1st Joint ESMAC-GCMAS Meeting - Análise de Marcha

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phase on the force platform was stimulated. Data collection continued until at least 6 good trials had been collected with and without the stimulus. The means of the stimulated and unstimulated trials were compared. The difference showed the effect of the FES perturbation and was interpreted as the dynamic action of the muscle. For example where the stimulation caused greater flexion the action was defined as ‘flexing’. Results The results for the knee and ankle kinematics during second rocker are shown [Figure 1]. This was the period in which difference between the muscle actions was most prominent. 4 2 0 -2 -4 -6 -2 -4 -6 Knee Flexing 0 10 20 30 40 50 60 Subject 1 Subject 2 Knee Extending Subject 3 Subject 4 Subject 5 Ankle Dorsiflexing Subject 1 Subject 2 Subject 3 Subject 4 Subject 5 4 2 0 Stimulation 0 10 20 30 40 50 60 Subject 1 Subject 2 Ankle Plantarflexing Subject 3 Subject 4 Subject 5 Stimulation Gastrocnemius Soleus Figure 1. Action of gastrocnemius and soleus during second rocker. A point is marked on the graph when the mean of 5 stimulated traces differed from the mean of 5 interspersed unstimulated traces by at least 2 standard deviations. Discussion The responses of individual subjects to the stimulation varied, however a clear pattern emerges. During second rocker gastrocnemius and soleus have antagonistic actions. The action of gastrocnemius as an ankle dorsiflexor and knee flexor is certainly surprising. These results confirm predictions from previous computer model simulations, in that they highlight clear differences in action between two components of the triceps surae [1] [2]. The action at the knee is the same as that reported by Neptune et al. (2001). The next step is to perform subjectspecific IAA simulations based on the data collected and compare the effects of FES perturbations with the IAA predictions in each case. It will be interesting to see whether the IAA results confirm the patterns shown above and reflect the same inter-subject variability. References [1] Hof AL & Otten E, (2005), Gait Posture, 22:182-188. [2] Neptune RR, Kautz SA & Zajac FE, (2001), J Biomech, 34:1387-1398 [3] Chen G, (2006), Gait Posture, 23:37-44 - 151 - % Gait Cycle Subject 1 Subject 2 Subject 3 Subject 4 Subject 5
O-42 DYNAMIC SIMULATIONS OF SLOW, FREE, AND FAST WALKING: HOW DO MUSCLES MODULATE FORWARD PROGRESSION? Liu, May, M.S. 1 , Jonkers, Ilse, Ph.D. 2 , Arnold, Allison, Ph.D. 1 , Schwartz, Michael, Ph.D. 3 , Thelen, Darryl, Ph.D. 4 , Anderson, Frank, Ph.D. 1 , Delp, Scott, Ph.D. 1 1 Depts. of Mechanical Engineering & Bioengineering, Stanford University, Stanford, USA 2 Faculty of Kinesiology & Rehabilitation Sciences, KULeuven, Leuven, Belgium 3 Center for Gait & Motion Analysis, Gillette Children’s Specialty Healthcare, St. Paul, USA 4 Department of Mechanical Engineering, University of Wisconsin, Madison, USA Summary/conclusions Forward progression during walking is modulated by the same muscles, regardless of speed. Propulsion from hip flexors and plantarflexors increases with speed, as does the braking actions of knee extensors. Introduction Unimpaired children can increase or decrease walking speed with ease, a task that is often difficult for children with musculoskeletal disorders. However, the mechanisms by which unimpaired individuals modulate walking speed are unclear. Prior EMG studies have shown that muscle activity increases with walking speed (e.g., [1]), but how this altered activity influences walking dynamics is unknown. Muscle-actuated simulations have provided insight into how muscles generate propulsion during walking at a typical free speed (e.g., [2-3]). Using subject-specific dynamic simulations of walking, we tested the hypothesis that faster walking speed is achieved by increasing the propulsive actions of the same muscles that modulate progression at a normal walking speed. Statement of clinical significance A common therapeutic goal for patients with impairments is to improve walking speed. Understanding how muscles generate forward progression at slow and fast speeds in unimpaired children may aid the development of more effective treatments to improve walking speed in patients with gait abnormalities. Methods Three-dimensional kinematics and ground reaction forces for an unimpaired child (11 