Do the feet of male and female netball players differ in shape? Implications for shoe design.

A large proportion of netball players suffer foot-related problems and pain and are dissatisfied with current netball-specific footwear. To improve the fit and functionality of netball-specific shoes, we must understand the shape of these players' feet and determine whether any sex differences exist. Five hundred and two representative-level netball players (n = 251 male; n = 251 female) had their feet three-dimensionally scanned. We then used a validated MATLAB code to automatically extract 10 measurements to characterise each participant's foot shape. Differences between men and women for the absolute values and those normalised to foot length and stature were identified using independent samples t-tests with a Bonferroni adjusted alpha level. The size and shape of male netball players' feet differed significantly from their female counterparts. Males had significantly larger absolute and normalised foot measurements than females, notably at the ball of the foot, heel and instep (p < 0.001). Netball shoe manufacturers should develop unique lasts for each sex and foot size and should offer a more extensive range of shoe lengths and widths to netball players. Such considerations will help optimise shoe fit and comfort and, in turn, reduce foot-related problems and pain associated with ill-fitting footwear.

Numerical model of pressure generated by elastic compression garments on a compressible human limb analogue.

OBJECTIVE: This study aimed to formulate a numerical approach (finite element modelling (FEM)) to calculate pressure values generated by compression garments on a compressible limb analogue, and to validate the numerical approach using experimental measurements. Existing models were also compared. METHOD: Experimentally measured pressure values and deformation caused by compression bands on a compressible human limb analogue were compared with values predicted using the Young-Laplace equation, a previously formulated analytical model and the FEM. RESULTS: The FEM provided greater accuracy in predicting the pressure generated by compression bands compared to existing models. The FEM also predicted deformation of the limb analogue with good agreement relative to experimental values. CONCLUSION: It was concluded that modelling the non-uniform manner in which the way a limb analogue is compressed should be incorporated into future modelling of the pressures generated by compression garments on a compressible limb analogue. DECLARATION OF INTEREST: The authors have no conflicts of interest to declare.

Do foot type classifications differ between male and female netball players? A cluster analysis.

We must better understand the foot type classifications of netball players to develop sex and size-specific shoe lasts. Five hundred and two representative-level netball players (n = 251 male; n = 251 female) had their feet three-dimensionally scanned. A validated MATLAB code was used to extract six different foot measurements from these scans automatically. We then used a two-step cluster analysis and chi-squared tests to classify foot types and determine the effect of sex on each cluster, respectively. Five foot types were identified (Extra long-and-wide, Long-and-wide, Flat, Tapered and Short-and-narrow), with sex significantly affecting foot type classification. The feet of players wearing smaller shoe sizes were often Short-and-narrow and Tapered, whereas the feet of players wearing larger sizes tended to be more Extra long-and-wide and Long-and-wide. These results highlight that netball players have a wide variety of foot types; manufacturers should use these data to develop future grading systems to improve the fit and functionality of netball-specific footwear.

This study aimed to investigate the foot types of netball players. The results demonstrated that five main foot types should be used to inform future shoe last designs and size grading systems. These findings have implications for improving the fit and functionality of netball shoes, particularly for men.

How much error is associated with calculating breast volume from three-dimensional breast scans obtained when women are standing? Implications for bra design and bra fit.

BACKGROUND: A lying prone position is recommended when scanning women's breasts to ensure the entire breast can be visualised. However, several large databases contain three-dimensional scans of women's breasts and torsos that were obtained while the women were standing. This study aimed to establish the error associated with calculating breast volume from three-dimensional breast scans taken when women were standing relative to lying prone. METHODS: Breast volume was derived for 378 women with Small, Medium, Large and Hypertrophic breast sizes from scans taken while the women were standing and then lying prone. RESULTS: The magnitude of error associated with breast volume derived from scans obtained while women stood compared to lying prone, ranged from ∼8-22% and increased with increasing breast size. CONCLUSION: Errors associated with breast volume data derived from breast scans collected while women stand must be accounted for, particularly for women with Medium, Large and Hypertrophic breast sizes. Practitioner summary: This original research provides evidence for bra designers and manufacturers on the degree of error associated when using breast scans obtained while women were standing, such as those scans readily available in large scanning databases. These errors increase with increasing breast size and must be accounted for when sizing and designing bra cups.

Effect of work boot shaft stiffness and sole flexibility on boot clearance and shank muscle activity when walking on simulated coal mining surfaces: implications for reducing trip risk.

