Search Results (57)

Background: Early detection of developmental disorders in infants is an important topic for scientists and clinicians, but above all for children and their families. Early detection of changes in the mechanical properties of muscles is crucial for starting therapeutic processes. This study aims to fill the research gap regarding the use of myotonometry in the infant patient group (aged 0–3 months). The study aimed to evaluate the test–retest repeatability of myotonometric measurements in infants at three time points, with particular attention to potential age-related differences. Methods: The study group consisted of healthy newborns born from physiological pregnancies with an Apgar score of 8–10 points. The studies began on the 1st–3rd day of life and lasted until the 12th week in cycles every 6 weeks. Results: In the study conducted on the 1st–3rd day of life, the repeatability of the studied parameters can be described as moderate (muscle tone, elasticity, relaxation, and creep) or poor (stiffness). Measurements conducted in the 6th week of life show high repeatability of muscle stiffness and elasticity or moderate repeatability of muscle tone, creep, and relaxation time. Measurements in the 12th week of life of the infants may be considered as high repeatability of muscle tone, stiffness, relaxation time, and the creep parameter, and moderate muscle elasticity. Conclusions: The study demonstrated the usefulness of using myotonometric measurement for infants from the 6th and 12th week of age in the studied parameters, confirmed by the high repeatability of measurements. Whereas in the group of newborns aged 1–3 days, the repeatability of all analyzed parameters can be described as moderate or low. Full article

Background: Tibial pilon fractures are complex injuries frequently associated with persistent functional impairment, even after successful surgical fixation. While previous studies have reported deficits in muscle strength and balance, little is known about the side-to-side variations in intrinsic biomechanical and viscoelastic muscle properties following surgery. Objectives: This study aimed to compare the biomechanical and viscoelastic properties of ankle periarticular muscles between the affected and non-affected limbs in patients with surgically treated unilateral tibial pilon fractures. A secondary objective was to evaluate the relationship between intrinsic muscle properties and isometric muscle force. Methods: A total of 39 subjects with unilateral surgically treated tibial pilon fractures were evaluated after fracture healing. Myotonometric assessment was performed to evaluate muscle mechanical parameters, including tone (frequency), stiffness, and elasticity (decrement), as well as viscoelastic properties, including relaxation time and creep, in the tibialis anterior, peroneus longus, medial gastrocnemius, and lateral gastrocnemius muscles. Isometric muscle force of ankle dorsiflexors and plantar flexors was measured using a handheld dynamometer. Side-to-side comparisons and Pearson correlation analyses were performed. Results: The affected limb showed significantly reduced ankle range of motion in all planes and significantly lower isometric muscle force in both the dorsiflexors (p = 0.0002) and the plantar flexors (p = 0.0066). Stiffness was significantly higher in the medial (p = 0.038) and lateral gastrocnemius (p = 0.045) muscles on the affected side. Decrement was significantly increased (indicating reduced elasticity) in the peroneus longus (p = 0.021). No significant differences were observed for tone, relaxation time, or creep. Conclusions: Myotonometry revealed increased stiffness in the gastrocnemius muscles and reduced elasticity in the peroneus longus on the operated side compared with the non-affected limb. Tone and viscoelastic properties did not differ significantly between sides. However, tone, stiffness, and elasticity were significantly correlated with muscle force, indicating a relationship between intrinsic muscle mechanical properties and force production after tibial pilon fracture surgery. Full article

