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Sports bra but not sports footwear decreases breast movement during walking and running
Abstract
Running is a modality that has a large number of adepts, including women. Therefore, it is important to understand how sportswear can help women, with special attention to the breast movement. The aim of this study was to analyse the effect of different combinations of breast support and footwear on the breast movement during walking and running. Twenty women performed treadmill walking (5 km/h) and running (7 and 10 km/h) combining different footwear (barefoot, minimalist, and traditional) and breast support conditions (bare breast, everyday bra, and sports bra). Three-dimensional data from breast and trunk markers were tracked for 10 stride cycles. Relative breast displacement was calculated and derived for velocity. An interaction effect was observed between support, footwear, and speed conditions. The bare breast conditions presented differences from the other conditions in the majority of the kinematic variables, presenting higher breast displacement and velocity values. On the other hand, the sports bra conditions presented the lowest values for the kinematics variables. In the vertical component of breast displacement during running (10 km/h) we verified that the sports bra presented reductions of 56% and 43% in relation to the bare breast and everyday bra conditions, respectively. Despite this, no differences were found between footwear within each breast support condition. A sports bra is efficient to decrease breast movement. In addition, neither of the tested footwear was able to decrease these movements.
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The main objective of the present study is the use of known statistical methods to overcome the problems in the data and the comparison between them and also to discover the best method and apply it on factual data. This represents the influence of time on children weights, to do that the study considered taking four measurements of weights; they are (the weight in the first month, the weight in the third month, the weight in sixth month, and the weight in the ninth month) from which is one of the governmental health centers in Najaf governorate. The data have been analyzed with different methods including the (Classical) method which represents (Linear Regression Model) and the (Robust Method). Outliers were added to the factual data then analyzed again with the same abovementioned methods. To find out which of the two methods is the best, a comparison has been conducted in which different measurements are used, and they are: Mean Square Error (MSE), Coefficient of Determination (R2), and (P-Value). The comparison showed that Linear Regression Model is better that Robust Model in case of factual data free of outliers, whereas the Robust Model is found to be better than Linear Regression Model in case of factual data with outliers.
Study Design Prospective cohort study. Background The popularity of running events is still growing, particularly among women, however little is known about the risk factors for running-related injuries in female runners. Objectives The aims of this study were to determine the incidence and characteristics (site and recurrence) of running-related injuries and to identify specific risk factors for running-related injuries among female runners training for a 5- or 10-km race. Methods 435 women registered for the Marikenloop run of 5- or 10-km were recruited. Follow-up was conducted over 12 weeks using questionnaires, completed from 8 weeks before to 4 weeks after the event. Two orthopedic tests (navicular drop test and extension of the first metatarsophalangeal joint) were performed in the 8 weeks period before the event. Running-related injuries, defined as running-related pain of the lower back and/or the lower extremity that restricted running for at least 1 day, were assessed at 1, 2 and 3 months follow-up. Results Of 417 female runners with follow-up data (96%), 93 runners (22.3%) reported 109 running-related injuries, mainly of the hip/groin, knee, and lower leg. Multivariable Cox regression analysis showed that a weekly training distance of more than 30 km (HR 3.28; 95% CI 1.23- 8.75) and a previous running injury longer than 12 months ago (HR 1.88; 95% 1.03- 3.45) were associated with the occurrence of running-related injuries. Conclusion Hip/groin, knee and lower leg injuries were common among female runners. Only weekly training distance (> 30 km) and previous running injury (> 12 months) were associated with running-related injuries in female runners training for a 5- or 10-km event. Level of Evidence Etiology 2b. J Orthop Sports Phys Ther, Epub 26 Apr 2016. doi:10.2519/jospt.2016.6402.
The buoyant forces of water during aquatic exercise may provide a form of ‘natural’ breast support and help to minimise breast motion and alleviate exercise induced breast pain. Six larger-breasted females performed standing vertical land and water-based jumps, whilst wearing three breast support conditions. Underwater video cameras recorded the motion of the trunk and right breast. Trunk and relative breast kinematics were calculated as well as exercised induced breast pain scores. Key results showed that the swimsuit and sports bra were able to significantly reduce superioinferior breast range of motion by 0.04 and 0.05 m, respectively, and peak velocity by 0.23 and 0.33 m/s, respectively, during land-based jumping when compared to the bare-breasted condition, but were ineffective at reducing breast kinematics during water-based jumping. Furthermore, the magnitude of swimsuit superioinferior breast range of motion during water-based jumping was significantly greater than land-based jumping (0.13 m and 0.06 m), yet there were no significant differences in exercise induced breast pain, thus contradicting previously published relationships between these parameters on land. Furthermore, the addition of an external breast support garment was able to reduce breast kinematics on land but not in water, suggesting the swimsuit and sports bras were ineffective and improvements in swimwear breast support garments may help to reduce excessive breast motion during aqua aerobic jumping exercises.
Abstract Although 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.
