Sylvia Õunpuu

Bio: Sylvia Õunpuu is an academic researcher from Boston Children's Hospital. The author has contributed to research in topics: Gait analysis & Ankle. The author has an hindex of 34, co-authored 71 publications receiving 7195 citations. Previous affiliations of Sylvia Õunpuu include University of Connecticut Health Center & University of Waterloo.

Step Length Reductions in Advanced Age: The Role of Ankle and Hip Kinetics

Abstract: BACKGROUND Aging is associated with a reduction in gait velocity, which is due to a shortened step length. This study investigated the relationship between joint kinetics and step length. METHODS Three-dimensional gait kinematics and kinetics were measured during usual pace gait in 26 older subjects (average age 79) and in 32 young subjects (average age 26). Gait measures were obtained at maximal velocity in five older subjects. Lower extremity strength was measured in the older subjects on an isokinetic dynamometer. RESULTS Older persons had a 10% shorter step length during usual gait, when corrected for leg length (.65 +/- .07, .74 +/- .04/leg length, respectively, p < .001). Older persons had reduced ankle plantarflexion during late stance (13 +/- 5 degrees, 17 +/- 5 degrees, p = .02) and lower ankle plantarflexor power (2.9 +/- 0.9 W kg-1, 3.5 +/- 0.9 W kg-1, respectively, p = .007). Ankle strength was associated with plantarflexor power developed during late stance (r = .49, p < .001). When gait kinetics were corrected for step length, the older subjects developed 16% greater hip flexor power during late stance than younger subjects (estimate of effect: .15 W kg-1, p = .002). Older subjects were unable to increase ankle plantarflexor power at maximal pace, but increased hip flexor power 72% (1.1 +/- 0.3 W kg-1 to 1.9 +/- 1.0 W kg-1, p = .02). CONCLUSIONS Older subjects had lower ankle plantarflexor power during the late stance phase of gait and appeared to compensate for reductions in plantarflexor power by increasing hip flexor power. Appropriate training of ankle plantarflexor muscles may be important in maintaining step length in advanced age.

Natural progression of gait in children with cerebral palsy.

Abstract: Twenty-eight children with cerebral palsy had two gait analyses an average of 4.4 years apart with no surgical intervention between the tests. The effects of growth and age were examined using three-dimensional kinematics, temporal and stride parameters, and clinical examination measures. Kinematic changes showed decreases in hip, knee, and ankle sagittal plane ranges of motion (ROM), peak hip flexion in swing, and peak knee flexion over time. Temporal and stride parameters showed declines in timing of toe off, cadence, and walking velocity. Clinical measures showed declines in hip abduction ROM (knees flexed and extended), popliteal angle, and sagittal plane ankle ROM (knees flexed and extended). Overall results showed that gait function in these individuals with cerebral palsy decreased longitudinally with respect to temporal/stride measures, passive ROM, and kinematic parameters compared with a group of individuals who had had orthopaedic intervention.

Three-dimensional lower extremity joint kinetics in normal pediatric gait.

Abstract: Gait analysis is becoming a more integral part of the decision-making process in treatment of children with neuromuscular problems. A normal reference, however, must be available for comparison when one makes decisions. We wished to develop a normal pediatric database for joint kinematics and kinetics which could then be used as a reference for clinical gait analysis. Thirty-one normal children underwent a complete gait analysis including calculations of three-dimensional joint kinematics and kinetics. The pediatric data were similar to that of normal adults.

OpenSim: Open-Source Software to Create and Analyze Dynamic Simulations of Movement

Abstract: Dynamic simulations of movement allow one to study neuromuscular coordination, analyze athletic performance, and estimate internal loading of the musculoskeletal system. Simulations can also be used to identify the sources of pathological movement and establish a scientific basis for treatment planning. We have developed a freely available, open-source software system (OpenSim) that lets users develop models of musculoskeletal structures and create dynamic simulations of a wide variety of movements. We are using this system to simulate the dynamics of individuals with pathological gait and to explore the biomechanical effects of treatments. OpenSim provides a platform on which the biomechanics community can build a library of simulations that can be exchanged, tested, analyzed, and improved through a multi-institutional collaboration. Developing software that enables a concerted effort from many investigators poses technical and sociological challenges. Meeting those challenges will accelerate the discovery of principles that govern movement control and improve treatments for individuals with movement pathologies.

Gait analysis using wearable sensors.

Abstract: Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications.