Conditioning Strategies for Human High Performance and Health

Official guidelines state that suitable physical activity is recommended for patients with diabetes mellitus. However, since walking at a rapid pace could be associated with increased plantar pressure and potential foot pain, the footwear condition is particularly important for optimal foot protection in order to reduce the risk of tissue injury and ulceration of diabetic patients. This study aims to analyze foot deformation and plantar pressure distribution at three different walking speeds (slow, normal, and fast walking) in dynamic situations. The dynamic foot shape of 19 female diabetic patients at three walking speeds is obtained by using a novel 4D foot scanning system. Their plantar pressure distributions at the three walking speeds are also measured by using the Pedar in-shoe system. The pressure changes in the toes, metatarsal heads, medial and lateral midfoot, and heel areas are systematically investigated. Although a faster walking speed shows slightly larger foot measurements than the two other walking speeds, the difference is insignificant. The foot measurement changes at the forefoot and heel areas, such as the toe angles and heel width, are found to increase more readily than the measurements at the midfoot. The mean peak plantar pressure shows a significant increase at a faster walking speed with the exception of the midfoot, especially at the forefoot and heel areas. However, the pressure time integral decreases for all of the foot regions with an increase in walking speed. Suitable offloading devices are essential for diabetic patients, particularly during brisk walking. Design features such as medial arch support, wide toe box, and suitable insole material for specific area of the foot (such as polyurethane for forefoot area and ethylene-vinyl acetate for heel area) are essential for diabetic insole/footwear to provide optimal fit and offloading. The findings contribute to enhancing the understanding of foot shape deformation and plantar pressure changes during dynamic situations, thus facilitating the design of footwear/insoles with optimal fit, wear comfort, and foot protection for diabetic patients. Full article

Muscular strength is strongly related to speed and agility tasks, which have been described as the most decisive actions preceding goals in the soccer game. This study aimed to characterize the players’ strength indicators and to analyze the variation associated with age, competition level, and positional role. Eighty-three male soccer players from A team (n = 22), B team (n = 17), U-23 (n = 19), and U-19 (n = 25) participated in this study. Handgrip strength was assessed using a hand dynamometer (Jamar Plus+), countermovement jump (CMJ) and the squat jump (SJ) were evaluated using Optojump Next, and a Biodex System 4 Pro Dynamometer was used to assess the isokinetic strength of knee extension/flexion. Team A players showed increased lower-body strength compared to their peers, mainly through their increased vertical jumping capacity (i.e., CMJ and SJ; ps < 0.019), and superior performance in isokinetic assessments (i.e., peak torque, total work, and average power). Overall, older players outperformed their younger peers regarding vertical jumping, static strength, and average power in isokinetic strength (ps < 0.005). This study emphasizes the superior strength levels of professional soccer players compared with their lower-division peers, even after controlling by age. This information is of great value to sports agents and coaches, underlining the need to design and include strength-specific content during soccer training. Full article

The purpose of this study was to investigate the associations of the timing and nutritional characteristics of bedtime meals with sleep quality in nurses after rotating night shifts. In total, 128 nurses from a university hospital in South Korea participated in this cross-sectional study. Data were collected on the first night of two or three consecutive routine night shifts. Participants recorded all food eaten before going to bed after work. An accelerometer was used to objectively measure sleep quality, and subjective sleep quality was assessed by self-report using the Korean version of the Verran and Snyder-Halpern Sleep Scale. The associations of timing and nutritional characteristics of bedtime meals with sleep quality after night shifts were analyzed using multivariate linear regression. A short time interval between meals and sleep was associated with longer objectively measured total sleep time (β = −0.37, p = 0.002), and the proportion of protein in meals was associated with better objectively measured sleep efficiency (β = 0.31, p = 0.007). The shorter the time interval, the better the subjective sleep quality (β = −0.23, p = 0.048), and high-calorie meals were positively associated with subjective sleep quality (β = 0.23, p = 0.043). Based on our findings, we encourage nurses to have protein-rich meals after night shifts and reduce the delay between meals and sleep. Although high-calorie meals were shown to have a positive effect on subjective sleep quality, it is necessary to confirm this effect through additional research. Full article

The aim of present study was to examine the mediating effect of presenteeism on the relationship between emotional labor and work engagement of coaches for disability sports. A total of 198 coaches in Korea participated in this study. Participants responded a survey measuring emotional labor, presenteeism, and work engagement. After analyzing the correlation between each variable, the mediation model was verified through structural equation model analysis. The results reveal that emotional labor of coaches for disability sports positively predicted their work engagement, but negatively predicted presenteeism. In addition, the participants’ presenteeism can have a negative effect on their work engagement. Moreover, completing work in presenteeism was found to mediate the relationship between the deep acting and surface acting in emotional labor and work engagement of disability sports coaches. Full article

