RESUMEN
Objective@#To understand the situation of mosquito larva breeding and adult mosquito density among schools in Yangpu District, Shanghai Municipality before the start of the fall semester, so as to provide insights into mosquito prevention and control in schools.@*Methods@#A stratified sampling method was used to select four schools each from universities, primary and secondary schools, and preschool institutions as survey sites. A survey of mosquito larva breeding sites and adult mosquito density was carried out in August each year from 2021 to 2023. The mosquito larva breeding sites in small and large water bodies were investigated by visual inspection and spoon trapping methods, and adult mosquito density was investigated by human-induced stinging method. The positive rate of mosquito larva breeding sites and adult mosquito landing index were analyzed.@*Results@#Totally 1 253 mosquito larva breeding sites were investigated from 2021 to 2023, and the positive rate was 4.07% (51 positive sites). The positive rates of mosquito larva breeding sites in universities, primary and secondary schools and preschool institutions were 2.36%, 4.05% and 8.30%, respectively. The top three positive breeding sites in small water bodies were tyres (6.67%), small stagnant water in green belts (6.04%) and unused containers (5.92%), and Aedes albopictus was the dominant species (97.21%). The top three positive breeding sites in large water bodies were rainwater wells (3.90%), landscape water bodies (3.45%) and sewage wells (3.23%), and Culex pipiens pallens and Aedes albopictus each accounted for 50.00%. A total of 200 adult mosquitoes were captured from 2021 to 2023, with Aedes albopictus being dominant (93.00%). The total landing index decreased and then rebounded slightly from 2021 to 2023, with the highest seen in 2021 as 1.78 mosquitoes/0.5 hours per person. The highest mean adult mosquito landing index was 1.17 mosquitoes/0.5 hours per person in preschool institutions.@*Conclusions@#The positive rates of mosquito larva breeding sites and landing index of adult mosquitoes among schools in Yangpu District before the start of the fall semester from 2021 to 2023 were higher than the relevant provisions of the Shanghai municipal local standards. Aedes albopictus was the dominant species. Mosquito surveillance in schools should be carried out on a regular basis and hygiene management should be strengthened.
RESUMEN
BACKGROUND:The landing test can effectively observe the biomechanical indexes of the lower limbs of patients with chronic ankle instability,analyze the balance adjustment strategies that affect the stability of chronic ankle instability posture,and provide a valuable reference for chronic ankle instability patients to avoid re-injury and clinical rehabilitation after injury. OBJECTIVE:To analyze the effects of vision on the balance of chronic ankle instability and the changes in balance adjustment strategies by observing the kinematics and kinetics of chronic ankle instability patients during landing with and without vision. METHODS:Totally 31 patients with chronic ankle instability landed on a single leg from a 40 cm platform with their eyes open and closed.The dynamic and kinematic data during the landing process were collected using a three-dimensional motion capture system.The difference in landing between the healthy and the ill side legs under the two conditions was compared by paired t-test. RESULTS AND CONCLUSION:(1)Dynamic indexes:The relative value of the peak ground reaction force in the front,rear and vertical directions of the affected ankle joint when eyes were closed was greater than that when eyes were open,and the peak ground reaction force in the vertical direction appeared later than that when eyes were open(P<0.05).(2)Kinematics indexes:The flexion angle of the knee of the healthy and affected sides when touching the ground was greater under the condition of closed eyes than under the condition of open eyes(P<0.05).The maximum flexion angle and feedforward angle of the affected knee and ankle were greater than those of the affected side with eyes open(P<0.05).The time of landing stability was longer than that of eye opening(P<0.05).(3)It is indicated that under the condition of removing visual input,the peak of ground reaction force increases,the contact angle joint increases,and the time to stabilization of chronic ankle instability is prolonged during landing in patients with chronic ankle instability,which increases the probability of landing injury.Visual maintenance of the balance of chronic ankle instability patients cannot compensate for the vestibular sense and proprioception.
