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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Proposing of Planning System for Sports Domain: A Tool for Professional Coaches Tom a´sˇ Sˇkerˇ´ık, Wolfgang Faber, Luka´ sˇ Chrpa</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Tom a´sˇ Sˇkerˇ´ık</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Wolfgang Faber</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Luka´ sˇ Chrpa</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>School of Computing and Engineering The University of Huddersfield</institution>
          ,
          <addr-line>Queensgate Huddersfield, HD1 3DH</addr-line>
        </aff>
      </contrib-group>
      <abstract>
        <p>This paper introduces the System for Sports Training Planning (SSTP), which aims to be used as an automated planning application that generates training plans for individual athletes. This paper mainly presents the sports domain, the system's high-level architecture, ongoing development, and its challenges.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>
        Recently, athletes performance developed beyond all
expectation and prediction. Old records, which were considered
as unbreakable, are reached even by amateurs during their
training units. These have been enabled especially through
better nutrition and improved training methods
        <xref ref-type="bibr" rid="ref2">(Bulchandani 2012)</xref>
        . In all sports, the key to reach high level
performance lies in the athletes preparation in trainings. There
cannot be a success without proper training planning and
corresponding training execution on the highest level
        <xref ref-type="bibr" rid="ref12">(Mez˙yk
and Unold 2011)</xref>
        . Nevertheless, training planning is a
wellknown problem in the sports domain and only top level
coaches are able to deliver training plans of sufficient
quality to enable athletes to perform on their very best. Training
planning is a complex process, which is affected by a
multitude of factors that also vary according to different sports.
These factors include variables such as athletes
predispositions, athletes health conditions, competition goals, weather
conditions, and others
        <xref ref-type="bibr" rid="ref16">(Smith 2003)</xref>
        . The vast amount of
variables makes planning a process, which depends on
basic principles that are provided in the coaching literature.
      </p>
      <p>The purpose of this research is a development of an
automated planning system that uses a specific sports knowledge
base and desired goals as an input for a planner that will
create individual training plans for athletes. This will provide
efficient solutions for coaches from various sports to create
plans without having a vast background knowledge or the
need of being an expert in automated planning. In order to
reduce the complexity of having very varied requirements
in diverse sports, one specific sports domain, namely
kickboxing, has been chosen as a case study. The chosen domain
will serve as a stepping stone and proof of concept for
further development.</p>
    </sec>
    <sec id="sec-2">
      <title>Sports Domain</title>
      <p>
        In the 21st century, computing and network technologies are
daily life necessities and also play more and more
significant roles in sports training. The most significant progress
has been made in the usage of computing in scientific sports
training, which leads to a systematic approach of
training, performance measurement, and competition analysis.
This contributed to training efficiency improvement, athletes
performance and it also helped to prevent some sports
injuries
        <xref ref-type="bibr" rid="ref8">(Hou 2015)</xref>
        . Computing technologies involved in the
sports domain usually are data acquisition and data
processing, databases, modelling and simulation, which are
used in training and coaching, biomechanics, sports
equipment, and computer applications. In addition, usage of AI
is no exception either. Most of the research concerning AI
in sports domains is focused on the prediction of sports
outcomes, game-time analysis to enable efficient decisions
during competitions, sports biomechanics for performance
analysis, which is facilitated by expert systems and neural
networks to gait analysis
        <xref ref-type="bibr" rid="ref10">(Lapham and Bartlett 1995)</xref>
        .
Another commonly used AI technique is pattern recognition,
which is for example used in football game analysis and
weight training
        <xref ref-type="bibr" rid="ref14">(Novatchkov and Baca 2013)</xref>
        .
      </p>
      <p>However, no literature on sports training planning seems
to be available. As a result, the intention of this article is
to outline an ongoing project that deals with utilising
automated planning in sports domains. For that reason there is a
need to identify what is meant by a sports domain and what
elements will be used as an input for automated planning.</p>
      <p>At first, there is a need to address what sports explicitly
means. Collinsdictionary.com (2016) defines sport as:
an individual or group activity pursued for exercise or
pleasure, often involving the testing of physical
capabilities and taking the form of a competitive game such
as football, tennis, etc.</p>
      <p>The term sport has many definitions, but all of them
suggest that sports are primarily concerned with reaching the
best possible performance in a particular discipline.
