Comparison of crossover and jab step start techniques in sprinting for football and handball players

2021 ◽  
pp. 174795412110664
Author(s):  
Tomohisa Miyanishi ◽  
Yifan Chen ◽  
Kazuhito Shibayama ◽  
Ryu Nagahara
Keyword(s):  
Sagittal Plane ◽  
Plantar Flexion ◽  
Waveform Analysis ◽  
Contributing Factors ◽  
Joint Power ◽  
Male Athletes ◽  
External Power ◽  
The Difference ◽  
Hip Extension ◽  
Ankle Plantar Flexion

There are two techniques for a lateral sprint start: crossover (CS) and jab step (JS) starts. This study aimed to elucidate the difference in the CS and JS starts in terms of sprint performance and leg kinetics in athletes from ball-and-goal type sports (e.g. soccer and handball). Nineteen male athletes performed CS and JS starts, during which their motion and the force they applied to the ground were simultaneously recorded using a motion-capture system and two force platforms. The results showed that, although 5-m time via video analysis did not differ between CS and JS starts, forward velocity of centre of gravity (CG) and normalised average horizontal external power were greater for the JS start than the CS start. From waveform analysis, greater positive joint power in the sagittal plane leading to greater positive work in the JS start were found in the first three quarters of the push-off phase for rear hip extension and in the subsequent push-off phase for rear ankle plantar flexion. In conclusion, the results suggest that the JS start is superior to the CS start for start quickness, though the gains in the start did not appear to transfer to the 5-m performance. Moreover, greater positive joint power in the first three quarters of the push-off phase for the rear hip extension and in the subsequent push-off phase for the rear ankle plantar flexion were considered to be important contributing factors to the better performance of the JS start.

The Effect of Increasing Jump Steps on Stance Leg Joint Kinetics in Bounding

2018 ◽  
Vol 39 (09) ◽  
pp. 661-667 ◽  
Author(s):  
Yasushi Kariyama ◽  
Hiroaki Hobara ◽  
Koji Zushi
Keyword(s):  
Plantar Flexion ◽  
Standing Position ◽  
Knee Extension ◽  
Joint Work ◽  
Joint Power ◽  
Male Athletes ◽  
Joint Kinetics ◽  
Jump Distance ◽  
Hip Abduction ◽  
Hip Extension

AbstractJump distance per step in bounding exercises from the standing position increases with increasing number of steps. We examined the hypothesis that the joint kinetic variables of the stance leg would also increase accordingly. Eleven male athletes (sprinters and jumpers) performed bounding exercise, starting from the double-leg standing posture, and covered the longest distance possible by performing a series of seven forward alternating single-leg jumps. Kinematic and kinetic data were calculated using the data by a motion capture system and force platforms. Hip extension joint work were decreased at third step (1st: 1.07±0.22, 3rd: 0.45±0.15, 5th: 0.47±0.14 J•kg−1; partial η2: 0.86), and hip abduction joint power were increased (1st: 7.53±3.29, 3rd: 13.50±4.44, 5th: 21.37±9.93 W•kg−1; partial η2: 0.58); the knee extension joint power were increased until the third step (1st: 14.43±4.94, 3rd: 17.13±3.59, 5th: 14.28±2.86 W•kg−1; partial η2: 0.29), and ankle plantar flexion joint power increased (1st: 34.14±5.33, 3rd: 37.46±4.45, 5th: 40.11±5.66 W•kg−1; partial η2: 0.53). These results contrast with our hypothesis, and indicate that increasing the jump distance during bounding exercises is not necessarily accompanied by increases in joint kinetics of stance leg. Moreover, changes in joint kinetics vary at different joints and anatomical axes.