RESUMEN
BACKGROUND:The landing error scoring system test is a standard for assessing the risk of non-contact injuries and has not yet been developed for Chinese college soccer programs. OBJECTIVE:To establish a test evaluation standard for the landing error scoring system to provide a basis for evaluating the risk of non-contact injuries in college soccer students. METHODS:A prospective cohort study was designed in which 219 athletes from 10 college soccer teams were tested with the standard landing error scoring system,and the subjects were followed up by questionnaires and medical examinations for non-contact injuries of the lower extremities and trunk for 1 year after testing to determine sex differences and assessment criteria for the landing error scoring system test indicators. RESULTS AND CONCLUSION:The total score of the landing error scoring system was(8.22±1.65)points for 219 subjects,(8.29±1.74)for males and(8.07±1.44)for females,with no significant difference between males and females(P>0.05).Within 1 year after the test,the overall injury rate of 219 subjects was 10.05%and the morbidity rate was 15.98%;the injury rate of male subjects with non-contact injury of the lower limbs and trunk was 12.75%and the morbidity rate was 20.13%;the injury rate of female subjects with non-contact injury of the lower limbs and trunk was 4.29%and the morbidity rate was 7.14%.There were no significant differences in the injury rate between men and women(P<0.05).The total score of the landing error scoring system was higher in the injury group than in the non-injury group[(9.50±1.14)vs.(8.08±1.64),P<0.01];for male subjects,the total score of the landing error scoring system was higher in the injury group than in the non-injury group[(9.63±1.12)vs.(8.09±1.73),P<0.01].The area under the curve for the total score of the landing error scoring system was 0.773(P=0.000),which had a diagnostic value for the risk of non-contact injury of the lower extremities and trunk in male subjects,with a best cut-off point of 8.5,sensitivity of 0.842,specificity of 0.623,positive likelihood ratio of 2.233,negative likelihood ratio of 0.254,relative risk factor of 8.400,and odds ratio of 8.816;the total score of the landing error scoring system was not applicable for assessing the risk of non-contact injury of the lower extremities and trunk in female subjects.To conclude,the landing error scoring system test can be used as a criterion to assess the risk of non-contact injury to the lower extremity and trunk in Chinese college male soccer players,with an optimal cut-off point of 8.5.The risk of non-contact injury to the lower extremity and trunk is 8.40 times higher in male athletes with a landing error scoring system test score of≥8.5 than in male athletes with a score of<8.5.
RESUMEN
BACKGROUND:Studies have shown that poor dynamic postural control may lead to abnormal movement patterns during exercise,which may increase the risk of lower limb joint and anterior cruciate ligament injury.The stability of the body core is the basis of good dynamic postural control. OBJECTIVE:To investigate the effects of core stability training on dynamic postural control and risk of injury in landing movements,and to compare the differences in training effects between genders. METHODS:Thirty-five college students(male=19,female=16)were recruited for 6 weeks of core stability training.The results of the Y balance test,trunk extensor endurance test,trunk flexor endurance test,lateral bridge endurance test,and landing error scoring system were analyzed before and after training. RESULTS AND CONCLUSION:The 6-week core stability training could improve trunk extensor endurance(P＜0.001),flexor endurance(P＜0.001),and lateral abdominal muscle endurance(P＜0.001).Core stability training could improve forward distance(P=0.026),backward inward distance(P＜0.001),backward outward distance(P=0.005)and comprehensive score(P＜0.001)of Y balance test for male and female college students.Landing error scoring system scores of both male and female college students significantly decreased after 6 weeks of core stability training(P＜0.001)while increasing knee(P＜0.001)and hip flexion angles(P＜0.001),decreasing knee valgus angle(P＜0.001)at the moment of touchdown,and could increase the maximum knee flexion angle(P＜0.001)and decrease the maximum knee valgus angle(P＜0.001).It is concluded that core stability training improves dynamic postural control and improves landing movement patterns,suggesting that it may help reduce the risk of anterior cruciate ligament injury.There are no sex differences in core stability training in terms of increased trunk flexor endurance,lateral bridge muscle group endurance,improved dynamic postural control,and reduced risk of anterior cruciate ligament injury.
