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Stretching and injury prevention: an obscure relationship. - PubMed - NCBI
Sports involving bouncing and jumping activities with a high intensity of stretch-shortening cycles (SSCs) [e.g. soccer and football] require a muscle-tendon unit that is compliant enough to store and release the high amount of elastic energy that benefits performance in such sports. If the participants of these sports have an insufficient compliant muscle-tendon unit, the demands in energy absorption and release may rapidly exceed the capacity of the muscle-tendon unit. This may lead to an increased risk for injury of this structure. Consequently, the rationale for injury prevention in these sports is to increase the compliance of the muscle-tendon unit. Recent studies have shown that stretching programmes can significantly influence the viscosity of the tendon and make it significantly more compliant, and when a sport demands SSCs of high intensity, stretching may be important for injury prevention. This conjecture is in agreement with the available scientific clinical evidence from these types of sports activities. In contrast, when the type of sports activity contains low-intensity, or limited SSCs (e.g. jogging, cycling and swimming) there is no need for a very compliant muscle-tendon unit since most of its power generation is a consequence of active (contractile) muscle work that needs to be directly transferred (by the tendon) to the articular system to generate motion. Therefore, stretching (and thus making the tendon more compliant) may not be advantageous. This conjecture is supported by the literature, where strong evidence exists that stretching has no beneficial effect on injury prevention in these sports.
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november 2017 by nhaliday
How to estimate distance using your finger | Outdoor Herbivore Blog
1. Hold your right arm out directly in front of you, elbow straight, thumb upright.
2. Align your thumb with one eye closed so that it covers (or aligns) the distant object. Point marked X in the drawing.
3. Do not move your head, arm or thumb, but switch eyes, so that your open eye is now closed and the other eye is open. Observe closely where the object now appears with the other open eye. Your thumb should appear to have moved to some other point: no longer in front of the object. This new point is marked as Y in the drawing.
4. Estimate this displacement XY, by equating it to the estimated size of something you are familiar with (height of tree, building width, length of a car, power line poles, distance between nearby objects). In this case, the distant barn is estimated to be 100′ wide. It appears 5 barn widths could fit this displacement, or 500 feet. Now multiply that figure by 10 (the ratio of the length of your arm to the distance between your eyes), and you get the distance between you and the thicket of blueberry bushes — 5000 feet away(about 1 mile).

- Basically uses parallax (similar triangles) with each eye.
- When they say to compare apparent shift to known distance, won't that scale with the unknown distance? The example uses width of an object at the point whose distance is being estimated.

per here: https://www.trails.com/how_26316_estimate-distances-outdoors.html
Select a distant object that the width can be accurately determined. For example, use a large rock outcropping. Estimate the width of the rock. Use 200 feet wide as an example here.
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august 2017 by nhaliday
Three muscle stretching techniques are frequently described in the literature: Static, Dynamic, and Pre-Contraction stretches (Figure 2).

Static stretching is effective at increasing ROM.

Unfortunately, however, static stretching as part of a warm-up immediately prior to exercise has been shown detrimental to dynamometer-measured muscle strength19–29 and performance in running and jumping.30–39 The loss of strength resulting from acute static stretching has been termed, “stretch-induced strength loss.”3 The specific causes for this type of stretch induced loss in strength is not clear; some suggest neural factors,31,40 while others suggest mechanical factors.19,23

In general, it appears that static stretching is most beneficial for athletes requiring flexibility for their sports (e.g. gymnastics, dance, etc.). Dynamic stretching may be better suited for athletes requiring running or jumping performance30 during their sport such as basketball players or sprinters.

Stretching has not been shown to be effective at reducing the incidence of overall injuries.88 While there is some evidence of stretching reducing musculotendinous injuries,88 more evidence is needed to determine if stretching programs alone can reduce muscular injuries.3
study  health  fitness  fitsci  evidence-based  running  embodied  sports  survey  summary  biomechanics  endurance  embodied-pack 
august 2017 by nhaliday

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