Soil habitat condition shapes Tamarix chinensis community diversity in the coastal saline-alkali soils.

Introduction: Unfavorable coastal saline-alkali soil habitats degrade plant community diversity and reduce terrestrial ecological functions. Previous studies have been conducted on the mechanisms by which certain saline-alkali soil properties determine plant community diversity, however, how those properties synergistically affect plant community diversity remains unclear. Methods: Here, 36 plots of typical Tamarix chinensis communities were investigated for a range of parameters at three different distances (10, 20, and 40 km) from the coastline in the Yellow River Delta between 2020 and 2022, and corresponding soil samples were taken and analyzed. Results and discussion: Our results suggest that although T. chinensis density, ground diameter, and canopy coverage significantly increased (P<0.05) with increasing distance from the coast, the communities with the most plant species were found at 10 to 20 km distance from the coastline, indicating the effects of soil habitat on T. chinensis community diversity. Simpson dominance (species dominance), Margalef (species richness), and Pielou indices (species evenness) differed significantly among the three distances (P<0.05) and were significantly correlated with soil sand content, mean soil moisture, and electrical conductivity (P<0.05), indicating that soil texture, water, and salinity were the main factors governing T. chinensis community diversity. Principal component analysis (PCA) was performed to construct an integrated soil habitat index (SHI) representing the synthesis of the soil texture-water-salinity condition. The estimated SHI quantified a 64.2% variation in the synthetic soil texture-water-salinity condition and was significantly higher at the 10 km distance than at the 40 and 20 km distances. The SHI linearly predicted T. chinensis community diversity (R2 = 0.12-0.17, P<0.05), suggesting that greater SHI (coarser soil texture, wetter soil moisture regime, and higher soil salinity) was found closer to the coast and coincided with higher species dominance and evenness and lower species richness in the T. chinensis community. These findings on the relationship between T. chinensis communities and soil habitat conditions will be valuable in planning the restoration and protection of the ecological functions of T. chinensis shrubs in the Yellow River Delta.

Biomechanical characteristics of 2 different posterior fixation methods of bilateral pedicle screws: A finite element analysis.

BACKGROUND: To explore the biomechanical characteristics of 2 posterior bilateral pedicle screw fixation methods using finite element analysis. METHODS: A normal L3-5 finite element model was established. Based on the verification of its effectiveness, 2 different posterior internal fixation methods were simulated: bilateral pedicle screws (model A) were placed in the L3 and L5 vertebral bodies, and bilateral pedicle screws (model B) were placed in the L3, L4, and L5 vertebral bodies. The stability and stress differences of intervertebral discs, endplates, screws, and rods between models were compared. RESULTS: Compared with the normal model, the maximum stress of the range of motion, intervertebral disc, and endplate of the 2 models decreased significantly. Under the 6 working conditions, the 2 internal fixation methods have similar effects on the stress of the endplate and intervertebral disc, but the maximum stress of the screws and rods of model B is smaller than that of model A. CONCLUSIONS: Based on these results, it was found that bilateral pedicle screw fixation in 2 vertebrae L3 and L5 can achieve similar stability as bilateral pedicle screw fixation in 3 vertebrae L3, L4, and L5. However, the maximum stress of the screw and rod in model B is less than that in model A, so this internal fixation method can effectively reduce the risk of fracture. The 3-dimensional finite element model established in this study is in line with the biomechanical characteristics of the spine and can be used for further studies on spinal column biomechanics. This information can serve as a reference for clinicians for surgical selection.

Effect of the Innovative Running Shoes With the Special Midsole Structure on the Female Runners' Lower Limb Biomechanics.

