Muscle and Exercise Physiology

A special issue of Medicina (ISSN 1648-9144).

Deadline for manuscript submissions: closed (31 October 2021) | Viewed by 10069

Special Issue Editor

Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium
Interests: muscle physiology; exercise physiology; mechanosensing; metabolism; athletes; patients
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The research field of exercise and muscle physiology covers a wide spectrum. Importantly, this field includes the investigation of athletes’ performance capacities as well as the examination of patient cohorts from the performance level perspective. Hence, our field of exercise and muscle physiology contributes a myriad of research lines, and is gaining in importance. However, the understanding of the effects of, for example, exercise on the performance capacities of patients is still largely limited. On the other hand, basic and applied researchers constantly develop new training programs to improve the exercise capacities of athlete cohorts. These two examples demonstrate that our field is in need of a Special Issue that covers this wide spectrum.

To further develop this positive trend and to enhance the visibility of the important research performed in our research field, I cordially invite you and your co-workers to contribute to the Special Issue “Exercise and Muscle Physiology” set up by Medicina. Both original research and review papers that cover the fascinating range of our domain will be welcome.

Prof. Dr. Frank Suhr
Guest Editor

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Keywords

  • Exercise
  • Muscle
  • Athletes
  • Patients
  • Biomarkers
  • Performance enhancement
  • Metabolism
  • Investigation

Published Papers (4 papers)

