Can the recent sex-specific evolutions in elite running performances be attributed to advanced footwear technology?

Recent improvements in elite running performances across all distances have been largely attributed to the introduction of advanced footwear technology (AFT), which features a curved and stiff plate working synergistically with a new generation of midsole foams demonstrating enhanced resilience and compliance. These recent improvements appear to be considerably more pronounced in women's events, highlighted by improvements in road racing world records by an average of 3.7% (range: 2.6%-5.2%) compared to mean progressions of 1.5% (range: 1.3%-1.9%) in the same men's events. Although there is a growing body of research investigating the mechanisms underpinning running performance enhancements derived from AFT, there remains no explanation for potential sex-based differences in their benefits. We overview the currently available evidence and highlight why the recent direction of AFT research provides a barrier to progress by focusing primarily on male athletes. We subsequently provide our perspective on why women may be benefiting from the new generation of shoes more than men, suggest potential mechanisms leading to hypotheses that need to be further investigated in upcoming studies, and finally propose that factors outside of footwear innovation may have concurrently driven the recently observed performance evolutions.

Sex differences in human running performance: smaller gaps at shorter distances?

Human, but not canine or equine running performance, is significantly stratified by sex. The degree of stratification has obvious implications for classification and regulation in athletics. However, whether the widely cited sex difference of 10%-12% applies equally to sprint and endurance running events is unknown. Here, different determining factors for sprint (ground force/body mass) versus endurance performance (energy supply and demand) and existing trends, led us to hypothesize that sex performance differences for sprint running would increase with distance and be relatively small. We quantified sex performance differences using: 1) the race times of the world's fastest males and females (n = 40 each) over a 15-year period (2003-2018) at nine standard racing distances (60-10,000 m), and 2) the 10-m segment times of male (n = 14) and female (n = 12) athletes in World Championship 100-m finals. Between-sex performance time differences increased with sprint event distance (60 m-8.6%, 100 m-9.6%, 200 m-11.0%, 400 m-11.7%) and were smaller than the relatively constant mean (12.4 ± 0.3%) observed across the five longer events from 800 to 10,000 m. Between-sex time differences for the 10-m segments within the 100-m dash event increased throughout spanning 5.6%-14.2% from the first to last segment. We conclude that sex differences in sprint running performance increase with race and running distance.NEW & NOTEWORTHY Sex performance differences for sprint running bursts are small (<6%), but widen as the distance sprinted increases (range: 5.6%-14.2%). The distance dependency identified here for sprinting differs from the prevailing literature view of between-sex performance differences for the human running of 10%-12% regardless of distance. The variable sprint margins observed reflect the relative performance benefits shorter females have for brief, acceleration-dependent efforts versus those taller males have for longer steadier-speed sprint efforts.

Artificially long legs directly enhance long sprint running performance.

This comment addresses the incomplete presentation and incorrect conclusion offered in the recent manuscript of Beck et al. (R. Soc. Open Sci. 9, 211799 (doi:10.1098/rsos.211799)). The manuscript introduces biomechanical and performance data on the fastest-ever, bilateral amputee 400 m runner. Using an advantage standard of not faster than the fastest non-amputee runner ever (i.e. performance superior to that of the intact-limb world record-holder), the Beck et al. manuscript concludes that sprint running performance on bilateral, lower-limb prostheses is not unequivocally advantageous compared to the biological limb condition. The manuscript acknowledges the long-standing support of the authors for the numerous eligibility applications of the bilateral-amputee athlete. However, it does not acknowledge that the athlete's anatomically disproportionate prosthetic limb lengths (+15 cm versus the World Para Athletics maximum) are ineligible in both Olympic and Paralympic track competition due to their performance-enhancing properties. Also not acknowledged are the slower sprint performances of the bilateral-amputee athlete on limbs of shorter length that directly refute their manuscript's primary conclusion. Our contribution here provides essential background information and data not included in the Beck et al. manuscript that make the correct empirical conclusion clear: artificially long legs artificially enhance long sprint running performance.

