Biomechanics-sprint start kinematics repor

guidelinesforreport1 xSE571Practical12019-2020AdditionalWrite-upInformation411 xSE571Practical12019-20FINALDATASETFORALLGROUPS11 GenericGuidanceforBiomechanicsLabReports2019-2011 x

Module SE

71: Biomechanics of Sport and Exercise
Practical 1: Sprint Start Kinematics in Faster and Slower Sprinters
Additional Write-up Information

The practical 1 handout given out during the data collection practical session provided a very brief introduction to the sprint start topic area and information on collecting the kinematic data of a sprint start. This document contains some useful information to get you thinking about how best to interpret and present the data.

Firstly, it is essential that you carry out a thorough review of the literature related to the kinematics of sprinting. Your review of the literature should not only aid your understanding of what kinematic parameters have been investigated and the results and findings that have been reported, but also assist you in becoming familiar with the layout of biomechanical journal articles, particularly the manner in which the data is presented and discussed.

Probably the overriding principle related to the practical write-up is that you should base the content and style of each section of your write-up on what is typically found within biomechanical journal articles. Please note that an abstract is not required. In terms of presenting your results, it is important that you consider the best format to present the data. Use published literature as a guide towards the ideal formats to adopt for presentation of results and for the manner in which the results are discussed and the main aspects focussed upon.

Please note that for this practical the hip marker will be used to approximately represent the centre of mass (CM). Therefore when comparing the data collected to the literature, this practical will compare hip marker linear data to CM linear data within the literature. The term “block clearing” or similar is used within the literature, this practical did not use starting blocks, however, the term can still be used, which corresponds to the “instant” of front foot clearance.

Data for lab report

The data for the lab report will use data from a total of TWELVE (or more) subjects collated from different SE571 practical groups. The data for the other subjects will be provided on studentcentral > SE571 > Study Materials > Practicals > Practical 1 once collated. The sharing of data across practical groups will occur in order for practical groups to have sufficient subject numbers to aid the statistical testing of the results. Please note that subject names MUST NOT be used within the practical report, refer to subjects 1, 2, etc.

The Lab Report Data excel file will contain the collated subject data obtained during the practical which was entered into the Practical 1 excel file and e-mailed to

s.h.mills@brighton.ac.uk

The Lab Report Data excel file will also contain some simple formulae to automatically calculate the key kinematic parameters which have been discussed within the literature, e.g. block pushing time, range of ankle joint dorsi-flexion during first stance, flight and contact time of the first stance. It is recommended that you click on the cells in the calculated data columns to view the formulae, to assist you in creating these formulae in future biomechanical studies.

As stated above, use published literature as a guide towards the ideal formats to adopt for presentation of results and for the manner in which the results are discussed and the main aspects focussed upon. The following section briefly summarises the kinematic data presented in some sprint start articles.

Kinematic Data Presented within the Literature and Guidance for Your Report

Slawinski et al, 2010

Slawinski et al collected both kinematic and kinetic data, so focus only on the kinematic data. The excel files provided do not contain data for the “on your marks position”, so you are unable to present and discuss this data. Tables

– 7 are used to present their data for five different “critical instants”: “set position”, “pushing phase”, “block clearing”, “first step”, and “second step”. All tables list the mean and standard deviation (SD) data, as well as indicate with symbols which results are statistically significantly different (independent samples Student’s t-test) between the two groups of sprinters, i.e. statistically significantly different between the elite and well-trained.

Figure 5 presents the “horizontal position of center of mass (XCM) at 5 critical positions” within a format of a column chart. Highlighting a few of the key/most significant, kinematic parameters in figure/chart format is typical within biomechanics journal articles. Notice that the statistical significance is also indicated with the use of a * symbol representing p < 0.05. Figure 6 illustrates the “velocity of the centre of mass during the pushing phase and 2 first steps” with a velocity versus time graph. This particular graph displays the group mean and SD data for both sprinter groups at every time point. You are not able to present a graph for all sprinters as you do not have all of the exported linear data excel files for all sprinters. However, you are able to present a horizontal velocity of the hip marker (represents the CM) versus time graph for your one subject, by plotting a chart within excel using the exported linear “Hip Horizontal Velocity” data. Also indicate on your figure, as shown on figure 5, the different phases of the movement, i.e. pushing phase, flight and contact phase.

Coh et al, 2017

Coh et al also collected both kinematic and kinetic data, so again only focus on the kinematic data. This article presents all of the kinematic data for both groups of sprinters, i.e. faster and slower, within one table, this being table 2. Notice that they also present the actual t-test and p values, obtained from the independent samples (unpaired) Student’s t-test used to test for statistical significance for each parameter, as well as the Cohen’s d effect size. There is no need to calculate effect the effect size, but it is essential that you test for statistical significance using the independent samples (unpaired) Student’s t-test, and present the findings from the statistical test either adopting the format used by Coh et al, or alternatively using the symbols format used by Slawinski et al. Guidance on carrying out independent samples (unpaired) Student’s t-test (which was covered on module SE426) is provided within the additional information folder: studentcentral > Practical Folder > Practical 1.

To examine the relationships between the kinematic variables of the sprint start and sprinting performance, Spearman’s correlation coefficients were calculated and presented within Table 4. This table is referred to as a correlation matrix, where relationships between all variables are presented. Typically, the researcher is more interested in simply the relationship between the kinematic variables and the performance measure, i.e. the sprint time. You may therefore only wish to present the correlation coefficients between the kinematic variables and for your study the main performance measure being the time for the shoulder to reach 2.000 metres. Table 4 has the correlation coefficients presented separately for the faster and slower sprinters. This is one approach used, however, calculating the correlation coefficients for all sprinters, regardless of the sprinter’s group, is the more common approach, as used by Ciacci et al (2017, p1273) “linear regressions (correlations) were used to examine how performance (100m sprint time) affected each kinematic variable in the whole sample of 20 sprinters”. You may therefore wish to calculate the correlation coefficients for all of your subjects together, rather than for the two different groups of fast/slow subjects. Coh et al, don’t state why they used Spearman’s correlation coefficients, rather than the more commonly used Pearson Product correlation coefficient. It may have been due to the nature of their data, e.g. non-parametric data. Presenting either correlation coefficient will be fine, but the Pearson Product correlation coefficient is more common and is the statistical test which was covered on module SE426.

