scholarly journals Flèche versus Lunge as the Optimal Footwork Technique in Fencing

2019 ◽  
Vol 16 (13) ◽  
pp. 2315 ◽  
Author(s):  
Zbigniew Borysiuk ◽  
Natalia Markowska ◽  
Mariusz Konieczny ◽  
Krzysztof Kręcisz ◽  
Monika Błaszczyszyn ◽  
...  
Keyword(s):  
Reaction Time ◽  
Movement Time ◽  
Medial Gastrocnemius ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Muscular Tension ◽  
Explosive Force ◽  
Reaction Forces ◽  
Gastrocnemius Muscles ◽  
Sensorimotor Responses

The objective of the study reported in this paper involved identifying the fencing attack (flèche versus lunge) that provides greater effectiveness in a real competition. Two hypotheses are presented in the study. The first hypothesis involves the greater effectiveness of the flèche with regard to bioelectric muscular tension, and the second hypothesis involves the reduction of movement time of the flèche. Therefore, analyses were conducted by the application of EMG (electromyography) signal, ground reaction forces, and parameters representing sensorimotor responses (RT—reaction time and MT—movement time). This study included six world-leading female épée fencers (mean age: 24.6 ± 6.2 years). Throughout the procedure, the subjects performed flèche and lunge touches at the command of the coach based on visual stimuli. The experimental results indicated the greater effectiveness of the flèche compared with the lunge with regard to increases in EMG values (p = 0.027) in the lateral and medial gastrocnemius muscles and decreases in the duration of the movement phase (p = 0.049) and vertical force of the rear leg (p = 0.028). In conclusion, higher levels of EMG and ground reaction forces were generated during the flèche compared with the lunge, which promotes an improvement in the explosive force and contributes to a reduction in the movement phase of the entire offensive action.

scholarly journals Metabolic cost of generating horizontal forces during human running

1999 ◽  
Vol 86 (5) ◽  
pp. 1657-1662 ◽  
Author(s):  
Young-Hui Chang ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Cost ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Order Of Magnitude ◽  
Reaction Forces ◽  
The Cost ◽  
Support Body Weight ◽  
Human Running

Previous studies have suggested that generating vertical force on the ground to support body weight (BWt) is the major determinant of the metabolic cost of running. Because horizontal forces exerted on the ground are often an order of magnitude smaller than vertical forces, some have reasoned that they have negligible cost. Using applied horizontal forces (AHF; negative is impeding, positive is aiding) equal to −6, −3, 0, +3, +6, +9, +12, and +15% of BWt, we estimated the cost of generating horizontal forces while subjects were running at 3.3 m/s. We measured rates of oxygen consumption (V˙o 2) for eight subjects. We then used a force-measuring treadmill to measure ground reaction forces from another eight subjects. With an AHF of −6% BWt,V˙o 2 increased 30% compared with normal running, presumably because of the extra work involved. With an AHF of +15% BWt, the subjects exerted ∼70% less propulsive impulse and exhibited a 33% reduction inV˙o 2. Our data suggest that generating horizontal propulsive forces constitutes more than one-third of the total metabolic cost of normal running.

scholarly journals The Effect of First-Step Techniques from the Staggered Stance in American Football

2017 ◽  
Vol 01 (02) ◽  
pp. E69-E73
Author(s):  
Nikolas Knudsen ◽  
Thomas Andersen
Keyword(s):  
Reaction Time ◽  
Random Order ◽  
American Football ◽  
Football Players ◽  
Ground Reaction Forces ◽  
Time Analysis ◽  
Sprint Time ◽  
Reaction Forces ◽  
Force Profiles ◽  
Time Linear

AbstractThe purpose of this study was to evaluate 3 different starting techniques from the staggered stance with regards to sprint time, reaction time, linear impulse and power. 11 male amateur American football players volunteered to participate in a testing session consisting of twelve 5 m sprints, 4 in each technique (normal (NORM), backwards false step (BFS) and forwards false step (FFS)) in random order. Sprint starts were performed on force plates to investigate ground reaction forces, reaction time and total sprint time. Analysis showed significant differences in sprint times, with NORM (1.77±0.10 s) being faster than FFS (1.81±0.12 s) and BFS (2.01±0.13 s), and FFS being faster than BFS, although no differences were found in reaction time. In terms of mean force and power, NORM (331.1±39.2N, 542.2±72.3W) and FFS (320.8±43.2N, 550.9±81.4W) were significantly larger than BFS (256.9±36.2N, 443.5±61.1W). This indicates that when starting from a staggered stance, the BFS is inferior to the others and should be avoided. However, since the force profiles of the NORM and the FFS were similar, the differences in sprint time could arise from a technique bias towards the NORM start.

