Fatigue increases ankle sprain risk in badminton players: A biomechanical study     

Alexis Herbaut  Julien Delannoy 《Journal of sports sciences》2020,38(13):1560-1565

ABSTRACT

Ankle sprains are the most common injury in regular badminton players and usually occur at the end of a match or training. The purpose of the present study was to examine the influence of fatigue produced by badminton practice on the lower limb biomechanics of badminton players. It was hypothesized that fatigue induces ankle kinematic and lower leg muscle activity changes which may increase the risk of ankle sprain. Ankle kinematics, ankle kinetics and muscles activities of 17 regular badminton players were recorded during lateral jumps before and after an intense badminton practice session. Post-fatigue, ankle inversion at foot strike and peak ankle inversion increased (+2.6°, p = 0.003 and +2.5°, p = 0.005, respectively). EMG pre-activation within 100 ms before foot landing significantly decreased after fatigue for soleus (?23.4%, p = 0.031), gastrocnemius lateralis (?12.2%, p = 0.035), gastrocnemius medialis (?23.3%, p = 0.047) and peroneus brevis (?17.4%, p = 0.036). These results demonstrate impaired biomechanics of badminton players when fatigue increases, which may cause a greater risk of experiencing an ankle sprain injury.  相似文献   

Depressive Symptoms and Violence Exposure: Contributors to Repeat Pregnancies Among Adolescents     

Cheryl A. Anderson  Lisa Pierce 《The Journal of perinatal education》2015,24(4):225-238

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植物生长调节剂在作物生产中的安全使用   总被引：5，自引：0，他引：5  

王小兰 《甘肃广播电视大学学报》2005,15(3):1-4

植物生长调节剂已广泛应用于农作物生产中，能有效改善作物生长状况，提高产品产量和品质，但使用不当也会造成严重的药害。在实际生产中要注意安全使用植物生长调节剂，根据作物品种和使用目标，来选择植物生长调节剂的类型，严格控制浓度及施用方法、时间和次数，从而充分发挥植物生长调节剂的效果。  相似文献   

The influence of heterogeneous exposure and pre-deliberation queries on pretrial publicity effects     

Jon Bruschke  Andrew Gonis III  Sarah A. Hill  Pam Fiber-Ostrow  William Loges 《Communication monographs》2016,83(4):521-534

Prior research on pretrial publicity has produced mixed results and a roughly equal number of studies show an effect, show no effect, or show mixed results. We explored the effects of (a) homogenous vs. heterogeneous exposure (whether deliberating jurors were all exposed to the same publicity or not) and (b) pre-deliberation queries as potential contributors to mixed results. We found an effect for positive but not negative publicity on conviction rates but not evidence ratings. Exposure heterogeneity appears to explain these differences and pre-deliberation queries did appear to play some role in the obtained outcomes. Overall these findings do not replicate a robust publicity effect and future research should consider how homogeneous exposure and pre-deliberation opinion queries influence results.  相似文献   

业余条件下的丝网印刷     

黄问贵  许建平 《九江职业技术学院学报》2004,(4):16-17

直接感光丝网漏印法的技术流程介绍  相似文献   

First-rib stress fracture in two adolescent swimmers: a case report     

Sara Low  Michael Kern 《Journal of sports sciences》2016,34(13):1266-1270

First-rib stress fractures have been described in adolescent athletes in various sports, with only one prior case report of first-rib stress fractures in an adolescent female swimmer. There is a need for research on the cause, management, and prevention of these injuries as they lead to significant morbidity and critical time away from sport for these aspiring athletes. We aimed to describe first-rib stress fractures as a potential cause for non-specific atraumatic chronic shoulder pain in adolescent swimmers and to discuss the different presentations, unique risk factors, treatment, and potential injury prevention strategies of such fractures. We discussed two such cases which were successfully treated with activity modification with restriction of all overhead activity, gradually progressive physical therapy and a return to swimming protocol. First-rib stress fractures can vary in presentation and should be in the differential diagnosis in adolescent swimmers with chronic shoulder pain. These injuries can be successfully managed with rest from overhead activities and physical therapy. Gradual return to competitive swimming can be achieved even with non-union of a first-rib stress fracture. Emphasis on balanced strength training in different muscle groups and proper swimming technique is essential to prevent these injuries.  相似文献   

Validation of the Microsoft Kinect® camera system for measurement of lower extremity jump landing and squatting kinematics     

Moataz Eltoukhy  Adam Kelly  Chang-Young Kim  Hyung-Pil Jun  Richard Campbell 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(1):89-102