With regards to the correlation coefficients, due to the subject numbers being low, the level of statistical significance could likely be low, i.e. non-statistically significant p values. However, it is probably better to focus on the strength/size of the relationship as indicated by the r-value, adopting the same approach as Coh et al, (2017, p31) which refers to the relationship as “small r = 0.1 – 0.3”, “medium r = 0.3 – 0.5”, and “large r = 0.5 – 1.0”. Bezodis et al, 2015 (see below) defined the strength of the relationship using different criteria: “moderate r = 0.3 – 0.5”, “high r = 0.5 – 0.7”, “very high r = 0.7 – 0.9”, and “practically perfect r = 0.9 – 1.0”. These criteria provide more detail and are therefore probably preferable.

Similar to Slawinski et al above, figure 2 also presents the velocity of the centre of mass throughout the sprint within a velocity versus time graph. Notice the different phases are indicated within the graph, i.e. block phase both feet in contact (red), front foot pushing (blue), flight phase (thin black), and first step and second step contact phases (red then blue). As indicated above you can present your horizontal hip velocity data for your one subject within a velocity versus time graph, by plotting a chart within excel using the exported linear “Hip Horizontal Velocity” data.

Ciacci et al 2017

Although the specific focus of the study by Ciacci et al is on comparing male and female sprinters, the study is still useful in terms of identifying the kinematic parameters they investigated and the format they adopt to present their data. Unfortunately, much of their statistical analysis is a little advanced, however, in agreement with the two previous studies mentioned above they used independent-sample Student t-tests to compare the mean values of female versus male sprinters.

Table 2 presents all of the kinematic parameters within three columns: female mean (SD), male mean (SD) and the male-female difference (95% Confidence Interval), with statistical significance indicated with the # symbol. Adding the third column, i.e. the difference value between the two groups of data, helps convey the size of the difference. The # symbol indicates whether this difference is statistically significant so possibly there is no need to also present the confidence intervals.

Bezodis et al 2015

The specific focus of the study by Bezodis et al, (not the review article), is slightly different to the above studies in that they weren’t comparing data between two data sets, e.g. male versus female, or fast versus slow, but they were focussing on the examination of relationships between specific technique variables and their performance measure, which was external power production during the block phase. As we haven’t yet covered power within the SE571 lectures, we aren’t using power as a performance measure.

The main performance measure we are using is the time taken for the shoulder to reach 2.000 metres from the start line. Other performance measures have also been used within sprint start biomechanics literature, as highlighted by Bezodis et al, 2019. These include: horizontal centre of mass (CM) block clearance velocity, instantaneous CM velocity at a specific timing point e.g. at the 5 metre mark, and block acceleration. It is possible to consider relationships to more than one performance measure, therefore CM block clearance velocity, instantaneous CM velocity at the 2 metre mark, and block acceleration data is also provided within the Lab Report Data excel file. Although these three variables have been considered measures of sprint performance within the literature, they are also kinematic variables which can contribute to the main sprint performance measure. The relationship (r-value) of these three kinematic variables in relation to the time for the shoulder to reach 2.000 metres should therefore also be investigated, along with the relationships of the other kinematic variables you have collected to the performance measure(s) as explained below. (Apologies if this last paragraph is a bit confusing, it is just quite difficult to explain whilst trying to be concise!)

Table 1 presents all of the joint or segment kinematic data within the set position and during the block phase. In addition to the group mean and standard deviation data, also presented are the correlation coefficient values (r-values) for each kinematic variable related to their performance measure (block power). The table also contains other data e.g. ICC and 90% confidence intervals, however this level of statistical analysis was not covered during SE426 so you can ignore this data. Table 2 similarly presents the group mean and standard deviation data, and the correlation coefficient values (r-values) for each kinematic variable, but now for the first flight and stance phases.

Figure 1 contains graphs of the rear and front leg angular velocity versus time for the hip, knee and ankle joints. You will notice that along the x axis times is represented as % of Stance rather than the usual time (seconds). You may wish to present a similar figure of angular velocity versus time (seconds), but for your subject only, (exported angular data from Quintic), as an example subject to illustrate how angular velocity changes with time during a sprint start. Notice that within Figure 1, the correlation coefficient relating the peak angular velocity to their performance measure has been presented as this r-value was not presented in table 1 or 2 and may be a significant variable, especially for the hip joint with r values of 0.49 (moderate, nearly high) being reported.

Results and Discussion – Some suggestions on what to focus on

Looking carefully at the data within the Lab Report Data excel file, one has to decide upon what format is best to present this data and what data is appropriate to present, i.e. figure or table, and the layout of the tables/figures. Referring to the sprint literature provides guidance on the most important data to present and different presentation approaches used, as illustrated with the four studies summarised above. There is no ONE way of presenting data!

Refer back to the practical 1 handout to remind yourself of the focus of the practical. Therefore firstly there is a need to establish if there was a difference in sprint performance for the two different levels of sprint groups, i.e. faster and slower. You will need to test for statistical significance by carrying out an ‘Independent-Samples T-test’ for the performance variable(s). A Sig. (2-tailed) value less than .05 indicates that there is a difference in sprint performance at the two different group sprint levels. But it is also important to identify which kinematic variables also differ between the two different group sprint levels. You therefore also need to test for statistical significance for the key kinematic variables that have been presented in sprint kinematics literature.

