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1.
We have performed a study on the thermo-formation process of plastic shells of boots for winter sports. The aim of the work has been to determine how the process parameters can improve the ergonomic and thermal comfort for athletes and winter sports participants. We have found that the initial deformation and memory effect are strongly influenced by the type of thermoplastic material used, heating time and cooling procedure. We have also found that the ovens currently used for this process are not correctly designed to obtain an efficient heat transfer and, therefore, a heating time of at least 12 min is necessary to achieve an average deformation of more than 2 mm. The measure of the boot flexural stiffness has shown that there are no changes in the load–deflection behavior after the thermo-formation process of a ski boot made of thermoplastic polyurethane. We have also found that the thermo-formation process decreases the pressure on skier’s feet of more than five times and, therefore, improves the comfort of the skier.  相似文献   

2.
An articulated boot design is commonly used in skiing and skating sports because it allows sagittal plane ankle mobility while still providing critical frontal plane stability. Although articulated boots have been in use for several decades, current manufacturers of these boots differ in their articulation placement. In this study we determined an optimal position of the ankle articulation axis. We also calculated the amount of anterior skin movement that a boot tongue must account for during a full range of ankle motion. Three-dimensional kinematic data were collected and analyzed from 40 participants moving their right foot through a full range of sagittal plane motion. The calculated horizontal position of the articulation axis was found to be highly predictable from foot length (r = 0.87, standard error of estimate = 3.44 mm), while its vertical component displayed less predictability (r = 0.49, standard error of estimate = 7.46 mm). The expansion required by the boot tongue had a moderate association with foot length and low variability (r = 0.58, standard error of estimate = 0.07 mm). An accurate axis placement will minimize relative motion between the boot cuff and the ankle, reducing friction and motion resistance. An expandable tongue will accommodate full plantar flexion and reduce pressure on the anterior ankle during dorsiflexion, eliminating common pressure-related injuries.  相似文献   

3.
Skiing‐Skating     
An articulated boot design is commonly used in skiing and skating sports because it allows sagittal plane ankle mobility while still providing critical frontal plane stability. Although articulated boots have been in use for several decades, current manufacturers of these boots differ in their articulation placement. In this study we determined an optimal position of the ankle articulation axis. We also calculated the amount of anterior skin movement that a boot tongue must account for during a full range of ankle motion. Three‐dimensional kinematic data were collected and analyzed from 40 participants moving their right foot through a full range of sagittal plane motion. The calculated horizontal position of the articulation axis was found to be highly predictable from foot length (r = 0.87, standard error of estimate = 3.44 mm), while its vertical component displayed less predictability (r = 0.49, standard error of estimate = 7.46 mm). The expansion required by the boot tongue had a moderate association with foot length and low variability (r = 0.58, standard error of estimate = 0.07 mm). An accurate axis placement will minimize relative motion between the boot cuff and the ankle, reducing friction and motion resistance. An expandable tongue will accommodate full plantar flexion and reduce pressure on the anterior ankle during dorsiflexion, eliminating common pressure‐related injuries.  相似文献   

4.
Plantar loading may influence comfort, performance and injury risk in soccer boots. This study investigated the effect of cleat configuration and insole cushioning levels on perception of comfort and in-shoe plantar pressures at the heel and fifth metatarsal head region. Nine soccer academy players (age 15.7 ± 1.6 years; height 1.80 ± 0.40 m; body mass 71.9 ± 6.1 kg) took part in the study. Two boot models (8 and 6 cleats) and two insoles (Poron and Poron/gel) provided four footwear combinations assessed using pressure insoles during running and 180° turning. Mechanical and comfort perception tests differentiated boot and insole conditions. During biomechanical testing, the Poron insole generally provided lower peak pressures than the Poron/gel insole, particularly during the braking step of the turn. The boot model did not independently influence peak pressures at the fifth metatarsal, and had minimal influence on heel loads. Specific boot-insole combinations performed differently (P < 0.05). The 8-cleat boot and the Poron insole performed best biomechanically and perceptually, but the combined condition did not. Inclusion of kinematic data and improved control of the turning technique are recommended to strengthen future research. The mechanical, perception and biomechanical results highlight the need for a multi-faceted approach in the assessment of footwear.  相似文献   

