Elbow Joint Position and Force Senses in Young and Adult Untrained People and Gymnasts.

Joint position (JPS) and force senses (FS) are the proprioception modalities. While the development of JPS was investigated both in children/adult and athlete/untrained conditions, there is a lack of insight into the development of FS. Overall, 28 gymnasts and 25 untrained controls underwent proprioception testing. They were divided into two groups: 9 to 11-year-old boys (13 gymnasts and 10 non-athletes) and 18 to 25-year-old adults (15 gymnasts and 15 non-athletes). The testing was performed at an isokinetic dynamometer and included elbow JPS and FS (20% and 50% maximal voluntary contraction) tasks. Children had two times higher error in JPS (p < 0.01) and 50% higher errors in FS of both flexor (p < 0.001) and extensor muscles (p < 0.05) in comparison with adults. Only in the 50% maximal voluntary contraction task, gymnasts showed 33% lower error than the controls (p < 0.01). Untrained boys presented 54%, 132%, and 169% higher error for elbow flexor performance than young gymnasts, untrained adults, and adult gymnasts, respectively (p < 0.01). The 9 to 11-year-old participants were characterized by a lower precision of JPS and FS performance in comparison with adults. Gymnastic training can possibly accelerate the development of FS when higher loads are considered.

Central Commands to the Elbow and Shoulder Muscles During Circular Planar Movements of Hand With Simultaneous Generation of Tangential Forces.

This study examines some of the non-linear effects of signal transduction in the human motor system, with particular emphasis on muscle hysteresis. The movement tests were analyzed in a group of eight subjects, which were asked to develop tangential force using visual biofeedback while performing slow, externally imposed, circular movements of right hand holding a moving handle operated by a computerized mechatronic system. The positional changes in the averaged EMGs of the elbow and shoulder muscles were compared for all combinations of direction of movement and generated force. Additionally, for one of the subjects, there was carried out MRI identification and 3D printing of the bones of the forelimb, shoulder, scapula and collarbone, which made it possible to reconstruct for him the length and force traces of all the muscles under study. The averaged EMG traces in muscles of both joints show their close correspondence to the related force traces, however, the co-activation patterns of activity in agonists and antagonists were also often encountered. The EMG waves related to the respective force waves were strongly dependent on the predominant direction of the muscle length changes within the correspondent force wave locations: the EMG intensities were higher for the shortening muscle movements (concentric contractions) and lower during muscle lengthening (eccentric contractions). The data obtained allows to suggest that for two-joint movements of the forelimbs, it is sufficient to consider the force and activation synergies (patterns of simultaneous activity in different muscles), ignoring at the first stage the effects associated with kinematic synergy. On the other hand, the data obtained indicate that the movement kinematics has a strong modulating effect on the activation synergy, dividing it into concentric and eccentric subtypes, in accordance with the known non-linear features of the muscle dynamics. It has been shown that the concentric and eccentric differences in the responses of the shoulder muscles are more clearly distinguishable than those in the elbow muscles. The shoulder muscles also have a more pronounced symmetry of the averaged EMG responses with respect to the ascending and descending phases of force waves, while demonstrating a lower degree of antagonist cocontraction. The data obtained suggest that the central commands in two-joint movements are determined mainly by the interdependence of force and activation synergies including both intra- and inter-joint components, while kinematic synergy can be interpreted as a potent modulator of activation synergy.

Different Changes in Adipokines, Lipid Profile, and TNF-Alpha Levels between 10 and 20 Whole Body Cryostimulation Sessions in Individuals with I and II Degrees of Obesity.

Obesity is associated with chronic inflammation. While cold therapy influences the pro/antioxidative status of an individual, by affecting adipokine levels and the lipid profile, the effect of body mass index (BMI) on the response to cold exposure is unclear. We analyzed the link between BMI and the differences in effects of whole-body stimulation, depending on the number of treatments, on specific physiological parameters in men. Twenty-seven non-active men were divided into three groups: N (n = 9, BMI < 24.9), IOb (n = 9, BMI 30.0-34.9), and IIOb (BMI ≥ 35.0). The subjects participated in 20 3-min cryochamber sessions (-120 °C), 1/day, 5 days/week. Body composition was analyzed before and after treatment. Blood adiponectin (ADP), leptin (LEP), and tumor necrosis factor alpha (TNF-alpha) levels, and the lipid profile were analyzed three times: at baseline and up to 2 h after 10 and 20 sessions. The 20 treatments caused significant changes in body composition. Between 10 and 20 whole-body cryostimulation (WBC) sessions, a significant decreased was observed in the LEP and TNF-alpha levels. No significant changes in the lipid profile were noted. However, a positive tendency to regain the metabolic balance in adipose tissue was apparent in the IOb group in the tested period (decreased TG levels, increased HDL levels or the HDL/LDL ratio, and significantly decreased visceral adiposity index levels). Collectively, for people with obesity increasing the number of treatments above the standard 10 should be recommended.