As indicated above within three of the four studies summarised, it can also be useful to examine the relationships between the variables you have collected and the main sprint performance measure, i.e. the time for the shoulder to reach 2.000 metres. Although not evident within the four papers summarised above, sometimes significant relationships are illustrated with a scatter diagram. Consider whether this would be effective if you find any significant relationships between kinematic variables and sprint performance time. It is important that you consider the best format to present the data within the results section. Use published literature as a guide towards the ideal formats to adopt.

Practical Write-up

The write-up of this practical can be your assessed piece of work and contributes to 50% of your final grade for SE571. The alternative assessed practical write-up is practical 2. Note: The assessment submission deadline is 11:00am on the 30th of January 2020.

The word guide for the write-up of 1750 words does not include references, tables, and figures. The write-up is to be written in the style of a scientific academic journal article, except it does not include an abstract. Therefore, the write up should contain Introduction, Methods, Results, Discussion, and References. Base the content and style of each section of your write-up on what is typically found within biomechanical journal articles. Please note, an abstract is not required.

The introduction should inform the reader of the purpose of the research including the theoretical framework of the research. The method section should have sufficient detail to enable replication of the study, whilst at the same time written in a concise manner. The results section should lead the reader though the results with appropriate commentary to highlight the key findings. Results should be presented using a combination of figure, table and within text. Typically, only group mean (+ standard deviation) data is presented within the results. A time trace for the linear data of the CM or for angular kinematic data of various joints of one of the subjects is often also included within a results section. Scatter diagrams to illustrate relationships between variables and performance are also sometimes included, as are also sometimes included a Pearson’s correlation matrix/table. Use the most appropriate format to best illustrate your results.

The discussion should discuss your results, not simply be a repeat of your results. You should try to explain why the results occurred, and relate your findings to the theoretical framework and to previous literature. Refer to the literature on the kinematics and if appropriate the kinetics of the sprint start to develop your discussion, ensuring all literature referred to within the write-up is accurately referenced, using the Harvard referencing format, in your reference section. Include a reference section, NOT a bibliography. Therefore, all publications included in your reference section must be referred to within your practical write-up.

IMPORTANT FINAL GUIDANCE

Finally, the 1750-word laboratory practical report is an individual piece of work. The data collection and data analysis were carried out in sub groups. It is essential that all other aspects of the written report are completed individually. It is likely that students will read similar literature, but the introduction and discussion MUST be individually written. Similarly, although the method used by all students is identical, the methods section MUST be individually written. The data provided within the Lab Report Data excel file will be identical for all students within the Practical Group, however this data needs to be presented within the report within appropriate tables and figures. These tables and figures should be individually created and the commentary of the results MUST be individually written.

It is recommended that you do not e-mail draft reports to members of your sub-group. It is good practice to discuss the writing up of the laboratory practical report and to discuss the key findings of the literature review and of the results obtained within practical 1 with fellow students, but the write-up MUST be an individual piece of work.

3
5

Module SE

71: Biomechanics of Sport and Exercise
Practical 1: Sprint Start Kinematics in Faster and Slower Sprinters
Additional Write-up Information

Data for lab report

The Lab Report Data excel file will contain the collated subject data obtained during the practical which was entered into the Practical 1 excel file and e-mailed to

s.h.mills@brighton.ac.uk

Kinematic Data Presented within the Literature and Guidance for Your Report

Slawinski et al, 2010

Coh et al, 2017

Ciacci et al 2017

Bezodis et al 2015

Results and Discussion – Some suggestions on what to focus on

Practical Write-up

IMPORTANT FINAL GUIDANCE

3
5

Sprint Start Kinematic Data – FINAL Table with

Calculated Data

Subject

Number Subject Name

Performance

Time

= Time from

GO to

Shoulder at

2.000 metres

from start line

(s)

Block

Acceleration

= HIP X velocity

at block

clearance

divided by total

block time

(m/s/s)

Set Position

Vertical Height

of HIP Above

SHOULDER

Positive = HIP

above

SHOULDER

(m)

Reaction Time

= Time from

GO to first

visible

distinctive

starting

movement

(s)

REAR

Foot Block

Time (Pushing

Time

Rear Block

[PTRB])

= Time from

first visible

distinctive
starting

movement to

REAR foot

clearance

(s)

Possible Data for Results YES YES YES YES

YES

FAST Group

1 Subject1 0.92 5.45 0.19 0.22 0.22

2 Subject2 0.97 5.02 0.16 0.16 0.20

3 Subject3 0.98 0.00 0.03 0.21 0.20

4 Subject4 0.99 4.53 0.18

0.08

0.33

5 Subject5 1.02 4.19 -0.04 0.21 0.29

MEAN 0.98 3.84 0.10 0.18 0.25

Standard Devn. 0.04 2.20 0.10 0.06 0.06

SLOW Group

6 Subject6 1.02 2.61 -0.11 0.14 0.32

7 Subject7 1.10 3.19 0.00 0.15 0.25

8 Subject8 1.13 0.00 0.00 0.23 0.25

9 Subject9 1.17 3.52 0.25 0.24 0.37

10 Subject10 1.22 2.91 -0.16 0.21 0.24

MEAN 1.13 2.45 0.00 0.19 0.29

1.58 #DIV/0! 0.08 1.41 0.16 0.05 0.06

Total Block

Pushing Time

= Time from
first visible
distinctive
starting
movement to

FRONT foot

clearance
(s)

Percentage

Pushing Time

Rear Block

[%PTRB])

Rear foot

block time

divided by total

block time

(%)

Total Block

Time

= Time from

GO to FRONT

foot clearance

(s)

First Stance

Flight Time

= Time from

front foot

clearance to

first step touch

down

(s)
First Stance

Contact Time

= Time from
first step touch

down to toe-off

(s)

Stride Time of

First Stride

= Time from
REAR foot
clearance to

first stance take-

off

(s)

Stride Length of

First Stride

Distance from

TOE in set

position to TOE

at first step

touch down

(m)

