Article
Veterinary Sciences
Constance de Meeus D'Argenteuil, Berit Boshuizen, Carmen Vidal Moreno de Vega, Luc Leybaert, Lorie de Mare, Klara Goethals, Ward De Spiegelaere, Maarten Oosterlinck, Catherine Delesalle
Summary: The study reveals that after training, muscle fiber structures tend to become smaller and more capable of receiving and processing fuel delivery rapidly, with the vastus lateralis showing the most significant plasticity. Additionally, there are important differences in baseline and training-specific modulation between different muscle groups.
FRONTIERS IN VETERINARY SCIENCE
(2021)
Article
Sport Sciences
Yujia Liu, Peter M. Christensen, Ylva Hellsten, Lasse Gliemann
Summary: Continuous moderate-intensity training and interval training with high intensity lead to increases in capillarization in sedentary individuals, while low-intensity training has less effect. The duration of training intervention does not affect the magnitude of capillary growth in sedentary individuals. Already trained subjects do not show additional increase in capillarization with various types of training.
MEDICINE & SCIENCE IN SPORTS & EXERCISE
(2022)
Article
Physiology
Kasper Degn Gejl, Lars G. Hvid, Erik P. Andersson, Rasmus Jensen, Hans-Christer Holmberg, Niels Ortenblad
Summary: The study compared force-generating capacity and Ca2+ sensitivity of muscle fibers from arms and legs of highly trained cross-country skiers. It found that MHC II fibers had greater Ca2+-activated force and specific force in both arms and legs, while MHC I fibers exhibited higher specific force in the arms compared to the legs.
FRONTIERS IN PHYSIOLOGY
(2021)
Article
Physiology
Jan-Michael Johansen, Arnstein Sunde, Jan Helgerud, Lars Erik Gjerlow, Oyvind Storen
Summary: This study found that individual changes in training distribution led to increased VO2max in four out of six well-trained cross-country skiers. Three out of six athletes reduced total training volume while four out of six increased HIT volume.
FRONTIERS IN PHYSIOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Zhihong Sun, Yan Zhang, Datao Xu, Yaqi Fei, Qiner Qiu, Yaodong Gu
Summary: This study investigated the changes in blood indices, specific athletic abilities, and physical fitness of outstanding cross-country skiers trained in the subalpine. The results showed that after 6 months of subalpine training, the skiers improved their oxygen-carrying capacity, anabolism, and specific athletic abilities. Both male and female athletes showed significant improvements in physical endurance, acid tolerance, and absolute strength.
APPLIED SCIENCES-BASEL
(2022)
Review
Environmental Sciences
Arkaitz Castaneda-Babarro, Paula Etayo-Urtasun, Patxi Leon-Guereno
Summary: Some studies suggest that strength training is effective for improving performance, double-poling economy, and maximal strength in cross-country skiers. Concurrent training, combining endurance and maximal strength training, appears to be beneficial for performance enhancement.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2022)
Article
Physiology
Rune Kjosen Talsnes, Sigrid Nordgarden, Jan Kocbach, Guro Strom Solli
Summary: This study compared the effects of one long session versus two shorter sessions of low-intensity training on cross-country skiers. The results showed that skiers performed at slightly higher speeds during the two shorter sessions, but there were no significant differences in physiological responses and perceived training stress.
INTERNATIONAL JOURNAL OF SPORTS PHYSIOLOGY AND PERFORMANCE
(2022)
Article
Environmental Sciences
Yichao Yu, Ruolin Wang, Dongye Li, Yifan Lu
Summary: The current observational study monitored the physiological performance of elite Chinese cross-country skiers living and training at a moderate altitude for 4 weeks. Tests were conducted to investigate changes in lactate threshold, maximal oxygen uptake, blood, and body composition. The results showed significant increases in lactate threshold velocity, lactate threshold heart rate, and upper body muscle mass after moderate altitude training, while maximum oxygen uptake decreased. Other aerobic capacity parameters did not significantly improve after returning to sea level. The findings highlight the importance of carefully planning exposure time, training load, and nutritional strategies for optimal training at moderate altitudes for skiers.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2023)
Article
Engineering, Biomedical
Camilla Pierella, Chiara D'Antuono, Giorgia Marchesi, Clizia E. Menotti, Maura Casadio
Summary: As the global population ages, there is an increasing demand for assistive technology and effective human-machine interfaces to address motor disabilities in older adults. This study investigated the impact of two weeks of training with a myoelectric computer interface (MCI) on motor functions in young and old adults. The results showed significant improvements in cursor control and muscle coordination in both groups. The participants became faster and more accurate with the training, and the system usability and quality were highly rated. The findings suggest that MCI training can be a powerful tool in assistive technologies for both young and old adults.
IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING
(2023)
Article
Medicine, General & Internal
Anna Mika, Piotr Mika, Lukasz Oleksy, Anita Kulik
Summary: This study evaluated the changes in bioelectrical activity of lower limb muscles in claudicating patients during a 12-week supervised treadmill training program. The results indicated that both proximal and distal muscles showed beneficial changes after the training period, suggesting that increased foot plantar flexion and stronger push-off as well as greater hip extension were the main mechanisms contributing to the observed improvement in gait pattern.
