Comparative Investigation of Foot Blood Flow Dynamics: A Study of the Anterior and Posterior Tibial Arteries in the Sitting vs. Standing Positions

Optimal blood circulation is crucial to perform activities of daily living and for living a healthy life. For example, insufficient blood flow to the foot contributes to the development of foot pathology such as plantar fasciopathy. An unshod simulation of tight and narrow shoes showed decrease blood flow to the foot. PURPOSE: This study investigated if there was a significant decrease in blood flow to the foot via the anterior and posterior tibial arteries when an unshod person transitions from sitting to standing. METHODS: Nine individuals participated in this pilot study (age=24.7±4.4, weight=72.7kg±8.8, height=1.8m±0.07). For the sitting position, participants sat on a platform while blood flow volume measurements were taken simultaneously of the anterior and posterior tibial arteries using ultrasound pulse wave. For the standing measurements, the participants stood on the platform and the same measurements were taken. A period of three minutes after standing was implemented before standing measurements were taken to ensure that blood flow adjusted to the new position. A paired t-test was used to compare sitting to standing differences within the participants. RESULTS: In the anterior tibial artery, average volume flow changed from 4.88 ml/min (sitting) to 2.76 ml/min (standing), a 43.4% drop in blood flow (p\u3c0.01). In the posterior tibial artery, volume flow decreased from an average of 5.01 ml/min to 3.69 ml/min, a decrease of 26.3% (p\u3c0.05). Total reduced blood flow between the two arteries decreased from 9.89 ml/min to 4.88 ml/min, a 50.6% drop (p\u3c0.01). CONCLUSION: This study demonstrates a simple change in position significantly impacts blood flow to the foot. This suggests further research is needed to determine if there is an additive effect of footwear on this observed decrease in blood flow that may contribute to an increase incidence rate of plantar fasciopathy. This finding additionally provides rationale to investigate what mechanism the body uses to overcome positional-related decreases in blood flow

Individuals Wearing Cleats Transitioning from Sitting to Standing Demonstrate a Significant Decrease in Blood Flow to the Foot

Plantar fasciopathy is a common foot condition with 10% prevalence in the general population. Plantar fasciosis (a type of fasciopathy) is considered a degenerative condition associated with cell death due to a lack of blood flow. Narrow, tight footwear, such as cleats, have been implicated as a potential contributing factors for the development of plantar fasciopathy and their direct influence on blood flow to the foot is currently unknown. PURPOSE: To investigate blood flow change in the anterior and posterior tibial arteries between sitting and standing in a cleated foot. METHODS: Eight individuals participated in this pilot study (weight=70.5 kg±12.9, height=1.8m±0.17). The participant put cleats on both feet, with a perceived tightness of 5/10 or greater on a VAS scale. Blood flow volume measurements of the anterior and posterior tibial arteries were taken simultaneously using pulse wave ultrasound, while the participant sat on a platform. These measurements were then repeated in the standing position on the same platform. Blood flow was measured in the dominate shod foot. A paired t-test was used to compare sitting to standing conditions within participants. RESULTS: In the anterior tibial artery, average volume flow changed from 6.25 ml/min (sitting) to 2.6 ml/min (standing), a 58% drop in blood flow (p=0.09). In the posterior tibial artery, volume flow decreased from an average of 11.25 ml/min to 3.95 ml/min, a decrease of 65% (p\u3c0.05). Total reduced blood flow between the two arteries decreased from 8.75 ml/min to 3.28 ml/min, a 63% drop (p\u3c0.05). CONCLUSION: There appears to be an important alteration of blood flow to the foot in individuals wearing cleats as they transition from a sitting to standing position. If this decrease in blood flow were to persist while wearing cleats, it may help explain the development of plantar fasciopathy observed in individuals wearing narrow, tight footwear

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements