Joanna Scurr

The effect of breast support on the kinematics of the breast during the running gait cycle

Abstract 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 · 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.

The effect of breast support on kinetics during overground running performance

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 females running kinetics, which may have negative physiological consequences on sports performance.

Evaluation of professional bra fitting criteria for bra selection and fitting in the UK

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 womens 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.

Supported and unsupported breast displacement in three dimensions across treadmill activity levels.

Abstract 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.

An assessment of the reliability and standardisation of tests used to elicit reference muscular actions for electromyographical normalisation.

Prior to implementing a normalisation method, the standardisation and reliability of the method needs to be examined. This investigation aimed to assess the reliability of EMG amplitudes and test outputs from proposed normalisation methods for the triceps surae. Sixteen participants completed isometric (maximum and sub-maximum); isokinetic (1.05rad/s, 1.31rad/s and 1.83rad/s) squat jump and 20m sprint conditions, on 3 separate occasions over 1week. The EMG data was collected from the medial and lateral gastrocnemius (MG and LG) and soleus (SOL). Log transformed typical error measurements (TEM(CV%)) assessed EMG signal and test output reliability across the three sessions. Only the squat jump provided acceptable EMG reliability for all muscles both between days (SOL: 13%; MG: 14.5%; LG: 11.8%) and between weeks (SOL: 14.5%; MG: 12.9%; LG: 8.9%), with the sprint only showing poor reliability in the LG between days (16.3%). Acceptable reliability for the isometric and isokinetic conditions were muscle and re-test period dependant. Reliable output was found for the squat jump (4.1% and 3.6%), sprint (0.8% and 0.6%) and 1RM plantar flexion test (2.8% and 3.5%) between days and weeks, respectively. Isokinetic plantar flexion displayed poor reliability at all velocities between days and weeks. It was concluded that the squat jump provides a standardised and reproducible reference EMG value for the triceps surae for use as a normalisation method.

Perceived Exertion is Related to Muscle Activity During Leg Extension Exercise

This study examined the relationship between ratings of perceived exertion and muscle activity during dynamic leg extension exercise using a resistance exercise specific OMNI-RPE scale. Twenty volunteers (10 males, 10 females, age 22.2 ± 3.1 yr) performed one set of leg extension exercise at 30%, 60%, and 90% of their one-repetition maximum (1-RM). OMNI-RPE responses were assessed for both the active muscle (OMNI-AM) and the overall body (OMNI-O) following each intensity. Electromyography (EMG) data were collected from the rectus femoris, vastus lateralis, and vastus medialis muscles. A two-factor repeated measures ANOVA showed a significant OMNI-RPE (region) X intensity interaction (p < 0.01). Both OMNI-AM and OMNI-O increased with exercise intensity, and RPE-AM was higher than RPE-O at all intensities. EMG activity increased with exercise intensity in all muscle groups (all p < 0.01). Muscle activity was significantly and positively related to OMNI-RPE in both the active muscle and overall body (all p < 0.01). The OMNI-Res RPE scale may be a promising technique for regulating resistance training intensity.

The experience of breast pain (mastalgia) in female runners of the 2012 London Marathon and its effect on exercise behaviour

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.

The relationship between breast size and anthropometric characteristics

Current clinical selection criteria for mammaplasty use weight‐related parameters, and weight loss is recommended as a nonsurgical intervention to reduce breast size. However, research has not firmly established if breast size is related to body size and composition. This study aims to investigate anthropometric characteristics in smaller and larger breasted women and identify predictors of breast mass.

Bilateral contact ground reaction forces and contact times during plyometric drop jumping

Ball, NB, Stock, CG, and Scurr, JC. Bilateral contact ground reaction forces and contact times during plyometric drop jumping. J Strength Cond Res 24(10): 2762-2769, 2010-Drop jumping (DJ) is used in training programs aimed to improve lower extremity explosive power. When performing double-leg drop jumps, it is important to provide an equal stimulus to both legs to ensure balanced development of the lower legs. The aim of this study was to bilaterally analyze the ground reactions forces and temporal components of drop jumping from 3 heights. Ten recreationally active male subjects completed 3 bounce-drop jumps from 3 starting heights (0.2, 0.4, and 0.6 m). Two linked force platforms were used to record left- and right-leg peak vertical force, time to peak force, average force, ground contact time, impulse and time differential. Between-height and between-leg comparisons for each variable were made using a multivariate analysis of variance with post hoc Wilcoxon tests (p < 0.05). Results indicated that force and time variables increased as drop jump height increased (p < 0.0001). Post hoc analyses showed that at 0.2- and 0.4-m bilateral differences were present in the time to peak force, average force, and impulse. No bilateral differences for any variables were shown at 0.6-m starting height. The contact time for all jumps was <0.26 seconds. At 0.2 m, only 63% of the subjects had a starting time differential of <0.01 seconds, rising to 96.3% at 0.6 m. The results indicated that 0.6 m is the suggested drop jump height to ensure that no bilateral differences in vertical forces and temporal components occur; however, shorter contact times were found at the lower heights.

Influential factors of bra purchasing in older women

Purpose – In addition to the psychological differentiation of older women, ageing has numerous effects on the breast, influencing the volume, density and constitution of the tissue. It is currently unknown how these changes may affect bra requirements and bra consumer behaviour. The purpose of this paper is to explore factors of importance in bras in a cohort of women aged 45 to 65 years, whilst considering purchasing behaviour, brand loyalties and self‐image.Design/methodology/approach – Following a grounded theoretical perspective, this study was exploratory in nature, including a mixture of five semi‐structured interviews and two focus groups with women, aged 45 to 65 years, to discuss bra habits, considerations, and influential factors of purchasing. Data were content analysed with additional frequency analysis.Findings – The paper provides five key dimensions within which older women focus their attentions when purchasing bras. These are aesthetics, comfort, practicalities of bra purchase, breast sup...