28 research outputs found
Untersuchung der Dosis-Wirkungsbeziehung von Isomaltulose
No full textHintergrund: Der Einfluss von Kohlenhydraten auf die Leistung im Ausdauersport ist schon sehr genau untersucht. Die Isomaltulose ist ein natürlich vorkommendes Disaccharid, das aus einem Glukose- und einem Fruktosemolekül besteht. Im Gegensatz zu Saccharose und Maltose wird sie im Dünndarm sehr langsam hydrolisiert. Der Anstieg in der Blutglukose und im Insulin verläuft daher um Vergleich zu anderen Sacchariden flacher. Für Glukose gibt es bereits eine Dosis-Wirkungsbeziehung mit einer maximal empfohlenen Menge von 90 g/h. Solche Daten sind für die Isomaltulose jedoch noch ausständig.
Zielsetzung: Ziel der vorliegenden Arbeit war es, die Dosis-Wirkungsbeziehung von Isomaltulose zu untersuchen. Die Untersuchung sollte anhand der Messung von verschiedenen Leistungsfaktoren während einer zweistündigen Dauerbelastung am Rad und einem abschließenden Zeitfahren erfolgen. Aus den Ergebnissen abgeleitet sollten am Ende Trainingsempfehlungen für die Dosierung von Isomaltulose gegeben werden können.
Methodik: Für die empirische Arbeit wurde eine doppelblinde, randomisierte Cross-Over Studie mit zwölf Ausdauersportlern durchgeführt.
Resultate und Schlussfolgerung: Für Isomaltulosekonzentrationen zwischen 20 und 60 g/h konnte keine Dosis-Wirkungsbeziehung nachgewiesen werden. Es gibt zwischen den Konzentrationen weder einen Unterscheid in der Effizienz noch in den physiologischen Parametern oder der Substratverwendung. Auch in der Leistung beim abschließenden Zeitfahren gibt es keine signifikanten Unterschiede zwischen den Konzentrationen.Background: The influence of carbohydrates on performance in endurance sports has already been studied in great detail. Isomaltulose is a naturally occurring disaccharide consisting of a glucose and a fructose molecule. In contrast to sucrose and maltose, it is hydrolized very slowly in the small intestine. The increase in blood glucose and insulin is therefore flatter compared to other saccharides. For glucose there is already a dose-response relationship with a maximum recommended amount of 90 g/h. However, such data are still pending for isomaltulose.
Objective: The aim of this study was to investigate the dose-response relationship of isomaltulose. The investigation was to be carried out by measuring various power factors during a two-hour continuous cycling test and a final time trial. Based on the results, training recommendations for the dosage of isomaltulose should be given.
Methods: For the empirical work a double-blind, randomized cross-over study with twelve endurance athletes was conducted.
Results and conclusion: For isomaltulose concentrations between 20 and 60 g/h no dose- response relationship could be demonstrated. There is no difference between the concentrations in terms of efficiency, physiological parameters or substrate use. There are also no significant differences between the concentrations in the performance at the final time trial
Impact of collagen peptide supplementation together with long-term resistance training on maximal strength and muscle size in healthy adults – A systematic review and meta-analysis
No full textIntroduction & Purpose
Of late, numerous studies have investigated the use of collagen peptides (CP) as an ergogenic aid to boost sports performance, although CP is frequently referred to as low-quality protein. Given the high content of glycine, proline, and hydroxyproline in collagen proteins, the current rationale behind the potential impact of CP supplementation may revolve around the incorporation of these amino acids into muscle and tendon tissues (Holwerda & van Loon, 2022). There have been reports of a notable increase in the uptake of these specific amino acids within two hours after the ingestion of 15 g gelatine, coupled with six minutes of rope skipping, as observed in human serum (Shaw et al., 2017). The combination of resistance training (RT) with immediate CP administration seems to serve as a potent stimulus for enhancing anabolic pathways such as phosphatidylinositol 3 - kinase - protein kinase B (PI3k - Akt), mitogen-activated protein kinase (MAPK) and the mechanistic target of rapamycin (mTOR) to induce myofibrillar hypertrophy and collagen synthesis (Centner et al. 2022). Some studies have already demonstrated increased muscle mass gains following CP intake together with exercise interventions (Balshaw et al., 2023), but not all (Centner et al., 2019). Since maximal strength is highly associated with muscular size (Balshaw et al., 2021) several trials have also investigated strength outcomes in various exercises accompanied with CP administration with equivocal results (Jendricke et al., 2019; Zdzieblik et al., 2021). Based on aforementioned findings and the fact that no systematic review and/or meta-analysis has examined the impact of long-term CP supplementation linked with RT on muscular adaptation and strength yet, a meta-analysis is conducted to figure out whether regular CP intake with RT is associated with improvements in maximal strength and increased muscle size.
