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The purpose of this study was to present and biomechanically evaluate several variations of the Nordic hamstring exercise (NHE), achieved by altering the slope of the lower leg support and by asumming different hip flexion angles. Electromyographic and 2D kinematic measurements were conducted to analyse muscle activity (biceps femoris, semitendinosus, gluteus maximus, erector spine and lateral head of the gastrocnemius), knee and hip joint torques during 6 variations of NHE. The study involved 18 adults (24.9 ± 3.7 years) with previous experience in resistance training, but with little or no experience with NHE. Increasing the slope of the lower leg support from 0° (standard NHE) to 20° and 40° enabled the participants to perform the exercise through a larger range of motion, while achieving similar peak knee and hip torques. Instructions for increased hip flexion from 0° (standard NHE) to 25°, 50° and 75° resulted in greater peak knee and hip torque, although the participants were not able to maintain the hip angle at 50° nor 75°. Muscle activity decreased or remained similar in all modified variations compared to the standard NHE for all measured muscles. Our results suggest that using the presented variations of NHE might contribute to optimization of hamstring injury prevention and rehabilitation programs, by providing appropriate difficulty for the individual's strength level and also allow eccentric strengthening at longer hamstring lengths., Competing Interests: NŠ and GM were employed by commercial companies, S2P, Ltd. and Motus Melior, Ltd. The companies did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

The aim of the present work was to examine if hydrogen peroxide treatment of sugar beet fibre that aimed at improving its physicochemical properties would impair its antioxidant potential. Three different sugar beet fibres were obtained from sugar beet - non-treated fibre (NTF) from sugar beet cossettes extracted with sulphurous acid, treated fibre (TF) from NTF treated with hydrogen peroxide in alkaline solution and commercially available Fibrex(®) . The antioxidant activity of extractable and non-extractable fibre fractions in ethanol/water mixture (80:20, v/v) of three fibre samples was estimated. Non-extractable fractions obtained after alkaline treatment of investigated fibres were much higher in phenolic compounds and possessed higher antioxidant potential than extractable fractions. Ferulic acid was proven to be the dominant phenolic acid. Regarding both extractable and non-extractable fractions, Fibrex(®) had the highest antioxidant activity in chemical tests, while NTF was superior in comparison with TF. Based on the results of Caco-2 cells-based test, all non-extractable fractions possessed potential for reactive oxygen species inhibition. Regarding the extractable fractions, only the TF manifested this effect.Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

No previous study had applied the modified Wingate rowing test to young athletes (i.e. children and adolescents). The aims of this study were to evaluate the trial-to-trial reliability of a rowing-modified Wingate test in a group of 12-14-year-old rowers (n=98) and to compare anaerobic power values among the 12-, 13-, and 14-year-old rowers after accounting for differences in physical maturity and body size. Each subject performed two "all-out" 30-s trials on a Concept II rowing ergometer. The trials were separated by a 15-min active recovery period, which included walking and stretching and ensured the participants' full recovery. The test proved to be highly reliable, with coefficients of variations of 2.4 and 2.9% (CI=2.1-3.4%) and intraclass correlation coefficients of 0.994 and 0.996 (CI=0.991-0.997) for mean power and peak power, respectively. The ANCOVA analyses accounting for differences in body size and level of physical maturity (assessed using indices of pubic hair) and the Bonferroni post hoc tests identified the 14-year-olds as having significantly greater adjusted mean power and peak power values (P<0.01) than the other two age groups, while the differences between the 12- and 13-year-olds in terms of mean power and peak power were not significant. Our findings indicate (1) that the rowing-modified Wingate test may be reliably used for the assessment of specific anaerobic performance in 12-14-year-old rowers and (2) that factors other than physical maturity and body size are partly responsible for the increase in anaerobic power during growth.