those with better aerobic capacity. In addition, athletes with less body fat dissipate heat from their tissues more efficiently.

BackgroundWe have previously reported on paucity of mitochondrial DNA (mtDNA) haplogroups J and K among Finnish endurance athletes. Here we aimed to further explore differences in mtDNA variants between elite endurance and sprint athletes. For this purpose, we determined the rate of functional variants and the mutational load in mtDNA of Finnish athletes (n = 141) and controls (n = 77) and determined the sequence variation in haplogroups.ResultsThe distribution of rare and common functional variants differed between endurance athletes, sprint athletes and the controls (p = 0.04) so that rare variants occurred at a higher frequency among endurance athletes. Furthermore, the ratio between rare and common functional variants in haplogroups J and K was 0.42 of that in the remaining haplogroups (p = 0.0005). The subjects with haplogroup J and K also showed a higher mean level of nonsynonymous mutational load attributed to common variants than subjects with the other haplogroups. Interestingly, two of the rare variants detected in the sprint athletes were the disease-causing mutations m.3243A > G in MT-TL1 and m.1555A > G in MT-RNR1.ConclusionsWe propose that endurance athletes harbor an excess of rare mtDNA variants that may be beneficial for oxidative phosphorylation, while sprint athletes may tolerate deleterious mtDNA variants that have detrimental effect on oxidative phosphorylation system. Some of the nonsynonymous mutations defining haplogroup J and K may produce an uncoupling effect on oxidative phosphorylation thus favoring sprint rather than endurance performance.

The genetic underpinnings of elite sprint and power performance remain largely elusive. This study aimed to identify genetic variants associated with this complex trait as well as to understand their functional implications in elite sprint and power performance. We conducted a multi-phase genome-wide association study (GWAS) in world-class sprint and power athletes of West African and East Asian ancestry and their geographically matched controls. We carried out genotype imputation, replications for the top GWAS signal rs10196189 in two European cohorts, and gene-based and tissue-specific functional network analyses. For the first time, we uncovered the G-allele of rs10196189 in the Polypeptide N-Acetylgalactosaminyltransferase 13 (GALNT13) being significantly associated with elite sprint and power performance (P = 2.13E-09 across the three ancestral groups). Moreover, we found that GALNT13 expression level was positively associated with the relative area occupied by fast-twitch muscle fibers in the vastus lateralis muscle. In addition, significant and borderline associations were observed for BOP1, HSF1, STXBP2, GRM7, MPRIP, ZFYVE28, CERS4, and ADAMTS18 in cross-ancestry or ancestry-specific contexts, predominantly expressed in the nervous and hematopoietic systems. From the elite athlete cohorts, we further identified thirty-six previously uncharacterized genes linked to host defence, leukocyte migration, and cellular responses to interferon-gamma, and four genes – UQCRFS1, PTPN6, RALY and ZMYM4 – associated with aging, neurological conditions, and blood disorders. Taken together, these results provide new biological insights into the genetic basis of elite sprint and power performance and, importantly, offer valuable clues to the molecular mechanisms underlying elite athletic performance, health and disease.

ABSTRACTThe hamstrings are critical for athletic performance; however, no study has examined differences in hamstring muscle‐tendon geometry (cross‐sectional area/volume) and muscle typology (proportion of Type I/II fibers) between elite sprinters/jumpers and recreationally active individuals. This study aimed to compare hamstring geometry and typology between these groups and examine how these characteristics relate to sprint and strength performance. Elite sprint and jump athletes (n = 15, 3 female, 21.7 ± 2.2 y, 180.6 ± 9.9 cm, 72.2 ± 9.6 kg) and recreationally active individuals (n = 15, 4 female, 25.7 ± 3.0 y, 176.0 ± 9.5 cm, 76.3 ± 17.6 kg) completed sprint and eccentric knee flexor strength testing. Magnetic resonance imaging and spectroscopy were used to assess hamstring muscle‐tendon geometry and typology, respectively. Compared to recreationally active individuals, elite athletes had larger hamstring muscles (all muscles, mean difference: 59.75–150.45 cm3, p < 0.009), biceps femoris long head (BFlh) proximal aponeuroses (1.09 cm3, p < 0.001), BF short head distal aponeuroses (1.24 cm3, p = 0.002), semimembranosus proximal free tendons (0.75 cm3, p = 0.024) and aponeuroses (2.29 cm3, p < 0.001), semitendinosus distal free tendons (0.49 cm3, p = 0.01) and BFlh proximal aponeurosis interface areas (10.43 cm2, p < 0.001). Elite athletes also had 1.5 times greater estimated proportion of Type II fibers (p < 0.001). Medial hamstring geometry and muscle typology explained the greatest variance in maximal sprint speed (R2 = 0.65), while BFlh and semimembranosus muscle volumes with semitendinosus tendon volume explained the greatest variance in eccentric knee flexor strength (R2 = 0.59). Elite athletes had larger hamstring muscles, aponeuroses, and free tendons, and a greater estimated proportion of Type II fibers than recreationally active individuals. These structural and compositional differences likely contribute to their superior sprint and strength performance.