Functional Data Analyses for the Assessment of Joint Power Profiles During Gait of Stroke Subjects

2014 ◽  
Vol 30 (2) ◽  
pp. 348-352 ◽  
Author(s):  
André G. P. Andrade ◽  
Janaine C. Polese ◽  
Leopoldo A. Paolucci ◽  
Hans-Joachim K. Menzel ◽  
Luci F. Teixeira-Salmela
Keyword(s):  
Power Generation ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Knee Extension ◽  
Mathematical Function ◽  
Joint Power ◽  
Gait Biomechanics ◽  
Isolated Points ◽  
Parametric Analyses

Lower extremity kinetic data during walking of 12 people with chronic poststroke were reanalyzed, using functional analysis of variance (FANOVA). To perform the FANOVA, the whole curve is represented by a mathematical function, which spans the whole gait cycle and avoids the need to identify isolated points, as required for traditional parametric analyses of variance (ANOVA). The power variables at the ankle, knee, and hip joints, in the sagittal plane, were compared between two conditions: With and without walking sticks at comfortable and fast speeds. For the ankle joint, FANOVA demonstrated increases in plantar flexion power generation during 60–80% of the gait cycle between fast and comfortable speeds with the use of walking sticks. For the knee joint, the use of walking sticks resulted in increases in the knee extension power generation during 10–30% of the gait cycle. During both speeds, the use of walking sticks resulted in increased power generation by the hip extensors and flexors during 10–30% and 40–70% of the gait cycle, respectively. These findings demonstrated the benefits of applying the FANOVA approach to improve the knowledge regarding the effects of walking sticks on gait biomechanics and encourage its use within other clinical contexts.

Joint-Specific Power-Pedaling Rate Relationships During Maximal Cycling

2014 ◽  
Vol 30 (3) ◽  
pp. 423-430 ◽  
Author(s):  
John McDaniel ◽  
N. Scott Behjani ◽  
Steven J. Elmer ◽  
Nicholas A.T. Brown ◽  
James C. Martin
Keyword(s):  
Repeated Measures ◽  
Control Strategies ◽  
Plantar Flexion ◽  
Knee Extension ◽  
Specific Power ◽  
Rate Relationship ◽  
S Cycling ◽  
Hip Extension ◽  
Ankle Plantar Flexion ◽  
Pedaling Rate

Previous authors have reported power-pedaling rate relationships for maximal cycling. However, the joint-specific power-pedaling rate relationships that contribute to pedal power have not been reported. We determined absolute and relative contributions of joint-specific powers to pedal power across a range of pedaling rates during maximal cycling. Ten cyclists performed maximal 3 s cycling trials at 60, 90, 120, 150, and 180 rpm. Joint-specific powers were averaged over complete pedal cycles, and extension and flexion actions. Effects of pedaling rate on relative joint-specific power, velocity, and excursion were assessed with regression analyses and repeated-measures ANOVA. Relative ankle plantar flexion power (25 to 8%;P= .01;R2= .90) decreased with increasing pedaling rate, whereas relative hip extension power (41 to 59%;P< .01;R2= .92) and knee flexion power (34 to 49%;P< .01;R2= .94) increased with increasing pedaling rate. Knee extension powers did not differ across pedaling rates. Ankle joint angular excursion decreased with increasing pedaling rate (48 to 20 deg) whereas hip joint excursion increased (42 to 48 deg). These results demonstrate that the often-reported quadratic power-pedaling rate relationship arises from combined effects of dissimilar joint-specific power-pedaling rate relationships. These dissimilar relationships are likely influenced by musculoskeletal constraints (ie, muscle architecture, morphology) and/or motor control strategies.

Mechanics of Jazz Shoes and Their Effect on Pointing in Child Dancers

2012 ◽  
Vol 28 (3) ◽  
pp. 242-248 ◽  
Author(s):  
Alycia Fong Yan ◽  
Richard Smith ◽  
Benedicte Vanwanseele ◽  
Claire Hiller
Keyword(s):  
Muscle Activation ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Scientific Investigation ◽  
3D Motion Analysis ◽  
Technical Requirements ◽  
Foot Motion ◽  
The Aesthetic ◽  
The Impact ◽  
Ankle Plantar Flexion