Mining work boot shaft stiffness and sole flexibility variations are likely to affect how a miner moves their foot to clear the ground thus influencing their risk of tripping. Despite the potential negative consequences associated with tripping, limited research has investigated how these boot design features might contribute to a miner's trip risk. Therefore, this study aimed to investigate the effects of systematic variations to boot shaft stiffness and sole flexibility on lower limb alignment and shank muscle activity at toe off and boot clearance during initial swing when 20 males walked across two simulated coal mining surfaces. Although knee and hip alignment remained constant, changes to boot shaft stiffness and sole flexibility significantly interacted to influence the shank muscle activity and ankle alignment displayed at toe off. To reduce the risk of tripping, underground coal miners should avoid a boot with a stiff shaft, regardless of the sole flexibility.

Underground coal miners experience a high incidence of work-related lower limb injuries, with tripping a main cause. This study systematically investigated two boot design features that are likely to influence a miner's risk of tripping. To reduce trip risk, coal miners should avoid a boot with a stiff shaft.

Breast Biomechanics: What Do We Really Know?

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.

Physical side-effects following breast reconstructive surgery impact physical activity and function.

PURPOSE: To investigate the incidence and severity of physical side-effects experienced by women following breast reconstructive surgery and the effect of these side-effects on physical activity and function. METHODS: Two hundred and thirty-one Australian women (55 years SD 6.5) who had previously had breast reconstruction surgery retrospectively self-reported the incidence and severity of eight physical side-effects and the perceived effect of these side effects on six physical functions, at three time points after their surgery. The frequency of the combined incidence/severity scores and their impact at the three time points were tabulated and compared using Chi-squared tests. A general linear regression was used to identify characteristics associated with moderate-very high (≥ 5/10) combined incidence/severity scores. RESULTS: At 6 months following surgery, approximately 50% of respondents reported moderate to very high incidence/severity scores for physical side-effects across multiple body regions, which were perceived to limit their physical function and activity levels. The highest incidence/severity scores were associated with the following: (i) pre-existing physical problems before surgery, (ii) post-operative complications (seroma, infection, necrosis), and (iii) autologous rather than implant-based reconstructions. CONCLUSION: A large percentage of women reported moderate to severe physical side-effects across multiple body regions following breast reconstructive surgery. These side-effects were perceived to negatively impact both physical function and activity. Early intervention, education and treatment are recommended to alleviate these issues and minimise their negative impact.

Can Physical Characteristics and Sports Bra Use Predict Exercise-Induced Breast Pain in Elite Female Athletes?

OBJECTIVE: To evaluate whether a simple 4-factor model using self-reported data could be used to predict exercise-induced breast pain in elite female athletes. DESIGN: Survey study. SETTING: Online or hard-copy surveys completed at sporting competitions and training facilities around Australia. PARTICIPANTS: Four hundred ninety female athletes competing nationally or internationally across 49 sports. INDEPENDENT VARIABLES: A binomial logistic regression analysis was used to evaluate the strength of a predictive model that included 2 continuous independent variables (age and body mass index) and 2 binary independent variables (breast size and sports bra use). Odds ratios were also calculated to determine the likelihood of an athlete reporting exercise-induced breast pain in association with each of the 4 variables. MAIN OUTCOME MEASURES: Exercise-induced breast pain was the binary dependent variable. RESULTS: The model incorporating athlete age, breast size, body mass index, and sports bra use was found to be statistically significant, but weak, in its ability to predict exercise-induced breast pain in elite female athletes (correctly identified 66% of athletes). For every 1-year increase in age, a significant 2.6% increase in the likelihood of experiencing exercise-induced breast pain was observed. Athletes with medium-to-hypertrophic sized breasts were 5.5 times more likely to experience exercise-induced breast pain than athletes with small breasts. CONCLUSIONS: Although the current model was not sensitive enough for use by clinicians and coaches, age and breast size were both identified as critical variables in the prediction of exercise-induced breast pain. Future research is encouraged to investigate whether incorporating additional variables such body fat percentage, bra fit, and other relevant factors can add strength to the model.

Rate of loading, but not lower limb kinematics or muscle activity, is moderated by limb and aerial variation when surfers land aerials.

