Do plantar flexor muscle structure and function contribute to medial tibial stress syndrome in long-distance runners? A case report.

Two long-distance runners developed MTSS (male age=26.3 years, female age=47.5 years) after baseline assessment of plantar flexor muscle structure and function and spatiotemporal running variables. B-mode ultrasound and lean leg girth characterized plantar flexor muscle structure. Hand-held dynamometry and a single-leg heel raise to failure protocol characterized plantar flexor muscle function. Finally, spatiotemporal running variables were determined during a treadmill protocol. The two runners who developed MTSS demonstrated less plantar flexor strength and endurance capacity than published comparative control data and marked variability in muscle structure. Reduced plantar flexor strength and endurance capacity were thought to contribute to an impaired ability to resist tibial bending moments during midstance due to earlier muscle fatigue. Earlier muscle fatigue could, in turn, contribute to increased tibial bending moments and MTSS development. Therefore, assessing plantar flexor muscle strength and endurance might help to identify athletes at risk of developing MTSS.

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.

Understanding the relationship between surfing performance and fin design.

This research aimed to determine whether accomplished surfers could accurately perceive how changes to surfboard fin design affected their surfing performance. Four different surfboard fins, including conventional, single-grooved, and double-grooved fins, were developed using computer-aided design combined with additive manufacturing (3D printing). We systematically installed these 3D-printed fins into instrumented surfboards, which six accomplished surfers rode on waves in the ocean in a random order while blinded to the fin condition. We quantified the surfers' wave-riding performance during each surfing bout using a sport-specific tracking device embedded in each instrumented surfboard. After each fin condition, the surfers rated their perceptions of the Drive, Feel, Hold, Speed, Stiffness, and Turnability they experienced while performing turns using a visual analogue scale. Relationships between the surfer's perceptions of the fins and their surfing performance data collected from the tracking devices were then examined. The results revealed that participants preferred the single-grooved fins for Speed and Feel, followed by double-grooved fins, commercially available fins, and conventional fins without grooves. Crucially, the surfers' perceptions of their performance matched the objective data from the embedded sensors. Our findings demonstrate that accomplished surfers can perceive how changes to surfboard fins influence their surfing performance.

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.

What do male netball players want in their footwear? Design recommendations for netball-specific shoes for men.

With the increasing professionalisation of men's netball and the high prevalence of foot-related problems and pain, manufacturers must develop shoes with the correct ergonomic design to meet the unique needs of male netball players. This study aimed to determine what factors men consider when selecting a netball-specific shoe and what design features they want in an ideal netball-specific shoe. 279 amateur, sub-elite and elite male netball players completed a 38-question online survey about their footwear habits and preferences. Support was the most influential factor when men selected a netball-specific shoe. A wider toe-box, more durable upper and outsole, and added cushioning and support in the midsole and insole were preferred fit, form and function features for an ideal netball-specific shoe. We recommend that manufacturers develop a range of netball-specific shoes based on the foot dimensions, playing demands and preferences of male netball players to meet men's fit and functionality requirements.

Changes to breast structure and function across a woman's lifespan: Implications for managing and modeling female breast injuries.

BACKGROUND: Female breasts change throughout a woman's life in response to fluctuating hormonal influences. Individuals managing active women and those modeling female breasts must understand these structural and functional changes across a female's lifespan because these changes affect breast injuries sustained by women. METHODS: We initially review female breast structure and function and then describe how breast structure changes across a woman's lifespan. Key studies about direct contact and frictional breast injuries are then summarized. Limitations of current breast injury research, gaps in knowledge about breast injuries incurred by specific populations, and the lack of breast injury models are also highlighted. FINDINGS: With minimal anatomical protection, it is unsurprising that breast injuries occur. Although research about breast injuries is scant, direct contact during blunt force trauma to the anterior chest wall and frictional breast injuries have been reported. There is a lack, however, of research documenting the incidence and severity of breast injuries incurred in occupational settings and in women's sports. Therefore, to design effective breast protective equipment, we recommend research to model and investigate the mechanisms and forces involved in breast injuries, particularly injuries sustained during sport. INTERPRETATION: This unique review summarizes how female breasts change over a woman's life span, with implications for breast injuries sustained by females. Knowledge gaps about female breast injuries are highlighted. We conclude by recommending research required to develop evidence-based strategies to improve how we classify, prevent, and clinically manage breast injuries sustained by females. SUMMARY: We review changes to the breast across a woman's lifespan, highlighting implications for managing and modeling female breast injuries.

