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The worsening of heavy traffic necessitates frequent pedal pressing, leading to muscle fatigue. Therefore, understanding muscle activation (MA) during this action enhances driving performance. This study establishes an experimental setup to analyze MA during pedal pressing and its changes on electromyography (EMG) signals of the quadriceps, gastrocnemius and soleus muscles when fatigued. Twenty male participants were requested to repetitively press the brake pedal until fatigue, simulating heavy traffic. Pedal frequencies of 20 and 40 presses per minute were used to replicate traffic variations. EMG signals revealed differential MA based on knee joint position during pedal pressing, with closer proximity to the steering wheel activating lower leg muscles more. Most participants $(N=12)$ maintained an optimal knee angle (100–$110^{\circ }$), experiencing the slowest fatigue. Significant changes in median frequency and MA percentage of EMG signals were observed pre- and post-fatigue, with spectral density shifting to lower frequencies during sustained contraction. Pedal force decreased significantly during fatigue. These findings offer insights into optimizing drivers’ seating positions and understanding the impact of heavy traffic on muscle fatigue.

We investigated the correlation among brain and leg muscle activations by analyzing Electroencephalogram (EEG) and Electromyogram (EMG) signals in different conditions. Twelve subjects performed four tasks, including (1) quarter turns, (2) U-turns, (3) bypass obstacles, and (4) repeating quarter turns and U-turns two times. Then, we quantified the alterations of the complexity of these signals by computing the fractal dimension and sample entropy. The results showed that EEG and EMG signals in the case of the first task are more complex than the second task, in which they are more complex than the third task. Furthermore, the brain and muscle signals show the least complexity in the case of the fourth task. Moreover, we found strong correlations in the variations of fractal dimension ($r=0.9835$) and sample entropy ($r=0.9168$) between EEG and EMG signals in various tasks. Therefore, brain and muscle activations are strongly correlated in different tasks. Similar analyses can be conducted in the case of other organs to decode their correlations.

The study of correlations between different organs under various conditions is a prominent field in biomedical science and engineering. This paper explores the relationship between brain and muscle activities during rest and various limb movements including plantar flexion and knee flexion. We employed complexity measures, calculating the fractal dimension (FD) and sample entropy (SampEn) of electroencephalogram (EEG) and electromyogram (EMG) signals, which serve as indicators of brain and muscle activities, respectively. Our analysis focused on how the complexity variations in these signals correlate across different tasks. The results revealed opposite trends in the complexity of EEG and EMG signals. Specifically, the complexity of EEG signals increased from initial rest to final rest, plantar flexion, and knee flexion, suggesting heightened neural activity likely due to motor planning and execution. Conversely, the complexity of EMG signals decreased, indicating more synchronized and consistent muscle contractions during these movements, reflecting coordinated motor control and reduced variability in muscular activity. This analytical approach can be applied to study the correlations between different organs’ reactions and brain activity across various tasks.

This paper describes four cases of ulnar tunnel compression syndrome caused by the accessory abductor digiti minimi muscle and stresses on the observation that wrist trauma could be an important precipitating factor. Possible pathophysiological explanations of this phenomenon are offered and the anatomy of the accessory abductor digiti minimi muscle is reviewed.

Myxomas of the upper limb are rare and are classified according to their tissue of origin into tumours arising from periosteum, bone or soft tissues such as skin, fascia and muscle. In the literature, one case of intramuscular myxoma of the forearm has been reported. The current report describes the first intramuscular myxoma within the hand muscles.

As age, experience and common sense look at biomechanical, hormonal, genetic and other roles in bone physiology and its disorders, two questions can arise: (a) How did we fail? (b) How could we make it better? The acerbic Sam Johnson said that to teach new things, we should use examples of already known ones. If so, an analogy might help to clarify this article's message for people who work with bones and their disorders.

