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Analysis of thermal comfort
and sport performance
in cross-country skiing athletes
wearing different types of clothing
Alessandro Pezzoli
DIST, Politecnico di Torino & Università di Torino, Viale Mattioli 39, 10125 Torino, Italy
alessandro.pezzoli@polito.it
Materials for Tomorrow 2014 – Chalmers University
Goteborg 6th November 2014
THE COACHING «WHEEL»
Australian Olympic Committee
Model of 6 general dimension obtained after a
structured interview of 22 elite athletes and
coaches of Athletics (U.S.A. National Team).
Factors that define the performance in the track
race…
Athlete and coach perception of technology needs for evaluating running performance
(Fleming, Young, Dixon & Carré, 2010 – Sports Eng.)
Tree diagram for the main
dimension Environment
SPORT, ENVIRONMENT AND PERFORMANCE
Factors which can affect a
player’s football specific en–
durance capacity. The factors
which are presented in the red
boxes cannot be influenced by
either the player or the coach.
«Precision Football», Balsom P.,
Ed. Polar
SPORT, ENVIRONMENT AND PERFORMANCE
THE PERFORMANCE ANALYSIS
The Performance Analysis is an
objective way of recording
performance so that key
elements of that performance
can be quantified in a valid and
consistent manner
(Hughes & Franks, 2007)
The area of the Performance
Analysis
The final aim of a
measurement process is taking
a decision (Ferrero, 2005)
WHY IS IT IMPORTANT TO MEASURE
THE METEOROLOGICAL AND SNOW PARAMETERS
DURING TRANING, FIELD TEST AND RACE?
The «skiing conditions» in «A», «B» and «C» are comparable???
QUESTION…
THE INSTRUMENTS…
The characteristics of the Weather Instruments for the assistance at the sport
activities are:
moveable
small in size
easily and quickly to be installed
automatic and with data-logger
reliable, robust and usable even in adverse weather conditions
with the possibility to process the recorded data with a dedicated "software"
THE THERMAL COMFORT: WBGT
Cost: app. 3.000€
WBGT = 0.7 x Tnwb + 0.2 x Tg + 0.1 x Ta
The WBGT is complex to use for the Winter Sport. Better using the NET Index…
THE THERMAL COMFORT: AT & HI & NET (1)
Cost: app. 600€
THE THERMAL COMFORT: AT & HI & NET (2)
THE SURFACE TEMPERATURE (1)
Cost: app. 300€
THE SURFACE TEMPERATURE (2)
Snow: T1 measures the snow
temperature in surface until
10.30LT then the air temperature
in the boundary layer with the
snow
THE SURFACE TEMPERATURE (4)
Cost: app. 200€
THE SURFACE TEMPERATURE (5)
Cost: app. 3.000-4.000€
THE SURFACE TEMPERATURE (6)
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (1)
The main goal of this study is to clearly evaluate how materials used in winter sports, with a
particular focus on the cross-country skiing materials, perform when used in their application
fields in terms of breathability and capability to control temperature and moisture.
In this research it is presented an innovative test protocol that can match the correlation
between comfort and performance by testing three different technical underwear, from
middle to high-end quality.
The studies about the thermal comfort were carried out predominantly with test protocols in
a climatic chamber. To expand the scope of research, it would be necessary to conduct
studies in outdoor environment with the chance to analyse sports that cannot be easily
reproduced in a climatic chamber (i.e.: cross-country skiing, alpine skiing, canoeing).
An innovative on-field testing has been performed on cross-country ski athletes and
instructors; the data from the wireless sensors measuring skin temperature and humidity
have been validated by using a portable meteorological station. A questionnaire has been
proposed to testers, trying to describe the feelings in function of the different clothes worn.
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (2)
Garment A
Garment B
Garment C
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (3)
Garment A: Highly functional sport underwear with good thermal insulation.
Usable for all winter activities. The garment is made with “woven technology” so
in frame weaving two systems of threads arranged perpendicularly to one
another. By weaving different weaves, it creates of the surfaces with different
characteristics. With the addition of “elastan” it is also get extra stretchy fabrics.
Garment B: polyester fabric with a high percentage of elastane, highly insulating
structure, not only protects from the outside elements acting on the body
temperature, but reduces the body heat. The maintenance of body temperature
comes directly from the body through a product that guarantees a greater ability
to retain heat, giving high protection and comfort, especially in remote areas
such as the neck. The internal structure captures the moisture to transfer it to
the upper layer.
Garment C: revolutionary garment, recently introduced on the market,
composed of two layers: a net in contact with the skin with the purpose of
trapping the moisture and transfer it externally and a second layer in polyester
for an adequate thermal comfort in cold climatic conditions.