There has been little scientific investigation of the impact of dance shoes on foot motion or dance injuries. The pointed (plantar-flexed) foot is a fundamental component of both the technical requirements and the traditional aesthetic of ballet and jazz dancing. The aims of this study were to quantify the externally observed angle of plantar flexion in various jazz shoes compared with barefoot and to compare the sagittal plane bending stiffness of the various jazz shoes. Sixteen female recreational child dancers were recruited for 3D motion analysis of active plantar flexion. The jazz shoes tested were a split-sole jazz shoe, full-sole jazz shoe, and jazz sneaker. A shoe dynamometer measured the stiffness of the jazz shoes. The shoes had a significant effect on ankle plantar flexion. All jazz shoes significantly restricted the midfoot plantar flexion angle compared with the barefoot condition. The split-sole jazz shoe demonstrated the least restriction, whereas the full-sole jazz shoe the most midfoot restriction. A small restriction in metartarsophalangeal plantar flexion and a greater restriction at the midfoot joint were demonstrated when wearing stiff jazz shoes. These restrictions will decrease the aesthetic of the pointed foot, may encourage incorrect muscle activation, and have an impact on dance performance.

Legal Update: North Dakota Supreme Court: Third Edition of Guides is “Most Current”

1999 ◽  
Vol 4 (1) ◽  
pp. 6-7
Author(s):  
James J. Mangraviti
Keyword(s):  
Internal Rotation ◽  
External Rotation ◽  
Measurement Techniques ◽  
Fourth Edition ◽  
Hip Motion ◽  
The Difference ◽  
The Right ◽  
Hip Flexion ◽  
Hip Rotation ◽  
Hip Extension

Abstract The accurate measurement of hip motion is critical when one rates impairments of this joint, makes an initial diagnosis, assesses progression over time, and evaluates treatment outcome. The hip permits all motions typical of a ball-and-socket joint. The hip sacrifices some motion but gains stability and strength. Figures 52 to 54 in AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, illustrate techniques for measuring hip flexion, loss of extension, abduction, adduction, and external and internal rotation. Figure 53 in the AMA Guides, Fourth Edition, illustrates neutral, abducted, and adducted positions of the hip and proper alignment of the goniometer arms, and Figure 52 illustrates use of a goniometer to measure flexion of the right hip. In terms of impairment rating, hip extension (at least any beyond neutral) is irrelevant, and the AMA Guides contains no figures describing its measurement. Figure 54, Measuring Internal and External Hip Rotation, demonstrates proper positioning and measurement techniques for rotary movements of this joint. The difference between measured and actual hip rotation probably is minimal and is irrelevant for impairment rating. The normal internal rotation varies from 30° to 40°, and the external rotation ranges from 40° to 60°.

scholarly journals Force Generation on the Hallux Is More Affected by the Ankle Joint Angle than the Lesser Toes: An In Vivo Human Study

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 48
Author(s):  
Junya Saeki ◽  
Soichiro Iwanuma ◽  
Suguru Torii
Keyword(s):  
Repeated Measures ◽  
Joint Angle ◽  
Plantar Flexion ◽  
Human Study ◽  
Force Generation ◽  
Functional Difference ◽  
Multiple Comparison Test ◽  
The Difference ◽  
Metatarsophalangeal Joints

The structure of the first toe is independent of that of the other toes, while the functional difference remains unclear. The purpose of this study was to investigate the difference in the force generation characteristics between the plantar-flexion of the first and second–fifth metatarsophalangeal joints (MTPJs) by comparing the maximal voluntary plantar-flexion torques (MVC torque) at different MTPJs and ankle positions. The MVC torques of the first and second–fifth MTPJs were measured at 0°, 15°, 30°, and 45° dorsiflexed positions of the MTPJs, and at 20° plantar-flexed, neutral, and 20° dorsiflexed positions of the ankle. Two-way repeated measures analyses of variance with Holm’s multiple comparison test (MTPJ position × ankle position) were performed. When the MTPJ was dorsiflexed at 0°, 15°, and 30°, the MVC torque of the first MTPJ when the ankle was dorsiflexed at 20° was higher than that when the ankle was plantar-flexed at 20°. However, the ankle position had no significant effect on the MVC torque of the second–fifth MTPJ. Thus, the MVC torque of the first MTPJ was more affected by the ankle position than the second–fifth MTPJs.

