The aim of this study was to identify the immediate effect of self-modelling with different focus of attention strategies (i.e., internal vs. external) on the teaching/learning of gymnastics ...motor-skills. Fifty-nine non-gymnast students participated in this study and were divided into three groups (i.e., an external focus group (EF), an internal focus group (IF), and a control group (CG)). Each participant’s performance of the back dismount in the parallel bars was assessed before the experiment (i.e., base-score), and each participant was asked to provide a self-evaluation of their performance and their efficiency percentage. Afterwards, participants received a specific learning session (i.e., self-modelling with external focus, self-modelling with internal focus, or traditional learning with verbal instruction) and performed the back dismount in the parallel bars again immediately after (i.e., final score). Four international judges evaluated performance of our participants. The results showed that the EF and IF outperformed the CG in the final score. Importantly, a significant difference between the base and the final score was observed in the EF and IF, but not in the CG. In addition, the EF showed the highest percentage of improvement (Δ-score) and self-estimation scores compared to the two other groups. In conclusion, this study supports the adoption of external focus of attention for teaching/learning gymnastics motor-skills.
After stroke, gait training is a key component of rehabilitation, and most individuals use a variety of walking aids depending on their physical condition and environment.
This study aimed to ...investigate the potential effect of a one-arm motorized gait device for gait assist of chronic hemiplegic stroke survivors through comparison with traditional gait devices (parallel bar and hemi-walker).
This study was conducted on 14 chronic hemiplegic stroke survivors. The participants were asked to walk under three conditions using different gait devices, and their gait parameters during walking were collected and analyzed. The first condition involved walking on parallel bars; second condition, walking using hemi-walkers; and third condition, walking using one-arm motorized gait devices. With the use of a gait analysis system, the spatio-temporal gait parameters in each condition were collected, such as gait velocity, cadence, step length, stride length, single support time, and double support time.
In the results by repeated-measures ANOVA or the Friedman test, a significant difference was found in the gait parameters among all three conditions (p< 0.05). The post-hoc test showed a significant change in the spatio-temporal gait parameters (especially, velocity, cadence and affected side single and double support time) when one-arm motorized gait device were used compared with parallel bars and hemi-walkers (p< 0.05).
The results of this study suggest that one-arm motorized gait devices developed for hemiplegic stroke survivors may be more effective potentially than parallel bars and hemi-walkers in gait assistance of chronic hemiplegic stroke survivors.
In sports and exercise science, thermography is used extensively to evaluate athletic performance, to study exercise-induced superficial vascular changes, and to monitor injuries. There is a lack of ...research and literature on palm temperatures after different loads and our question was how palm temperature differs after static and dynamic loading on the parallel bars since the application is so varied (competitive and recreational sports, physical education, rehabilitation). Thirty-eight students from the Faculty of Sport at the University of Ljubljana were measured using a high-quality thermal imaging camera. Palm temperatures were measured before the load was applied, immediately after the load, and every 30 seconds for a period of 5 minutes after the load. Each hand was divided into nine different regions of interest (ROIs). Mean (XA), standard deviation (SD), maximum and minimum, and number of pixels were calculated. Our study showed that the temperature in the palm decreased immediately after the load, and then began to increase. Within 5 minutes, it reached higher values than before the application of the load, and after swings (dynamic load), the temperature values were higher than after support (static load). Different loads have different effects on the temperature of the hand.
Unusual shore-normal and barred-like rhythmic features were found in Camposoto Beach (Bay of Cádiz, SW Spain) during a monitoring program using unmanned aerial systems (UAS). They appeared in the ...backshore and persisted for 6 months (October 2017–March 2018). Their characteristics and possible formation mechanism were investigated analyzing: (1) UAS-derived high-resolution digital elevation models (DEMs), (2) hydrodynamic conditions, and (3) sediment samples. The results revealed that the features did not migrate spatially, that their wavelength was well predicted by the edge wave theory, and that they shared characteristics with both small-scale low-energy finger bars (e.g., geometry/appearance and amplitude) and swash cusps (e.g., wavelength, seaward circulation pattern, and finer and better sorted material in the runnels with respect to the crests). Our findings pinpoint to highly organized swash able to reach the backshore during spring tides under low-energy and accretionary conditions as well as backwash enhanced by conditions of water-saturated sediment. This study demonstrates that rhythmic features can appear under different modalities and beach locations than the ones observed up to date, and that their unusual nature may be attributed to the low spatiotemporal resolution of the traditional coastal surveying methods in comparison with novel technologies such as UAS.
