Gil Rodas

A SHORT TRAINING PROGRAMME FOR THE RAPID IMPROVEMENT OF BOTH AEROBIC AND ANAEROBIC METABOLISM

Abstract The aim of this study was to evaluate the changes in aerobic and anaerobic metabolism produced by a newly devised short training programme. Five young male volunteers trained daily for 2 weeks on a cycle ergometer. Sessions consisted of 15-s all-out repetitions with 45-s rest periods, plus 30-s all-out repetitions with 12-min rest periods. The number of repetitions was gradually increased up to a maximum of seven. Biopsy samples of the vastus lateralis muscle were taken before and after training. Performance changes were evaluated by two tests, a 30-s all-out test and a maximal progressive test. Significant increases in phosphocreatine (31%) and glycogen (32%) were found at the end of training. In addition, a significant increase was observed in the muscle activity of creatine kinase (44%), phosphofructokinase (106%), lactate dehydrogenase (45%), 3-hydroxy-acyl-CoA dehydrogenase (60%) and citrate synthase (38%). After training, performance of the 30-s all-out test did not increase significantly, while in the maximal progressive test, the maximum oxygen consumption increased from mean (SD) 57.3 (2.6) ml · min−1 · kg−1 to 63.8 (3.0) ml · min−1 · kg−1, and the maximum load from 300 (11) W to 330 (21) W; all changes were significant. In conclusion, this new protocol, which utilises short durations, high loads and long recovery periods, seems to be an effective programme for improving the enzymatic activities of the energetic pathways in a short period of time.

Classification and grading of muscle injuries: a narrative review

A limitation to the accurate study of muscle injuries and their management has been the lack of a uniform approach to the categorisation and grading of muscle injuries. The goal of this narrative review was to provide a framework from which to understand the historical progression of the classification and grading of muscle injuries. We reviewed the classification and grading of muscle injuries in the literature to critically illustrate the strengths, weaknesses, contradictions or controversies. A retrospective, citation-based methodology was applied to search for English language literature which evaluated or utilised a novel muscle classification or grading system. While there is an abundance of literature classifying and grading muscle injuries, it is predominantly expert opinion, and there remains little evidence relating any of the clinical or radiological features to an established pathology or clinical outcome. While the categorical grading of injury severity may have been a reasonable solution to a clinical challenge identified in the middle of the 20th century, it is time to recognise the complexity of the injury, cease trying to oversimplify it and to develop appropriately powered research projects to answer important questions.

Single nucleotide polymorphisms associated with non-contact soft tissue injuries in elite professional soccer players: influence on degree of injury and recovery time

BackgroundThe biological mechanisms involved in non-contact musculoskeletal soft tissue injuries (NCMSTI) are poorly understood. Genetic risk factors may be associated with susceptibility to injuries, and may exert marked influence on recovery times.MethodsData on type and degree of injury and recovery time were collected in 73 male professional soccer players (43 White, 11 Black Africans and 19 Hispanics) who suffered total of 242 injuries (203 muscle, 24 ligament, and 15 tendon injuries). One single nucleotide polymorphism (SNPs) in the following genes were analyzed: Elastin (ELN); Titin (TTN); SRY-related HMG-box (SOX15); Insulin-like growth factor 2 (IGF2); Chemokine, CC motif, ligand 2 (CCL2); Collagen type 1 alpha 1(COL1A1); Collagen type 5 alpha 1 (COL5A1), and Tenascin C (TNC).ResultsThere was evidence of a statistically significant association between the degree of injury and the IGF2 genotype (P = 0.034). In addition, there was evidence of a statistically significant association between the degree of muscle injury and CCL2 (P = 0.026) Finally, there was evidence of a statistically significant association between ELN and degree of injury (p = 0.009) and recovery time (P = 0.043). There was no evidence of a statistically significant association between any of the genes studied and degree of injury or recovery time for tendon injuries.ConclusionSNPs in the IGF2, CCL2, and ELN genes may be associated to the degree and recovery time of NCMSTI.

Comparison of omega wave system and polar S810i to detect R-R intervals at rest

The present study was performed to compare R-R interval data and heart rate variability indices obtained from the Polar S810i and the Omega Wave Sport System for a total of 96 adults in a supine position. Data were simultaneously recorded with the Polar S810i and the Omega Wave Sport System and processed by unique software. Bland-Altman analysis for the R-R intervals shows minimal bias for free and paced breathing. No significant differences were observed for heart rate variability indices derived from the signal from both devices, except for the power of the high frequency band and the acceleration changes index during either free or paced breathing. Coefficients of correlations were all above 0.96. These data suggest that both systems are valid to record R-R interval signals and to obtain a valid analysis of heart rate variability. However, Omega Wave Sport System enables data to be collected without any artifacts making the analysis of heart rate variability easier than the analysis of Polar S810i. Nevertheless, Polar S810i continues to be more practical in clinical and applied situations due to the affordability of the device.

