scholarly journals Impacto producido por la técnica seoi-otoshi. Relación con años de práctica y grado en judo

2014 ◽  
Vol 9 (1) ◽  
pp. 32 ◽  
Author(s):  
Carlos Montero Carretero ◽  
José Luis López Elvira
Keyword(s):  
Body Weight ◽  
Potential Risk ◽  
The Other ◽  
Ground Reaction Forces ◽  
Expert Group ◽  
Risk Of Injury ◽  
Force Peak ◽  
Reaction Forces ◽  
The Mean ◽  
The Impact

Judokas commonly train the <em>seoi-otoshi</em> technique (aka, drop-knee <em>seoi-nage</em>). A controversy exists about the convenience of its use by the younger judokas due to the risk of high loads produced by the impacts on their growing structures. The aim of the present paper was to measure the impacts against the tatami when executing the knee <em>seoi-otoshi</em> technique and its relationship with the years of practice and the degree or level (color of the belt). Thirty-three judokas from different years and degree volunteered to participate. Two force plates covered by standard tatami, registered the ground reaction forces while five consecutive repetitions were executed. We measured the mean and maximum peaks of force relative to their own body weight (BW). The results show peaks of more than 10 BW, which can be considered a potential risk of injury in the younger judokas, especially when repeated in time. In addition, a tendency to decrease the impact as the years of practice increase is observed (potential function; R<sup>2</sup>= 0.41, p&lt;0.000 in the force peak), and the force in the expert group has been significantly lower than in the other groups (p&lt;0.001). On the other hand, the degree (belt color) shows a quadratic relationship (R<sup>2</sup>= 0.45, p&lt;0.000 in the force peak). The lack of agreement between the years of practice and the degree shows that the promotion criteria does not appear to be a valid one from a preventive viewpoint, especially in the lower degrees which would correspond to younger practitioners whose locomotor structures are still not fully developed.

scholarly journals Ground Reaction Forces of Dressage Horses Performing the Piaffe

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 436 ◽  
Author(s):  
Hilary Mary Clayton ◽  
Sarah Jane Hobbs
Keyword(s):  
Coefficient Of Variation ◽  
Three Dimensional ◽  
Individual Variability ◽  
The Other ◽  
Ground Reaction Forces ◽  
High Coefficient ◽  
Reaction Forces

The piaffe is an artificial, diagonally coordinated movement performed in the highest levels of dressage competition. The ground reaction forces (GRFs) of horses performing the piaffe do not appear to have been reported. Therefore, the objective of this study was to describe three-dimensional GRFs in ridden dressage horses performing the piaffe. In-ground force plates were used to capture fore and hindlimb GRF data from seven well-trained dressage horses. Peak vertical GRF was significantly higher in forelimbs than in the hindlimbs (7.39 ± 0.99 N/kg vs. 6.41 ± 0.64 N/kg; p < 0.001) with vertical impulse showing a trend toward higher forelimb values. Peak longitudinal forces were small with no difference in the magnitude of braking or propulsive forces between fore and hindlimbs. Peak transverse forces were similar in magnitude to longitudinal forces and were mostly directed medially in the hindlimbs. Both the intra- and inter-individual variability of longitudinal and transverse GRFs were high (coefficient of variation 25–68%). Compared with the other diagonal gaits of dressage horses, the vertical GRF somewhat shifted toward the hindlimbs. The high step-to-step variability of the horizontal GRF components is thought to reflect the challenge of balancing on one diagonal pair of limbs with no forward momentum.