Epidemiological and laboratory studies indicate that polychlorinated biphenyls (PCBs) and methyl mercury (MeHg) may have additive or interactive adverse effects on nervous system function. Prior ...studies have shown that high doses of MeHg target the cerebellum and impair balance and coordination, but the effects of PCBs on cerebellar function were unknown. In addition, the combined effects of PCBs and MeHg on cerebellar function have not been studied previously. Therefore, we investigated the effects of developmental exposure to PCBs, MeHg, or PCBs + MeHg on three motor tasks that involve cerebellar functions. Female Long-Evans rats were exposed to MeHg (0.5 ppm in drinking water), PCBs (6-mg/kg/d Aroclor 1254), PCBs + MeHg, or vehicle only beginning 4 weeks prior to breeding, through pregnancy, and continuing through postnatal day (PND) 16. Starting at approximately PND 60, one male and one female from each litter were tested on three motor tasks that involve cerebellar function. PCB + MeHg–exposed rats were impaired relative to the controls on a task requiring them to traverse a rotating rod. Rats exposed to PCBs alone were also somewhat impaired relative to the controls, whereas MeHg-exposed rats were not significantly different from the controls. There were no statistically significant deficits related to PCB or MeHg exposure on a vertical rope-climbing test or a parallel bar test. Our results demonstrate that the possibility of additive neurotoxic effects of PCBs and MeHg needs to be seriously considered.
Abstract In a prior study with high level gymnasts we could demonstrate that the neuromuscular activation pattern during the “whip-like” leg acceleration phases (LAP) in accelerating movement ...sequences on high bar, primarily runs in a consecutive succession from the bar (punctum fixum) to the legs (punctum mobile). The current study presents how the neuromuscular activation is represented during movement sequences that immediately follow the LAP by the antagonist muscle chain to generate an effective transfer of momentum for performing specific elements, based on the energy generated by the preceding LAP. Thirteen high level gymnasts were assessed by surface electromyography during high performance elements on high bar and parallel bars. The results show that the neuromuscular succession runs primarily from punctum mobile towards punctum fixum for generating the transfer of momentum. Additionally, further principles of neuromuscular interactions between the anterior and posterior muscle chain during such movement sequences are presented. The findings complement the understanding of neuromuscular activation patterns during rotational movements around fixed axes and will help to form the basis of more direct and better teaching methods regarding earlier optimization and facilitation of the motor learning process concerning fundamental movement requirements.
The purpose of this study was to examine one of the factors needed for mastering Backward uprise and 5/4salto forward straggled to up hang (Japaner salto upper to hang) by exploring the technical ...differences between perspective of morphology of movement. A total of 4 people were selected, 2 each for those who have learned and those who have not. Two gymnasts already mastered were that they performed quickly “nuki” and “ahuri” in the preparation phase and rotation while backward in the direction of motion 5/4salto forward phase. These results suggest that it is a useful technique.
평행봉 몸 접고 2회전 뒤 공중 돌아 내리기 동작 평가 송주호; Song Joo Ho; 박종철 ...
Ch'eyuk kwahak yŏn'gu,
06/2014, Letnik:
25, Številka:
2
Journal Article
이 연구는 평행봉 몸 접고 2회전 뒤 공중 돌아내리기 동작의 정량적 분석과 정성적 분석을 통해 개인별 문제점과 기술 개선을 위한 피드백을 제공함으로써 동작의 완성도를 높이고자 하였다. 분석을 통한 피드백을 제공 내용은 다음과 같다. KHH는 릴리스 타이밍이 빨라 회전속도의 감속에 문제가 발생한 것으로 나타났다. NYI는 릴리스 시 좌측으로 밀어주지 못하고 ...동체 회전이 크게 나타나 중심이 후방으로 빠지는 동작을 나타내 공중회전 시 손의 위치 교정 등을 통해 ‘V자’ 자세를 만들 수 있도록 노력해야 한다. RSD는 회전이 부족한 상태로 착지하는 것으로 나타났는데, 2구간에서 평행봉의 탄성을 이용할 수 있는 훈련 및 손의 위치 등의 교정이 필요한 것으로 나타났다. PMS는 착지구간에서도 지속적으로 동체회전각속도가 증가하고 있어 불안정한 착지가 발생하고 있으며 체공 높이 확보를 위한 훈련이 요구된다. PEJ는 릴리스 시 신체중심 수직위치가 높아 체공 높이에 긍정적인 영향을 미치며 이상적인 ‘V자’자세를 취하며 공중회전이 이루어진 것으로 나타나 비교적 안정된 착지자세를 취한 것으로 나타났다. BGR는 신체중심 수직위치가 높아 체공 높이에 긍정적인 영향을 미칠 뿐만 아니라 이상적인 ‘V자’ 자세를 취하며 공중회전이 이루어진 것으로 나타나 가장 안정된 착지자세로 이어진 것으로 나타났다. YHS은 릴리스 순간 수평보다는 수직방향으로 밀어야 체공 높이에 긍정적 영향을 미칠 것이며, 특히 공중회전 시 손의 위치도 대퇴부분이 아닌 무릎 뒤쪽을 잡아야 ‘V자’ 자세를 보다 효과적으로 취할 수 있을 것이다. CJY는 고관절각이 릴리스 순간 가장 작게 나타나면서 수직 상승을 위한 자세를 취하지 못했으며, 무릎관절 각이 가장 작게 나타나 신전시키지 못한 상태로 회전과 착지 동작을 수행하는 것으로 나타났다.