Assume this: (a) Mythical physiologists were taught that renal physiology depends on "kidney cells" but were taught nothing about nephrons; (b) so they explained renal health and disorders in those terms. (c) For many decades, they "knew" that view was correct (as the ancients "knew" the world was flat). (d) But then others described nephrons and some errors their properties revealed in those views about renal physiology; (e) so controversies began.

Today, an analogous situation confronts real biomechanicians and physiologists. (i) Most of them were taught that osteoblasts and osteoclasts (bone's "effector cells") explain bone physiology without "nephron-equivalent" input, so they explained bone disorders and mechanical effects in those terms. (ii) Yet nephron-equivalent mechanisms and functions, including biomechanical ones, in bones have the same operational relationship to their cells, health and disorders as nephrons and their functions do to renal cells, health and disorders. (iii) Adding that knowledge to former views led to the Utah paradigm of skeletal physiology. It also revealed errors in many former views about bone physiology; (iv) so real controversies have begun.

Biomechanicians, physiologists, clinicians and pharmacologists from whom poor interdisciplinary communication hid that paradigm could think the view in (i) above remains valid, and keep analyzing data and designing studies within its constraints.

Like Wegner's idea of plate tectonics in geology, the Utah paradigm came before its field was ready, so others fought it. But while the plate-tectonics war was won, it has just begun for the Utah paradigm. This article reviews how such things could apply to bone and some of their implications. Its conclusion offers succinct answers to the italicized questions above.

Elite athletics requires maximum effort by the pursuer, exposing the tendons, ligaments and muscles, including the heart muscle, to intense and frequent mechanical and metabolic demands, which may increase the susceptibility to, and severity of, infections in these tissues. Furthermore, intense and frequent exercise with insufficient resting periods can compromise the immune system. Muscles and tendons are more vulnerable to overuse injuries in the recovery period following various infections. Although the etiology and pathogenesis of a substantial proportion of cases of tendinitis and tendinosis are still largely unknown, gram-positive cocci prevail as the most common etiologies in soft tissue infections. The recent identification of binding sites of staphylococci to intercellular tissue matrix components have opened up the possibility of selectively blocking such binding by prior vaccination. New molecular biological methods, enabling the identification of slow-growing bacteria that are difficult to culture, including Bartonella and Rickettsia, have created the possibility of studying the potential role also of such organisms in soft tissue conditions, including myocarditis. Acute myocarditis remains the most frequent form of myocarditis, commonly emerging in the course of an acute respiratory infection. Since myocarditis episodes are frequently subclinical and self-healing, athletes (and others) should generally be recommended rest during infections, especially during the early phase of the infection.

Here, we suggest that new ideas and knowledge about "osteoporosis" reveal necessary new directions for future work. To explain, by 1999, five studies involving a total of 1827 healthy humans from two to over 80 years of age supported this proposal in the Utah paradigm of skeletal physiology: Momentary muscle strength strongly influences and may dominate control of the biologic mechanisms that determine the postnatal strength of load-bearing bones. That italicized proposal differed so much from former views that before 1999, few people thought it deserved testing in humans. The above five studies did finally test it, and they support it.

If true, its implications would affect many things. In part, they include (A), genetic effects on bone strength and "mass", muscle and "osteoporosis"; (B) the pathogenesis, diagnosis, classification, prevention and management of "osteoporosis"; (C) the things osteoporosis-oriented basic, clinical and pharmaceutical research should study; (D) the absorptiometric methods and animal models used to study the disorder; (E) which research projects would receive preferred funding; (F) and the content of future texts, review articles, classroom lectures and many osteoporosis-oriented meetings.

Many might find some of those implications dubious. While we will respect such doubts, this article describes some of those implications so others can exploit them and/or help to resolve any disagreements they may cause. Because they depend on the Utah paradigm of skeletal physiology, some of its pertinent features must be summarized.

