Another single track ride today....
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I did a small amount of single track last month. I don't enjoy it as much as just racing down the trail.
https://www.relive.cc/view/v1vjkpEGnJO2023 Honda CB500X
2017 Honda CRF250 L ABS
"Where you stand depends on where you sit"
Rufus E Miles JR.Comment
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I built a bicycle shed for my youngest daughter a few years back. This summer, a young skunk took to sleeping in it next to a bike wheel. Friendly. Never sprayed.
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Last warm day of fall, 2022. Blacklick Creek Bicycle Trail
Attached FilesLast edited by wildbears; 11-11-2022, 03:12 PM.Comment
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Greyster Dogs and Mitochondria.
"All of our pets survived for thousands of years in the wild without any help from us, and this has led them to develop astonishing athletic abilities which we sometimes take for granted. As greyster dogs and endurance champ tortoises.
Dog scootering uses one or more dogs to pull a human riding an unmotorized scooter. Greysters are a naturally-athletic breed that can run at 20 miles per hour for five miles while handling these carriages. No other animal can run at this speed, exerting this power, and expending this energy for so long. So, what's their secret? Greysters' stride length can be a staggering 16 feet and they are super efficient at absorbing and using oxygen. Greyster dogs have nearly twice the mitochondria inside their cells than humans."
And now for the human application. Endurance training can increase the number of our intracellular mitochondria (specifically within our skeletal muscle cells).
See:
https://www.documentaryarea.tv/video/Athletes/
https://www.sciencedaily.com/release...1102132208.htmComment
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Of course, humans, probably starting with Australopithecus Africanus ran down their prey, too. Humans are made for long distance running. 5-10-20 hours at a stretch, a human can stay in "zone 1" for a really long time. A person in top shape can pretty well run a horse to death. The same with zebras, giraffes, elephants and about any other game animal you can think of. Dogs may have actually been "man's best friend" because of their ability to keep up with the chase.
On the other hand, man's top speed is just slow to middling. BUT, we can go 0 to max pretty darn quick - quick enough to get to a tree or other safe haven before being dragged down. -
Humans can actually chase a cheetah down on foot. Chasing down herd animals is more difficult. An experiment decades ago had a long distance runner trying to chase down an antelope. Their defense was to scatter initially and then regroup, often on a hilltop. This made it difficult for the hunter to continuously chase the same antelope. -
Another reason, besides endurance, humans can run down prey is the extensive sweat glands that cover most of our bodies. Horses have even more sweat glands and humans come in second. Other primates are up there too. But most animals cool by panting or getting in mud or water.
The ability to sweat allows continuous pursuit of prey when it is hot whereas prey animals overheat if forced to keep running in the heat.
It may follow then, in extreme heat, a human could run down a Greyster.
As for Neanderthals, they were likely ambush predators more suited to short sprints due to their stocky and muscular builds.Last edited by wildbears; 11-28-2022, 08:53 AM.
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Gained a lot of respect for mountain cyclists today. I was able to do 5 miles but had to get off the bike and walk about a dozen times. Other times I was scootering with one foot off the pedals and used as an outrigger. Lots of dry leaves on the trail made it very slippery with the back wheel coming around multiple times when braking down hill.
More Cowbell: https://www.youtube.com/watch?v=ppmlsv0XV9Y
(From the Chestnut Ridge Park website.)Last edited by wildbears; 11-21-2022, 09:23 PM.Comment
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Hyperventilation and high intensity exercise.
Some have suggested hyperventilating before a steep hill climb or a sprint. It has also been suggested for before a weight lifting set.
It would be interesting to know if it increases endurance and strength by building up and/or increasing mitochondria in muscle (cardiac and skeletal).Comment
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Rode about 20 miles yesterday on the local trail thru town. Saw about two dozen deer, crossing or grazing next to the trail. One was a 10 point buck close to the trail with about four does nearby. The buck took a "don't mess with me" stance when passed.
Cold but a great sky as the sun went down. And maybe for the first time, I realized that dusk and dawn were lasting longer going into winter.
