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Inha University Introduction Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are cholesterol-lowering drugs widely used in the treatment of cardiovascular disease (Koh et al., 2011). However, statins also cause adverse side effects in skeletal muscle ranging from fatigue to fatal rhabdomyolysis. Recently, we found that long-term (48 h) treatment of simvastatin induced cell death due to impaired mitochondrial respiration and oxidative stress leading to mitochondrial apoptotic signaling in primary human skeletal muscle cells (Kwak et al., 2012). The purpose of this study was to determine the effects of short-term (24 h) simvastatin treatment on mitochondrial respiration, H2O2 emission, apoptotic signaling, and morphological changes in differentiated human skeletal myotubes. Methods Primary myoblasts isolated from vastus lateralis in lean male (N=6) were grown and differentiated to myotubes (6 days), and then incubated in differentiation media (0.1% DMSO) with or without simvastatin (5 μM) for an additional 24 hours. The myotubes were harvested and permeabilized by digitonin (3 μg/106 cells) for determination of mitochondrial respiration and H2O2 emission. In addition, markers of apoptosis (cell numbers, Bax and Bcl-2) and MnSOD protein levels were measured in primary human skeletal myotubes. Results After 24 hour incubation, simvastatin treated myotubes (STM) were not changed in morphology and total cell numbers compared with control.
stimulated, state 2) was similar between STM and control. However, maximal ADP-stimulated (state 3) oxygen consumption rate showed lower trends (P=0.08) in STM supported by PCM. Mitochondrial H2O2 emission rate was not affected by short-term STM compared with control. Similarly, 24 h treatment of simvastatin did not have significant effects on the protein levels of Bax, Bcl-2, and MnSOD in primary human skeletal myotubes. Discussion Long-term (48 h) treatment of simvastatin impaired maximal ADP-stimulated mitochondrial respiration, induced mitochondrial oxidative stress, and increased mitochondrial-mediated apoptotic signaling and cell death in primary human skeletal myotubes (Kwak et al., 2012). However, these data demonstrated that short-term (24 h) treatment of simvastatin did not induce atrophy and cell death that is primarily associated with the impairment of mitochondrial function and the activation of mitochondrial apoptosis in primary human skeletal myotubes. References Koh K, Sakuma, I, Quon, M. (2011). Atherosclerosis, 215, 1–8. Kwak H, Thalacker-Mercer A, Anderson E, Lin C, Kane D, Cortright R, Bamman M, and Neufer P. (2012). Free Radic Biol Med, 52, 198-207.
LACK OF A PHYSIOLOGICAL ROLE FOR ERYTHROPOIETIN IN HUMAN SKELETAL MUSCLEChristensen, B.1,2, Nellemann, B.1, Thorsen, K.4, Pedersen, S.B.1, Ørnstrup, M.J.1, Jørgensen, J.O.L.1, Jessen, N.3,4 1,3,4 Aarhus University Hospital, 2 Aarhus University Background: Erythropoietin (Epo) is considered a pleiotropic hormone, but the presence of Epo receptor (Epo-R) in human skeletal muscle tissue has been debated, mainly due to a lack of specificity of the Epo-R antibodies used to identify Epo-R’s in skeletal muscle tissue (1). In addition, we have previously shown no activation of the signalling pathways downstream of the Epo-R (2), further questioning a physiological role for Epo in human skeletal muscle tissue. Aim: The aim of the current study was to thoroughly evaluate Epo’s prolonged effects on skeletal muscle; large-scale analysis of mRNA expression was performed by gene array analysis. Furthermore, a new and highly sensitive antibody evaluated Epo-R expression in human skeletal muscle tissue. Methods: Human skeletal muscle biopsies from two clinical studies were used to investigate; 1) gene expression in relation to prolonged treatment with rHuEpo (study A) evaluated by gene array, 2) Epo-R presence determined by western blotting using a new and sensitive antibody (A82, Amgen)(study B). In study A, nine healthy men received one weekly s.c. injection with rHuEpo for 10 weeks (Darbepoietin-α, Aranesp, Amgen); biopsies were collected before and after treatment. In study B, biopsies were collected from ten healthy young men under basal conditions. Results: When correcting for multiple testing, no significant changes in skeletal muscle gene expressions after a prolonged period of rHuEpo treatment were found. Therefore, Epo-R expression was evaluated. Unlike previous studies, with a new and sensitive antibody, A82, it was not possible to identify Epo-R´s in human skeletal muscle tissue. Conclusion: In conclusion, prolonged rHuEpo treatment does not affect gene expression in human skeletal muscle, and a physiological role of Epo-R in skeletal muscle is unlikely. (1) Elliott S, Busse L, Bass MB, Lu H, Sarosi I, Sinclair AM, Spahr C, Um M, Van G, and Begley CG. Anti-Epo receptor antibodies do not predict Epo receptor expression. Blood 107: 1892-1895, 2006. (2) Christensen B, Lundby C, Jessen N, Nielsen TS, Vestergaard PF, Moller N, Pilegaard H, Pedersen SB, Kopchick JJ, and Jorgensen JO. Evaluation of functional erythropoietin receptor status in skeletal muscle in vivo: acute and prolonged studies in healthy human subjects. PloS one 7: e31857, 2012.
