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Rough Quantitative Measures. Hitting a pitched baseball scary easy Swimming race win by a length (body) win by a pool length. Scary easy one body length one pool length. Can’t respond in time Plenty of time to respond if race is 100m, fraction is 2/100 = 2% 25/100 = 25%
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Rough Quantitative Measures • Hitting a pitched baseball • scary • easy • Swimming race • win by a length (body) • win by a pool length
Scary easy one body length one pool length Can’t respond in time Plenty of time to respond if race is 100m, fraction is 2/100 = 2% 25/100 = 25% 1000m race->2.5% Translate closer to physics
Clocks and rulers • In sports as in physics, we compare performances against one another or by an objective measure. • Track and field. Rulers. .. High jump, long jump. Clocks. Measure time for 100m at one meet vs another. • Baseball homerun. 400 feet to center field fence.
Humans’ clocks and rulers • Humans have their own built in clocks and rulers. • Size of body • heart beat • response time • health • size
Some experiments • Catch the ruler. • This sets one of the human clock times. • (0.25 seconds) • Griffey: “See the ball, hit the ball” • Flight time is .45 seconds for major league pitch.
rates as a way of organizing knowledge • Who’s faster? • 100m 9.8 sec • 200 m 19.2 sec • speed = distance/time = 100/9.8 = 10.2m/s • speed = 200/19.2 = 10.4 m/s • about 2% faster for the longer distance!
locker room vs lab • Doers vs eggheads • How does theory of running help runners? • How much does practice help?
physics is experiments • The basis for any scientific law is experiment. • Not because the principle is logical • In complex situations the logic and the experiment may be unclear. • It’s sometimes helpful to break it down into components which are analyzable.
sports and human potential • We hear statements such as the 4 minute mile cannot be broken …. Then it is broken. • Is this a strike against the eggheads? • I’m not actually aware of any science behind the original claim. • How about pole vaulting higher than 5 meters?
historical sports science (or other competition) • Before the machine age, the cultivation of the living machines: humans and animals was profoundly important. • Martial arts • Use of tools. Swords, spears, bows and arrows. • Use of animals. Horses. … but much improved with better tools…saddles and stirrups.
How can physics help? • Here is a systematic philosophy for evaluating claims.
Advertising cons you into thinking you’re the one, • You can do what’s never been done, • Meanwhile life goes on all around you. • Bob Dylan, ~1960.
Jumping shoes eg. • Do the $150 sneakers help you be like Mike? • Float through the air • Go above the hoop • Why do high jumpers use thin unsprung track shoes?
How can knowledge help in response time? • We imagine a model of how the body works . Verify it by experiment. • Try it out. • Model is that the eye sees, the brain interprets and sends a signal to the muscle , which then acts. • People are pretty much the same in the total response time.
Training • Training the eye-brain helps. After a few trials, most people plateau out • Shorten the transmission time of signal • shorten the muscle action time. • Measurements of isolated nerves and muscles show that these are pretty much constant. Nerves: speed • Muscles response time.
We can get an edge • Nerve conduction has constant speed. • Speed = distance/time. • Time = distance/speed. • To decrease time, we need to decrease distance. • Tests show that the time to catch something shortens to about 0.18 sec. • 25% faster
In sports we need more. • We want to hit the ball with high bat speed. • Requires body to propel bat to high speed. • Good batters are very muscular and quick. • Physics behind this? Kinematics and dynamics.