Bony tissue induced with recombinant human bone morphogenetic protein-2 (rhBMP-2) in the latissimus dorsi muscle flap (LDMF) of rats was investigated in angiography and histological examination. In five rats, rhBMP-2 with atelopeptide type I collagen (CL) as a carrier was implanted in the muscle pocket of LDMF. In five controls, only CL was implanted in the same manner. Three weeks after the implant, contrast medium was injected into the assending aorta. The LDMF was cut off at the base and exposed in soft X-ray. The implant and the surrounding tissue were then histologically examined.

In the rhBMP-2-implant group, the vascularity was richer, especially around the implant, and radiated to the induced bony tissue. Contrast medium was observed in the vascular cavities of the marrow inside the trabeculae. In the controls, the vascularity was relatively poor and the remnant CL occupied the whole implant space.

This study indicated that rhBMP-2 does not only induce trabeculae in muscle tissue, but also in the marrow, including vessels in the implant and the vascular system around the implant. Then, the induced bony tissue is supported in the circulation by the circulation by the vascular system, as a functional osseous tissue. This phenomenon may be highly beneficial in endogenous tissue engineering and regenerative medicene for skeletal reconstruction using BMP in the future.

Ultrasonography is frequently used to measure the rectus femoris muscle cross-section area, and has been suggested to associate with poor health condition. However, no validation studies have been performed to compare rectus femoris muscle ultrasonography (RFMS) with anatomical planimetry when measuring the muscle cross-sectional area (CSA). This validation study compared the two methods of CSA measurement of unfixed (frozen) and fixed (unfrozen) rectus femoris muscle specimens obtained from elderly human cadavers. Agreement between tests was studied by Bland–Altman analysis. We found a significant difference between planimetry and RFMS of unfixed (frozen) muscle specimens (mean difference, -0.389 cm²; 95% CI, -0.144 to -0.634), p = 0.022. No significant difference was observed between the two methods when measuring fixed (unfrozen) muscle specimens (mean difference, 0.032 cm², 95% CI, -0.007 to -0.070), p = 0.107. In fixed specimens, the 95% limit of agreement between the two methods ranged between 0.12 cm² and -0.06 cm² (<10% deviation); while in unfixed muscle specimens, the range was between 0.28 cm² and -1.06 cm² (~50% deviation). In light of the similar results obtained in fixed specimens, ultrasound is a safe and accurate method of rectus femoris muscle size assessment. In clinical practice, RFMS may be used to detect a decrease in rectus femoris muscle mass, typically associated with malnutrition of the elderly, and may therefore be a simple and practical tool for the screening of malnutrition.

This study aims to develop a viscoelastic database for muscles (VM: vastus medialis and Sr: sartorius) and subcutaneous adipose tissue with multifrequency magnetic resonance elastography (MMRE) coupled with rheological models. MMRE was performed on 13 subjects, at 70-90-110 Hz, to experimentally assess the elastic properties (μ) of passive and active (20% MVC) muscles. Then, numerical shear modulus (μ) and viscosity (η) were calculated using three rheological models (Voigt, Zener, Springpot). The elastic properties, obtained with the Springpot model, were closer to the experimental data for the different physiological tissues (μ_{Springpot_VM_Passive} = 3.67 ± 0.71 kPa, μ_{Springpot_Sr} = 6.89 ± 1.27 kPa, μ_{Springpot_Adipose Tissue} = 1.61 ± 0.37 kPa) and at different muscle states (μ_{Springpot_VM_20%MVC} = 11.29 ± 1.04 kPa). The viscosity parameter increased with the level of contraction (η_{_VM_Passive_Springpot} = 4.5 ± 1.64 Pa.s versus η_{_VM_20%MVC_Springpot} = 12.14 ± 1.47 Pa.s) and varied with the type of muscle. (η_{_VM_Passive_Springpot} = 4.5 ± 1.64 Pa.s versus η_{_Sr_Springpot} = 6.63 ± 1.27 Pa.s). Similar viscosities were calculated for all tissues and rheological models. These first physiologically realistic viscoelastic parameters could be used by the physicians to better identify and monitor the effects of muscle disorder, and as a database for musculoskeletal model.

