Introduction.  Motion involves changing place or position with respect to a  reference point.  Human locomotion can be described as general motion. General motion is a combination of  translatory and angular movements as one is changing places with respect to some reference point.   Orientation concepts such as planes, axes, and changes in center of gravity (whole body and/or body segments) help us describe motion.  In addition, motion can be studied in terms of distance and direction from a starting point, how fast one (or an object) is moving, and any change in speed that might occur.  The study of kinematics involves describing motion in terms of displacement, velocity, and acceleration.  There is no consideration of forces that cause or modify the motion in the study of kinematics.  In this laboratory experience you will (1) become familiar with units of measurement in biomechanics; (2) be introduced to key kinematic terms;  (3) calculate velocity and acceleration of two individuals involved in a sprint event; and (4) plot the intra-kinematic dynamics of a sprint event.

Section 1.  Units of Measurement.

Units of measurement utilized in the field of biomechanics are expressed in terms of space, time, and mass.  There are two systems of measurement, U.S. system and metric. The following table illustrates  some common units of measurement in their U.S. and metric equivalents.

Unit Metric System       U.S. Equivalents  and, conversion equivalents

Length

centimeter (cm)
meter (m) = 100 cm
kilometer (km) = 1000m inch(in)

foot(ft)
mile (mi) = 5280 ft 1 in = 2.54 cm

1 cm = 0.3937 in
1 ft = 0.305 m
1 m = 3.28 ft
1 mi = 1.609 km
1 km = 0.621 mi
___________________________
Area
square meter (100 cm2)

square foot (144 in2) 1 in2 =  6.45 cm2

1 cm2 = 0.155 in2
____________________________

Volume
cubic cm (cm3)
liter (1000 cm3)

cubic in (in3)
quart (57.75 in3) 1 qt = 0.946 liter

1 liter = 1.06 qt
1 in3 = 16.39 cm3
1 cm3 = 0.06 in3
___________________________
Mass

kilogram (kg) slug (32 lb) 1 kg = 0.068 slug
1 slug = 14.6 kg

Force (weight) newton (0.012 kg)

pound (lb) 1 lb = 0.045 kg

1 kg = 2.21 lb
1 N = 0.225 lb

Time second  for both metric and US

Source: Kinesiology, by Luttgens & Hamilton, 9th ed. Brown & Benchmark, c. 1997
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Section 3.  Kinematic Analysis of Sprinting

A. Calculation of average velocity. Table 1  below was derived from time analysis of a 100 meter sprint at a  track and field meet.  Using this data, calculate the average velocity for each 10 meter displacement. You may record your answers in Table 2.  Show all your work.

Table 1. Distance, average displacement and accumulative time at each 10 meters of the 100 meter dash run for Carl Lewis (CL) and for Ben Johnson (BJ) during the 1987 World Championship Track Meet.
 
 

Distance    Average Displacement       Time for CL    Time for BJ
(Meters)         (Meters)                         (Seconds)      (Seconds)
   10.0                 10.0                                 1.94            1.85
   20.0                 10.0                                 2.96            2.85
   30.0                 10.0                                 3.91            3.79
   40.0                 10.0                                 4.77            4.67
   50.0                 10.0                                 5.56            5.55
   60.0                 10.0                                 6.42            6.43
   70.0                 10.0                                 7.36            7.39
   80.0                 10.0                                 8.22            8.25
   90.0                 10.0                                 9.05            9.11
  100.0                10.0                                 9.90           10.10
 
 

Table 2.  Average velocity during each 10 meter displacement of the 100 meter dash run for Carl Lewis and Ben Johnson during the 1987 World Championship Track Meet. ( answers should read  to two decimal places; e.g., 9.85 m/s).

Distance      Average Velocity           Average Velocity
(Meters)      CL (meters/sec)              BJ (meters/sec)

  10

  20

  30

  40

  50

  60

  70

  80

  90

 100

B. Calculate the average acceleration of each sprinter for:
                                                                               CL                                 BJ

a. The first ten meters

b. Between 10-20 meterss

c. Between 20 and 30 meters

d. Between 30 and 40 meters

e. Between 40 and 50 meters

f.  Between 50 and 60 meters

g. Between 60 and 70 meters

h. Between 70 and 80 meters

i. Between 80 and 90 meters

j. Between 90 and 100 meters.
 

C.  Intra-race velocity dynamics. Graph  (as discussed in class) the intra-race velocity values for each sprinter. What intra-race velocity dynamics resulted in Carl Lewis outperforming Ben Johnson?  Provide a description of what happen early in the race, mid-way, and toward the end of the race. (Show graph and provide a one paragraph description)