Lab 1_Linear Kinematics _sprint analysis

Lab 1: Sprint Analysis The purpose of this lab is to (1) gain practice computing linear kinematics of walking and running, and (2) observe how humans manipulate stride length, and stride rate to increase speed of locomotion. APPLICATIONS: Kinematic features of running have been examined by biomechanists for such purposes as improving performance and investigating injury mechanisms. Since running is an important fundamental movement, it will be used in this lab to study linear kinematics. In this lab, linear motion will be assumed during running although angular motion is also accruing. PART 1: Critique Sprint Performance EQUIPMENT 40 m running course (cones), 1 tape measure, stop watch, and computer and calculators (used after data collection) PROCEDURES A person will sprint 40 meters while having his/her run timed. Timers will be located at each 5 m of the marked 40 m course. The timers will give time when the runner crossed that zone. Strides in each zone will also be counted during the run. It is easiest to count steps (round to the nearest 0.5 step) and divide by 2. Use the excel document provided to input the accumulative time and the strides per zone. Then, use the time and stride data to calculate/fill in all other columns on the document. Once the data table is complete, build two graphs (description below) in excel. After your graphs are build, copy each graph and past them in this word document. Next, answer the discussion questions. It is easiest to answer the questions on the document. After the questions have been answered, upload this document with your graphs and excel data copied into this document on Canvas. Step #1: Graphs Based on the information from your excel table, construct two graphs to describe your results. Each graph should be properly labeled (axes labels with proper units) with a descriptive title. Be sure to include a legend identifying each line of the graph. Copy and paste your graphs from the excel sheet into this document. Graph #1 - Kinematics Analysis Graph : Display zone time on Y1, zone velocity and zone acceleration on Y2. Plot accumulative time on the horizontal axis (X).

1 2 3 4 5 6 7 8 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 Sprint Numbers Zone Velocity Zone time Zone acceleration Accumalative time Velocity and Acceleration Zone Time Graph #2 - Stride Analysis Graph : Plot Stride Rate for each zone on Y1 and Stride Length for each zone on Y2. Plot accumulative displacement on the horizontal axis (X). 1 2 3 4 5 6 7 8 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 Stride Stride length Strude Rate Accumalative Displacement Stride Length Stride rates Step #2: Discussion Questions – answer the following questions below. 1. Review the kinematics analysis graph (Graph #1) by reviewing each line. For each variable in the graph (zone time, zone velocity, and zone acceleration), identify when each variables has the highest values. Do the highest values occur more in the first half or second half of the sprint? Next, identify why each variable is highest in these areas of the

Strides # Disp Displ Time Vel per per per No. Rate Lg           5 m 5 m 5 m per per p           Zone Zone Zone Zone Zone Zo     (S) (SR) (S (S/s) (m (m) (m) (s) (m/s) (s) (m/s) (m/s/s) St r 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0. 1 5 5 1.58 3.16 1.58 3.16 2.00 2.00 0.40 2 5 10 2.10 4.77 0.52 9.62 3.16 1.75 0.35 3 5 15 2.85 5.26 0.75 6.67 0.65 1.50 0.30 4 5 20 3.10 6.45 0.25 6.60 0.70 2.00 0.40 5 5 25 3.87 6.46 0.77 6.49 0.01 1.75 0.30 6 5 30 4.66 6.44 0.79 6.33 0.03 1.50 0.30 7 5 35 5.00 7.00 0.34 14.71 1.65 1.50 0.30 8 5 40 5.38 7.43 0.38 13.15 1.13 1.50 0.30 AVERAGE 3.57 5.87 0.67 8.34 1.17 1.69 0.33 PART 2: Speed and Stride Parameters EQUIPMENT Cones, tape measure, and stop watch Useful Equations Equation one (1) The magnitude of average walking/running (i.e., gait) velocity (v ) may be calculated by dividing displacement (d) by time(t): v = d t Equation two (2) When motion is rectilinear, velocity and speed can also be calculated as the product of stride length (SL) times the stride rate (SR). Stride length is displacement divided by the number of strides (heel off to heel strike for one leg). Stride rate is the total number of strides taken divided by the total time. Thus, another equation to determine gait velocity is expressed as: v = SL X SR

PROCEDURES 1. Observe two walking, two jogging and one sprinting trial (6 trials total) over a 20 m displacement at progressively increasing velocities. The five conditions are defined as: a. walk b. fast walk c. jog d. fast jog e. sprint 2. A total time and total number of strides taken (to nearest half-stride) should be recorded for all conditions on the next page. Students are encouraged to review SL and SR examples from lecture. Complete and turn in the data collection table, calculations, running profile and answers to the questions. 3. Work in groups of about 5 to collect the data. The following descriptions correspond to responsibilities of each person in the group (a-e; a = one student’s responsibility, b= another student’s responsibility, etc.) a. Stand at the start of the 20 m test zone and drop your hand when the runner enters the zone so the timer can start the stopwatch b. Stand at the end of the 20 m test zone and time the runner (time to the nearest 0.5s). c. Stand at a distance and count the number of steps (i.e., every footfall) the runner takes in the 20 m test zone (count to the nearest 0.5 step). d. Record data (number of steps and time). e. Subject see description above f. These jobs are rotated until all five students have completed their own trials Data collection sheet Walk Fast walk Jog # of strides ________ # of strides ________ # of strides ________ Total time ________ Total Time ________ Total time ________ Fast Jog Sprint # of strides ________ # of strides ________ Total time ________ Total time ________ Data collection table 1. Calculate the magnitude of average velocity (using equations 1 and 2 in the appropriate columns), stride length, and stride rate for each trial. 2. In the last column, convert average velocity (calculated with equation 2) to miles per hour (mph); 1mph = .45m/s. Condition Displ. # Time Vel. (1) SL SR Vel . (2) Vel .

1 2 3 4 5 0 0.5 1 1.5 2 2.5 3 3.5 0 0.5 1 1.5 2 2.5 Stride Stride Length Stride Rate Ambulatory Condition m/Strides Strides/sec Step #2 - Discussion Questions: Answer the questions below. 1. Based on the data from this lab, how did stride length and stride rate change as velocity increased? As stride length increases, we see a increase in velocity as well. 2. Consider the stride length and stride rate of an elite sprinter running near 10m/s. Based on the graph below and your data, compare the stride lengths and stride rates of an elite sprinter to your own stride lengths and stride rates. What changes could be made to improve your performance so it is more like an elite sprinter? Would you change your stride rate, stride length, or both? I feel that I could increase my explosiveness from the start of the sprint, and try to throw my arms more throughout the whole sprint. I see sprinters using as much momentum as they can to increase their own velocity and force production. I would try to increase my stride length to limit tiring out my body. Elite sprinters tend to have huge long strides that is comfortable for their body.