Background: We assessed the effects of a 6-week, low-volume Nordic hamstring exercise (NHE) intervention on hamstring flexibility, muscle mechanical properties and eccentric and isometric isokinetic knee flexion strength in recreationally active adults. Methods: Eighteen recreationally active adults were randomized into an NHE intervention group (IG; n = 9; females/males: 3/6; mean ± SD, age: 24.1 ± 1.3 years) and control group (CG; n = 9; females/males: 5/4; mean ± SD, age: 23.5 ± 1.8 years). The NHE intervention involved a progressive, supplementary training program performed initially one (weeks 1 and 2) and then two times per week over a 6-week period. The number of repetitions per session increased from 15 to 36 repetitions/week. The CG maintained their usual exercise routine over the same period. Standard goniometry, myotonometry, and isokinetic dynamometry (60°/s) were used to measure hamstring flexibility, muscle properties and isometric and eccentric isokinetic strength prior to and five days following the intervention. Results: The Linear Mixed Methods analysis identified a significant group × time interactions for isometric torque (IG: +5% vs. CG: −12%, p = 0.022) and flexibility (IG: +1% vs. CG: +7%, p = 0.023). Peak eccentric torque (IG: +7% vs. CG: −7%, p = 0.053) and muscle mechanical properties remained unchanged over the intervention period. Conclusions: Six weeks of low-volume NHE training marginally improved isometric and eccentric hamstring strength in recreationally active adults without changing hamstring flexibility or mechanical properties. The findings may have important implications for performance enhancement and hamstring injury risk reduction during high-intensity recreational sports. Full article

Background/Objectives: Abnormal muscle tone and impaired motor control commonly limit gait recovery after stroke. Robot-assisted gait training has been introduced to augment conventional rehabilitation; however, its effects on stage-based motor recovery, functional ambulation, and muscle tone during the subacute phase remain unclear. Methods: This prospective, single-center, randomized controlled trial enrolled 30 patients with subacute stroke who received robot-assisted gait training plus conventional rehabilitation (R-BoT Plus group, n = 15) or conventional rehabilitation alone (control group, n = 15) over 4 weeks. The primary outcome was the change in Brunnstrom recovery stage of the lower extremities (BRS-LE). Secondary outcomes included Functional Ambulation Category (FAC), Fugl–Meyer Assessment for the Lower Extremity (FMA-LE), clinical spasticity measures (Modified Ashworth Scale and Modified Tardieu Scale), and muscle mechanical properties (MyotonPRO). Exploratory analyses were conducted to examine the associations between changes in stage-based motor recovery (ΔBRS-LE), functional ambulation (ΔFAC), and MyotonPRO parameters. Within-group changes were assessed using the Wilcoxon signed-rank test. Between-group effects were primarily evaluated using baseline-adjusted ANCOVA with HC3 robust standard errors, with Wilcoxon rank-sum tests on change scores as sensitivity analyses. Associations between changes in clinical outcomes and MyotonPRO parameters were evaluated using Spearman’s rank correlation coefficient (ρ). Results: BRS-LE (p = 0.014) and functional ambulation (p = 0.041) were significantly improved in the R-BoT Plus group. Changes in FMA-LE and clinical spasticity measures did not differ significantly between groups. Quantitative myotonometry revealed selective muscle- and parameter-specific changes. No robust correlations were observed between MyotonPRO parameters and changes in BRS-LE. Conclusions: The addition of robot-assisted gait training to conventional rehabilitation was associated with greater improvements in stage-based lower-limb motor recovery and functional ambulation in patients with subacute stroke. In contrast, cumulative impairment scores and conventional clinical spasticity measures demonstrated limited changes between groups. Quantitative muscle mechanical assessment revealed selective muscle-specific adaptations, supporting its role as a complementary tool for mechanistic characterization rather than as a surrogate marker of motor recovery. Future studies incorporating dose-matched designs and longer follow-up periods are warranted to clarify the independent and long-term effects of robot-assisted gait training. Full article

Context/Objectives: Pectus excavatum (PE), the most common anterior chest wall deformity in children and adolescents, impacts posture and is frequently associated with axial deviations due to biomechanical alterations of the spine and the properties of the involved musculature. Methods: We assessed 35 patients with PE with a Haller index below 3.25, aged between 5 and 17 years, who completed a three months specialized physical exercise program after proper training and instruction by a specialist. All patients were assessed before starting the exercise program and at the end of the treatment. The assessment method used was myotonometry, employing the MyotonPRO device, targeting the trapezius muscle with all three fascicles and the pectoralis major muscle both on the left and the right side, measuring: frequency (Hz), stiffness (N/m), decrement, relaxation time (ms), and the ratio between relaxation time and deformation time (creep). Results: The analysis of myotonometric parameters reveals a pattern of selective adaptation, predominantly involving the left hemibody in most of the groups analyzed, without significant functional imbalances. This asymmetry may reflect either the functional predominance of the left hemibody during participants’ daily activities or increased activation induced by the exercise program; however, by the end of the intervention, bilateral stability was observed in most parameters. Conclusions: A three-month physical exercise program in children and adolescents with PE results in improvements in muscle properties, particularly in the pectoralis major and middle trapezius muscles bilaterally, and contributes to the restoration of functional symmetry, thereby supporting the effectiveness of the exercise program in optimizing neuromuscular control, tissue elasticity, and scapular stability. Full article

