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Öğe A comparison of electromyography techniques: surface versus intramuscular recording(SPRINGER, ONE NEW YORK PLAZA, SUITE 4600 , NEW YORK, NY 10004, UNITED STATES, 2024) Karacan, İlhan; Türker, Kemal SıtkıThis review is a comprehensive guide for electromyography (EMG) researchers, providing a comparison of skin EMG recording (surface EMG: sEMG and high-density sEMG: HD-sEMG) and intramuscular EMG recording (multi-motor unit-MMU and single motor unit electromyography-SMU). We delve into the nuances of techniques, highlighting their strengths and limitations in quantifying muscle activation during dynamic and static conditions. We frst examine how EMG signals change with time, focussing on the interplay between motor unit synchronisation and signal amplitude. The review then explores the impact of electrode placement on signal quality. We further discuss the challenges of signal cancellation, crosstalk from neighbouring muscles, and motion artifacts, which can signifcantly afect signal integrity. Finally, we address the temporal changes in electrode impedance and its implications for data interpretation. Our analysis proposes that specifc research objectives should guide the choice amongst sEMG, HD-sEMG, SMU and MMU. MMU, which records the peak counts of individual motor unit action potentials from a localised muscle area, is particularly suited for studying deep or small muscles during static and dynamic activities. Its high sensitivity to motor unit recruitment and discharge rates minimises the impact of factors such as signal cancellation and motion artefacts. Conversely, sEMG is well-suited for short-duration, isometric assessments of large, superfcial muscles. HD-sEMG helps study single motor unit properties under isometric conditions. SMU is particularly suited for studying neuronal networks between stimulated sites and motor neurons. This review aims to provide researchers with the information to select the most appropriate EMG technique for their investigations.Öğe Brief skin cooling modulates the refexes generated by whole‑body vibration(SPRINGER, ONE NEW YORK PLAZA, SUITE 4600 , NEW YORK, NY 10004, UNITED STATES, 2025) Kalaoğlu, Eser; Alayoğlu, Orhun; Sezikli, Selim; Atasoy, Mücahit; Türker, Kemal Sıtkı; Karacan, İlhanBackground Whole-body vibration (WBV) is a popular exercise method known for its neuromuscular benefts, though the underlying mechanisms remain unclear. WBV activates distinct refexes based on vibration amplitude and voluntary muscle activity: low-amplitude vibration or voluntary contraction typically triggers the tonic vibration refex (TVR), whereas highamplitude vibration or quiet standing activates the bone myoregulation refex (BMR). Muscle spindles, which are sensitive to sympathetic input, may exhibit increased responsiveness to vibration during brief skin cooling. Objectives This study investigated the refex mechanisms activated by WBV during quiet standing and their modulation by skin cooling. Methods Thirty healthy young adults participated. The latency of the soleus TVR, induced by Achilles tendon vibration, and the latency of the soleus BMR, induced by WBV, were measured. These assessments were repeated during the cold pressor test (CPT), involving left-hand immersion in cold water. Results The soleus TVR latency was 36.2 ±5.1 ms, while the soleus BMR latency was 40.4 ±5.0 ms. During CPT, Achilles tendon vibration latency remained unchanged (36.2 ±5.7 ms, p= 0.319). However, the WBV-induced refex latency with CPT (36.0 ±6.1 ms, p< 0.0001) was signifcantly shorter than the soleus BMR latency and aligned with the TVR latency (p= 0.711). Conclusion WBV activates BMR in a quiet standing position, but with skin cooling, the TVR predominates, likely due to heightened spindle sensitivity. These fndings ofer valuable insights into developing targeted WBV programs.Öğe Enhancing motor performance through brief skin cooling: exploring the role of enhanced sympathetic tone and muscle spindle sensitivity(SPRINGER, ONE NEW YORK PLAZA, SUITE 4600 , NEW YORK, NY 10004, UNITED STATES, 2025) Çetin, Mert; Kökçe, Mustafa; Karaoğlu, Ayşe; Kalaoğlu, Eser; Kibar, Halime; Sezikli, Selim; Özkan, Mehmet; Türker, Kemal Sıtkı; Karacan, İlhanBackground Although brief skin cooling (BSC) is widely used in sports medicine and rehabilitation for its positive efects on motor performance, the mechanism underlying this motor facilitation efect remains unclear. Objectives To explore the hypothesis that BSC enhances muscle force generation, with cold-induced sympathetic activation leading to heightened muscle spindle sensitivity, thereby contributing to this efect. Methods The study involved two experiments. Experiment 1 included 14 healthy volunteers. Participants submerged their hand in ice water for 3 min. Sympathetic activity was measured via heart rate (HR), muscle force generation was assessed through plantar fexor strength during maximum voluntary