Jonas Poderys

Effect of Lower Body Compression Garments on Hemodynamics in Response to Running Session

Purpose. Compression garments are often worn during exercise and allegedly have ergogenic and/or physiological effects. In this study, we compared hemodynamics and running performance while wearing compression and loose-fit breeches. We hypothesized that in neutral-warm environment compression breeches impair performance by diminishing body cooling via evaporative sweat loss and redistributing blood from active musculature to skin leading to a larger rise in body temperature and prolonging recovery of hemodynamics after exercise. Methods. Changes in hemodynamics (leg blood flow, heart rate, and blood pressure during orthoclinostatic test), calf muscle tissue oxygenation, and skin and core temperatures were measured in response to 30 min running (simulation of aerobic training session) followed by maximal 400 m sprint (evaluation of running performance) in recreationally active females (25.1 ± 4.2 yrs; 63.0 ± 8.6 kg) wearing compression or loose-fit breeches in randomized fashion. Results. Wearing compression breeches resulted in larger skin temperature rise under the garment during exercise and recovery (by about 1°C, P < 0.05; statistical power > 85%), while core temperature dynamics and other measured parameters including circulation, running performance, and sensations were similar compared to wearing loose-fit breeches (P > 0.05). Conclusion. Compared with loose-fit breeches, compression breeches have neither positive nor negative physiological and performance effects for females running in thermoneutral environment.

Cardiovascular response to bouts of exercise with blood flow restriction

[Purpose] Occlusion training with low-intensity resistance exercises and blood flow restriction increases muscle cross-sectional area and strength. This form of training is used in rehabilitation; therefore, the aim of this study was to examine the effect of one occlusion training session on the cardiovascular response to bouts of exercise. [Subjects and Methods] Two groups took part: a control group without blood flow restriction and an experimental group with blood flow restriction. A single training session was used with the exercise intensity set at 40% of the one repetition maximum. Maximum voluntary contraction, arterial blood pressure, and electrocardiogram measurements were performed. [Results] Heart rate was slightly higher in the control group. The performed training had no effect on diastolic blood pressure in either group, however, a tendency for a small systolic blood pressure increase was observed during the session in the experimental group. JT interval changes did not reveal significant differences between groups. There were no significant changes in ST-segment depression during the exercise or at rest. A lower tendency for JT/RR increases was observed during the repeated exercise tasks with partial blood flow restriction. [Conclusion] Low intensity exercises carried out with a partial blood flow restriction do not result in significant overload of cardiac function.

Cardiovascular Response to Breath-Holding Explained by Changes of theIndices and their Dynamic Interactions

Background: Endogenous triggers such as voluntary breath-holding induce various cardiovascular responses typically including modification of blood CO2. During dynamic exercise these responses may have a negative impact on performance or may associate with cardiovascular risk subjects. Therefore, we hypothesized that voluntary breathing tests induce changes in cardiovascular (CV) oxygenation that lead to cardiovascular-functional changes, measured by a complex of integrated cardiovascular parameters and their interactions. So the aim of the study was to determine the impact of the voluntary breath-holding on changes and interplay of cardiac and peripheral parameters. Method: 18 girls (average age: 23.4 ± 1.3 years) performed 2 voluntary breath-holdings to failure, with a 5 min rest. Cardiac functional parameters were recorded using the electrocardiogram (ECG) analysis system “Kaunas-load”. The blood flow in the calf was determined by venous occlusion plethysmography. Near-infrared spectroscopy (NIRS) was used for non-invasive monitoring of oxygen saturation in tissues (StO2). Results: Throughout the first breath-holding, heart rate (HR) increased from 89.5 ± 3.9 bpm to 107.6 ± 4.2 bpm (P<0.05). The ECG JT interval decreased at the onset of breath-holdings, the intervals ratio (JT/RR) increased (P<0.05), and the ST-segment depression was not altered significantly. Arterial blood flow (ABF) was reduced from 3.5 ± 0.47 mL/100 mL/min to 1.64 ± 0.38 mL/100 mL/min (P<0.05) at the end of the first breath-holding. The StO2 of the calf muscles decreased during both breath-holdings. Within 60 s of recovery time, StO2 exceeded baseline 9.5% (P<0.05). Conclusion: Breath-holding impact changes in the systemic (central) circulation and caused significant peripheral changes, i.e., decrease in arterial blood flow and oxygen saturation. The most essential alteration occurred between the HR and arterial blood pressure (ABP) parameters. The strongest interaction observed between HR and ABP, and in calf muscles - between ABF and StO2.