This study investigated the effectiveness of electrical muscle stimulation (EMS) with resistance exercise training (ERT) and resistance exercise training (RT) on physical and brain function in middle-aged and older women. Method: Forty-eight participants were randomly allocated into three groups: (i) ERT (n = 16), (ii) RT (n = 16), and (iii) control group (n = 16). The intervention session was 50 min long and performed three times/week for four weeks. The ERT group performed quadriceps setting, straight leg raises, and ankle pump exercises while constantly receiving EMS on their quadriceps muscle on both legs. The RT group performed the same exercise without EMS. Physical function was measured using skeletal muscle mass index (SMI), handgrip strength, gait speed, five times sit-to-stand test (FTSS) and timed up-and-go test (TUG). Brain function was assessed with electroencephalogram measurement of whole brain activity. Results: After four-week intervention, significant improvements were observed in SMI (p < 0.01), phase angle (p < 0.05), and gait speed (p < 0.05) in the ERT group compared to the control group. ERT also increased muscle strength (p < 0.05) and mobility in lower limbs as observed in FTSS and TUG tests (p < 0.05) at post-intervention compared to the baseline. In the ERT group, significant positive changes were observed in Beta1 band power, Theta band power, and Alpha1 band whole brain connectivity (p < 0.005) compared to the control group. Conclusions: Our findings showed that ERT can improve muscle and brain function in middle-aged and older adults during a four-week intervention program whereas significant improvements were not observed with RT. Therefore might be one of the feasible alternative intervention to RT for the prevention of muscle loss whilst improving brain function for middle-aged and older population. Full article

Aging and regular exercise may have opposite effects on brain health, and although oxidative stress and sirtuins may be involved in these effects, studies on this topic are limited. Accordingly, the present study aimed to verify the effect of exercise training on oxidant–antioxidant balance, neurotrophic factors, blood–brain barrier permeability, and sirtuins in young-old and old-old women. The study participants were 12 women aged 65–74 years (Young-Old group) and 12 women aged 75–84 years (Old-Old group). All of the selected participants performed exercise training consisting of treadmill walking and resistance band exercise three times a week for 12 weeks. Blood samples were collected before and after exercise training to analyze serum oxidant–antioxidant markers (reactive oxygen species [ROS], superoxide dismutase [SOD]), neurotrophic factor (brain-derived neurotrophic factor [BDNF], vascular endothelial growth factor [VEGF]) levels, and blood–brain barrier permeability marker (S100 calcium-binding protein β [S100β], matrix metalloproteinase-9 [MMP-9]) levels, and sirtuin (SIRT-1, SIRT-2, SIRT-3) levels. The Young-Old group showed significantly increased SOD, BDNF, VEGF, SIRT-1, and SIRT-3 levels after training in comparison with the levels before training (p < 0.05), and a significantly higher BDNF level than the Old-Old group after training (p < 0.05). On the other hand, the Old-Old group showed significantly higher SIRT-1 levels after training in comparison with the levels before training (p < 0.05). Thus, exercise training may be effective in increasing the levels of neurotropic factors and reducing blood–brain barrier permeability in the elderly women, and increased antioxidant capacity and elevated levels of sirtuins are believed to play a major role in these effects. The positive effect of exercise may be greater in participants of relatively young age. Full article

A randomized controlled trial (RCT) was conducted to evaluate the effect of fermented sarco oysters (FSO) on muscle strength in postmenopausal females with low muscle mass. Fifty-two female participants were randomly divided into the experiment group (EG) or control group (CG). For 12 weeks, the EG was subjected to 1000 mg of FSO extract daily while the CG consumed the placebo extract. The muscle extension and flexion at an angular velocity of 60°/s and with respect to grip strength, body composition, and muscle growth-related blood factors were measured at the baseline and after the trial. The difference in the quadriceps muscle extension at an angular velocity of 60°/s, grip strength on both the left and right side, and insulin-like growth factor-1(IGF-1) between groups were significantly higher in the EG compared with the CG. However, no differences were found in body composition, blood pyruvate, lactate, or high-sensitivity C-reactive protein (hsCRP) concentration between the two groups. In conclusion, FSO supplements may improve muscle strength in postmenopausal females with relatively reduced muscle strength without a change in muscle mass. Full article