5.
A common anterior cruciate ligament (ACL) injury situation in alpine ski racing is landing back-weighted after a jump. Simulated back-weighted landing situations showed higher ACL-injury risk for increasing ski boot rear stiffness (SBRS) without considering muscles. It is well known that muscle forces affect ACL tensile forces during landing. The purpose of this study is to investigate the effect of different SBRS on the maximal ACL tensile forces during injury prone landings considering muscle forces by a two-dimensional musculoskeletal simulation model. Injury prone situations for ACL-injuries were generated by the musculoskeletal simulation model using measured kinematics of a non-injury situation and the method of Monte Carlo simulation. Subsequently, the SBRS was varied for injury prone landings. The maximal ACL tensile forces and contributing factors to the ACL forces were compared for the different SBRS. In the injury prone landings the maximal ACL tensile forces increased with increasing SBRS. It was found that the higher maximal ACL force was caused by higher forces acting on the tibia by the boot and by higher quadriceps muscle forces both due to the higher SBRS. Practical experience suggested that the reduction of SBRS is not accepted by ski racers due to performance reasons. Thus, preventive measures may concentrate on the reduction of the quadriceps muscle force during impact.  相似文献   

6.
The robust design of the mass-produced British football boot from the late nineteenth century onwards appeared to evolve rather slowly compared with subsequent lightweight, flexible ‘continental’ fabrication. However, with careful reading we can identify considerable overlap and influence between manufacturers, distributors and retailers. Boot and shoe manufacturing was an intensely competitive industry and it was in the interests of entrepreneurs to pioneer advances in order to promote a particular brand. In developing football boots for the mass market this may have included much pseudo-science but even small innovations sought to improve performance and market share. Design ambiguities were also inherent because footwear manufacturers routinely borrowed and appropriated successful design elements for their own products. With more choice and consumer demand, football boots became increasingly less adapted from other outdoor footwear owned by the participant, to specialised models manufactured as part of the flourishing sporting goods industry. The internationalisation of the mass market for football boots is here explored though the distinct but related case studies of two family firms; Manfield from Northamptonshire, England and Adidas from Herzogenaurach, Germany. Arguing that there was much continuity between the designs and manufacturing processes of the two firms, the article explores how the design of the football boot became increasingly influenced by the fashion industry as items of conspicuous consumption. By 1954 the launch of the training shoe saw sportswear become a style trend worn on the street, rather than on the pitch. This in turn, influenced football boot design as both a highly technical item of elite sportswear and an expensive, aspirational essential in an everyday kitbag.  相似文献   

7.
Touch/control football boots are reportedly designed for optimal passing and dribbling. Little research exists on the effect of boot design on touch/control performance and no validated protocol has been developed for assessing passing and dribbling from an equipment focus. This study aimed to assess the effect of upper padding on dribbling and passing performance using a test–retest reliable test setup. Eight university players performed a protocol of dribbling, short and long passing in football boots with 0 and 6 mm of upper padding (Poron foam). The protocol was completed twice; the 0-mm padding results were used for test–retest validation, while the 0-mm versus 6-mm padding results were used to investigate the effect of padding. Dribbling performance was assessed though completion time, number of touches applied and lateral deviation from cones and passing performance through ball velocity and offset from target. The protocol demonstrated good test–retest reliability and indicated no significant differences in any of the 12 performance variables between the 0- and 6-mm padded boots. These findings suggest an element of design freedom in the use of padding within football boot uppers without affecting dribbling or passing performance.  相似文献   

8.
Due to its associated injury risk, rotational traction is a frequently measured natural turf surface property. The most commonly used equipment, the studded boot apparatus (SBA), consists of a circular stud configuration that does not replicate the stud pattern on a regular football boot and may under or over estimate the surface traction. The aim of this study was to establish potential differences in the rotational traction measured between the current stud configuration on the SBA and the stud configuration on the most commonly used Australian football boots. The original studded boot had significantly higher rotational traction than the moulded stud sole or bladed sole. Location, quality and time tested all interacted significantly with the rotational traction measured. The current SBA may not accurately represent the rotational traction experienced by football players, and consequently may not be the most appropriate configuration to assess the relationship between rotational traction and injuries.  相似文献   