Methods
The systematic review and meta-analysis was conducted based on PERSiST (implementing Prisma in Exercise, Rehabilitation, Sport medicine and SporTs science) guidelines. Studies investigating healthy adults (≥ 18 years of age, male & female) with a body mass index of 18.5 to 31 kg/m² were included. Both low and professional training status of subjects were suitable for inclusion. Participants had to ingest CP (as treatment group) daily at least for eight weeks, the control group a calorie or non-calorie matched placebo (PLA). Only studies with an accompanying RT of at least two times a week were included. Manuscripts had to be human randomized controlled trials (RCT). Studies adding creatine or caffeine as fortification were excluded. Literature search was carried out in March 2024 in PubMed, Scopus, CINAHL and SPORTDiscus without any restrictions. The following search string was applied in all databases: “collagen AND (peptide OR peptides OR supplement OR supplementation OR hydrolysate) AND (muscle strength OR architecture OR size) [AND (only added in Scopus)] NOT (disease OR skin OR osteoporosis OR osteoarthritis)”. References of included studies and Google Scholar were also screened (forward & backward search) and if eligible, handpicked. The following parameters of studies were chosen for each item: Muscle size: volume (cm³) of quadriceps (and also rectus femoris, vastus intermedius, lateralis and medialis alone), gluteus maximus & hamstrings; CSA (cm²) of the thighs; thickness (cm) of medial gastrocnemius, vastus lateralis, intermedius and rectus femoris. Maximal strength: maximal voluntary contraction and one-repetition maximum of both upper- and lower-body exercises. The Physiotherapy Evidence Database (PEDro) scale was used to assess risk of bias. Meta-analysis was conducted in Jamovi 2.4.11 using the standardized mean difference (SMD) of change scores (post – pre values, resulting in Δ mean and Δ SD) and a random effects model. Certainty of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach.
Results
After duplicate removal, 847 studies were screened. Seventeen seemed to meet eligibility criteria. Due to some limitations such as missing and too short training interventions as well as an insufficient control group design, nine studies, all of them being RCT’s, were included. Six records sourced from website searches and citation investigations ultimately resulted in exclusion due to reasons mentioned earlier. 385 subjects, aged ~18 – 65, participated in the included studies. CP and PLA were administered daily ranging from 5 g (n = 2) to 15 g (n = 7) for at least 8 weeks. Three and six studies supplemented either maltodextrin or a non-caloric PLA, respectively. Dietary protein intake have not changed significantly throughout the trials. Training status of subjects varied, from either untrained to resistance trained (being able to squat 100% of the individual body weight) before study commencements. All nine studies prescribed a RT regimen of three times a week. None of the included studies achieved a total score below “good” (6 - 8), which implicates low risk of bias overall. Muscle size was investigated in 175 subjects in five studies using either MRI or sonography. CP intake led to a statistical significant pooled estimate (ES = 0.35, p = .002, I² = 0%, CI [0.13, 0.57], Figure 1). Nine studies including 385 subjects resulted in a significantly higher maximal strength following CP supplementation (ES = 0.23, p < .01, I² = 0.01%, CI [0.13, 0.57], Figure 1) compared to placebo. Overall, certainty of evidence for both parameters was low due to wide confidence intervals and varying training status of subjects.
