Effect of Speed, Step Frequency and Age on the Bouncing Step

2017 ◽  
pp. 203-222
Author(s):  
Giovanni Cavagna
Keyword(s):  
Step Frequency

scholarly journals Ground Penetrating Radar Survey of the Floor of the Accademia Gallery (Florence, Italy)

2021 ◽  
Vol 13 (7) ◽  
pp. 1273
Author(s):  
Lapo Miccinesi ◽  
Alessandra Beni ◽  
Silvia Monchetti ◽  
Michele Betti ◽  
Claudio Borri ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Air Conditioning ◽  
Underground Structure ◽  
Step Frequency ◽  
Ground Floor ◽  
The Public ◽  
Ground Penetrating

This paper reports the results of a ground penetrating radar (GPR) survey of the ground-floor of Academia Gallery (Florence, Italy) where the Michelangelo’s David is exhibited to the public. The equipment used was a step-frequency GPR operating in the 100 MHz-1 GHz band, named ORFEUS. The survey covered an area of 13 m × 7.3 m, and the scans were performed along two orthogonal directions. Acquisitions in the same direction were separated by 0.25 m from each other. The GPR was able to confirm the underground structure, as it can be deducted by planimetry and historical documentation. In particular, the radar clearly detected the air-conditioning ducts under the floor and an approximately circular foundation below the basement of the statue.

scholarly journals Is Skeletal Muscle Dysfunction a Limiting Factor of Exercise Functional Capacity in Patients with Sickle Cell Disease?

2021 ◽  
Vol 10 (11) ◽  
pp. 2250
Author(s):  
Etienne Gouraud ◽  
Philippe Connes ◽  
Alexandra Gauthier-Vasserot ◽  
Camille Faes ◽  
Salima Merazga ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sickle Cell Disease ◽  
Muscle Fatigue ◽  
Sickle Cell ◽  
Functional Capacity ◽  
Muscle Dysfunction ◽  
Electromyographic Activity ◽  
Cell Disease ◽  
Step Frequency ◽  
Hemoglobin C

Patients with sickle cell disease (SCD) have reduced functional capacity due to anemia and cardio–respiratory abnormalities. Recent studies also suggest the presence of muscle dysfunction. However, the interaction between exercise capacity and muscle function is currently unknown in SCD. The aim of this study was to explore how muscle dysfunction may explain the reduced functional capacity. Nineteen African healthy subjects (AA), and 24 sickle cell anemia (SS) and 18 sickle cell hemoglobin C (SC) patients were recruited. Maximal isometric torque (Tmax) was measured before and after a self-paced 6-min walk test (6-MWT). Electromyographic activity of the Vastus Lateralis was recorded. The 6-MWT distance was reduced in SS (p < 0.05) and SC (p < 0.01) patients compared to AA subjects. However, Tmax and root mean square value were not modified by the 6-MWT, showing no skeletal muscle fatigue in all groups. In a multiple linear regression model, genotype, step frequency and hematocrit were independent predictors of the 6-MWT distance in SCD patients. Our results suggest that the 6-MWT performance might be primarily explained by anemia and the self-paced step frequency in SCD patients attempting to limit metabolic cost and fatigue, which could explain the absence of muscle fatigue.

scholarly journals The Effect of Different Turn Speeds on Whole-Body Coordination in Younger and Older Healthy Adults

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2827
Author(s):  
Fuengfa Khobkhun ◽  
Mark Hollands ◽  
Jim Richards
Keyword(s):  
Older Adults ◽  
Repeated Measures ◽  
Mixed Model ◽  
Healthy Adults ◽  
Whole Body ◽  
Onset Latency ◽  
Step Frequency ◽  
Step Size ◽  
Younger Adults ◽  
Mixed Model Analysis

