Wearing transfemoral prosthesis is the only way to complete daily physical activity for amputees. Motion pattern recognition is important for the control of prosthesis, especially in the recognizing swing phase and stance phase. In this paper, it is reported that surface electromyography (sEMG) signal is used in swing and stance phase recognition. sEMG signal of related muscles was sampled by Infiniti of a Canadian company. The sEMG signal was then filtered by weighted filtering window and analyzed by height permitted window. The starting time of stance phase and swing phase is determined through analyzing special muscles. The sEMG signal of rectus femoris was used in stance phase recognition and sEMG signal of tibialis anterior is used in swing phase recognition. In a certain tolerating range, the double windows theory, including weighted filtering window and height permitted window, can reach a high accuracy rate. Through experiments, the real walking consciousness of the people was reflected by sEMG signal of related muscles. Using related muscles to recognize swing and stance phase is reachable. The theory used in this paper is useful for analyzing sEMG signal and actual prosthesis control.
Artificial Limbs ; Electromyography ; Humans ; Leg ; Muscle, Skeletal ; physiology ; Walking ; physiology

DLUT4060 piezoelectric multi-component force platforms and DVM8820 three-dimensional infrared image capture system were used to test the sit-to-walk (STW) movements of 11 healthy elderly (72. 6 +/- 12. 2 years old) and 11 healthy young (19. 7 +/-1. 3 years old) individuals. Firstly, we studied the effects of seat-heights on the ground reaction forces, the velocity of the center of mass, and action time duration. Then we discussed the movement strategies and falling risks of the persons in the two age groups respectively. Finally, we decided the best seat height for the two age groups. It was found that the best seat heights for both the two age groups were 100% popliteal height. This height may make the subject get the greatest biomechanical advantages and the lowest falling risks. The popliteal height must be concerned when designing and fixing up the public activity area facilities and daily life of the elderly. To some extent, it can reduce the falling risk of the elderly.
Accidental Falls ; prevention & control ; Aged ; Aged, 80 and over ; Ankle Joint ; physiology ; Buttocks ; physiology ; Hip Joint ; physiology ; Humans ; Interior Design and Furnishings ; Knee Joint ; physiology ; Leg ; anatomy & histology ; physiology ; Male ; Middle Aged ; Movement ; physiology ; Posture ; Weight-Bearing ; physiology ; Young Adult

Dynamic loads at knee joint of amputee are fundamental for rehabilitation of knee injury and prosthesis design. In this paper, a 3-D model for calculation of dynamic load at knee joint of trans-tibial amputee was developed. Gait analysis was done on three terrains including normal level walking, upstairs and downstairs. Dynamic loads at knee joint were calculated during one gait cycle. The results show that gait patterns and dynamic loads at knee joint were different among these three terrains. Although the general waveforms were about the same, the motion range of knee joint, ground reaction forces and loads at knee joint when walking upstairs or downstairs were larger than those in a normal level walking. The quantitative findings provide the theoretical basis of gait analysis and prosthesis design for trans-tibial amputee.
Amputation Stumps ; physiopathology ; Artificial Limbs ; Biomechanical Phenomena ; Gait ; physiology ; Humans ; Knee Joint ; physiopathology ; Leg ; physiopathology ; surgery ; Prosthesis Design ; Stress, Mechanical ; Tibia ; physiopathology ; surgery ; Walking ; physiology ; Weight-Bearing ; physiology

OBJECTIVETo evaluate the hemodynamic response to passive leg raising (PLR) indicates fluid responsiveness in patients with septic shock.

METHODSTwenty patients with septic shock, considered for fluid challenge (FC), were enrolled in the study from June 2009 to May 2010. Hemodynamic changes were determined by pulse-contour derived cardiac index at baseline, before and after PLR, return to baseline for 10 min, before and after fluid challenge (250 ml saline for 10 min). An increase of SV after fluid challenge (FC-ΔSV) ≥ 10% were defined responders.

RESULTSTwenty patients with septic shock were included in the study. PLR and fluid challenge were performed 46 instances, among which 15 instances were defined as response group. SV and pulse pressure induced by PLR (PLR-ΔSV and PLR-ΔPP) were increased significantly in response group [(76 ± 19) ml vs. (65 ± 18) ml, (73 ± 20) mmHg vs. (62 ± 20) mmHg (1 mmHg = 0.133 kPa), P < 0.05], while in nonresponse group there were no significant change. PLR-ΔSV and PLR-ΔPP were correlated with FC-ΔSV (r = 0.51, P = 0.001; r = 0.45, P = 0.006), central venous pressure (CVP) were unrelated with FC-ΔSV. Area under curve (AUC) for PLR-ΔSV, PLR-ΔPP and stroke volume variation (SVV) were 0.846, 0.791 and 0.708. PLR-ΔSV ≥ 12.5% predicted fluid responsiveness with sensitivity of 80% and specificity of 93.5%. PLR-ΔPP ≥ 9.5% predicted fluid responsiveness with sensitivity of 73.3% and specificity of 83.9%.