Influence of Classical Massage on Biochemical Markers of Oxidative Stress in Humans: Pilot Study.

Classical massage is one of the most popular forms of conservative treatment in various diseases. Despite the wide scope of research, the mechanisms of massage are not fully known and understood. Apart from the well-described effects on individual body systems, there are few scientific reports on the effects of massage on the human body at the subcellular level. The study was designed to assess changes in oxidative stress parameters in healthy volunteers after a single session of classical massage. 29 healthy volunteers aged 22.24 ± 3.64 participated in the study. Before and 30 minutes after the massage procedures, blood samples were taken by experienced personnel. Biochemical markers of oxidative homeostasis were assessed with highly specific methods for each parameter: oxidase ceruloplasmin, glutathione, malondialdehyde, glutathione peroxidase, glutathione S-transferase, and superoxide dismutase. The study demonstrates that massage therapy caused statistically significant decrease in the concentration of glutathione peroxidase (red blood cells) and increase in the level of glutathione peroxidase (plasma), superoxide dismutase, and malondialdehyde. In contrast, statistically significant changes in the hematocrit, glutathione, NO2-/NO3-, and oxidase ceruloplasmin were not observed. The results show that complex influence of classical massage therapy on human organism may be reflected in parameters of the oxidative stress. To understand this mechanism clearly, further research is needed.

The Neuromuscular Characteristics of Gymnasts' Jumps and Landings at Particular Stages of Sports Training.

Safe and proper landings are crucial elements of gymnastics events. Long-term training leads to specific neuromuscular adaptations which are yet to be explored in terms of gymnastic landings. The aim of the study was to assess differences in landings' neuromuscular characteristics between gymnasts at three subsequent gymnastic training stages and age-matched non-athletes. Forty-six gymnasts (G) and 58 controls (C) performed countermovement jumps on a force plate with simultaneous surface electromyography (SEMG) of lower body muscles, measured during the pre-(100 ms) and post-landing phase (0-100 and 0-200 ms). Three age groups participated in the study: 8-10 (G1, C1), 12-14 (G2, C2), 18-25 (G3, C3) years. Analysis included the normalized root mean square (NRMS) SEMG signal and ground reaction forces (GRFs). Gymnasts achieved 13% higher values (p = 0.04) of relative peak GRFs in comparison with controls. It was especially seen in 8-10-year-olds: G1 presented 33% higher (p = 0.03) results than C1 and G2. In SEMG analysis, gymnasts showed overall lower NRMS values in comparison with the controls. In the pre-landing phase, the NRMS in the rectus femoris was from 1.6 up to 3.4 times higher for C1 (p = 0.02) than for C2, G2, C3, and G3. Gymnasts across subsequent training stages exhibit different patterns of neuromuscular coordination during landings. The highest GRF observed in the youngest gymnasts may be a potential risk factor of injuries. Therefore, further injury-focused investigation is recommended to monitor landing strategies among gymnasts of different stages with particular emphasis on the beginners.

Effect of six weeks 1000 mg/day vitamin C supplementation and healthy training in elderly women on genes expression associated with the immune response - a randomized controlled trial.

BACKGROUND: In this study, we investigated the effects of supplementation and exercise on the expression of genes associated with inflammation like CCL2, CRP, IL1, IL6, IL10 mRNA in elderly women. METHODS: Twenty four participants divided randomly into two groups were subjected to 6 weeks of the same health training program (three times per week). SUP group (supplemented, n = 12, mean age 72.8 ± 5.26 years and mean body mass 68.1 ± 8.3 kg) received 1000 mg of Vitamin C/day during the training period, while CON group (control, n = 12, mean age 72.4 ± 5.5 years and body mass 67.7 ± 7.5 kg) received placebo. RESULTS: No significant changes in IL-1, IL-6, IL-10 and CRP mRNA were observed within and between groups. However, there was a clear tendency of a decrease in IL-6 (two-way ANOVA, significant between investigated time points) and an increase in IL-10 mRNA noted in the supplemented group. A significant decrease in CCL2 mRNA was observed only in the CON group (from 2^0.2 to 2^0.1, p = 0.01). CONCLUSIONS: It can be concluded, that 6 weeks of supplementation and exercise was too short to obtain significant changes in gene expression in leukocytes, but supplementation of 1000 mg vitamin C positively affected IL-6 and IL-10 expression - which are key changes in the adaptation to training. However, changes in body mass, IL1 and CCL2 were positive in CON group. It is possible that Vitamin C during 6 weeks of supplementation could have different effects on the expression of individual genes involved in the immune response. TRIAL REGISTRATION: Retrospectively registered.