Effect of prior ingestion of glucose or fructose on the performance of exercise of intermediate duration

The metabolic responses induced by the ingestion of a beverage containing glucose (G), fructose (F) or placebo (W) 30 min before exercise of high intensity and intermediate duration have been investigated; in these conditions the energy processes are mostly dependent on aerobic reactions. A group of 11 male recreational sportsmen ran on a treadmill, at an intensity corresponding to 82% of peak oxygen consumption, until exhaustion on three different occasions (after ingestion of a beverage containing 75 g of G, 75 g of F or W). Plasma glucose, insulin, and lactic acid concentrations were determined just prior to the ingestion of the beverages, 30 min afterwards and 10 and 30 min after completion of the exercise. The mean endurance time was 644 (SD 261) s after the ingestion of G, 611 (SD 227) s after the ingestion of F and 584 (SD 189) s after the ingestion of the W (P < 0.05 between G and W). No differences in the oxygen uptake, respiratory quotient or lactate concentrations between the three trials were observed. Both plasma glucose and insulin concentrations determined in samples obtained immediately before the onset of exercise were higher when G was ingested than when F (P < 0.05 andP < 0.05, respectively) or W (P < 0.001 and P < 0.005, respectively) were ingested. These findings would suggest that the ingestion of G prior to an effort of intermediate duration may improve physical performance.

Fast and slow myosins as markers of muscle injury

Objective: The diagnosis of muscular lesions suffered by athletes is usually made by clinical criteria combined with imaging of the lesion (ultrasonography and/or magnetic resonance) and blood tests to detect the presence of non-specific muscle markers. This study was undertaken to evaluate injury to fast and slow-twitch fibres using specific muscle markers for these fibres. Methods: Blood samples were obtained from 51 non-sports people and 38 sportsmen with skeletal muscle injury. Western blood analysis was performed to determine fast and slow myosin and creatine kinase (CK) levels. Skeletal muscle damage was diagnosed by physical examination, ultrasonography and magnetic resonance and biochemical markers. Results: The imaging tests were found to be excellent for detecting and confirming grade II and III lesions. However, grade I lesions were often unconfirmed by these techniques. Grade I lesions have higher levels of fast myosin than slow myosin with a very small increase in CK levels. Grade II and III lesions have high values of both fast and slow myosin. Conclusions: The evaluation of fast and slow myosin in the blood 48 h after the lesion occurs is a useful aid for the detection of type I lesions in particular, since fast myosin is an exclusive skeletal muscle marker. The correct diagnosis of grade I lesions can prevent progression of the injury in athletes undergoing continual training sessions and competitions, thus aiding sports physicians in their decision making.

Hamstring Muscle Injuries, a Rehabilitation Protocol Purpose

Context: Hamstring acute muscle injuries are prevalent in several sports including AFL football (Australian Football League), sprinting and soccer, and are often associated with prolonged time away from sport. Evidence Acquisition: In response to this, research into prevention and management of hamstring injury has increased, but epidemiological data shows no decline in injury and re-injury rates, suggesting that rehabilitation programs and return to play (RTP) criteria have to be improved. There continues to be a lack of consensus regarding how to assess performance, recovery and readiness to RTP, following hamstring strain injury. Results: The aim of this paper was to propose rehabilitation protocol for hamstring muscle injuries based on current basic science and research knowledge regarding injury demographics and management options. Conclusions: Criteria-based (subjective and objective) progression through the rehabilitation program will be outlined along with exercises for each phase, from initial injury to RTP.

Facial Video-Based Photoplethysmography to Detect HRV at Rest.

Our aim is to demonstrate the usefulness of photoplethysmography (PPG) for analyzing heart rate variability (HRV) using a standard 5-min test at rest with paced breathing, comparing the results with real RR intervals and testing supine and sitting positions. Simultaneous recordings of R-R intervals were conducted with a Polar system and a non-contact PPG, based on facial video recording on 20 individuals. Data analysis and editing were performed with individually designated software for each instrument. Agreement on HRV parameters was assessed with concordance correlations, effect size from ANOVA and Bland and Altman plots. For supine position, differences between video and Polar systems showed a small effect size in most HRV parameters. For sitting position, these differences showed a moderate effect size in most HRV parameters. A new procedure, based on the pixels that contained more heart beat information, is proposed for improving the signal-to-noise ratio in the PPG video signal. Results were acceptable in both positions but better in the supine position. Our approach could be relevant for applications that require monitoring of stress or cardio-respiratory health, such as effort/recuperation states in sports.

Intratendinous gouty tophus mimics patellar tendonitis in an athlete

We describe the imaging and pathologic features of a case of intratendinous patellar gouty tophus incidentally discovered in a patient with knee pain. The possibility of intratendinous gouty tophus must be kept in mind by sports physicians, especially in the management of patellar tendinopathy in athletes. It may be associated with other injuries, such as enthesopathies or partial tendon tears.

Heritability of running economy: a study made on twin brothers.

Abstract Running economy (RE), defined as the steady-state of oxygen uptake (V˙O2) for a given running velocity, is a factor of sports performance the genetic component of which has seldom been reported to date. We studied this component using a heritability index (HI) in a group of 32 male twins, 8 monozygotic (MZ) and 8 dizygotic (DZ) pairs, all sportsmen with similar perinatal and environmental backgrounds. Zygocity was determined by the identity of erythrocytic antigenic, protein and enzymatic polymorphism, and human leucocyte antigen serologic types between co-twins. The subjects exercised twice on a treadmill, once until exhaustion and again at submaximal intensities. Pulmonary gas exchange was measured continuously using an automatic analyser system during both tests. Blood samples were obtained during the recovery period to determine lactate concentrations. No significant differences were observed between MZ and DZ, in respect of RE at any speed or in maximal V˙O2 relative to body mass. Nevertheless, significant HI (P < 0.05) was found in maximal lactate concentrations (HI = 0.75) and in respiratory equivalent for oxygen at two speeds, 7 km · h−1 (HI = 0.71) and 8 km · h−1 (HI = 0.79), differences which probably suggest that there are differences in RE. In conclusion, we did not detect a genetic component in RE or in maximal oxygen uptake, but a genetic component for markers of anaerobic metabolism was present.