Discussion
To the best of our knowledge, this is the first systematic review and meta-analysis examining the effects of long-term CP supplementation alongside regular RT on maximal strength and muscle size in healthy adults. Our findings suggest that prolonged (≥ 2 months) CP intake may significantly improve muscle size accrual and maximal strength, albeit with a low level of evidence. Similar to leucine, a single bolus of CP has been shown to evoke a higher upregulation of key anabolic pathways (PI3K - Akt, MAPK) involved in myofibrillar protein synthesis four hours following RT (Centner et al., 2022). Additionally, an in-vitro experiment treating C2C12 cells with the dipeptide hydroxyprolyl - glycine inducing phosphorylation of p70S6k, mTOR and Akt, suggesting myogenic differentiation (Kitakaze et al., 2016). CP also positively impacted maximal strength concurrently with muscle size. Among other factors, muscle fiber composition, muscle architecture, neural activation and specific tension also contribute to muscle strength. Significantly higher evoked contractile twitch peak torque but no quadriceps tension, muscle architectural differences and lack of muscle fiber type adaptation occurred in long-term trials, thus assuming a probable adaptation of passive tissue components (Balshaw et al., 2023; Kirmse et al., 2019).
Conclusion
A several-week regimen of CP supplementation alongside RT seems to offer advantages to healthy, active adults aiming to enhance both maximal strength and muscle size. A daily intake of 15 g CP seems to induce these adaptations. Future trials are encouraged to identify the optimal CP dosage, composition, absorption and incorporation into collagenous tissues.
References
Balshaw, T. G., Funnell, M. P., McDermott, E., Maden-Wilkinson, T. M., Abela, S., Quteishat, B., Edsey, M., James, L. J., & Folland, J. P. (2023). The effect of specific bioactive collagen peptides on function and muscle remodeling during human resistance training. Acta Physiologica, 237(2), Article e13903. https://doi.org/10.1111/apha.13903
Balshaw, T. G., Maden-Wilkinson, T. M., Massey, G. J., & Folland, J. P. (2021). The human muscle size and strength relationship: Effects of architecture, muscle force, and measurement location. Medicine & Science in Sports & Exercise, 53(10), 2140–2151. https://doi.org/10.1249/MSS.0000000000002691
Centner, C., Jerger, S., Mallard, A., Herrmann, A., Varfolomeeva, E., Gollhofer, S., Oesser, S., Sticht, C., Gretz, N., Aagaard, P., Nielsen, J. L., Frandsen, U., Suetta, C., Gollhofer, A., & König, D. (2022). Supplementation of specific collagen peptides following high-load resistance exercise upregulates gene expression in pathways involved in skeletal muscle signal transduction. Frontiers in Physiology, 13, Article 838004. https://doi.org/10.3389/fphys.2022.838004
Centner, C., Zdzieblik, D., Roberts, L., Gollhofer, A., & König, D. (2019). Effects of blood flow restriction training with protein supplementation on muscle mass and strength in older men. Journal of Sports Science & Medicine, 18(3), 471–478.
Holwerda, A. M., & van Loon, L. J. C. (2022). The impact of collagen protein ingestion on musculoskeletal connective tissue remodeling: A narrative review. Nutrition Reviews, 80(6), 1497–1514. https://doi.org/10.1093/nutrit/nuab083
Jendricke, P., Centner, C., Zdzieblik, D., Gollhofer, A., & König, D. (2019). Specific collagen peptides in combination with resistance training improve body composition and regional muscle strength in premenopausal women: A randomized controlled trial. Nutrients, 11(4), Article 892. https://doi.org/10.3390/nu11040892
Kirmse, M., Oertzen-Hagemann, V., de Marées, M., Bloch, W., & Platen, P. (2019). Prolonged collagen peptide supplementation and resistance exercise training affects body composition in recreationally active men. Nutrients, 11(5), Article 1154. https://doi.org/10.3390/nu11051154
Kitakaze, T., Sakamoto, T., Kitano, T., Inoue, N., Sugihara, F., Harada, N., & Yamaji, R. (2016). The collagen derived dipeptide hydroxyprolyl-glycine promotes C2C12 myoblast differentiation and myotube hypertrophy. Biochemical and Biophysical Research Communications, 478(3), 1292–1297. https://doi.org/10.1016/j.bbrc.2016.08.114
Shaw, G., Lee-Barthel, A., Ross, M. L., Wang, B., & Baar, K. (2017). Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. The American Journal of Clinical Nutrition, 105(1), 136–143. https://doi.org/10.3945/ajcn.116.138594
Zdzieblik, D., Jendricke, P., Oesser, S., Gollhofer, A., & König, D. (2021). The influence of specific bioactive collagen peptides on body composition and muscle strength in middle-aged, untrained men: A randomized controlled trial. International Journal of Environmental Research and Public Health, 18(9), Article 4837. https://doi.org/10.3390/ijerph1809483
Effects of long-term periodized carbohydrate intake on body composition, substrate metabolism and running performance in recreational active men: A pilot trial
No full textIntroduction & Purpose
It is important to consider the impact of nutrition on training adaptations and performance outcomes (Jeukendrup, 2017). The present study was therefore conducted with the objective of determining whether long-term periodizing carbohydrate (CHO) intake during an eight-week endurance training plan has any benefit in comparison to a traditional high-CHO or low-CHO diet in terms of running performance, substrate metabolism and body composition in recreational active males.
