The Effects of Shortening the Distance between Hurdles during Training

The high hurdle events consists of succesive changes in cycling (sprinting) and non-cycling (hurdle clearing) movements. This characteristic is the basic element of the events correct technique. It is acceptable that in jumping events, the high performance athletes follow a distinct preparatory phase just before the actual jump in order to achieve a position that facilitates a better transition from running to jumping conditions (Nixdorf. 1983, Tsarouchas. 1986). The purpose of the present study was to investigate shorter distances between the hurdles during training, as a means to improve the preparation phase of hurdle clearance

The neuromuscular, biochemical, and endocrine responses to a single-session vs. double-session training day in elite athletes

Purpose: The aim of this study was to compare the acute neuromuscular, biochemical, and endocrine responses of a training day consisting of a speed session only to performing a speed and weight training session on the same day. Methods: Fifteen male academy level rugby players completed two protocols in a randomized order. The speed only protocol involved performing 6 maximal effort repetitions of 50m running sprints with 5 minutes recovery between each sprint, while the speed and weights protocol involved the same sprinting session but was followed 2h post by a lower body weights session consisting of 4 sets of 5 back squat and Romanian deadlift at 85% 1RM. Testosterone, cortisol, creatine kinase, lactate, and perceived muscle soreness were determined immediately before, immediately after, 2h post, and 24h post both protocols. Peak power, relative peak power, jump height, and average rate of force development were determined from a counter movement jump (CMJ) at the same time points. Results: At 24h post, muscle soreness was significantly higher following the speed and weights protocol compared to speed only protocol (effect size eta2= .253, F=4.750, p < 0.05). There was no significant difference between any of the CMJ variables at any of the post training time points. Likewise creatine kinase, testosterone, and cortisol were unaffected by the addition of a weight training session. Conclusion: These data indicate that the addition of a weight training session 2h post a speed session, while increasing the perception of fatigue the following day, does not result in a difference in endocrine response or in neuromuscular capability

Association analysis of ACE and ACTN3 in Elite Caucasian and East Asian Swimmers

PURPOSE: Polymorphic variation in the angiotensin-converting enzyme (ACE) and alpha-actinin-3 (ACTN3) genes has been reported to be associated with endurance and/or power-related human performance. Our aim was to investigate whether polymorphisms in ACE and ACTN3 are associated with elite swimmer status in Caucasian and East Asian populations. METHODS: ACE I/D and ACTN3 R577X genotyping was carried out for 200 elite Caucasian swimmers from European, Commonwealth, Russian and American cohorts (short and middle distance, SMD &le; 400 m, n = 130; long distance, LD&nbsp;greater than&nbsp;400 m, n = 70) and 326 elite Japanese and Taiwanese swimmers (short distance, SD &le; 100 m, n = 166; middle distance, MD: 200 - 400 m, n = 160). Genetic associations were evaluated by logistic regression and other tests accommodating multiple testing adjustment. RESULTS: ACE I/D was associated with swimmer status in Caucasians, with the D-allele being overrepresented in SMD swimmers under both additive and I-allele dominant models (permutation test p = 0.003 and p = 0.0005, respectively). ACE I/D was also associated with swimmer status in East Asians. In this group, however, the I-allele was overrepresented in the SD swimmer group (permutation test p = 0.041 and p = 0.0098 under the additive and the D-allele-dominant models, respectively). ACTN3 R577X was not significantly associated with swimmer status in either Caucasians or East Asians. CONCLUSIONS: ACE I/D associations were observed in these elite swimmer cohorts, with different risk alleles responsible for the associations in swimmers of different ethnicities. The functional ACTN3 R577X polymorphism did not show any significant association with elite swimmer status, despite numerous previous reports of associations with 'power/sprint' performance in other sports.Additional co-authors: Jason Gulbin, Viktor A. Rogozkin, Ildus I. Ahmetov, Nan Yang, Kathryn N. North, Saraslanidis Ploutarhos, Hugh E. Montgomery, Mark E.S. Bailey, and Yannis P. Pitsiladi

