Gender differences in onset timing and activation of the muscles of the dominant knee during stair climbing

An electromyographical analysis (EMG) of knee muscle activation patterns and time delays has rarely been discussed in the literature. The purpose of this study was to compare the activation time and EMG amplitude of the dominant vastus medialis and medial hamstring muscles during stair climbing. Fifteen male and 18 female subjects participated in this study. The subjects were asked to ascend and descend 14 steps, five times. There was a significant time delay difference between genders during stair climbing (F = 8.37, p = 0.008). The female subjects demonstrated longer time delays while descending the steps. In addition, the female subjects demonstrated significantly lower normalized EMG amplitude during down stair climbing (F = 5.77, p = 0.025) while the male subjects demonstrated higher normalized EMG amplitude for the vastus medialis muscle while descending the steps. These results suggest that female subjects possess an increased risk factor for knee injuries during down stair climbing due to muscle activation delays with decreased vastus medialis muscle activity.     

Kinetic comparison of older men and women during walk-to-stair descent transition

Stair walking is one of the most challenging tasks for older adults, with women reporting higher incidence of falls. The purpose of this study was to investigate the gender differences in kinetics during stair descent transition. Twenty-eight participants (12 male and 16 female; 68.5 and 69.0 years of mean age, respectively) performed stair descent from level walking in a step-over-step manner at a self-selected speed over a custom-made three-step staircase with embedded force plates. Kinematic and force data were combined using inverse dynamics to generate kinetic data for gender comparison. The top and the first step on the staircase were chosen for analysis. Women showed a higher trail leg peak hip abductor moment (−1.0 N m/kg), lower trail leg peak knee extensor moment and eccentric power (0.74 N m/kg and 3.15 W/kg), and lower peak concentric power at trail leg ankle joint (1.29 W/kg) as compared to men (p < 0.05; −0.82 N m/kg, 0.89 N m/kg, 3.83 W/kg, and 1.78 W/kg, respectively). The lead leg knee eccentric power was also lower in women (p < 0.05). This decreased ability to exert knee control during stair descent transition may predispose women to a higher risk of fall.     

蚧梯式健康宣教结合PDCA循环护理管理对妊娠蠼高血压疾病患者的影响

目的探析阶梯式健康宣教结合PDCA循环护理管理对妊娠期高血压疾病的影响。方法将120例妊娠期高血压疾病孕妇分为两组各60例,观察组予以阶梯式健康宣教结合PDCA循环护理,对照组予以常规护理。对比两组母婴结局、满意度、疾病知晓率及遵医行为。结果观察组剖宫产率显著低于对照组,护理满意度、疾病知晓率及遵医行为率均显著高于对照组,差异具有统计学意义（P〈0．05）。结论阶梯式健康宣教结合PDCA循环护理管理有助于改善母婴结局,提高护理满意度及患者对疾病的认识和遵医行为。     

A new protocol from real joint motion data for wear simulation in total knee arthroplasty: Stair climbing

In its normal lifespan, a knee prosthesis must bear highly demanding loading conditions, going beyond the sole activity of level walking required by ISO standard 14243. We have developed a protocol for in vitro wear simulation of stair climbing on a displacement controlled knee simulator. The flexion/extension angle, intra/extra rotation angle, and antero/posterior translation were obtained in patients by three-dimensional video-fluoroscopy. Axial load data were collected by gait analysis. Kinematics and load data revealed a good consistence across patients, in spite of the different prosthesis size. The protocol was then implemented and tested on a displacement controlled knee wear simulator, showing an accurate reproduction of stair climbing waveforms with a relative error lower than 5%.     

Clinical disability in posterior cruciate ligament deficient patients does not relate to knee laxity,but relates to dynamic knee function during stair descending

We investigated the factors which influence clinical subjective symptoms during activities in Posterior cruciate ligament (PCL) deficient patients by evaluating knee laxity, muscle strength and knee mechanics during level walking, stair ascent and descent. Twenty-two subjects with isolated PCL deficient knees and 20 healthy volunteers were involved. The PCL deficient patients were divided into two subgroups based on previous history of experiencing giving-way during stair descent; a giving-way group (10 subjects) and a nongiving-way group (12 subjects). Giving-way during activities of daily living is a key symptom in isolated PCL deficient patients. No statistically significant differences in the knee laxity, muscle strength and knee mechanics during level walking and were observed between the giving-way group and the nongiving-way group. However, we found significant differences in the knee mechanics during stair ascent and descent between the two groups, and these differences were more remarkable during stair descent. Peak values of knee flexion angle, external knee flexion moment and posterior knee force during early stance phase were significantly lower in the giving-way group than in the nongiving-way group. This study indicated that the symptom of giving-way during stair descent was related to knee mechanics during stair descent, unlike other quantitative evaluations such as KT-2000 or Biodex.     