Seasonal variations in wool growth and heat tolerance of sheep. I. Wool growth

1960 ◽  
Vol 11 (1) ◽  
pp. 75 ◽  
Author(s):  
M Wodzicka
Keyword(s):  
Body Weight ◽  
Day Treatment ◽  
The Other ◽  
Seasonal Rhythm ◽  
Group Iii ◽  
Wool Growth ◽  
Group I ◽  
The Mean ◽  
Group Ii ◽  
The Difference

The monthly wool growth of three groups of rams was studied at Beltsville, Maryland. Group I received natural daylight (at 38° 53' N.) and was shorn monthly. Group II had a 7:17 hours of daylight to hours of darkness rhythm and was shorn every 6 months, once in winter and once in summer. Group III received natural daylight and was likewise shorn every 6 months. The rams of all groups produced more wool in summer than in winter. This difference was significant (P<0.001). The mean body weight and food intake were both greater in the winter months, which indicated that the seasonal rhythm of wool growth was not a consequence of poorer feeding in winter. The rams which were shorn monthly (group I) grew considerably more wool than the other two groups, but the difference was not statistically significant. The short-day treatment of group II did not increase the annual wool production nor decrease the seasonal rhythm of wool growth. The balance of evidence from this and other experiments indicates that temperature rather than light controls the seasonal rhythm of wool growth.

Footwear and Elevated Heel Influence On Barbell Back Squat: a Review

2021 ◽  
Author(s):  
Aaron Michael Pangan ◽  
Matthew J Leineweber
Keyword(s):  
Ground Reaction Forces ◽  
Specific Effects ◽  
Back Squat ◽  
Running Shoes ◽  
Different Types ◽  
Reaction Forces ◽  
Joint Loads ◽  
The Impact ◽  
Kinematics And Kinetics ◽  
Full Body

Abstract The back squat is one of the most effective exercises in strengthening the muscles of the lower extremity. Understanding the impact of footwear has on the biomechanics is imperative for maximizing the exercise training potential, preventing injury, and rehabilitating from injury. This review focuses on how different types of footwear affect the full-body kinematics, joint loads, muscle activity, and ground reaction forces in athletes of varying experience performing the weighted back squat. The literature search was conducted using three databases, and fourteen full-text articles were ultimately included in the review. The majority of these studies demonstrated that the choice of footwear directly impacts kinematics and kinetics. Weightlifting shoes were shown to decrease trunk lean and generate more plantarflexion relative to running shoes and barefoot lifting. Elevating the heel through the use of external squat wedges is popular clinical exercise during rehabilitation and was shown to provide similar effects to WLS. Additional research with a broader array of populations, particularly novice and female weightlifters, should be conducted to generalize the research results to non-athlete populations. Further work is also needed to characterize the specific effects of sole stiffness and heel elevation height on squatting mechanics.

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 Impact Of Financial Crisis On Islamic And Conventional Indices Of The GCC Countries

2015 ◽  
Vol 31 (2) ◽  
pp. 357 ◽  
Author(s):  
Hela Miniaoui ◽  
Hameedah Sayani ◽  
Anissa Chaibi
Keyword(s):  
Financial Crisis ◽  
The Other ◽  
Garch Models ◽  
Use Of Data ◽  
Market Index ◽  
Gcc Countries ◽  
Mean And Variance ◽  
The Mean ◽  
The Impact ◽  
Study Performance

<p>We study performance of Islamic and conventional indices of the Gulf Cooperation Council (GCC) countries in the wake of financial crisis of 2008 and test whether Islamic indices were less risky than conventional indices. We make use of data of the six GCC markets as well as the Dow Jones Islamic Market Index GCC. The mean and variance of each of the indices are analyzed based on augmented GARCH models. The results show that the financial crisis impacted on the mean returns of Bahrain, the other indices remained unaffected. The financial crisis, however, impacted volatility in three GCC markets (Kuwait, Bahrain, and the UAE), while the impact on the remaining markets (Saudi Arabia, Oman, and Qatar) and the Islamic index was insignificant. More interestingly, we show that the Islamic index did not exhibit lower volatility than its conventional counterparts.</p>

Effect of prolonged undernutrition on the recovery and reproductive performance of maiden Merino ewes

1967 ◽  
Vol 7 (24) ◽  
pp. 7 ◽  
Author(s):  
P McInnes ◽  
TJ Grainger ◽  
MD Smith
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
New South ◽  
New South Wales ◽  
The Other ◽  
First Year ◽  
Treatment Groups ◽  
South Wales ◽  
Feeding Trials ◽  
The Mean

