Associations between ground reaction force waveforms and sprint start performance

2019 ◽  
Vol 14 (5) ◽  
pp. 658-666 ◽  
Author(s):  
Steffi L Colyer ◽  
Philip Graham-Smith ◽  
Aki IT Salo
Keyword(s):  
Reaction Force ◽  
Statistical Parametric Mapping ◽  
Force Production ◽  
Mass Motion ◽  
Ground Reaction Forces ◽  
Centre Of Mass ◽  
Specific Training ◽  
Force Vector ◽  
Reaction Forces ◽  
External Power

Ground reaction forces produced on the blocks determine an athlete’s centre of mass motion during the sprint start, which is crucial to sprint performance. This study aimed to understand how force waveforms are associated with better sprint start performance. Fifty-seven sprinters (from junior to world elite) performed a series of block starts during which the ground reaction forces produced by the legs and arms were separately measured. Statistical parametric mapping (linear regression) revealed specific phases of these waveforms where forces were associated with average horizontal external power. Better performances were achieved by producing higher forces and directing the force vector more horizontally during the initial parts of the block phase (17–34% and 5–37%, respectively). During the mid-push (around the time of rear block exit: ∼54% of the block push), magnitudes of front block force differentiated performers, but orientation did not. Consequently, the ability to sustain high forces during the transition from bilateral to unilateral pushing was a performance-differentiating factor. Better athletes also exhibited a higher ratio of forces on the front block in the latter parts of unilateral pushing (81–92% of the block push), which seemed to allow these athletes to exit the blocks with lower centre of mass projection angles. Training should reflect these kinetic requirements, but also include technique-based aspects to increase both force production and orientation capacities. Specific training focused on enhancing anteroposterior force production during the transition between double- to single-leg propulsion could be beneficial for overall sprint start performance.

scholarly journals Spring-like leg behaviour, musculoskeletal mechanics and control in maximum and submaximum height human hopping

2011 ◽  
Vol 366 (1570) ◽  
pp. 1516-1529 ◽  
Author(s):  
Maarten F. Bobbert ◽  
L. J. Richard Casius
Keyword(s):  
Energy Expenditure ◽  
Muscle Activation ◽  
Mechanical Energy ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Centre Of Mass ◽  
Leg Stiffness ◽  
Reaction Forces ◽  
And Control ◽  
The Relationship

The purpose of this study was to understand how humans regulate their ‘leg stiffness’ in hopping, and to determine whether this regulation is intended to minimize energy expenditure. ‘Leg stiffness’ is the slope of the relationship between ground reaction force and displacement of the centre of mass (CM). Variations in leg stiffness were achieved in six subjects by having them hop at maximum and submaximum heights at a frequency of 1.7 Hz. Kinematics, ground reaction forces and electromyograms were measured. Leg stiffness decreased with hopping height, from 350 N m −1 kg −1 at 26 cm to 150 N m −1 kg −1 at 14 cm. Subjects reduced hopping height primarily by reducing the amplitude of muscle activation. Experimental results were reproduced with a model of the musculoskeletal system comprising four body segments and nine Hill-type muscles, with muscle stimulation STIM( t ) as only input. Correspondence between simulated hops and experimental hops was poor when STIM( t ) was optimized to minimize mechanical energy expenditure, but good when an objective function was used that penalized jerk of CM motion, suggesting that hopping subjects are not minimizing energy expenditure. Instead, we speculated, subjects are using a simple control strategy that results in smooth movements and a decrease in leg stiffness with hopping height.

Catapult start likely improves sprint start performance

2021 ◽  
pp. 174795412110151
Author(s):  
Ryu Nagahara ◽  
Sam Gleadhill
Keyword(s):  
Effect Size ◽  
Force Production ◽  
Technical Training ◽  
Ground Reaction Forces ◽  
Control Effect ◽  
Forward Motion ◽  
Sprint Time ◽  
Reaction Forces ◽  
External Power

Sprint technical training, named the catapult start, is defined as partner assisted pulling of the hip backward at the set position and during block clearance, released by the forward motion of the athlete. This study investigated the characteristics of the catapult start and its influence on the following sprint start performance. Fourteen male sprinters performed a single 15-m control, catapult, and post-catapult sprint starts, during which ground reaction forces (GRFs) were measured using force platforms. All measured GRF variables during the block clearance, except for the impulses and mean forces on the front block and ratio of force for the rear block, were greater in the catapult start than the control (effect size [ES]=0.52–2.09). Waveform analyses revealed that the rear block anteroposterior GRF was greater for the catapult start than the control during the initial, middle and final phases (0 to 20%, 40 to 61% and 95 to 100%) of block clearance, while the rear block ratio of force was greater for the catapult start until 13% of block clearance. The catapult start resulted in greater rear block ratio of force (ES = 0.28), faster 10-m sprint time (ES = 0.31) and greater average horizontal external power during the initial 10-m (ES = 0.25) at the post-catapult trial. The results suggest that the catapult start can be accompanied with greater force production mainly for the rear block regardless of direction during the block clearance, and it can improve post-catapult sprint start performance in terms of the rear block ratio of force and 10-m sprint time.

