Search results for "force platform"

Force Platform Balance Measures as Predictors of Indoor and Outdoor Falls in Community-Dwelling Women Aged 63-76 Years

2008

Background. Inability to maintain balance while standing increases risk of falls in older people. The present study assessed whether center of pressure (COP) movement measured with force platform technology predicts risk for falls among older people with no manifest deficiency in standing balance. Methods. Participants were 434 community-dwelling women, aged 63-76 years. COP was measured in six stances on a force platform. Following balance tests, participants reported their falls with 12 monthly calendars. Incidence rate ratios (IRR) with 95% confidence intervals (CI) were computed from negative binomial regression models. For the analysis, those with>/=1 fall indoors were coded"indoor fal…

Balance control in aging: improvements in anticipatory postural adjustments and updating of internal models

2015

International audience; Postural stability of older subjects can be estimated during orthostatic equilibrium. However, dynamic equilibrium is also important to investigate risks of fall. It implies different interpretations of measures given by force plates. Same dependant variables (e.g. center of pressure displacement) cannot be interpreted the same ways depending of the type of equilibrium that is investigated. In particular, sways increases during dynamic equilibrium and before movement execution may reflect an improvement of feedforward control.

Determinants of elite-level air rifle shooting performance

2015

This study focused on identifying the most important factors determining performance in elite-level air rifle shooting technique. Forty international- and national-level shooters completed a simulated air rifle shooting competition series. From a total of 13 795 shots in 319 tests, shooting score and 17 aiming point trajectory variables were measured with an optoelectronic device and six postural balance variables were measured with force platform. Principal component analysis revealed six components in the air rifle shooting technique: aiming time, stability of hold, measurement time, cleanness of triggering, aiming accuracy, and timing of triggering. Multiple regression analysis identifie…

2019

This paper describes a single body-mounted sensor that integrates accelerometers, gyroscopes, compasses, barometers, a GPS receiver, and a methodology to process the data for biomechanical studies. The sensor and its data processing system can accurately compute the speed, acceleration, angular velocity, and angular orientation at an output rate of 400 Hz and has the ability to collect large volumes of ecologically-valid data. The system also segments steps and computes metrics for each step. We analyzed the sensitivity of these metrics to changing the start time of the gait cycle. Along with traditional metrics, such as cadence, speed, step length, and vertical oscillation, this system est…

Validation of portable 2D force binding systems for cross-country skiing

2013

The aim of the present study was to design, construct and scientifically validate a two-dimensional force measurement binding system for cross-country skiing. The system consists of two force measurement bindings. One binding was designed for analysing classic skiing (vertical and anterior–posterior [along the ski] force components) and the other one for skate (freestyle) skiing (vertical and medio-lateral [transverse to the ski] force components). Validation was accomplished using a three-step process: (1) accuracy tests for the sensors in two temperatures, (2) sport-specific imitation jump test on standard force plates in a laboratory and (3) comparing the system against force measurement…

Virtual simulation of an osseointegrated trans-humeral prosthesis: A falling scenario

2018

Abstract Introduction Traditional prosthetic solutions expose the amputee to numerous problems that limit his ability to safely perform the normal activities of daily life. In order to eliminate the problems related to the use of the traditional prosthesis with socket, a new technique was developed for fixing the prosthesis to the amputees based on the principle of osseointegration. The aim of this paper is to study and analyze the stress distribution on the interface between a trans-humeral osseointegrated prosthetic implant and the residual bone, identifying the most stressed areas and thus foreseeing possible failure phenomena of the entire prosthetic system and, after, to compare the st…

Postural balance and self-reported functional ability in 75-year-old men and women: a cross-national comparative study.

1997

OBJECTIVE To study postural balance in relation to self-reported functional ability (mobility and ADL) and general physical activity in elderly men and women living in three different Nordic environments. PARTICIPANTS A random sample of 448 men and 556 women from among the 75-year-old residents in Glostrup, Denmark, and Goteborg, Sweden, and all the residents of relevant age (127 men and 261 women) in Jyvaskyla, Finland. MEASUREMENTS Assessment of postural balance with eyes open and closed using a piezoelectric force platform. A structured interview on self-reported functional ability and physical activity. An in-laboratory medical examination. RESULTS In spite of some differences in balanc…

Biomechanical analysis of anticipation of elite and inexperienced goalkeepers to distance shots in handball

2012

AbstractThe objective of this study was to evaluate the anticipation time and kinematic factors in the movement ofgoalkeepers’ center of mass when making a long-distance throw in handball. The sample group was composed of 14goalkeepers and field players. A force platform was used to measure the force of the goalkeepers’ reaction movements, whilethe throwers’ movements were recorded with high-speed cameras. The expert goalkeepers began to move 193 ± 67 ms beforethe ball was released, with a 67% success rate of interception. The inexperienced goalkeepers began their movement 209 ±127 ms with a 24% success rate. The time taken by expert goalkeepers to begin a vertical movement of their CM, rel…

Sensory reweighting in frail aged adults: Are the balance deficiencies mainly compensated by visual or podal dependences?

2021

Abstract Background Postural control is based on the integration of different sensory inputs. The process of scaling the relative importance of these sensory cues (visual, vestibular and proprioceptive) depends on individuals and creates sensory preferences, leading to sensory dependences when one particular source is preponderant. In this context, the literature showed a frequent visual dependence (visual inputs weighting) in aged adults. However, the somaesthetic inputs can also be prioritised in a podal-dependent profile. In the frail aged adults, none study has shown the distribution of these two dependences. Research question Which sensory orientation profile is preferentially adopted …

Variability and Symmetry of Force Platform Variables in Maximum-Speed Running in Young and Older Athletes

2010

Eighteen young (23 ± 4 yr) and 25 older (70 ± 4 yr) male sprinters were examined for ground reaction force (GRF) and temporal-spatial variables. The data were collected during maximum-speed phase, and variability and symmetry indices were calculated from a total of 8 steps. There was little variation (CV < 6%) in vertical and resultant GRF and kinematic variables, while impact loading had high variability (CV: 10–21%). Overall, the pattern of variability was similar in both groups. Yet, a small but significant age-related increase in CV was evident in horizontal GRFs. There was a variable-specific asymmetry between legs but it was not related to leg dominance. No age differences existed …