YES YES YES YES

YES

YES YES

0.45 33 0.67 0.08 0.19 0.50 1.49

0.48 31 0.64 0.01 0.24 0.53 1.43

0.46 30 0.67 0.03 0.20 0.49 1.52

0.64 46 0.72 0.01 0.29 0.61 2.05

0.56 38 0.77 0.03 0.25 0.55 2.15

0.52 35 0.69 0.03 0.23 0.54 1.73

0.08 6 0.05 0.03 0.04 0.05 0.34

0.62 42 0.76 0.04 0.23 0.57 1.660

0.58 34 0.73 0.04 0.25 0.62 1.510

0.45 37 0.68 0.06 0.16 0.42 0.000

0.64 42 0.88 0.02 0.21 0.50 1.710

0.53 32 0.74 0.02 0.22 0.53 0.000

0.56 38 0.76 0.04 0.21 0.53

0.98

0.08 4.43 0.07 0.02 0.03 0.08 0.89

Sprint Start Kinematic Data – Table 1

Video Frame No. at Significant Moments OBTAINED DURING Digitising

Block Exit STEP

Length =

Distance from

Front TOE in set

position to Rear

TOE at first step

touch down
(m)

Amount of

ANKLE

Joint

DORSI-

FLEXION

During First

Stance

Phase

(Deg)

Amount of HIP

Joint

EXTENSION

During REAR

Foot Block

Time

(Deg)

Data not

available, as

should have

been HIP angle

at REAR

FOOT

Clearance!

Distance HIP is

Ahead of TOE

at First Step

Touch Down

Negative = HIP

behind TOE

(m)

Trial

Number Subject Name

Synchron-

isation light on

(Set position)

Frame

No.

YES YES Not Available YES

0.97 27.1 -0.28 Subject1 77

0.72 7.1 -0.53 Subject2 77

0.86 28.4 -0.43 Subject3 761

1.24 57.9 -0.80 Subject4 187

1.06 10.0 -0.72 Subject5 247

0.97 26.1 -0.55 MEAN 270

0.20 20.2 0.21 Standard Devn. 284

2.510 12.3 -0.530 Subject6 121

0.700 0.8 -1.130 Subject7 168

-0.640 49.5 0.000 Subject8 267

0.730 8.5 -0.620 Subject9 377

-0.730 6.0 0.000 Subject10 356

0.51 15.4 -0.46 MEAN 258

1.32 19.48 #DIV/0! 0.48 #DIV/0! #DIV/0! 112.60

Sprint Start Kinematic Data – Table 1

Video Frame No. at Significant Moments OBTAINED DURING Digitising Semi-quantitative Data in Set Position OBTAINED IN LAB

First visible

distinctive
starting

movement

Frame No.

Rear foot
clearance
Frame No.

Front foot

clearance
Frame No.

First step touch

down Frame

No.

First step

take-off

Frame No.

Horizontal

distance of

SHOULDER

to start line

Positive = in

front, Negative

= behind

(m)
Horizontal

distance of

rear TOE

to start line

(m)
YES

99 121 144 152 171 0.03 0.76

93 113 141 142 166 0.03

1.10

782 802 828 831 851 -0.05 0.95

195 228 259 260 289 -0.10 1.04

268 297 324 327 352 0.06 1.25

287 312 339 342 366 -0.01

1.02

286 284 284 284 283 0.07 0.18

135 167 197 201 224 -0.05 –

0.97

183 208 241 245 270 -0.11 1.03

290 315 335 341 357 -0.02 0.84

401 438 465 467 488 -0.02 1.06

377 401 430 432 454 0.05 0.75

277 306 334 337 359 -0.03 0.54

116.77 117.74 115.97 115.00 113.81 0.06 0.86

Sprint Start Kinematic Data – Table 2

Semi-quantitative Data in Set Position OBTAINED IN LAB FROM Digitised Data Set Position

Vertical

distance of
SHOULDER

to start line

cross ground

level

(m)
Vertical

distance of

HIP

to start line
cross ground

level

(m)
Horizontal

distance between

rear and front

foot TOE location

(Block Spacing)

(m)
Trial
Number Subject Name
Set Position

Rear HIP

Joint Angle

(Deg)
Set Position

Rear KNEE

Joint Angle
(Deg)

YES YES YES

0.61 0.8 0.52 Subject1 64.39 113.76

0.60 0.76 0.71 Subject2 93.2 131.9

0.66 0.69 0.66 Subject3 91.8 112.1

0.64 0.82 0.81 Subject4 95.5 148.1

0.68 0.64 1.09 Subject5 138.0 45.8

0.64 0.74 0.76 MEAN 96.6 110.3

0.03 0.08 0.21 Standard Devn. 26.4 39.0

-0.55 -0.66 -0.85 Subject6 93.85 128.37

0.49 0.49 0.81 Subject7 137.47 164.54

0.64 0.64 0.64 Subject8 87 93

0.59 0.84 0.98 Subject9 93.41 160.35

0.62 0.46 0.73 Subject10

0.36 0.35 0.46 MEAN 102.9 136.6

0.51 0.59 0.74 #DIV/0! #DIV/0! 23.24 33.23

Block Phase / Block Clearance

Set Position

HIP

X Location

(m) (This

data is 0.000

due to new

software used

this year)

Set Position

HIP

Y Location

(m)

(This data is

0.000 due to

new software

used this year)

Set Position

SHOULDER X

Location

(m)

(This data is
0.000 due to
new software
used this year)
Set Position

SHOULDER Y

Location

(m)
(This data is
0.000 due to
new software
used this year)
Set Position

TOE

X Location

(m)

(This data is
0.000 due to
new software
used this year)

Hip JOINT

Peak

EXTENSION

Angular

Velocity During

Block Phase

(Deg/s)

Knee JOINT

Peak
EXTENSION
Angular
Velocity During
Block Phase
(Deg/s)
YES YES

0 0 0 0 0 418.27 415.99

0 0 0 0 0 173.2 325.7

0 0 0 0 0

0 0 0 0 0 311.4 382.3

0 0 0 0 0 327.7 540.8

0 0 0 0 0 307.6 416.2

0 0 0 0 0 101.2 91.0

0 0 0 0 0

0 0 0 0 0 143.5

0 0 0 0 0 140.0 138.0

0 0 0 0 0 94.0 142.6

0 0 0 0 0 155.0 165.0

0 0 0 0 0 133.1 148.5

0.00 0.00 0.00 0.00 0.00 26.87 14.44

Sprint Start Kinematic Data – Table 3

Block Phase / Block Clearance FROM Digitised Data Block Phase / Block Clearance

Block

Clearance

Rear Hip

JOINT Angle

(Deg)

Data not

needed, as

should have

been angle at

REAR FOOT

clearance not

BLOCK

clearance!