scholarly journals IMU-Based Effects Assessment of the Use of Foot Orthoses in the Stance Phase during Running and Asymmetry between Extremities

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3277
Author(s):  
Juan Luis Florenciano Restoy ◽  
Jordi Solé-Casals ◽  
Xantal Borràs-Boix
Keyword(s):  
Contact Time ◽  
Stance Phase ◽  
Inertial Sensors ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Foot Orthoses ◽  
Foot Kinematics ◽  
Running Injuries ◽  
The Right ◽  
Movement Differences

The objectives of this study were to determine the amplitude of movement differences and asymmetries between feet during the stance phase and to evaluate the effects of foot orthoses (FOs) on foot kinematics in the stance phase during running. In total, 40 males were recruited (age: 43.0 ± 13.8 years, weight: 72.0 ± 5.5 kg, height: 175.5 ± 7.0 cm). Participants ran on a running treadmill at 2.5 m/s using their own footwear, with and without the FOs. Two inertial sensors fixed on the instep of each of the participant’s footwear were used. Amplitude of movement along each axis, contact time and number of steps were considered in the analysis. The results indicate that the movement in the sagittal plane is symmetric, but that it is not in the frontal and transverse planes. The right foot displayed more degrees of movement amplitude than the left foot although these differences are only significant in the abduction case. When FOs are used, a decrease in amplitude of movement in the three axes is observed, except for the dorsi-plantar flexion in the left foot and both feet combined. The contact time and the total step time show a significant increase when FOs are used, but the number of steps is not altered, suggesting that FOs do not interfere in running technique. The reduction in the amplitude of movement would indicate that FOs could be used as a preventive tool. The FOs do not influence the asymmetry of the amplitude of movement observed between feet, and this risk factor is maintained. IMU devices are useful tools to detect risk factors related to running injuries. With its use, even more personalized FOs could be manufactured.

scholarly journals Does Consumption of Nitrate Containing Beetroot Juice Affect Indoor Rowing Performance in Males and Females?

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1754-1754
Author(s):  
Giselle Greisman ◽  
June Kloubec ◽  
Alexandra Kazaks ◽  
Kelly Morrow ◽  
Cristen Harris
Keyword(s):  
P Value ◽  
Beetroot Juice ◽  
Double Blind ◽  
Male Athletes ◽  
Funding Sources ◽  
Beverage Type ◽  
Rowing Performance ◽  
Males And Females ◽  
The Difference ◽  
Research Grant

Abstract Objectives The nitrates found in beetroot juice (BR) are known to be a precursor of nitric oxide (NO). NO is a known vasodilator which allows more oxygen to travel in the blood and may improve muscle efficiency. This study aims to measure the effect of BR supplementation on performance on 500-meter row time for trained CrossFit athletes. Many past studies have analyzed the effect of BR on male athletes, this study aimed to include both males and females. Methods This study used a randomized, cross-over, double-blind, placebo-controlled design to measure 500-meter row time. Thirty athletes age 18–60 consumed either a 2.7 oz shot of BR (6.5 mmol nitrate) or a placebo nitrate-free beetroot juice (PL). Two hours later, they rowed 500 meters. After at least a seven-day washout period, athletes repeated the 500-meter row with either BR or PL for comparison. This study was performed from July 2019 – January 2020 and was conducted in Mercer Island, Washington. Results Ten males age 18.0 to 60.3 (median 47.7) and twenty females age 26.7 to 58.3 (median 43.8), participated in this study. Row times for the 500-meter row ranged from 88.2 seconds to 150.7 seconds. Data indicate that although 60% of all participants rowed faster with BR (mean 112.83 seconds), compared to PL (mean 113.40 seconds), the difference in the means of row times (−0.563) was not significant overall (P = 0.29). However, for the 10 males, row times were significantly faster (1.02 second difference, P = 0.04) on average with BR compared to PL. For the 20 females, the difference in mean row time (−0.335 seconds) was not significant (P = 0.66). Competitive rowers were defined as those who rowed under 110 seconds (N = 15). For competitive rowers (10 males, 5 females), row times were significantly faster with BR compared to PL (difference in means −0.94, P = 0.009). However, for those rowers, the P-value of drink * group was 0.015. Conclusions Dietary nitrate improved indoor rowing performance in males but not in females. In addition, competitive rowers were also significantly faster with BR, however, there may be an order bias, since there was significant interaction between beverage type and testing order. Food based nitrate supplements may increase rowing performance with male rowers. Funding Sources Supported by Bastyr Faculty Student Research Grant.