Context: Shoulder Impingement Syndrome (SIS) is a common clinical condition in general practice and overhead athletes. Alterations in the scapular position can lead to shoulder impingement syndrome. The effect of exercises on shoulder impingement syndrome is studied but the effect of Kinesiotape is not well explored.

Methods: A total of 42 participants were included in the study. The subjects were assessed for SPADI, pain, proprioception, lateral scapula slide test, and pectoral minor length test at the baseline and the subjects were randomly divided into two groups. The intervention group ($n$ = 18) received scapular taping and scapular exercises and the control group ($n$ = 17) received scapular exercises only. Post-outcome measures were taken at 4 weeks and 12 weeks during the intervention. Repeated measures ANOVA was used for the outcome measures and Bonferroni’s test was used to determine the pairwise comparisons at different measurement levels amongst experimental and control groups.

Results: The study consisted of 17 males and 18 females. There was statistical significance in both groups ($p$ < 0.01) over the 4th and 12th weeks. Pain ($p$ < 0.01) and proprioception ($p$ = 0.017) was also statistically significant between both the groups at 4 weeks.

Conclusion: This study concludes that scapular taping can be used as an adjunct with scapular involvement.

The purpose of this short communication is to present an animal model that: (1) allows for controlled, quantifiable loading of muscle and tendon; and (2) can be used to evaluate the response of musculo-skeletal tissues to chronic loading. A loading apparatus was used to move the rabbit foot through any desired angular position and velocity, while continuously measuring moments about the transverse axis of the ankle. A stimulator was triggered at a pre-set location in the range of motion to produce a contraction of the triceps surae and plantaris muscles. Muscle forces measured with an Achilles tendon force transducer were found to correlate well with externally measured ankle extensor moments. The experimental setup was used to provide cyclic loads to the triceps surae and plantaris muscles and Achilles tendon of 16 rabbits for three loading sessions per week over the period of one to eleven weeks. The experimental model described here is appropriate for the systematic study of the adaptation of muscle and tendon to chronic loading because of the repeatability of the setup and the quantification of tissue loads.

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Bench press training seems to be the most common exercise for increasing upper-body strength and control among athletes, fitness enthusiasts, and wellness buffs. Bench presses are usually done by lying down on the bench with the back, shoulders, and buttocks in touch. The bench press training surveillance systems with technical advancements are rarely seen in the research domain. Therefore, this paper presents a novel bench press training monitoring method (BPTMM) by evaluating mechanical joint rotational friction using Internet of Things (IoT) sensors. The bench press is a common upper body strength-building and muscle-building conditioning exercise. The bench press and the squat and deadlift are the three primary lifts performed in powerlifting competitions. Artificial intelligence aids in risk prediction and suggests possible positions. There is a 96.8% accuracy rate in surveillance and categorization, according to the findings of the experiments.

Sore muscles following unaccustomed eccentric exercise is a common experience. One remarkable aspect of this is the rapid training. A single bout of exercise can provide significant protection against muscle damage and soreness from subsequent bouts. Several studies have shown that such training also increases the optimum muscle length and/or the number of sarcomeres. The present study aimed to test whether this accounts for all the protection. Rats were trained for up to 30 minutes per day on a treadmill, either inclined to 16° (concentrically biased exercise) or declined to 16° (eccentrically biased exercise) for one week. The decline rats were found to have smaller optimum knee angles, or longer muscle lengths, for torque generation by vastus intermedius muscles than the incline rats. When test eccentric contractions were given over the same range of knee angles for each training group, the decline rats showed less damage. When the differences in the optimum length were accounted for and the eccentric contractions were given over the same portion of the torque angle curve, there was no difference between the two groups in the amount of damage that they suffered, suggesting that the shift in optimum was responsible for all of the protection.

