Dawid Łochyński

Introduction: Conflicting findings have been reported about effects of transcutaneous spinal direct current stimulation (tsDCS) on jumping performance, as transabdominal tsDCS was shown to enhance maximum jumping height while spine-shoulder did not. The aim of the study was to evaluate effects of anodal transabdominal tsDCS in prone lying on jumping height in less experienced (LEJ) and experienced (EJ) jumpers. Methods: Participants from LEJ (physical education students, 13 men and 10 women) and EJ (volleyball players, 13 men and 10 women) were subjected to a single 15-min session of anodal transabdominal tsDCS. Maximum vertical jumping height was measured during two sets of maximum squat jumps (SJs) and counter movement jumps (CMJs) performed in randomized order immediately, 30- and 60-min post stimulation. One set was composed of 3 jumps. There was 3-min break between the sets and 1 min rest between the jumps. Results: Two-way analysis of variance did not show the effect of interaction between the stimulation and time on jumping height during SJ (F _2,44 = 1.629; p = 0.208) and CMJ (F _2,44 = 1.304; p = 0.282) in EJ, as well as during SJ (F _2,44 = 1.346; p = 0.271) and CMJ (F _2,44 = 0.228; p = 0.747) in LEJ. Conclusion: TsDCS does not improve jump height in either squat or countermovement jumps in recreationally active and professional volleyball players. The results question the use of single session of transabdominal tsDCS in recreational or sports training to improve jumping performance.

This study investigated how the judgment of proximal joint position can be affected by touch alone, focused attention on the distal body part, or touch spatial localization. Participants completed a two-arm elbow joint position-matching task, in which they indicated the location of one forearm by the placement of the other. In four test conditions, matching was performed during (1) detection of touch (tactile stimulation of index finger pads), (2) spatial localization of fingers (attention focused on the position of index finger pads), (3) spatial localization of touch on fingers (attention focused on tactile stimulation of index finger pads), and (4) detection of touch but localization of fingers (tactile stimulation of index finger pads, but attention focusing on the spatial position of the pads). In the first experiment (n = 23), the sensitivity of muscle spindle receptors in both reference and indicator arms was reduced and equalized by both-slack conditioning. In the second experiment (n = 20), the illusion of excessive elbow flexion in the reference arm and excessive extension in the indicator arm was generated through extension-flexion conditioning. In the first experiment, the accuracy and precision of matching were unaffected in any test condition. In the second experiment, participants made amplified undershooting errors under attention-focused conditions. In conclusion, focused attention on the location of a distal body part and touch affects both the spatial localization of the limb and tactile remapping only when the perceived forearm position is misinterpreted due to imbalanced proprioceptive input from antagonistic arm muscles.

The aim of the present study was to determine if anodal transcutaneous spinal direct current stimulation (tsDCS) affects corticospinal excitability (CSE) and voluntary activation (VA) of the quadriceps femoris muscle (QM). This was a double‐blind, randomized study in which spine‐shoulder anodal tsDCS (active electrode centered over T11–12, 2.5 mA, 20 min) was applied in a seated position. Transcranial magnetic stimulation (TMS) was used to measure motor evoked potentials (MEP) and construct stimulus–response curves in healthy participants (eight females and five males, Experiment 1). VA was measured via the interpolated twitch technique, whereby muscle twitches were evoked using electrical femoral nerve stimulation and TMS (seven females and six males, Experiment 2). Measurements were carried out before, directly, and 30 min after sham and anodal tsDCS (with ≥4 days between sessions). There was no interaction between stimulation × time on stimulus–response curve expressed by slope, stimulus intensity corresponding to 50% of the maximal MEP, and peak‐to‐peak amplitude of the maximal MEP. Maximal voluntary isometric contraction (MVIC) torque did not change and VA was not affected regardless of the QM torque level (25, 50, or 100% of MVIC). A single, twenty‐minute session of spine‐shoulder anodal tsDCS did not increase CSE and VA of QM during submaximal and maximal contraction. This suggests that neither excitability to a known input nor responsiveness of motoneurons to submaximal and maximal cortical drive were affected by anodal tsDCS.

