The research described in this thesis used a standardised battery of tests called the
‘Rugby League Athlete Profiling (RLAP)’ battery for assessing the anthropometric and
physical characteristics of UK-based rugby league players. The overall purpose of this
research was to determine the utility of the RLAP battery, which involved establishing
the use of RLAP across numerous professional clubs over a three-year period,
determining the measurement properties of the tests included and investigating the
factors associated with a change in the characteristics.
An early version of the RLAP battery existed [called SPARQ] and was provided by the
Rugby Football League with scope to alter this as part of this programme of research.
Before determining if an alteration to the battery was required, it was essential to
understand the tests that are currently used in rugby league for assessing the
anthropometric and physical characteristics of players. As such, the systematic review
initially sought to determine the volume of performance tests used in rugby league
along with their measurement properties. Based on the results, it was evident that a
shorter sprint distance (< 20 m) ought to be included in the battery. It was also clear
that only one field-based method for measuring muscle strength was available, though
had received minimal research. Furthermore, the review highlighted that no rugbyspecific intermittent running test had previously been used and that RLAP was the first
battery to include such a test. Therefore, based on these results, the battery was
rebranded to RLAP, which included a stature, body mass, a 10 m and 20 m sprint test,
a rugby-specific intermittent test, a change of direction test, measures of lower- and
whole-body power.
With the RLAP battery confirmed, it was then used and the reliability (Chapter 4) and
discriminant validity (Chapter 5) of its elements determined. Results indicated that the
RLAP battery is reliable and does not require habituation. Furthermore, the calculation
of the required change, which includes the worthwhile change and random error of
each test, provides researchers and practitioners with a single value that can be used
as an analytical goal to evaluate a true change in characteristics with confidence. All
components of the RLAP battery (except 10 m sprint time) possessed adequate
discriminant validity between youth, academy and senior rugby league players,
suggesting this battery can accurately distinguish between playing standards.
As noted in above, the review highlighted a rugby-specific intermittent test has yet to
be established in the literature before its inclusion in the RLAP battery. Whilst it
appeared to be suitable and, based on Chapters 3 and 4, is reliable and possesses
discriminant validity, the test itself had received no previous attention. Given the
novelty of this test, it was unknown if this test was better associated with the responses
to rugby league match performance and what the physiological responses were to this
test. As such, Chapter 5 sought to determine the concurrent validity of this test and
compare it against the traditional Yo-Yo Intermittent Recovery test level 1 (Yo-Yo IR1).
The results indicated the association between prone Yo-Yo IR1 distance and the
external, internal and perceptual responses to simulated match-play was improved
when compared to the Yo-Yo IR1. Chapter 6 demonstrated that starting each 40 m
shuttle in a prone position increases the internal, external and perceptual loads whilst
reducing the total distance achieved. The degree of shared covariance between the
prone Yo-Yo IR1 and Yo-Yo IR1 suggest the rugby-specific test provided insight into
additional characteristics associated with rugby league performance.
In studies that have reported on the anthropometric and physical characteristics, few
have considered the multiple factors that might influence these with no studies
conducted in rugby league. Chapter 7 sought to determine the complex interaction
between anthropometric and physical characteristics that requires careful
consideration by those involved in developing youth and academy athletes. The
results also revealed a number of contextual factors such as season phase, league
ranking, playing age and playing position that can influenced the change in
characteristics over the course of a competitive season. The findings of this study
highlight how some characteristics are impaired towards the end of the season, thus
providing a rationale for considering in-season training loads and the application of
short training interventions to off-set these negative changes.
Based on negative changes in some anthropometric and physical characteristics
towards the end of the year, Chapter 8 reported on the efficacy of two in-season sprint
interval interventions for enhancing the physical characteristics of rugby league
players. Furthermore, the study provided insight into the sensitivity of the RLAP battery
for detecting changes in the characteristics of rugby league players. The results
highlighted that two weeks of rugby-specific and running-based sprint interval training
appeared affective for promoting the physical characteristics of rugby league players
with minimal deleterious effects on wellness and neuromuscular function. Using the
reliability statistics from Chapter 1, the mean change for prone Yo-Yo IR1 in the rugbyspecific group met the required change whilst changes approached this value for the
running-based group despite contrasting loads. In all, this study demonstrated that
sprint interval training that includes sport-specific actions is a suitable and effective
training modality that can be used in-season. In addition, the result demonstrated how
the prone Yo-Yo IR1 was sensitive to change across the intervention period whilst
others were not sensitive to sprint interval training due to the lack of specificity.
This thesis provides a thorough evaluation of the RLAP battery that can be used by
researcher and practitioners to assess the anthropometric and physical characteristics
of rugby league players. The battery is reliable and possess discriminant validity, while
the prone Yo-Yo IR1 has concurrent validity and is sensitive to change during a lowvolume in-season training intervention. Overall, this thesis provides justification for the
tests included and comprehensively examines the utility of this battery for assessing
the anthropometric and physical characteristics of rugby league players. Practically,
this battery of tests can be used by researcher and applied practitioners in rugby
league with an understanding of the reliability, validity and sensitivity of the tests along
with some factors that might influence the characteristics of players across a season