y.o) were collected at self-selected slow, free, and fast overground walking speeds. We scaled a musculoskeletal model (21 degrees of freedom, 92 muscle-tendon actuators) to the subject’s anthropometry and used computed muscle control [4] to generate forward dynamic walking simulations at each speed. Computed kinematics and muscle excitations were consistent with experimental kinematics and EMG. Each simulation consisted of a half-gait cycle, beginning at the onset of double support (loading response of left limb, preswing of right limb). Muscleinduced fore-aft accelerations of the body mass center were computed using a perturbation analysis [3]. Accelerations from stance-limb muscles were averaged over four phases: loading response (double support, negative fore-aft GRF), early single-limb support (negative fore-aft GRF), late single-limb support (positive fore-aft GRF), and preswing (double support, positive fore-aft GRF). In each phase, muscles that generated ≥ 80% of the total braking or propulsive induced acceleration were identified. - 152 -
Page 1 and 2:
O-01 KNEE EXTENSION AT TERMINAL SWI
Page 3 and 4:
O-02 THE MODIFIED TARDIEU IN STANDI
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O-03 COORDINATION BETWEEN PELVIS, T
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O-04 CAN GAIT ANALYSIS GUIDE MANAGE
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O-05 DISTAL FEMORAL EXTENTSION OSTE
Page 11 and 12:
O-06 THE EFFECT OF SHOES ON GAIT IN
Page 13 and 14:
O-07 CORRELATIONS BETWEEN CLINICAL
Page 15 and 16:
O-08 DOUBLE CALIBRATION VS GLOBAL O
Page 17 and 18:
O-09 THE SYMMETRICAL AXIS OF ROTATI
Page 19 and 20:
O-10 FEASIBILITY OF A NEW -JOINT CO
Page 21 and 22:
O-11 A SINGLE GAIT CYCLE AS MEASURE
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O-12 IMPROVED TRACKING OF HIP ROTAT
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O-13 PROTOCOL CHANGES CAN IMPROVE T
Page 27 and 28:
O-14 ALTERNATIVE METHODS FOR MEASUR
Page 29 and 30:
O-15 OVERLAY PROJECTION OF 3D GAIT
Page 31 and 32: O-16 RELATIONSHIP BETWEEN THE ANTHR
Page 33 and 34: O-17 COMPARING THE RELIABILITY OF V
Page 35 and 36: O-18 3D HIP AND PELVIC GAIT PATTERN
Page 37 and 38: O-19 RELIABILITY AND VALIDITY OF AN
Page 39 and 40: O-20 HOW ACCURATE IS THE ESTIMATION
Page 41 and 42: O-21 IMPACT OF WHEELCHAIR PROPULSIO
Page 43 and 44: O-22 TOWARDS A NEW PROTOCOL FOR MOT
Page 45 and 46: O-23 KINEMATIC ANALYSIS OF UPPER LI
Page 47 and 48: O-24 KINEMATIC UPPER LIMB ANALYSIS
Page 49 and 50: O-25 3D KINEMATICS OF UPPER EXTREMI
Page 51 and 52: O-26 CLINICALLY SIGNIFICANT SHOULDE
Page 53 and 54: O-27 OBJECTIVE IDENTIFCATION OF GAI
Page 55 and 56: - 110 - O-28 NORMALCY GAIT INDEX AN
Page 57 and 58: O-29 GILLETTE GAIT INDEX IS CONSIST
Page 59 and 60: O-30 GAITABASE: NEW APPROACH TO CLI
Page 61 and 62: O-31 A MODIFIED GAIT CLASSIFICATION
Page 63 and 64: O-32 QUANTIFICATION OF KINEMATIC ME
Page 65 and 66: O-33 EXTRINSIC AND INTRINSIC VARIAT
Page 67 and 68: O-34 PAIRED OUTCOME ASSESSMENT OF A
Page 69 and 70: O-35 ENERGY EXPENDITURE DURING OVER
Page 71 and 72: O-36 HIGH FAILURE RATES WHEN AVOIDI
Page 73 and 74: O-37 SUBJECT SPECIFIC HIP GEOMETRY
Page 75 and 76: O-38 BIOMECHANICAL AND METABOLIC PE
Page 77 and 78: O-39 BIOMECHANICS OF GAIT IN CHARCO
Page 79 and 80: O-40 SAGITTAL PLANE LOWER EXTREMITY
Page 81: O-41 AN EXPLORATION OF THE FUNCTION
Page 85 and 86: O-43 AUTOMATIC IDENTIFICATION OF MU
Page 87 and 88: O-44 DYNAMIC MEASUREMENT OF GASTROC
Page 89 and 90: O-45 ASSESSING THE REGULATORY ACTIV
Page 91 and 92: O-46 ABNORMAL EMG-ACTIVITY IN PATHO
Page 93 and 94: O-47 AVERAGED EMG PROFILES IN RUNNI
Page 95 and 96: O-48 TRACKING DYNAMIC FOOT PRESSURE
Page 97 and 98: O-49 THE INFLUENCE OF FOOTWEAR SOLE
Page 99 and 100: O-50 GAIT ANALYSIS IN CHILDREN TREA
Page 101 and 102: O-51 A COMPARISON OF METHODS FOR US
Page 103 and 104: O-52 BIOMECHANICAL OPTIMIZATION OF
Page 105 and 106: O-53 EFFECT OF SENSORY-THRESHOLD EL
Page 107 and 108: O-54 THE IMPACT OF SINGLE EVENT MUL
Page 109 and 110: O-55 COMPREHENSIVE GAIT ANALYSIS OU
Page 111 and 112: O-56 THE EFFECT OF INCLUDING S2 ROO
Page 113 and 114: O-57 DYNAMIC FUNCTION AFTER ANTERIO
Page 115 and 116: O-58 RECOVERY OF MUSCLE STRENGTH FO
Page 117 and 118: O-59 AUDITORY-PACED WALKING FOLLOWI
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1st Joint ESMAC-GCMAS Meeting - Análise de Marcha

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