Block

Clearance

HIP

Y Location

(m)
Trial
Number Subject Name
Block
Clearance
HIP

X Location

(m)

HIP

Y Velocity at

Block

Clearance

(m/s)

HIP

X Velocity at

Block

Clearance

(m/s)
YES YES YES

0.09 Subject1 0.94 0.54 3.65

0.11 Subject2 0.87 0.11 3.21

0.01 Subject3 0.36

0.02 Subject4 1.21 -0.13 3.26

Subject5 1.34 0.24 3.23

0.06 MEAN 1.09 0.22 3.34

0.05 Standard Devn. 0.22 0.25 0.21

0.05 Subject6 1.01 0.1 1.98

0.18 Subject7 0.82 -0.21 2.33

Subject8

0.02 Subject9 1.03 -0.23 3.10

Subject10 2.17 2.15

0.08 MEAN 0.95 0.46 2.39

#DIV/0! 0.09 #DIV/0! #DIV/0! 0.12 1.15 0.49

First Stance

Shoulder at 2.000 metres FROM START LINE

First Stance

Touchdown

HIP
X Location
(m)
First Stance
Touchdown

TOE

X Location
(m)
First Stance

Take-Off

HIP

X Location
(m)
First Stance

Touchdown

ANKLE Joint

Angle

(Deg)

Minimum

ANKLE Joint

Angle During

First Stance
Phase
(Deg)

Shoulder at 2.000

metres FROM

START LINE

(Need to subtract or

add X distance of

shoulder from

START LINE in set

position, to identify

CORRECT Frame

No.)

Frame No.

HIP

X Velocity

at 2.000 metres

FROM START

LINE

(m/s)
YES YES YES

1.21 1.49 1.8 105.9 78.7 169 4.52

0.9 1.43 1.65 123.8 116.7 174 4.89

1.09 1.52 1.80 144.1 115.7 859 4.87

1.25 2.05 2.30 154.2 96.3 286 4.82

1.43 2.15 2.28 128.5 118.5 349 4.78

1.18 1.73 1.97 131.3 105.2 367 4.78

0.20 0.34 0.30 18.7 17.3 285 0.15

1.13 1.66 1.89 119.3 107.0 223 4.36

0.38 1.51 1.54 113.2 112.3 278 3.43

147.2 97.8 380 3.70

1.09 1.71 1.81 111.5 103.0 494 4.74

101.5 95.5 478

0.87 1.63 1.75 118.5 103.1 371 4.06

0.42 0.10 0.18 17.27 6.85 119.59 0.60

Shoulder at 2.000 metres FROM START LINE

Time from GO to

Shoulder at 2.000
metres FROM

START LINE

(s)
YES

0.92

0.97
0.98

0.99

1.02
0.98

0.04

1.02
1.10

1.13

1.17

1.22

1.13
0.08

Bio

echa

abo

atory

uidance Instructions for Students

Sport and Exercise Science

Biomechanics Laboratory Report

Manuscript Guidance

Contents
1. Scope 3
2. Main sections of a

ab report 3
TITLE 3
ABSTRACT 3

I

N

TRODUCTION

METHOD

Participants

5
Experimental Procedure 5

Data and statistical analysis

RESULTS

DISCUSSION

7
CONCLUSION 8
REFERENCES 9
3. Manuscript 9

Format

in

g

Effective communication

Tables and figures

Symbols, units and abbreviations

References

13
4. Useful lin

hen submitting a paper to a

ournal, a scientist has to format their

ord document following the “Instructions for authors” accessible on the

ournal website. Follow this link to see an example with the Journal of Sports Science:

http://www.tandf.co.uk/journals/journal.asp?issn=0264-0414&linktype=44

You will find in this document below the instructions to follow for the submission of your lab report.

Scope

Scientists write lab reports to document their findings and communicate their significance from an experiment conducted in the lab. At degree level, we would expect you to do more than just reporting some data collected in the lab and describing your findings. We want you to demonstrate a good understanding of the research process (test of a hypothesis through appropriate inferential statistical test), and the key biomechanical concepts you are investigating.

Main sections of a lab report

TITLE

The title should be short and informative, straightforward and less than 20 words. It should summarise the main idea or finding of the manuscript simply and should identify the variables or theoretical issues under investigation, and the relationship between them. In sport and exercise science, the title will usually indicate the population being investigated (e.g. in children or male and female cyclists).

ABSTRACT (not required for the biomechanics lab report)

The Abstract summarizes four essential aspects of the report:

1. Rationale and aim to study should be clear, concise and appropriate;

2. Research design with a concise description of subjects, study design (i.e. relationships; differences), methods and main analyses;

3. Main data and key findings (Precise and concise description of main findings and inclusion of actual data);

4. Significance and major conclusions.

The abstract often also includes a brief reference to theory or methodology. The information should clearly enable readers to decide whether they need to read your whole report. The abstract should be one paragraph of 150-200 words unless instructed otherwise.