08:30 - 10:00 Oral presentations OP-PM10 Health and Fitness [HF] 6
EFFECT OF “FUNCTIONAL FOOD” SUPPLEMENTATION ON MUSCLE GROWTH AND STRENGTH INDUCED BY 12 WEEKS
OF RESISTANCE EXERCISE IN ELDERLY MENHetlelid, K.J., Bjørnsen, T., Salvesen, S., Berntsen, S., Stea, T.H., Lohne-Seiler, H., Paulsen, G.
University of Agder Introduction Lack of dietary protein and micronutrients is often found amongst elderly. The aim of the present study was to investigate the effect of a mixed supplementation on muscle growth and strength after 12 weeks of strength training in elderly men. METHODS Thirtythree elderly males (60 – 81 yrs old) were included to either a supplemented group (N=16) or a placebo group (N=17) in a double blinded randomized placebo controlled trial. Muscle growth was assessed as changes in lean mass with DEXA and thickness of rectus femoris, vastus lateralis and arm flexors (brachialis and biceps brachii) with ultrasound imaging. Strength was measured as 1RM in leg press, knee extension and scott curl. A four day validated 18-page pre-coded food diary was completed. The supplementation was based on natural antioxidant-rich pomegranate juice with 22 g of carbohydrates, enriched with marine omega-3 fatty acids (900 mg), 15 μg vitamin D and 9 g whey protein isolate + 2 g of leucine and were administrated twice daily. All participants conducted resistance exercise 3 times a week, following an undulating periodized program: 2/wk 8-10RM (1 min inter-set rest periods), 1/wk between 3-5RM (2 min rest) or 13-15RM (45 sec rest). The load was weekly adjusted, and the volume increased progressively throughout the 12 weeks of resistance exercise. Data was analyzed using non-parametric tests. RESULTS The supplemented group (mean±SD, 112g±39) had significantly higher protein intake at baseline compared to the placebo group (86g±20)(p=0.02), but not post. 1RM increased in the range of 15-20% in supplemented and placebo groups during 12 weeks of resistance exercise (p0.001); no group differences were identified. Lean body mass increased for both the supplemented group (2.2 kg (median with 95% confidence intervals) (0.9-2.9)) and the placebo group (2.2 kg (1.5after 12 weeks of resistance training (p0.01). However, the rectus femoris thickness increased more in the placebo group (16.2% (12.8-24.1) than the supplemented group, (11% (4.1-17)) (p0.05), while no significant differences between group were found for arm flexors and vastus lateralis thickness. DISCUSSION A mixed supplement with omega-3 fatty acids and whey protein did not have any additional effects on the adaptations to resistance exercise in elderly men. This might be due to an already sufficient intake of such nutrients, or insufficient levels of proteins in the supplementation to stimulate further muscle growth. Note: The Smartfish® company partly financed this study.
A SIMPLE 45 SECOND SQUAT TEST CAN ACCURATELY PREDICT VO2MAX: PRELIMINARY RESULTSSartor, F., Bosio, A., Bonomi, A., Kubis, H.P.
Philips Research Introduction VO2max is an important parameter to determine the functional capacity of the cardio-respiratory system. Its direct determination via maximal exercise testing may result not always feasible to perform, in particular in subjects with increased risk of cardiovascular diseases. Thus we have validated a simple and short sub-maximal test which does not require any type of equipment other than a heart rate (HR) monitor and a metronome and can be performed by anybody with no lower limbs limitations. Methods Eight male cyclists (Age: 19 ± 2 yrs; Height: 177 ± 7 cm; Weight: 65.4 ± 4.5 kg; Body Fat %: 8.36 ± 2.00%) underwent a Ruffier-Dickson test. This consisted of resting supine for 5 min, then standing up, and once the HR was stable, performing 30 squats in 45 s following a metronome set at 80 bpm. Once the squatting exercise was completed the participants laid down supine to recover for 3 min. HR was recorded throughout.