This paper identifies the effective design features of commercial sports bras by evaluating the reduction of breast displacement during activities. Four subjects, with breast and body types representative of Chinese females of age 24–40 years were studied while they performed activities either braless or wearing one of seven different sports bras representative of the range commercially available. The three-dimensional movement of the breasts was derived by videoing the motion of breast markers attached at six different breast positions using a Vicon 3D motion analysis system. The breast displacement relative to the thorax was measured using a validated local “thorax–breast 3D coordinate system”. The results showed that there was a significant difference in breast displacement between the different breast markers. The bra samples generally achieved the greatest reduction in breast displacement in the medial–lateral direction. The reduction in breast displacement was positively related to the gore height, shoulder strap width, neckline height and side seam depth. The underlying mechanism of breast movement and bra support is also discussed. The study concluded that the most effective bras had the following features: compression type, short vest style, high neckline, slings, cross back, bound neckline, no centre gore, no wire, no cradle, no pad and a non-adjustable wide strap. This provides practical guidelines for bra designers and manufacturers to develop more supportive bras for women performing these physical activities.
There is exponentially increasing number of research publications studying breast motion in sports bras. However, there are large varieties of their methods and findings. To critically evaluate the consistency and limitations of previous breast motion studies, a systematic review of all articles on breast motion in sports bras was performed. A total of 17 fully extracted studies included 216 subjects, aged from 20 to 60 with bra cup sizes from A to J. They participated in only four types of activities with or without bras, but not in randomized controlled trials. Most studies focused on the vertical nipple movements, but seldom examined the three-dimensional breast velocity, acceleration, and trajectory. The sample sizes and the types of activities were limited. The reference frames were not stable in most studies. To study the realistic breast movements in the future, a standardized local coordinate system will be needed.
Barefoot running has become a popular research topic, driven by the increasing prescription of barefoot running as a means of reducing injury risk. Proponents of barefoot running cite evolutionary theories that long-distance running ability was crucial for human survival, and proof of the benefits of natural running. Subsequently, runners have been advised to run barefoot as a treatment mode for injuries, strength and conditioning. The body of literature examining the mechanical, structural, clinical and performance implications of barefoot running is still in its infancy. Recent research has found significant differences associated with barefoot running relative to shod running, and these differences have been associated with factors that are thought to contribute to injury and performance. Crucially, long-term prospective studies have yet to be conducted and the link between barefoot running and injury or performance remains tenuous and speculative. The injury prevention potential of barefoot running is further complicated by the complexity of injury aetiology, with no single factor having been identified as causative for the most common running injuries. The aim of the present review was to critically evaluate the theory and evidence for barefoot running, drawing on both collected evidence as well as literature that have been used to argue in favour of barefoot running. We describe the factors driving the prescription of barefoot running, examine which of these factors may have merit, what the collected evidence suggests about the suitability of barefoot running for its purported uses and describe the necessary future research to confirm or refute the barefoot running hypotheses.
Increased impact characteristics are often cited as a cause of running injuries. One method that has been used to reduce impact characteristics is to increase the thickness of the midsole of running footwear with the intention of attenuating greater shock from the foot-ground collision. A second method that has been suggested is to run barefoot. The purpose of this study was to compare the impact characteristics of running footwear of different midsole thickness to a barefoot condition. Three-dimensional kinematic and kinetic data were collected as participants ran at their preferred running speed and at a fixed speed. Impact characteristics (impact peak, time to impact peak and vertical loading rate) were derived from the vertical ground reaction force component. Ankle and knee joint stiffness during the loading phase of support were derived from the change in moment divided by the change in angle. The impact parameters were statistically analyzed using a two-way, repeated measures ANOVA. There were no significant speed by footwear condition interactions. For impact peak, ankle stiffness and knee stiffness, there was no difference among the shod conditions but there were significant differences between the shod and barefoot conditions. Based on their strike index, participants in this study appeared to alter their footfall pattern from a rearfoot to a midfoot pattern when changing from running shod to barefoot. It may be concluded that the change in the impact characteristics is a result of changing footfall pattern rather than midsole thickness.
The three-dimensional motions of the pelvis and lumbar spine in walking were measured, in 20 normal adult males, using “Vicon” optoelectronic system, with reflective targets attached to lightweight rigs over the thoracolumbar junction and upper sacrum. Pelvic motion (using a room-based coordinate system) corresponded to published data. In the sagittal plane, the change in lumber lordosis across the gait cycle was consistent within subjects, but varied considerably between subjects. The phase relationships between pelvic tilt and lumbar lordosis also varied considerably between subjects. In the frontal plane, there was a much more consistent pattern of motion, spinal lateral bend generally following the pattern of pelvic obliquity, although there was some additional lateral bend, just prior to initial contact, superimposed on the generally linear relationship. The transverse plane showed similar waveforms between axial rotation of the pelvis and axial rotation of the lumbar spine, except that motion of the pelvis was of greater magnitude, and occurred later in the gait cycle than the motion of the lumbar spine. Since arm swing could be expected to increase axial rotation of the spine as a whole, this suggests that the thoracic spine undergoes greater motion than the lumbar spine, in this plane. Comparisons between the present study and two other published studies, using different methodology, showed only partial agreement.
Aim:
The purpose of this study was to determine the changes in running mechanics that occur when highly trained runners run barefoot and in a minimalist shoe, and specifically if running in a minimalist shoe replicates barefoot running.