Ground Reaction Forces in Children’s Gait

1989 ◽  
Vol 1 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Nancy L. Greer ◽  
Joseph Hamill ◽  
Kevin R. Campbell
Keyword(s):  
Sex Differences ◽  
Ground Reaction Force ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Reaction Forces ◽  
Braking Force ◽  
Force Components ◽  
Age Range ◽  
Minimum Force

Ground reaction force patterns during walking were observed in 18 children 3 and 4 years of age. The children walked barefoot at a self-chosen walking pace. Selected variables representing the vertical, anteroposterior, and mediolateral force components were evaluated. The results indicated that children in this age range contact the ground with greater vertical force measures relative to body mass than do adults. In addition, the minimum vertical force was lower, the transition from braking to propulsion occurred earlier, and the mediolateral force excursions were higher than typically found in adults. When the children were divided into groups on the basis of sex, differences were observed between those groups. The boys exhibited a greater difference in the vertical peak forces, a lower minimum force, a greater braking force, and a higher mediolateral force excursion value. The results indicated that children display a different ground reaction force pattern than do adults and that differences between boys and girls may be observed as early as ages 3 and 4 years.

Obesity: Effects on Gait in an Osteoarthritic Population

1996 ◽  
Vol 12 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Stephen P. Messier ◽  
Walter H. Ettinger ◽  
Thomas E. Doyle ◽  
Timothy Morgan ◽  
Margaret K. James ◽  
...  
Keyword(s):  
Older Adults ◽  
High Speed ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Kinematic Data ◽  
Knee Oa ◽  
Significant Relationships ◽  
Gait Mechanics ◽  
Reaction Forces ◽  
Walking Velocity

The purpose of our study was to examine the association between obesity and gait mechanics in older adults with knee osteoarthritis (OA). Subjects were 101 older adults (25 males and 76 females) with knee OA. High-speed video analysis and a force platform were used to record sagittal view lower extremity kinematic data and ground reaction forces. Increased body mass index (BMI) was significantly related to both decreases in walking velocity and knee maximum extension. There were no significant relationships between BMI and any of the hip or ankle kinematic variables. BMI was directly related to vertical force minimum and maximum values, vertical impulse, and loading rate. Increases in braking and propulsive forces were significantly correlated with increased BMI. Maximum medially and laterally directed ground reaction forces were positively correlated with BMI. Our results suggests that, in subjects with knee OA, obesity is associated with an alteration in gait.

INFLUENCE OF STEPPING CUE ON STEP REACTION TIME, EMG, AND GROUND REACTION FORCES

2006 ◽  
Vol 30 (4) ◽  
pp. 214
Author(s):  
S. L. Brown ◽  
A. F. Gregory ◽  
C. G. Kukulka ◽  
M. L. Pommier ◽  
A. B. Simone
Keyword(s):  
Reaction Time ◽  
Ground Reaction Forces ◽  
Reaction Forces

scholarly journals Stabilization demands of walking modulate the vestibular contributions to gait

2020 ◽  
Author(s):  
Rina M. Magnani ◽  
Sjoerd M. Bruijn ◽  
Jaap H. van Dieën ◽  
Patrick A. Forbes
Keyword(s):  
Dynamic Stability ◽  
Vestibular Stimulation ◽  
Erector Spinae ◽  
Medial Gastrocnemius ◽  
Ground Reaction Forces ◽  
Local Dynamic ◽  
Control Effort ◽  
Gait Stability ◽  
Local Dynamic Stability ◽  
Reaction Forces