contraction (MVC), and cortical contribution to force generation via the volitional wave (V-wave) with and without the cold pressor test (CPT). Experiment-2 involved 11 healthy volunteers and focused on muscle spindle sensitivity and Ia synapse efcacy, assessed using soleus T-refex and H-refex recordings before, during, and after CPT. Results Experiment 1 showed signifcant increases in HR (7.8%), MVC force (14.1%), and V-wave amplitude (93.4%) during CPT compared to pre-CPT values (p=0.001, p=0.03, and p=0.001, respectively). In Experiment-2, hand skin temperature signifcantly decreased during CPT and remained lower than pre-CPT after 15 min (p<0.001). While H-refex and background EMG amplitudes remained unchanged, T-refex amplitude (113.7%) increased signifcantly during CPT and returned to pre-CPT values immediately afterward (p<0.001). A strong correlation was also observed between HR and T-refex amplitude (r=0.916, p=0.001). Conclusion BSC enhances muscle spindle sensitivity via the sympathetic nervous system, promoting more signifcant muscle force generation. The method used in this study can be safely applied in clinical practice.Öğe Evaluation of minimum pinch force while holding in fbromyalgia patients(SPRINGER LONDON LTD, 236 GRAYS INN RD, 6TH FLOOR, LONDON WC1X 8HL, ENGLAND, 2025) Zincirci, Dilara Ekici; İlbeği, Sultan; Çakır, Esin; Atar, Sevgi; Demirhan, Esma; Aydın, Tuğrul; Türker, Kemal Sıtkı; Karacan, İlhan; Kuru, ÖmerObjective This study aimed to investigate the relationship between the minimum pinch force applied during object carrying and physical fatigue in patients with fbromyalgia. For this purpose, the study evaluated the association between the minimum and maximum pinch forces exerted while carrying a weight and both isokinetic muscle strength and the isokinetic fatigue index. Methods One hundred eight (54 FMS/54 healthy) women participated. Pinch force was measured with a force sensor, and wrist fexor/extensor strength and fatigue index were evaluated using an isokinetic dynamometer at 180°/s. Results Minimum pinch force did not difer signifcantly between groups, but maximum pinch force was higher in healthy subjects (p=0.011). Wrist fexor and extensor strength were substantially lower in FMS (p<0.001 for both). Fatigue index was lower in FMS, but diferences were not statistically signifcant (p=0.05, p=0.06). In FMS patients, the minimum pinch force correlated with wrist fexor and extensor fatigue, but no correlation was found in controls. Conclusions Our research shows that the minimum pinch force exerted by women with FMS is not diferent from that exerted by healthy women, but the maximum pinch force is lower. Muscle performance tests measured by isokinetic dynamometry may help assess physical fatigue in FMS patients. Signifcance Although women with FMS can match their healthy peers in minimum pinch force, their lower maximum force may be the main cause of the fatigue they experience during daily activities.Öğe Exploring neuronal mechanisms of osteosarcopenia in older adults(Wiley, 2024) Karacan, İlhan; Türker, Kemal SıtkıUntil recently, research on the pathogenesis and treatment of osteoporosis and sarcopenia has primarily focused on local and systemic humoral mechanisms, often overlooking neuronal mechanisms. However, there is a growing body of literature on the neuronal regulation of bone and skeletal muscle structure and function, which may provide insights into the pathogenesis of osteosarcopenia. This review aims to integrate these neuronal regulatory mechanisms to form a comprehensive understanding and inspire future research that could uncover novel strategies for preventing and treating osteosarcopenia. Specifically, the review explores the functional adaptation of weight-bearing bone to mechanical loading throughout evolutionary development, from Wolff's law and Frost's mechanostat theory to the mosaic hypothesis, which emphasizes neuronal regulation. The recently introduced bone osteoregulation reflex points to the importance of the osteocytic mechanoreceptive network as a receptor in this neuronal regulation mechanism. Finally, the review focuses on the bone myoregulation reflex, which is known as a mechanism by which bone loading regulates muscle functions neuronally. Considering the ageing-related regressive changes in the nerve fibres that provide both structural and functional regulation in bone and skeletal muscle tissue and the bone and muscle tissues they innervate, it is suggested that neuronal mechanisms might play a central role in explaining osteosarcopenia in older adults. image Abstract figure legend The mechanosensitive osteocytic network within the bone matrix acts as a receptor and plays a crucial role in the functional adaptation of bone to mechanical loading. Through mechanotransduction, osteocytes convert mechanical impulses into electrical signals, which are transmitted via afferent nerves to sympathetic preganglionic neurons in the spinal