Methods:
Ground reaction force data and kinematics were collected from 22 highly trained runners during overground running while barefoot and in three shod conditions (minimalist shoe, racing flat and the athlete's regular shoe). Three-dimensional net joint moments and subsequent net powers and work were computed using Newton-Euler inverse dynamics. Joint kinematic and kinetic variables were statistically compared between barefoot and shod conditions using a multivariate analysis of variance for repeated measures and standardised mean differences calculated.
Results:
There were significant differences between barefoot and shod conditions for kinematic and kinetic variables at the knee and ankle, with no differences between shod conditions. Barefoot running demonstrated less knee flexion during midstance, an 11% decrease in the peak internal knee extension and abduction moments and a 24% decrease in negative work done at the knee compared with shod conditions. The ankle demonstrated less dorsiflexion at initial contact, a 14% increase in peak power generation and a 19% increase in the positive work done during barefoot running compared with shod conditions.
Conclusions:
Barefoot running was different to all shod conditions. Barefoot running changes the amount of work done at the knee and ankle joints and this may have therapeutic and performance implications for runners.
This study aimed to determine the bra-breast forces generated in women with large breasts while these women wore different levels of breast support during both upright standing and treadmill running. The mean bilateral vertical component of the bra-breast force in standing was 11.7 ± 4.6 N, whereas during treadmill running the mean unilateral bra-breast force was 8.7 ± 6.4 N and 14.7 ± 10.3 N in the high and low support conditions, respectively. Furthermore, breast mass was significantly correlated with vertical breast displacement (R(2) = 0.62) in the high support condition. The wide range of breast masses of women with large breasts is an important consideration for designers of sports bras to ensure these bras can reduce force generation and breast discomfort by providing a high level of breast support while these women participate in physical activity.
A correctly fitting bra is essential for good health; this study investigates the use of professional bra fitting criteria to establish best-fit in an underwire bra commonly sold in the UK. A comparison was made between women's bra size as measured by the traditional bra fitting method with their recommended bra size based on professional bra fitting criteria. Forty-five female participants were recruited; their mode self-reported bra size was 34DD. Participants were measured in their own bra using the traditional bra-fitting method to establish their ‘traditional size’. A ‘best-fit’ bra size was recorded for participants based on professional bra fitting criteria. Significant differences were found between traditional and best-fit cup and band sizes (p < 0.001); the traditional method of bra fitting overestimated band size and underestimated cup size. As band size increased the traditional method also became more inaccurate (p < 0.001). It is recommended that women are educated in assessing their own bra fit using professional bra fitting criteria and less emphasis placed on determining absolute bra size.
Practitioner Summary: This is the first study to investigate using professional bra fitting criteria to establish best-fit in an underwired bra commonly sold in the UK. The traditional method of bra fitting was found to be inadequate, especially for larger-breasted women; the use of professional bra fitting criteria should be encouraged.
Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
Changes in ground reaction forces that result from different breast support conditions may have implications for sports performance and transmission of forces through the skeleton. The aim of this investigation was to compare kinetic variables and breast motion in a no-bra, everyday-bra and two sports-bra conditions. Following ethical approval, eight female participants with D-cup breasts had retro-reflective markers placed on the left and right nipples, anterior superior iliac spines and clavicles. Five calibrated ProReflex infra-red cameras (100 Hz; Qualisys) measured 3-D displacement of markers and synchronised kinetic data were collected using a force platform (500 Hz, Kistler 9281CA). A repeated measures one-way ANOVA revealed a significantly higher medial impact force in the no-bra condition (0.15 times body weight) compared with the compression sports-bra condition (0.12 times body weight) (F = 3.64 (3,21), p = 0.03). Findings suggest that inadequate breast support affects a female's running kinetics, which may have negative physiological consequences on sports performance.
In the present study, we examined the influence of shoe lacing on foot biomechanics in running. Twenty experienced rearfoot runners ran in six different lacing conditions across a force platform at a speed of 3.3 m . s(-1). Foot pronation during contact, tibial acceleration, and plantar pressure distribution of the right leg were recorded. The test conditions differed in the number of laced eyelets (1, 2, 3, 6 or 7) and in lacing tightness (weak, regular or strong). The results show reduced loading rates (P < 0.05) and pronation velocities (P < 0.01) in the tightest and highest lacing conditions. The lowest peak pressures under the heel and lateral midfoot (P < 0.01) were observed in the high (seven-eyelet) lacing pattern. Regular six-eyelet cross-lacing resulted in higher loading rates (P < 0.05) and higher peak heel pressures (P < 0.01) than seven-eyelet lacing, without any significant differences in perceived comfort. The low lace shoe conditions resulted in lower impacts (P < 0.01) and lower peak pressures under metatarsal heads III and V (P < 0.01), which is probably induced by the foot sliding within the shoe. A firm foot-to-shoe coupling with higher lacing leads to a more effective use of running shoe features and is likely to reduce the risk of lower limb injury.
The volume of the left and right breasts was measured daily in four nulliparous women during normal menstrual cycles and after the use of oral contraceptives. Breast volume increased significantly in the second half of both normal and contraceptive-controlled cycles. The mean total change in volume throughout the cycle was 100 ml under natural conditions and 66 ml on oral contraceptives.