scholarly journals Design of a 2DoF Ankle Exoskeleton with a Polycentric Structure and a Bi-Directional Tendon-Driven Actuator Controlled Using a PID Neural Network

Actuators ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 9
Author(s):  
Taehoon Lee ◽  
Inwoo Kim ◽  
Yoon Su Baek
Keyword(s):  
Neural Network ◽  
Degrees Of Freedom ◽  
Plantar Flexion ◽  
Length Change ◽  
Talocrural Joint ◽  
Lower Limb Exoskeleton ◽  
Exoskeleton Robot ◽  
The Difference ◽  
Ankle Exoskeleton ◽  
The Stability

Lower limb exoskeleton robots help with walking movements through mechanical force, by identifying the wearer’s walking intention. When the exoskeleton robot is lightweight and comfortable to wear, the stability of walking increases, and energy can be used efficiently. However, because it is difficult to implement the complex anatomical movements of the human body, most are designed simply. Due to this, misalignment between the human and robot movement causes the wearer to feel uncomfortable, and the stability of walking is reduced. In this paper, we developed a two degrees of freedom (2DoF) ankle exoskeleton robot with a subtalar joint and a talocrural joint, applying a four-bar linkage to realize the anatomical movement of a simple 1DoF structure mainly used for ankles. However, bidirectional tendon-driven actuators (BTDAs) do not consider the difference in a length change of both cables due to dorsiflexion (DF) and plantar flexion (PF) during walking, causing misalignment. To solve this problem, a BTDA was developed by considering the length change of both cables. Cable-driven actuators and exoskeleton robot systems create uncertainty. Accordingly, adaptive control was performed with a proportional-integral-differential neural network (PIDNN) controller to minimize system uncertainty.

Policy for increasing feeder stock of Bali cattle (Bos javonicus domesticus) in Kupang District

2020 ◽  
Vol 5 (6) ◽  
pp. 235-248
Author(s):  
Maria Krova ◽  
◽  
M. F. Lalus ◽  
Markus M. Kleden ◽  
◽  
...  
Keyword(s):  
Systems Approach ◽  
Population Based ◽  
Supply Management ◽  
Stock Management ◽  
Contributing Factors ◽  
Policy Interventions ◽  
Innovation And Technology ◽  
Calving Rate ◽  
Bali Cattle ◽  
The Difference

The scarcity of feeder stock of Bali cattle (Bos javonicus domesticus) in Kupang Regency is currently increasing. One of the contributing factors is the difference in management between the fattening business that produces beef cattle and the breeding business that produces feeders and heifers. The research aims to determine: the interaction between actors to increase the supply of feeder; the behavior of feeder population based on actual stock management, and the necessary policy interventions to increase the supply of feeder. The research was conducted by applying a dynamics systems approach. This modelling used ventana systems software. Data and mental models were collected through observation, focus group discussions, and in-depth interviews with key informants. The results showed that the interaction between actors was limited to the marketing of cattle for both local and domestic markets. The actual feeders supply management shows that cattle population tends to decline due to low calving rate (70%), high calves mortality (35%), and the high slaughtering of productive females (80%). The necessary policy interventions are to implement various efforts to increase the calving rate to be 80%, reduce the mortality rate by applying 2% feed supplementation, and reduce the sales of productive females to be 50%. The actual supply management of Bali feeders needs to be engineered by increasing stakeholder services that coordinate synergistically for learning innovation and technology. It is necessary to establish a breeder cooperative to suppress the sale of productive cows as the cause of its high slaughtering

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