Difficulty in turning is prevalent in older adults and results in postural instability and risk of falling. Despite this, the mechanisms of turning problems have yet to be fully determined, and it is unclear if different speeds directly result in altered posture and turning characteristics. The aim of this study was to identify the effects of turning speeds on whole-body coordination and to explore if these can be used to help inform fall prevention programs in older adults. Forty-two participants (21 healthy older adults and 21 younger adults) completed standing turns on level ground. Inertial Measurement Units (XSENS) were used to measure turning kinematics and stepping characteristics. Participants were randomly tasked to turn 180° at one of three speeds; fast, moderate, or slow to the left and right. Two factors mixed model analysis of variance (MM ANOVA) with post hoc pairwise comparisons were performed to assess the two groups and three turning speeds. Significant interaction effects (p < 0.05) were seen in; reorientation onset latency of head, pelvis, and feet, peak segmental angular separation, and stepping characteristics (step frequency and step size), which all changed with increasing turn speed. Repeated measures ANOVA revealed the main effects of speeds within the older adults group on those variables as well as the younger adults group. Our results suggest that turning speeds result in altered whole-body coordination and stepping behavior in older adults, which use the same temporospatial sequence as younger adults. However, some characteristics differ significantly, e.g., onset latency of segments, peak head velocity, step frequency, and step size. Therefore, the assessment of turning speeds elucidates the exact temporospatial differences between older and younger healthy adults and may help to determine some of the issues that the older population face during turning, and ultimately the altered whole-body coordination, which lead to falls.

scholarly journals A Doppler Range Compensation for Step-Frequency Continuous-Wave Radar for Detecting Small UAV

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1331
Author(s):  
Massimiliano Pieraccini ◽  
Lapo Miccinesi ◽  
Neda Rojhani
Keyword(s):  
Short Range ◽  
Continuous Wave ◽  
Range Shift ◽  
Specific Method ◽  
Step Frequency ◽  
Wave Radar ◽  
Small Uav ◽  
The Doppler Effect ◽  
Set Up ◽  
Free Falling

Step-frequency continuous-wave (SFCW) modulation can have a role in the detection of small unmanned aerial vehicles (UAV) at short range (less than 1–2 km). In this paper, the theory of SFCW range detection is reviewed, and a specific method for correcting the possible range shift due to the Doppler effect is devised. The proposed method was tested in a controlled experimental set-up, where a free-falling target (i.e., a corner reflector) was correctly detected by an SFCW radar. This method was finally applied in field for short-range detection of a small UAV.

Development of a Small-sized Ku-band Step-frequency SAR

2021 ◽  
Author(s):  
Yury M. Meleshin ◽  
Anastasiya A. Zatonskaya ◽  
Zhanna V. Merkulova ◽  
Alexey A. Biryuk ◽  
Marat S. Khasanov
Keyword(s):  
Step Frequency ◽  
Ku Band

Application of step-frequency radars in medicine

2014 ◽  
Author(s):  
L. Anishchenko ◽  
M. Alekhin ◽  
A. Tataraidze ◽  
S. Ivashov ◽  
A. Bugaev ◽  
...  
Keyword(s):  
Step Frequency

scholarly journals A Biomechanical Re-Examination of Physical Activity Measurement with Accelerometers

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3399 ◽  
Author(s):  
Jonatan Fridolfsson ◽  
Mats Börjesson ◽  
Daniel Arvidsson
Keyword(s):  
Physical Activity ◽  
Motion Capture ◽  
Group Differences ◽  
Band Pass Filter ◽  
Accelerometer Data ◽  
Age Group ◽  
Frequency Filtering ◽  
Frequency Filter ◽  
Step Frequency ◽  
Activity Intensity

ActiGraph is the most common accelerometer in physical activity research, but it has measurement errors due to restrictive frequency filtering. This study investigated biomechanically how different frequency filtering of accelerometer data affects assessment of activity intensity and age-group differences when measuring physical activity. Data from accelerometer at the hip and motion capture system was recorded during treadmill walking and running from 30 subjects in three different age groups: 10, 15, and >20 years old. Acceleration data was processed to ActiGraph counts with original band-pass filter at 1.66 Hz, to counts with wider filter at either 4 or 10 Hz, and to unfiltered acceleration according to “Euclidian norm minus one” (ENMO). Internal and external power, step frequency, and vertical displacement of center of mass (VD) were estimated from the motion capture data. Widening the frequency filter improved the relationship between higher locomotion speed and counts. It also removed age-group differences and decreased within-group variation. While ActiGraph counts were almost exclusively explained by VD, the counts from the 10 Hz filter were explained by VD and step frequency to an equal degree. In conclusion, a wider frequency filter improves assessment of physical activity intensity by more accurately capturing individual gait patterns.

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