Data are presented on the recovery and reproductive performance of 2 1/2-year-old maiden Merino ewes after a prolonged period of undernutrition. The 217 sheep had been hand-fed on a submaintenance ration in pen feeding trials at Glenfield, New South Wales. During the seven months of the trials they had lost 6 kg (28 to 22 kg) body weight. They were transported to Condobolin in south-western New South Wales, divided into two treatment groups and run on good quality pastures. One group was joined immediately (May 1959) and again ten months later, and the other group was mated after six months at Condobolin (in October 1959) and again 12 months later. The ewes recovered rapidly. The mean weight of both groups had reached 30 kg within six weeks and 40 kg within six months. In the first year 73 of the 100 May-mated ewes bore lambs, but only 38 of these lambs were weaned. Ewes bearing lambs had a higher body weight at the start of joining and gained more during joining than the barren ewes. At the other three joinings (October 1959, May 1960, October 1960) lambing percentage was from 86-89 and weaning percentage from 62-69-both normal for the district. The proportion of twin lambs (3-6 per cent) was low. Wool weight in 1959 was not affected by time of mating or by pregnancy.

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.

Autologous Hematopoietic Stem Cell Transplantation for Crohn’s Diseases - 5 Cases Report.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5437-5437
Author(s):  
Jian Ouyang ◽  
Longdian Chen ◽  
Bing Chen ◽  
Jingyan Xu ◽  
Cuiping Li ◽  
...  
Keyword(s):  
T Cells ◽  
Body Weight ◽  
Abdominal Pain ◽  
Abdominal Discomfort ◽  
The Other ◽  
Cd34 Cells ◽  
Rectovesical Fistula ◽  
The Mean ◽  
Crohn’S Diseases ◽  
Mild Diarrhea

Abstract Nowadays it is widely used as glucocorticoids, ortho-oxybenzoic acid, immunosuppressive agents and biological agents for Crohn’s Disease. But all these agents can only control the symptoms rather than curing the diseases. About 70% patients need surgery in the course. 5 patents of Crohn’s Diseases have received AHSCT in our department since 2004. These patients, including 3 male and 2 female, with a mean age of 32 (range, 23~46), were final confirmed by enteroscope and histology. The mean CDAI of these patients was 213 points (range, 170~256), and the mean interval between invasion and transplantation was 63 months (range, 27~132 months). All the patients had mild or severe diarrhea and abdominal pain, one of them have a 6cm×7cm lump touchable in the abdominal region, while one of them complicated with vesicorectal fistula. These patients were mainly treated with glucocorticoids, SASP, cyclophosphamide (CTX), et al, which didn’t control the condition. Mobilization program was CTX 2g/m2 for 2 days and G-CSF 5~10 μg/kg/d on the 5th day of medication. Leukapheresis was initiated when WBC>5.0×109/L. The collections of CD34+ cells from two cases were over 4×106/kg, and ClinMACs cell separation system was used to purify the CD34+ cells and to deplete T cells. Two collections of CD34+ cells were 1.3×106/kg and 2.8×106/kg, respectively, and then were kept in −80°. And the other case failed in the collection, and then was treated with bone marrow transplantation. The conditioning programs were MC (CTX 60mg/kg -2, -1d;melphalan 140mg/m2 -2d) for one case, and CTX 50mg/kg×4d for the other 4 cases. 2 of the 3 patients without in vitro purification of CD34+ cells to deplete T cells were treated with rabbit antithymocyte globulin 5 mg/kg on day-2 and day -1 for T cell depletion. The mean CD34+ cells infused was 1.4×106/kg(range, 1.3×106/kg~2.8×106/kg). Neutrophile granulocyteand>0.5×109/L occurred at day +10~+12, while platelet>2.0×109/L occurred at day +9~+11. Fever occurred in all patients in the granulocytopenia phase, and lasted from 1 to 3 weeks. One of the patients complicated with ESBL+ ichoremia, and was cured with antibiotics. After the transplantation, 2 patients were treated with prednisone 10mg/d as maintenance therapy, and the other 3 stopped using antidiarrheal and glucocorticoids. 4 patients got free of abdominal pain and diarrhea in the following 2~3 months, and the other did in 1 year. The average body weight of the patients increased 11.2 kg (range, 3~20kg) 3 months after transplantation. The mean follow-up was 16 months. 2 patients have been maintaining remission until now. The lump in the abdomen of one of these 2 patient decreased from 6×7cm to 5×5cm, which was resected 19 months after transplantation. And this patient is still in remission now. 3 patients relapsed after 4~8 months of remission. One of them relapsed 5months after transplantation and died complicated with peritonitis in 7 months. One patient relapsed in 8 months with abdominal discomfort, mild diarrhea, and decreasing of body weight. The other complicated with rectovesical fistula showed closure of syrinx by barium enema, and suffered abdominal discomfort, mild diarrhea, and decreasing of body weight too 4 months after transplantation, then relapsed with rectovesical fistula 8 months after transplantation. HSCT for Crohn’s disease is safe and effective. However, it has a comparative higher relapse rate.

