Near-InfraRed Spectroscopy Provides a Reproducible Estimate of Muscle Aerobic Capacity, but Not Whole-Body Aerobic Power.

Near-infrared spectroscopy (NIRS) during repeated limb occlusions is a noninvasive tool for assessing muscle oxidative capacity. However, the method's reliability and validity remain under investigation. This study aimed to determine the reliability of the NIRS-derived mitochondrial power of the musculus vastus lateralis and its correlation with whole-body (cycling) aerobic power (V̇O2 peak). Eleven healthy active men (28 ± 10 y) twice (2 days apart) underwent repeated arterial occlusions to induce changes in muscle oxygen delivery after 15 s of electrical muscle stimulation. The muscle oxygen consumption (mV̇O2) recovery time and rate (k) constants were calculated from the NIRS O2Hb signal. We assessed the reliability (coefficient of variation and intraclass coefficient of correlation [ICC]) and equivalency (t-test) between visits. The results showed high reproducibility for the mV̇O2 recovery time constant (ICC = 0.859) and moderate reproducibility for the k value (ICC = 0.674), with no significant differences between visits (p > 0.05). NIRS-derived k did not correlate with the V̇O2 peak relative to body mass (r = 0.441, p = 0.17) or the absolute V̇O2 peak (r = 0.366, p = 0.26). In conclusion, NIRS provides a reproducible estimate of muscle mitochondrial power, which, however, was not correlated with whole-body aerobic capacity in the current study, suggesting that even if somewhat overlapping, not the same set of factors underpin these distinct indices of aerobic capacity at the different (peripheral and whole-body systemic) levels.

Riding a Mechanical Scooter from the Inconvenient Side Promotes Muscular Balance Development in Children.

Mechanical scooter riding is a popular physical activity among children, but little is known about the differences in muscle loading between the dominant and non-dominant sides during this activity. The objective of this study was to identify the muscle activation patterns in children's dominant and non-dominant legs as they rode scooters on the convenient and inconvenient sides. The study included nine healthy children aged 6-8. The participants rode 20 m on a mechanical scooter at a self-selected pace using both the convenient and inconvenient sides. Electromyography was used to measure the muscle activity in the dominant and non-dominant legs during the pushing and gliding phases. A 20 m sprint run was used as a control exercise to estimate the typical differences in muscle activation between the dominant and non-dominant legs. In the pushing phase, the symmetry index for five of the eight analyzed muscles exceeded 50% (p < 0.05); four of these muscles were more active in the pushing leg, and one was more active in the standing leg. In the gliding phase, four muscles were more active in the standing leg, and one was more active in the pushing leg (p < 0.05). Upon observing children who changed sides while riding a scooter, it was found that the pattern of muscle activation displayed a reverse trend that resembled the initial pattern. Our study indicated notable differences in muscle activity patterns between the dominant and non-dominant sides of individual leg muscles during children's scooter riding. These patterns were reversed when children switched sides on the scooter. These findings suggest that using both legs and switching sides while riding a scooter may be a viable strategy for promoting balanced muscular development.

The Relationships between Psychological Well-Being, Emotions and Coping in COVID-19 Environment: The Gender Aspect for Postgraduate Students.

BACKGROUND: Postgraduate students were exposed to the Coronavirus pandemic, and their study process changed from face-to-face to online. The purpose of this study was to analyze the impact of gender differences on emotions, coping strategies and psychological well-being (PWB) in the environment of the Coronavirus pandemic second wave (11 July 2020-30 June 2021). METHODS: Ryff scale, MEQ Multidimensional emotion questionnaire, and brief COPE scale. The participants' consisted of postgraduate students (74 female and 54 male). The study was conducted from 21 June 2022 to 28 June 2022. RESULTS: Postgraduate students rated their PWB levels insignificantly in terms of gender. However, the individual components of this construct were evaluated as being significantly different in terms of gender. Females were more likely to feel negative emotions and had a harder time regulating these emotions than males. Female students were less likely than males to use problem-focused and avoidant-focused coping strategies. CONCLUSIONS: Postgraduate females were more affected than males by the Coronavirus pandemic. Females' PWB was more concerned with emotions than males. Females were less likely than males to use problem-focused coping strategies.