Introduction: It is commonly considered that myotonometry is a non-invasive method capable of quantifying linear elastic and viscoelastic properties of the myofascial tissue through the application of a weak mechanical impulse to the surface of the skin. However, before the impulse can reach the myofascial tissue, it must cross more superficial tissues such as the skin and subcutaneous tissue (ST). All these superficial tissues have different distributions and organizations of structural components. Therefore, the study aimed to examine the potential relationships between the mechanical and morphometric properties of various superficial soft tissues surrounding the lumbar multifidus muscle (LM).Methods: Myotonometric measurements of dynamic stiffness, logarithmic decrement, and creep, and ultrasonographic measurements of thickness and echogenicity of cutaneous, subcutaneous, perimuscular tissue, and LM were obtained from 50 healthy individuals in the resting prone position and during contralateral arm lift.Results: The most important findings were that in both the relaxed and contracted LM state, the dynamic stiffness strongly negatively (r = −0.69; p < 0.001 in relaxation, r = −0.83; p < 0.001 in contraction) and creep strongly positively (r = 0.79; p < 0.001 in relaxation, r = 0.85; p < 0.001 in contraction) correlated with the thicknesses of the ST. Similar but weaker correlations were noticed between both these measures and the perimuscular tissue thickness. Elasticity was uncorrelated to the thicknesses of the tissues. With LM contraction (change from the relaxed to contracted state), the relative increase in dynamic stiffness was correlated with the relative decrease in dermis (r = −0.51; p < 0.001) and ST (r = −0.47; p = 0.001) thickness, and with the relative increase in LM (r = 0.36; p = 0.010) thickness. Moreover, the relative decrease (thinning) in the ST thickness was correlated with the relative increase in logarithmic decrement (i.e., decrease in soft tissue elasticity, r = −0.37, p = 0.011). The mechanical properties of the soft tissues were not related to their echogenicity.Discussion: In conclusion, the thicker the subcutaneous and perimuscular layers, the lesser the stiffness and the greater the time-dependent deformation to the external force of the tissues surrounding the LM during its relaxation and isometric contraction. Moreover, the greater the thinning of the ST and the thickening of the LM during its contraction, the higher the increase in lumbosacral tissue stiffness and the decrease in elasticity. Therefore, one should consider the thickness of the ST before planning or analyzing the outcomes of myotonometric or other external biomechanical measurements to avoid drawing the wrong conclusions about the mechanical properties of the myofascial tissue.

Studies suggest that carnosine (beta-alanyl-L-histidine) is effective in treating neuromuscular diseases associated with aging, but there is still a need to clarify its role in motor units (MUs) function during aging. In this study, 40 male Wistar rats aged 15 months were randomly assigned to a control or to two experimental groups in which 0.1% carnosine supplementation was performed for 10 or 34 weeks. After 34 weeks, we examined fast fatigable (FF), fast fatigue-resistant (FR) and slow (S) MUs’ force properties and fatigability, as well as antioxidant potential, advanced glycation end products, activity of enzymes, and histidyl dipeptides content in the medial gastrocnemius muscle. Short- and long-term carnosine supplementation maintained the force of FF MUs at a higher level during its rapid decline seen from the initial 10 to 70 s of the fatigue test. In FF, especially long-term, and in FR MUs, especially short-term, carnosine supplementation resulted in less rapid force decline during the initial 70 s of the second fatigue protocol. Carnosine supplementation did not change muscle antioxidant potential and mortality rate (~35% in all groups), nor muscle mass with aging. Moreover, instead of the expected increase, a decrease in histidyl dipeptides by ~30% in the red portion of medial gastrocnemius muscle after long-term supplementation was found. After chronic carnosine supplementation, the specific changes in fatigue resistance were observed in FF and FR units, but not in S MU types that were not accompanied by an improvement of antioxidant potential and activity of glycolytic or oxidative enzymes in aged rats. These observations indicate that carnosine supplementation during aging may generate different physiological adaptations which should be considered as an important factor when planning treatment strategies.