Comparison of the Physical Demands of Friendly Matches and Different Types On-Field Integrated Training Sessions in Professional Soccer Players.

The aim of this study was to investigate the relationships among physical demands of two friendly matches (FMs) and three task training sessions (TS1,2,3) combining in a different way: a Small-Sided Game (SSG), Mini-Goals (MG), a ball Circuit Training (CT) and a Large-Sided Game (LSG): SSG+MG+LSG (TS1), SSG+CT+LSG (TS2) and MG+CT+LSG (TS3). The TS and match demands in running intensities were monitored in fourteen professional soccer players (age = 23.2 ± 2.7 years, height = 178 ± 6 cm, body mass = 73.2 ± 6.9 kg, mean and SD, respectively) using 10-Hz global positioning system devices, and players' perception of exertion was recorded after each session or match using a visual analogue scale. A one-way repeated measures ANOVA with a Bonferroni correction coupled with magnitude-based inferences were used. A principal component (PC) analysis was conducted on all variables to account for covariance. Three PCs were retained, explaining 76% of the variance: Component 1 explained 46.9% with the associated variables: Total Distance (TD) and distance covered in ranges of speed from >2.2 to <5 m/s, Player Load and Work Rest Ratio; component 2 explained 19.7% and was composed of TD at > 5 m/s and maximal running speed (MRS); and component 3 explained 9.5% and was represented by TD < 2.2 m/s, decelerations and accelerations. The ANOVA results showed significant differences (p < 0.05) among TS vs. FM in TD3, TD4, TD5, and TD > 5, TD, deceleration rate, acceleration rate, maximal running speed, exertion index, work rest ratio, and self-reported exertion. Therefore, the training routines did not replicate the main set of high intensity efforts experienced in competitive conditions. Additionally, PC analysis could be applied in order to select the most representative training and competitive conditions.

The effect of whole-body cryostimulation on body composition and leukocyte expression of HSPA1A, HSPB1, and CRP in obese men.

In recent years, the prevalence of obesity has increased dramatically and has become a 21st century epidemic. Obesity is associated with the development of many diseases, and therefore treatments that can reduce body mass are actively sought. The aim of this study was to examine the effect of 20 cryostimulation sessions on body composition in obese/high body mass (HBM, n = 12) males and normal body mass (NBM, n = 9) controls. The HBM group had a mean age = 29.08 ± 4.19 years, body fat percentage = 32.08 ± 6.16%, body mass index = 36.23 ± 8.13 kg/m2) and NBM group had a mean age = 22.00 ± 2.45 years, body fat percentage = 12.14 ± 4.93%, body mass index = 23.58 ± 2.00 kg/m2. Kilocalorie intake was similar for both groups. All participants received 20 sessions of systemic cryostimulation at -120°C for 2-3 min in a cryochamber. Blood samples were collected before the first session, 1 h after the 10th session, and 1 h after the 20th cryostimulation session. C-reactive protein (CRP) plasma concentrations, and expression of the heat shock protein genes (HSPA1A, HSPB1) and CRP mRNA in leukocytes were evaluated after 10 and 20 cryostimulation sessions. In both groups, 20 sessions were associated with a significant decrease in body mass, fat mass and the percentage of body fat. CRP concentrations were significantly higher in obese people before the first session and after 10 treatments, but not at the end of study. Expression of HSPA1A and HSPB1 mRNA gradually decreased with the number of cryostimulation sessions. A significant difference in HSPA1A expression was found after 20 sessions (NBM > HBM) and for HSPB1 at baseline and after 20 sessions (HBM > NBM). Our results show that cryostimulation influences body composition and that cryostimulation-induced HSP genes expression depends on the number of cryosessions and baseline body mass, and is differentially altered in HBM individuals. Further research on the interaction between body mass and cold adaptation is warranted.

Hysteresis and Synergy of the Central Commands to Muscles Participating in Parafrontal Upper Limb Movements.