RESUMEN
BACKGROUND:Transcranial direct current stimulation(tDCS),as a non-invasive brain stimulation technique,can enhance human muscle strength or improve single-leg landing stability instantly,but no relevant research has demonstrated this yet. OBJECTIVE:To investigate the effect of tDCS on the stability of single-leg landings in human subjects. METHODS:Male undergraduate students from Wuhan Sports University were recruited as study participants.They were divided into two groups,A(n=6)and B(n=5),using a random number table.Group A underwent a sham stimulation session followed by a 3-day washout period,after which they received tDCS.Conversely,Group B received tDCS initially,followed by a 3-day washout period,and subsequently underwent the sham stimulation session.Following the respective stimulation sessions,an immediate single-leg landing test was administered to assess and collect biomechanical parameters.Data resulting from the tDCS intervention were aggregated and analyzed as the experimental group dataset,whereas data stemming from the sham stimulation were consolidated as the control group dataset. RESULTS AND CONCLUSION:Regarding core stability,the tDCS intervention showed a significant interaction with landing height on the maximal trunk flexion angle(P＜0.05).A paired comparison of the data showed a significant decrease in the maximum trunk flexion angle following true stimulation compared to sham stimulation at a 30-cm landing height.Additionally,the tDCS intervention had a significant main effect on the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity(P＜0.05).Following true stimulation,there was a significant decrease in the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity compared to sham stimulation.In terms of lower limb joint stability,the tDCS intervention had a significant main effect on the maximum dynamic ankle valgus angle(P＜0.05).This resulted in a significant decrease in the angle following true stimulation compared to sham stimulation.In addition,the tDCS intervention had a significant main effect on the peak muscle activation of the lateral head of the gastrocnemius lateralis(P＜0.05).This showed a significant increase after true stimulation compared to sham stimulation.An interaction between the tDCS intervention and landing height was observed for the peak muscle activation of the tibialis anterior(P＜0.05).Paired comparison analyses revealed a significant increase in muscle activation after true stimulation specifically at a 60-cm landing height.Regarding center of pressure stability,there were no significant interactions or main effects of the tDCS intervention on the mean lateral displacement,mean lateral displacement velocity,mean anterior-posterior displacement,or mean anterior-posterior displacement velocity at the center of pressure(P＞0.05).Furthermore,the tDCS intervention had no significant main effects on any of the center of pressure indicators(P＞0.05).In conclusion,tDCS can immediately improve core stability and lower limb joint stability during single-leg landing,making it an effective warm-up technique for improving single-leg landing stability and reducing the risk of lower limb injuries.
RESUMEN
Objective To develop a ground medical rescue platform to facilitate comfortable,safe and efficient medical rescue of astronauts at manned spaceflight landing sites.Methods A ground medical rescue platform for manned spaceflight landing site with vehicle-mounted structure was composed of a high-performance CTM-132 chassis,a rescue shelter made of aerospace aluminum plate and a hydraulic tailboard to facilitate astronauts'entry and exit.There were a variety of devices equipped in the rescue shelter for space medical monitoring and support,medical treatment and communication,and refined design was carried out for the electrical and water circuits and lighting.Results The ground medical rescue platform enabled medical monitoring and support of astronauts after returning to landing sites.Conclusion The ground medical rescue platform with the functions of medical monitoring,support and treatment meets the requirements for astronaut medical rescue at landing sites,and can be used as a supplement to the air medical rescue platform.[Chinese Medical Equipment Journal,2023,44(10):23-27]
RESUMEN
Objective:To review the characteristics and coping strategies of the rescue and landing medical support mission of Shenzhou-14 manned spacecraft.Methods:The characteristics of rescue and landing medical support mission of Shenzhou-14 manned spacecraft was analyzed, and the coping strategies and experience were discussed.Results:(1) The characteristics of rescue and landing medical support mission of Shenzhou-14 manned spacecraft included: long time in space station and high-intensity space missions; high-density space medical support mission in short term; special environmental factors in severe cold night; complex terrain of landing site; and the young medical support team. (2) The main coping strategies of rescue and landing medical support mission of Shenzhou-14 manned spacecraft included: strengthened the organization and leadership and improved the training model; reinforcement learning the medical treatment plan and strengthened the medical rescue skills training; optimized the carrying equipment and added the heat preservation and lighting measures; improved the medical rescue process and perfected the emergency plan; emphasized on the scientific research as important as mission; and strengthened the physical exercise and cold resistance exercise.Conclusions:The characteristics and coping strategies of rescue and landing medical support mission of Shenzhou-14 manned spacecraft are summarized to provide the experience for space medical rescue and offer the support for China's manned space industry.