Background: Mechanization in olive harvesting has improved productivity but introduced new ergonomic challenges, particularly related to vibration exposure and sustained overhead work. This study investigates the acute and short-term physiological effects of using an electric olive harvester through objective instrumental assessment. Methods: Ten healthy male volunteers performed a standardized 15-min simulated harvesting task using an electric olive harvester. Muscle tone, stiffness, and elasticity of bilateral deltoid, biceps, and triceps were assessed by myotonometry at baseline (T0), immediately post-task (T1), and after 2 h recovery (T2). Infrared thermography evaluated cervical, dorsal, and lumbar skin temperature at the same timepoints. Results: Significant, side-dependent alterations in myotonometric parameters were observed, with marked increases in tone and stiffness of dominant upper-limb muscles and asymmetric adaptations between limbs (p < 0.001, large effect sizes). Infrared thermography revealed significant post-task reductions in skin temperature across spinal regions, with a partial return toward baseline within the 2 h observation window (p < 0.01). These findings describe short-term, task-related thermoregulatory responses following sustained work. Conclusions: Even short-term use of electric olive harvesters induces measurable biomechanical and thermophysiological stress. The integrated use of myotonometry and infrared thermography provides a sensitive, field-adaptable framework for early ergonomic risk detection and prevention of work-related musculoskeletal disorders in agriculture. Full article

Background: The objective of this study was to assess the tension of selected postural muscles during the jaw-sucking movement in four body positions (standing position, all-fours position, lying on front, lying on the side). Material and Methods: The research involved 30 young adults with an average age of 22.6 ± 0.72 years. Suprahyoid, trapezius, gluteus maximus, and gastrocnemius muscles were assessed in all study participants in the standing, kneeling, and belly lying positions (prone position). Measurements were taken twice for each position: once without jaw activity and once with jaw movements simulating sucking. Muscle function was determined by measuring muscle tension using surface electromyography (sEMG). Results: Engaging jaw movements in the prone position resulted in significantly increased tension in the gastrocnemius muscle. In the all-fours position, there was a notable rise in tension in both the gastrocnemius and gluteus maximus muscles. When standing, significantly higher tension was observed in the trapezius and gluteus maximus muscles. In contrast, the side-lying position exhibited no significant changes in muscle tension. Conclusions: The study’s findings suggest that activating jaw function may affect the tone of the gastrocnemius muscle in both prone and quadrupedal positions. In contrast, there were no clear or statistically significant changes observed in the tone of trapezius muscles in either position, while, for the tension of the gluteus medius muscle, variability was shown only in the all-fours position. Full article

Background/Objectives: Neuromuscular functions (NMFs) encompass biomechanical and viscoelastic properties that are essential for coordinated movement and muscular control. While NMFs have been extensively investigated in the lower limb, normative data for the upper extremity remain limited, particularly regarding the interaction between neuromuscular properties, superficial fascia, and body composition. As body composition and fascial characteristics may influence neuromuscular behavior and the interpretation of mechanical measurements, this study aimed to establish reference values for upper limb NMF, analyze dominance-related differences, and investigate the relationship between superficial fascia thickness and body mass composition. Methods: A descriptive, non-experimental study was conducted involving 61 healthy adults (122 upper limbs). Assessments included body composition (bioimpedance), superficial fascia thickness (skinfolds), viscoelastic properties (MyotonPro), and isometric strength (handheld dynamometry). Standardized protocols were applied for all measurements. Comparisons were performed between sexes and between dominant and non-dominant limbs. Correlation analyses explored associations between NMF, adiposity, and fascia parameters. Results: Dominant limbs showed slightly greater strength; however, these differences were not statistically significant. Viscoelastic properties were largely symmetrical between limbs, with minimal dominance-related differences. Clear sex differences were observed: men demonstrated greater strength, lean mass, and increased stiffness, whereas women presented higher skinfold thickness and lower muscle tone. Weak correlations were identified between stiffness, relaxation, and strength, as well as between adiposity and superficial fascia thickness. Greater adipose thickness was associated with lower stiffness values in the triceps (rho= −0304; iC95% 0.041/0.528; p = 0.017). Conclusions: Upper limb neuromuscular properties exhibit high bilateral symmetry, with limb dominance influencing strength. Sex and body composition significantly modulate both viscoelastic and functional parameters. These findings provide normative reference values and highlight the relevance of considering body composition and fascial characteristics when assessing neuromuscular function in clinical and sports contexts. Full article