Use of modified shoes and insole materials has been widely advocated to treat low back symptoms from running impacts, although considerable uncertainty remains regarding the effects of these devices on the rate of shock transmission to the spine. This study investigated the effects of shoes and insole materials on a) the rate of shock transmission to the spine, b) the temporal response of spinal musculature to impact loading, and c) the time interval between peak lumbar acceleration and peak lumbar muscle response. It was hypothesised that shoes and inserts a) decrease the rate of shock transmission, b) decrease the low back muscle response time, and c) shorten the time interval between peak lumbar acceleration and peak lumbar muscle response. Twelve healthy subjects were tested while jogging barefoot (unshod) or wearing identical athletic shoes (shod). Either no material, semi-rigid (34 Shore A), or soft (9.5 Shore A) insole material covered the force plate in the barefoot conditions and was placed as insole when running shod. Ground reaction forces, acceleration at the third lumbar level, and erector spinae myoelectric activity were recorded simultaneously. The rate of shock transmission to the spine was greater (p < 0.0003) unshod (acceleration rate: Means +/- SD 127.35 +/- 87.23 g/s) than shod (49.84 +/- 33.98 g/s). The temporal response of spinal musculature following heel strike was significantly shorter (p < 0.023) unshod (0.038 +/- 0.021 s) than shod (0.047 +/- 0.036 s). The latency between acceleration peak (maximal external force) and muscle response peak (maximal internal force) was significantly (p < 0.021) longer unshod (0.0137 +/- 0.022s) than shod (0.004 +/- 0.040 s). These results suggest that one of the benefits of running shoes and insoles is improved temporal synchronization between potentially destabilizing external forces and stabilizing internal forces around the lumbar spine.
To determine whether the current practice of prescribing distance running shoes featuring elevated cushioned heels and pronation control systems tailored to the individual's foot type is evidence-based.
MEDLINE (1950-May 2007), CINAHL (1982-May 2007), EMBASE (1980-May 2007), PsychInfo (1806-May 2007), Cochrane Database of Systematic Reviews (2(nd) Quarter 2007), Cochrane Central Register of Controlled trials (2(nd) Quarter 2007), SPORTSDiscus (1985-May 2007) and AMED (1985-May 2007). Review
English language articles were identified via keyword and medical subject headings (MeSH) searches of the above electronic databases. With these searches and the subsequent review process, controlled trials or systematic reviews were sought in which the study population included adult recreational or competitive distance runners, the exposure was distance running, the intervention evaluated was a running shoe with an elevated cushioned heel and pronation control systems individualised to the wearer's foot type, and the outcome measures included either running injury rates, distance running performance, osteoarthritis risk, physical activity levels, or overall health and wellbeing. The quality of these studies and their findings were then evaluated.
No original research that met the study criteria was identified either directly or via the findings of the six systematic reviews identified.
The prescription of this shoe type to distance runners is not evidence-based.
More systematic breast biomechanics research and better translation of the research outcomes are necessary to inform sports bra designs and develop effective evidence-based strategies to alleviate exercise-induced breast pain for women who want to participate in physical activity in comfort.
Although half the world's population will develop breasts, there is limited research documenting breast structure or motion. Understanding breast structure and motion, however, is imperative for numerous applications, such as breast reconstruction, breast modeling to better diagnose and treat breast pathologies, and designing effective sports bras. To be impactful, future breast biomechanics research needs to fill gaps in our knowledge, particularly related to breast composition and density, and to improve methods to accurately measure the complexities of three-dimensional breast motion. These methods should then be used to investigate breast biomechanics while individuals, who represent the full spectrum of women in the population, participate in a broad range of activities of daily living and recreation.
Este estudo e parte de um esforco internacional para validar um questionario internacional de atividade fisica (IPAQ) proposto pela Organizacao Mundial de Saude (1998), e que pretende servir como um instrumento mundial para determinar o nivel de atividade fisica em nivel populacional. O objetivo deste estudo foi determinar a validade do IPAQ em uma amostra de adultos brasileiros. A amostra foi constituida por257 homens e mulheres que responderam o IPAQ (versao da ultima semana, formas curta e longa) no inicio do estudo e apos 7 dias. Para validar o instrumento parte da amostra (n:.28) usou o sensor de movimento Computer Science & Aplications (CSA). A reprodutibilidade do questionario foi determinada depois de 7 dias e a correlacao de Spearman foi significante e alta (rho=0,69 - 0,71:p 7 ultimos dias apresentam resultados similares. Concluimos que as formas de IPAQ foram aceitaveis e apresentaram resultados similares a outros instrumentos para medir nivel de atividade fisica, no entanto pela primeira vez o estudo de validacao diversos paises e culturas foram envolvidos na validacao do instrumento.