Pioneering women of the International Society of Biomechanics.

The presence of successful female role models in biomechanics can encourage girls, women, and other underrepresented groups in STEM fields to pursue and remain within the discipline. It is, therefore, vital that women and their contributions to the field are publicly visible and recognized across all areas of professional biomechanical societies, such as the International Society of Biomechanics (ISB). Enhancing the visibility of female role models in biomechanics can act to mitigate current bias and stereotyping in the discipline by broadening what it looks like to be a biomechanist. Unfortunately, women are not publicly visible in many aspects of ISB activities, and finding details of women's contributions to ISB, particularly during ISB's formative years, is challenging. This review article aims to raise the visibility of female biomechanists, particularly women in ISB leadership positions who have helped shape the Society over the past 50 years. We summarize the unique backgrounds and contributions of some of these pioneering women who blazed pathways for other female biomechanists. We also recognize the women who were charter members of ISB, women who served on ISB Executive Councils and the portfolios they have held, women who have received the highest awards of the Society, and women awarded a Fellowship of ISB. Practical strategies to enhance women's participation in biomechanics also are presented so that women can thrive and progress in ISB leadership positions and awards and, in turn, serve as positive role models to encourage girls and women to pursue and remain within this unique discipline.

Increasing women's participation in biomechanics through National Biomechanics Day events.

Science, technology, engineering and mathematics (STEM) occupations represent one of the broadest gender gaps in any professional field, with women and girls grossly underrepresented in STEM education and careers, particularly engineering and biomechanics. Factors such as bias, stereotyping, and a lack of female role models can significantly influence women's and girls' decisions to enter and remain in the field of biomechanics. A critical first step in increasing the number of female biomechanists is to create early opportunities for girls to explore biomechanics. To address this, international initiatives, such as National Biomechanics Day (NBD), have been developed to expand the awareness, influence, and impact of biomechanics by engaging young people in school biomechanics programs. The Biomechanics Initiative, the official sponsor of NBD, offers grant programs aimed at empowering women to host an NBD event designed to promote biomechanics to girls and women in an immersive, interactive, and engaging manner. In 2021, Biomechanics Research Laboratory (BRL) Ph.D. student Maddison Kirk was a recipient of the grant program. In this paper we describe the BRL NBD event, which involved 20 female athletes from diverse backgrounds, demonstrating to them how biomechanics can be used to assess their physical fitness and performance. Female biomechanists and research assistants running the NBD event acted as female role models to participants, increasing the visibility of women in biomechanics and, in turn, helping to address current bias and stereotyping in STEM. By diversifying biomechanics and ensuring STEM fields are representative of the society in which we live, we can advance the field of biomechanics both nationally and internationally.

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.

Do the Footwear Profiles and Foot-Related Problems Reported by Netball Players Differ Between Males and Females?

INTRODUCTION: We explored the footwear profiles and foot-related problems reported by netball players and whether these differed between males and females. METHODS: Two thousand nine hundred and twenty-five amateur, sub-elite and elite netball players (men n = 279; women n = 2646; age 26.4 ± 10.0 years) completed a custom-designed online survey with questions related to netball experience, current netball footwear habits and history of foot-related problems. Footwear profiles and foot-related problems were considered in logistic regressions against sex and competition level to ascertain significant relationships (p < 0.05) and predictive values (odds ratio). RESULTS: Although 80.4% of respondents reported wearing netball-specific shoes, females were 13.2 times more likely to wear netball-specific shoes than males. Foot-related problems and foot pain were reported by 84.3% and 56.8% of netball players, respectively; with blisters, ankle sprain/strains and calluses being most common. Although women were significantly more likely to suffer from foot-related problems than men, males were significantly more likely to believe their foot pain was caused by the footwear they wore for netball. CONCLUSION: The high prevalence of foot-related problems and pain reported by all netball players suggests that the shoes players are currently wearing for netball are not meeting the requirements of players, particularly regarding fit, comfort and functionality. As male netball players have significantly different footwear profiles to female players, men are likely to require netball-specific footwear that differs to the netball-specific shoes designed for female players.