We aimed to determine whether there were any differences in how surfers used their lead and trail limbs when landing two variations of a simulated aerial manoeuvre, and whether technique affected the forces generated at landing. Fifteen competitive surfers (age 20.3 ± 5.6 years, height 178.2 ± 9.16 cm, mass 71.0 ± 10.5 kg) performed a Frontside Air (FA) and Frontside Air Reverse (FAR), while we collected the impact forces, ankle and knee muscle activity, and kinematic data. A principal component analysis (PCA) was used to reduce 41 dependent variables into 10 components. A two-way MANOVA revealed that although there were no limb x aerial variation interactions, surfers generated significantly higher relative loading rates at landing for the trail limb compared to the lead limb (+28.8 BW/s; F(1,303) = 20.660, p < 0.0001, η2 = 0.064). This was likely due to the surfers "slapping" the trail limb down when landing, rather than controlling placement of the limb. Similarly, higher relative loading rates were generated when landing the FA compared to the FAR (+23.6 BW/s; F(1,303) = 31.655, p < 0.0001, η2 = 0.095), due to less time over which the forces could be dissipated. No relationships between aerial variation or limb were found for any of the kinematic or muscle activity data. Practitioners should consider the higher relative loading rates generated by a surfer's trail limb and when surfers perform a FA when designing dry-land training to improve the aerial performance of surfing athletes.

Can we predict the landing performance of simulated aerials in surfing?

This study explored which technical and physical attributes could predict superior and/or safe landing performance when surfers performed variations of a simulated aerial task. Fourteen surfers (age 20.6 ± 5.7 years, height 178.1 ± 9.50 cm, mass 70.6 ± 10.8 kg) had their lower limb mobility, squat jump, countermovement jump, and drop-and-stick landing performance assessed. Performance of two aerial variations (Frontside Air (FA) and Frontside Air Reverse (FAR)) was also measured, with variables relating to technical performance (critical feature and subjective ratings) and potential injury risk (relative total peak landing force and loading rates) collected. Multiple linear regressions were used to predict performance of both aerial variations based on a subset of independent variables. Four models could predict performance. Predicted technical capability in the FAR was mostly influenced by lead limb hip extension and lead limb knee flexion range of motion. Potential injury risk when surfers perform an FA and FAR was predicted to be mitigated by increasing lead ankle dorsiflexion range of motion, as well as trail hip extensor mobility to reduce the relative total peak force experienced when landing the FA. These simple outcome measures could be routinely assessed to ensure successful and safe aerial landings in surfing.

Bra-body armour integration, breast discomfort and breast injury associated with wearing body armour.

This study investigated whether female soldiers experience bra integration or breast discomfort/injuries related to body armour use and whether these issues were associated with breast size. Ninety-seven Australian Defence Force female soldiers completed a questionnaire and had their breast volume assessed (range: 91-919 ml/breast) using three-dimensional scanning. Twenty-two percent (n = 21) of participants reported integration issues between their bra and body armour, 63% (n = 61) reported breast discomfort while wearing body armour and 27% (n = 26) reported experiencing a breast injury related to wearing body armour. Although bra-body armour integration was not dependent upon breast size, female soldiers with medium-large breasts reported significantly more breast discomfort and injuries when using body armour compared to participants with small breasts. These findings highlight the importance of developing body armour systems that cater to the range of breast sizes of female soldiers in order to improve bra-body armour integration and reduce breast discomfort and injury. Practitioner summary: This exploratory research provides evidence of bra integration issues, breast discomfort and breast injury experienced by female soldiers when wearing body armour. Given the growing representation of women in military organisations, strategies to alleviate these issues for female users of body armour, particularly those with larger breast sizes, are required.

Biomechanics of Breast Support for Active Women.

More systematic breast biomechanics research and better translation of the research outcomes are necessary to provide information upon which to design better sports bras and to develop effective evidence-based strategies to alleviate exercise-induced breast pain for women who want to participate in physical activity in comfort.

Training for success: Do simulated aerial landings replicate successful aerial landings performed in the ocean?

PURPOSE: Physical preparation of competitive surfers includes substantial dry-land training. It is currently unknown, however, how closely these exercises replicate surfing maneuvers performed in the ocean. This study compared the technique features displayed by surfers when landing simulated aerial maneuvers on land to critical features previously established as necessary for surfers to successfully land aerials in the ocean during competition. METHODS: Fourteen competitive surfers (age 20.6 ± 5.7 years, height 178.1 ± 9.50 cm, mass 70.6 ± 10.8 kg) were recruited to perform two variations of a simulated aerial task, a Frontside Air (FA) and Frontside Air Reverse (FAR). Joint ranges of motion (ROM), center of pressure, and apparent gaze data were collected during the landing event. Paired t tests or Wilcoxon signed-rank tests were used to identify any significant differences in the outcome variables between the two aerial tasks. RESULTS: Participants displayed 100% and 60% of the critical features associated with successfully landing a FA and FAR, respectively. In both the simulated FA and FAR, participants landed in 1.0-3.7° of dorsiflexion, moving through significantly less ankle joint ROM in the lead limb during the FAR (P < .01). Participants also displayed significantly less knee and hip ROM (P = .002-.048) while landing the FAR compared to the FA. CONCLUSION: The simulated FA and FAR tasks are appropriate training tools for surfers to replicate most of the critical features that a surfer should display to successfully land aerial maneuvers in the ocean. These tasks therefore enable surfers to practice these complex movements in a controlled environment.