INTRODUCTION

Use this section to introduce the topic and explain what is generally known about the study. This includes brief bac

round information and rationale for the laboratory experiment. We want you to show your own comprehension of the present experiment and not just a copy of the handout of the practical. It is recommended (

American Psychological Association., 2010

) that before writing your introduction the following are considered –

Why is this problem important?

· How does this study relate to previous work in the area? Does this report build on, or differ from earlier work?

· What are the primary and

second

ary hypotheses and objectives of this study, and what, if any, are the links to theory?

· How do the hypotheses and research design link to one another?

· What are the theoretical and practical implications of the study?

A good structure to follow for the introduction is to:

· Introduce the problem, presenting the specific problem under investigation and briefly describe the research strategy.

· Explore the importance of the problem, stating why the problem deserves new research.

· Describe relevant scholarship and related literature. Avoid making a historical account, instead focus on key and recent literature which are pertinent to the study. Develop the problem with enough breadth and depth to make it generally understood but assume the reader is knowledgeable about the basic problem. Focus should be on whether aspects of this study have been reported on previously and how the current use of the evidence differs from earlier uses.

· At the end of the introduction, include a statement of the aim of the study in one sentence. This should be written in the past tense and should provide more detail than the title.

· Where appropriate, a hypothesis can be stated: “It is hypothesised that adopting a counter-movement jump technique results in faster take-off vertical velocity than adopting a stationary squat jump technique”.

Practical points:

· This section should not exceed 550 words and should not be shorter than 350 words (all word count guidance in this article is based upon a 1,750 word limit which doesn’t include an abstract).

· Cite key references that relate directly to the study but do not provide a detailed literature review.

· Start with a broad introduction to the topic area but g

rad

ually focus in on the specific issue addressed in the study. The rationale for conducting the experiment should follow (interest in conducting the experiment). Main aim and hypothesis would be presented at the end.

METHOD

Use this section of the report to provide a precise, detailed description of what was actually performed allowing repetition from investigators external to the current project. An effective method will allow the reader to evaluate the appropriateness of your methods and the reliability and validity of your results. If methods used are particularly complex and have been published in detail elsewhere, you may refer the reader to that source, in this instance you should then give a brief synopsis of the method. Typically a method will be separated into sub sections, details of which are below.

Practical points:

· Inclusive of sub sections the method section should not exceed 600 words and should not be shorter than 300 words.

· Write the Method in the past tense. The experiment has been done!

· The Method can be divided into sub-sections. These are usually Participants, Procedure (or Experimental Design) and Analysis.

· Do not use bullet points.

Participants

· Include relevant details such as number of participants and their sex. It may be important to state eligibility and exclusion criteria, including restrictions based on demographic characteristics

· For physiological and biomechanical manuscripts include relevant descriptive variables such as age, body mass and height where appropriate. It is usual to report the mean and standard deviation and/or the range for the group or sub-groups e.g. the participants’ mean ( SD) age was 17.5 0.8 years. For experiments with variables that fall outside of these disciplines it may be a requirement to include further detail such as skill or ability level, education, ethnicity, etc. e.g. the participants were healthy Caucasian children, coronary heart disease patients or elite athletes.

If there are a lot of descriptive details, a table of participant characteristics may be a more concise method of presenting this information.

Experimental Procedure

This sub-section should provide sufficient detail for the experiment to be repeated by others.

· Include details of equipment used but incorporate these into the text rather than providing a list of apparatus e.g. kinetic data was collected using a

istler force platform and Bioware software. (In some journals details of the manufacturer are also required but this is not necessary for the purposes of laboratory reports.)

Only include diagrams of the experimental set-up if it is unusual or to add clarity to the description. It is not necessary to describe standard procedures such as video digitising step-by-step (e.g. 3-4-5 triangle set-up, scaling information, etc.), instead it is sufficient to state something like the following: Video data of the sagittal plane motion were collected using a Panasonic HC-VX980 digital video camera, which recorded at 50

. The camera was located such that the optical axis was perpendicular to the plane of movement. Data processing was completed using the Quintic analysis software.

Data and statistical analysis

· Include a description of any data or statistical analysis procedures that were used.

· Data analysis might include things such as calculating height jumped form time in the air, data smoothing techniques, etc.

· Provide details of any statistical procedures and name the statistics package used e.g. to compare differences between two groups, an independent t-test was performed using SPSS.

· This sub-section should also include an estimation of error where appropriate.

RESULTS

Use this section to present your results and to refer the reader to the data that supports the results. Note that data (actual values) and results (statistics) are not the same thing, the results section should inform the reader of summarized data and the analysis performed on those data relevant to the discussion which follows.

Whilst the results section is often short and statement of fact it is very easy to get wrong. All relevant results should be mentioned including those that defy original expectations. You should not include individual scores, unless this is directly required by your research design, raw data should also not be included. When statistics have been used to analyse data, it is important to include the obtained magnitude or value of the test statistic, this can be presented in text, in a figure or table, or both.

Finally, results do not include a discussion of the implications. For example, do not explain WHY ground reaction force increased as running speed increased (this would be in the discussion) – just state what the results showed.

· Results are the stated messages e.g. male participants had greater impact forces than female participants.

· Data are the numbers that support results e.g. tables or figures that show the impact forces.

Graphics need to be clear, easily read, and well labeled (e.g. Figure 1: Vertical Component of Ground Reaction Force). An important strategy for making your results effective is to draw the reader’s attention to them with a sentence or two, so the reader has a focus when reading the graph (see section on Figures and Tables). Raw data (i.e. values for each subject) could be presented but usually statistical summaries are more appropriate, except where the number of participants is really small (n≤3).

Practical points:

· This section should not exceed 350 words.

· Present the results in the text, in order of decreasing importance or chronologically, whichever is most appropriate.

· You might want to think about the best way to present your data: text, tables and figures.

· But only present the data that is relevant to the research question.

· Avoid repetition of data in figures, tables and text.

