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1.
The relationship between inappropriate breast support and upper-extremity kinematics for female runners is unclear. The purpose of this study was to investigate the effect of breast support and breast pain on upper-extremity kinematics during running. Eleven female recreational runners with larger breasts (UK D and E cup) completed a 7 min 20 s treadmill run (2.58 m · s?1) in a high and low breast support condition. Multi-planar breast and upper-extremity kinematic data were captured in each breast support condition by eight infrared cameras for 30 s towards the end of the run. Breast pain was rated at the end of each treadmill run using a numeric analogue scale. The high support bra reduced breast kinematics and decreased breast pain (P < 0.05). Upper-extremity kinematics did not differ between breast support conditions (P > 0.05), although some moderate positive correlations were found between thorax range of motion and breast kinematics (r = 0.54 to 0.73). Thorax and arm kinematics do not appear to be influenced by breast support level in female runners with large breasts. A high support bra that offers good multi-planar breast support is recommended for female runners with larger breasts to reduce breast pain. 相似文献
2.
Breast displacement has been investigated in various activities to inform bra design, with the goal of minimising movement; however, breast motion during swimming has yet to be considered. The aim was to investigate trunk and breast kinematics whilst wearing varying levels of breast support during two swimming strokes. Six larger-breasted females swam front crawl and breaststroke (in a swimming flume), in three breast support conditions while three video cameras recorded the motion of the trunk and right breast. Trunk and relative breast kinematics were calculated. Greater breast displacement occurred mediolaterally in the swimsuit condition (7.8, s = 1.5 cm) during front crawl and superioinferiorly in the bare-breasted condition (3.7, s = 1.6 cm) during breaststroke, with the sports bra significantly reducing breast displacements. During front crawl, the greatest trunk roll occurred in the sports bra condition (43.1, s = 8.3°) and during breaststroke greater trunk extension occurred in the swimsuit condition (55.4, s = 5.0°); however, no differences were found in trunk kinematics between the three breast support conditions. Results suggest that the swimsuit was ineffective as a means of additional support for larger-breasted women during swimming; incorporating design features of sports bras into swimsuits may improve the breast support provided. 相似文献
3.
During backstroke, an optimum shoulder entry angle of 180° has been anecdotally suggested; however, this has yet to be investigated biomechanically. The aim of this study was to quantify shoulder entry angles for advanced and intermediate backstroke swimmers. Six advanced (season's best?<150?s) and six intermediate (season's best?>160?s) 200-m backstroke swimmers had markers applied to the medial humeral epicondyles and glenoid cavities. Following a familarization period, participants completed backstroke swimming trials (90?s each) in a swimming flume at 50%, 60%, 70%, and 80% of their season's best 200-m velocity. A camera positioned above the flume recorded frontal plane motion, which was digitized and analysed in Simi Motion Systems. The mean peak angle between the upper arm and the line of progression was established in ten strokes for each participant. The results showed backstroke shoulder entry angles for advanced swimmers (170°) were significantly closer to the suggested optimum 180° compared with those of intermediate swimmers (161°). The non-dominant arm displayed values closer to the optimum (171°), while swimming speed had no effect on backstroke shoulder entry angle. In conclusion, backstroke shoulder entry angle may help discriminate between advanced and intermediate backstroke swimmers and may be influenced by laterality dominance, being independent of swimming speed. 相似文献
4.
Nicola Brown Jennifer White Amanda Brasher Joanna Scurr 《Journal of sports sciences》2013,31(9):801-809
AbstractAlthough it is acknowledged that appropriate breast support during exercise is important, no published literature has assessed breast support usage in a cohort of female marathon runners. This study aimed to identify sport bra use and perceived importance of sports bra use in female marathon runners. Bra satisfaction, incidence of bra related issues and factors that influence the appropriateness of sports bras were also investigated. A 4-part, 30-question survey was administered to 1397 female runners at the 2012 London marathon registration and via an online survey. In total 1285 surveys were completed. Sports bra use and its perceived importance was high, however was lower in moderate compared to vigorous activity, and lower in participants with smaller breasts. Seventy-five per cent of participants reported bra fit issues. The most common issues were chaffing and shoulder straps digging in, with a higher incidence of issues reported by participants with larger breasts. Use of professional bra fitting was low, and perceived knowledge of breast health was poor. Engagement with sports bra use is high although sports bra design could be improved to alleviate bra fit issues experienced by female runners. Educational initiatives are needed to ensure females are informed regarding the importance of breast support and appropriate bra fit during activity. 相似文献
5.
A dynamic model of the breast during exercise 总被引：1，自引：1，他引：0
The aim of this paper is to develop a method to determine the material characteristics of bras that could limit breast motion
during exercise. A single participant ran on a treadmill at 10 km h−1 wearing either a sports bra, an everyday bra or no bra. The relative motion between the suprasternal notch and the breast
was recorded using a passive marker system at 200 Hz and was modelled as forced damped-harmonic motion with a linear spring
and damper, with the driving force provided by the suprasternal notch. The spring and damper values were found by matching
the model to the experimental data. It was found that both the damping and stiffness values increased with the use of an everyday
bra, and increased further still with the use of a sports bra. The stiffness parameter, however, was shown to be the most
important criterion for minimisation of the breast motion. The model predicted that an increase in breast mass from 100 to
700 g (a 32A-cup to a 32F-cup) increased the vertical motion of the unsupported breast by around 70% when running and 30%
when walking. This was reduced with an everyday bra and further reduced with the high stiffness sports bra. Although predictions
were sensible, the model requires further verification with a cohort of participants. 相似文献
6.