The Role of Gender in Association between Emotional Intelligence and Self-Control among University Student-Athletes.

The purpose of this study was to reveal the peculiarities of undergraduate studies university student-athletes' emotional intelligence and self-control indicators, and the role of gender as a predictor in the association between emotional intelligence and self-control. The study included students regularly involved in training at least three times a week. The sample consisted of 1395 student athletes from Lithuanian universities, among them 59.2% female and 40.8% male. For measurement, the SSRI inventory and a self-control scale were used. All values of emotional intelligence indicators were significantly higher for males than females. Estimates of the components of the self-control construct varied. The score for the healthy habits component was significantly higher for women than for men, the self-discipline component did not differ significantly, and the other three components were higher for males. Estimates of the components of the self-control construct varied. Models for predicting the values of self-control components were proposed. Only one component of the emotional intelligence construct, optimism, was repeated in all forecasting models, as well as gender. Other components of emotional intelligence vary in models.

Effects of a Physical Education Program on Physical Activity and Emotional Well-Being among Primary School Children.

(1) Background: It has been identified that schools that adopt at least two hours a week of physical education and plan specific contents and activities can achieve development goals related to physical level, such as promoting health, well-being, and healthy lifestyles, on a personal level, including bodily awareness and confidence in physical skills, as well as a general sense of well-being, greater security and self-esteem, sense of responsibility, patience, courage, and mental balance. The purpose of this study was to establish the effect of physical education programs on the physical activity and emotional well-being of primary school children. (2) Methods: The experimental group comprised 45 girls and 44 boys aged 6-7 years (First Grade) and 48 girls and 46 boys aged 8-9 years (Second Grade), while the control group comprised 43 girls and 46 boys aged 6-7 years (First Grade) and 47 girls and 45 boys aged 8-9 years (Second Grade). All children attended the same school. The Children's Physical Activity Questionnaire was used, which is based on the Children's Leisure Activities Study Survey questionnaire, which includes activities specific to young children (e.g., "playing in a playhouse"). Emotional well-being status was explored by estimating three main dimensions: somatic anxiety, personality anxiety, and social anxiety. The Revised Children's Manifest Anxiety Scale (RCMAS) was used. (3) Results: When analysing the pre-test results of physical activity of the 6-7- and 8-9-year-old children, it turned out that both the First Grade (92.15 MET, min/week) and Second Grade (97.50 MET, min/week) participants in the experimental group were physically active during physical education lessons. When exploring the results of somatic anxiety in EG (4.95 ± 1.10 points), both before and after the experiment, we established that somatic anxiety in EG was 4.55 ± 1.00 points after the intervention program, demonstrating lower levels of depression, seclusion, somatic complaints, aggression, and delinquent behaviours (F = 4.785, p < 0.05, P = 0.540). (4) Conclusions: We established that the properly constructed and purposefully applied eight-month physical education program had positive effects on the physical activity and emotional well-being of primary school children (6-7 and 8-9 years) in three main dimensions: somatic anxiety, personality anxiety, and social anxiety. Our findings suggest that the eight-month physical education program intervention was effective at increasing levels of physical activity. Changes in these activities may require more intensive behavioural interventions with children or upstream interventions at the family and societal levels, as well as at the school environment level. These findings have relevance for researchers, policy makers, public health practitioners, and doctors who are involved in health promotion, policy making, and commissioning services.

Effect of different exercise programs on non-specific chronic low back pain and disability in people who perform sedentary work.

BACKGROUND: This study compared the short- and long-term effects of different exercise programs on lumbar muscle function, cross-sectional area of the multifidus muscle, functional disability and low back pain in people who perform sedentary work. METHODS: A total of 70 volunteer women with sedentary occupations suffering from low back pain were randomized to either the lumbar stabilization exercise program group or the lumbar muscle strengthening exercise program group. All subjects entered the 20-week exercise programs. The measurement of the cross-sectional area of the multifidus muscle was executed by using an ultrasound system, isokinetic peak torque was measured applying an isokinetic dynamometer. FINDINGS: The results indicated that the 20-week exercise programs reduced low back pain and functional disability. Positive effects for the cross-sectional area of the multifidus muscle, functional disability and low back pain lasted for 4 weeks after the application of lumbar muscle strengthening exercise program and for 12 weeks after the application of lumbar stabilization exercise program. The lumbar muscle strength increased and lasted for 8 weeks after both exercise programs. INTERPRETATION: The 20-week lumbar stabilization exercise and muscle strengthening exercise programs were efficacious in decreasing LBP and functional disability in people performing sedentary work, however the lumbar stabilization exercise program was more effective, and this effect lasted for 12 weeks after completion of the program.