AbstractStable walking relies critically on motor responses to signals of head motion provided by the vestibular system, which are phase-dependent and modulated differently within each muscle. It is unclear, however, whether these vestibular contributions also vary according to the stability of the walking task. Here we investigate how vestibular signals influence muscles relevant for gait stability (medial gastrocnemius, gluteus medius and erector spinae) – as well as their net effect on ground reaction forces – while humans walked normally, with mediolateral stabilization, wide and narrow steps. We estimated coherence of electrical vestibular stimulation (EVS) with muscle activity and mediolateral ground reaction forces, together with local dynamic stability of trunk kinematics. Walking with external stabilization increased local dynamic stability and decreased coherence between EVS and all muscles/forces compared to normal walking. Wide-base walking also decreased vestibulo-motor coherence, though gait stability did not differ. Conversely, narrow-base walking increased local dynamic stability, but produced muscle-specific increases and decreases in coherence that resulted in a net increase in vestibulo-motor coherence with ground reaction forces. Overall, our results show that while vestibular contributions may vary with gait stability, they more critically depend on the stabilization demands (i.e. control effort) needed to maintain a stable walking pattern.

Measurement of ground reaction forces in cats 1 year after femoral head and neck ostectomy

2020 ◽  
pp. 1098612X2094814
Author(s):  
Eva Schnabl-Feichter ◽  
Sophia Schnabl ◽  
Alexander Tichy ◽  
Michaela Gumpenberger ◽  
Barbara Bockstahler
Keyword(s):  
Femoral Head ◽  
Head And Neck ◽  
Small Animal ◽  
Control Group ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Gait Abnormality ◽  
Pressure Sensitive ◽  
Reaction Forces

Objectives The objective of this study was to compare ground reaction forces (GRFs) of a group of cats after femoral head and neck ostectomy (FHO) with those of a historical control group. Methods We searched the database of the Small Animal Clinic of the Veterinary University in Vienna for cats that had undergone unilateral FHO at least 1 year previously. Owners were telephoned and invited to the clinic with their cats for a re-examination. An in-house owner questionnaire-based evaluation, complete orthopaedic examination, hip radiography and gait analysis with a pressure-sensitive plate were performed, and results were compared within and between groups (FHO group and control group [CG]). Results Seventeen cats that had undergone FHO (FHO group) at least 1 year previously and 15 healthy cats (CG) from a previous study were included. Measured GRFs (peak vertical force and vertical impulse [IFz] normalised to total force [%TF]) of the FHO legs were lower than those of the other legs of the FHO group and the legs of the CG. Results of the owner questionnaire were generally good and did not match the results of the GRF comparison. Furthermore, the gaits evaluated during the orthopaedic examination did not correlate with the measured GRFs where we identified a certain degree of lameness (reduced IFz, %TF) in all cats. Cats with limb shortening (dorsally displaced major trochanter major) were not revealed to have different GRF measurements. Conclusions and relevance This is the first study to assess GRFs in a large group of cats that had undergone FHO, comparing findings with those in healthy cats. Even if the differences are statistically significant, but rather small, our findings point to a long-term residual gait abnormality that could be detected using a pressure-sensitive plate but not always with an orthopaedic examination, in cats 1 year after FHO.

scholarly journals Comparison of the Vertical Force Distribution in the Paws of Dogs with Coxarthrosis and Sound Dogs Walking over a Pressure Plate

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 986 ◽  
Author(s):  
Jane P. L. Moreira ◽  
Alexander Tichy ◽  
Barbara Bockstahler
Keyword(s):  
Hind Limb ◽  
Stance Phase ◽  
Force Distribution ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Phase Duration ◽  
Contralateral Limb ◽  
Pressure Plate ◽  
Reaction Forces