CONCLUSIONSPLR-ΔSV and PLR-ΔPP can predict fluid responsiveness in patients with septic shock. PLR-ΔSV and PLR-ΔPP have a greater ability in predicting volume responsiveness than CVP and SVV.

Adult ; Aged ; Aged, 80 and over ; Female ; Hemodynamics ; physiology ; Humans ; Leg ; Male ; Middle Aged ; Posture ; Sensitivity and Specificity ; Shock, Septic ; physiopathology

Venous hemodynamic changes after the surgery of primary varicose veins were evaluated. (Materials and methods) We retrospectively analyzed 1, 211 patients (1, 407 limbs) who underwent surgery for primary varicose veins from 1994 to 2002. The venous hemodynamics were evaluated using air- plethysmography (APG) preoperatively and one month postoperatively in the viewpoints of ambulatory venous pressure (AVP), venous volume (VV), venous filling index (VFI), and ejection fraction (EF). (Results) The surgical modalities included 958 cases of greater saphenous vein high ligation (GSV HL) and stripping with varicosectomy (VS), 222 cases of short saphenous vein (SSV) HL and VS, 143 cases of external banding valvuloplasty of GSV and VS, and 44 cases using VNUS (R) and VS. The reduction rate of VV was 20.9 +/- 14.1% in the GSV stripping group, 12.0 +/-14.7% in the GSV valvuloplasty group, 18.3 +/-16.1% in the VNUS (R) group, and 20.6 +/-15.9% in the SSV group. The reduction rate of VFI was 63.6 +/-20.7% in the GSV stripping group, 38.8 +/-40.9% in the GSV valvuloplasty group, 60.1 +/-23.9% in the VNUS (R) group, and 37.6 +/-30.2% in the SSV group. The increasing rate of EF was 25.0 +/-28.2% in the GSV stripping group, 21.0 +/-30.0% in the GSV valvuloplasty group, 29.4 +/-31.9% in the VNUS (R) group, and 30.0 +/-36.5% in the SSV group. The reduction rate of AVP was 25.4 +/-32.2% in the GSV stripping group, -6.1 +/-58.1% in the GSV valvuloplasty group, 28.4 +/-38.5% in the VNUS (R) group, and 14.1 +/-49.0% in the SSV group. All of the patients showed improvements in venous hemodynamics by showing a decrease in VV, VFI, AVP, and an increase in EF. However, there was no difference in the change of venous hemodynamics according to the type of surgery.
Adult ; Female ; Humans ; Leg/*blood supply ; Male ; Middle Aged ; Plethysmography ; Postoperative Complications ; Regional Blood Flow/*physiology ; Retrospective Studies ; Saphenous Vein/physiology/surgery ; Varicose Veins/*physiopathology/*surgery

As there are a number of ankle arteries and some of them can not be blocked completely under higher pressure from the external inflate cuff, we can not accurately identify the starting point of the pulse wave, so the errors of lower limb systolic blood pressure measurement take place and affect the accuracy of ankle-brachial index in diagnosing vascular disease. In this paper, we constructed delay vectors from the data we already collected from lower limb pulse wave and formed an embedding matrix; thus solving the problem of inadequate sensor dimensions. We extracted a single arterial pulse wave through the blind signal separation on the basis of embedding matrix, and we identified the lower limb systolic blood pressure corresponding to the starting point. Simulation and clinical experiments show the method can be used to separate the wave signals of ankle artery which contains information of systolic blood pressure. It improves the accuracy of lower limb systolic blood pressure measurement and hence provides accurate data for the clinical diagnosis of arterial disease.
Algorithms ; Ankle ; blood supply ; Blood Pressure ; Blood Pressure Determination ; methods ; Brachial Artery ; physiology ; Humans ; Leg ; blood supply ; Pulsatile Flow ; physiology ; Signal Processing, Computer-Assisted