Six competitive soccer players were recruited to examine EMG activation in three quadriceps muscles during a kicking accuracy task. Participants performed three maximum instep place kicks of a stationary ball, 11 m perpendicular from the centre of the goal line towards targets (0.75 m(2)) in the four corners of the goal. Surface EMG of the vastus lateralis, vastus medialis, and rectus femoris of the kicking leg was normalized and averaged across all participants to compare between muscles, targets, and the phase of the kick. Although no significant difference were observed between muscles or kick phases, kicks to the right targets produced significantly greater muscle activity than those towards the left targets (P < 0.01). In addition, kicks towards the top right target demonstrated significantly greater muscle activity than towards the top and bottom left (P < 0.01). Under accurate soccer shooting conditions, kicks aimed to the top right corner of the goal demonstrated a higher level of quadriceps muscle activation than those towards the other corners. 相似文献
7.
The purpose of this study was to determine a way of estimating the strain of the breast during exercise and to enable an engineering
analysis of breast motion. Three participants exercised on a treadmill wearing a sports bra, an everyday bra or no bra and
the motion of the body and the nipple were recorded using a 200 Hz passive marker motion capture system. Each participant
also performed a breast drop test to determine the neutral position of the nipple; this allowed strains to be estimated from
the point when nipple acceleration was approximately that due to gravity. Wearing any bra reduced the strain at the nipple
by lifting the breast mass up towards the neutral position where the skin of the breast was neither in tension nor in compression.
Non-linearities in strain occurred during the downward phase of running at strain values exceeding the static value at up
to 70% strain; these were consistent with the previous studies on skin. It was postulated that comfort scores might be related
to elements of the acceleration–strain curve and that nipple motion causing strain beyond static strain might be an important
parameter in understanding breast pain. 相似文献
8.
Appropriate sports bras are crucial to limit potential breast pain and ptosis. In an attempt to optimize breast support during exercise, manufacturers now produce activity level-specific sports bras. However, until breast movement across activity levels is understood, the criterion for such apparel is unknown. Therefore, the aim of this study was to quantify multi-planar breast displacement across treadmill activity levels and breast support conditions. Twenty-one D cup participants had markers attached to their nipples and trunk to calculate relative 3D breast displacement. Supported and unsupported mediolateral, anterioposterior, vertical, and resultant breast displacement was assessed during treadmill walking up to maximum running. Unsupported resultant breast displacement increased from 4.2 ± 1.0 cm during walking to 15.2 ± 4.2 cm during running. There was no change in breast displacement amplitude or direction as running speed increased above 10 km · h?1, with vertical breast displacement then accounting for ～50% of overall displacement. While breast support was effective in reducing the amplitude of breast displacement during walking and running, the direction was unaffected. In conclusion, instead of activity level-specific breast support, future research should identify multi-planar breast kinematics during various sporting modalities. This might lead to production of a sports-specific bra to reduce the negative consequences of breast movement. 相似文献
9.
Literature has established that a range of physiological, biomechanical, and training variables influence marathon performance. The influence of anthropometric characteristics has also received attention. However, despite major marathons exceeding 40,000 participants and approximately a third of these runners being female, no data exist on the influence of the breast on running performance. This cross-sectional study aimed to explore the impact of breast mass on marathon finish time. One hundred and sixty-eight of 321 female marathon runners contacted completed an on-line survey focusing on marathon performance during the 2012 London marathon. Participants were categorised as smaller (<500?g, 54%) or larger breasted (>500?g, 46%). Regression analysis identified that 24% of marathon performance variance could be explained by body mass index (BMI), but breast mass improved the model to explain 28% of performance variation. The model determined that for women with 32/34 or 36/38 underband each increase in cup size equates to a performance decrement of 4.6?min or 8.6 min, equivalent to 34.4?min difference between a woman with 36A compared to 36DD breast size. Larger breasted runners had greater BMIs, completed less marathons and had slower marathon finish times (316?±?48?min) compared to smaller breasted runners (281?±?51?min). Twenty-five per cent less larger breasted women finished in the fastest quartile. These results suggest that differences in breast mass are an important factor for female athletes and should be considered in future research in this area. 相似文献
10.
Teacher expectancies can have an impact on students' academic achievement. These expectancies can be based on diverse student characteristics, only one of which is past academic performance. The present study investigated three student individual differences that teachers may use when forming academic expectancies: the sex of the student, the family socioeconomic status (SES) of the student, and the student's after-school activities. Results indicated teachers held higher grade, graduation, and college attendance expectancies for females than for males and for middle-SES than low-SES students. Also, students who participated in extracurricular activities were expected to achieve more academically than either students who were employed after school or who did nothing after school. The latter two groups did not elicit different teacher expectancies. Interactions revealed that (a) lowest expectations were held for low-SES males who did nothing after school and (b) the difference in graduation expectancies between the SES groups was only half as great for students who took part in extracurricular activities than it was for students who had no involvements after school or who had jobs. Copyright 2000 Academic Press. 相似文献