Women with larger breasts are less satisfied with their breasts: Implications for quality of life and physical activity participation.

INTRODUCTION: Although low breast satisfaction has been associated with a range of potential negative health implications, little is known about key factors that influence breast satisfaction across the lifespan. This study aimed to determine the impacts of age, body mass and breast size on breast satisfaction and how breast satisfaction impacts psychosocial and sexual well-being-related quality of life outcomes and physical activity behaviours. METHODS: Three hundred and forty-five women (age range: 18.1-83.7 years) had their body mass (kg), standing height (cm) and breast volume (ml) measured. A 13-item questionnaire comprising the Breast-Q and Active Australia Survey was used to assess breast satisfaction, quality of life outcomes and participation in physical activity. RESULTS: Breast satisfaction was influenced by breast size, such that women with larger breasts were less satisfied with their breasts compared to their counterparts with smaller breasts. Greater breast satisfaction was associated with improved psychosocial and sexual well-being-related measures of quality of life, and time spent participating in physical activity. CONCLUSION: Interventions to improve breast satisfaction among women across the breast size spectrum should be encouraged in public health initiatives to better engage and encourage positive health behaviours and reduce potential adverse health implications.

Long-term lessons learned in biomechanics: 2021 Geoffrey Dyson Lecture.

After recently accepting an offer to retire, I have taken the opportunity to reflect on long-term lessons learned throughout my 40-year career as a biomechanist in academia. These lessons formed the basis of my 2021 Geoffrey Dyson Lecture and are summarised within this article. Most of these lessons are targeted at early career researchers, although my recent transition into retirement revealed some unexpected lessons that apply to senior academics. The lessons presented relate to the need to be passionate and persistent about your research, the importance of being unique and embracing failure as a mentor, as well as running with opportunities that arise. Appreciating that a career takes time to evolve, strategies to nurture a committed and supportive research team, the importance of committing to a professional society, and the need to be kind to yourself are also discussed. Why so few women receive career awards in biomechanics and when should academics retire are also addressed. I hope that highlighting lessons learned over an academic career as a biomechanist, combined with suggested practical strategies to thrive in academia, ensure academics can savour a fulfiling career in biomechanics while producing high-quality research into the future.

Effect of Torso and Breast Characteristics on the Perceived Fit of Body Armour Systems Among Female Soldiers: Implications for Body Armour Sizing and Design.

This study aimed to provide normative data characterising the torsos and breasts of female soldiers and to determine which torso and breast anthropometric measurements contributed to reports of poor body armour fit. Ninety-seven female Australian Army soldiers completed a questionnaire about their experience with current-issue body armour, including perceptions of fit. Participants also attended a single testing session where we took a three-dimensional scan of their breasts and torso and collected several anthropometric measurements to characterise their torso size and shape. Sixteen of the 22 breast and torso measurements collected were significantly related to the perceived fit of current-issue body armour systems. To improve perceptions of fit for female soldiers and, in turn, reduce movement interference, discomfort, and barriers to occupational performance, future body armour systems should cater to the wide range of female breast and torso shapes and sizes.

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.

Can smaller body armour improve thoracolumbar range of motion and reduce interference when female soldiers perform dynamic tasks?

Most female soldiers report that in-service body armour systems are too large. We investigated whether a smaller prototype body armour system could improve thoracolumbar range of motion (ROM) and reduce interference when female soldiers performed dynamic postures. 97 female soldiers completed three ROM tasks and seven dynamic postures wearing no armour, an in-service body armour system, and a smaller prototype system. Feedback on comfort of the prototype system was also obtained. Thoracolumbar ROM and dynamic posture completion were both hindered by using body armour, although the participants' performances were significantly less impeded when they wore the smaller prototype system compared to the in-service system. A smaller body armour system that is better matched to the anthropometric dimensions of female soldiers appears to improve overall fit and function. An increased range of body armour sizes and female-specific designs should be systematically explored to further enhance fit and function of body armour.