Low frequency fatigue and changes in muscle fascicle length following eccentric exercise of the knee extensors.

NEW FINDING: What is the central question of this study? Does low frequency muscle fatigue indicate a failure of excitation-contraction coupling after eccentric exercise, or is it simply due to a change in muscle length? What is the main finding and its importance? The low to high frequency muscle fatigue ratio was relatively insensitive to changes in muscle length, and any changes in length following eccentric exercise were far too small to account for the high degree of low frequency fatigue. The results strengthen the suggestion that the early loss of force following eccentric exercise is due to a deficit of excitation-contraction coupling. ABSTRACT: Development of long lasting fatigue (low frequency fatigue; LFF), assessed as the ratio of forces at 20 and 100 Hz stimulation, suggests the early phase of muscle damage caused by eccentric exercise is due to a deficit of excitation-contraction coupling. However, this could be caused by a change of muscle length. Eleven men (21.3 ± 2.0 years) performed 200 maximum eccentric knee extensions (30-110 deg flexion). Force generated by 20 and 100 Hz stimulation and maximum isometric force (MIF) were determined at knee angles 50, 70 and 90 deg before and immediately after the exercise. Vastus lateralis fascicle length (FL) was measured by ultrasound of resting and contracting muscle. Peak MIF (829 ± 119 N) was at 70 deg knee flexion, falling to 486 ± 180 N (P < 0.001) after exercise, but with no change in optimum angle. FLs at rest were unaffected by eccentric exercise, but during contraction they were on average 8.8% (95% CI: 4.1, 13.5%, P = 0.002) longer after exercise. Before exercise, the 20/100 ratio increased with muscle length, from 0.69 ± 0.09 at 50 deg, 0.72 ± 0.05 at 70 deg and 0.80 ± 0.08 at knee angle 90 deg (P < 0.001). After eccentric exercise the 20/100 ratio was reduced to 0.29 ± 0.08 at 50 deg, 0.27 ± 0.04 at 70 deg and 0.34 ± 0.04 at 90 deg (P < 0.001). The 20/100 ratio was relatively insensitive to changes in muscle length and the decrease following eccentric exercise was far greater than might be caused by any changes in muscle length after eccentric exercise. The results show that LFF following eccentric exercise is not due to change in muscle length and strengthen the suggestion that it represents a deficit in excitation-contraction coupling.

Pre-Exercise Rehydration Attenuates Central Fatigability during 2-Min Maximum Voluntary Contraction in Hyperthermia.

Background and objectives: Hyperthermia with dehydration alters several brain structure volumes, mainly by changing plasma osmolality, thus strongly affecting neural functions (cognitive and motor). Here, we aimed to examine whether the prevention of significant dehydration caused by passively induced whole-body hyperthermia attenuates peripheral and/or central fatigability during a sustained 2-min isometric maximal voluntary contraction (MVC). Materials and Methods: Ten healthy and physically active adult men (21 ± 1 years of age) performed an isometric MVC of the knee extensors for 2 min (2-min MVC) under control (CON) conditions, after passive lower-body heating that induced severe whole-body hyperthermia (HT, Tre > 39 °C) with dehydration (HT-D) and after HT with rehydration (HT-RH). Results: In the HT-D trial, the subjects lost 0.94 ± 0.15 kg (1.33% ± 0.13%) of their body weight; in the HT-RH trial, their body weight increased by 0.1 ± 0.42 kg (0.1% ± 0.58%). After lower-body heating, the HT-RH trial (vs. HT-D trial) was accompanied by a significantly lower physiological stress index (6.77 ± 0.98 vs. 7.40 ± 1.46, respectively), heart rate (47.8 ± 9.8 vs. 60.8 ± 13.2 b min-1, respectively), and systolic blood pressure (-12.52 ± 5.1 vs. +2.3 ± 6.4, respectively). During 2-min MVC, hyperthermia (HT-D; HT-RH) resulted in greater central fatigability compared with the CON trial. The voluntary activation of exercising muscles was less depressed in the HT-RH trial compared with the HT-D trial. Over the exercise period, electrically (involuntary) induced torque decreased less in the HT-D trial than in the CON and HT-RH trials. Conclusions: Our results suggest that pre-exercise rehydration might have the immediate positive effect of reducing physiological thermal strain, thus attenuating central fatigability even when exercise is performed during severe (Tre > 39 °C) HT, induced by passive warming of the lower body.