9.
BackgroundShort-leg walking boots are a common intervention for acute and chronic lower extremity injury. Few studies have examined the neuromuscular adaptations associated with short-leg walking boots and no previous study has investigated timing characteristics of muscle activation during gait. The purpose of the current study was to examine the timing and amplitudes of muscle activation of the extrinsic ankle musculature during walking in two types of short-leg walking boots.MethodsEleven healthy young adults performed five level walking trials at a self-selected pace in each of three conditions: normal walking, Gait Walker and Equalizer short-leg walking boots. Ground reaction forces were collected from a force platform while surface electromyography (EMG) was collected from the tibialis anterior, peroneus longus and medial gastrocnemius. EMG signals were rectified and smoothed using the root mean squared with a 20-ms smoothing window and were normalized to the largest mean of the normal walking trials. A repeated measures analysis of variance was used to assess the effect of short-leg walking boots on the onset, duration and amplitude of muscle activation.ResultsShort-leg walking boots were generally associated with earlier onsets of muscle activation and longer durations of muscle activation. However, there was no reduction in EMG amplitude.ConclusionThe findings of this study show that the induced alterations in muscle activation patterns may limit the short-leg walking boots.  相似文献   

10.
This review study focuses on knee injuries in recreational alpine skiing. The objectives of this study were (1) to provide selected knowledge derived from current and past knee injury epidemiology; (2) to outline the most important knee injury mechanisms; and (3) to review and discuss how modifications of the skiing equipment might alleviate the risk of knee injuries. This review represents the essence of a comprehensive research report and considers the content of more than 230 scientific papers, further “grey literature”, patents, international standards and other publications. Knee injuries are the most frequent injuries in alpine skiing and their incidence rate remained high despite a decline of the incidence of other skiing injuries in recent years. Women have a higher knee injury risk, but age and tiredness appear not to be significant factors. Apart from the commonly described injury mechanisms “phantom foot” and “boot-induced anterior drawer” other more sophisticated injury categorisations are given. The ski radius, the ski length and the standing height on the ski may be relevant ski parameters. For the binding, the release mechanisms in different mechanical degrees of freedom, the impact tolerance and the maintenance frequency are discussed. In the ski boot, the height of the upper, the boot liner, the shaft stiffness, and the position on the ski may play a role. The biggest challenge, but probably also the biggest opportunity for a reduction of knee injury rates seems to be the development of a mechatronic binding. The current strategies to develop these types of bindings are explained and illustrated by one example. Some of the possible parameters which may be essential for the necessary control algorithms are described. Finally, considerations regarding the strategic and operational implication of the analysed technical measures are given.  相似文献   

11.
李野 《冰雪运动》2013,(5):70-72
高校开展高山滑雪教学对培养大学生滑雪的兴趣、爱好,以及锻炼行的养成,达到娱乐与健身的目的具有重要作用。由于高校缺乏统一的高山滑雪教材,对开设的滑雪初级教学中存在的一些问题未能寞现有效的共性认识,严重制约了滑雪运动在高校的普及与发展。提出在高山滑雪初级教学中应注意使大学生了解高山滑雪板的结构与性能,学会选用不同类型的高山滑雪板;选择合适的高山滑雪鞋与固定器,固定器的强度要求指标控制在4～5kg为好;高山滑雪服与滑雪杖的选用时注重性价比等问题,探索提高冬季高山滑雪教学质量之策。  相似文献   