Methods
In a controlled, randomised, parallel-group and free-living design, recreationally active runners (n = 24, VO2 peak: 51 ± 8 mL·min-1·kg-1) completed 8 weeks of an ad-libitum dietary intervention (LCHF[low CHO, high fat]/CHO: 4-week regimen with ≤ 50 g CHO per day directly followed by a 4-week regimen comprising 50-60% of daily energy intake from CHO, n = 8; CHO/CHO: 8-week regimen comprising 50-60% of daily energy intake from CHO, n = 9; LCHF/LCHF: 8-week regimen with ≤ 50 g CHO per day, n = 7) together with 5 prescribed sessions of an endurance training program. Dietary recalls were conducted 3 times a week. Body composition, performance and substrate metabolism were assessed 3 times during the study (T -0, T -1 and T -2) using bioelectric impedance and a graded exercise test on a treadmill starting at 6 km·h−1 with increasing speed by 1.5 km·h−1 every 3 minutes until exhaustion. Data were analysed using a 2-way mixed ANOVA and are presented as mean ± STD. Significance was set at p < .05.
Results
Peak running speed (PRS) and time to exhaustion (TTE) demonstrated an increase over time, with no additional benefit observed in relation to any group. Total fat oxidation and maximum fat oxidation (MFO) increased in the first half of the LCHF/CHO diet and decreased during the CHO rich diet (p < .001). In LCHF/LCHF fat oxidation and MFO increased from T -0 to T -1 (p < .001) and remained unchanged at T -2. In CHO/CHO no changes in fat oxidation or MFO were observed (p > .05). Total fat oxidation and MFO were significantly higher at T -1 in LCHF/CHO and LCHF/LCHF compared to CHO/CHO (p < .05). However, at T -2 fat oxidation and MFO were significantly higher in LCHF/LCHF compared to LCHF/CHO and CHO/CHO (p < .05). Significant reductions in weight, BMI, and absolute fat mass were observed in LCHF/CHO from T -0 to T -1 (p < .05) without any further changes until T -2. For LCHF/LCHF weight and BMI were significantly reduced in the first four weeks (p < .001) and even further reduced in the second half (p < .05). For CHO/CHO no significant changes in body composition were observed (p > .05).
Discussion & Conclusion
As previously noted, a high-fat diet resulted in a greater reliance on fat oxidation during exercise (Cao et al., 2021). Here, long-term periodisation of CHO according to the preferred training adaptation leads to changes in substrate metabolism during exercise in terms of improved fat oxidation during a LCHF diet and restoration of CHO oxidation during a CHO-rich diet. Despite the observed improvements in PRS and TTE over the course of the study, no significant advantage was demonstrated by any of the groups in comparison to the other trial groups.