Development of Body-Tissue Temperature-Control Transducer.

The aim of this study was to develop a transducer for non-invasive temperature measurement in deeper tissue layers during tissue cooling. Simulation of the temperature field distribution in human tissues and the transducer were done, and the influence of transducer structure and material properties were studied. Using simulation results, the experimental transducer was designed for temperature measurement in deeper tissue layers during cooling. The temperature measurements with the needle thermometer and the transducer were well correlated at both before tissue cooling r = 0.723 and after cooling r = 0.945, and the temperature difference was no more than ±0.2 °C.

Relationship Between Emotional Intelligence and Health Behaviours among University Students: The Predictive and Moderating Role of Gender.

This study investigated the role of gender as a potential predictor of health behaviour and potential moderator of the relationship between emotional intelligence and health behaviour. This cross-sectional study included 1214 students (597 males and 617 females). Data were collected using the Schutte Self-Report Inventory and the Health Behaviour Checklist. Stepwise multiple regression analysis was executed with the components of health behaviour as the dependent variables to examine the predictive value of the emotional intelligence indicators as the independent variables. Gender predicted all categories of health behaviours. Only one indicator of emotional intelligence, appraisal, predicted the Accident Control and Traffic Risk Taking categories. The emotional intelligence indicator of social skills emerged only as a predictor of Wellness Maintenance and Enhancement in university students. Gender moderates the relationship between all emotional intelligence indicators and health behaviour components except the relationship between Appraisal and Substance Risk Taking and the relationship between Utilization and traffic risk taking.

Effects of a 16-week Pilates exercises training program for isometric trunk extension and flexion strength.

OBJECTIVE: To evaluate the effects of Pilates exercises designed to improve isometric trunk extension and flexion strength of muscles in women with chronic low back pain (cLBP). PARTICIPANTS: Female volunteers with cLBP were divided into an experimental group (EG; n = 27) and a control group (CG; n = 27). INTERVENTION: Pilates exercises were performed twice per week by the EG; the duration of each session was 60 min. The program lasted for 16 weeks; thus patients underwent a total of 32 exercise sessions. RESULTS: The maximum isometric waist bending strength of the EG had improved significantly (p = 0.001) after 16 weeks of the Pilates program. The results of trunk flexion muscle endurance tests significantly depended on the trunk extension muscle endurance before the intervention, and at 1 month (r = 0.723, p < 0.001) and 2 months (r = 0.779, p < 0.001) after the Pilates exercise program. At the end of the 16-week exercise program, cLBP intensity decreased by 2.01 ± 0.8 (p < 0.05) in the EG, and this reduction persisted for 1 month after completion of the program. CONCLUSIONS: At 1 and 2 months after cessation of the Pilates exercise program the pain intensified and the functional state deteriorated much faster than the maximum trunk muscle strength. Therefore, it can be concluded that, to decrease pain and improve functional condition, regular exercise (and not only improved strength and endurance) is required. We established that, although the 16-week lumbar stabilization exercise program increased isometric trunk extension and flexion strength and this increase in strength persisted for 2 months, decreased LBP and improved functional condition endured for only 1 month.

Effects of core stability exercises on multifidus muscles in healthy women and women with chronic low-back pain.

BACKGROUND: Chronic low-back pain (LBP) may be related to decreased lumbar multifidus muscle cross-sectional area (CSA). OBJECTIVE: In this study, core stabilization exercises were designed to enhance neuromuscular control and correct multifidus dysfunction. METHODS: The subjects were healthy women (n = 11) and women with chronic LBP (n = 17). Lumbar multifidus muscle CSAs were measured by ultrasonography. Tests were carried out before training exercises for lumbar stability, and again 4 months and 8 months after training. RESULTS: In women with LBP, the mean multifidus muscle CSA increased by 22% on the right side and 23% on the left side after 8 months of lumbar stabilization training, compared with baseline measurements. In healthy women, mean multifidus muscle CSA increased by 24% on the right side and 23% on the left side, compared with baseline values. CONCLUSIONS: A core stabilization exercise program significantly increased multifidus muscle CSAs in both healthy women and women with chronic LBP.