To assess the effectiveness of breast support previous studies monitored breast kinematics and kinetics, subjective feedback, muscle activity (EMG), ground reaction forces (GRFs) and physiological measures in isolation. Comparing these variables within one study will establish the key performance variables that distinguish between breast supports during activities such as running. This study investigates the effects of changes in breast support on biomechanical, physiological and subjective measures during running. Ten females (34D) ran for 10 min in high and low breast supports, and for 2 min bare breasted (2.8 m·s(-1)). Breast and body kinematics, EMG, expired air and heart rate were recorded. GRFs were recorded during 10 m overground runs (2.8 m·s(-1)) and subjective feedback obtained after each condition. Of the 62 variables measured, 22 kinematic and subjective variables were influenced by changes in breast support. Willingness to exercise, time lag and superio-inferior breast velocity were most affected. GRFs, EMG and physiological variables were unaffected by breast support changes during running. Breast displacement reduction, although previously advocated, was not the most sensitive variable to breast support changes during running. Instead breast support products should be assessed using a battery of performance indicators, including the key kinematic and subjective variables identified here.
Background:
While it is generally accepted that large breast sizes in females contribute to back pain and poor posture, the effects of breast size on spinal motion and muscle activation characteristics are poorly understood.
Objective:
This study examined the relationship between breast size, spine motion, and trunk muscle activation.
Methods:
Fifteen university-aged females, free of back pain symptoms, were tested. Breast sizes were calculated, and three-dimensional spine motion and activation from five trunk muscles bilaterally were measured during standing and trunk flexion movements. Correlations between breast size and motion and muscle activation measures were assessed.
Results:
Head and trunk angles were strongly, negatively correlated to breast size during upright standing; thoracic angles were moderately, positively correlated to breast size during thoracic flexion movements. Trunk muscles showed positive, moderate-strength relationships with breast size during upright standing and some trunk movements.
Conclusions:
These findings provide a preliminary indication that increasing breast sizes contribute to altered postures and increased muscle activation in a non-clinical population, and constitute a baseline for the study of females with a full range of breast sizes. Further research is required to confirm the generalizability of these findings to other sizes, in order to inform strategies for the prevention or reduction of back pain, as well as diagnosis, treatment, and rehabilitation techniques associated with breast size and back pain.
During the ground contact phase of running, the body's mass is rapidly decelerated resulting in forces that propagate through the musculoskeletal system. The repetitive attenuation of these impact forces is thought to contribute to overuse injuries. Modern running shoes are designed to reduce impact forces, with the goal to minimize running related overuse injuries. Additionally, the fore/mid foot strike pattern that is adopted by most individuals when running barefoot may reduce impact force transmission. The aim of the present study was to compare the effects of the barefoot running form (fore/mid foot strike & decreased stride length) and running shoes on running kinetics and impact accelerations. 10 healthy, physically active, heel strike runners ran in 3 conditions: shod, barefoot and barefoot while heel striking, during which 3-dimensional motion analysis, ground reaction force and accelerometer data were collected. Shod running was associated with increased ground reaction force and impact peak magnitudes, but decreased impact accelerations, suggesting that the midsole of running shoes helps to attenuate impact forces. Barefoot running exhibited a similar decrease in impact accelerations, as well as decreased impact peak magnitude, which appears to be due to a decrease in stride length and/or a more plantarflexed position at ground contact.
© Georg Thieme Verlag KG Stuttgart · New York.
Because bra design may influence the breast discomfort experienced by female athletes, we studied whether there is a difference in support provided by selected bras, the normal acceptable range of breast movement for comfort, and the effects of binding the breasts over a bra in jogging. There was a significant difference in the linear displacement of the eight sports bras, but not between the size groups. The mass of the breast in conjunction with the velocity of movement may be related to discomfort while jogging, and binding over a bra prevents from 44% to 45% of the movement.
Running is one of the most popular leisure sports activities. Next to its beneficial health effects, negative side effects in terms of sports injuries should also be recognised. Given the limitations of the studies it appears that for the average recreational runner, who is steadily training and who participates in a long distance run every now and then, the overall yearly incidence rate for running injuries varies between 37 and 56%. Depending on the specificity of the group of runners concerned (competitive athletes; average recreational joggers; boys and girls) and on different circumstances these rates vary. If incidence is calculated according to exposure of running time the incidence reported in the literature varies from 2.5 to 12.1 injuries per 1000 hours of running. Most running injuries are lower extremity injuries, with a predominance for the knee. About 50 to 75% of all running injuries appear to be overuse injuries due to the constant repetition of the same movement. Recurrence of running injuries is reported in 20 to 70% of the cases. From the epidemiological studies it can be concluded that running injuries lead to a reduction of training or training cessation in about 30 to 90% of all injuries, about 20 to 70% of all injuries lead to medical consultation or medical treatment and 0 to 5% result in absence from work. Aetiological factors associated with running injuries include previous injury, lack of running experience, running to compete and excessive weekly running distance. The association between running injuries and factors such as warm-up and stretching exercises, body height, malalignment, muscular imbalance, restricted range of motion, running frequency, level of performance, stability of running pattern, shoes and inshoe orthoses and running on 1 side of the road remains unclear or is backed by contradicting or scarce research findings. Significantly not associated with running injuries seem age, gender, body mass index, running hills, running on hard surfaces, participation in other sports, time of the year and time of the day. The prevention of sports injuries should focus on changes of behaviour by health education. Health education on running injuries should primarily focus on the importance of complete rehabilitation and the early recognition of symptoms of overuse, and on the provision of training guidelines.