Last edited by wildbears; 12-01-2022, 06:32 PM.Comment
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Apparently the time of year is a factor in the eastern US for observing great sunsets. In late fall and winter the normal weather patterns in the eastern US usually result in a clearer lower atmosphere and this enhances sunsets. As far as dusk is concerned, it is actually shorter in the winter than in the summer but not by much. However, dusk is shortest at the spring and fall equinoxes. So my observation that dusk was getting longer was good when compared to the fall equinox. It will shorten again as we approach the spring equinox and then lengthen towards the summer solstice.Last edited by wildbears; 12-01-2022, 06:27 PM.
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Today's ride...much warmer but still cool. That's ice, not waves.
Last edited by wildbears; 11-25-2022, 05:43 PM.Comment
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Rides this week...
The single tract follows along the edge of these bluffs. No room for error.
That's an old horse-drawn wagon with wood-spoked and iron-hoop-rimmed wheels. It's behind the spring-fed well.Last edited by wildbears; 12-01-2022, 06:20 PM.Comment
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Length of Twilight (see a previous post)
With my limited understanding of astronomy, I had to do some reading and found this info.
Twilight is longest at the solstices and shortest at the equinoxes. "A (.....) way to see this is to look at the circles that the Sun makes at different declinations (angles north or south of the equator). The biggest circle is when the Sun is at the celestial equator, which corresponds to the equinoxes. Since the Sun needs to complete its circle in 24 hours regardless of how big the circle is, the Sun's daily motion will be fastest near the equinoxes and so twilight will be the shortest then. Comparing the two solstices, the main difference is that in summer the Sun doesn't get that far below the horizon before it turns around and starts to rise. Its vertical motion at night is thus very slow. That makes the twilight longest in the summer." [https://astronomy.stackexchange.com/...t-the-equinox]
Last edited by wildbears; 12-02-2022, 08:58 AM.Comment
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This is exactly right, Wildbears. We live in Oklahoma where we can clearly see the sun at sunset, with a great view of the entire horizon. We have for many years taken our children (now adults) to see both solstices and the equinoxes. It is really stunning how much the sun moves horizontally as it descends. We have established points on the horizon to mark the suns passage.
When near the equator, the opposite effect is obvious. When I was at a Pacific beach in Costa Rica, it was as if someone turned the lights out at sunset. The sun just went straight down over the horizon - and ta-dah - it was full dark. -
Tyson, So are you the one that's been putting up all those pyramids and stones?
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The ever changing length of twilight
Our Earth was originally rotating on its axis at a 90 degree angle to the sun (0 degrees tilt). As such, a planet would be without seasons and twilight would never change its duration as viewed from a fixed location on its surface.
While most are aware of this, our axial tilt and the moon are the result of a collision. A collision with Earth's twin orbital sister, Theia. Formed at the same time as Earth, Theia was the smaller of the twins and swung around the sun in the same orbit as the uncompleted Earth. Eventually the two collided and the larger Earth was formed. And it is hypothesized that this collision resulted two moons that had not previously existed. The lower of these moons either crashed into the now larger Earth or into the other moon and was absorbed. This left our current moon to orbit in isolation.
The first collision also resulted in Earth being knocked off of its 0 degree rotational axis to the current 23.5 degrees. Which resulted in seasonal variation in the Earth's direction toward the sun depending on its rotation about the sun.
And, as posted previously, this constantly changing direction of facing the sun constantly changes the length of twilight.
Last edited by wildbears; 12-07-2022, 04:44 PM.Comment
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Arterial stiffness of lifelong Japanese female pearl divers
From the physiological standpoint, each diving maneuver evokes the diving reflex, a complex cardiorespiratory response to water immersion (19). The diving responses are initiated by apnea and consist of sympathetically mediated peripheral vasoconstriction and a dramatic increase in arterial blood pressure (6). The resultant stimulation of arterial baroreceptors produces vagally induced bradycardia (5, 12). These hemodynamic changes are accelerated by cooling of the faces in the cold sea and/or hypoxia in prolonged breath holding. The diving bradycardia is fairly substantial getting reduced to 50% of the resting heart rate and persists despite the vigorous underwater swimming performed by Ama (https://journals.physiology.org/doi/....1962.17.2.184).
#198.1
955i commented
When I was considerably younger, I could swim underwater for two lengths of a 25-yard pool. We always hyperventilated before before the challenge. Whether it actually helped or not, there is no way of knowing.
#198.2
wildbears commented
Ha! Did the same.
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Cold Weather Insoles & Rain Covers
OEM removed to provide more toe room....Comment
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