References
Cao, J., Lei, S., Wang, X., & Cheng, S. (2021). The effect of a ketogenic low-carbohydrate, high-fat diet on aerobic capacity and exercise performance in endurance athletes: A systematic review and meta-analysis. Nutrients, 13(8), Article 2896. https://doi.org/10.3390/nu13082896
Jeukendrup, A. E. (2017). Periodized nutrition for athletes. Sports Medicine, 47(S1), 51-63. https://doi.org/10.1007/s40279-017-0694-
Kinect-based detection of self-paced hand movements: Enhancing functional brain mapping paradigms
No full textImprovement of the digestion of cattle slurry via the process of co-digestion
No full textThe use of maize (Zea mays) as a co-substrate with cattle slurry for the production of biogas was investigated in detail by running several long term digestion trials under different operational conditions in laboratory scale semi-continuous digesters. These conditions included varying the organic loading rate (OLR) from 2 to 6 g VS l-1 d-1, the proportion of cattle slurry from 25 to 100%, and the recirculating regime.Results indicated that the co-digestion of cattle slurry and maize was viable at all loading rates tested with the greatest volumetric methane yield, 1.46 l l-1 d-1, produced at a 5 g VS l-1 d-1 OLR consisting of 40% cattle slurry; this corresponded to a specific methane yield of 0.26 l g-1 VS added. Successful digestion was shown at retention times as low as 15 days where a volumetric methane yield of 1.26 l l-1 was produced. Co-digestion had a pronounced effect on the volumetric methane yield with improvements of up to 355% when compared to the digestion of cattle slurry alone. Additionally, the OLR could be doubled by the addition of an equal quantity of maize, on a VS basis, with the volumetric methane yield increasing by over 200% without a great loss of the methane potential of the maize.For each trial undertaken in this research the actual methane yield produced from co-digestion was compared to that calculated to be produced. Support for synergy was shown in the first two trials where the actual methane yield exceeded that predicted however, the method used to calculate the predicted yield was suggested to be an inaccurate determination. To address this inaccuracy a trial was designed testing the digestion of the two substrates alone and together under the same operational conditions and methodology. A comparison between the mono and co-digestion trials indicated that the addition of maize to cattle slurry produced a methane yield that more or less equalled that calculated from the sum of the cattle slurry and maize alone. This brought the early indications of synergy into doubt with suggestions that they were the result of an inaccurate determination of the predicted yield and of inhibition washout.In the final part of the research an attempt was made to improve the volumetric methane yield by introducing solids recirculation to the co-digestion process with the objective of maintaining the slowly degradable fraction of the maize and cattle slurry in the digester for longer periods. This proved not to be a viable option with the methane production showing a decline; at an OLR of 5 g VS l-1 d-1, consisting of 50% cattle slurry, a decline of 0.31 l l-1 d-1 occurred. Solids recirculation was also introduced to the mono-digestion process to determine whether the differences shown in the co-digestion trial were a result of recirculating the solids of the cattle slurry, the maize or a combination of the two. Results showed that both substrates produced unstable conditions indicating that the co-digestion trial was not the result of just one substrate failing. Liquid recirculation was also tested on the co-digestion of the substrates and while no decline was observed no improvement was produced.KEYWORDS: Anaerobic digestion, co-digestion, cattle slurry, maize, solids recirculatio
Coupled oxidation–reduction of butanol–hexanal by resting Rhodococcus erythropolis NCIMB 13064 cells in liquid and gas phases
No full textRhodococcus erythropolis is a promising Gram-positive bacterium capable of numerous bioconversions including those involving alcohol dehydrogenases (ADHs). In this work, we compared and optimized the redox biocatalytic performances of 1-butanol-grown R. erythropolis NCIMB 13064 cells in aqueous and in non-conventional gas phase using the 1-butanol–hexanal oxidation–reduction as model reaction. Oxidation of 1-butanol to butanal is tightly coupled to the reduction of hexanal to 1-hexanol at the level of a nicotinoprotein–ADH-like enzyme. Cell viability is dispensable for reaction. In aqueous batch conditions, fresh and lyophilized cells are efficient redox catalysts (oxidation–reduction rate = 76 micromol min−1 g cell dry mass−1) being also reactive towards benzyl alcohol, (S)-2-pentanol, and geraniol as reductants. However, butanol hexanal oxidation–reduction is strongly limited by product accumulation and by hexanal toxicity that is amajor factor influencing cell behavior and performance. Reaction rate is maximal at 40 ◦C pH 7.0 in aqueous phase and at 60 ◦C- pH 7.0–9.0 in gas phase. Importantly, lyophilized cells also showed to be promising redox catalysts in the gas phase (at least 65 micromol min−1 g cell dry mass−1). The system is notably stable for several days at moderate thermodynamic activities of hexanal (0.06–0.12), 1-butanol (0.12) and water (0.7)
