Comparison of bone mineral density between male masters runners and cyclists

Click on the link to access this abstract at the publisher's website.For maintenance of bone mass during adulthood, it is commonly recommended to participate in relatively high level weight-bearing exercise. Weight-bearing exercise includes aerobic activities such as jogging or activities that produce high ground reaction forces such as jumping. Cycling is a popular form of aerobic exercise for older adults due to the reduced impact on the weight-bearing joints. However, due to the unloaded nature of cycling, some data suggest that bone mineral density at clinically important sites is reduced in cyclists. PURPOSE: To compare areal bone mineral density (aBMD) of the lumbar spine and non-dominant proximal femur between male masters runners and male masters cyclists. METHODS: Eight male masters runners (mean ± SD, age: 58.9 ± 4.4 yrs, height: 175.3 ± 6.9 cm, weight: 75.1 ± 14.3 kg) and eight male masters cyclists (mean ± SD, age: 63.8 ± 5.9 yrs, height: 176.8 ± 5.8 cm, weight: 76.8 ± 8.3 kg) underwent a dual energy x-ray absorptiometry (DXA) scan for assessment of aBMD of the non-dominant proximal femur (total hip and femoral neck) and lumbar spine (L1-L4) as well as percent body fat (%BF), and bone free lean body mass (BFLM). Data were analyzed using Independent Samples t-tests with an alpha level of 0.05. RESULTS: There were no significant differences in age, height, or weight between groups. Compared to masters cyclists, masters runners did not show any significant differences in %BF (16.8 ± 3.6 vs. 16.0 ± 3.3%, p=0.679), BFLM(59.1 ± 9.1 vs. 61.2 ± 7.6, p=0.618), lumbar spine aBMD (1.041 ± 0.130 vs. 0.991 ± 0.062, p=0.346), total hip aBMD (0.989 ± 0.152 vs. 0.917 ± 0.079, p=0.257), or femoral neck aBMD (0.816 ± 0.111 vs. 0.730 ± 0.074, p=0.090). CONCLUSION: Our preliminary findings suggest that male masters cyclists and runners do not differ in aBMD. However, our current findings are likely influenced by the small sample size which will be addressed in the near future

Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo

Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software

Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo

International audienceIntermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200 M⊙ and effective aligned spin 0.8 at 0.056 Gpc−3 yr−1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpc−3 yr−1.Key words: gravitational waves / stars: black holes / black hole physicsCorresponding author: W. Del Pozzo, e-mail: [email protected]† Deceased, August 2020