Effects of estrogen fluctuation during the menstrual cycle on the response to stretch-shortening exercise in females.

The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n = 18; age = 20.2 ± 1.7 yr) participated in this research. The subjects performed one session of 100 maximal drop jumps on day 1 or 2 of the follicular phase and another identical session on day 1 or 2 of the ovulatory phase; the order of the sessions was randomized. Quadriceps femoris muscle peak torque evoked by electrical stimulation and maximal voluntary contraction, muscle pain, and CK activity were measured before and at various times up to 72 h after exercise. It was found that the high estrogen level during the ovulatory phase might be related to an earlier return to baseline muscle strength after strenuous stretch-shortening cycle exercise in that phase compared with the follicular phase. The estrogen effect appears to be highly specific to the damaged site because the differences in most EIMD markers (CK, soreness, and low-frequency fatigue) between the two menstrual cycle phases were small.

Effect of single physical load of different duration and intensity on cognitive function.

UNLABELLED: The aim of this study was to determine the effect of a single physical load of different duration and intensity on cognitive function. MATERIAL AND METHODS: The study population comprised 90 male soldiers. The subjects were randomly divided into two groups: experimental (n=60) and control group (n=30). The soldiers in the experimental group undertook 3 specific loads of different types, durations, and intensities. Attention concentration and tapping tests were carried out, and the reaction time was measured. RESULTS: After the physical load, the soldiers in the experimental group performed the attention concentration test faster, the number of committed mistakes decreased, and the rate of processing information increased as compared to the corresponding values before physical load (all P<0.05). However, the indices of fatigue, such as the tapping test score and reaction time, in the experimental group were found to be worse than before physical loads (P<0.05). No significant changes were observed in the control group of soldiers. CONCLUSION: Despite fatigue, a single physical load of different duration and intensity improved the cognitive function.

Muscle damaging exercise affects isometric force fluctuation as well as intraindividual variability of cognitive function.

Healthy untrained men (N = 11) were asked to perform 10 series of 12 repetitions of knee eccentric extension (EE) at 160 degrees per second. Quadriceps muscle torques evoked by electrical stimulation at 20 Hz (P20) and 100 Hz (P100), maximal voluntary isometric contraction torque (MVC), maximal isokinetic concentric torque (IT) at 30 degrees per second, voluntary activation index (VA), simple reaction time (RTs), complex reaction time (RTc), and torque variability at 30% of MVC were measured before EE, immediately after EE, and 60 min and 24 hr after EE. MVC, IT, P20, P100, and VA decreased significantly after EE and remained depressed 24 hr later. Torque variability increased significantly after EE. Average RTs and RTc did not change after EE, whereas intraindividual variability in RTs and RTc increased significantly after EE.

Peripheral and central fatigue after muscle-damaging exercise is muscle length dependent and inversely related.

Healthy untrained men performed 10 series of 12 knee eccentric extension repetitions (EE) at 160 degrees /s. The maximal voluntary isometric contraction force of the quadriceps muscle, the maximal rate of electrically induced torque development (RTD) and relaxation (RTR), isokinetic concentric torque at 30 degrees /s, the electrostimulation-induced torque at 20 and 100Hz frequencies were established before and after EE at shorter and longer muscle lengths. Besides, voluntary activation (VA) index and central activation ratio (CAR) were tested. There was more peripheral fatigue than central after EE. We established more central fatigue as well as low frequency fatigue at a shorter muscle length compared to the longer muscle length. Relative RTD as well as relative RTR, improved after EE and did not depend on the muscle length. Finally, central fatigue is inversely significantly related with the eccentric torque reduction during eccentric exercise and with the changes in muscle torque induced by low frequency stimulation.

[Influence of heating and cooling on muscle fatigue and recovery]. / Sildymo ir saldymo itaka raumenu nuovargiui ir atsigavimui.

