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Are the mechanical properties of Achilles tendon altered in CrossFit athletes? Reliability and accuracy of myotonometry

Szajkowski Sebastian, Dwornik Michał, Pasek Jarosław, Zajączkowski Mateusz, Cieślar Grzegorz

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 2

103--113

EN

Tendons adapt to loads affecting them by changing tendons’ mechanical and morphological properties. The aim of the study was to investigate the influence of involvement in sport activities in the form of CrossFit training by individuals of different age upon the mechanical properties of Achilles tendon. Methods: 231 people participated in the study. One group consisted of subjects who trained CrossFit as amateurs, the other group comprised subjects who were not physically active. Achilles tendon was studied for various positions of the ankle joint: 0° DF/PF, 10° DF, 20° DF, 20° PF and 40° PF. The following mechanical and viscoelastic tendon properties were measured using MyotonPRO: frequency [Hz], stiffness [N/m], decrement [log], relaxation time [ms] and creep [De]. The results have been compared in reference to physical activity, BMI, age and length of training history. Results: Both the tension and stiffness increased with degree of Achilles tendon stretching and decreased as it contracted. Higher values have been noted in the group of people in training and with higher BMI values. The elasticity of Achilles tendon decreased with plantar flexion increase. Lower elasticity has been recorded in the group in training and with higher BMI. No significant influence of age and length of training history upon the parameters achieved has been noted. Conclusions: The specificity of CrossFit training and accompanying mechanical load result in development of adaptation changes in Achilles tendon, in the form of its higher tone/tension and stiffness, as well as lower elasticity.

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Influence of number of records on reliability of myotonometric measurements of muscle stiffness at rest and contraction

Marusiak J., Jarocka E., Jaskólska A., Jaskólski A.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 3

123--131

EN

The aim of this study was to determine an effect of myotonometric records’ number on stiffness measurements’ reliability in muscles at rest and contraction. Methods: Muscle stiffness was measured using Myoton-3 device. Twenty records were taken for: (i) biceps (BB) and triceps brachii (TB) at rest and for BB at 10% of maximal voluntary contraction (MVC) in healthy elderlies (HE) and in Parkinson’s disease patients (PD); and (ii) brachioradialis (BR) at rest and at 25, 50 and 80% MVC in healthy young (HY) subjects. Also, in HY group, the 3-records mode was used for BR’s measurements at maximal contraction. Each measurement taken with 20-records was classed into five records groups: the whole 20- and the first 15-, 10-, 5- and 3-records. Test-retest reliability for these records groups was analyzed. Results: In HE and PD group measurements’ reliability was excellent for all groups of records (20–3 records). In HY group, for the five groups of records taken at rest and submaximal levels of contraction (25, 50 and 80% MVC) the measurements reliability: (i) was mostly excellent or rarely average; and (ii) only in one per three 50% MVC conditions was unacceptable, i.e., for the 3-records group. The reliability of 3-records mode measurements at maximal contraction were unacceptable. Conclusions: Reliable myotonometric stiffness measurements in muscles at rest and during submaximal contractions can be achieved with less than 20 records (15, 10, 5 records) and even for the most of measurements with 3 records in HY and HE as well as in the PD patients. Myotonometric stiffness measurements with 3-records mode during maximal contraction were not reliable.

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Influence of dopaminergic treatment on resting elbow joint angle control mechanisms in patients with Parkinson’s disease – a preliminary report

Marusiak J., Jaskólska A., Budrewicz S., Koszewicz M., Andrzejewska R., Kisiel-Sajewicz K., Jaskólski A.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 4

75--82

EN

Heightened tonic stretch reflex contributes to increased muscle tone and a more-flexed resting elbow joint angle (EJA) in patients with Parkinson’s disease (PD). Dopaminergic medication restores central nervous system (CNS) functioning and decreases resting muscle electrical and mechanical activities. This study aimed to evaluate the effects of dopaminergic medication on parkinsonian rigidity, resting EJA, resting electrical activity (electromyography, EMG) and mechanical properties (myotonometry, MYO) of elbow flexor muscles and the associations of EJA with these muscles resting electrical activity and mechanical properties in PD patients. We also evaluated a relationship between dopaminergic treatment dose and these outcome measures values. Methods: Ten PD patients (age 68 ± 10.1 years; body mass 70 ± 16.8 kg; height 162 ± 6.6 cm; illness duration 9 ± 4.5 years) were tested during medication on- and off-phases. Resting EJA, myotonometric muscle stiffness (S-MYO) and root mean square electromyogram amplitude (RMS-EMG) were recorded from relaxed biceps brachii and brachioradialis muscles. Based on the above parameters, we also calculated the EJA/S-MYO ratio and EJA/RMS-EMG ratio. Parkinsonian rigidity was assessed using the motor section of the Unified Parkinson’s Disease Rating Scale. Results: EJA, EJA/S-MYO ratio, and EJA/RMS-EMG ratio were increased and S-MYO, RMS-EMG, and parkinsonian rigidity were decreased during the medication on-phase compared with the off-phase. In addition, the dopaminergic treatment dose was negatively correlated with S-MYO and RMS-EMG, and positively correlated with EJA/SMYO and EJA/RMS-EMG ratios. Conclusions: We conclude that dopaminergic medication-induced improvements in resting elbow joint angle in tested patients with PD are related to changes in their muscle electrical and mechanical properties.