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.
This study sought to analyse the behaviour of the average spinal posture using a novel investigative procedure in a maximal incremental effort test performed on a treadmill. Spine motion was collected via stereo-photogrammetric analysis in thirteen amateur athletes. At each time percentage of the gait cycle, the reconstructed spine points were projected onto the sagittal and frontal planes of the trunk. On each plane, a polynomial was fitted to the data, and the two-dimensional geometric curvature along the longitudinal axis of the trunk was calculated to quantify the geometric shape of the spine. The average posture presented at the gait cycle defined the spine Neutral Curve. This method enabled the lateral deviations, lordosis, and kyphosis of the spine to be quantified noninvasively and in detail. The similarity between each two volunteers was a maximum of 19% on the sagittal plane and 13% on the frontal (p<0.01). The data collected in this study can be considered preliminary evidence that there are subject-specific characteristics in spinal curvatures during running. Changes induced by increases in speed were not sufficient for the Neutral Curve to lose its individual characteristics, instead behaving like a postural signature. The data showed the descriptive capability of a new method to analyse spinal postures during locomotion; however, additional studies, and with larger sample sizes, are necessary for extracting more general information from this novel methodology.
Copyright © 2015 Elsevier Ltd. All rights reserved.
A method for photogrammetric data reduction without the necessity for neither fiducial marks nor initial approximations for inner and outer orientation parameters of the camera has been developed. This approach is particularly suitable for reduction of data from non-metric photography,
but has also distinct advantages in its application to metric photography. Preliminary fictitious data tests indicate that the approach is promising. Experiments with real data are underway.
The purpose of this study was to determine the correlation between the back shape of the lumbar region and the spinal loads during activities performed in the sagittal plane. Measurements were performed in four subjects who had suffered from a compression fracture of a lumbar vertebral body which was treated with a telemeterized vertebral body replacement that is able to measure six load components in vivo. An Epionics SPINE measurement system was used to determine the lumbar lordosis angle. The relationship between the lordosis angle and the corresponding loads was quantified with the Spearman's rank correlation coefficient method. Measurements were performed during thirteen exercises in lying, standing or sitting. During upper body flexion, the force increased on average by approximately 285N and the lordosis angle decreased by 15°. The change of the force for elevating 30N in one hand was on average approximately 190N and for the lordosis angle 2°. Correlation coefficients greater than 0.6 were found for exercises that involved both large back shape and load changes, such as upper body flexion. A strong increase in spinal load can be associated with an increase or a decrease of the lordosis angle. Only for considerable changes of the lordosis angle in an upright body position was a strong correlation between lordosis angle and implant force found.
Background For female marathon runners, breast pain (mastalgia) may be an important issue which has yet to be considered. This study aimed to determine the prevalence and severity of mastalgia in female marathon runners, identify factors that increase mastalgia and methods used to overcome mastalgia, and explore the impact that mastalgia may have on marathon training.
Methods 1397 female marathon runners were surveyed at the 2012 London Marathon Registration. All participants who completed the four-part, 30-question survey in its entirety have been included in the analysis (n=1285).
Results 32% of participants experienced mastalgia. This was significantly related to cup size and was greater during vigorous compared with moderate physical activity. Exercise-related factors were the primary factors reported to increase mastalgia participation. Seventeen per cent of symptomatic participants reported that mastalgia affected their exercise behaviour. Methods reportedly used to overcome mastalgia included pain medication and firm breast support; however, 44% of participants took no measures to relieve symptoms despite over half describing their mastalgia as discomforting.
Conclusions Mastalgia was experienced by a third of marathon runners and was found to be related to breast size which has previously been unreported. The link between exercise and mastalgia has yet to be established; however, this study identified that exercise was the most prevalent factor in mastalgia occurrence which may have implications for its management. The number of participants who took no measures to relieve their mastalgia, or resorted to pain medication, highlights the importance and significance of research into exercise-related mastalgia.
Eight sports bras were compared and evaluated to determine the amount of biomechanical support they provide for small-, medium-, and large-breasted women (N=59) while jogging. Findings showed that the Exercise Sports Top and the Lady Duke bras allowed the least amount of breast movement. (Author/CB)
Tibial rotation during foot pronation has been proposed as a key factor in running related injuries. Precise analysis of knee motion during running, including the analysis of motion in the coronal plane, is difficult, and the effect of the wearing shoes on tibial rotation during running is unknown. Therefore, we aimed to determine the effect of wearing shoes in reducing tibial rotation during running. Fifteen healthy subjects (nine males, six females) participated in this study; 25 markers were secured on the left lower extremity of each subject. Three-dimensional kinematic data were collected using the MAC3D System (Motion Analysis Co.). The data were processed using the point cluster technique (Andriacchi et al. 1998, J Biomech Eng 120, 743). The subjects were required to run (a) barefoot and (b) while wearing athletic running shoes (Adidas Response Cushion). Tibial motion with respect to the femur was assessed in the stance phase. The internal/external rotation, adduction/abduction and flexion of knee joint were analyzed for a period of 100 ms after foot strike. In both the conditions, all subjects experienced internal tibial rotation after foot strike. During the 100-ms period after foot strike, the shoes reduced the amount of tibial rotation during running (barefoot 16.0 ± 4.1°, shod 13.7 ± 5.3°). The angular change of the knee flexion was increased with running shoe (barefoot 20.8 ± 4.9°, shod 26.5 ± 4.2°). These findings suggest that tibial rotation can be reduced by wearing athletic running shoes.