Essentially, athletes in order to achieve required outcomes and
performance during competitions, have a need to adequately
train before the competition takes place. Athletes are
typically guided by coaches, who provide them with knowledge
in the specific sports domain. This knowledge is usually
transferred by means of training units, which are planned
according to coach experiences. In other words, the main
objective of sports training is to reach the very best
performance in the planned competition.</p>
      <p>Sports training can be defined as a set of training
methods and exercises, which are executed by an athlete in order
to prepare for a competition. To be able to utilize the best
from training, it is necessary to carry out the methods and
exercises in precise manners. For that purpose a tool called
annual training planning has been developed. Nevertheless,
this tool requires vast knowledge and time resources.</p>
      <sec id="sec-2-1">
        <title>Annual Training Planning (ATP)</title>
        <p>
          <xref ref-type="bibr" rid="ref9">Kassa (2011)</xref>
          describes the annual training plan as a tool
used by coaches, which serves as a base for all scheduled
training activities over a year. The annual training plan is
an important tool for enhancing an athletes performance.
An ATP is constructed on the concept of periodisation,
which divides an athlete’s year into manageable training
periods
          <xref ref-type="bibr" rid="ref13">(Milanovic´ and Sˇ alaj 2014)</xref>
          . These periods are focused
on development of different abilities such as strength,
endurance, and speed
          <xref ref-type="bibr" rid="ref1">(Bompa 2009)</xref>
          . Furthermore,
periodisation is a process, which allows to formulate sports program
in systematic fashion.
        </p>
        <p>Forming an ATP has following steps (Olander, 2015):</p>
        <sec id="sec-2-1-1">
          <title>Information gathering</title>
        </sec>
        <sec id="sec-2-1-2">
          <title>Analysing the last programme</title>
        </sec>
        <sec id="sec-2-1-3">
          <title>Assessing athletes performance</title>
        </sec>
        <sec id="sec-2-1-4">
          <title>Input the peak events of a year</title>
        </sec>
        <sec id="sec-2-1-5">
          <title>Dividing year according to periodization</title>
        </sec>
        <sec id="sec-2-1-6">
          <title>Outlining objectives of each phase</title>
        </sec>
        <sec id="sec-2-1-7">
          <title>Determining activities of each phase</title>
          <p>Identifying of volume intensity and recovery relationship
within a season
Determine a total number of training hours to be
complete.</p>
        </sec>
        <sec id="sec-2-1-8">
          <title>Identify appropriate training units for each phase</title>
          <p>To perform all these steps, it is necessary to have a high
level of knowledge in the field of sports science. Also, it
is essential to have a great understanding of athletes, who
are being trained, be aware of all possibilities and
circumstances, which can occur during the season and most of all
possess a great deal of planning abilities. In order to have
accurate and precise input for an ATP and objective
outcomes, there is a need to understand athletes’ performance
and methods by which it can be measured.</p>
        </sec>
      </sec>
      <sec id="sec-2-2">
        <title>Performance Evaluation</title>
        <p>
          One of the best known definitions of sports performance was
defined by
          <xref ref-type="bibr" rid="ref6">Hay and Reid (1988)</xref>
          : performance as the
manner in which all movements comprising motor skills – a
series of voluntary movements of the human body designed to
achieve a specific goal - are executed. In other words,
performance is a goal-directed set of movements, and the process
of evaluating and analysing an individual athlete’s
execution of a specific task and a level of skill involved in the
task. That said, there is a need to evaluate performance in
all sports as it is used for determining competition winners
and also for sports training improvement. One of the main
purpose of performance evaluation (PE) is to obtain sports
specific data, which are analysed in order to detect errors in
training process and adopt corrective actions
          <xref ref-type="bibr" rid="ref15">(Owusu 2007)</xref>
          .