The averaged electromyograms (EMGs) were registered from the arm muscles of ten subjects in movements of the right hand performed under visual guidance on the horizontal plane along linear trajectories going parallel to the frontal plane at various distances from the trunk. The tests consisted of the steady movements (speed 4 cm/s) between two points symmetrical about the shoulder axis; the hand moved firstly from left to right, then in the opposite direction. The tests repeated ten times for each of two equal loads (10.2 N) applied to the hand along movement trajectory in the right- (F r ) or leftward (F l ) directions. The elbow and shoulder flexors reacted predominantly on F r loads; the extensors were mostly activated by F l loads. Positional changes of the averaged EMGs in both flexor and extensor muscles belonging to different joints demonstrated hysteresis properties; the respective hysteresis loops had counterclockwise direction in flexors and clockwise in extensors. The muscles predominantly opposing the loading forces of a given direction participate in a cocontraction mode as antagonists when the direction of load is changed; in this case, together with a decrease in the amplitude of the hysteresis loops, their direction is also reversed. The multiplication index of synergy (MIS), which is based on multiplication of the respective normalized averaged EMG records, has been proposed to evaluate quantitatively changes in the synergy effects between various muscle groups. For distal shifts of the movement traces, the synergy effects are shown to be changed in different directions, increasing in flexors and decreasing in extensors. The obtained results demonstrate that the muscle hysteresis leads to strong modification of the central commands during movements.

Changes in the Muscle Activity of Gymnasts During a Handstand on Various Apparatus.

Kochanowicz, A, Niespodzinski, B, Mieszkowski, J, Marina, M, Kochanowicz, K, and Zasada, M. Changes in the muscle activity of gymnasts during a handstand on various apparatus. J Strength Cond Res 33(6): 1609-1618, 2019-Gymnasts perform handstands on various apparatus, both in stable and unstable conditions. Such performances require specific muscle activation, which should differ depending on the condition and expertise of the gymnast. Therefore, the aim of the study was to evaluate (a) the difference in electromyography (EMG) between handstands performed on 3 apparatus (floor, rings, and parallel bars); and (b) the difference between young and well-trained adult gymnasts. Ten adult (25 ± 3.94 years) and 15 young (13.9 ± 0.7 years) gymnasts participated in the study. We investigated EMG amplitude in 13 muscles normalized by arbitrary angle maximal isometric voluntary contraction (normalized root mean square [NRMS]). In comparison with the handstand on the floor (61 ± 28%), the wrist flexor muscles of gymnasts exhibited a decreased NRMS on the parallel bars (44 ± 25%; p = 0.017), and rings (46 ± 32%; p = 0.029), whereas no changes were observed in the triceps brachii. The rest of the investigated muscles showed a higher NRMS in rings. Differences between young and adult gymnasts were seen in the triceps brachii and anterior deltoid muscles, where more experienced gymnasts showed 19.1% (p = 0.014) and 17.6% (p = 0.048) lower NRMS, respectively. The different gymnastic apparatus led to specific muscle activation. This activation predominantly depended on hand support conditions, which alternated the primary wrist strategy of the handstand balance control, and in consequence, the activation of other muscles controlling balance. Training focused on the development of motor control and strength of the anterior deltoid, pectoralis major, latissimus dorsi, biceps brachii, and trapezius descendens muscles to improve handstand performance.

Motion analysis of elite Polish soccer goalkeepers throughout a season.

The study aims were to determine the distance covered by goalkeepers during matches in the context of game duration and result, to identify the area of their most frequent activity, and to assess goalkeepers' involvement in games finished with a win, draw, or loss. The investigation was based on two innovative tools: the goalkeeper's activity index (GAI) and an analysis of 5-min periods. A video tracking system was used to monitor 17 goalkeepers from Polish National League teams during 15 matches. The GAI was applied to assess their involvement in the game. Elite goalkeepers covered 72.7%, 25.8%, and 2.5% of the distance during the game by walking/jogging, running, and sprinting, respectively. The distances covered in lost, won, and drawn matches turned out similar (mean ± SD: 4800 ± 906 m, 4696 ± 1033 m, and 4660 ± 754 m, respectively). There were no significant differences between the distances covered in the first and second halves. The area of most frequent activity was the middle sector of the penalty area between the goal and penalty area lines. ANOVA results showed that in drawn matches, goalkeepers' activity significantly differed in mean values of the GAI in comparison with that in won and lost games (p = 0.034, p = 0.039, respectively). It was noted that goalkeepers tended to intervene more often in games where their team was winning rather than in those with a losing result. Their direct involvement in defending the goal was the lowest in drawn games.