JOURNAL OF CLINICAL MEDICINE
(2022)
Article
Physiology
John O. Osborne, Guro S. Solli, Tina P. Engseth, Boye Welde, Bente Morseth, Dionne A. Noordhof, Oyvind Sandbakk, Erik P. Andersson
Summary: This study describes and compares the annual physical training characteristics between Norwegian female cross-country skiers and biathletes across competition levels and age categories. The results show that XC skiers have a higher total training volume compared to biathletes, likely due to the different demands of the two sports. Biathletes compensate with a higher proportion of ski training, particularly in the skating technique.
INTERNATIONAL JOURNAL OF SPORTS PHYSIOLOGY AND PERFORMANCE
(2023)
Article
Developmental Biology
Hasan Asfour, Estelle Hirsinger, Raquel Rouco, Faouzi Zarrouki, Shinichiro Hayashi, Sandra Swist, Thomas Braun, Ketan Patel, Frederic Relaix, Guillaume Andrey, Sigmar Stricker, Delphine Duprez, Amalia Stantzou, Helge Amthor
Summary: The mechanism of pattern formation during limb muscle development is not well understood. This study showed that bone morphogenetic proteins (BMP) signaling plays a crucial role in the expansion of embryonic limb muscle progenitor cells (MPCs) and the establishment of the proximodistal muscle pattern. Overexpression of inhibitory human SMAD6 (huSMAD6) disrupted BMP signaling in limb MPCs, resulting in impaired migration, proliferation, and myogenic lineage progression. Loss of HOXA11 expression in early limb MPCs was observed when huSMAD6 was overexpressed. These findings highlight the importance of BMP signaling and Hox gene expression in limb muscle development.
Article
Public, Environmental & Occupational Health
Yin Qin, Hui Chen, Xiaoying Liu, Jiwei Wu, Yinxin Zhang
Summary: This study compared the effects of whole-body electromyostimulation (WB-EMS) training and traditional resistance training on muscle strength and body composition in moderately trained males. The results showed that WB-EMS had similar effects to traditional training in moderately trained males, with the exception of a significantly greater increase in elbow flexor strength.
FRONTIERS IN PUBLIC HEALTH
(2022)
Article
Anatomy & Morphology
Anton Ronnblom, Lars-Eric Thornell, Farhan Shah, Krister Tano, Per Stal
Summary: The function of the middle ear muscles in hearing and protection is still unclear. This study analyzed the morphology, fiber composition, and metabolic properties of these muscles, and found that they have a high proportion of fast contracting myosin fibers and unique muscle characteristics. The middle ear muscles differ from other muscles in terms of fiber size, capillarization, oxidative activity, and nerve density.
JOURNAL OF ANATOMY
(2023)
Article
Multidisciplinary Sciences
Morgane Pengam, Christelle Goanvec, Christine Moisan, Bernard Simon, Gaelle Albacete, Annie Feray, Anthony Guernec, Aline Amerand
Summary: This study aimed to compare the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on metabolic processes in two different muscle types. The results showed that both training protocols led to specific muscular responses, with the genes involved being more significantly upregulated in the slow-twitch (soleus) muscle compared to the fast-twitch (extensor digitorum longus) muscle. HIIT showed better endurance performance and oxidative capacities in both muscles.
Article
Cell Biology
Martin Eisemann de Almeida, Joachim Nielsen, Maria Houborg Petersen, Emil Kleis Wentorf, Niklas Bigum Pedersen, Kurt Jensen, Kurt Hojlund, Niels ortenblad
Summary: This study used quantitative transmission electron microscopy to analyze the morphology of lipid droplets and mitochondria in skeletal muscle cells. It found that excessive storage of large lipid droplets in patients with type 2 diabetes was improved after high-intensity interval training, making it more similar to the characteristics of non-diabetic individuals.
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY
(2023)
Editorial Material
Neurosciences
Joachim Nielsen
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Sport Sciences
Anna Katharina Dunst, Clemens Hesse, Olaf Ueberschaer, Hans-Christer Holmberg
Summary: During maximal cycling sprints, efficiency is determined by muscle fiber composition and cadence-dependent power output. This study introduces the concept of optimal efficiency, which eliminates the impact of cadence, and compares it to actual data. The time course of maximal power output is proposed as an indicator of changes in optimal efficiency.
