Measuring the Biomechanics and Energetics of Curved vs. Traditional Treadmills in Female Adults

Manufacturers claim that exercising on a curved treadmill will promote, proper running mechanics and up to 30% more calories compared to a traditional motorized treadmill. If the curved treadmill is able to increase metabolic costs while minimizing load on the user, it may prove to be beneficial to all populations. Exercising on a compliant, curved surface may prove to be especially beneficial to special populations where the onset of pain limits the duration of cardiovascular exercise. If the curved treadmill can minimize joint stress, it may prolong the length of time that someone with special considerations may be able to exercise. PURPOSE: The purpose of this study is to examine whether a non-motorized curved (aka curved) treadmill will provide a biomechanical or energetic advantage compared to a motorized flat (aka traditional) treadmill. We hypothesize that, when compared to the traditional motorized treadmill, the non-motorized treadmill will result in 1) significantly higher caloric expenditure and VO2% value and a 2) significant increase in forward trunk flexion under all testing conditions. METHODS: Participants wore a breathing mask connected to the Oxycon Mobile system to measure the metabolic cost of all each movement pattern. Additionally, participants were outfitted with reflective markers in order to capture 3-dimensional kinematic data. Participants were instructed to perform at their self-selected pace and afterwards randomly instructed to change speed to 15% above, and 15% below their self-selected walking and running pace. In total, there were four 15-minute blocks of exercise, each of which were separated by a 10-minute block of rest to ensure adequate recovery. RESULTS: There was not a significant increase in the amount of trunk flexion under any of the conditions between the curved and traditional treadmill. There was a significant increase in the amount of energy expenditure from the traditional treadmill to the curved treadmill. CONCLUSION: While still largely uninvestigated, curved treadmills are becoming more popular as a modality of cardiovascular exercise. Our findings suggest that female athletes may benefit from using curved treadmills over traditional treadmills because of the increased caloric expenditure and aerobic capacity but further research needs to be conducted in order to assess the viability as a safe option with respect to musculoskeletal structures

Initial Reaction Probability and Dynamics of Ozone Collisions with a Vinyl-Terminated Self-Assembled Monolayer

The gas-surface reaction dynamics of ozone with a model unsaturated organic surface have been explored through a series of molecular beam scattering experiments. Well-characterized organic surfaces were reproducibly created by adsorption of C=C-terminated long-chain alkanethiols onto gold, while the incident molecular beams were created by supersonic expansion of ozone seeded in an inert carrier gas to afford control over collision energy. Time-of-flight distributions for the scattered molecules showed near complete thermal accommodation of ozone for incident energies as high as 70 kJ/mol. Reflection-absorption infrared spectroscopy, performed in situ with ozone exposure, revealed that oxidation of the double bond depends significantly on the translational energy of O 3. For energies near room temperature, 5 kJ/mol, the initial reaction probability (γ 0) for the formation of the primary ozonide was determined to be γ 0 = 1.1 × 10 -5. As translational energy increased to 20 kJ/mol, the reaction probability decreased. This behavior, along with a strong inverse relationship between γ 0 and surface temperature, demonstrates that the room-temperature reaction follows the Langmuir-Hinshelwood mechanism, requiring accommodation prior to reaction under nearly all atmospherically relevant conditions. However, measurements show that the dynamics transition to a direct reaction (analogous to the Eley-Rideal mechanism) for elevated translational energies. © 2011 American Chemical Society