DISCUSSION

Relate what you presented in the Results section to a basic physiological/biomechanical/psychological mechanism or theory and discuss the implications of the findings in relation to other literature. In other words, interpret the results and offer an explanation and application for the results emphasizing any theoretical or practical consequences. This section is the most important part of an assessed report, because here, you show that you understand the experiment beyond the simple level of completing it.

Explain. Analyze. Interpret.

This part of the lab focuses on a question of understanding “What is the significance or meaning of the results?”

Open with a clear statement of the support, or non support of your hypotheses. Similarities and differences between your work, and that of others should be used to give context to, confirm, and clarify your conclusions of the data. Each new statement should contribute to the interpretation of data, rather than being reformulation and repetition.

If an intervention was involved, discuss whether it was successful and the mechanism by which it was intended to work, and/or alternative mechanisms. Acknowledgement of any barriers to implementing the intervention or manipulation and limitations of the research should be considered as a means for clarifying the external validity of the findings. It may be that the intervention is more or less applicable to a specific population or circumstance, this should be stated.

The discussion should finish with a reasoned and justifiable commentary on the importance of your findings (this may be written as a separate conclusion: see below).

Practical points:

· This section should not exceed 650 words and should not be shorter than 450 words.

· Start by restating your research question or aim and provide the reader with the answer that was reached from the results.

· Explain the results and why these might have occurred. If a result is not as expected try and explain what might have caused this.

· Compare the results to those of previous studies.

· Include any relevant theory and reference any relevant literature.

· Discuss the limitations of the study and any possible sources of error and how they may be overcome.

CONCLUSION (the biomechanics lab report does not require a separte conclusion section. The final sentence or two of the discussion can conclude the report)

A conclusion can be very short (one to three sentences). Simply state what you know now for sure, as a result of the lab. This concluding section may be brief, or more extended, it should always be tightly reasoned, self contained and not overstated. The conclusion might briefly return to the discussion of why the problem is important, how might the findings contribute to current knowledge of the area and what propositions are confirmed or disconfirmed by the extrapolation of the findings. Often it is appropriate to state what future work needs to be done to extend your conclusions, or the implications of your conclusion. Keep it very straightforward.

Practical points:

· Summarize the findings of the study briefly but do not discuss or explain them!

· If the aim was stated in the form of a question then the conclusion should be the answer to that question.

· Restrict the conclusion to that which has been found in this study only.

REFERENCES

This is the last section of the report. Only include the source materials that were referred to in the main report. If a reference is cited in the text, it must be in the list of references. Conversely, if the reference is listed in the list of references, it must appear somewhere in the body of the text. Although you might use a number of sources of information (e.g., websites, books, etc.), only reference primarily journal articles in the report.

Manuscript

Formating

The manuscript must be double-spaced throughout, with a 3 cm margin on the left side, and a 2 cm margin on the right side with no ‘headers and footers’ (other than page numbers), and without footnotes unless these are absolutely necessary. Arrange the manuscript under headings (such as Introduction, Methods, Results, Discussion, Conclusion) and then subheadings where appropriate. The main body of the text should not exceed the stated word count, excluding references. Use a normal, plain font (e.g., 11-point Times Roman, Book Antiqua, Palatino Linotype) for the text.

Effective communication

From the instructions for authors of the Journal of Sports Science: “[Lab reports] should be written and arranged in a style that is succinct and easy to follow. An informative title, a concise abstract and a well written introduction will help to achieve this. The Journal would prefer authors to describe human volunteers as participants rather than subjects in the methods section. Figures and tables should be used to add to the clarity of the paper, not to pad it out. At all times, please try to think about your readers.”

The conventions regarding the use of the first person (I, we…), the third person (he, she, they…) and the passive voice (six participants were tested) vary in different journals. In recent years there has been a move away from an impersonal style to a more personal style. However, students often over-use the first person (“we did this then we did that”) and this detracts from a good scientific writing style. So, at the undergraduate stage of your course the advice is to write in the third person and passive voice e.g. the subject’s heart rate was measured. Avoid using third person personal pronouns (he, she, they…), unless absolutely necessary.

Practical points:

· Aim for economy of words:

· “a relationship exists” instead of “it is clear from the graphs that a relationship exists”;

· “Four participants completed the test” instead of “there were four subjects who completed the test”.

· Use words according to their precise meaning as understood by the average person.

· Use straightforward and logical phrases. Short sentences are easier to understand than long sentences.

· Think about the reader! Assume that they have some knowledge about the area but explain the main terms and theories relating to the subject area.

· Use a UK-English spell check.

· Use the past tense to describe the method and to report results (yours or others). Use the present tense to discuss them. e.g. a simple explanation is…

Tables and figures

Tables, referred to as ‘Table 1’, ‘Table 2’, and so on, must be numbered in the order in which they occur in the text. Graphs, photographs, and line drawings, referred to as ‘Figure 1’, ‘Figure 2’, and so on, must be numbered in the order in which they occur in the text. Place the title above tables and below figures. Remember tables and figures are separate entities; therefore it is acceptable to have ‘Table 1’ followed by ‘Figure 1’.

Practical points:

· Place each figure or table immediately after the paragraph that first refers to it.

· Label tables and figures with a number and title in the appropriate place e.g.

· Table titles above. E.g. Table 1: Pre- and post-training values for static and dynamic visual acuity (mean + s).

· Figure titles below. E.g. Figure 1: Mean heart rate response during a soccer game for an elite and novice striker.

· Use Figure 1 rather than Graph 1.

· The title should be meaningful in its own right, without needing to refer to the text.

· Do not include units in a title but do include them within a table or figure.

· Avoid starting your title with ‘A graph to show’ or ‘A table to show’.

The axes of your figures should be labeled with the measure (words or symbol e.g. Heart rate or HR) and followed by the units in brackets. The correct layout for a line graph, including title, is illustrated in Figure 1.

Figure 1. Distance – time relationships in 1920, 1964 and 2004.