Article
Physiology
Christopher T. A. Lewis, Lee Tabrizian, Joachim Nielsen, Jenni Laitila, Thomas N. Beck, Mathilde S. Olsen, Marija M. Ognjanovic, Per Aagaard, Rune Hokken, Simon Laugesen, Arthur Ingersen, Jesper L. Andersen, Casper Soendenbroe, Jorn W. Helge, Flemming Dela, Steen Larsen, Ronni E. Sahl, Tue Romer, Mikkel T. Hansen, Jacob Frandsen, Charlotte Suetta, Julien Ochala
Summary: Lewis et al. investigated the influence of training status on relaxed myosin conformations and found that moderate physical activity leads to a shift in relaxed myosin conformation, resulting in reduced ATP consumption. Their study revealed that physical activity level and training type can influence resting skeletal muscle myosin dynamics, suggesting that environmental stimuli such as exercise can rewire the molecular metabolism of human skeletal muscle through myosin.
JOURNAL OF GENERAL PHYSIOLOGY
(2023)
Article
Neurosciences
Javier Botella, Camilla T. Schytz, Thomas F. Pehrson, Rune Hokken, Simon Laugesen, Per Aagaard, Charlotte Suetta, Britt Christensen, Niels Ortenblad, Joachim Nielsen
Summary: This study investigated the mitochondrial structural characteristics in skeletal muscle of strength athletes compared to untrained controls. The results showed that strength athletes had increased mitochondrial cristae density, decreased mitochondrial size, and increased surface-to-volume ratio in their mitochondrial pool, despite similar mitochondrial volume density. In addition, resistance exercise led to mild mitochondrial stress but did not increase the number of damaged mitochondria. Moreover, the study found that acute resistance exercise increased the expression of markers of mitochondrial biogenesis, fission, and mitochondrial unfolded protein responses (UPRmt), and strength-trained individuals showed an enrichment of the UPRmt in their basal transcriptome. These findings suggest that strength athletes have a unique mitochondrial remodeling that minimizes the space required for mitochondria.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Neurosciences
Martin Eisemann de Almeida, Niels Ortenblad, Maria Houborg Petersen, Ann-Sofie Nybole Schjerning, Emil Kleis Wentorf, Kurt Jensen, Kurt Hojlund, Joachim Nielsen
Summary: Using transmission electron microscopy, we found that short-term exercise does not change the morphology, distribution, and contact between lipid droplets and mitochondria in skeletal muscle cells, but it does increase the contact between them. This effect is not affected by obesity or type 2 diabetes.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Sport Sciences
Camilla Tvede Schytz, Niels Ortenblad, Thor Andersen Birkholm, Peter Plomgaard, Lars Nybo, Kristoffer Jensen Kolnes, Ole Emil Andersen, Carsten Lundby, Joachim Nielsen, Kasper Degn Gejl
Summary: Manipulating dietary carbohydrates has an impact on muscle glycogen content and body mass, but does not affect short-term exercise performance. Adjusting pre-exercise glycogen levels can be an effective weight management strategy, especially for athletes involved in short-duration sports.
SCANDINAVIAN JOURNAL OF MEDICINE & SCIENCE IN SPORTS
(2023)
Review
Physiology
Jean-Marc Renaud, Niels ortenblad, Michael J. McKenna, Kristian Overgaard
Summary: Potassium ions play a crucial role in skeletal muscle fatigue, but the changes in K+ intra-to-extracellular gradient alone are not enough to cause significant force decrease unless combined with changes in other ion gradients, such as Na+. Studies have shown that K+-induced force depression can be prevented by decreased ClC-1 channel activity, allowing K+-induced potentiation to dominate during low-moderate intensity muscle contractions. However, during metabolic stress, both K-ATP and ClC-1 channels are activated, leading to force reductions and fatigue.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY
(2023)
Article
Multidisciplinary Sciences
Lisbeth L. V. Moller, Mona S. Ali, Jonathan Davey, Steffen H. Raun, Nicoline R. Andersen, Jonathan Z. Long, Hongwei Qian, Jacob F. Jeppesen, Carlos Henriquez- Olguin, Emma Frank, Thomas E. Jensen, Kurt Hojlund, Jorgen F. P. Wojtaszewski, Joachim Nielsen, Tim T. Chiu, Mark P. Jedrychowski, Paul Gregorevic, Amira Klip, Erik A. Richter, Lykke Sylow
Summary: RhoGDIα is identified as a key regulator in controlling skeletal muscle insulin sensitivity by interacting with Rac1 and modulating GLUT4 translocation. Overexpression of RhoGDIα impairs insulin action and glucose tolerance, and elevated RhoGDIα protein content is observed in skeletal muscles of insulin-resistant patients with type 2 diabetes. This study highlights the clinical relevance of RhoGDIα as a controller of skeletal muscle insulin sensitivity and whole-body glucose homeostasis.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Neurosciences
Camilla Tvede Schytz, Niels Ortenblad, Anne-Kristine Meinild Lundby, Robert Acton Jacobs, Joachim Nielsen, Carsten Lundby
Summary: Differences in oxidative phosphorylation between active and untrained individuals may be explained by higher mitochondrial volume and cristae density in active individuals, with no intrinsic mitochondrial respiratory capacity difference. There are no sex differences in mitochondrial volume and cristae density, oxidative phosphorylation, or normalized oxidative phosphorylation per muscle cristae surface area density.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)