Patrik Drid

Short-term isokinetic training versus isotonic training: effects on asymmetry in strength of thigh muscles.

Short-Term Isokinetic Training Versus Isotonic Training: Effects on Asymmetry in Strength of Thigh Muscles The aim of this study was to investigate the effects of two training protocols on the isokinetic performance of athletes. The study was conducted in 38 athletes, (age 23.3 ± 3.6 years) participating in national level leagues of different sports, whose initial concentric hamstrings-to-quadriceps (conH/Q) torque ratio was lower than 0.5. During seasonal testing, an isokinetic measurement of knee extensors and flexors was performed at 60º/s. The athletes were divided into two groups. Nineteen athletes performed the isokinetic training protocol (IT) while the second group of 19 athletes followed the isotonic training protocol (RT). Both protocols lasted 4 weeks. After completing the training protocols, both groups underwent a final isokinetic testing. The isokinetic data revealed significant increases after training in measures of peak torque in both extensor and flexor muscle groups, in both the IT and RT study groups (p < 0.05). There were significant increases (p< 0.05) in conH/Q ratio in both groups after the implemented protocols, but greater in IT group. Consequently, applied IT protocol induced changes in working muscles, thereby restoring detected asymmetry to an acceptable balance more efficiently compared to RT protocol.

Guanidinoacetic acid versus creatine for improved brain and muscle creatine levels: a superiority pilot trial in healthy men.

In this randomized, double-blind, crossover trial, we evaluated whether 4-week supplementation with guanidinoacetic acid (GAA) is superior to creatine in facilitating creatine levels in healthy men (n = 5). GAA (3.0 g/day) resulted in a more powerful rise (up to 16.2%) in tissue creatine levels in vastus medialis muscle, middle-cerebellar peduncle, and paracentral grey matter, as compared with creatine (P < 0.05). These results indicate that GAA as a preferred alternative to creatine for improved bioenergetics in energy-demanding tissues.

Fitness and Anthropometric Profiles of International vs. National Judo Medalists in Half-Heavyweight Category

Abstract Drid, P, Casals, C, Mekic, A, Radjo, I, Stojanovic, M, and Ostojic, SM. Fitness and anthropometric profiles of international vs. national judo medalists in half-heavyweight category. J Strength Cond Res 29(8): 2115–2121, 2015—The aim of the study was to determine the anthropometric and fitness profiles of European half-heavyweight judokas by success in competition. For this purpose, we compared 5 international medalists (elite) with 5 national medalists (subelite). All male judokas won at least 1 medal in the half-heavyweight category during the previous 2 years. The testing in this cross-sectional study was performed during 4 days. All subjects underwent anthropometric assessment with body mass, height, skinfold, and limb circumference measures, and the body fat percentage was estimated by manual bioimpedance. The physical fitness evaluation consisted in peak torques for thigh and shoulder muscles, handgrip strength, high and long jumps, medicine ball throw, pull-ups, deadlift, bench press, deep squat, V[Combining Dot Above]O2max, Max Power, and Tokui Waza tests. The statistical analysis by the Students t test showed significant differences for forearm and upper-arm circumferences, peak torques, pull-ups, bench press, deadlift, deep squat, V[Combining Dot Above]O2max, Max Power, and Tokui Waza tests. Our results showed that elite judokas have a superior fitness profile than subelite athletes from the half-heavyweight category. Moreover, elite judokas seem to have a higher arm muscle mass than subelite athletes but a similar body fat percentage. This study could be of interest for judo coaches with athletes competing in the half-heavyweight category, as some tests that discriminate by judo success for this specific weight category are described. Few studies analyze anthropometric and fitness profiles in half-heavyweight male judokas, so additionally our results can be used as a reference for coaches, athletes, and scientists.

Guanidinoacetic acid increases skeletal muscle creatine stores in healthy men

Guanidinoacetic acid (GAA; also known as glycocyamine, betacyamine, or guanidinoacetate) is an experimental dietary additive that enhances serum creatine bioavailability and affects blood-derived metabolic markers of methylation in humans [1]. Because creatine is an important compound in cellular bioenergetics [2], consumption of GAA has been recognized as an effective investigational intervention to facilitate creatine-mediated energy provision in health and disease [3]. At the same time, the methylation of GAA to form creatine consumes w40% of available methyl groups, potentially depleting the sources of methyl groups in the body, including methionine, folate, betaine, and choline [4]. However, to our knowledge, no human study so far has evaluated the effects of GAA consumption on creatine bioavailability and/or use of methyl groups in tissues with high-energy requirements, such as skeletal muscle or brain. In this pilot study, we evaluated the effects of 4-wk GAA supplementation on total creatine and choline levels in human skeletal muscle of healthy men. Four healthy young and physically active men (age 25 3 y, body mass index 24.3 1.6 kg/m2, physical activity 15 2 h/wk) were assigned to receive 3 g/d of oral GAA for 4 wk in this open-label, repeated-measure pilot study. Sample size (N 1⁄4 4) was in accordance with the power analysis (effect size 1⁄4 0.9, a error probability 1⁄4 0.05, power 1⁄4 0.95) for the primary outcome measure. Our primary outcome measure was the change in total creatine levels in the right vastus medialis muscle assessed at baseline and at 4 wk. Secondary outcome measures were total choline levels, intramyocellular and extramyocellular triacylglycerol contents, and muscle water. In vivo metabolite concentrations were determined by 1.5 T magnetic resonance spectroscopy using a four-element body matrix receiver coil (Siemens Avanto Tim, Erlangen, Germany) and calculated using the muscle water signal as an internal intensity reference [5]. Participants were obliged to maintain their usual diets (apart from the intervention) and physical activity levels during the study. All participants gave written informed consent before