RESUMEN
OBJECTIVE To provide reference for the subsequent landing of national medical insurance negotiated drugs （referred to as “national negotiated drugs”） at the provincial level. METHODS By reviewing the data publicly released by the official websites of National Healthcare Security Administration and the Healthcare Security Administration of Zhejiang Province， combined with policy documents， the descriptive analysis was conducted on the number of tertiary medical institutions， the actual allocation of national negotiated drugs， the availability rate of national negotiated drugs， the allocation rate of national negotiated drug varieties， and the allocation rate of medical institutions of various cities in Zhejiang province. The Spearman rank correlation test was used to analyze the correlation between the number of types of national negotiated drugs equipped in tertiary medical institutions in Zhejiang province and the per capita disposable income， the number of tertiary medical institutions equipped with national negotiated drugs， and the implementation time of disease diagnosis-related grouping （DRG） of various cities in Zhejiang province. RESULTS As of the first quarter of 2022， 135 tertiary medical institutions in Zhejiang province were equipped with a total of 261 types of national negotiated drugs， accounting for 94.91% of the 2021 edition of the National Negotiated Drugs Catalogue （275 types）. The allocation rates of Goserelin acetate sustained-release implant， Sacubitril valsartan sodium tablets， Alteplase for injection and other varieties were at high level， and the types of national negotiated drugs equipped were highly coincident with the top 10 causes of death with disease of urban and rural residents in Zhejiang province. The tertiary medical institutions in Hangzhou had the most types of national negotiated drugs， with 230 types， while Quzhou had the lowest， with only 34 types； allocation rate of national negotiated drugs in medical institutions of Zhoushan was the highest （100%）， while that of Lishui was the lowest （57.14%）. The types of national negotiated drugs equipped were positively correlated with per capita disposable income in various cities and the number of tertiary medical institutions equipped with national negotiated drugs （P＜0.01）， and there was no significant correlation with the length of implementation of DRG （P＞0.05）. CONCLUSIONS mail：lanyao@mails.tjmu.edu.cn The landing of national negotiated drugs in Zhejiang province is generally good， with a high rate of equipping tertiary medical institutions with national negotiated drugs and a high rate of equipping drug varieties. Therefore， it is recommended that the provincial implementation of national negotiated drugs should be multi-faceted， and policy-making departments should adopt a dual-channel of “unbundling” and “driving” to smooth the drug chain into hospitals. The health insurance sector should improve the “dual channel” management mechanism to share the pressure on hospitals to use drugs. At the same time， it should also improve the multi-level medical security system and raise the level of reimbursement of medical insurance for national negotiated drugs.