The aim of this study was to establish the percentage of sickle cell trait (SCT) carriers among French West Indian sprinters selected for the French National Team in 2000. The investigation determined the number of SCT carriers and the number of national records they had established. Sixteen athletes were indexed (6 males and 10 females). The athletes were within the ranges of 20-33 years, 161-186 cm and 60-80 kg. The results showed the presence of SCT carriers in this population among whom three were SCT carriers (2 males and 1 female) (18.75%). Moreover, there is a significantly higher percentage of titles and records held by the SCT carriers (38.6% and 50%, respectively). In conclusion, this study shows that sickle cell trait carriers are able to perform sprint exercises at the highest levels, and it further indicates that brief and explosive exercise involving mainly the alactic anaerobic metabolism may be enhanced by HbS.

Background:There exists a paucity of anthropometric and kinematic data for elite United States (US) sprinters and further analysis of how these variables correlate with sprint velocity in practice is warranted.Aim:The purpose of this investigation was to examine the relationship of anthropometric and kinematic variables and practice sprint velocity of elite sprint athletes when separated by gender.Methods:Participants included elite US 100 m sprinters (total: n=38, male: n=19, female: n=19). Inclusion criteria were participation in the 100 m semifinals or finals at the US Outdoor National Championships from 2015 to 2019. Anthropometric data and 300 Hz video during maximum velocity sprinting were collected during a practice session and video was digitized to determine the kinematic variables of interest. Relationships with maximal sprint velocity were assessed using Pearson’s correlation coefficient and linear regression analysis.Results:Males showed significant unadjusted relationships between practice velocity and step length (r=0.668; P=0.002), horizontal backward foot velocity at touchdown (r=0.459; P=0.048), and upper leg full extension angle (r=–0.585; P=0.009). Multiple regression analysis found that when adjusting for these three variables, step length was the only significant predictor of practice velocity in males which accounted for 44.6% of the variability in practice velocity in males. The females showed a significant relationship between practice velocity and step length (r=0.629; P=0.004) which accounted for 39.5% of the variability in practice velocity.Conclusion:These results provide researchers and coaches with important information regarding the anthropometric and kinematic variables related to elite top speed sprinting performance.Relevance for Patients:Training focused on increasing step length may be an efficient way to improve velocity in practice.

Background:This study investigated the effect of sodium bicarbonate (HCO3−) intake on maximum muscle strength variables during eight weeks of high-intensity exercise of a sprinter.Methods:The study was conducted on 30 elite sprint athletes in Seoul, Republic of Korea as in 2016 with ≥3 yr of an athletic career by assigning 10 each to three groups (the control, training, and sodium bicarbonate-training combination groups [HCO3− and training group]). The training group and the HCO3− and training group participated in a high-intensity exercise program for 90 min per session, five days a week for eight weeks in total, and it involved 80%–90% heart rate max intensity increase every 2–3 weeks, and allocation of internal exercise, aquatic exercise, and hill exercise. HCO3− was provided to the HCO3− and training group, and involved an intake of 300 g of HCO3− per 1 kg body weight, once a day, 90 min prior to the high-intensity exercise program for eight weeks.Results:HCO3− intake during high-intensity training had a positive effect on maximum muscle strength. A positive effect was observed in the HCO3− and training groups; however, the effect on maximum muscle strength was stronger in the HCO3− and training groups. In particular, the effect on maximum muscle strength was observed during extension than during flexing starting from the fourth week of the exercise program with HCO3− intake.Conclusion:HCO3− intake during 8 weeks of high-intensity training began to have a positive effect on maximum muscle strength. Therefore, HCO3− intake during high-intensity exercise is effective in improving exercise capacity.

Sickle Cell Trait in French West Indian Elite Sprint Athletes