Smoke-Free Ordinances and Policies Protect Youth, but Ordinances Appear to Have Little Impact on Non-Combustible Tobacco Use.

Smoke-free ordinances and policies protect youth from exposure to secondhand smoke (SHS) and cigarette use. This study investigated whether smoke-free ordinances also protect youth from the use of other tobacco products. We compared the prevalence of SHS exposure, cigarette smoking, cigar smoking, smokeless tobacco use, and e-cigarette use among high school students living in a municipality with or without a smoke-free ordinance and in homes with and without smoke-free policies. Data were analyzed using the 2017 Mississippi Youth Tobacco Survey (n = 1923). Smoke-free ordinances were found to be associated with lower prevalence of SHS exposure (41.9% vs. 51.5%), cigarette smoking (5.1% vs. 11.4%), and cigar smoking (7.2% vs. 10.9%). There were no differences in smokeless tobacco use (6.6% vs. 6.5%) or e-cigarette use (11.2% vs 12.1%). Smoke-free homes were associated with lower prevalence of SHS exposure (38.0% vs 74.6%), cigarette smoking (4.8% vs. 17.6%), cigar smoking (6.4% vs. 16.4%), smokeless tobacco use (4.9% vs. 13.2%), and e-cigarette use (9.6% vs. 19.5%), p < 0.05 for all comparisons. The results suggest that smoke-free ordinances and policies protect against exposure to tobacco smoke and use of combustible tobacco products, but smoke-free ordinances do not protect from smokeless tobacco and e-cigarette use. Tobacco-free, rather than smoke-free, ordinances might offer more protection.

Electronic Cigarettes in Mississippi: Issues Facing Healthcare Providers and Policy Makers.

BACKGROUND: Electronic cigarettes (e-cigarettes) are currently unregulated nicotine delivery products, and use is increasing among youth and young adults in the U.S. Little is known about use in Mississippi. DESIGN/METHODS: Surveys assessed e-cigarette use among Mississippi adolescents and adults. UMMC provided data on reported cases of e-cigarette poisonings. RESULTS: From 2010 to 2014, current e-cigarette use increased from 0.6% to 6.7% among middle school students, from 1.2% to 10.1% among high school students, and from 0.2% to 6.8% among adults. There were no reported cases of e-cigarette poisonings in 2010, 2011, or 2013. There was one case in 2012. Cases increased to 26 in 2014, and 17 cases were reported in 2015. CONCLUSION: E-cigarette use has increased substantially. E-cigarettes expose users and bystanders to harmful chemicals and cancer-causing compounds. Regulation of e-cigarettes at the local, state, and federal levels is needed to address the clear harms to non-smokers.

Tobacco Use Trends among Mississippi Youth following the 1997 Settlement of Mississippi's Medicaid Lawsuit and Subsequent Tobacco Prevention Initiatives.

BACKGROUND: Mississippi has implemented several programs and policies to reduce youth tobacco. This study examines trends in youth tobacco use and compares current prevalence rates for cigarettes, cigars, smokeless tobacco, and e-cigarettes. DESIGN/METHODS: The Youth Tobacco Survey is a self-administered survey of a multi-stage sample of public high school students. RESULTS: Cigarette and cigar smoking decreased from 1998 to 2014. However, current use of smokeless tobacco did not change and e-cigarette use has increased. Currently, there are no significant differences in the prevalence of cigarette, cigar, smokeless tobacco, or electronic cigarette use. CONCLUSION: The state has successfully decreased cigarette and cigar smoking. However, smokeless tobacco use has not changed and e-cigarettes are becoming increasingly popular. Currently, Mississippi youth are at equal risk for cigarette, cigar, smokeless tobacco, or electronic cigarette use. Tobacco prevention efforts, clinician counseling, and policies should address each of these products rather than focus primarily on cigarettes.