RESUMEN
Objective To analyze the differences of von Mises stress distribution in knee cartilage and meniscus in female with generalised joint hypermobility (GJH) and healthy female during drop jump landing. Methods The kinematic and ground reaction force (GRF) characteristics of knee joint in female with GJH and healthy female at the moment of peak vertical GRF (VGRF) during loading phase of drop jump landing were collected. The knee joint reaction force was calculated via inverse dynamics, and the combined force of knee joint along long axis of the femur was applied as the load. Based on three-dimensional (3D) finite element model of a female knee joint, numerical simulations were performed separately during drop jump landing of subjects in two groups, and von Mises stresses and stress distribution of knee cartilage and meniscus were calculated. Results At the moment of peak VGRF during drop jump landing, knee flexion and valgus angles in GJH group and control group showed a statistical significance (P<0. 05). Compared with control group, knee flexion angle decreased and valgus angle increased in GJH group. During drop jump landing, GJH group bore larger stress inside the knee joint, and stress distribution in weight-bearing areas of the medial and lateral tibiofemoral compartments was uneven, while the lateral femoral cartilage lateral condyle, the anterior and middle lateral of lateral tibial cartilage, the anterior angle and body lateral margin of lateral meniscus were stress concentration sites. Conclusions For females with GJH, the stability of knee joint decreases and force lines change in jumping events, due to the increased range of motion of knee joint and relaxation of joint capsule, which increases the risk of cartilage and meniscal injury in lateral knee joint. During jumping sports, females with GJH should especially prevent knee joint injury caused by altered force lines in frontal plane of knee joint.
RESUMEN
Objective To make classification and segment measurement for the cases with tibiofibular and ankle fractures in parachuting landing, and investigate main classification types of parachuting fractures and fracture segments of high risk.Methods A total of 56 fracture cases in parachuting landing were collected, and the tibiofibula and ankle fractures were classified according to AO-OTA or Lauge-Hansen classification standards respectively based on their digital X-ray images. The medium plane between talus and tibia joint planes in ankle joint was defined as the reference plane. The highest and lowest injury points of tibia and fibula were marked respectively, and the fracture segment was defined between the highest and lowest point for statistical analysis.Results For tibiofibular and ankle fracture cases in parachuting landing, fracture at both tibia and fibula accounted for 80.4%. The major classification of tibiofibula fracture was 42-D/5.2 (45.8%) and 42-D/5.1 (16.7%). The major classification for ankle fracture was pronation-external rotation (PER, 59.4%) and supination-external rotation (SER, 37.5%). When tibiofibular and ankle fracture cases in parachuting landing occurred, the fracture segment of the tibia was mainly from 57 to 143 mm above the reference plane and from 6 mm below the reference plane to 24 mm above the reference plane, while the fracture segment of the fibula was 4-45 mm and 74-83 mm above the reference plane. Injury risks of all above segments were higher than 50%.Conclusions For protection of lower limbs in parachuting landing, the fracture at both tibia and fibula should be highly noticed. The ankle motion of PER and SER should be especially restricted in parachuting ankle protection.
RESUMEN
Objective To examine the effects of ankle brace on biomechanics of the lower extremity during landing, so as to provide a theoretic support to choose ankle brace for people with different sports levels. Methods The key words (ankle brace OR ankle braces OR ankle bracing OR ankle support) AND (landing OR land OR jump OR hopped OR hopping) AND (biomechanics OR kinematics OR kinetics OR electromyography OR neuromuscular) in Chinese and English were searched from different electronic databases (CNKI, Web of Science, EBSCO, PubMed and other databases), for a period of Jan. 2000 to Dec. 2020. Cochrane was used to evaluate the quality of eligible studies. For meta analysis, subgroup analysis was used to assess the impact of ankle braces on ankle biomechanics.Results Thirteen studies with a total of 222 participants were included for mata analysis in this study. The semi-rigid ankle brace reduced the peak of ankle inversion by 25.8% compared with the elastic ankle brace (SMD=-0.562, P<0.001). Moreover, the elastic ankle brace reduced ankle plant flexion during landing among athletes (SMD=-3.42, P=-0.021). As for collagiate students, both elastic ankle and semi-rigid ankle decreased the ankle inversion (elastic ankle brace: 35.4%, SMD=-1.000, P=-0.013; semi-rigid ankle brace: 31.11%, SMD=-0.881, P<0.001) and ankle plant flexion (elastic ankle brace:23.30%, SMD=-1.381, P<0.001;semi-rigid ankle brace: 36.33%, SMD=-1.605, P<0.001).Conclusions Both ankle braces can prevent ankle sprain for athletes (basketball, volleyball, running) who experience training more than 5 years. The elastic ankle brace can limit the inversion and plantar flexion, while the semi-rigid ankle brace can merely decrease the ankle inversion. Therefore, athletes are more suitable for the elastic ankle brace. As for collegiate students without training history, both ankle brace can decrease the ankle inversion and plantar flexion. The elastic ankle brace has greater restriction on inversion, while the semi-rigid ankle brace has more restriction on plantar flexion. Therefore, the elastic ankle brace should be utilized if collegiate students have calcaneofibular ligament injury, while the semi-rigid ankle brace is more suitable for collegiate students who have a history of anterior talofibular ligament injury.
