scholarly journals The Effects of Opposition and Gender on Knee Kinematics and Ground Reaction Force During Landing From Volleyball Block Jumps

2010 ◽  
Vol 81 (4) ◽  
pp. 384-391 ◽  
Author(s):  
Gerwyn Hughes ◽  
James Watkins ◽  
Nick Owen
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Knee Kinematics ◽  
And Gender

scholarly journals Limb-dominance and gender differences in the ground reaction force during single-leg lateral jump-landings

2018 ◽  
Vol 30 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Junya Aizawa ◽  
Kenji Hirohata ◽  
Shunsuke Ohji ◽  
Takehiro Ohmi ◽  
Kazuyoshi Yagishita
Keyword(s):  
Gender Differences ◽  
Ground Reaction Force ◽  
Reaction Force ◽  
And Gender ◽  
Limb Dominance ◽  
Jump Landings

scholarly journals Computed dynography, a method for evaluation of gait pattern in treated cases of congenital talipes equino varus

2020 ◽  
Vol 6 (3) ◽  
pp. 611
Author(s):  
Akshay Jain ◽  
Adhir Jain ◽  
Ravi Kant Jain ◽  
Prateek Pathak
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Gait Pattern ◽  
Vertical Ground Reaction Force ◽  
Age And Gender ◽  
Double Support ◽  
Gait Parameters ◽  
Vertical Ground ◽  
Congenital Talipes ◽  
And Gender

<p class="abstract"><strong>Background:</strong> Club foot is characterized by inversion, adduction and equinus. Currently, evaluation of children treated for congenital talipes equino varus (CTEV) includes clinical and radiological examination as well as assessment of function. However, none of the methods is ideal. There should<strong> </strong>be objective methods for better evaluation of function in treated CTEV. Gait analysis is the emerging method in objectively assessing the functional outcome. The aim of the study was to compare the selected measures from vertical ground reaction force variables and gait parameters of treated CTEV children with plantigrade feet, to healthy age and gender matched control group.</p><p class="abstract"><strong>Methods:</strong> We took 31 children with treated CTEV with mean age 8.21 years<strong> </strong>and compared with 31 age and gender matched controls. The patients were initially treated under a standard protocol. Gait cycle properties, step time parameters and vertical ground reaction force variables were recorded and comparison of unilateral and bilateral cases of treated CTEV was done with that of controls.<strong></strong></p><p class="abstract"><strong>Results:</strong> Data showed that despite good clinical results and overall function, residual intoeing, lateral foot walking, mild foot drop, weak plantar flexor power, possible residual inversion deformity of the foot, increased frequency and decreased duration of cycle and asymmetry in gait were the main characteristics of gait of children with treated CTEV. In unilateral cases single and double support times were decreased and in bilateral CTEV double support times are increased.</p><p class="abstract"><strong>Conclusions:</strong> The study confirms that in clubfoot patients who underwent full treatment, gait parameters do not reach normal levels. Gait analysis can be used to quantify gait pattern characteristics and is helpful in evaluation and further development of treatment of patients.</p>

scholarly journals Running ground reaction forces across footwear conditions are predicted from the motion of two body mass components

2019 ◽  
Vol 126 (5) ◽  
pp. 1315-1325 ◽  
Author(s):  
Andrew B. Udofa ◽  
Kenneth P. Clark ◽  
Laurence J. Ryan ◽  
Peter G. Weyand
Keyword(s):  
Ground Reaction Force ◽  
Lower Limb ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Vertical Ground Reaction Force ◽  
Time Patterns ◽  
Foot Strike ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Force Time