After 3 min when HR ≤ initial resting HR the participants underwent a Vo2max test on the cycle ergometer. Body fat % was estimated via plicometry. Results The cyclists had a mean VO2max of 4.36 ± 0.44 L/min, 67.2 ± 6.2 mL/kg/min. Their VO2max significantly correlated with their height (r = 0.746, p = 0.03), and slope of HR increase during the squats (r = 0.705, p = 0.05). The best VO2max prediction via multiple linear regression showed high r = 0.977 and adjusted r2 = 0.892, and small inaccuracy, Standard Error of Estimate (SEE) = 0.145 L/min, SEE%= 3.3. Eq.1: VO2max (L/min) = -2.489 + (0.0436 * height (cm)) + (1.458 * Slope Sq HR) - (0.00234 * Recovery DeltaHR120 (bpm))
- (0.170 * Fat %). If body fat % via plicometry is not available VO2max can be still predicted accurately using Eq.2: VO2max (L/min) = -1.788 + (0.0317 * height (cm)) + (1.812 * Slope Sq HR) - (0.00834 * Recovery DeltaHR120 (bpm)); r = 0.812, adjusted r2 = 0.405, SEE = 0.340 L/min, SEE% = 7.8. Discussion We have developed a model (Eq.1), which can accurately (3% error) predict VO2max in young male athletes from a simple 45s squat test. Although body fat % increases the prediction accuracy, if not available the accuracy of an alternative model (Eq.2) (7.8% error) is still in line with other sub-maximal tests (e.g. 9% Astrand-Rhyming cycling test, 11.4% Ebbeling treadmill test, 8% McArdle step test). We are currently testing more sedentary individuals to see whether these results can be generalized. Although these are preliminary results on only 8 participants and the error might increase when a large sample is considered, this 45s squat test seems to be very promising.
ASSOCIATION BETWEEN MOTOR COMPETENCE AND PHYSICAL ACTIVITY. A LONGITUDINAL STUDY IN CHILDRENLopes, V.P., Sousa, J.F.D., Rodrigues, L.P.
Polytechnic Institute of Braganca Introduction: The aim of this study was to analyze the influence of motor competence on children’s physical activity levels (PA). Motor skills proficiency and coordination levels were studied as predictors of children’s PA levels during 4 years. Methods: This longitudinal study took place between 2009 and 2012, with a sample of 98 children. At the beginning of the study the sample was composed of 24 children with OP-PM49 Training and Testing [TT] 3 six years old, 40 children with seven years and 34 children with eight years, who were followed over 4 consecutive years, performing annual assessments of anthropometric variables, PA, motor coordination and fundamental motor skills. Pedometer was used as an objective instrument for assessing PA, test of Körperkoordination Test für Kinder (KTK) to assess motor coordination and test of Gross Motor Development (TGMD-2) to assess the fundamental movement skills, composed by objects control skills and locomotor skills. For data analysis we used the hierarchical or multilevel modeling, in order to determine the predictors of PA through five successive adjustment models. Results: The children’s PA levels significantly decreased over time. At baseline the girls had a PA level significantly lower than boys. The magnitude of the differences in PA levels between boys and girls has not changed significantly over the observations.
Motor coordination levels and proficiency in object control skill were not predictors of PA, whereas the proficiency in locomotor skills was the only significant predictor of PA. There were a large percentage of children who did not comply with the minimum recommendations in the number of daily steps and this situation tends to worsen with increasing age, especially in girls. Conclusions: The locomotor motor skills were a significant predictor of children’s PA levels along 4 years.
EXERCISE HYDRATION KNOWLEDGE OF SINGAPOREAN YOUTH COACHES AND PHYSICAL EDUCATION TEACHERSChia, M., Mukherjee, S., Huang, S.H.
National Institute of Education, Nanyang Technological University, Singapore Introduction Dehydration has deleterious effects on sport performance and contributes to heat-related illnesses. Singapore youth athletes are at a greater risk of dehydration-associated ailments due to the tropical climate, especially when training outdoors. Coaches and Physical Education (PE) teachers must possess adequate hydration knowledge to ensure optimal performance and sports safety in the youth athletes. The present study examines the exercise hydration knowledge of Singapore coaches and PE teachers. Methods 193 coaches (Beginning coaches n=129, certified coaches n=64) and 164 PE teachers (Beginning teachers n= 102, graduating teachers n=62) participated in the study. Participants completed a questionnaire based upon ACSM and NATA guidelines on fluid replacement for athletes (Casa et al. 2000; Sawka et al. 2007). The questionnaire consisted of pre-exercise, during-exercise and post-exercise hydration knowledge sections. Adequate hydration knowledge was accepted as a score of 80% and above (Ransone and Dunn-Bennett 1999).
Results 70.3% of participants were coaching youth athletes. Average knowledge scores were: beginning coaches (BC)-61.76±12.36%;