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Research

12 pages, 1124 KiB  
Article
Comparison and Performance Validation of Calculated and Established Anaerobic Lactate Thresholds in Running
by Sanghyeon Ji, Aldo Sommer, Wilhelm Bloch and Patrick Wahl
Medicina 2021, 57(10), 1117; https://0-doi-org.brum.beds.ac.uk/10.3390/medicina57101117 - 16 Oct 2021
Cited by 1 | Viewed by 3179
Abstract
Background and Objectives: This study aimed to compare the calculated running velocity at the anaerobic lactate threshold (cLTAn), determined by a mathematical model for metabolic simulation, with two established threshold concepts (onset of blood lactate accumulation (OBLA; 4 mmol∙L−1 [...] Read more.
Background and Objectives: This study aimed to compare the calculated running velocity at the anaerobic lactate threshold (cLTAn), determined by a mathematical model for metabolic simulation, with two established threshold concepts (onset of blood lactate accumulation (OBLA; 4 mmol∙L−1) and modified maximal deviation method (mDmax)). Additionally, all threshold concepts were correlated with performance in different endurance running events. Materials and Methods: Ten sub-elite runners performed a 30 s sprint test on a cycle ergometer adjusted to an isokinetic mode set to a cadence of 120 rpm to determine maximal lactate production rate (VLamax), and a graded exercise test on a treadmill to determine maximal oxygen uptake (VO2max). Running velocities at OBLA, mDmax, and cLTAn were then compared with each other, and further correlated with running performance over various distances (3000 m, 5000 m, and 10,000 m). Results: The mean difference in cLTAn was −0.13 ± 0.43 m∙s−1 and −0.32 ± 0.39 m∙s−1 compared to mDmax (p = 0.49) and OBLA (p < 0.01), respectively. cLTAn indicated moderate to good concordance with the established threshold concepts (mDmax: ICC = 0.87, OBLA: ICC = 0.74). In comparison with other threshold concepts, cLTAn exhibited comparable correlations with the assessed running performances (cLTAn: r = 0.61–0.76, mDmax: r = 0.69–0.79, OBLA: r = 0.56–0.69). Conclusion: Our data show that cLTAn can be applied for determining endurance performance during running. Due to the consideration of individual physiological profiles, cLTAn offers a physiologically justified approach to assess an athlete’s endurance performance. Full article
(This article belongs to the Special Issue Muscle and Exercise Physiology)
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10 pages, 538 KiB  
Article
Using an Electromyography Method While Measuring Oxygen Uptake to Appreciate Physical Exercise Intensity in Adolescent Cyclists: An Analytical Study
by Ștefan Adrian Martin and Roxana Maria Martin-Hadmaș
Medicina 2021, 57(9), 948; https://0-doi-org.brum.beds.ac.uk/10.3390/medicina57090948 - 08 Sep 2021
Viewed by 1470
Abstract
Background and Objectives: During physical exercise, the electrical signal of the muscle fibers decreases due to repeated muscle contractions held at different intensities. The measured signal is strongly related to the motor unit activation rate, which is dependent on the chemical mediators [...] Read more.
Background and Objectives: During physical exercise, the electrical signal of the muscle fibers decreases due to repeated muscle contractions held at different intensities. The measured signal is strongly related to the motor unit activation rate, which is dependent on the chemical mediators and the available energy. By reducing the energy availability, adenosine triphosphate (ATP) production will decrease and therefore the muscle fibers activation rate will be negatively affected. Such aspects become important when taking into account that the training intensity for many young athletes is rather controlled by using the heart rate values. Yet, on many occasions, we have seen differences and lack of relationship between the muscle activation rate, the heart rate values and the lactate accumulation. Materials and Methods: We conducted a prospective analytical study conducted during a 4-month period, on a sample of 30 participants. All study participants underwent an incremental exercise bike test to measure maximum aerobic capacity as well as the muscle activation rate in the vastus lateralis by using an electromyography method (EMG). Results: With age, the EMG signal dropped, as did the electromyography fatigue threshold (EMGFT) point, as seen through p = 0.0057, r = −0.49, CI95% = −0.73 to −0.16, and electromyography maximum reached point (EMGMRP) (p = 0.0001, r = −0.64, CI95% = −0.82 to −0.36), whereas power output increased (p = 0.0186, r = 0.427). The higher the power output, the lower the signal seen by measuring active tissue EMGFT (p = 0.0324, r = −0.39) and EMGMRP (p = 0.0272, r = −0.40). Yet, with changes in median power output, the power developed in aerobic (p = 0.0087, r = 0.47), mixed (p = 0.0288, r = 0.39), anaerobic (p = 0.0052, r = 0.49) and anaerobic power (p = 0.004, r = 0.50) exercise zones increased. Conclusions: There has been reported a relationship between aerobic/anaerobic ventilatory thresholds (VT1 and VT2) and EMGFT, EMGMRP, respectively. Each change in oxygen uptake increased the power output in EMGFT and EMGMRP, improving performances and therefore overlapping with both ventilatory thresholds. Full article
(This article belongs to the Special Issue Muscle and Exercise Physiology)
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10 pages, 1096 KiB  
Article
Acute Exhaustive Exercise under Normoxic and Normobaric Hypoxic Conditions Differentially Regulates Angiogenic Biomarkers in Humans
by Frank Suhr, Sarah Knuth, Silvia Achtzehn, Joachim Mester and Markus de Marees
Medicina 2021, 57(7), 727; https://0-doi-org.brum.beds.ac.uk/10.3390/medicina57070727 - 19 Jul 2021
Cited by 2 | Viewed by 1853
Abstract
Background and Objectives: Angiogenesis describes the outgrowth of new capillaries from already existing ones. Different biomarkers regulate this process. Physical exercise and hypoxia are key stimuli for the activation of different angiogenic molecules, such as the vascular endothelial growth factor (VEGF). matrix metalloproteases [...] Read more.
Background and Objectives: Angiogenesis describes the outgrowth of new capillaries from already existing ones. Different biomarkers regulate this process. Physical exercise and hypoxia are key stimuli for the activation of different angiogenic molecules, such as the vascular endothelial growth factor (VEGF). matrix metalloproteases (MMPs)-2 and -9 or the extracellular matrix cleavage fragment endostatin. The present study aimed to investigate influences of short-term, intensive cycling exercise under both normoxic and normobaric hypoxic conditions on the mentioned parameters. Materials and Methods: Twelve male subjects (age: 23.3 ± 2.0 years) participated in the study. All subjects conducted four intensive cycling tests until individual exhaustion in a randomized order under the following conditions: normoxia, 2000 m, 3000 m and 4000 m above sea level. Blood samples were taken before (pre) and 10 min, 30 min, 60 min and 240 min post exercise and were analyzed by ELISA. Results: VEGF showed a significantly reduced concentration compared to the pre-value solely under 4000 m at 10 min post exercise. MMP-2 showed significantly reduced concentrations at 240 min post exercise under 4000 m. MMP-9 increased at 240 min post exercise under both 2000 m and 4000 m conditions. Endostatin was significantly increased at 10 min post exercise independently of the applied stimulus. Conclusions: The presented data show that intensive short-term exercise bouts facilitate the bioavailability of angiogenic, ECM (extracellular matrix)-related biomarkers. This finding is interesting for both health- and performance-related research as it demonstrates the positive effects of intensive short exercise interventions. Full article
(This article belongs to the Special Issue Muscle and Exercise Physiology)
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12 pages, 878 KiB  
Article
Training Load Measures and Biomarker Responses during a 7-Day Training Camp in Young Cyclists—A Pilot Study
by Yvonne Wahl, Silvia Achtzehn, Daniela Schäfer Olstad, Joachim Mester and Patrick Wahl
Medicina 2021, 57(7), 673; https://0-doi-org.brum.beds.ac.uk/10.3390/medicina57070673 - 29 Jun 2021
Cited by 4 | Viewed by 2528
Abstract
Background and Objectives: During intense training periods, there is a high need to monitor the external and especially the internal training load in order to fine-tune the training process and to avoid overreaching or overtraining. However, data on stress reactions, especially of [...] Read more.
Background and Objectives: During intense training periods, there is a high need to monitor the external and especially the internal training load in order to fine-tune the training process and to avoid overreaching or overtraining. However, data on stress reactions, especially of biomarkers, to high training loads in children and youth are rare. Therefore, in this study, we aimed to investigate the training load of youth athletes during a training camp using a multilevel approach. Materials and Methods: Six trained youth male cyclists performed a 7-day preseason training camp. To investigate the internal training load, every morning, minimally invasive “point-of-care testing” (POCT) devices were used to analyze the following biomarkers: creatine kinase (CK), blood urea nitrogen (BUN), albumin (Alb), bilirubin (Bil), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total protein (TP). Additionally, data of training load measures (HR: heart rate, RPE: rating of perceived exertion, sRPE: session-RPE, TRIMP: training impulse, intensity (RPE:HR), and load (sRPE:TRIMP) ratios), self-perception (person’s perceived physical state, questionnaires on muscle soreness, and sleep quality), and measures of the autonomic nervous system (resting heart rate, heart rate variability) were collected. Two days before and after the training camp, subjects performed performance tests (Graded Exercise Test, Wingate Anaerobic Test, Counter Movement Jump). Results: Primarily, the biomarkers CK, BUN, and Alb, as well as the self-perception showed moderate to large load-dependent reactions during the 7-day training camp. The biomarkers returned to baseline values two days after the last training session. Power output at lactate threshold showed a small increase, and no changes were found for other performance parameters. Conclusions: The study suggests that a multilevel approach is suitable to quantify the internal training load and that different parameters can be used to control the training process. The biomarkers CK, BUN, and Alb are suitable for objectively quantifying the internal training load. The self-perception provides additional subjective information about the internal training load. Full article
(This article belongs to the Special Issue Muscle and Exercise Physiology)
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