Background. Cervical spondylosis is a degenerative disorder of the spine, frequently associated with chronic neck pain, reduced mobility, and functional impairment. Patients develop alterations in muscle tone, stiffness, and elasticity, which further contribute to disability. This study aimed to investigate the effects of a 14-day standardized rehabilitation program on the biomechanical and contractile properties of cervical and scapular muscles in patients with cervical spondylosis. Methods. This study used a single-group pre–post observational design on 23 patients (16 women, 7 men; mean age 61.1 ± 14.2 years) diagnosed with cervical spondylosis. All participants completed a standardized rehabilitation treatment that included cervical mobilization, stretching, isometric exercises, scapular stabilization, electrotherapy, ultrasound, thermotherapy, and balneotherapy. Muscle properties were evaluated bilaterally using the MyotonPRO^® device, measuring frequency, stiffness, decrement, relaxation time, and creep. Assessments were performed in a sitting position for the deltoid, upper trapezius and pectoralis major, both at baseline (T0) and after treatment (T1). Handgrip strength was assessed bilaterally with a handheld dynamometer. Results. The deltoid muscle showed a significant reduction in frequency (14.86 → 13.50 Hz, p = 0.034) and stiffness (306.4 → 256.1 N/m, p = 0.014) on the right side, suggesting normalization of tone and passive resistance. The upper trapezius had a significant bilateral decrease in decrement (p < 0.05), reflecting improved elasticity. The pectoralis major displayed the most consistent adaptations, with increased frequency (right side, p = 0.008), improved relaxation bilaterally (p < 0.05), and significant reductions in decrement and creep (p < 0.01). Handheld dynamometry confirmed increased handgrip strength, with a 5.4% improvement on the left side and 7.6% on the right side. Conclusions. In our study measurable changes in muscle parameters were observed following a rehabilitation program in patients with cervical spondylosis. The integration of myotonometry and dynamometry allowed objective assessment of muscle adaptations supporting the clinical value of individualized rehabilitation strategies. Full article

Objective: To test whether inpatient electrical muscle stimulation (EMS) using Russian current (5 kHz carrier, 50 Hz modulation; 4 s ON/6 s OFF) improves mobility and balance in elderly people with chronic cerebral ischaemia. Design: Prospective single-centre controlled observational pilot, embedded in routine inpatient rehabilitation; no concealed randomisation (EMS + standard care; sham EMS + standard care; standard care only (control)). Methods: A single-centre controlled observational study with three groups was conducted (EMS n = 27, control n = 10, sham n = 7) with 3–9 sessions over 2 weeks (20 min; quadriceps and calves). Pre/Post Outcomes: Tinetti (balance/gait), Rivermead Mobility Index, Timed Up and Go (TUG), ankle extensor maximal voluntary force (MVF), stabilography (statokinesiogram path length (L), mean velocity of COP (V), sway area (S), and myotonometry; ANOVA, α = 0.05). Ethics approval and informed consent were obtained. Between-group differences in change scores were evaluated descriptively, and no formal hypothesis-testing was planned. Results: EMS showed significant gains versus control/sham—higher Tinetti total and Rivermead scores, faster TUG, higher MVF, and improved stabilography in the eyes-closed condition (reduced L, V, and S), with good tolerability and no serious adverse events (SAEs). Conclusions: Short-course Russian-current EMS is feasible and associated with clinically meaningful improvements in balance, gait, and strength in elderly patients with chronic cerebral ischaemia; however, larger randomised trials are warranted. Full article