Background: Alterations in the lower limb kinematics and kinetics of diabetic patients have been reported in previous studies. Inappropriate choices of orthopedic insole materials, however, fail to prevent diabetic foot ulcers and modify abnormal gait. The aim of this study was to quantitatively compare the effects of contoured insoles with different materials on the kinematics of and kinetics changes in the diabetic elderly during gait. Methods: There were 21 diabetic patients who participated in this study. Three-dimensional (3D) experimental contoured insoles constructed of soft (i.e., Nora Lunalastik EVA and PORON^® Medical 4708) and rigid (i.e., Nora Lunalight A fresh and Pe-Lite) materials with Langer Biomechanics longitudinal PPT^® arch pads were adopted. An eight-camera motion capture system (VICON), two force plates, and an insole measurement system—Pedar^® with 99 sensors—were utilized to obtain the kinematics and kinetics data. The plug-in lower body gait model landmarks were used for dynamic data acquisition during gait. The corresponding data from five gait cycles were selected and calculated. Results: The range of motions (ROMs) of the ankle joint (p = 0.001) and knee joint (p = 0.044) were significantly influenced when the contoured insoles were worn in comparison to the barefoot condition. The joint moments of the lower limbs with maximum ankle plantarflexion during the loading response and maximum knee and hip flexions were significantly influenced by the use of contoured insoles with different materials in the diabetic elderly. The peak plantar pressure (PPP) of the forefoot (p < 0.001), midfoot (p = 0.009), and rearfoot (p < 0.001) was significantly offloaded by the contoured insoles during the stance phase, whilst the PPP of the rearfoot (p < 0.001) was significantly offloaded during the swing phase. Conclusions: The contoured insoles, especially those constructed with soft materials, significantly offloaded the PPP during gait—hence accommodating certain abnormal gait patterns more effectively compared to going barefoot. Full article

Exercise can induce anti-inflammatory and antioxidant effects, for which regulation of sirtuins (SIRTs) may be a major consideration for exercise prescription. The purpose of this study was to investigate the effects of acute aerobic exercise, in particular its intensity, on systemic oxidative stress, inflammatory responses, and SIRT levels. Twenty healthy, untrained males were recruited and randomly assigned to moderate-intensity (MI, 65% VO₂max, n = 10) and high-intensity (HI, 85% VO₂max, n = 10) exercise. Blood samples were obtained pre-, immediately post-, and 1 h post-exercise for measurements of malonaldehyde (MDA), superoxide dis-mutase (SOD), interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, SIRT-1, SIRT-2, and SIRT-3. Overall, MDA, SOD, IL-6, SIRT-1, and SIRT-3 levels were significantly increased at post-exercise compared with pre-exercise regardless of exercise intensity (p < 0.05). The HI group had significantly higher MDA, SOD, and IL-6 levels than the MI group at post-exercise (p < 0.05), whereas no significant differences were observed in the IL-1β, TNF-α, and SIRT-2 levels (p > 0.05). Altogether, these findings suggest that exercise-induced oxidative stress and inflammatory responses may be dependent on exercise intensity. Moreover, activation of inflammatory cytokines and SIRT family members may be dependent on the intensity of the exercise. Full article

This study examined the effect of athletes’ competition conditions, personal performance level, and attributions toward winning or losing on the relationship between observational learning (OL) and self-efficacy (SE) based on social cognitive theory and social comparison theory. Study 1 verified the validity and reliability of the Korean versions of the Functions of Observational Learning Questionnaire (FOLQ) and the SE Questionnaire. Study 2 investigated differences in the degree to which OL predicts SE in different pressure conditions and personal performance levels. The results showed that OL increased SE in high-performing athletes in high-pressure games and better predicted SE in low-performing athletes in low-pressure games. Study 3 tested the double-mediating effects of effect and OL on the effect of attributions about winning or losing on SE. The results showed that a stronger perception that the cause of winning was internal was associated with increased pride, OL, and SE. Full article

This study was conducted to investigate the changes in the autonomic nervous system in middle-aged women induced by aerobic and resistance exercise. A randomized controlled design was adopted; 22 premenopausal middle-aged women were divided into the resistance training and aerobic exercise groups (n = 11 each). Each group followed a specific 60 min exercise program three times a week for 12 weeks. The participants’ heart rate variability (HRV) was measured to analyze the low(LF)- and high-frequency (HF) activity, and the LF/HF ratio was calculated to examine the autonomic nervous system’s activities. A repeated-measures analysis of variance was used to analyze the effects of resistance and aerobic exercise. LF activity significantly increased in both the resistance training (p < 0.001) and aerobic exercise (p < 0.5) groups, indicating a significant variation according to time effect. HF activity was significantly increased only in resistance training (p < 0.001) with a significant variation in time (p < 0.001) and an interaction effect (p < 0.01). The LF/HF ratio did not vary significantly in either group. The findings in this study suggest that both aerobic exercise and resistance training were effective for sympathetic nerve activities in middle-aged women and that the effects on the sympathetic and parasympathetic activities were greater for resistance training. Full article