Although running shoes alter foot-ground reaction forces, particularly during impact, how they do so is incompletely understood. Here, we hypothesized that footwear effects on running ground reaction force-time patterns can be accurately predicted from the motion of two components of the body’s mass (mb): the contacting lower-limb (m1 = 0.08mb) and the remainder (m2 = 0.92mb). Simultaneous motion and vertical ground reaction force-time data were acquired at 1,000 Hz from eight uninstructed subjects running on a force-instrumented treadmill at 4.0 and 7.0 m/s under four footwear conditions: barefoot, minimal sole, thin sole, and thick sole. Vertical ground reaction force-time patterns were generated from the two-mass model using body mass and footfall-specific measures of contact time, aerial time, and lower-limb impact deceleration. Model force-time patterns generated using the empirical inputs acquired for each footfall matched the measured patterns closely across the four footwear conditions at both protocol speeds ( r2 = 0.96 ± 0.004; root mean squared error  = 0.17 ± 0.01 body-weight units; n = 275 total footfalls). Foot landing angles (θF) were inversely related to footwear thickness; more positive or plantar-flexed landing angles coincided with longer-impact durations and force-time patterns lacking distinct rising-edge force peaks. Our results support three conclusions: 1) running ground reaction force-time patterns across footwear conditions can be accurately predicted using our two-mass, two-impulse model, 2) impact forces, regardless of foot strike mechanics, can be accurately quantified from lower-limb motion and a fixed anatomical mass (0.08mb), and 3) runners maintain similar loading rates (ΔFvertical/Δtime) across footwear conditions by altering foot strike angle to regulate the duration of impact. NEW & NOTEWORTHY Here, we validate a two-mass, two-impulse model of running vertical ground reaction forces across four footwear thickness conditions (barefoot, minimal, thin, thick). Our model allows the impact portion of the impulse to be extracted from measured total ground reaction force-time patterns using motion data from the ankle. The gait adjustments observed across footwear conditions revealed that runners maintained similar loading rates across footwear conditions by altering foot strike angles to regulate the duration of impact.

scholarly journals Small changes in ball position at address cause a chain effect in golf swing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sung Eun Kim ◽  
Jangyun Lee ◽  
Sae Yong Lee ◽  
Hae-Dong Lee ◽  
Jae Kun Shim ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Statistical Parametric Mapping ◽  
Golf Swing ◽  
Whole Body ◽  
Centre Of Mass ◽  
Body Segment ◽  
A Chain ◽  
Professional Golfers ◽  
The Right

AbstractThe purpose of this study was to investigate how the ball position along the mediolateral (M-L) direction of a golfer causes a chain effect in the ground reaction force, body segment and joint angles, and whole-body centre of mass during the golf swing. Twenty professional golfers were asked to complete five straight shots for each 5 different ball positions along M-L: 4.27 cm (ball diameter), 2.14 cm (ball radius), 0 cm (reference position at preferred ball position), – 2.14 cm, and – 4.27 cm, while their ground reaction force and body segment motions were captured. The dependant variables were calculated at 14 swing events from address to impact, and the differences between the ball positions were evaluated using Statistical Parametric Mapping. The left-sided ball positions at address showed a greater weight distribution on the left foot with a more open shoulder angle compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. These trends disappeared during the backswing and reappeared during the downswing. The whole-body centre of mass was also located towards the target for the left-sided ball positions throughout the golf swing compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. We have concluded that initial ball position at address can cause a series of chain effects throughout the golf swing.

scholarly journals Injury prevention in Super-G alpine ski racing through course design

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Gilgien ◽  
Philip Crivelli ◽  
Josef Kröll ◽  
Live S. Luteberget ◽  
Erich Müller ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Course Design ◽  
Reaction Force ◽  
Global Navigation Satellite Systems ◽  
World Cup ◽  
Satellite Systems ◽  
Turn Radius ◽  
Energy Dissipated ◽  
Global Navigation Satellite ◽  
High Level

AbstractIn Super-G alpine ski racing mean speed is nearly as high as in Downhill. Hence, the energy dissipated in typical impact accidents is similar. However, unlike Downhill, on Super-G courses no training runs are performed. Accordingly, speed control through course design is a challenging but important task to ensure safety in Super-G. In four male World Cup alpine Super-G races, terrain shape, course setting and the mechanics of a high-level athlete skiing the course were measured with differential global navigation satellite systems (dGNSS). The effects of course setting on skier mechanics were analysed using a linear mixed effects model. To reduce speed by 0.5 m/s throughout a turn, the gate offset needs to be increased by + 51%. This change simultaneously leads to a decrease in minimal turn radius (− 19%), an increase in impulse (+ 27%) and an increase in maximal ground reaction force (+ 6%). In contrast, the same reduction in speed can also be achieved by a − 13% change in vertical gate distance, which also leads to a small reduction in minimal turn radius (− 4%) impulse (− 2%), and no change in maximal ground reaction force; i.e. fewer adverse side effects in terms of safety. It appears that shortening the vertical gate distance is a better and safer way to reduce speed in Super-G than increasing the gate offset.

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