Restoration of the Work Capacity of the Skeletal Muscle With Electrical Myostimulation

Abstract Kibiša, R, Grūnovas, A, Poderys, J, and Grūnovienė, D. Restoration of the work capacity of the skeletal muscle with electrical myostimulation. J Strength Cond Res 27(2): 449–457, 2013—The aim of this study was to evaluate the effects of applying mild electrical myostimulation (EMS) or passive rest (PR) on restoring the work capacity (WC) of the skeletal muscles in athletes. Nineteen long-distance runners participated in the study. They were divided into 2 groups according to the principle of rotation: a PR (control) and an EMS (experimental) group. They were examined before training and 10 minutes, 4 hours, and 18 hours after training. Muscle motor function was measured as the maximal voluntary contraction (MVC) and WC. The intensity of the arterial blood flow and the venous reserve volume with venous occlusion plethysmography, and the stroke volume, cardiac output, and heart rate with tetrapolar rheography were determined. The application of EMS significantly increased the MVC and WC of the calf muscles (p ⩽ 0.05) compared with the corresponding parameters recorded after PR. The venous reserve volumes after PR (0.61 ± 0.07 ml per 100 ml) and EMS (0.91 ± 0.11 ml per 100 ml) differed significantly (p ⩽ 0.05). Mild EMS is an effective local method of restoring the WC of the muscles. It is greatly superior to PR, which is the traditional way of recovering from exercise. The increased WC of the muscle was mediated by improved blood flow in the stimulated muscles and an increased venous blood pump. The systemic circulation, evaluated with cardiac indicators such as stroke volume, cardiac output, and heart rate, played no significant role in the effect.

Effect Of Electrical Myostimulation On The Function Of Lower Leg Muscles.

Electrical myostimulation (EMS) method is applied to improve skeletal muscle function. The aim of this study was to evaluate the efficacy of EMS applied to the sole and calf muscles on their strength and on maximal sprint performance. Each of 10 training sessions involved 10 seconds of stimulation and 50 seconds of rest for a total of 10 minutes. After the 10 training sessions, the maximal voluntary contraction (MVC) of right calf muscles increased by 6.0% from 830.0 ± 47.0 N to 878.0 ± 45.3 N (p ≤ 0.05). When EMS was applied to trained athletes, their 10-m sprint performance improved by 2.1% (p ≤ 0.05). In the second part of the study, a 3-week training program with EMS was applied to athletes, which significantly improved their 10-m sprint performance from a standing start by 5.3% and from a running start by 4.7% (p ≤ 0.05). Thus, 10 EMS cycles up to the maximal tolerated intensity applied every other day improved the MVC of foot flexion muscles and 10-m sprint performance from both standing and running starts. Three weeks of EMS training did not affect the intensity of calf muscle blood flow and oxygen saturation at rest. The training program supplemented with 10 EMS sessions produced significantly greater effects on the 10-m sprint performance from both a standing and a running start.Electrical myostimulation (EMS) method is applied to improve skeletal muscle function. The aim of this study was to evaluate the efficacy of EMS applied to the sole and calf muscles on their strength and on maximal sprint performance. Each of 10 training sessions involved 10 s of stimulation and 50 s of rest for a total of 10 min. After the 10 training sessions, the maximal voluntary contraction (MVC) of right calf muscles increased by 6.0% from 830.0 ± 47.0 N to 878.0 ± 45.3 N (P < 0.05). When EMS was applied to trained athletes, their 10-m sprint performance improved by 2.1% (P < 0.05). In the second part of the study, a 3-week training program with EMS was applied to athletes, which significantly improved their 10-m sprint performance from a standing start by 5.3% and from a running start by 4.7% (P < 0.05). Thus, 10 EMS cycles up to the maximal tolerated intensity applied every other day improved the MVC of foot flexion muscles and 10-m sprint performance from both standing and running starts. Three weeks of EMS training did not affect the intensity of calf muscle blood flow and oxygen saturation at rest. The training programme supplemented with 10 EMS sessions produced significantly greater effects on the 10-m sprint performance from both a standing and a running start.