Breast pain affects the performance of elite female athletes.

Although breast pain is problematic for many active women, no published research has investigated breast pain experienced by elite female athletes. This study aimed to examine the extent that mastalgia and exercise-induced breast pain affected the sporting performance of elite female athletes during training and competition. A custom-designed online survey with questions related to sport participation, as well as the frequency, severity and perceived performance effects of mastalgia and exercise-induced breast pain, was distributed to sporting organisations, coaches, medical staff and teams/clubs throughout Australia. Five hundred and forty female athletes competing nationally or internationally across 49 different sports participated in the survey. Sixty-three percent of respondents reported experiencing breast pain associated with their menstrual cycle and 33% reported that this pain worsened during activity. Forty-four percent of athletes reported experiencing exercise-induced breast pain during training or competition. Both types of breast pain were also reported to negatively affect sporting performance (20% and 32%, respectively). Mastalgia associated with the menstrual cycle and exercise-induced breast pain should be acknowledged as potential problems affecting the sporting performance of elite female athletes. Awareness around the impact of breast pain and the development and implementation of breast pain management strategies are essential for this population.

Essential Skills for Superior Wave-Riding Performance: A Systematic Review.

Forsyth, JR, Riddiford-Harland, DL, Whitting, JW, Sheppard, JM, and Steele, JR. Essential skills for superior wave-riding performance: A systematic review. J Strength Cond Res 34(10): 3003-3011, 2020-To successfully and safely perform surfing maneuvers, surfers and their coaches need to know how to perform each maneuver correctly. Although some components of the sport are well understood, evidence-based recommendations in the scientific literature on how to perform surfing skills are sparse. The aim of this article was to systematically review the body of literature pertaining to discrete wave-riding skills and characteristics that are associated with the ability of surfers to successfully perform them. Searches of PubMed, SCOPUS, SPORTDiscus with Full-text, and Web of Science were undertaken in January 2019, to identify the most appropriate literature, with secondary searches of reference lists used to create a greater pool of possible articles. The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P). Ten studies deemed appropriate for review captured data from 299 surfers, who were predominantly competitive (78.3%) and male (58.2%). The average Down and Black Quality Index of the articles was 76.3 ± 8.4%, with these articles focusing on the "pop-up" and landing skills. Performance indicators, such as isometric push-up peak forces, force-plate derived and in-water time to pop-up, relative peak forces generated when landing and time-to-stabilization, were all shown to be related to the physical characteristics of surfers and could affect the ability of surfers to successfully ride a wave. Findings from the studies included in this review suggest that the pop-up and landing exhibit trainable qualities that coaches and athletes can use to improve surfing performance.

Breast and torso characteristics of female contact football players: implications for the design of sports bras and breast protection.

This study aimed to provide normative data characterising the breast size, breast position and torso size of female contact football players. 117 AFL, Rugby League, Rugby Union and Rugby 7s players attended a single testing session where a three-dimensional scan was taken of their naked breasts and torso. Dimensions relevant to the design of sports bras and breast protective equipment were then calculated from the scans. Several breast and torso characteristics of female contact football athletes differed to measurements reported for females in the general population and amongst the contact football codes. Designers and manufacturers of sports bras or breast protective equipment should consider the specific breast and torso dimensions of female contact football players to maximise the fit, comfort and efficacy of these garments. Practitioner summary: Using three-dimensional scanning, this study characterised the breast and torso size and shape of 117 female contact football players. These normative data should be used to improve the fit and comfort of sports bras and breast protective equipment for female contact football players.

Rescheduling Part 2 of the 11+ reduces injury burden and increases compliance in semi-professional football.