The purpose of this study was to identify the characteristics through technical analysis of dismount to perform the successful landing. The subjects in this study were male gymnastic players of the national team, hish-speed cameras were used to record the salto backward dismount on the parallel bars of the subjects and to study the qualitative and quantitative analysis. The evaluations including feedback of each subjects’problem were as follow: KHH showed early release timing compared to other players. It could be one of factors which can not decelerating the rotational speed, so the correction of posture is needed. NYI didn’t slide to the left at the release phase, and showed big rotation of body compared to other players so the center of mass moved to the rear. The correction of the hand position at flight phase is necessary to perform the V-shaped position. RSD landed in a state where the rotation is insufficient, so the training using elasticity of parallel bars at phase 2, and the correction of hand position are in need. PMS’s rotation angular velocity of body increased consistently, so showed instable land. Therefore the training to ensure the height of flight is required. PEJ showed high vertical position of CM at the release phase which is help for height of flight. He performed ideal V-shaped position, and took a relatively stable landing position. BGR also showed high vertical position of CM and performed ideal V-shaped position, so he landed in a posture in which the most stable. YHS should push vertically rather than horizontally at the moment of release. Especially, the hand position is not on the hamstring but on the back of the knee to perform the ideal V-shaped position. CJY showed little hip angle at the release phase, so he can’t take a position for vertical rise. Also he showed the lowest knee angle and performed rotation and landing in a state that cannot extend the knee. If such problems are corrected, it will be helpful to landing position not only in parallel bars but also in other events.
The undersomersault, or felge, to handstand on parallel bars has become an important skill in Men's Artistic Gymnastics as it forms the basis of many complex variations. To receive no deductions from ...the judges, the undersomersault must be performed without demonstrating the use of strength to achieve the final handstand position. Two male gymnasts each performed nine undersomersaults from handstand to handstand while data were recorded using an automatic motion capture system. The highest and lowest scoring trials of each gymnast, as determined by four international judges, were chosen for further analysis. Three optimization criteria were used to generate undersomersault technique during the swing phase of the skill using a computer simulation model: minimization of peak joint torques, minimization of horizontal velocity before release, and maximization of angular momentum. The techniques used by both gymnasts could be explained using the second optimization criterion which facilitated further skill development. The first optimization criterion generated a technique advocated for beginners where strength might be expected to be a limiting factor. The third optimization criterion resulted in a different type of undersomersault movement of greater difficulty according to the FIG Code of Points.
Abstract Forward dynamics simulations of a dismount preparation swing on the uneven parallel bars were optimized to investigate the sensitivity of dismount revolution potential to the maximum bar ...force before slipping, and to low-bar avoidance. All optimization constraints were classified as 1-anatomical/physiological; limiting maximum hand force on the high bar before slipping, joint ranges of motion and maximum torques, muscle activation/deactivation timing and 2-geometric; avoiding low-bar contact, and requiring minimum landing distance. The gymnast model included torso/head, arm and two leg segments connected by a planar rotating, compliant shoulder and frictionless ball-and-socket hip joints. Maximum shoulder and hip torques were measured as functions of joint angle and angular velocity. Motions were driven by scaling maximum torques by a joint torque activation function of time which approximated the average activation of all muscles crossing the joint causing extension/flexion, or adduction/abduction. Ten joint torque activation values, and bar release times were optimized to maximize dismount revolutions using the downhill simplex method. Low-bar avoidance and maximum bar-force constraints are necessary because they reduce dismount revolution potential. Compared with the no low-bar performance, optimally avoiding the low bar by piking and straddling (abducting) the hips reduces dismount revolutions by 1.8%. Using previously reported experimentally measured peak uneven bar-force values of 3.6 and 4.0 body weight (BW) as optimization constraints, 1.40 and 1.55 revolutions with the body extended and arms overhead were possible, respectively. The bar-force constraint is not active if larger than 6.9 BW, and instead performances are limited only by maximum shoulder and hip torques. Bar forces accelerate the mass center (CM) when performing muscular work to flex/extend the joints, and increase gymnast mechanical energy. Therefore, the bar-force constraint inherently limits performance by limiting the ability to do work and reducing system energy at bar release.
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