RESUMEN
Objective To compare the effects of hip abductor fatigue on postural stability and neuromuscular control in different gender groups during single-leg side-jump landing. Methods Twenty male and twenty female adults were required to execute single-leg side-jump landing before and after hip abductor fatigue protocol. The center of pressure (COP), ground reaction force (GRF), lower extremity kinematics, joint moment, muscle activity were compared. Results For both males and females after fatigue, the maximum displacements and average velocities of COP decreased, and the peak angles of hip abduction and ankle eversion increased, and the peak torques of ankle inversion increased. At 200 ms pre-landing, the activiation of rectus femoris, biceps femoris, tibialis anterior, peroneus longus were lower in male than that in female. At 200 ms post-landing, the activiation of biceps femoris in male was lower than that in female after fatigue. Conclusions The postural stability in frontal plane decreased after hip abductor fatigue. The frontal plane control of hip joint and ankle joint was weakened, which might increase the risk of joint injury. There are differences in postural strategies for different genders, indicating that gender difference in the mechanism of lower limb joint injury is worth of further investigation.
RESUMEN
Objective To analyze the impact of soldiers’ single-leg landing with load carriage on knee joint, and investigate its relationship with muscle strength, so as to provide references for daily load carriage training. Methods A total of 12 soldiers were required to perform single-leg landing from the 30 cm height without load carriage and with 15 kg load carriage,respectively.The kinematic and kinetic parameters were collected using Vicon motion capture system and AMTI force platform. The surface electromyography (sEMG) of anterior and posterior thigh muscles were also collected simultaneously, and the isokinetic strength during knee flexion and extension was tested. Results Compared with landing without load carriage, knee flexion angle and joint reaction force significantly increased during landing with 15 kg load carriage (P0.05). There was a significant negative correlation between peak moment of knee extension and vertical ground reaction force during single-leg landing without load carriage (P0.05). Conclusions Knee flexion angle and joint reaction force significantly increase during single-leg landing with 15 kg load carriage, the activation of anterior and posterior thigh muscles can relieved the ground reaction force during landing, and muscle strength plays some role in preventing landing injury.
RESUMEN
Objective:To discuss the medical support strategy by summarizing the experience of medical support in Dongfeng landing site.Methods:According to the current situation of medical support at Dongfeng landing site and the practice and experience of previous medical support, a retrospective summary study was conducted.Results:The main methods were summarized: (1) formulate a feasible plan; (2) strictly screen skilled personnel; (3) provide reasonable medicinal materials and equipments; (4) complete the modification of the rescue carrier; (5) attach importance to the training of first aid techniques; (6) strengthen political and ideological education; (7) carry out physical fitness training; (8) seriously participate in actual combat training. Three points of experience were put forward: (1) the importance of thinking and action is the premise of completing the task; (2) the cooperation between training and actual combat is the basis for completing the task; (3) equal emphasis on education and management is the bottom line for completing the task.Conclusions:The medical support experience of the Dongfeng landing site is summarized to provide support and experience for the long-term in-orbit operation of China's space station and on-site medical rescue after the landing of the manned spacecraft.