        </p>
        <p>
          <xref ref-type="bibr" rid="ref7">Higgins (1977)</xref>
          views PE as a complex process that
includes numerous stages, which are:
        </p>
        <sec id="sec-2-2-1">
          <title>Describing what should happen</title>
        </sec>
        <sec id="sec-2-2-2">
          <title>Describing what happened</title>
        </sec>
        <sec id="sec-2-2-3">
          <title>Comparing expectations with results</title>
        </sec>
        <sec id="sec-2-2-4">
          <title>Taking corrective actions Contribution to the view of Higgins’ PE have been done by Fairs (1987), who described five steps in performance evaluation:</title>
        </sec>
        <sec id="sec-2-2-5">
          <title>Data collection</title>
        </sec>
        <sec id="sec-2-2-6">
          <title>Diagnostics</title>
        </sec>
        <sec id="sec-2-2-7">
          <title>Prescribed plan of action</title>
        </sec>
        <sec id="sec-2-2-8">
          <title>Implementation</title>
        </sec>
        <sec id="sec-2-2-9">
          <title>Evaluation</title>
          <p>The process of PE typically includes collection and
analysis of large amount of biased information about athlete’s
performance. According to Fair’s data collection is fact-finding
part of PE process, where data are drawn without making
any conclusion or interpretation. He claims that the data
collected in this step can be of an objective and a subjective
manner. Subjective data are usually provided by an athlete,
while objective data are collected by evaluator using specific
equipment for explicit measurement.</p>
          <p>
            The PE procedure is based on several expertises and it
can differ according to various sports. Further, sports
performance can be measured in many possible ways and it usually
involves qualitative and quantitative analysis of human
motion, coaching methods and biomechanics. The qualitative
analysis of sports performance is based on a visual
observation of human motion. This analysis is usually done by
evaluators and accuracy of this method depends on their
experience and equipment they use. This method is inclinable
to errors as it relies on the evaluator getting a clear picture
of joint movements as they occur, which can be in some
situation difficult
            <xref ref-type="bibr" rid="ref4">(Fernandes, Anes, and Abrantes 1996)</xref>
            . On
the other hand, the quantitative approach retrieve an
objective data, which have a form of biochemical profile of
motion, which is being analysed
            <xref ref-type="bibr" rid="ref15">(Owusu 2007)</xref>
            . Nonetheless,
this approach is vastly time consuming. One of the reasons
is that biomechanical quantification is a manual process.
          </p>
          <p>
            In addition,
            <xref ref-type="bibr" rid="ref11">Maglischo (2003)</xref>
            describes blood testing
processes for monitoring heart rate with reference to
training managing and monitoring. Also,
            <xref ref-type="bibr" rid="ref5">Friel (2016)</xref>
            describes
proper and effective methodical approach of making training
logs, which are aimed to create better experience of training
preparing phase usage. These two papers are stepping stone
into methodological training and performance testing
methods that are used for the research.
          </p>
          <p>With a rising number of analysed athletes, the
complexity can radically increase. This can be seen in situations
when the coach has to remember information about more
than twenty athletes. This information consists of their
personal information (age, weight, height, etc.), number and
performance of athletes competitions, and their strengths
and weaknesses. Retaining and analysing of these
information brings difficulties, which usually are reflected in
training efficiency, and therefore in performance efficiency.</p>
          <p>
            It is therefore not surprising that numerous
computerbased systems have been developed in order to increase the
speed and quality of performance evaluation
            <xref ref-type="bibr" rid="ref15">(Owusu 2007)</xref>
            .
A large number of these systems are visual. The
principal idea of these systems is to capture the complete
athlete motion into digital form and then input these visual
data for quantification into computers, where these data are
analysed. Consequently, this provides enormous possibility
for AI techniques. Nevertheless, AI techniques in PE have
currently only limited capabilities. The main reason is that
sports domain lacks of characterisations in terms of
quantification of sports science. This fact is also one of the obstacles
for this research.
          </p>
          <p>For this reason, there is a need for a sports domain
specification that will provide input for a planner, which will result
in generating an annual training plan. In order to create a
sports domain model, there is a need to examine sports
performance, physical abilities, training methods, training
planning and testing of athletes, and adapt this concepts on
concepts of automated planning.</p>
        </sec>
      </sec>
      <sec id="sec-2-3">
        <title>Proposed System Architecture</title>
        <p>The proposed planning system will be developed on an
ontology core that will provide a clear formalism and
userfriendly environment for domain experts, namely coaches
and sports science researchers, to be able to encode sports
domain knowledge. The encoded knowledge and an input
required for creating initial and goal state will be transferred
into Planning Domain Description Language.</p>
        <p>The system architecture (depicted in Figure 1) is based
on two main AI concepts, which are automated planning
and ontology. A high-level architecture of the system can
be seen in figure 1. In proposed scenario ontology outlines
the sports domain itself. In other words, the system ontology
will consist of objects definitions, their relationships, and
hierarchies, action types and methods. Classes will represent
individual body elements, such as energy systems, muscular
system and technical and tactical capabilities. Action types
will consist of action name, logical preconditions and effect.
