Search results for "ultraääni"
showing 10 items of 51 documents
How Do Infanticidal Male Bank Voles (Myodes glareolus) Find the Nest with Pups?
2016
Infanticide, the killing of conspecific young, occurs in most mammal species, like in our study species, the bank vole (Myodes glareolus). Infanticide by adult males is regarded as a strong factor affecting recruitment of young into population. It is considered as an adaptive behaviour, which may increase male fitness via resource gain or an increased access to mates. When an intruder is approaching the nest, the mother should not be present, as her nest guarding is very aggressive and successful. Pups use ultrasonic vocalisation to call their mother when mother leaves nest for foraging but it is not know which cues do infanticidal males use to find the nest with vulnerable pups to commit i…
Simple Muscle Architecture Analysis (SMA): An ImageJ macro tool to automate measurements in B-mode ultrasound scans
2020
In vivo measurements of muscle architecture (i.e. the spatial arrangement of muscle fascicles) are routinely included in research and clinical settings to monitor muscle structure, function and plasticity. However, in most cases such measurements are performed manually, and more reliable and time-efficient automated methods are either lacking completely, or are inaccessible to those without expertise in image analysis. In this work, we propose an ImageJ script to automate the entire analysis process of muscle architecture in ultrasound images: Simple Muscle Architecture Analysis (SMA). Images are filtered in the spatial and frequency domains with built-in commands and external plugins to hi…
Biplanar ultrasound investigation of in vivo Achilles tendon displacement non-uniformity
2019
The Achilles tendon is a common tendon for the medial and lateral gastrocnemius and soleus muscles. Non‐uniform Achilles tendon regional displacements have been observed in vivo which may result from non‐uniform muscle loading and intratendinous shearing. However, prior observations are limited to the sagittal plane. This study investigated Achilles tendon tissue displacement patterns during isometric plantarflexor contractions in the coronal and sagittal planes. Fourteen subjects (5 female, 9 male, 26 ± 3 year) performed maximal isometric plantarflexor contractions with the knee in full extension and flexed to 110°. An ultrasound transducer positioned over the free Achilles tendon collecte…
Muscle-tendon architecture in Kenyans and Japanese : Potential role of genetic endowment in the success of elite Kenyan endurance runners
2022
Aim The specificity of muscle-tendon and foot architecture of elite Kenyan middle- and long-distance runners has been found to contribute to their superior running performance. To investigate the respective influence of genetic endowment and training on these characteristics, we compared leg and foot segmental lengths as well as muscle-tendon architecture of Kenyans and Japanese males (i) from infancy to adulthood and (ii) non-athletes versus elite runners. Methods The 676 participants were divided according to their nationality (Kenyans and Japanese), age (nine different age groups for non-athletes) and performance level in middle- and long-distance races (non-athlete, non-elite and elite …
Achilles tendon stiffness is unchanged one hour after a marathon
2012
Overuse-induced injuries have been proposed as a predisposing factor for Achilles tendon (AT) ruptures. If tendons can be overloaded, their mechanical properties should change during exercise. Because there data are lacking on the effects of a single bout of long-lasting exercise on AT mechanical properties, the present study measured AT stiffness before and after a marathon. AT stiffness was determined as the slope of the force–elongation curve between 10 and 80% of maximum voluntary force. AT force–elongation characteristics were measured in an ankle dynamometer using simultaneous motion-capture-assisted ultrasonography. Oxygen consumption and ankle kinematics were also measured on a trea…
The reliability of measuring medial gastrocnemius muscle-tendon unit lengths during gait
2021
Background Ultrasound imaging combined with 3D motion analysis allows for in-vivo assessment of muscle-tendon unit lengths during gait. The clinical relevance of analysing the medial gastrocnemius (MG) and Achilles muscle-tendon junction (MTJ), MG mid-muscle belly fascicles (FAS) and muscle thickness was shown. However, their reliability error estimations over the gait cycle is unknown. Research question What are the intra- and inter-session errors associated with extracting MG belly, thickness, FAS and tendon lengths using ultrasound during gait in healthy participants? Methods 3D gait analysis was carried out in ten healthy adults as they walked on an instrumented treadmill at a comfortab…
Fascicle-tendon interaction in v2 skate cross-country skiing : a case study
2015
Venymis-lyhenemis –sykli (SSC) on laajalti tutkittu liha-jänne -kompleksin (MTU) toimintamalli ihmisen liikkumisessa. Jotta SSC toiminta voidaan ymmärtää, lihaksen toiminta tulee mitata ultraäänen (US) avulla. Aiemmin yksi tutkimus on käsitellyt MTU:n toimintaa hiihdon aikana perinteisellä hiihtotavalla (Ishikawa, Sano et al. 2010). Tämän tutkimuksen tavoitteena on tarjota ainutlaatuinen kokeellinen tulos MTU:n toiminnasta vapaan hiihdon V2- tekniikan aikana, sekä tarjota suosituksia tulevaa tutkimusta varten. Tutkimuksessa yksi kokenut hiihtäjä suoritti protokolla Vuokatin hiihtotunnelissa. Protokolla koostui kahdesta eri mittauskerrasta, joiden välissä suoritettiin 20 km mittainen hiihtok…
Neuromuscular mechanics and hopping training in elderly.
2014
Purpose The present study examined the effects of repetitive hopping training on muscle activation profiles and fascicle–tendon interaction in the elderly. Methods 20 physically active elderly men were randomly assigned for training (TG) and control groups (CG). TG performed supervised bilateral short contact hopping training with progressively increasing training volume. Measurements were performed before the training period (BEF) as well as after 2 weeks (2 W) and 11 weeks (11 W) of training. During measurements, the gastrocnemius medialis–muscle (GaM) fascicle and its outer Achilles tendon length changes during hopping were examined by ultrasonography together with electromyographic (EMG…
Coded excitation speeds up the detection of the fundamental flexural guided wave in coated tubes
2016
The fundamental flexural guided wave (FFGW) permits ultrasonic assessment of the wall thickness of solid waveguides, such as tubes or, e.g., long cortical bones. Recently, an optical non-contact method was proposed for ultrasound excitation and detection with the aim of facilitating the FFGW reception by suppressing the interfering modes from the soft coating. This technique suffers from low SNR and requires iterative physical scanning across the source-receiver distance for 2D-FFT analysis. This means that SNR improvement achieved by temporal averaging becomes time-consuming (several minutes) which reduces the applicability of the technique, especially in time-critical applications such as…
Viscoelastic properties of the Achilles tendon in vivo
2013
It has been postulated that human tendons are viscoelastic and their mechanical properties time-dependent. Although Achilles tendon (AT) mechanics are widely reported, there is no consensus about AT viscoelastic properties such as loading rate dependency or hysteresis, in vivo. AT force-elongation characteristics were determined from 14 subjects in an ankle dynamometer at different loading rates using motion capture assisted ultrasonography. AT stiffness and elongation were determined between 10 – 80% of maximum voluntary contraction (MVC) force at fast and slow loading rates. As subjects were unable to consistently match the target unloading rate in the slow condition, AT hysteresis was on…