Introduction to Sports Biomechanics: Analysing Human Movement ...

INTRODUCTION TO SPORTS BIOMECHANICS
110
(c) Keep repeating this for other datasets, until you are able to sketch the angular
velocity and acceleration graphs without reference to either the figures in the
section on ‘The geometry of angular motion’ or the answers on the website.
I must stress that analysis of such movement patterns is an essential skill for all
movement analysts, whether they approach such a pattern qualitatively or quantitatively.
Although these time-series movement patterns are less familiar to you than
videos of sports movements, they are far simpler, so persevere with this. Then
persevere some more: it will pay great dividends if you become any kind of movement
analyst.
Hint: If you are struggling with this task, you may wish to reread the section on
‘The geometry of angular motion’ (pages 93–6); once you have completed this task,
compare your answers with those on the book’s website.
3 Describe the coordination sequences of the angle–knee and angle–hip joint
couplings in Figures 3.13(b) and (c). Indicate the points on the figures that
correspond to coordination changes (similar to points ‘a’ to ‘g’ in Figure 3.13(a)).
Indicate also whether the joints are in-phase or anti-phase in each region of the
diagram (as, for example, for regions ‘a’ to ‘b’ and ‘g’ to ‘a’ in Figure 3.13(a)) –
assume for this purpose that ankle plantar flexion is in-phase with knee and
hip extension. Count the number of changes in coordination between the two
joints during one running stride; how many of them are from in-phase to antiphase
or vice versa, and how many are from in-phase to in-phase or from
anti-phase to anti-phase? Note that the points in Figures 3.13(b) and (c) at
which coordination changes will not necessarily be the same as those in Figure
3.13(a); however, point ‘a’ and an anticlockwise progression are common to all three
figures.
Hint: You should study in detail the description of Figure 3.13(a) in the subsection
on ‘The coordination of joint rotations – angle–angle diagrams’ (pages 96–103)
before undertaking this task.
For Study tasks 4 to 7, download and save a walking-to-running Excel file from
the book’s website (for one runner). Successful completion of these four study tasks
is absolutely crucial if you want to become a competent movement analyst, so do
persevere.
4 By selecting the relevant columns from the Excel file, plot time-series graphs for
the hip, knee and ankle angles for both walking and running. Comment on any
observable differences between the movement patterns for walking and running.
Hint: You may wish to reread the section on ‘The geometry of angular motion’
(pages 93–6) and to consult the examples on the book’s website before undertaking
this task.
5 By selecting the relevant columns, plot angle–angle diagrams for the hip–knee and
ankle–knee couplings for each activity. Comment on any observable differences
between the coordination patterns for walking and running, such as whether the
number of changes in coordination for the same joint coupling during one stride
differs between the two forms of locomotion.
Hint: You may wish to reread the subsection on ‘The coordination of joint rotations