Methods will be used as an abstraction of the actions. In
other words, methods will be used as high-level tasks that
consist of actions which have an explicit ordering.</p>
        <p>The input part of the architecture is focused on generating
a planning problem that is going to be created by inputting
three main parts, the first is an athlete’s current performance,
peak events for which the athlete is aiming for, and
correction values that will be provided by analysis of the athlete’s
previous annual training plan. These three parts will be used
for generating initial state, objects, and a goal state.</p>
        <p>The next step in the process of planning is fetching the
domain and planning problem into chosen planner and
generating the annual training plan.</p>
        <p>After the plan is generated, it has to be executed for a
specific amount of time (chosen by coach). The chosen time
period has to be long enough for the athlete’s body,
therefore the athlete’s performance, to respond. When this time
frame runs out, a performance evaluation process takes a
place. Reached performance is compared with the planned
goal state. If the goal state is met, the athlete continues with
plan execution. Otherwise, the reached state becomes the
new initial state and re-planning process is initiated.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Ongoing Work</title>
      <p>The system architecture described above provides a main
concept of the research idea. Nonetheless, there is still need
to completely define the sports domain, which would
connect sports training methods, and exercises with their impact
on a human physiology and automated planning concepts.</p>
      <sec id="sec-3-1">
        <title>The Next Steps</title>
        <p>
          The first attempt to produce automated training plan will
be done through a knowledge encoding tool called KEWI.
KEWI was developed in order to provide for domain
experts, who are not experts in AI planning, a user-friendly
solution for encoding classical planning domains. This tool
can export domains into PDDL that can be used with
standard planning engines
          <xref ref-type="bibr" rid="ref13 ref17">(Wickler, Chrpa, and Leo McCluskey
2014)</xref>
          . The concept of KEWI is building on an ontology that
furnishes necessary parts of classical planning, such as
objects, their hierarchies, action types, preconditions, effects
and methods
          <xref ref-type="bibr" rid="ref13 ref17">(Wickler, Chrpa, and Leo McCluskey 2014)</xref>
          .
In order to be able to encode the knowledge into the
ontology that is specifically developed for classical planning use,
there is a need of major simplification of sports science
constructs.
        </p>
        <p>Example The athlete’s sports performance can be broken
down into four main categories, which are energy systems,
muscular system, technical and tactical skills. Each activity
(training method, or simply exercise) has a different impact
on individual abilities of the athlete. The activity impact is
only hardly measurable, which makes it almost impossible
to define activity with accurate effects. Furthermore, each
activity has to be executed for a certain amount of time and
be placed in a time frame (training unit). As the domain is
being developed under classical planning, the time
requirement has to be relaxed.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Challenges</title>
      <p>The domain has to be concrete in the sports science
findings. The fact that sports science is based on several other
sciences, such as anatomy, biomechanics, biochemistry and
bio-kinetics, makes the encoding of the domain very
challenging. The domain specification itself brings several
problems that have to be dealt with. These are for example:
1. Quantification of four different performance abilities.
2. Automation of sports training methods and exercises with
correspondence with automated planning concepts.</p>
      <sec id="sec-4-1">
        <title>3. Addressing activities duration requirement.</title>
        <p>4. Incorporate specific breaks between individual exercises.</p>
      </sec>
      <sec id="sec-4-2">
        <title>5. Identify how to prioritize actions.</title>
      </sec>
      <sec id="sec-4-3">
        <title>6. Identifying of a goal state.</title>
        <p>Currently, different types of automated planning are
being addressed, which could satisfy the system requirements.
Momentarily, the main focus is on classical planning as it
can provide a working prototype of the proposed system.
Nonetheless, the sports domain has some needs, which
classical planning cannot facilitate. For example, each action in
the sports domain requires for an execution certain amount
of time. That could be supplied by temporal planning that
is allows for expressing time explicitly. Executed actions or
planning operators do not have an immediate effect, but
incur a pre-defined delay. Temporal planning could also
provide a solution for incorporating breaks between individual
exercises as each durative action has effects with two sets.
One set represents the effects taking place during execution
and the other set represents the effects that take a place
after the execution of the action. Further, this could be used
as representation of athletes’ power supplies. After
execution of an exercise an athlete would require a refreshing of
power supplies in order to execute the next planned exercise.
This process would continue until the athlete’s power will be
completely depleted or the training session will terminate.</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Conclusion and Future Work</title>
      <p>In this paper, we have introduced an automated planning
application on a real case scenario concerning sports training
planning. In other words, this paper presents a sports training
planning system architecture and its ongoing development.
This work is carried out in order to develop a planning
system that will enhance the sports training process. It will
create training plans based on the latest sports science research
and explicit athlete performance data. This would be a
significant enhancement in sports training as currently there is
no sophisticated tool that could provide any level of training
planning automation. Subsequently, the development of the
sports domain, even though with specific orientation, could
provide a tool for a range of sports scientists that would
benefit from using this system.</p>
    </sec>
  </body>
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