In this study, the effects of a 12-week exercise program combining aerobic and resistance training on high-fat diet-induced obese Sprague Dawley (SD) rats after the injection of beta-amyloid into the cerebral ventricle were investigated. Changes in physical fitness, cognitive function, blood levels of beta-amyloid and metabolic factors, and protein expressions of neurotrophic factors related to brain function such as BDNF (brain-derived neurotrophic factor) in the quadriceps femoris, hippocampus, and cerebral cortex were analyzed. The subjects were thirty-two 10-week-old SD rats (DBL Co., Ltd., Seoul, Korea). The rats were randomized into four groups: β-Non-Ex group (n = 8) with induced obesity and βA25-35 injection into the cerebral ventricle through stereotactic biopsy; β-Ex group (n = 8) with induced obesity, βA25-35 injection, and exercise; S-Non-Ex group (n = 8) with an injection of saline in lieu of βA25-35 as the control; and S-Ex group (n = 8) with saline injection and exercise. The 12-week exercise program combined aerobic training and resistance training. As for protein expressions of the factors related to brain function, the combined exercise program was shown to have a clear effect on activating the following factors: PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha), FNDC5 (fibronectin type III domain-containing protein 5), and BDNF in the quadriceps femoris; TrkB (Tropomyosin receptor kinase B), FNDC5, and BDNF in the hippocampus; PGC-1α, FNDC5, and BDNF in the cerebral cortex. The protein expression of β-amyloid in the cerebral cortex was significantly lower in the β-Ex group than in the β-Non-Ex group (p < 0.05). The 12-week intervention with the combined exercise program of aerobic and resistance training was shown to improve cardiopulmonary function, muscular endurance, and short-term memory. The results demonstrate a set of positive effects of the combined exercise program, which were presumed to have arisen mainly due to its alleviating effect on β-amyloid plaques, the main cause of reduced brain function, as well as the promotion of protein expressions of PGC-1α, FNDC5, and BDNF in the quadriceps femoris, hippocampus, and cerebral cortex. Full article

The purpose of this study was to investigate whether there is a gender-specific difference in the indirect effect of perceived coaching behaviors of Taekwondo Poomsae athletes on performance mediated by basic psychological needs. To this end, a survey was conducted to collect data from 474 Taekwondo Poomsae athletes (male = 285). Based on the collected data, analysis of basic descriptive statistics and confirmatory factor analysis were performed, and PROCESS was used to test the proposed model of multi mediated moderation. For female athletes, there was an indirect effect of controlling coaching behaviors resulting in performance improvement mediated by autonomy, but this effect was not observed in male athletes. The findings of this study indicate that different mental conditioning strategies should be applied in consideration of athletes’ gender to improve coaches’ methods of instruction and ultimately improve performance in Taekwondo Poomsae. Full article

Maintenance of positive psychological conditioning can be a key factor in eliciting high human performance. In particular, perception of error forms a causal relationship with challenges regarding task performance. Therefore, this study aimed to investigate the mediation effect of expectancy value in the relationship between the perception of error and challenge using the Phantom Model through quantitative research. This study analyzed the causal relationship between perception of error, expectancy value, and challenge in 423 young Taekwondo athletes. Frequency analysis, confirmatory factor analysis, correlation analysis, and structural equation modeling were performed on the collected data using Jamovi 1.0.1 and AMOS 23.0 statistical programs to verify the hypothesis. The challenge demonstrated a significant difference in relation to the perception of error. These results demonstrated that the perception of error not only directly affected one’s challenge but also explained the increased challenge by mediating expectations for success and subjective values. Hence, the positive perception of error increased the athletes’ expectancy value and challenge. Full article

Coaching is a stressful occupation, with expectations that are physically and psychologically demanding. Coaches are highly susceptible to occupational burnout and presenteeism, which ultimately affects the entire sporting community. In this study, coaching stress was evaluated by surveying taekwondo coaches to analyze the contributions of unique cultural predispositions and workplace conditions (environmental) to coach stress, burnout, and presenteeism. We verified the positive correlation between workplace conditions, burnout, and presenteeism for 210 taekwondo coaches; performed frequency, correlation, and confirmatory analysis using the compiled data; and the discussed the results within the framework of a formulated structural equation model. The research results are as follows. First, the workplace conditions of taekwondo coaches had a negative effect on burnout syndrome. Second, the workplace conditions of taekwondo coaches had a negative effect on presenteeism. Lastly, burnout of taekwondo coaches had a significant effect on presenteeism. Therefore, coaches’ burnout decreases as their workplace conditions improve, and presenteeism decreases as their burnout increases in controlled workplace conditions. Full article