RESUMEN
Objective:Summarize the experience of the medical rescue team at the main landing site of China's manned space mission, analyze the new characteristics of the Shenzhou 12 space station mission, and take corresponding countermeasures and measures to ensure the strong medical rescue guarantee for astronauts.Methods:Search the publications about astronaut medical aid domestic and abroad, summarize the rescue and medical aid experiences from Shenzhou 5 to Shenzhou 11. In consideration of prolonged on-orbit time, Location adjustment of the landing site and the new characteristics of the complex terrain, new targeted strategies were presented.Results:The astronauts flew in orbit for 90 days, and the main landing site and launch site are in the same area. The medical security includes three parts: launch section, running section and return section. Desert rescue model were added. Ten injuries were simulated and each injury first-aid procedure was standardized.Conclusion:After targeted improvement and optimization, the Shenzhou 12 astronauts medical rescue support program ensures the safety of the whole process, all-weather and all-terrain emergency and rear delivery of the astronauts in the new mission environment and complex terrain.
RESUMEN
Objective To study effects of backpack gravity center position on kinetics and kinematics of lower-extremity joints in parachuting landing and evaluate the injuries. Methods Seven participants performed parachuting landing with backpack gravity center on three positions: low-back (position 1), upper-back (position 2) and abdomen (position 3). Results The peak vertical ground reaction force (GRF) with backpack on position 2 was significantly lower than that on position 1. The joint moment on sagittal plane of the hip with backpack on position 2 was significantly higher than that on position 1 and position 3. The joint energy absorption of the hip with backpack on position 2 was significantly higher than that on position 1. The angular displacement of the hip on sagittal plane with backpack on position 2 was significantly higher than that on position 1 and was significantly lower than that on position 3. The angular velocity of the hip on sagittal plane with backpack on position 2 was significantly lower than that on position 3. Conclusions Different positions of backpack gravity center could significantly influence kinetic and kinematic parameters of the hip. Backpack gravity center on upper-back position could decrease the lower-extremity injuries. The results can provide evidences for evaluating backpack gravity center and decreasing injuries in parachuting landing.
RESUMEN
Objective To determine the effect of trunk motion control on knee biomechanics during single-leg landing. Methods Twenty male healthy basketball players were recruited. The kinematics, kinetics parameters and surface electromyogram (EMG) of knee joints under trunk motion control during single-leg landing were studied by using Vicon motion Analysis system, Kistler force platform and Noraxon surface EMG system. Results Compared with natural landing, there were significant differences in flexion angle at initial contact moment, peak flexion angle and peak flexion moment during deeply inspiratory landing and landing with a stick, and a significantly larger flexion angle at initial contact moment, a larger peak flexion angle and smaller peak flexion moment were also found. Compared with natural landing, there was no statistical difference in peak valgus angle and peak valgus moment, as well as EMG activity of hamstrings, quadriceps muscles of the knee during deeply inspiratory landing and landing with a stick. Conclusions Deeply inspiratory landing or landing with a stick reduce the risk of anterior cruciate ligament (ACL) injury, and the results provide the theoretical basis for prevention of ACL injuries in basketball players during landing.