Are Leg Muscle, Tendon and Functional Characteristics Associated with Medial Tibial Stress Syndrome? A Systematic Review.

BACKGROUND: Medial tibial stress syndrome (MTSS) is a common overuse injury that lacks effective evidence-based treatment options. Reduced leg girth has been associated with MTSS development because it is hypothesised to impair the ability of the leg to modulate tibial loading generated during foot-ground contact. Measuring total leg girth, however, does not provide specific information about the structural composition or functional capacity of individual leg muscles. Consequently, uncertainty remains as to which specific muscles are compromised and contribute to MTSS development. Therefore, this paper aimed to systematically review the body of literature pertaining to how the structure and function of the leg muscles are thought to be associated with MTSS injury. METHODS: The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P). Medline, PubMed, SCOPUS, SPORTDiscus with Full-texts and Web of Science were searched until March 2021 to identify articles in which lower limb muscle structural or functional variables associated with MTSS injury were investigated. RESULTS: Seventeen studies, which were predominately case-control in design and captured data from 332 individuals with MTSS symptoms and 694 control participants, were deemed appropriate for review. The average Downs and Black Quality Assessment score was 71.7 ± 16.4%, with these articles focussing on leg girth, tendon abnormalities, muscle strength and endurance, shear modulus and neuromuscular control. Of the risk factors assessed in the 17 studies, decreased lean leg girth and higher peak soleus muscle activity during propulsion were most strongly correlated with MTSS development. Individuals with MTSS also displayed deficits in ankle plantar flexor endurance, greater isokinetic concentric eversion strength, increased muscle shear modulus and altered neuromuscular recruitment strategies compared to asymptomatic controls. CONCLUSIONS: Future prospective studies are required to confirm whether decreased lean leg girth and higher peak soleus muscle activity during propulsion are associated with MTSS development and to elucidate whether these structural and functional differences in the leg muscles between MTSS symptomatic and asymptomatic controls are a cause or effect of MTSS.

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.

Lower leg muscle structure and function are altered in long-distance runners with medial tibial stress syndrome: a case control study.

BACKGROUND: Medial tibial stress syndrome (MTSS) is a common lower leg injury experienced by runners. Although numerous risk factors are reported in the literature, many are non-modifiable and management of the injury remains difficult. Lower leg muscle structure and function are modifiable characteristics that influence tibial loading during foot-ground contact. Therefore, this study aimed to determine whether long-distance runners with MTSS displayed differences in in vivo lower leg muscle structure and function than matched asymptomatic runners. METHODS: Lower leg structure was assessed using ultrasound and a measure of lower leg circumference to quantify muscle cross-sectional area, thickness and lean lower leg girth. Lower leg function was assessed using a hand-held dynamometer to quantify maximal voluntary isometric contraction strength and a single leg heel raise protocol was used to measure ankle plantar flexor endurance. Outcome variables were compared between the limbs of long-distance runners suffering MTSS (n = 20) and matched asymptomatic controls (n = 20). Means, standard deviations, 95 % confidence intervals, mean differences and Cohen's d values were calculated for each variable for the MTSS symptomatic and control limbs. RESULTS: MTSS symptomatic limbs displayed a significantly smaller flexor hallucis longus cross-sectional area, a smaller soleus thickness but a larger lateral gastrocnemius thickness than the control limbs. However, there was no statistical difference in lean lower leg girth. Compared to the matched control limbs, MTSS symptomatic limbs displayed deficits in maximal voluntary isometric contraction strength of the flexor hallucis longus, soleus, tibialis anterior and peroneal muscles, and reduced ankle plantar flexor endurance capacity. CONCLUSIONS: Differences in lower leg muscle structure and function likely render MTSS symptomatic individuals less able to withstand the negative tibial bending moment generated during midstance, potentially contributing to the development of MTSS. The clinical implications of these findings suggest that rehabilitation protocols for MTSS symptomatic individuals should aim to improve strength of the flexor hallucis longus, soleus, tibialis anterior and peroneal muscles along with ankle plantar flexor endurance. However, the cross-sectional study design prevents us determining whether between group differences were a cause or effect of MTSS. Therefore, future prospective studies are required to substantiate the study findings.