上楼梯对人工膝关节假体磨损影响的有限元研究

目的通过有限元磨损模型研究上楼梯对衬垫磨损的影响,对完善人工膝关节的磨损评估方法、指导假体设计等具有重要的理论和实际意义。方法基于Archard磨损理论建立人工膝关节衬垫磨损的有限元模型并验证,然后加载正常水平行走(ISO14243标准)和上楼梯的载荷,对比分析上楼梯对衬垫磨损的影响。结果水平行走步态载荷下,模型预测的磨损结果与文献实验报道结果一致,模型具有较好的有效性。上楼梯的体积磨损率为每100万次循环(million cycle,MC)37.10 mm~3,显著高于水平行走步态的体积磨损率(16.94 mm~3/MC),线性磨损也具有类似的结果。上楼梯内侧平台的磨损区域主要集中在后部,与水平行走时内侧平台的磨损主要发生在中部区域有明显不同。结论上楼梯作为高载荷、高屈膝角度的日常运动之一,对人工膝关节衬垫的磨损有较大影响,其磨损率和磨损区域与水平行走有明显差异,在人工膝关节的磨损检测和评估中应该给予适当的重视。     

The role of sensory conflict on stair descent performance in humans

Summary Electromyographic (EMG) activity produced in the triceps surae (TS) and subsequent landing were examined under various visual conditions during stair descent with the following results: The amount of precontact TS EMG was reduced during each visual perturbation. Perturbations corresponded to no knowledge or visualization of stairs (B), no stair visualization during descent (A) and vertical movement of the surround during descent (M). Erroneous visual information was primarily responsible for altered EMG activity. The only known difference between the M data sets was that the surround moved up (U) or down (D) as the subject descended. However, TS EMG characteristics were different under these two conditions. Specific visual information appeared necessary for vision to override the other sensory systems. There was no difference in EMG when the room moved up (U) compared to the room not moving (NM). However, EMG activity was significantly different when the room moved down (D) compared to the room not moving (NM). The relationship between TS EMG activity and subsequent landing appeared related to landing strategy. Although the EMG was reduced during both the B and M test conditions compared to the control, the landing was softer for B and harder for M. The pre-contact EMG is apparently part of a preprogrammed movement pattern which can be modified by sensory information during task execution. Future studies should examine the neuronal mechanisms which provide the visual system access to the center controlling lower limb muscle activity during dynamic movement.Supported in part by Research Grant No. 1 RO1 NS 14133 from the National Institute of Neurological and Communicative Disorders and Stroke, and by the Rehabilitation Engineering Center (REC) Grant No. G008003003 from the National Institute of Handicapped ResearchThese results were presented in part at the Tenth Annual Meeting of the Society for Neuroscience     

Performance of stair negotiation in patients with cerebral palsy and stiff knee gait

BackgroundDue to the limited knee range of motion, achieving adequate foot clearance while walking on level ground constitutes a major problem for patients with cerebral palsy and stiff knee gait. Stair negotiation as an activity of daily life requires a considerably higher knee range of motion than level ground walking, but little is known yet as to whether such patients are able to walk stairs.Research question: The aim of this study was to investigate how patients with a limited knee range of motion negotiate stairs. Do they increase their peak knee flexion and use the same pattern as in walking on level ground? How do the muscles act during stair negotiation?MethodsIn this explorative study, 17 adults with bilateral, spastic cerebral palsy and stiff knee gait and 25 healthy subjects were examined. 3D motion analysis, including electromyography, was performed while walking on level ground, upstairs, and downstairs. A linear mixed model was used for between- and within-group comparisons.ResultsWalking upstairs and downstairs, patients increased their peak knee flexion by around 30° compared to level walking. Thus, increased knee flexion may be seen as the main mechanism for maintaining foot clearance on stairs. An increased pelvic obliquity (elevation) and hip flexion were also found and involved subjects showed a slight increase in rectus femoris activity when walking on stairs compared to level walking within the phases of high knee flexion.SignificanceThis study showed that patients with cerebral palsy and stiff knee gait are able to flex their knees more than would be required for level walking. Hence, the patients are able to adapt their rectus activity to stair walking to some extent. Therefore, further investigations might help to open up new therapeutic options to facilitate level walking and stair negotiation in patients with stiff knee gait.     

Predictors of Physical and Functional Loss in Advanced-Stage Lung Cancer Patients Receiving Platinum Chemotherapy

Introduction

Muscle wasting has detrimental effects, including increased mortality. Identifying patients at risk can guide treatment efforts.