Despite the technological developments in modern running footwear, up to 79% of runners today get injured in a given year. As we evolved barefoot, examining this mode of running is insightful. Barefoot running encourages a forefoot strike pattern that is associated with a reduction in impact loading and stride length. Studies have shown a reduction in injuries to shod forefoot strikers as compared with rearfoot strikers. In addition to a forefoot strike pattern, barefoot running also affords the runner increased sensory feedback from the foot-ground contact, as well as increased energy storage in the arch. Minimal footwear is being used to mimic barefoot running, but it is not clear whether it truly does. The purpose of this article is to review current and past research on shod and barefoot/minimal footwear running and their implications for running injuries. Clearly more research is needed, and areas for future study are suggested.
Barefoot running, which was how people ran for millions of years, provides an opportunity to study how natural selection adapted the human body to run. Because humans evolved to run barefoot, a barefoot running style that minimizes impact peaks and provides increased proprioception and foot strength, is hypothesized to help avoid injury, regardless of whether one is wearing shoes.
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.
Although breast pain has been related to vertical breast displacement and velocity, the influence of breast support on multi-planar breast kinematics and breast comfort has yet to be ascertained. The aims of this study were to investigate multi-planar breast displacement, velocity, and acceleration with and without breast support during running and to establish the correlation with breast comfort. Fifteen females ran at 2.8 m x s(-1) in no bra, an everyday bra, and a sports bra. Three-dimensional coordinates of breast and body markers were tracked during ten gait cycles and following each trial the participants rated their breast comfort. Relative breast displacement was calculated and derived for velocity and acceleration. Vertical breast displacement, velocity, and acceleration peaked at, before, and after mid-stance, respectively. The patterns of displacement and velocity trajectories were unaffected by increasing breast support, though the magnitudes were significantly reduced. The magnitude and trajectory of breast acceleration was unaffected by increasing breast support and showed no correlation with comfort. Breast velocity displayed the strongest relationship to comfort (r = 0.61). Considerable mediolateral and anteroposterior breast kinematics were identified, suggesting that future studies and bra design may benefit from three-dimensional analysis. In conclusion, improvements in breast support may be defined by reductions in breast velocity and displacement.
This study aimed to assess the trajectory of breast displacement in 3 dimensions during walking and running gait, as this may improve bra design and has yet to be reported. Fifteen D-cup participants had reflective markers attached to their nipples and trunk to monitor absolute and relative breast displacement during treadmill walking (5 kph) and running (10 kph). During the gait cycle, the breast followed a figure-of-eight pattern with four movement phases. Despite a time lag in resultant breast displacement compared with the trunk, similar values of breast displacement were identified across each of the four phases. Fifty-six percent of overall breast movement was vertical, suggesting that 3-D assessment and the elimination of trunk movement in 6 degrees of freedom are essential to accurately report breast displacement during the gait cycle.
Running is one of the most popular leisure sports activities. Next to its beneficial health effects, negative side effects in terms of sports injuries should also be recognised. Given the limitations of the studies it appears that for the average recreational runner, who is steadily training and who participates in a long distance run every now and then, the overall yearly incidence rate for running injuries varies between 37 and 56%. Depending on the specificity of the group of runners concerned (competitive athletes; average recreational joggers; boys and girls) and on different circumstances these rates vary. If incidence is calculated according to exposure of running time the incidence reported in the literature varies from 2.5 to 12.1 injuries per 1000 hours of running. Most running injuries are lower extremity injuries, with a predominance for the knee. About 50 to 75% of all running injuries appear to be overuse injuries due to the constant repetition of the same movement. Recurrence of running injuries is reported in 20 to 70% of the cases. From the epidemiological studies it can be concluded that running injuries lead to a reduction of training or training cessation in about 30 to 90% of all injuries, about 20 to 70% of all injuries lead to medical consultation or medical treatment and 0 to 5% result in absence from work. Aetiological factors associated with running injuries include previous injury, lack of running experience, running to compete and excessive weekly running distance. The association between running injuries and factors such as warm-up and stretching exercises, body height, malalignment, muscular imbalance, restricted range of motion, running frequency, level of performance, stability of running pattern, shoes and inshoe orthoses and running on 1 side of the road remains unclear or is backed by contradicting or scarce research findings. Significantly not associated with running injuries seem age, gender, body mass index, running hills, running on hard surfaces, participation in other sports, time of the year and time of the day. The prevention of sports injuries should focus on changes of behaviour by health education. Health education on running injuries should primarily focus on the importance of complete rehabilitation and the early recognition of symptoms of overuse, and on the provision of training guidelines.
