class: center, middle, inverse, title-slide .title[ # Phase II: Using Our Toolbox ] .subtitle[ ## Module 7: Beach Muslces ] .author[ ### Dr. Christopher Kenaley ] .institute[ ### Boston College ] .date[ ### 2021/10/30 ] --- class: inverse, top # In class today <!-- Add icon library --> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.14.0/css/all.min.css"> .pull-left[ Today we'll .... - Kick off Module 7 - Introduce/Review basic muscle physiology - Consider experimental procedures - Modeling data ] .pull-right[ ![](https://born2invest.com/wp-content/uploads/2023/05/image-53.png) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ - Force-Length Relationship - Cross-bridge theory predicts variable force over a range of lengths - Often omit the effect of velecity, another important parameter ] .pull-right[ ![](https://getbacktosport.com/wp-content/uploads/2020/01/Screenshot-2020-01-20-at-16.36.46.png) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ ### Central questions * What length results in peak force? * Is length at peak force always the same under different conditions? ] .pull-right[ ![](https://www.thieme-connect.de/bilder/sportsmed/200803/s0329sm02) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .center[ ![](https://sports-science.ajinomoto.co.jp/en/wp-content/uploads/sites/2/2020/09/theme_04_01.jpg) <br> ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ - Biceps brachii - Flexes lower arm ] .pull-right[ ![](https://openoregon.pressbooks.pub/app/uploads/sites/42/2018/07/Range-300x262.png) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ - Biceps brachii - Flexes lower arm - Forms 3rd order lever ![](https://i.stack.imgur.com/bmW9f.png) ] .pull-right[ ![](arm.gif) Fun R code can be found [here](https://gist.github.com/ckenaley/924171571a73874384a6aaaef93e372b). ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ ### Module 7 Question: Does eccentric fatigue shift length at peak force? ] .pull-right[ ![](arm.gif) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ - Use arm angle as proxy for length - Force (torque, really) at palm during maximal voluntary contractions (MVCs) - Fortunately TA=FL relationship in human arm system ![](https://www.nfpt.com/wp-content/uploads/Muscle-Moment-Arm.jpg) ] .pull-right[ ![](arm.gif) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ ### Module 7 Question: Does eccentric fatigue shift length at peak force? Protocol: - measure F of isometric MVCs at different angles - eccentrically fatigue biceps with book bag - measure F of isometric MVCs at different angles ] .pull-right[ ![](https://www.thieme-connect.de/bilder/sportsmed/200803/s0329sm02) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ ### Module 7 Question: Does eccentric fatigue shift length at peak force? Protocol: - measure F of isometric MVCs at different angles - eccentrically fatigue biceps with book bag - measure F of isometric MVCs at different angles ] .pull-right[ ![](https://bcorgbio.github.io/class/90deg.jpg) A gainiometer ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ ### Module 7 Question: Does eccentric fatigue shift length at peak force? Protocol: - measure F of isometric MVCs at different angles - eccentrically fatigue biceps with book bag - measure F of isometric MVCs at different angles ] .pull-right[ ![](https://bcorgbio.github.io/class/grip.jpg) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ ### Module 7 Question: Does eccentric fatigue shift length at peak force? Protocol: - measure F of isometric MVCs at different angles - eccentrically fatigue biceps with book bag - measure F of isometric MVCs at different angles ![](https://europe1.discourse-cdn.com/arduino/original/4X/6/9/1/691061a469d331747a1019e72d52ae08400071a5.jpeg) pick up today/tomorrow ] .pull-right[ ![](https://www.lollette.com/image/cache/catalog/sensor/dyly-103-1100x1100.jpg) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ Review: Load Cell Basics - metal shape strains - so do wires - voltage along circuit changes due to changes in resistance - Ohms law: `$$V=I*R$$` ![](https://en.wikipedia.org/wiki/File:Wheatstone_bridge.jpg) ] .pull-right[ ![](https://upload.wikimedia.org/wikipedia/commons/3/3b/Strain_gauge_deformation.jpg) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ Module 7 data - Many TA curves - One for each angle (x10) for each experiment (control + fatique) - 20 curves for each student ![](https://www.nfpt.com/wp-content/uploads/Muscle-Moment-Arm.jpg) ] .pull-right[ ![](https://www.researchgate.net/profile/Roger-Eston/publication/11657943/figure/fig1/AS:277342216835076@1443134945570/The-relationship-between-torque-and-joint-angle-in-children-h-and-adults-r.png) ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles .pull-left[ Module 7 data - Many TA curves - One for each angle (x10) for each experiment (control + fatique) - 20 curves for each student ![](https://www.nfpt.com/wp-content/uploads/Muscle-Moment-Arm.jpg) ] .pull-right[ ```r print(p) ``` ![](3140_f23_10-30_files/figure-html/unnamed-chunk-3-1.png)<!-- --> ] --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles Fitting polynomials, e.g., 2nd order `$$Y=aX^2+bX+c$$` where `$$a<0$$` Use of `R`'s` poly()` .... ```r library(MuMIn) poly.m2 <- lm(normF~poly(ang,2)) #second order poly.m3 <- lm(normF~poly(ang,3)) #third order poly.m4 <- lm(normF~poly(ang,4)) #fourth order AICc(poly.m2,poly.m3,poly.m4) #the 3rd order model fits best ``` ``` ## df AICc ## poly.m2 4 -43.90316 ## poly.m3 5 -39.60496 ## poly.m4 6 -49.47748 ``` --- class: inverse, top <!-- slide 1 --> ## Module 7: Beach Muscles ```r #define 1000 angles from our range x.pred <- seq(45,157.5,length.out = 1000) #predict the force using 1000 angles normF.pred <- predict(poly.m3,newdata = data.frame(ang=x.pred)) qplot(ang,normF)+ geom_point(aes(x=x.pred,y=normF.pred),col="red")+ geom_point(aes(x=x.pred[which.max(normF.pred)], y=normF.pred[which.max(normF.pred)]), size=5,col="blue") ``` ![](3140_f23_10-30_files/figure-html/unnamed-chunk-5-1.png)<!-- -->