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (4)
For four days in a week, instructors have used garments and exchanged them,
without knowing what clothing they were wearing, to make the following
comparison:
•Day 1: Base layer A(1st instructor) – Base layer C(2nd instructor)
•Day 2: Base layer C(1st instructor) – Base layer A(2nd instructor)
•Day 3: Base layer B(1st instructor) – Base layer C(2nd instructor)
•Day 4: Base layer C(1st instructor) – Base layer B(2nd instructor)
Of course, since it was a test protocol in outdoor conditions and not in a climatic
chamber, also data of the weather and snow were recorded day by day with a
special device.
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (5)
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (6)
As for the analysis of the environmental conditions, we found out a parameter that
could indicate if the tests had been carried out under the same conditions. To do
this, it was decided to refer to apparent temperature index
Among these, the most suitable to be used was the Net Effective Temperature Index
alias NET,which reflects the perception by the population to feel more "stress" on
cold, windy and wet winter days or hot, humid summer days without wind. It is
obvious that low values of NET in winter and high values of NET in summertime are
index of more "stressful" weather. The NET index can be used indifferently, both in
winter (with low air temperatures) and summer (with high air temperature); on the
contrary to the most known Windchill Temperature Index (WCT), NET is not only a
function of air temperature and wind speed but also of air humidity.
NET 37
..
...
0.29T 1 0.01RH
where T is the ambient temperature (°C), v the wind speed (ms-1) and RH the
relative humidity (%).
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (7)
For our tests we used four iButtons for each tester, applied directly to their skin
through a special support and a strip of tape. The objective of the device was to
record the values of temperature and humidity on the chest area and on the lumbar
area every sixty seconds; this provided a detailed mapping of the parameters
measured during the testers’ performance
Cost : app. 100 ÷ 120€...
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (8)
We adopted a protocol based on a method of mixed
parallel research, so we have prepared a
questionnaire to better understand the feelings
experienced by the tester according to the apparel
worn. Using this extremely innovative method in the
research of sport engineering applied to the study
of sport equipment, both qualitative and
quantitative approaches have been used, in a way
that the results of a part doesn’t influence the
methods of the other one.
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (9)
Test 24th February 2012 and 26th February 2012
(Tester 1)
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (10)
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (11)
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (12)
Comfort’s sensation function of TS (Mean Skin Temperature in °C)
and ASW (Mean Skin Relative Humidity in %)
RESEARCH: THE THERMAL COMFORT AND THE CLOTHING (13)
CONCLUSION AND SUMMARY TABLE
•Garment A: It has good moisture management and keeps the skin dry and warm. It's a high-
tech sport underwear and fit soft, comfortable and tight. Integrated ventilation zones for
optimal moisture transport and material with high breathability.
•Garment B: The maintenance of body temperature comes directly from the body through a
product that guarantees a greater ability to retain heat, giving high protection and comfort,
especially in remote areas such as the neck. The internal structure captures the moisture to
transfer it to the upper layer. This particular type of construction has, however, the defect to
create an increased skin temperature in association to high humidity values, especially in
people with high sweating.
•Garment C: The clothing has worked very well with all the testers, showing similar results. The
comments gathered from the questionnaires, confirmed by quantitative measures, have been
particularly focused on its fit, especially in the lumbar region. The shirt, which was not very
adherent on the back, has shown a little decreasing in its effectiveness. This fabric, composed of
two layers, must be very tight to perform a positive pumping effect with a high evaporative
power. It was very interesting the tester’s suspicion that this garment was thicker than the A
and B. At the end of the tests, supported by quantitative values of skin temperature and
humidity, the testers were able to admit the functionality of this underwear.
CONCLUSION (1)
The performed analysis clearly shows that both meteorological and environmental
parameters can have a significant impact on the sports performance for outdoor events.
We can conlude that, in the sports performance analysis, need to be addressed, as well as
the well-known areas of Performance Analysis, which are :
•Motion Analysis
•Match & Timing Analysis
•Notational Analysis
also two new areas, namely:
•Rule Analysis
•Environmental Analysis
CONCLUSION (2)
Meteorology applied to the Sport Research Unit
Bio-Meteorology
Research Area
Applied Meteorology
Research Area
Materials & Environment
Research Area
Sports & Environment
Research Area
Technology & Environment
Research Area
MeteoSport: A UNIQUE UNIVERSITY RESEARCH UNIT IN
METEOROLOGY APPLIED TO THE SPORTS
Analysis of thermal comfort
and sport performance
in cross-country skiing athletes
wearing different types of clothing
Alessandro Pezzoli
DIST, Politecnico di Torino & Università di Torino, Viale Mattioli 39, 10125 Torino, Italy
alessandro.pezzoli@polito.it
Materials for Tomorrow 2014 – Chalmers University
Goteborg 6th November 2014