leg muscles
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Gait analysis is clinically relevant in persons with multiple sclerosis (PwMS) and consists of several joint angular displace-ment-time relationships and spatiotemporal parameters. However, it lacks representation by means of diagrams in which knee angle-hip angle and knee angle-ankle angle variations are plotted against each other at the same instants of time. Three-dimensional kinematic analysis was performed on 20 subjects (10 PwMS/10 healthy controls, HCs), and the knee-angle/hip-angle and knee-angle/ankle-angle diagrams of both lower limbs were determined in the sagittal plane while walking on a motorized treadmill. The area (a quantifier of conjoint range of motion) and the perimeter (a quantifier of coordina-tion) of angle-angle diagram loops were calculated. PwMS showed reduced knee-angle/ankle-angle loops compared to HCs (P<0.05, ES = 0.80), whereas the hip-angle/ankle-angle loops between the PwMS and HCs was not significant (P> 0.05). Similarly, the activation of leg muscles showed significant differences between PwMS and HCs (p ranged from 0.05-to 0.001; ES ranged from 1.30 to 1.89). The results indicate that the proposed knee-angle/hip-angle diagram is feasible and could be applied as a reliable tool in future studies aimed at assessing the acute and long-term effects of specific exercise programmes and/or pharmacological treatment in PwMS.

Abstract Background Charcot-Marie-Tooth disease (CMT) is a genetically heterogeneous hereditary neuropathy, and CMT1A is the most common form; it is caused by a duplication of the peripheral myelin protein 22 (PMP22) gene. Mutations in the transient sodium channel Nav1.4 alpha subunit (SCN4A) gene underlie a diverse group of dominantly inherited nondystrophic myotonias that run the spectrum from subclinical myopathy to severe muscle stiffness, disabling weakness, or frank episodes of paralysis. Case presentation We describe a Chinese family affected by both CMT1A and myotonia with concomitant alterations in both the PMP22 and SCN4A genes. In this family, the affected proband inherited the disease from his father in an autosomal dominant manner. Genetic analysis confirmed duplication of the PMP22 gene and a missense c.3917G > C (p. Gly1306Ala) mutation in SCN4A in both the proband and his father. The clinical phenotype in the proband showed the combined involvement of skeletal muscle and peripheral nerves. Electromyography showed myopathic changes, including myotonic discharges. MRI revealed the concurrence of neurogenic and myogenic changes in the lower leg muscles. Sural nerve biopsies revealed a chronic demyelinating and remyelinating process with onion bulb formations in the proband. The proband’s father presented with confirmed subclinical myopathy, very mild distal atrophy and proximal hypertrophy of the lower leg muscles, pes cavus, and areflexia. Conclusion This study reports the coexistence of PMP22 duplication and SCN4A mutation. The presenting features in this family suggested that both neuropathy and myopathy were inherited in an autosomal dominant manner. The proband had a typical phenotype of sodium channel myotonia (SCM) and CMT1A. However, his father with the same mutations presented a much milder clinical phenotype. Our study might expand the genetic and phenotypic spectra of neuromuscular disorders with concomitant mutations.

Abstract: Physical condition is an important role in football because with good physical condition, it will be more likely to achieve. This study aims to determine the level of physical condition of Arema players aged 16 years in Malang City in 2021. The method used in this study is descriptive quantitative which aims to provide a real picture in accordance with what is in the field about the physical condition of Arema Football Academy football players aged 16 years old in Malang in 2021. The results on leg muscle strength have an average of 44.24, speed has an average of 7.73, agility has an average of 9.91, flexibility has an average of 16.60, muscle power limbs have an average of 55.88, endurance has an average of 45.98. It can be concluded that strength (leg muscles) is in sufficient category, speed is in good category, agility is in very good category, flexibility is in very good category, leg muscle power is in good category and endurance is in good category. And the overall physical condition is in the sufficient category. Abstrak: Kondisi fisik merupakan peranan yang penting dalam sepak bola karena dengan kondisi fisik yang baik maka akan lebih berpeluang untuk berprestasi. Penelitian ini bertujuan untuk mengetahui tingkat kondisi fisik pemain arema usia 16 tahun di Kota Malang tahun 2021. Metode yang digunakan dalam penelitian ini merupakan kuantitatif deskriptif yang bertujuan untuk memberikan gambaran nyata sesuai dengan yang ada di lapangan tentang kondisi fisik pemain sepak bola Arema Football Academy umur 16 tahun di Kota Malang tahun 2021. Hasil pada kekuatan otot tungkai memiliki rata-rata 44,24, kecepatan memiliki rata-rata 7,73, kelincahan memiliki rata-rata 9,91, kelentukan memiliki rata-rata 16,60, power otot tungkai memiliki rata-rata 55,88, daya tahan memiliki rata-rata 45,98. Dapat disimpulkan bahwa kekuatan (otot tungkai) masuk kategori cukup, kecepatan masuk kategori baik, kelincahan masuk kategori baik sekali, kelentukan masuk kategori baik sekali, power otot tungkai masuk kategori baik dan daya tahan masuk kategori baik. Dan pada kondisi fisik secara keseluruhan masuk dalam kategori cukup.