Supplementation with Guanidinoacetic Acid in Women with Chronic Fatigue Syndrome

A variety of dietary interventions has been used in the management of chronic fatigue syndrome (CFS), yet no therapeutic modality has demonstrated conclusive positive results in terms of effectiveness. The main aim of this study was to evaluate the effects of orally administered guanidinoacetic acid (GAA) on multidimensional fatigue inventory (MFI), musculoskeletal soreness, health-related quality of life, exercise performance, screening laboratory studies, and the occurrence of adverse events in women with CFS. Twenty-one women (age 39.3 ± 8.8 years, weight 62.8 ± 8.5 kg, height 169.5 ± 5.8 cm) who fulfilled the 1994 Centers for Disease Control and Prevention criteria for CFS were randomized in a double-blind, cross-over design, from 1 September 2014 through 31 May 2015, to receive either GAA (2.4 grams per day) or placebo (cellulose) by oral administration for three months, with a two-month wash-out period. No effects of intervention were found for the primary efficacy outcome (MFI score for general fatigue), and musculoskeletal pain at rest and during activity. After three months of intervention, participants receiving GAA significantly increased muscular creatine levels compared with the placebo group (36.3% vs. 2.4%; p < 0.01). Furthermore, changes from baseline in muscular strength and aerobic power were significantly greater in the GAA group compared with placebo (p < 0.05). Results from this study indicated that supplemental GAA can positively affect creatine metabolism and work capacity in women with CFS, yet GAA had no effect on main clinical outcomes, such as general fatigue and musculoskeletal soreness.

A single session of exhaustive exercise markedly decreases circulating levels of guanidinoacetic acid in healthy men and women

We evaluated the effects of exercise on circulating concentrations of guanidinoacetic acid (GAA) and creatine in 23 healthy volunteers subjected to running to exhaustion and free-weight bench-press to volitional failure. Blood was taken before and following each exercise session. Running induced a significant decrease in serum GAA by 20.1% (P < 0.001), while free-weight exercise reduced GAA by 11.7% (P < 0.001), suggesting the possible use of serum GAA as a novel biomarker of exhaustion.

Aerobic capacity of handball players with hearing impairment

Aerobic capacity of handball players with hearing impairment Study aim: To determine the aerobic capacity of handball players with hearing impairment as compared with the healthy ones. Material and methods: Two groups of subjects took part in this study: healthy national handball players (NHB; n = 15) aged 18 - 33 years and international handball players with hearing impairment (IHB; n = 13), winners of European Deaf-Mute Championships in 2008 (Belgrade, Serbia) and second place in Deaflympic games in 2009 (Taipei, Taiwan), aged 21 - 48 years. Cosmed T-170 treadmill (FSPE1 protocol) and a breath-by-breath gas analyser were used to determine the following indices of aerobic capacity: maximal heart rate (HRmax), ‡O2max, oxygen pulse, lung ventilation, tidal volume, maximum speed. Results: Players from the IHB group attained significantly (p<0.05 - 0.01) lower values of oxygen pulse and maximum speed (by 12%), heart rate 1 min post-exercise (by 6%), lung ventilation (by 11%) and tidal volume (by 14%) compared with NHB group. IHB players had also twice lower weekly training volume. On the other hand, no significant between-group difference was found fo the relative O2max. Conclusion: The lower results attained by handball players with impaired hearing compared with the healthy ones could be attributed to lower training volume per week. Thus, an increase in the training volume for the disabled players would be recommendable.

Does Dietary Provision of Guanidinoacetic Acid Induce Global DNA Hypomethylation in Healthy Men and Women

Background/Aims: Guanidinoacetic acid (GAA) is an experimental dietary additive and has been reported to induce methyl depletion when provided by the diet. However, no study evaluated whether supplemental GAA affects DNA methylation, a critical epigenetic process for genome regulation. Methods: In this open-label, repeated-measure interventional trial, we evaluated the impact of 12 weeks of GAA supplementation on global DNA methylation in 14 healthy participants (8 women and 6 men, age 22.2 ± 2.3 years, body mass index 24.8 ± 5.7). Results: Dietary provision of GAA had no effect on global DNA methylation, with 5-methylcytosine (m5C) nonsignificantly increased by 13.4% at postadministration when averaged across participants (95% confidence interval –5.5 to 32.3; p = 0.26). Notable DNA hypomethylation (corresponding to a 5% drop in m5C) was found in 3 of 14 participants at follow-up. Conclusion: Global DNA methylation seems to be unaltered by dietary provision of 3 g of GAA per day for 12 weeks in healthy men and women.

Differences in anthropometric, motoric and cognitive abilities between athletically trained and untrained girls

Summary Study aim: the aim of the study was to identify differences between athletically trained and untrained subjects with respect to body composition, motor and cognitive abilities. Materials and methods: three groups of girls aged 12 to 14 years old participated in the study: young judokas (n = 42), volleyball players (n = 54) and their untrained peers (n = 54). Variables of interest were assessed through eight motor tests, nine anthropometric variables and the RSPM. Results: this study showed differences in some anthropometric characteristics and almost all motoric abilities between trained girls and untrained girls (p < 0.05), indicating that well-programmed activity can positively influence these characteristics and abilities. In addition, group of volleyball players presented significantly better results in cognitive abilities (p < 0.01), indicating a need for intelligence in complex sports like volleyball. Conclusions: generally, the trained groups of athletes possessed better coordination and strength than their untrained counterparts.