Magnetic resonance images and ultrasound images were used to examine the architecture of the distal biceps brachii muscle in 12 unimpaired subjects. The distal biceps brachii tendon continued as an internal aponeurosis that spanned 34± 4% of the length of the biceps brachii long head muscle on average. The distal muscle fascicles inserted at angles to this aponeurosis; fascicles anterior to the aponeurosis inserted at a significantly greater (p ≤ 0.05) angle (17°) than the fascicles posterior to the aponeurosis (14°) in the distal 2 cm of muscle when the elbow was extended. Mean fascicle insertion angles were on average 3–4° greater with the elbow flexed 90° against a 5% maximum voluntary contraction load as compared to their values with the elbow extended. These data provide the basis for designing experiments to measure muscle and tendon motion in vivo.

Quick-release experiments often produce noticeable oscillations on the measured force and length data in the first few milliseconds after the force release. We measured oscillations in experiments with several species (Rattus norvegicus, Galea musteloides, Rana pipiens) and different experimental setups. These oscillations are generally ignored as artifacts.

This study investigates the cause of the oscillations. A biomechanical model of the experimental setup was developed consisting of a geometric model describing the setup and a Hill-type muscle-tendon model including the force-length-velocity relation and a linear spring in series. Muscle properties of each muscle were determined by the ISOFIT method. Model calculations and forward simulations of quick-release experiments based on experimentally determined muscle properties reveal that the observed oscillations are not artifacts (instrument and control), but the result of interactions of muscle-tendon properties with the inertia of muscles, bones and lever system.

To investigate the effect of viscoelastic behavior on instantaneous muscle mechanics, the passive mechanical properties for the range of physiologically relevant rates should be clarified. Therefore, a series of uniaxial extension tests were conducted at various stretching rates using the muscle fiber bundles, which contained extracellular matrix (ECM) and interfibrillar microstructural components. We revealed that the tensile strength is strain rate-sensitive over the examined range, i.e., the muscle fiber bundle failed at 109$\pm$34, 122$\pm$44, and 179$\pm$61kPa (mean$\pm$SD) for strain rates of 0.02, 0.1, and 0.5s${}^{-1}$, respectively. Moreover, we found that the applied stretch was not distributed uniformly even in relaxed conditions; the ratio between maximum and minimum local strains within a specimen was 2–3 on average during stretching and increased up to approximately four just before failure, indicating local mechanical heterogeneity along a fiber bundle and its exaggeration by stretching. Macroscopically, however, the tensile strain at failure was almost constant, $\sim$50%. The local heterogeneity of muscle strain distribution can lead to unstable oscillation in a computational model. Thus, in addition to the intrinsic viscous effects of the muscle fiber itself, those of ECM and interfibrillar microstructural components should be considered in mathematical modeling of skeletal muscle.

Automotive shocks involve various tiers’ speed for different human body tissues. Knowing the behavior of these tissues, including muscles, in different vibration frequency is therefore necessary. The muscle has viscoelatic properties. Dynamically, this material has variable mechanical properties depending on the vibration frequency. A novel technique is being employed to examine the variation of the mechanical impedance of pork muscle as a function of frequency. A force is imposed on the lower surface of the sample and acceleration is measured on its upper surface. These two parameters are measured using sensors. The sample is modeled by Kelvin–Voigt model. These measures allow deducing the change in the mechanical impedance modulus (/$Z_{\mathrm{\text{exp}}}$/ $=$ /Force: Acceleration/) of pork muscle as a function of vibration frequency. The measured impedance has a resonance of approximately 60Hz. Best-fit parameters of theoretical impedance can be deduced by superposition with the experiment result. The variation of Young’s modulus and internal damping of pig’s muscle as a function of frequency are determined. The results obtained between 5Hz and 30Hz are the same as determined by Aimedieu and al in 2003, therefore validating our technique. The Young’s modulus of muscle increases with the frequency, on the other hand, we note a rating decrease of internal damping.