Cardiovascular changes during the performance by nonathletes of Bosco repeated jumps anaerobic test

OBJECTIVE The aim of this study was to find out the characteristics of cardiovascular changes when performing Bosco repeated jumps anaerobic test depending on the duration of jumping in a nonathletes cohort. MATERIALS AND METHODS Changes in arterial blood pressure indices and changes in 12-lead ECG indices were analyzed. The characteristics of recovery after workloads were assessed by evaluating the time of half period of recovery of registered indices and by the Lyapunov exponent. RESULTS The results have shown that the ratio of JT and RR intervals of ECG (JT/RR) can be useful for outlining to what extent a cardiovascular function was mobilized. The mobilization of cardiovascular function when performing a 30-s jump test changed up to 0.454±0.012 and when performing a Bosco test, up to the maximal values, i.e. 0.634±0.004. When performing jumps of maximal intensity, a maximal change of JT/RR occurrence was between 50 and 60s. The increasingly serious myocardial ischemic episodes were observed at the onset of the jumping task. The duration of 60-s of all-out jump test has made an influence on the stability of the recovery processes of cardiovascular indices, i.e. the nonexponential type of recovery was observed. CONCLUSIONS When performing Bosco 60-s repeated jumps in an anaerobic test, a maximal mobilization of the cardiovascular system occurs between 50 and 60s. The 30-s all-out test duration in jumping is enough to outline at what extent cardiovascular function was mobilized as well as to assess other functional characteristics during high intensity intensive exercising.

Trumpam sulaikomo kvėpavimo įtaka širdies ir kraujagyslių sistemai atliekant dozuoto fizinio krūvio mėginį

Kvėpavimas yra refleksinis, o kartu ir valingas veiksmas, todėl kvėpavimo intensyvumo pokyciai arba kvėpavimo sulaikymai gali turėti įtakos organizmo vegetacinėms funkcijoms ir jų pokyciams fizinių krūvių metu. Tyrimo tikslas. Nustatyti, ar nepakinta sirdies ir kraujagyslių sistemos (SKS) funkcinės būklės rodikliai, kai tiriamieji krūvio pradžioje nevalingai arba valingai trumpam sulaiko kvėpavimą. Metodika. Atlikti du tyrimai. Pirmojo tyrimo metu vertinta sveikų vyrų, pakviestų pirmą kartą atlikti fizinio krūvio mėginį, psichomotorinis tonusas ir isorinio kvėpavimo savybės. Tiriamieji atliko Rufjė fizinio krūvio mėginį (30 pritūpimų per 45 sek., pritūpiant iki 90° per kelio sąnarį). Krūvio metu ir pirmąsias dvi atsigavimo minutes buvo registruojama 12-kos standartinių elektrokardiogramos derivacijų ir matuojamas arterinis kraujo spaudimas. Viso tyrimo metu buvo registruojamos kvėpavimo bangos. Antrojo tyrimo metu buvo vertinta trumpo valingo kvėpavimo sulaikymo įtaka SKS funkcinių rodiklių pokyciams atliekant dozuoto fizinio krūvio mėginį. Rezultatai. Tyrimas parodė, kad padidėjusio psichomotorinio tonuso asmenys, atlikdami dozuoto fizinio krūvio mėginį, jo pradžioje dažniau nevalingai sulaiko kvėpavimą. Trumpas kvėpavimo sulaikymas dozuoto fizinio krūvio pradžioje pakeicia sirdies ir kraujagyslių sistemos funkcinius rodiklius: lėciau didėja sirdies susitraukimų dažnis, mažiau kinta elektrokardiogramos JT intervalas, sumažėja greitosios adaptacijos fiziniam krūviui greitis, turi tendenciją didėti arterinio kraujo spaudimo rodikliai ir reiksmingai sulėtėja rodiklių atsigavimas po krūvio. Isvada. Atliekant dozuoto fizinio krūvio mėginius, santykinai dažnai pasitaikantis nevalingas kvėpavimo sulaikymas pakeicia sirdies ir kraujagyslių sistemos funkcinius rodiklius fizinio krūvio ir atsigavimo metu dėl to funkcinė būklė gali būti įvertinta nevisiskai tiksliai.