Biomechanical Phenomena ; Child ; Exercise ; physiology ; Female ; Humans ; Leg ; Muscle, Skeletal ; injuries ; physiology ; Peripheral Nervous System Diseases ; Sciatic Neuropathy ; diagnosis ; etiology ; Thigh

The increase in the proportion of elderly people in the population is one of the most remarkable sociodemographic phenomena of the twenty-first century. The number of patients with diabetes is also increasing worldwide with this demographic change. Given these facts, consideration of the problems the general elderly population is facing in the management of diabetes is essential. In this review article, we focus on sarcopenia, which is the decrease in lower extremity muscle mass and muscle strength accompanying aging, describe the relationship between sarcopenia and diabetes, and highlight the specific factors through which diabetes contributes to loss of muscle strength. The quantitative methods for evaluating lower extremity muscle strength will also be described. These methods hold the key to assessing the effectiveness of exercise therapy and optimizing the assessment of the degree of autonomy in the activities of daily living. Exercise is one of the basic treatments for type 2 diabetes and may also prevent and improve sarcopenia. This review discusses the aspects common to the two health conditions and elucidates the effectiveness and necessity of exercise as a preventive measure against diabetes among the elderly.
Aged ; Aged, 80 and over ; Diabetes Mellitus, Type 2 ; physiopathology ; prevention & control ; Exercise Therapy ; Female ; Humans ; Leg ; physiopathology ; Male ; Muscle Strength ; physiology ; Muscle, Skeletal ; physiology ; Sarcopenia ; physiopathology ; prevention & control

OBJECTIVETo explore the changes in lower limb deep vein diameters, blood flow velocity and blood biochemistry in full-term pregnant women for early diagnosis and treatment of prothrombotic state.

METHODSOne hundred and twenty-eight full-term pregnant women at high risk of thrombosis (Group A), 61 healthy full-term pregnant women (Group B), and 42 healthy non-pregnant women (Group C) underwent high-resolution color Doppler ultrasound (CDU) for examining the deep veins of the lower limbs. The hematological indexes such as D-D, PLT, HGB, HCT, TT, APTT, PT, and FbgC were also observed in these 3 groups.

RESULTSCompared to Group B, the women in group A showed significantly increased diameters of the common femoral veins (CFV) and left superficial femoral vein (SFV), HCT and DD, but with significantly decreased peak blood flow in the bilateral popliteal veins (POPV) (P<0.01) and increased left POPV diameter (P=0.034). Compared to those in group C, the diameters of the bilateral CFVs, SFVs, POPV, and posterior tibial veins (PTVs) were significantly increased, but the peak blood flow in the bilateral CFVs and POPVs were significantly reduced in groups A and B; the PLT, HGB, HCT, DD, TT, APTT, PT, and FbgC also showed significant changes in groups A and B (P<0.01).

CONCLUSIONThe full-term pregnant women are at higher risk of prothrombotic state than non-pregnant women, and the full-term pregnant women with the high risk factors for thrombosis are more likely to have prothrombotic state than healthy full-term pregnant women. CDU examination of the lower limb deep veins can be of value in the diagnosis of prothrombotic state.

Adult ; Anthropometry ; Blood Flow Velocity ; Female ; Femoral Vein ; anatomy & histology ; diagnostic imaging ; physiology ; Humans ; Leg ; blood supply ; diagnostic imaging ; Popliteal Vein ; anatomy & histology ; diagnostic imaging ; physiology ; Pregnancy ; physiology ; Ultrasonography

The corticospinal tract (CST) is the most important motor pathway in the human brain. Detailed knowledge of CST somatotopy is important in terms of rehabilitative management and invasive procedures for patients with brain injuries. In this study, I conducted a review of nine previous studies of the somatotopical location and arrangement at the brainstem in the human brain. The results of this review indicated that the hand and leg somatotopies of the CST are arranged medio-laterally in the mid to lateral portion of the cerebral peduncle, ventromedial-dorsolaterally in the pontine basis, and medio-laterally in the medullary pyramid. However, few diffusion tensor imaging (DTI) studies have been conducted on this topic, and only nine have been reported: midbrain (2 studies), pons (4 studies), and medulla (1 study). Therefore, further DTI studies should be conducted in order to expand the literature on this topic. In particular, research on midbrain and medulla should be encouraged.
Brain Stem/*anatomy & histology ; Diffusion Tensor Imaging ; Hand/innervation ; Humans ; Leg/innervation ; Medulla Oblongata/anatomy & histology ; Pons/anatomy & histology ; Pyramidal Tracts/*anatomy & histology/physiology ; Tegmentum Mesencephali/anatomy & histology