SUMMARY: The aim of the present study was to establish the influence of muscle heating and cooling on knee flexors and extensors during fatiguing exercise. The participants of the study were 10 healthy males aged 19-23 years. The participants of the study were tested with the isokinetic dynamometer. Control measurements were done before the load as well as 10 min, 30 min, 60 min, and 24 h after the load. The participants performed concentric exercise bouts: 50 knee extensions and flexions at the fixed speed of 180 degrees /s, when femoral muscles before concentric load were of normal temperature, were heated or cooled. Creatine kinase activity in blood serum was estimated 1 h before the load and 24 h after it. Internal temperature of the muscle quadriceps femoris after muscle heating for 45 min increased to 39.5+/-0.2 degrees C (P<0.001) and after muscle cooling for 30 min decreased to 32.5+/-0.3 degrees C (P<0.05) as compared to baseline temperature (before heating - 36.9+/-0.1 degrees C, before cooling - 36.8+/-0.2 degrees C). Creatine kinase activity in blood serum 24 h after concentric load was significantly increased as compared to control values. Passive muscle warming increased muscle contraction force of knee extensors, but did not cause any changes either in the rate of muscle fatigue or in the rate of muscle recovery. Muscle cooling did not decrease muscle contraction force and did not increase muscle fatigue resistance. The findings of this study showed that both, muscle warming and muscle cooling, brought about a decrease in an indirect parameter of muscle damage - the amount of creatine kinase 24 h after concentric load.

[Cooling makes recovery of muscle faster after eccentric-concentric than concentric exercise]. / Pasaldymas labiau pagreitina raumens atsigavima po ekscentrinio-koncentrinio fizinio kruvio nei po koncentrinio.

The aim of the study was to establish the influence of muscle cooling on muscle recovery after concentric and eccentric-concentric exercise. Healthy untrained males (n=40) took part in this study. During the first experiment, subjects performed concentric and during the second--eccentric-concentric exercise. During both experiments, the subjects were divided into the groups. In the first group, the muscles of the lower limbs were cooled down after the physical load, while the muscles of the subjects of the second group were not cooled. The rectal, skin, and muscle temperature was repeatedly measured immediately after physical load and after cooling of the muscle. Before exercise and after 2 min and 4, 8, 24, 48, 72 hours after performing exercise, quadriceps muscle strength, generated by electrical stimulation at frequencies of 20 Hz and 50 Hz, and maximal voluntary contraction force were registered. Serum creatine kinase levels were measured before and 24 hours after exercise. In addition, the subjects subjectively rated their muscle pain on a 10-point scale 24, 48, 72 hours after exercise. The results show that cooling applied to muscles after concentric and eccentric-concentric exercise affected the indicators of muscle damage--the activity of creatine kinase was decreased and muscle strength recovered faster. The cooling effect is greater when it is applied after eccentric-concentric exercise.

Dynamics of indirect symptoms of skeletal muscle damage after stretch-shortening exercise.

Healthy untrained men (age 20.4+/-1.7 years, n=20) volunteered to participate in an experiment in order to establish dynamics of indirect symptoms of skeletal muscle damage (ISMD) (decrease in maximal isometric voluntary contraction torque (MVCT) and torque evoked by electrostimulation at different frequencies and at different quadriceps muscle length, height (H) of drop jump (DJ), muscle soreness and creatine kinase (CK) activity in the blood) after 100 DJs from 0.75 m height performed with maximal intensity with an interval of 20s between the jumps (stretch-shortening exercise, SSE). All ISMDs remained even 72 h after SSE (P<0.01-0.001). The muscle experienced greater decrease (P<0.01) in torque evoked by electrostimulation (at low stimulation frequencies and at short muscle length in particular) after SSE than neuromuscular performance (MVCT and H of DJ) which demonstrated secondary decrease (P<0.01) in neuromuscular performance during the first 48 h after SSE. Within 24-72 h after the SSE the subjects felt an acute muscle pain (5-7 points approximately) and the CK activity in the blood was significantly increased up to 1200 IU/L (P<0.001). A significant correlation between decrease in MVCT and H of DJ 24-48 h after SSE on the one hand and muscle soreness registered within 24-48 h after SSE on the other was observed, whereas correlation between the other indirect symptoms of skeletal muscle damage was not significant.