Abstract The biogenic amine octopamine (OA) orchestrates many behavioural processes in insects. OA mediates its function by binding to OA receptors belonging to the G protein-coupled receptors superfamily. Despite the potential relevance of OA for controlling locomotion, our knowledge about the role of each octopaminergic receptor still limited. In this study, RNA interference (RNAi) was used to knockdown each OA receptor type in almost all Drosophila melanogaster tissues using a tubP-GAL4 driver to investigate the loss of which receptor affects the climbing ability of adult flies. The results demonstrated that oamb-deficient flies had impaired climbing ability more than those deficient in other receptors receptive for OA. Targeted RNAi-mediated kockdown of oamb in the nervous system or muscular system decreased the climbing ability, indicating that within Drosophila legs, OA through oamb orchestrated the nervous system control and muscular tissue responses. Oamb-deficient adult males showed morphometric changes in the length and width of leg parts. Transmission electron microscopy revealed that the leg muscles oamb-deficient flies have severe ultrastructural changes compared to those of control flies. The severe impairment in the climbing performance of oamb-deficient flies correlates well with the completely distorted leg muscle ultrastructure in these flies. Taken together, we could conclude that OA via oamb plays an important role in the locomotor activity of Drosophila.

Background and Study Aim. Muay thai is a combat sport in which the competitors kick, punch, knee, elbow and growl with their opponents. The strength of the leg muscles can increase the intensity of the kick and its flexibility is a well-known issue for this sport. Determining the most appropriate method for these issues provides important gains to the athletes. One of the methods applied to achieve these gains is acute massage applications. The aim of the study is to evaluate the acute effect of different massage times on squat jump, countermovement jump and flexibility performance. Materials and Methods. Twelve healthy male muay thai athletes (age, 19.83± 1.46 years; height, 175.33± 7.91 cm; body mass, 65.16 ±13.36 kg) participated in the study, who exercised three times a week. The study consists of a single group. The study consists of 4 different massage duration protocols. These protocols consist of no massage (NM), five minutes massage (5MMSG), ten minutes massage (10MMSG) and fifteen minutes massage (15MMSG). Counter movement jump, squat jump, sitting and lying flexibility were measured after each massage period, respectively. All protocols were continued on consecutive days. Results. There was a significant main effect for flexibility (F = 10,872 ; p = 0.00), countermovement jump (F = 4.719 p=.008) and squat jump (F = 6.262 p=.002) performance. The best flexibility, countermovement jump and squat jump performance detected immediately after 5MMSG was respectively 35,16 ± 6,33; 37,17 ± 4,18 and next, 36,05 ± 4,68. Conclusion. As a result, it is recommended that different massage durations are effective in improving physical performance, and 5MMSG before competition is recommended for athletes and coaches to get more performance.

The purpose of the study was to disclose topographic anatomical features of the extra- and intramuscular innervation points of the leg. Materials and methods. 15 adult human subjects and one-month old baby legs at three levels were studied using such methods: cross-sections according to N.I. Pirogov technique, histotopographic sections, macro-microscopic method, histological staining with hematoxylin-eosin and Krutsay. Results. In our macro-microscopic study, the main attention was paid to the individual anatomical variability in the innervation of the lower leg muscles. Study of the nerves of the leg muscles allowed to clarify the course of the neurovascular bundle of the leg at its three levels, taking into account individual age characteristics, and also to show the myeloarchitectonics of both the main nerve trunks and their intramuscular branches. Such differences in the location of the leg muscles of an adult and of one month-old baby undoubtedly related to the fact that the child’s muscular belly is longer in relation to the tendon. The histotopography of intramuscular nerves on total transverse sections of antagonistic muscles was studied: flexor and extensor digitorum longus, longus flexor and extensor of the big toe, and also the spectrum of myelin fibers contained in these nerves in a one-month-old baby and an adult was investigated. On histotopographic sections of the extensor digitorum longus nerve in a one-month-old baby, thick-diameter myelin fibers are absent, whereas in the long finger flexor nerve, on average, they are 0.5%. The number of thin and medium is respectively 8%, 13% and 83.5%, 16%. However, we have determined individual anatomical variability in the location of the vessels in relation to the main nerve trunks, as well as differences in the topography of the nerve in the corresponding muscles. Conclusion. In the nerves of the leg muscles, features were found, both in quantitative and qualitative composition of the conductors forming them; in the nerves of the flexor muscles, the composition of the nerve fibers is more diverse (with a slight predominance of the number of medium, thick and very thick fibers), which is associated with the peculiarity of their functions; in adulthood, the % ratio in the spectrum of myelin fibers in the nerves of the lower leg changes significantly