Muscle metabolism and performance improvement after two training programmes of sprint running differing in rest interval duration

Repeated-sprint training often involves short sprints separated by inadequate recovery intervals. The effects of interval duration on metabolic and performance parameters are unclear. We compared the effects of two training programmes, differing in rest interval duration, on muscle (vastus lateralis) metabolism and sprint performance. Sixteen men trained three times a week for 8 weeks, each training session comprising 2-3 sets of two 80-m sprints. Sprints were separated by 10 s (n = 8) or 1 min (n = 8). Both training programmes improved performance in the 100-, 200-, and 300-m sprints, but the improvement was greater in the 10-s group during the final 100 m of the 200- and 300-m runs. Independent of interval duration, training mitigated the drop of muscle ATP after two 80-m sprints. The drop in phosphocreatine and the increases in glucose-6-phosphate and fructose-6-phosphate after two 80-m sprints were greater in the 10-s group. In conclusion, training with a limited number of repeated short sprints (≤10 s) may be more effective in improving speed maintenance in 200- and 300-m runs when performed with a 1:1 rather than a 1:6 exercise-to-rest ratio. This may be due to a greater activation of glycolysis caused, in part, by the limited resynthesis of phosphocreatine during the very short rest interval. © 2011 Taylor &amp; Francis

1H NMR study on the short-and long-term impact of two training programs of sprint running on the metabolic fingerprint of human serum

Metabonomics is an established strategy in the exploration of the effects of various stimuli on the metabolic fingerprint of biofluids. Here, we present an application of 1H NMRbased metabonomics on the field of exercise biochemistry. Fourteen men were assigned to either of two training programs, which lasted 8 weeks and involved sets of 80-m maximal runs separated by either 10 s or 1 min of rest. Analysis of pre-and postexercise serum samples, both at the beginning and end of training, by 1H NMR spectroscopy and subsequent multivariate statistical techniques revealed alterations in the levels of 18 metabolites. Validated O-PLS models could classify the samples in regard to exercise, the separation being mainly due to lactate, pyruvate, alanine, leucine, valine, isoleucine, arginine/lysine, glycoprotein acetyls, and an unidentified metabolite resonating at 8.17 ppm. Samples were also classified safely with respect to training, the separation being mainly due to lactate, pyruvate, methylguanidine, citrate, glucose, valine, taurine, trimethylamine N-oxide, choline-containing compounds, histidines, acetoacetate/acetone, glycoprotein acetyls, and lipids. Samples could not be classified according to the duration of the rest interval between sprints. Our findings underline the power of metabonomics to offer new insights into the short-and long-term impact of exercise on metabolism. © 2012 American Chemical Society

1H NMR-based metabonomic investigation of the effect of two different exercise sessions on the metabolic fingerprint of human urine

Physical exercise modifies animal metabolism profoundly. Until recently, biochemical investigations related to exercise focused on a small number of biomolecules. In the present study, we used a holistic analytical approach to investigate changes in the human urine metabolome elicited by two exercise sessions differing in the duration of the rest interval between repeated efforts. Twelve men performed three sets of two 80 m maximal runs separated by either 10 s or 1 min of rest. Analysis of pre- and postexercise urine samples by 1H NMR spectroscopy and subsequent multivariate statistical analysis revealed alterations in the levels of 22 metabolites. Urine samples were safely classified according to exercise protocol even when applying unsupervised methods of statistical analysis. Separation of pre- from postexercise samples was mainly due to lactate, pyruvate, hypoxanthine, compounds of the Krebs cycle, amino acids, and products of branched-chain amino acid (BCAA) catabolism. Separation of the two rest intervals was mainly due to lactate, pyruvate, alanine, compounds of the Krebs cycle, and 2-oxoacids of BCAA, all of which increased more with the shorter interval. Metabonomics provides a powerful methodology to gain insight in metabolic changes induced by specific training protocols and may thus advance our knowledge of exercise biochemistry. © 2010 American Chemical Society