cord and then to ganglionic neurons. Neuropeptides released from postganglionic sympathetic efferent nerves regulate bone formation and resorption processes. Additionally, osteocytes regulate skeletal muscle function by activating motor neurons in the spinal cord via afferent nerves. Disruption of this neuronal regulation mechanism can lead to bone loss and sarcopenia. imageÖğe Inhibitory kinesiotaping has no effect on post-stroke spasticity: Prospective, randomised, controlled study(Elsevier, 2024) Zincirci, Dilara Ekici; Yurttutmus, Zeynep; Türker, Kemal Sıtkı; Karacan, İlhanObjective: Motor neuron pool activity is high in spasticity. The effect of inhibitory kinesiotaping (KT) on spasticity is unclear. The aim of this study is to investigate the effect of inhibitory KT on spasticity after stroke. Methods: Fifty stroke patients with ankle plantarflexor spasticity were randomised to intervention (27) and control (23) groups. Inhibitory KT was applied to the triceps surae muscle in the intervention group and sham KT to the Achilles tendon in the control group. Inhibitory and sham KT were applied for 72 h with a combined conventional rehabilitation programme. Spasticity was assessed at baseline and 72 h after KT using three instruments: Modified Ashworth Scale (MAS), Homosynaptic Post -Activation Depression (HPAD) reflecting the level of motor neuron pool activity, and joint torque as a measure of resistance to passive ankle dorsiflexion. Results: The baseline MAS score, HPAD levels and dorsiflexion torque of the two groups were not significantly different. The change in MAS score was -3.7 +/- 17.5 (p = 0.180) in the intervention group and 3.6 +/- 33.3 (p = 0.655) in the control group. The change in dorsiflexion torque was -0.3 +/- 16.1 kg m (p = 0.539) in the intervention group and 8.0 +/- 24.1 kg m (p = 0.167) in the control group. The change in mean HPAD was 8.7 +/- 34.7 (p = 0.911) in the intervention group and 10.1 +/- 41.6 (p = 0.609) in the control group. Conclusions: The present study showed that inhibitory KT has no antispastic effect in stroke patients.Öğe A new method to determine stretch reflex latency(WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ, 2021) Topkara, Betilay; Aydın, Tuğba; Çorum, Mustafa; Karaoğlu, Ayşe; Ekici Zincirci, Dilara; Buğdaycı, Derya S.; Öneş, Kadriye; Paker, Nurdan; Kesiktaş, Nur; Karacan, İlhan; Türker, Kemal SıtkıIntroduction/Aims: Motion artifact signals (MASs) created by the relative movement of intramuscular wire electrodes are an indicator of the mechanical stimulus arrival time to the muscle belly. This study proposes a method that uses wire electrodes as an intramuscular mechanosensor to determine the stretch reflex (SR) latency without lag time. Methods: Gastrocnemius SR was induced by tendon tap, heel tap, and forefoot tap. The MASs recorded by intramuscular wire electrodes were extracted from background electromyographic activity using the spike-triggered averaging technique. Simultaneous recordings were obtained from multiple sites to validate the MAS technique. Results: Using intramuscular wire electrodes, the MASs were successfully determined and extracted for all stimulus sites. In the records from the rectus femoris, MASs were also successfully extracted; thus, the reflex latency could be calculated. Discussion: Wire electrodes can be used as an intramuscular mechanosensor to determine the mechanical stimulus arrival time to the muscle belly.Öğe The reflex mechanism underlying the neuromuscular effects of whole-body vibration: Is it the tonic vibration reflex?(JMNI, 7 SPILIADOU SQ, NAFPLION 21 100, GREECE, 2022) Çorum, Mustafa; Topkara, Betilay; Kökçe, Mustafa; Özkan, Mehmet; Bucak, Ömer Faruk; Aytüre, Lütfiye; Karacan, İlhan; Türker, Kemal SıtkıObjectives: Whole-body vibration (WBV) is applied to the sole of the foot, whereas local mechanical vibration (LMV) is applied directly to the muscle or tendon. The time required for the mechanical stimulus to reach the muscle belly is longer for WBV. Therefore, the WBV-induced muscular reflex (WBV-IMR) latency may be longer than the tonic vibration reflex (TVR) latency. The aim of this study was to determine whether the difference between WBV-IMR and TVR latencies is due to the distance between the vibration application point and the target muscle. Methods: Eight volunteers participated in this study. The soleus reflex response was recorded during WBV, LMVs, and tendon tap. LMVs were applied to the Achilles tendon and sole of the foot. The latencies were calculated using the cumulative averaging technique. Results: The latency (33.4±2.8 ms) of the soleus reflex induced by the local foot vibration was similar to the soleus TVR latency (30.9±3.2 ms) and T-reflex (32.0±2.4 ms) but significantly shorter than the latency of the soleus WBV-IMR (42.3±3.4 ms) (F(3,21)=27.46, p=0.0001, partial ?2=0.797). Conclusions: The present study points out that the neuronal circuitries of TVR and WBV-IMR are different.