12.
In this study, we measured the vertical and horizontal take-off forces, plantar pressures and activation patterns of four muscles (vastus lateralis, gluteus maximus, tibialis anterior, gastrocnemius) in 10 ski jumpers in simulated laboratory conditions when wearing either training shoes or ski jumping boots. We found significant differences in vertical (P < 0.001), horizontal (P < 0.05) and resultant (P < 0.001) take-off velocities and vertical force impulse (P < 0.01). We found no significant differences in the jumpers' initial take-off positions; however, the jumping boots condition resulted in a smaller displacement in the final position of the following joint angles: ankle angle (P < 0.001), knee angle (P < 0.001), hip angle (P < 0.01) and shank angle relative to the horizontal (P < 0.01). This corresponds with less electromyographic activity during take-off in both the gastrocnemius (300 to 200 ms and 200 to 100 ms before take-off) and gluteus maximus (300 to 200 ms and 100 to 0 ms before take-off). During the early take-off in the jumping boots condition, significantly more pressure was recorded under the heel (P < 0.001), whereas the forefoot was more highly loaded at the end of the take-off. Differences in take-off velocity (representing the final output of the take-off) can be accounted for in the main by the different use of plantar flexion, emphasizing the role of the knee and hip extensors when wearing jumping boots. We conclude that the stiffness of the structure of the jumping boots may result in a forward shift of pressure, thus limiting the effective vertical force. To avoid this pressure shift, the pattern of movement of simulated take-offs should be carefully controlled, particularly when wearing training shoes.  相似文献   

13.
In this study, we measured the vertical and horizontal take-off forces, plantar pressures and activation patterns of four muscles (vastus lateralis, gluteus maximus, tibialis anterior, gastrocnemius) in 10 ski jumpers in simulated laboratory conditions when wearing either training shoes or ski jumping boots. We found significant differences in vertical ( P ? 0.001), horizontal ( P ? 0.05) and resultant ( P ? 0.001) take-off velocities and vertical force impulse ( P ? 0.01). We found no significant differences in the jumpers' initial take-off positions; however, the jumping boots condition resulted in a smaller displacement in the final position of the following joint angles: ankle angle ( P ? 0.001), knee angle ( P ? 0.001), hip angle ( P ? 0.01) and shank angle relative to the horizontal ( P ? 0.01). This corresponds with less electromyographic activity during take-off in both the gastrocnemius (300 to 200 ms and 200 to 100 ms before take-off) and gluteus maximus (300 to 200 ms and 100 to 0 ms before take-off). During the early take-off in the jumping boots condition, significantly more pressure was recorded under the heel ( P ? 0.001), whereas the forefoot was more highly loaded at the end of the take-off. Differences in take-off velocity (representing the final output of the take-off) can be accounted for in the main by the different use of plantar flexion, emphasizing the role of the knee and hip extensors when wearing jumping boots. We conclude that the stiffness of the structure of the jumping boots may result in a forward shift of pressure, thus limiting the effective vertical force. To avoid this pressure shift, the pattern of movement of simulated take-offs should be carefully controlled, particularly when wearing training shoes.  相似文献   

14.
Despite proprietary algorithms to account for differences, output from activity trackers worn on different wrists may not be comparable because individuals vary in their reliance on each hand during free-living activities.

Participants (n = 48) wore Fitbit Flex or Flex2 monitors on each wrist for three days. T tests, equivalence tests, and correlations were used to compare steps, Calories, distance, active minutes, and sleep duration recorded by dominant and nondominant wrist-worn monitors and effect sizes and mean absolute and percent difference were calculated.

The nondominant Flex2 monitor was not equivalent to the dominant wrist-worn monitor and recorded significantly more steps/day (absolute difference = 708), miles/day (0.3), and active minutes/day (7.9) than the dominant Flex2 monitor. For all variables, nondominant and dominant output was correlated (r>0.75).

Nondominant and dominant Flex2 monitors are significantly different, but there were small differences for Flex monitors. Research should investigate effects on behavior and replicate findings using other monitors.  相似文献   


15.
Since footwear flexibility impacts functional design factors, numerous studies have investigated footwear bending stiffness. However, the various methods used to measure footwear bending stiffness have some limitations. Hence, the scope of this study was to develop and quantify the reliability of a novel test set-up for measuring footwear bending stiffness. A test set-up consisting of a hydraulic testing machine, a bending apparatus and a fixation unit was created that fulfilled the requirements specified in the initial phase of the study. The test set-up was evaluated by testing 15 different boots in three series of measurements. Bending stiffness of the boots ranged from 0.61 ± 0.03 to 2.38 ± 0.08 Nm/°. Two-way analysis of variance test yielded that the test set-up enabled the reliable measurement of footwear bending stiffness. Relative measurement uncertainty ranged from 1.3 to 6.1 %.  相似文献   