The study aimed to research the effects of innovative running shoes (a high heel-to-toe drop and special structure of midsole) on the biomechanics of the lower limbs and perceptual sensitivity in female runners. Fifteen healthy female runners were recruited to run through a 145-m runway with planted force plates at one peculiar speed (3.6 m/s ± 5%) with two kinds of shoe conditions (innovative running shoes vs. normal running shoes) while getting biomechanical data. The perception of shoe characteristics was assessed simultaneously through a 15-cm visual analog scale. The statistical parametric mapping technique calculated the time-series parameters. Regarding 0D parameters, the ankle dorsiflexion angle of innovative running shoes at touchdown was higher, and the peak dorsiflexion angle, range of motion, peak dorsiflexion velocity, and plantarflexion moment on the metatarsophalangeal joint of innovative running shoes during running were significantly smaller than those of normal running shoes (all p < 0.001). In addition, the braking phase and the time of peak vertical force 1 of innovative running shoes were found to be longer than those of normal running shoes (both p < 0.05). Meanwhile, the average vertical loading rate 1, peak vertical loading rate 1, peak braking force, and peak vertical force 1 in the innovative running shoes were lower than those of the normal running shoes during running (both p < 0.01). The statistical parametric mapping analysis exhibited a higher ankle dorsiflexion angle (0-4%, p < 0.05), a smaller knee internal rotation angle (0-6%, p < 0.05) (63-72%, p < 0.05), a decreased vertical ground reaction force (11-17%, p = 0.009), and braking anteroposterior ground reaction force (22-27%, p = 0.043) for innovative running shoes than normal running shoes. Runners were able to perceive the cushioning of innovative running shoes was better than that of normal running shoes. These findings suggested combining the high offset and structure of the midsole would benefit the industrial utilization of shoe producers in light of reducing the risk of running injuries for female runners.

The Physiological and Psychological Benefits of Dance and its Effects on Children and Adolescents: A Systematic Review.

Background: The aim of this review was to examine the physiological and psychological benefits of dance and its effects on children and adolescents. We consider the therapeutic benefits of dance and outline the potential of dance as an alternative therapy for certain pathologies and medical disorders. Secondly, we summarize the types of dances used in physical interventions, and comment on the methodologies used. Finally, we consider the use of dance as a different exercise modality that may have benefits for increased physical activity generally, and for increased physical education provision in schools. Methods: A structured search strategy was conducted using the databases of PubMed, MEDLINE, Web of science, PsycARTICLES, and Social Science database. This review used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews. Studies that were published in the past 20 years were considered for inclusion. All written publications were searched for in English, and all articles included in this review were peer reviewed full papers. Conclusion: The key findings from this review indicate that dance is a feasible alternative to traditional physical activity. The findings also indicate that dance provides physiological and psychological benefits to healthy and medically compromised populations. Implementation of dance programs in schools and society generally needs serious consideration by policy makers. We hope that the results of this review stimulate debate and provide the necessary evidence to profile dance as a viable alternative medium of physical activity. Comprehensive and integrated changes will be needed including economical and legislative support from politicians and associated governmental agencies. The findings reported here are important and have implications for health policy change, reconfiguration, and implementation.

Biomechanical Characteristics of the Typically Developing Toddler Gait: A Narrative Review.

Independent ambulation is one of the most important motor skills in typically developing toddlers. Gait analysis is a key evaluation method in basic and clinical research. A narrative review on the literature of toddler gait development was conducted following inclusion criteria, explicitly including the factors of English article, age range, no external intervention during the experimental process of studies involved, the non-symptomatic toddler, and no pathological gait. Studies about toddlers' morphological, physiological, and biomechanical aspects at this developmental stage were identified. Remarkable gait characteristics and specific development rules of toddlers at different ages were reported. Changes in gait biomechanics are age and walking experience-dependent. Gait patterns are related to the maturation of the neuro and musculoskeletal systems. This review thus provides critical and theoretical information and the nature of toddler walking development for clinicians and other scientific researchers. Future studies may systematically recruit subjects with more explicit criteria with larger samples for longitudinal studies. A particular design could be conducted to analyze empirically before practical application. Additionally, the influence of external interventions on the development of toddler gait may need consideration for gait development in the toddler cohort.

Ground Reaction Force Differences between Bionic Shoes and Neutral Running Shoes in Recreational Male Runners before and after a 5 km Run.

Running-related injuries are common among runners. Recent studies in footwear have shown that designs of shoes can potentially affect sports performance and risk of injury. Bionic shoes combine the functions of barefoot running and foot protection and incorporate traditional unstable structures based on bionic science. The purpose of this study was to investigate ground reaction force (GRF) differences for a 5 km run and how bionic shoes affect GRFs. Sixteen male recreational runners volunteered to participate in this study and finished two 5 km running sessions (a neutral shoe session and a bionic shoe session). Two-way repeated-measures ANOVAs were performed to determine the differences in GRFs. In the analysis of the footwear conditions of runners, bionic shoes showed significant decreases in vertical impulse, peak propulsive force, propulsive impulse, and contact time, while the braking impulse and vertical instantaneous loading rate (VILR) increased significantly compared to the neutral shoes. Main effects for a 5 km run were also observed at vertical GRFs and anterior-posterior GRFs. The increases of peak vertical impact force, vertical average loading rate (VALR), VILR, peak braking force and braking impulse were observed in post-5 km running trials and a reduction in peak propulsive force and propulsive impulse. The interaction effects existed in VILR and contact time. The results suggest that bionic shoes may benefit runners with decreasing injury risk during running. The findings of the present study may help to understand the effects of footwear design during prolonged running, thereby providing valuable information for reducing the risk of running injuries.