Transcutaneous spinal direct current stimulation (tsDCS) increases corticospinal and spinal reflex excitability, and may be a new tool for increasing muscle explosive performance in sports training. The aim of the study was to evaluate whether tsDCS can enhance jumping ability in trained humans practicing volleyball. Twenty eight participants completed the study, including 21 men and 7 women. We investigated the effects of a single 15-minute session of sham, anodal, and cathodal tsDCS over spine and shoulder on repeated counter movement jump (CMJ) and squat jump (SJ) performance at 0, 30 and 60 min post-stimulation. The order of SJs and CMJs sets in each session was randomized. Each SJ and CMJ set consisted of 3 jumps. The break between each attempt was 1 min and the interval between the sets was 3 min. Two-way repeated measures ANOVA did not show effect of time, nor stimulation method, nor stimulation method × time interactions on SJ (time: F_(1.8,_142.1) = 1.054; p = 0.346, stimulation: F₍₂,₇₈₎ = 0.019; p = 0.981, stimulation × time: F_(3.6,_142.1) = 0.725; p = 0.564) or CMJ (time: F_(1.8,_140.9) = 2.092; p = 0.132, stimulation: F₍₂,₇₈₎ = 0.005; p = 0.995, stimulation × time: F_(3.6,_140.9) = 0.517; p = 0.705) performance. Single session of tsDCS over spine and shoulder does not increase jumping height in well-trained volleyball players. This is an important finding for coaches and strength conditioning professionals for understanding the practical utility of tsDCS for enhancing muscular explosiveness.

Context:Kinesio taping® (KT) is a therapeutic modality frequently used in the clinical practice for the treatment of various musculoskeletal disorders. It is often applied in patients with chronic low back pain (CLBP) to decrease pain and improve functional capacity. However, it is not known, whether thoracolumbar fascia Kinesio Taping® (KT) technique can decrease back pain, restore normal activity of paraspinal muscles and improve functional capacity in patients with lumbar disc herniation (LDH).Objective:To evaluate the impact of 7-day new KT stabilizing application on lumbar paraspinal muscles function, pain perception and disability in patients with LDH.Design:A randomized controlled trial.Setting:Human Performance Laboratory.Patients38 patients with LDH were randomized into KT (n=19) and placebo taping (PT, n=19) groups.Interventions:Both groups received the same "x" type application running over the back along fibres of superficial lamina of posterior layer of thoracolumbar fascia.Main Outcome Measu...

This study determined relationships between age, BMI and cranio-vertebral angle (CVA) (independent variables) and stiffness and elasticity of sternocleidomasteoid [SCM] and upper trapezius [UT] (dependent variables) muscles in sitting posture in 95 women across adult life. Moreover, a stepwise regression was performed to determine to what extent the dependent variables are explained by age, BMI and CVA. Age was moderately correlated with BMI (r = 0.41), and both age and BMI were moderately negatively correlated with CVA (r = −0.54 and −0.55, respectively). High (r = 0.73) and moderate (r = 0.53) linear relationships were present between age and logarithmic decrement (inversely related to elasticity) and stiffness of SCM muscle, respectively. Low (r = 0.36) and moderate (r = 0.47) relationships were present between age and logarithmic decrement and stiffness of UT muscle, respectively. Age accounted for 53% variance in elasticity and 28.5% variance in stiffness of SCM, and for 13% variance in elasticity and 22% variance in stiffness of UT muscle. Introduction of BMI but not CVA to the model explained the variance of these parameters by additional 0–8%. Among the studied factors age is the major correlate of stiffness and elasticity of neck muscles across the adult life.

The objective of the study was to assess the influence of forward head posture on the mechanical parameters and pressure pain threshold of superficial neck muscles in clinically nonsymptomatic individuals with sedentary jobs. Twenty-five office workers with forward head posture and 25 office workers with normal head posture were matched for sex, age, body mass index, and the nature and duration of their work and were compared at a single point. The study participants were divided into study groups on the basis of photometric craniovertebral angle measurements. The upper trapezius, sternocleidomastoid, and splenius capitis mechanical properties were assessed in the sitting position. Primary outcome measures were muscle stiffness (N/m), muscle tone (Hz), and muscle elasticity. The secondary variable was perceived pain threshold. No significant differences between the groups were found for biomechanical properties and perceived pain threshold in the studied muscles. Forward head posture has no impact on muscle stiffness, tone, and elasticity, nor does it increase the pressure sensitivity of superficial neck muscles in healthy, mildly symptomatic office workers. It is most likely that not incorrect posture of the cervical spine, but probably other factors combined with forward head posture, like comorbid acute and chronic cervical pain and musculoskeletal disorders or prolonged sitting, contribute to changes in active myofascial tone and tensegrity as well as increased pressure sensitivity of neck muscles.