The problem in this study is that volleyball extracurricular students at SMP Negeri 6 Lubuklinggau City still have jumps and punches in the weak category, this is due to the weak power of the students' leg muscles which causes the smash to be performed less than optimal. The research objective was to determine whether there was a relationship between the explosive power of the leg muscles and the smash ability of volleyball players at SMP Negeri 6 Lubuklinggau City. The variables of this study were the leg muscle explosive power as the independent variable, and the smash ability was the dependent variable. This type of research is correlational research. This research was conducted on 14 male volleyball extracurricular students at SMP Negeri 6 Lubuklinggau City. The instrument for collecting the explosive power of the leg muscles used the vertical jump test and the smash used the smash ability test. The data analysis technique used the product moment correlation formula. The results of the study showed that there was a relationship between the leg muscle explosive power (x) and the volleyball smash ability (y), the calculation result was rxy = 0.55 from this value can be categorized as moderate. The results stated that there was a significant relationship between the explosive power of leg muscles on the smash ability of volleyball extracurricular students at SMP Negeri 6 Lubuklinggau City, this was stated based on hypothesis testing where t hit = 2.280 > t tab = 2.178.

Stability training in the presence of perturbations is an effective means of increasing muscle strength, improving reactive balance performance, and reducing fall risk. We investigated the effects of perturbations induced by an unstable surface during single-leg landings on the mechanical loading and modular organization of the leg muscles. We hypothesized a modulation of neuromotor control when landing on the unstable surface, resulting in an increase of leg muscle loading. Fourteen healthy adults performed 50 single-leg landings from a 30 cm height onto two ground configurations: stable solid ground (SG) and unstable foam pads (UG). Ground reaction force, joint kinematics, and electromyographic activity of 13 muscles of the landing leg were measured. Resultant joint moments were calculated using inverse dynamics and muscle synergies with their time-dependent (motor primitives) and time-independent (motor modules) components were extracted via non-negative matrix factorization. Three synergies related to the touchdown, weight acceptance, and stabilization phase of landing were found for both SG and UG. When compared with SG, the motor primitive of the touchdown synergy was wider in UG (p &lt; 0.001). Furthermore, in UG the contribution of gluteus medius increased (p = 0.015) and of gastrocnemius lateralis decreased (p &lt; 0.001) in the touchdown synergy. Weight acceptance and stabilization did not show any statistically significant differences between the two landing conditions. The maximum ankle and hip joint moment as well as the rate of ankle, knee, and hip joint moment development were significantly lower (p &lt; 0.05) in the UG condition. The spatiotemporal modifications of the touchdown synergy in the UG condition highlight proactive adjustments in the neuromotor control of landings, which preserve reactive adjustments during the weight acceptance and stabilization synergies. Furthermore, the performed proactive control in combination with the viscoelastic properties of the soft surface resulted in a reduction of the mechanical loading in the lower leg muscles. We conclude that the use of unstable surfaces does not necessarily challenge reactive motor control nor increase muscle loading per se. Thus, the characteristics of the unstable surface and the dynamics of the target task must be considered when designing perturbation-based interventions.

This study aims to determine the relationship between limb muscle explosive power and the long jump ability of STKIP-PGRI Lubuklinggau students. This research is a correlational study. The population in this study was the 3rd semester of Physical Education and Health students in the 2020 Academic Year STKIP-PGRI Lubuklinggau. The sample used is 30 students. The research method used is correlation, with data collection techniques using tests and measurements. The instrument for measuring the explosive power of the leg muscles uses the standing broud jump test and for the long jump ability using the long jump test. The data analysis technique uses normality, linearity, and product moment correlation tests using SPSS (Statistical Program For Social Science) for windows software. The results showed that: There was a significant relationship between the explosive power of the leg muscles and the long jump ability of the Physical Education students at STKIP-PGRI Lubuklinggau, with the value of rcount = 0.544 > r table = 0.361. With the contribution of leg muscle explosive power to the long jump ability of the 3rd semester physical education and health sector students in the 2020 Academic Year of STKIP-PGRI Lubuklinggau, amounting to 29.6%. Then the alternative hypothesis is accepted.

To ensure locomotion and body stability, the active role of muscle contractions relies on a stereotyped muscle pattern set in place during development. This muscle patterning requires a precise assembly of the muscle fibers with the skeleton via a specialized connective tissue, the tendon. Like in vertebrate limbs, Drosophila leg muscles make connections with specific long tendons that extend through different segments. During the leg disc development, cell precursors of long tendons rearrange and collectively migrate to form a tube-shaped structure. A specific developmental program underlies this unique feature of tendon-like cells in the Drosophila model. We provide for the first time a transcriptomic profile of leg tendon precursors through fluorescence-based cell sorting. From promising candidates, we identified the Krüppel-like factor Dar1 as a critical actor of leg tendon development. Specifically expressed in the leg tendon precursors, loss of dar1 disrupts actin-rich filopodia formation and tendon elongation. Our findings show that Dar1 acts downstream of Stripe and is required to set up the correct number of tendon progenitors.