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 Ground Reaction Forces and Kinematics of Ski Jump Landing Using Wearable Sensors

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2011 ◽  
Author(s):  
Bessone ◽  
Petrat ◽  
Schwirtz
Keyword(s):  
Wearable Sensors ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Inertial Motion ◽  
Jump Landing ◽  
The Past ◽  
Landing Biomechanics ◽  
Reaction Forces ◽  
The Hill ◽  
Kinematics And Kinetics

In the past, technological issues limited research focused on ski jump landing. Today, thanks to the development of wearable sensors, it is possible to analyze the biomechanics of athletes without interfering with their movements. The aims of this study were twofold. Firstly, the quantification of the kinetic magnitude during landing is performed using wireless force insoles while 22 athletes jumped during summer training on the hill. In the second part, the insoles were combined with inertial motion units (IMUs) to determine the possible correlation between kinematics and kinetics during landing. The maximal normal ground reaction force (GRFmax) ranged between 1.1 and 5.3 body weight per foot independently when landing using the telemark or parallel leg technique. The GRFmax and impulse were correlated with flying time (p < 0.001). The hip flexions/extensions and the knee and hip rotations of the telemark front leg correlated with GRFmax (r = 0.689, p = 0.040; r = −0.670, p = 0.048; r = 0.820, p = 0.007; respectively). The force insoles and their combination with IMUs resulted in promising setups to analyze landing biomechanics and to provide in-field feedback to the athletes, being quick to place and light, without limiting movement.

Ground reaction force and hoof deceleration patterns on two different surfaces at the trot

2006 ◽  
Vol 3 (4) ◽  
pp. 209-216 ◽  
Author(s):  
Pia Gustås ◽  
Christopher Johnston ◽  
Stig Drevemo
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Force Plate ◽  
Ground Surface ◽  
Ground Reaction Forces ◽  
Triaxial Accelerometer ◽  
Loading Rates ◽  
Sand Surface ◽  
Reaction Forces ◽  
Force Data

AbstractThe objective of the present study was to compare the hoof deceleration and ground reaction forces following impact on two different surfaces. Seven unshod Standardbreds were trotted by hand at 3.0–5.7 m s− 1 over a force plate covered by either of the two surfaces, sandpaper or a 1 cm layer of sand. Impact deceleration data were recorded from one triaxial accelerometer mounted on the fore- and hind hooves, respectively. Ground reaction force data were obtained synchronously from a force plate, sampled at 4.8 kHz. The differences between the two surfaces were studied by analysing representative deceleration and force variables for individual horses. The maximum horizontal peak deceleration and the loading rates of the vertical and the horizontal forces were significantly higher on sandpaper compared with the sand surface (P < 0.001). In addition, the initial vertical deceleration was significantly higher on sandpaper in the forelimb (P < 0.001). In conclusion, it was shown that the different qualities of the ground surface result in differences in the hoof-braking pattern, which may be of great importance for the strength of the distal horse limb also at slow speeds.

Correlation between Ground Reaction Force and Tibial Acceleration in Vertical Jumping

2007 ◽  
Vol 23 (3) ◽  
pp. 180-189 ◽  
Author(s):  
Niell G. Elvin ◽  
Alex A. Elvin ◽  
Steven P. Arnoczky
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Force Plate ◽  
Coefficient Of Determination ◽  
Ground Reaction Forces ◽  
Accelerometer Data ◽  
Jump Height ◽  
Vertical Jumping ◽  
Average Coefficient ◽  
Reaction Forces

Modern electronics allow for the unobtrusive measurement of accelerations outside the laboratory using wireless sensor nodes. The ability to accurately measure joint accelerations under unrestricted conditions, and to correlate them with jump height and landing force, could provide important data to better understand joint mechanics subject to real-life conditions. This study investigates the correlation between peak vertical ground reaction forces, as measured by a force plate, and tibial axial accelerations during free vertical jumping. The jump heights calculated from force-plate data and accelerometer measurements are also compared. For six male subjects participating in this study, the average coefficient of determination between peak ground reaction force and peak tibial axial acceleration is found to be 0.81. The coefficient of determination between jump height calculated using force plate and accelerometer data is 0.88. Data show that the landing forces could be as high as 8 body weights of the jumper. The measured peak tibial accelerations ranged up to 42 g. Jump heights calculated from force plate and accelerometer sensors data differed by less than 2.5 cm. It is found that both impact accelerations and landing forces are only weakly correlated with jump height (the average coefficient of determination is 0.12). This study shows that unobtrusive accelerometers can be used to determine the ground reaction forces experienced in a jump landing. Whereas the device also permitted an accurate determination of jump height, there was no correlation between peak ground reaction force and jump height.