Background and Objectives: This study set out to better understand how posture, spinal level, gender and muscle activation influence the biomechanical properties of the lumbar erector spinae (LES) in healthy young adults. We aimed to measure how these factors influence LES tone, stiffness, and damping using a myotonometry device. Materials and Methods: Thirty healthy young adults (14 males, 16 females; aged 20–25 years) were evaluated at bilateral L3–L5 levels in prone, unsupported sitting, and standing positions, both under relaxed conditions and during submaximal isometric lumbar extension. The myotonometer measured LES tone (Hz), stiffness (N/m), and damping (logarithmic decrement). For each outcome, a mixed-model repeated-measures ANOVA was conducted with Gender as a between-subject factor and Posture, Level, and Action (relaxed vs. contracted) as within-subject factors (Bonferroni-adjusted α = 0.0167). Results: Posture produced the most significant and consistent effects on all properties—stiffness, tone, and damping (p < 0.0167)—with sitting and standing generally increasing stiffness and tone compared to prone, and sitting showing the highest values. Gender significantly impacted stiffness and tone (p < 0.0167), with males showing higher values. Spinal level also significantly influenced damping, stiffness, and tone (all p < 0.0167), with differences more apparent in females. Significant interactions included the influence of Posture × Gender on tone and damping (p < 0.0167), and of Posture × Action on stiffness and tone (p < 0.0167), alongside a strong three-way interaction for Level × Action × Posture across all outcomes, suggesting posture-related responses depend on activation state and spinal level. Conclusions: LES biomechanical properties are strongly affected by posture and further modulated by muscle activation, gender, and spinal level. These results support the creation of posture- and gender-specific reference values and underscore the value of dynamic, posture-specific myotonometer-based assessments for paraspinal muscle evaluation and clinical planning. Full article

Adolescent idiopathic scoliosis (AIS) is a 3D structural deformity of the spine that can cause decreased spinal movement, paraspinal muscle weakness, or chronic pain. Our study aims to evaluate biomechanical and viscoelastic properties of the paravertebral muscles in adolescents with idiopathic S-type scoliosis, static plantar pressure, and stabilometry at the beginning of a physical exercise program and after 3 months. The myotonometry performed by using MyotonPro will determine five parameters (frequency, stiffness, logarithmic decrement, stress relaxation time, and ratio of relaxation time to deformation time). Measurements will be taken at the level of the left/right middle trapezius, left/right lower trapezius, left/right latissimus dorsi, and left/right lumbar erector muscles. Static pressure assessment and stabilometry (length described by the center of pressure, confidence area, and speed described by the center of pressure) will be determined by a PoData device in different testing positions (eyes open, eyes closed, head rotated to the right/left, head tilted to the right/left, and head in hyperextension). We expect to record a difference between the muscles on the concave side and the convex side in terms of myotonometric parameters, as well as differences between the initial and 3-month assessment. We predict an improvement in stabilometric parameters after the 3-month physical exercise program. Full article

Background: Acute alterations in biomechanical and viscoelastic muscle properties provide important insight into early fatigue mechanisms; however, their dependence on specific muscle contraction types remains insufficiently understood. Therefore, the aim of this study was to quantitatively compare the acute effects of eccentric, concentric, isometric, and mixed contractions on the biomechanical and viscoelastic properties of the biceps brachii using myotonometry. Methods: Eighty healthy men aged 40 to 50 years were randomly assigned to four contraction conditions: eccentric, concentric, isometric or mixed concentric-eccentric. Each participant performed four sets of isolated biceps brachii exercise to volitional failure. Myotonometric measurements of tone, stiffness, decrement, relaxation and creep were collected before exercise and after each set. Changes within and between contraction types were analyzed. Results: Muscle responses differed significantly depending on contraction type. Dynamic contractions induced immediate viscoelastic changes, with significant reductions in relaxation time after eccentric (p = 0.027), concentric (p = 0.026), and mixed contractions (p < 0.001), while no changes were observed after isometric contraction (p = 0.285). Stiffness remained stable across all contraction types (p > 0.05). Mixed contractions showed a biphasic response in decrement with a significant effect across series (p = 0.049), identifying decrement as the most sensitive indicator of early fatigue, whereas isometric contraction produced no significant modifications in any parameter. Conclusions: Dynamic muscle work induces rapid and contraction-dependent shifts in viscoelastic properties, whereas stiffness appears resistant to short-term loading. Isometric contractions display minimal mechanical disturbance. Myotonometry proved effective in detecting early fatigue-related changes and decrement may serve as a key marker of short-term muscle adaptation. Full article