scholarly journals Effects of Velocity and Weight Support on Ground Reaction Forces and Metabolic Power during Running

2008 ◽  
Vol 24 (3) ◽  
pp. 288-297 ◽  
Author(s):  
Alena M. Grabowski ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Normal Weight ◽  
Treadmill Running ◽  
Ground Reaction Forces ◽  
Metabolic Power ◽  
Data Set ◽  
Weight Support ◽  
Scientific Goal ◽  
Reaction Forces ◽  
Support Body Weight

The biomechanical and metabolic demands of human running are distinctly affected by velocity and body weight. As runners increase velocity, ground reaction forces (GRF) increase, which may increase the risk of an overuse injury, and more metabolic power is required to produce greater rates of muscular force generation. Running with weight support attenuates GRFs, but demands less metabolic power than normal weight running. We used a recently developed device (G-trainer) that uses positive air pressure around the lower body to support body weight during treadmill running. Our scientific goal was to quantify the separate and combined effects of running velocity and weight support on GRFs and metabolic power. After obtaining this basic data set, we identified velocity and weight support combinations that resulted in different peak GRFs, yet demanded the same metabolic power. Ideal combinations of velocity and weight could potentially reduce biomechanical risks by attenuating peak GRFs while maintaining aerobic and neuromuscular benefits. Indeed, we found many combinations that decreased peak vertical GRFs yet demanded the same metabolic power as running slower at normal weight. This approach of manipulating velocity and weight during running may prove effective as a training and/or rehabilitation strategy.

The Effects of Uni- and Bilateral Fatigue on Postural and Power Tasks

2013 ◽  
Vol 29 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Paulo H. Marchetti ◽  
Maria I.V. Orselli ◽  
Marcos Duarte
Keyword(s):  
Lower Limb ◽  
Healthy Subjects ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Lower Limbs ◽  
Quiet Standing ◽  
Ground Reaction Forces ◽  
Before And After ◽  
Reaction Forces ◽  
The Mean

The aim of this study was to investigate the effects of unilateral and bilateral fatigue on both postural and power bipedal tasks. Ten healthy subjects performed two tasks: bipedal quiet standing and a maximal bipedal counter-movement jumping before and after unilateral (with either the dominant or nondominant lower limb) and bilateral (with both lower limbs) fatigue. We employed two force plates (one under each lower limb) to measure the ground reaction forces and center of pressure produced by subjects during the tasks. To quantify the postural sway during quiet standing, we calculated the resultant center of pressure (COP) speed and COP area of sway, as well as the mean weight distribution between lower limbs. To quantify the performance during the countermovement jumping, we calculated the jump height and the peak force of each lower limb. We observed that both unilateral and bilateral fatigue affected the performance of maximal voluntary jumping and standing tasks and that the effects of unilateral and bilateral fatigue were stronger in the dominant limb than in the nondominant limb during bipedal tasks. We conclude that unilateral neuromuscular fatigue affects both postural and power tasks negatively.

Sign in / Sign up

Export Citation Format

Share Document