The shocks imparted to the foot during locomotion may lead to joint-degenerative diseases and jeopardize the visual-vestibular functions. The body relies upon several mechanisms and structures that have unique viscoelastic properties for shock attenuation. The purpose of the present study was to determine whether impact severity and initial knee angle (IKA) could alter the shock transmission characteristics of the body. Impacts were administered to the right foot of 38 subjects with a human pendulum device. Combinations of velocities (0.9, 1.05 and 1.2 m s-1) and surfaces (soft and hard foams) served to manipulate impact severity in the first experiment. Three IKA (0, 20 and 40 degrees) were examined in the second experiment. Transmission between shank and head was characterized by measuring the shock at these sites with miniature accelerometers. Velocity and surface had no effect on the frequency profile of shock transmission suggesting a consistent response of the body to impact severity. Shank shock power spectrum features accounted for the lower shock ratio (head/shank) measured under the hard surface condition. IKA flexion caused considerable reduction in effective axial stiffness of the body (EASB), 28.7-7.9 kNm-1, which improved shock attenuation. The high correlation (r = 0.97) between EASB and shock ratio underscored the importance of EASB to shock attenuation. The present findings provide valuable information for the development of strategies aimed at protecting the joints, articular cartilage, spine and head against locomotor shock.
Breast pain is common during exercise, occurring in up to 56% of subjects in some surveys. This pain is mainly associated with the movement of breast tissue. In an attempt to analyse this movement and the resulting pain, the movement of the female breast tissue was quantified in four conditions of breast support ("sports bra", "fashion bra", "crop top" and bare breasted) during four different activities (running, jogging, aerobics march and walking). These activities represented general patterns of exercise for adult females in Australian society. All three subjects were healthy, active, young women of varying breast size (12B, 14B & 14C) that were typical of young women. Two of the subjects had noted breast pain whilst exercising. The results showed that wearing external support for the breast tissue reduced absolute vertical movement and maximum downward deceleration force on the breast. Support also reduced perceived pain. When compared to other forms of breast support a "sports bra" (brassiere designed for breast support whilst exercising) provided superior support for the breast in relation to the amplitude of movement, deceleration forces on the breast, and perceived pain. The data indicates that adult females should wear appropriate breast support to reduce perceived breast discomfort or pain. Of the three garments examined in this study, the fitted sports bra provided superior support and pain reduction.
To describe the baseline characteristics of participants starting a 25-week marathon training program, and their relationship to injury risk factors.
Prospective survey.
Community-based marathon training program.
1,548 of 2,314 registrants for the Houston Fit Marathon Training Program (mean age 35.8 +/- 9.3 years, mean body mass index 24.3 +/- 3.9, 63% female).
4-page survey administered at registration.
Running experience, training practices, demographics, chronic medical problems and previous injuries.
Females were more likely to be classified as underweight and males as overweight or obese (p < 0.0001). The mean number of years of running experience was 6.2 +/- 6.2. Most (87.5%) planned to train at a 9-minute mile or slower pace. 52.3% of the participants had not previously trained for a marathon. In the 3 months prior to starting the program 16.1% had been sedentary. Those runners who had not previously completed a marathon and not previously trained with Houston Fit had a higher prevalence of baseline training techniques that could be risk factors for injury. During the previous 3 years, 38.1% reported having an injury, and 35% of all injuries were still symptomatic at the start of the program.
Training programs for the marathon attract more female athletes and those with less running and marathon experience. The prevalence of being overweight or obese is 35.6%. 16.1% are sedentary during the 3 months before starting this program. Training programs must take measures to establish baseline fitness, to educate on injury prevention training techniques, and to set appropriate fitness goals.
The research study shows that many patients wanting to start a marathon training program are relatively untrained and inexperienced with reference to endurance running. These patients will need special care and education so as to minimize injury and maximize the effect on their physical activity habits.
Macromastia usually is associated with the physical and psychological symptoms reported comprehensively by many studies. Reduction mammoplasty seems to be the most reasonable solution for these symptoms, and many articles have reported improvement of these complaints after surgery. Some authors have postulated that the anatomic mechanisms of postural aberrations are heavy breasts and related pain symptoms. However, limited numbers of studies have tried to explain the effect of the heavy breasts on the vertebral column.
This study enrolled 100 females in four groups according to their breast cup sizes (groups A, B, C, D). All four groups were compared with each other statistically using one-way analysis of variance (ANOVA) followed by a post hoc test according to the body mass index (BMI) as well as the thoracic kyphosis, lumbar lordosis, and sacral inclination angles.
The BMI was significantly higher in the D cup-sized breast group. There was a statistically significant difference between groups A and D in terms of the thoracic kyphosis and the lumbar lordosis angles, and between groups B and D in terms of the lumbar lordosis angle. No statistically significant difference was detected between the groups in terms of the sacral inclination angle.
Breast size seems to be an important factor that affects posture, especially the thoracic kyphosis and lumbar lordosis angles.
How do respiratory state and measurement method affect bra size calculations?
- McGhee
McGhee, D.E., Steele, J.R., 2006. How do respiratory state and measurement method
affect bra size calculations?. Br. J. Sports Med. 40, 970-974. https://doi.org/
10.1136/bjsm.2005.025171.
Comparison between of estimators Robust and Classical in repeated measurement experiments analysis
- Jeleel