RESUMEN
Abstract Aim: Lower-body non-contact injuries in team sport athletes (TSAs) are associated when absorbing force, during cutting and landing movements due to a lack of eccentric strength and decreased neuromuscular control leading to excessively higher joint forces. Thus, this project aimed to identify if TSAs had different acceleration and deceleration force profiles compared to a control group (non-TSA) when performing drop jumps (DJs). Methods: University TSAs (n = 15) and non-TSAs (n = 10) performed a series of DJs from a 39 cm box onto a force-plate. All data were normalized to the individual's body mass. Between-group differences in ground reaction force (GRF), rate of force development (RFD), and propulsive and breaking impulses were compared via t-tests and standardized differences. Results: TSAs had significantly, and meaningfully greater RFD than the non-TSAs (p < 0.01, Hedges' g (ES) = 1.24, 53%). While not statistically significant, the non-TSA group produced practically larger mean GRFs than TSAs (p = .09, ES = 0.72, 12.1%). No significant or meaningful between-group differences were detected for propulsive impulse (p = 0.08, ES = 0.41, 9.1%), braking impulse (p = 0.85, ES = 0.25, 4.6%), or impulse ratio (p = 0.35, ES = 0.21, 6.7%). Conclusions: This study shows the presence of significant RFD differences during the DJ in TSAs compared to non-TSAs. Furthermore, this investigation also showed there was no difference between TSA and students in GRF and impulse metrics. Implications from these findings suggest that TSAs can produce force rapidly, but deceleration metrics were not different from untrained students.
Asunto(s)
Humanos , Desaceleración , Fuerza Muscular , Aceleración , Deportes de EquipoRESUMEN
Objective To examine the effects of shoe cushioning on impact characteristics, kinematics and dynamics of lower extremities before and after neuromuscular fatigue during drop landing. Methods Fifteen trained male athletes were required to execute three successful trials of drop landing from a 60-cm platform before and after fatigue protocol. The impact force, loading rate, lower extremity kinematics, joint moment, joint stiffness were compared. Results Before fatigue, highly-cushioned shoes reduced the loading rate at heel before fatigue, and the time to peak loading rate of heel was significantly shorter than that of control shoes. After fatigue, highly-cushioned shoes significantly reduced the peak impact force and loading rate at heel, loading rate at forefoot. Meanwhile the time to peak impact force and peak loading rate at heel were significantly longer, and the contact and minimum angle of ankle were significantly greater. No significant changes were found in lower extremity stiffness, peak moment and joint stiffness of ankle. Conclusions In the situation where neuromuscular activity is reduced, highly-cushioned shoes can effectively attenuate the impact, thereby helping to avoid or reduce the potential impact damage after fatigue.
RESUMEN
BACKGROUND@#Inversion ankle sprains are among the most common traumatic injuries for both men and women caused by jumping and landing activities. The ankle is protected by the static and dynamic stabilizers to reduce the incidences of injuries. Furthermore, using a non-elastic closedbasket weave taping technique is one of the common interventions to prevent it. Knowledge about the muscle activity reaction of the dynamic stabilizers upon application of tape is limited with varying results.@*OBJECTIVES@#To determine the effect of non-elastic closed-basket weave ankle taping on the muscle activity of tibialis anterior, peroneus longus, medial, and lateral gastrocnemius on healthy individuals during jump landing on a hard, flat surface.@*METHODS@#This study is a quasi-experimental study using a pre- and post-test design. Peak amplitude muscle activity was assessed and analyzed using surface electromyography (sEMG) after landing from a jump. The pre-test was done by jump landing without tape, after which post-test data was immediately collected after applying the non-elastic closed-basket weave taping. Jump landing was done for three trials for both pre- and post-tests. A paired t-test was used to determine significant differences in pre-post taping.@*RESULTS@#Fifteen healthy participants were included in the study (9 females, 6 males) with a mean age of 21 + 1.03 years old and BMI of 22.74 + 1.63 kg/m2. No significant difference was observed on peak amplitude muscle activity of the tibialis anterior (p= 0.06), medial gastrocnemius (p= 0.32), and lateral gastrocnemius (p= 0.66) after application of tape. However, a significant difference was observed in the peroneus longus after the application of tape (p= 0.05) during jump landing@*CONCLUSION@#Non-elastic closed-basket weave taping decreased the peak amplitude muscle activity of the peroneus longus during jump landing. This research suggests that tape may influence the peroneus longus, and it may or may not be detrimental in reducing the risk of ankle sprains.