Although the 11+ program has been shown to reduce injuries in sub-elite football, program compliance is typically poor, suggesting that strategies to optimize delivery are necessary. This study investigated the effect of rescheduling Part 2 of the three-part 11+ program on program effectiveness. Twenty-five semi-professional football clubs were randomly allocated to either a Standard-11+ (n = 398 players) or P2post group (n = 408 players). Both groups performed the 11+ program at least twice a week throughout the 2017 football season. The Standard-11+ group performed the entire 11+ program before training activities commenced, whereas the P2post group performed Parts 1 and 3 of the 11+ program before and Part 2 after training. Injuries, exposure, and individual player 11+ dose were monitored throughout the season. No significant between group difference in injury incidence rate (P2pos t vs Standard-11+ = 11.8 vs 12.3 injuries/1000 h) was observed. Severe time loss injuries > 28 days (33 vs 58 injuries; P < .002) and total days lost to injury (4303 vs 5815 days; P < .001) were lower in the P2post group. A higher 11+ program dose was observed in the P2post (29.1 doses; 95% CI 27.9-30.1) versus Standard-11+ group (18.9 doses; 95% CI 17.6-20.2; P < .001). In semi-professional football, rescheduling Part 2 of the 11+ program to the end of training maintained the effectiveness of the original 11+ program to reduce injury incidence. Importantly, rescheduling Part 2 improved player compliance and reduced the number of severe injuries and total injury burden, thereby enhancing effectiveness of the 11+ program.

The Occurrence, Causes and Perceived Performance Effects of Breast Injuries in Elite Female Athletes.

Female breasts are vulnerable to direct blows or frictional injuries during sport; however, little research has investigated breast injuries experienced by female athletes. This study aimed to investigate the occurrence, causes and perceived performance effects of breast injuries in elite female athletes across a wide range of sports. A custom-designed survey was distributed to female athletes aged over 18 years who were competing nationally or internationally in their chosen sport. The survey included questions about breast injuries sustained during training and competition and any perceived performance effects of these injuries. 504 elite female athletes from 46 different sports completed the survey. 36% of participants (n = 182) reported experiencing breast injuries and 21% (n = 37) perceived that their breast injury negatively affected their performance. Contact breast injuries were reported by significantly more athletes involved in contact or combat sports and by athletes with larger breasts or a higher body mass index. Frictional breast injuries were reported by significantly more older athletes or those with larger breasts. Less than 10% of participants who experienced breast injuries reported their injury to a coach or medical professional and only half used any prevention strategies. Athletes, coaches and medical professionals associated with women's sport need to be made aware of the occurrence and potential negative effects of breast injuries. It is critical to normalise conversations around breast health so that athletes can be encouraged to report and, when necessary, receive treatment for breast injuries. Further research is also required to better understand factors that affect breast injuries in sport in order to develop evidence-based breast injury prevention strategies.

Effects of age and body mass index on breast characteristics: a cluster analysis.

Limited research has quantified variation in the characteristics of the breasts among women and determined how these breast characteristics are influenced by age and body mass. The aim of this study was to classify the breasts of women in the community into different categories based on comprehensive and objective measurements of the characteristics of their breasts and torsos, and to determine the effect of age and body mass index on the prevalence of these breast categories. Four breast characteristic clusters were identified (X-Large, Very-ptotic & Splayed; Large, Ptotic & Splayed; Medium & Mildly-ptotic; and Small & Non-ptotic), with age and BMI shown to significantly affect the breast characteristic clusters. These results highlight the difference in breast characteristics exhibited among women and how these clusters are affected by age and BMI. The breast characteristic clusters identified in this study could be used as a basis for future bra designs and sizing systems in order to improve bra fit for women. Practitioner summary: This original research provides evidence for bra designers and manufacturers on the diverse breast characteristics exhibited by women within the population and the significant effect that both body mass index and age have on the breast characteristic clusters. Future bra designs should consider the variation in breast characteristics among women. ABBREVIATIONS: BMI: Body Mass Index; UBCC: Under-bust chest circumference.

How do we fit underground coal mining work boots?

Acceptable footwear fit, particularly width, is subjective and vaguely quantified. Proper shoe fit is important because it affects both comfort and the potential to prevent injury. Although mismatches between the feet of underground coal miners and their internal boot dimensions are known, no research has been undertaken to determine the impact of these mismatches on worker perceptions of fit, comfort and pain. This study aimed to quantitatively assess mining work boot fit relative to underground coal miners' subjectively rated work boot fit and comfort, reported foot problems, lower limb pain and lower back pain in order to develop evidence-based work boot fit recommendations. Traditional footwear fitting methods based predominantly on foot length are insufficient for underground coal mining-specific footwear. Instead, fit at the heel, instep and forefoot must be considered when fitting underground coal mining work boots, in conjunction with the traditional length measurement.Practitioner summary: Underground coal miners report their work boots fit but are uncomfortable. This study assessed actual fit relative to perceived fit, comfort, foot problems, lower limb pain and lower back pain of 197 miners. Fit at the heel, instep and forefoot must be considered when fitting mining work boots.