Follow these rules for choice of figure format:

· Line diagrams or scatter grams if independent and dependent variables are numeric

· Line graphs show relationships between one variable and the next e.g. continuous data.

· Bar graphs if only the dependent variable is numeric or if the independent variable has discrete categories

· A bar graph or pie charts for proportions

· Break figures near the origin if they do not go through “0”

· Show scatter grams only for a good reason (e.g. to illustrate outliers, a nonlinear trend or a nonzero intercept); otherwise state the correlation co-efficient and/or standard error of the estimate.

· Show curves only if modeling a curve to the data.

· Think carefully about whether to join points with a line (straight not curved) or not. If doing so, be sure to recognize the limitations of the assumptions being made. See full explanation below.

There are mixed opinions regarding whether the points on a line graph should be joined with line segments. Doing so infers that there has been a linear change between data collection points. This is speculation and therefore many scientists argue against this. However, there are different practices between the disciplines. Physiologists tend to be less rigorous about this. In general, physiologists tend to have less data points than say biomechanists e.g. one expired air sample per exercise stage. When these are plotted on a line graph it may be difficult to see the relationship between points. If the relationship is expected to be linear e.g. linear increase in heart rate with increasing exercise intensity, then a best-fit line could be fitted. In other cases the points may be joined to help identify the trend. For example to identify the lactate threshold, it is necessary to join the points with lines (or fit a cubic spline, which is too complex at this level). However, it is important to recognize that these lines do not represent the change in the variable between the points.

Symbols, units and abbreviations

For a comprehensive guide to symbols, units and abbreviations, please consult the following text:

http://www.bipm.org/utils/common/pdf/si_brochure_8_en

. The Système International d’

Unit

és (SI units) and the correct abbreviations should be used. Example of SI units and abbreviations commonly used in sport science are given in Table 1.

Table 1: SI units, abbreviations and common errors

Unit	Abbreviation	Common errors
kilo gram(s)	kg	Kg, KG
gram(s)	g	G
metre	m	m., M
litre	L	l
joules	J	j
kilojoules	kJ	Kj, KJ
degree Celsius	°C	o C, oC
kelvin	K	k
second	s	secs
watt	W	w
newton	N	n
hertz	Hz	HZ
radian	rad	r

Avoid excessive use of abbreviations. Abbreviations should only be used when the full expression is excessively long or it is well known to researchers in the discipline (e.g. VO2max). Any abbreviations should be defined in brackets the first time they are used e.g. body mass index (BMI). Subsequent acknowledgements in text are then in abbreviated format

References

The Harvard system should be used. The document “School of Sport and Service Management Referencing Guidelines” is located in the my school: Sport and Service Management > Student Handbooks and Other University Docs folder on studentcentral.

More tips

· Do not abbreviate, e.g., lab = laboratory.

· Do not use contractions, i.e., don’t = do not.

· Plurals – e.g., “participant’s results” refers to an individual participant whereas “participants’ results” refers to a group of participants. In addition, “datum” is the singular of “data”, therefore, “data was” should be “data were”.

· Use of quotations – unless the definition is important (e.g., a particular referenced definition of fatigue) it is better to paraphrase.

· Avoid one-sentence paragraphs.

· Avoid use of the word “done”. Other words are more appropriate, such as “completed” or “performed”.

· Avoid use of the word “found”. Other words are more appropriate, such as “ascertained”, “calculated”, “confirmed”, “demonstrated”, “discovered”, “established”, “observed”, “reported”, showed”, etc. Each of these has a slightly different meaning so make sure it is appropriate for the context in which it is used.

· Be precise in your use of words. For example, “validity”, “accuracy”, “reliability” and “precision” have very definite meanings and should only be used in specific situations.

When spelling numbers?

· Numbers beginning a sentence must be spelled: Twelve participants instead of 12 participants.

· Rewrite a sentence to avoid starting it with numbers greater than ninety-nine.

· When quoting numbers, use words for numbers one to nine and numbers for 10 onwards. Exceptions: a 2 m tape measure, 3 million people.

Format

· Unless necessary, use tilde (~) to mean approximately equal to. But in science, it should never be “~10 mL.min-1.kg-1” but rather “=10.1 ± 2.8 mL.min-1,kg-1”

· Use the following format for presenting numbers:

0.64 not .64,

125

2,461 or 2461

21,278

1,409,000

· Put a space between numbers and units e.g. 92 kg. Exceptions: 55%, 21°C.

· Use the style superscripted style – ml.kg-1.min-1 for scientific writing purposes. (The style ml/kg/min can be used for non-scientists).

· Use the minimum number of significant digits or decimal places. For example, 19 ± 2 years is easier to read than 19.4 ± 1.8 years, and the loss of accuracy is not important in this situation.

· Use the appropriate number of digits:

· Think about the precision in your measure and then chose the number of digit.

· 125.3 ± 10.2 cm – did you measure each height with 0.1 cm accuracy? No, so you should write 125 ± 10 cm

· 4444 mL.min-1; 333 cm; 22.2 mL.min-1.kg-1, 1.11 mmol.L-1

· Two decimal places for correlations (r = 0.76). Two significant digits for percentages (3.5%, 12%)

Useful links

http://www.writing.utoronto.ca/advice/specific-types-of-writing/lab-report

http://www.studygs.net/labreports.htm

http://www.mhhe.com/biosci/genbio/maderinquiry/writing.html

AMERICAN PSYCHOLOGICAL ASSOCIATION. 2010. Publication manual of the American Psychological Association, Washington, DC, American Psychological Association.

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Biomechanics-sprint start kinematics repor

I N TRODUCTION

METHOD

Participants

Data and statistical analysis

RESULTS

DISCUSSION

Format in g

Effective communication

Tables and figures

Symbols, units and abbreviations

References

Scope

Main sections of a lab report

TITLE

ABSTRACT (not required for the biomechanics lab report)

Manuscript

Useful links

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TRODUCTION

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