16.
Comfort has been shown to be the most desired football boot feature by players. Previous studies have shown discomfort to be related to increased plantar pressures for running shoes which, in some foot regions, has been suggested to be a causative factor in overuse injuries. This study examined the correlation between subjective comfort data and objective plantar pressure for football boots during football-specific drills. Eight male university football players were tested. Plantar pressure data were collected during four football-specific movements for each of three different football boots. The global and local peak pressures based on a nine-sectioned foot map were compared to subjective comfort measures recorded using a visual analogue scale for global discomfort and a discomfort foot map for local discomfort. A weak (rs = ?0.126) yet significant (P < 0.05) correlation was shown between the peak plantar pressure experienced and the visual analogue scale rated comfort. The model only significantly predicted (P > 0.001) the outcome for two (medial and lateral forefoot) of the nine foot regions. Subjective comfort data is therefore not a reliable measure of increased plantar pressures for any foot region. The use of plantar pressure measures is therefore needed to optimise injury prevention when designing studded footwear.  相似文献   

17.
There are differences in ground reaction force when wearing soccer boots compared with training shoes on a natural turf surface. Two natural-turf-covered force platforms, located outdoors in a field, allowed comparison of performance when six-studded soccer boots and soccer training shoes were worn during straight fast running (5.4 m s-1 ± 0.27 m s-1) and slow running (4.4 ms-1 ± 0.22 m s-1). Six male soccer players (mean age: 25 ± 4.18 years; mean mass 79.7 ±9.32 kg) struck the first platform with the right foot and the second platform with the left foot. In fast running, the mean vertical impact peak was significantly greater in soccer boots (2.706 BW) than in training shoes (2.496 BW) when both the right and left foot were considered together and averaged (P = 0.003). Similarly, the mean vertical impact peak loading rate was greater when wearing soccer boots at 26.09 BWs-1 compared to training shoes (21.32 BWs-1;P = 0.002). Notably, the mean vertical impact peak loading rate of the left foot (boots: 28.07 BWs-1; shoes: 22.52 BWs-1) was significantly greater than the right foot (boots: 24.11 BWs-1; shoes: 20.11 BWs-1) in both boots and shoes (P = 0.018). The braking force was greater for the left foot (P = 0.013). In contrast, mean peak vertical propulsion forces were greater for the right foot (P > 0.001) when either soccer boots or training shoes were considered. Similar significant trends were evident in slow running, and, notably, in both soccer boots and training shoes medial forces were greater for the left foot (P = 0.008) and lateral forces greater for the right foot (P = 0.011). This study showed the natural turf ground reaction force measurement system can highlight differences in footwear in an ecological environment. Greater forces and impact loading rates occurred during running activity in soccer boots than in training shoes, with soccer boots showing reduced shock attenuation at impact. Such findings may have implications for impact-related injuries with sustained exposure, especially on harder natural-turf surfaces. There were differences in the forces occurring at the right and left feet with the ground, thus suggesting the use of bipedal monitoring of ground reaction forces.  相似文献   

18.
肌肉力量测量方法   总被引：40，自引：3，他引：37  
文章首先简要地介绍和讨论了与肌肉力量测量方法有密切关系和应该明确的几个基本问题,即关于肌肉收缩的五种基本形式,关于国际上肌肉力量分类的研究结果,关于绝对力量、最大力量、快速力量、起动力量、爆发力量、反应力量、力量耐力等定义。然后,介绍了用于肌肉力量测量的实验室和运动场测量方法。其中,就基本测量指标、基本测量仪器、基本测量要求和注意事项、各种仪器和测量方法的优点及主要不足等进行了探讨。最后,提出了有关肌肉力量训练水平的检查与评定的基本设想。  相似文献   

19.
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20.
Football shin guards were evaluated against a kick from a studded boot.The bending stiffness of their shells, and their response when impacted by a stud, were assessed using finite element analysis (FEA) and determined experimentally.A test rig was constructed with the leg muscle simulated by flexible foam, with the force distribution along the tibia and to the lateral muscle measured using flexible force sensors.High-speed photography confirmed deformation mechanisms predicted by FEA.Load spreading from the stud impact site correlated with the guard shell bending stiffness.The best guards use shells of complex shape to increase their transverse bending stiffness.  相似文献   

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