Structure of β-lactoglobulin microgels formed during heating as revealed by small-angle X-ray scattering and light scattering
No full textWe have investigated the structure of microgels formed during heating of demineralized β-lactoglobulin (βlg) solutions at pH 5.9 by small-angle X-ray scattering (SAXS) and light scattering. First, unheated βlg solutions were characterized at different pH values between 2.0 and 7.0. At pH 5.9, βlg solutions contain mainly dimers (with a radius of approx. 2 nm), which coexist with a small number of larger oligomers (approx. 4 nm). Afterwards, βlg microgels, which form upon heating, were studied. They exhibit an average hydrodynamic radius around 130 ± 20 nm and an average molar mass around 7 × 10⁸ g mol⁻¹. We followed the temporal evolution of the various structures that form after different heating times using subsequent SAXS measurements of the entire sample, the soluble fraction where the βlg microgels were removed, and the solvent. After an hour of heating at 85 °C the maximum yield of the βlg microgels (ca. 70%) is almost reached. Interestingly, the SAXS data show a correlation peak corresponding to a characteristic distance of about 9 nm, indicating an internal organization of the microgels. During the heating procedure the pH increases from pH 5.9 to approximately 6.6, which is induced by the partial conversion of βlg into βlg microgels that exhibit less buffering capacity than native protein. The remaining soluble fraction consists of native βlg and some small aggregates, whose number increases on the cost of native βlg as heating time proceeds. We propose that the formation of these lower molecular mass aggregates is triggered by the increased pH
A low nitrogen fertiliser rate in oat–pea intercrops does not impair N2 fixation
No full textIntercropping is commonly used in low-input systems but could also be a strategy for higher input systems. Three ratios of substitutive oat–pea intercrops were tested on a fertile soil in eastern Austria with application of a low nitrogen (N) fertiliser rate (6 g N m−2) versus an unfertilised control to assess the effect of intercropping and low N fertilisation on dinitrogen fixation (NFIX). The above-ground dry matter (AGDM) and N yield of intercrops increased with N fertilisation, but the increase occurred only in oat, while pea was not affected by N fertilisation. Pure pea stands and intercrops with high pea share resulted in N sparing in the soil at harvest, as the soil mineral N was higher than in pure oat. Half of the applied amount of N was recovered by the AGDM of crops and half remained in the soil at harvest. The NFIX per unit area was highest in pure pea. Intercropping considerably reduced NFIX, especially in intercrops with low pea share. NFIX per unit of AGDM of pea, however, was neither affected by intercropping nor by N fertilisation. Consequently, a low amount of N fertilisation of oat–pea intercrops on a fertile soil can increase overall performance of the system through increasing the performance of oat without impairing that of pea
Improved cooperativity of spin-Labile iron(III) centers by self-assembly in solution
No full textSupramolecular principles have been applied for improving the spin crossover activity of metal centers due to cooperative effects in solution. Thus, incorporation of alkyloxy tails at the phenyl group of Fe(sal₂trien) 2a provides amphiphilic complexes Fe(sal-OR₂trien) 2b−d (b, R = C₆H₁₃; c, R = C₈H₁₇; d, R = C₁₈H₃₇) comprising an apolar group for supramolecular organization and a polar headgroup with potential spin crossover activity due to the presence of a spin-labile iron(III) center. Self-assembly of these complexes in solution resulted in the formation of microsize and submicrosize particles when the alkyl chain was long enough (2d) but not with shorter chains (2a−c). Solutions of 2d showed enhanced spin crossover activity as compared to complexes 2a−c, both in terms of transition temperature and steepness of the transition. This observation has been correlated to an improved cooperativity of the metal centers in 2d due to self-assembly, thus facilitating a tandem spin transition
Improved Cooperativity of Spin-Labile Iron(III) Centers by Self-Assembly in Solution
No full textImproved Cooperativity of Spin-Labile Iron(III) Centers by Self-Assembly in Solutio