Cost effective, quantifiable assessment of lower extremity movement represents potential improvement over standard tools for evaluation of injury risk. Ten healthy participants completed three trials of a drop jump, overhead squat, and single leg squat task. Peak hip and knee kinematics were assessed using an 8 camera BTS Smart 7000DX motion analysis system and the Microsoft Kinect® camera system. The agreement and consistency between both uncorrected and correct Kinect kinematic variables and the BTS camera system were assessed using interclass correlations coefficients. Peak sagittal plane kinematics measured using the Microsoft Kinect® camera system explained a significant amount of variance [Range_hip = 43.5–62.8%; Range_knee = 67.5–89.6%] in peak kinematics measured using the BTS camera system. Across tasks, peak knee flexion angle and peak hip flexion were found to be consistent and in agreement when the Microsoft Kinect® camera system was directly compared to the BTS camera system but these values were improved following application of a corrective factor. The Microsoft Kinect® may not be an appropriate surrogate for traditional motion analysis technology, but it may have potential applications as a real-time feedback tool in pathological or high injury risk populations.  相似文献   

Ankle and knee kinetics between strike patterns at common training speeds in competitive male runners     

Daniel Kuhman  Daniel Melcher 《European Journal of Sport Science》2016,16(4):433-440

The purpose of this study was to investigate the interaction of foot strike and common speeds on sagittal plane ankle and knee joint kinetics in competitive rear foot strike (RFS) runners when running with a RFS pattern and an imposed forefoot strike (FFS) pattern. Sixteen competitive habitual male RFS runners ran at two different speeds (i.e. 8 and 6?min?mile^?1) using their habitual RFS and an imposed FFS pattern. A repeated measures analysis of variance was used to assess a potential interaction between strike pattern and speed for selected ground reaction force (GRF) variables and, sagittal plane ankle and knee kinematic and kinetic variables. No foot strike and speed interaction was observed for any of the kinetic variables. Habitual RFS yielded a greater loading rate of the vertical GRF, peak ankle dorsiflexor moment, peak knee extensor moment, peak knee eccentric extensor power, peak dorsiflexion and sagittal plane knee range of motion compared to imposed FFS. Imposed FFS yielded greater maximum vertical GRF, peak ankle plantarflexor moment, peak ankle eccentric plantarflexor power and sagittal plane ankle ROM compared to habitual RFS. Consistent with previous literature, imposed FFS in habitual RFS reduces eccentric knee extensor and ankle dorsiflexor involvement but produce greater eccentric ankle plantarflexor action compared to RFS. These acute differences between strike patterns were independent of running speeds equivalent to typical easy and hard training runs in competitive male runners. Current findings along with previous literature suggest differences in lower extremity kinetics between habitual RFS and imposed FFS running are consistent among a variety of runner populations.  相似文献   

Effect of gender on trunk and pelvis control during lateral movements with perturbed landing     

Elmar Weltin  Albert Gollhofer  Guillaume Mornieux 《European Journal of Sport Science》2016,16(2):182-189

In lateral reactive movements, core stability may influence knee and hip joint kinematics and kinetics. Insufficient core stabilisation is discussed as a major risk factor for anterior cruciate ligament (ACL) injuries. Due to the higher probability of ACL injuries in women, this study concentrates on how gender influences trunk, pelvis and leg kinematics during lateral reactive jumps (LRJs). Perturbations were investigated in 12 men and 12 women performing LRJs under three different landing conditions: a movable landing platform was programmed to slide, resist or counteract upon landing. Potential group effects on three-dimensional trunk, pelvic, hip and knee kinematics were analysed for initial contact (IC) and the time of peak pelvic medial tilt (PPT). Regardless of landing conditions, the joint excursions in the entire lower limb joints were gender-specific. Women exhibited higher trunk left axial rotation at PPT (women: 4.0 ± 7.5°, men: ?3.1 ± 8.2°; p = 0.011) and higher hip external rotation at both IC and PPT (p < 0.01). But women demonstrated higher knee abduction compared to men. Men demonstrated more medial pelvic tilt at IC and especially PPT (men: –5.8 ± 4.9°, women: 0.3 ± 6.3°; p = 0.015). Strategies for maintaining trunk, pelvis and lower limb alignment during lateral reactive movements were gender-specific; the trunk and hip rotations displayed by the women were associated with the higher knee abduction amplitudes and therefore might reflect a movement strategy which is associated with higher injury risk. However, training interventions are needed to fully understand how gender-specific core stability strategies are related to performance and knee injury.  相似文献   

Mitigating the Effects of Poverty and Crime: the Long-Term Effects of an Early Intervention Programme for Children who were Developmentally Delayed and Prenatally Exposed to Cocaine     

Mary Anne Ullery  Antonio Gonzalez  Lynne Katz 《International Journal of Disability, Development & Education》2016,63(4):403-418

This study explores the long-term impact on participation in the Linda Ray Intervention Program (LRIP) for children (n = 54) who were developmentally delayed and prenatally exposed to cocaine. By identifying a group of programme graduates from a high crime/high poverty neighbourhood in Miami-Dade County using ArcGIS 10.2 software, a quasi-experimental design was used to compare children living in this area who participated in the centre-based modality (5 h a day; 5 days a week) to children living in this area who participated in the home-based modality (3 h per week) on their Florida Comprehensive Assessment Test (FCAT) reading and math scale scores in public school. The children who participated in the centre-based modality reported stronger outcomes in both math and reading FCAT scale scores at the p < .05 level and also out-performed their school-age peers on both math and reading FCAT scores at the p < .05 level.  相似文献