Kinematic Comparison on Lower Limb Kicking Action of Fetuses in Different Gestational Weeks: A Pilot Study.

The fetal movements during different gestational weeks are essential for normal musculoskeletal development. The kinematic characteristics of fetuses with small differences in gestational weeks may be different and important. Ultrasonographic videos of fetal kicking action and plantarflexion action were collected from three healthy pregnant women (24, 27, and 30 gestational weeks) with normal fetal development. The kinematic characteristics, including angular range and angular velocity, were analyzed. These kinematic parameters were measured using simi motion. The final knee angle was found to decrease with progressive gestational weeks. Compared with 24 w, the knee joint angle at 27 w and 30 w was significantly reduced at the end of a kick-type movement (p < 0.01). Except for the mean angular velocity of the knee joint, there were no significant differences in the other conditions. The value at 30 w for mean angular velocity was significantly higher than that at 24 w (p = 0.02). In the ankle joint, no significant differences were observed between different conditions. Therefore, we can conclude that there was no significant difference in the kinematic characteristics of the ankle joint for small gestational age gaps, but there was a significant difference in the knee joint. As the gestation weeks increase, the range of kicking motion tends to decrease. The reason may be that with the increase of gestational weeks, fetal lower limb musculoskeletal development is gradually enhanced; the slower growth rate indicates that development reaches a peak level in weeks 24 to 30.

Salivary endocrine response following a maximal incremental cycling protocol with local vibration.

The aim of this study was to compare the effects of vibration (Vib versus noVib) during a maximal graded cycling exercise on hormonal response, precisely on cortisol (C) and testosterone (T). Twelve active males (25 ± 5yrs; 181 ± 5cm; 80.7 ± 11.1kg) randomly performed two maximal incremental cycling tests on two separate days and at the same time of the day (09:00). The protocol consisted of incremental steps of 3 min duration performed on a PowerBIKETM that induces vibration cycling. The study was a repeated measures design and participants performed the test with and without vibration. Gas exchange and heart rate (HR) were continuously assessed and blood lactate (Bla) was recorded at the end of each incremental stage. Saliva samples were collected before and immediately after the test, and analysed for (C) and (T). The results show that C and T increased in both cycling conditions; however, the C's magnitude of change was significantly higher by 83% after Vib cycling in comparison to the no Vib (p = 0.014), whereas the T's magnitude of change were not statistically different between trials (p = 0.715). Vibration induced a decrease of the T/C ratio (p = 0.046) but no significant changes were observed following noVib (p = 0.476). As a conclusion, the investigation suggests that adding mechanical vibration to cycling may potentiate a catabolic exercise-induced state, which could have potential clinical implications in rehabilitation and injury treatment. Sport experts should take this message home to carefully plan the recovery process and time during training and competitions.

Vibration Cycling Did Not Affect Energy Demands Compared to Normal Cycling During Maximal Graded Test.

The aim of this study was to compare the physiological responses between a vibration induced cycling step protocol (Vib) and normal cycling (without vibration, no-Vib). Eighteen moderate trained males (age 24.1 ± 4.3 years; weight 76.5 ± 10.5 kg; height 178.0 ± 6.4 cm) have participated in this study. They randomly performed two gradual maximal exercise tests on two separate days using a new bike that automatically induces vibration cycling and the Corival cycle ergometer. The choice of two different bikes was made because of the impossibility to recreate the same power output without altering the cycling cadence on the vibration Bike. Both protocols were matched for power output and cycling cadence incrementations. Oxygen uptake (VO2), carbon dioxide production (VCO2), ventilation (VE), heart rate (HR), blood lactate and rating of perceived exertion (RPE) during each stage were continuously recorded. No statistical differences were founded for all variables when comparing the Vib to no-Vib trials, except a higher ventilation during the vibration trial at submaximal levels. The results of this study do not confirm those of previous studies stated that Vib increased metabolic demands during cycling exercise. Added vibration stimulus to an incremental cycling protocol does not affect physiological parameters.