In the present study, we used a pressure plate to investigate the ground reaction forces of limbs and the vertical force distribution (VFD) within the paws of dogs with coxarthrosis. We included 23 sound dogs (GSou) and 23 dogs with hip osteoarthrosis (GCox). The dogs walked over a pressure plate and the peak vertical force (PFz), vertical impulse (IFz) as the percentage of the total force, and time of occurrence of PFz as a percent of the stance phase duration (TPFz%) were evaluated, as well for the entire limb as in the paws (where the paws were divided into four quadrants). The GCox presented a lower PFz% in the lame hind limb than in others and transferred the weight to the caudal quadrants of the front limbs. IFz% was lower in the lame limb and was counterbalanced through higher loading of the caudal quadrants in all unaffected limbs. TPFz% was reached later in the lame limb than in the contralateral limb and the GSou, specifically in the caudomedial quadrant. In conclusion, we found complex compensatory effects of lameness in the hind limb, and this methodology was useful to define the VFD within the paws of dogs.

scholarly journals Effect of trans-tibial prosthesis pylon flexibility on ground reaction forces during gait

2001 ◽  
Vol 25 (3) ◽  
pp. 195-201 ◽  
Author(s):  
K. L. Coleman ◽  
D. A. Boone ◽  
D. G. Smith ◽  
J. M. Czerniecki
Keyword(s):  
Loading Rate ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Force Curve ◽  
Vertical Loading ◽  
Reaction Forces ◽  
Stance Time ◽  
Step Down ◽  
Weight Acceptance

This study explored the effects of trans-tibial prosthesis pylon flexibility on ground reaction forces (GRFs) associated with walking and step-down. Four (4) active subjects with unilateral trans-tibial amputation and pylon lengths ranging from 4.9cm to 25.9cm were studied wearing an aluminium (rigid) pylon and a nylon (more flexible) pylon. Ground reaction forces were collected for the amputated limb during walking at pre-measured self-selected velocity and when stepping down from a 20cm box. Pylon material significantly affected the magnitudes and patterns of GRFs in both tests. During walking, the most notable differences were seen in the anteroposterior (AP) direction. With the flexible pylon, the AP propulsive peak was greater (p=0.031), and the irregularities in the AP force curve were reduced. Additionally, when walking with the flexible pylon, the vertical peak associated with weight acceptance occurred earlier (p=0.010), the vertical terminal stance peak occurred later (p=0.012), and stance time was longer (p=0.010). During step-down, the vertical loading rate (p=0.010) and the peak vertical force (p=0.010) were greater with the more flexible pylon. Subjective feedback indicated that subjects could distinguish between the two pylons and felt that the nylon component was more comfortable, more flexible, and would enable them to walk more quickly. These results suggest that the pylon may be an influential component of the prosthesis with respect to gait and comfort, and that some degree of flexibility is desirable.

Kinetic Gait Analysis of Agility Dogs Entering the A-Frame

2019 ◽  
Vol 32 (02) ◽  
pp. 097-103 ◽  
Author(s):  
Mark Glyde ◽  
Giselle Hosgood ◽  
Alasdair Dempsey ◽  
Sarah Wickham ◽  
Carla Appelgrein
Keyword(s):  
Stance Phase ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Propulsive Force ◽  
Forward Movement ◽  
Impact Peak ◽  
Force Peak ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

Objective The main purpose of this study was to investigate the effect of a decrease in the A-frame angle of incline on the vertical and cranio-caudal ground reaction forces observed in a homogeneous cohort of agility dogs during entrance and contact with the A-frame. Materials and Methods A crossover study design was applied to eight large breed dogs to compare the vertical and cranio-caudal ground reaction forces entering the A-frame at three angles of incline: 40° (standard), 35° and 30°. The peak vertical force, passive impact peak, peak propulsive force, peak braking force, the time point (percentile) in the stance phase at which these events occurred and the proportion of time for limb contact spent in braking (% braking) and propulsion (% propulsion) were examined.The variables measured from three trials at each incline were evaluated for a significant effect of A-frame angle with height and velocity included as covariates. Results The peak propulsive force and the % propulsion were significantly higher at the 40° angle of incline compared with 30° (p = 0.013, p = 0.0165 respectively) and the % braking was significantly lower at the 40° angle of incline compared with 30° (p = 0.0165). There was no significant effect of A-frame angle on the vertical ground reaction forces measured. Clinical Significance Compared with 30° incline, ascent up the A-frame at a 40° incline requires a higher propulsive force and extended time in propulsion to maintain forward movement and convert potential energy into forward kinetic energy.

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