Some Gait Characteristics of Below-Knee Amputees and Their Reflection on the Ground Reaction Forces

1986 ◽  
Vol 15 (1) ◽  
pp. 27-34 ◽  
Author(s):  
R Seliktar ◽  
J Mizrahi
Keyword(s):  
Reaction Force ◽  
Kinetic Studies ◽  
Human Locomotion ◽  
Rate Of Change ◽  
Ground Reaction Forces ◽  
Test Results ◽  
Small Perturbations ◽  
Gait Characteristics ◽  
Reaction Forces ◽  
Force Characteristics

Human locomotion studies employing cinematography and force plates have been conducted during the last five decades with the goal of producing a clinically acceptable gait evaluation technique. The bulk of information contained in the kinetic studies was the major obstacle in achieving this goal. Our aim in this work was to explore the possibility of representing some locomotor abnormalities solely by their reflection on the ground reaction force characteristics. As a first stage towards the establishment of these relationships, the gait characteristics of below-knee amputees were examined. One hundred and thirty ground force test results as obtained on twenty three below-knee amputees were analysed. Different variables such as time durations of the various phases, peak forces, impulses, rate of change of the forces, and others, were examined. The conclusions suggest that some of these variables are suitable for evaluation of gait and some, such as small perturbations superimposed on the curve, may serve as indicators of specific malfunction of the prosthetic system.

Dynamic-joint-strength-based two-dimensional symmetric maximum weight-lifting simulation: Model development and validation

2020 ◽  
Vol 234 (7) ◽  
pp. 660-673
Author(s):  
Ritwik Rakshit ◽  
Yujiang Xiang ◽  
James Yang
Keyword(s):  
Joint Strength ◽  
Reaction Force ◽  
Weight Lifting ◽  
Ground Reaction Forces ◽  
Two Dimensional ◽  
Joint Angles ◽  
Maximum Weight ◽  
Strength Based ◽  
Optimization Formulation ◽  
Reaction Forces

This article presents an optimization formulation and experimental validation of a dynamic-joint-strength-based two-dimensional symmetric maximum weight-lifting simulation. Dynamic joint strength (the net moment capacity as a function of joint angle and angular velocity), as presented in the literature, is adopted in the optimization formulation to predict the symmetric maximum lifting weight and corresponding motion. Nineteen participants were recruited to perform a maximum-weight-box-lifting task in the laboratory, and kinetic and kinematic data including motion and ground reaction forces were collected using a motion capture system and force plates, respectively. For each individual, the predicted spine, shoulder, elbow, hip, knee, and ankle joint angles, as well as vertical and horizontal ground reaction force and box weight, were compared with the experimental data. Both root-mean-square error and Pearson’s correlation coefficient ( r) were used for the validation. The results show that the proposed two-dimensional optimization-based motion prediction formulation is able to accurately predict all joint angles, box weights, and vertical ground reaction forces, but not horizontal ground reaction forces.

scholarly journals Force Pattern and Acceleration Waveform Repeatability of Amateur Runners

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 136
Author(s):  
Ophelie Lariviere ◽  
Thomas Provot ◽  
Laura Valdes-Tamayo ◽  
Maxime Bourgain ◽  
Delphine Chadefaux
Keyword(s):  
Stance Phase ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Multiple Correlation ◽  
Risk Of Injury ◽  
Straight Line ◽  
Reaction Forces ◽  
Tibial Acceleration ◽  
Acceleration Signals ◽  
Study Performance

Although accelerometers’ responses during running are not perfectly understood, they are widely used to study performance and the risk of injury. To outline the typical tibial acceleration pattern during running, this study aims to investigate the repeatability of acceleration signals with respect to the ground reaction force waveforms. Ten amateur runners were asked to perform ten trials along a straight line. One participant was asked to perform this protocol over ten sessions. Tibial accelerations and ground reaction forces were measured during the stance phase. The coefficient of multiple correlation R was computed to study the intra- and inter-test and subject repeatability of accelerometric and force waveforms. A good (R>0.8) intra- and inter-test repeatability was observed for all measured signals. Similar results were observed for intra-subject repeatability. A good inter-subject repeatability was observed only for the longitudinal acceleration and vertical and antero-posterior forces. Typical accelerometric signatures were outlined for each case studied.

Sign in / Sign up

Export Citation Format

Share Document