Background: Tibial pilon fractures are, in most cases, complex injuries caused by high-energy trauma. This type of fracture requires surgical stabilization and immobilization that impairs ankle function by reducing range of motion, muscle strength, and affecting the mechanical properties of the muscles. Methods: We evaluated 22 patients who required surgery for tibial pilon fractures and 22 age-matched healthy controls. Dynamometry assessed the isometric strength of the dorsiflexors and plantar flexors. Myotonometry of the tibialis anterior, peroneus longus, and medial and lateral gastrocnemius muscles analyzed the muscle tone, biomechanical (stiffness and decrement), and viscoelastic properties (mechanical stress relaxation and ratio of relaxation time to deformation time (creep). Results: Compared to the control group, the patients had significantly decreased isometric strength in both the dorsal flexors and plantar flexors on the affected side. Myotonometric measurements did not reveal significant differences in the tibialis anterior and peroneus longus muscles. Both medial and lateral gastrocnemius muscles exhibited significantly increased frequency and stiffness, and significantly decreased relaxation and creep in patients when compared to the control group. Conclusions: When compared to healthy controls, patients with surgically treated unilateral pilon fracture had a decreased isometric muscle force of ankle dorsiflexors and plantar flexors of both affected and non-affected lower limbs. Myotonometry indicated increased frequency and stiffness, along with decreased values of viscoelastic parameters (stress relaxation time and creep) in the medial and lateral gastrocnemius muscles on both sides. Full article

Background/Objectives: Among women with a history of cesarean section (CS), scar abnormalities are observed in 20–32% of cases. The presence of a scar in the lower abdomen may cause pain, dysmenorrhea, dyspareunia, and postural dysfunction. The aim of the study was to conduct a feasibility study and secondary exploratory analysis of the factors determining scar stiffness and elasticity in women after CS. Methods: The study involved 30 women aged 26 to 45 who had undergone at least one CS no earlier than six months before the start of the study. The following feasibility endpoints were analyzed: recruitment rate, completion rate, protocol deviations, and device usability. Myotonometry was performed to quantify the stiffness and decrement (a parameter that inversely reflects tissue elasticity) of the CS scar. The correlation between stiffness and decrement and age, BMI, time since the las CS, and the number of CSs was assessed. Results: All predefined feasibility criteria were met. Recruitment exceeded the target rate (3.3 participants/week), with a high completion rate (90%). One minor protocol deviation occurred without impact on safety or data integrity. The MyotonPro device showed good usability, with no reported discomfort and successful completion of all measurements. Secondary exploratory correlation analyses suggested a tendency toward a negative correlation between BMI and the stiffness and decrement (indicating increased elasticity) across most scar regions. No consistent correlations were observed between age and the examined scar parameters. Exploratory analyses further indicated a probable positive correlation between time elapsed since the last CS and stiffness and decrement (indicating reduced elasticity), which was observed only in the central region of the scar. The number of cesarean section procedures showed sporadic, region-specific correlations with scar parameters, limited to selected measurement points. Conclusions: These findings suggest that the study design is feasible and acceptable. Future research protocols should also include a comparison with healthy skin in the scar area. Preliminary exploratory analyses suggest a potential influence of BMI and time since last CS on scar stiffness and elasticity. However, due to the limitations of the pilot study, these observations should be considered preliminary and hypothesis-generating and may be used to design future confirmatory studies. Full article