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Long-Term Training-Induced Changes in Sprinting Speed and Sprint Momentum in Elite Rugby Union Players

Authors:
  • Rugby Canada
  • Canadian Sport Institute
  • Gabbett Performance Solutions

Abstract and Figures

Speed and sprint momentum are considered to be important physical qualities for rugby. The purpose of the study was to understand the development of these qualities in senior and junior international rugby players. In Part 1 of the study, a group of senior (n=38) and junior (n=31) players were tested for speed over 40 m. Initial Sprint Velocity (ISV), Maximal Sprint Velocity (MSV), Initial Sprint Momentum (ISM) and Maximal Sprint Momentum (MSM) were calculated using 10 m splits. In Part 2 of the study, a group of junior (n=12) and senior (n=15) players were tracked over a two year period for body mass, ISV, MSV, ISM and MSM. In Part 1, senior backs and forwards were not found to have significantly greater ISV and MSV than junior players but were found to have greater ISM and MSM. Forwards were found to have significantly greater ISM and MSM than backs but significantly lower ISV and MSV than backs. In Part 2, no significant differences were found over the two years between senior and junior players but greater effect sizes for juniors were generally found when compared to seniors for improvements in ISV (d=0.73 vs 0.79), MSV (d=1.09 vs 0.68), ISM (d=0.96 vs 0.54) and MSM (d=1.15 vs 0.50). Sprint momentum is a key discriminator between senior and junior players and large changes can be made by junior players as they transition into senior rugby. Speed appears to peak for players in their early twenties but sprint momentum appears to be more trainable.
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LONG-TERM TRAINING-INDUCED CHANGES IN
SPRINTING SPEED AND SPRINT MOMENTUM IN ELITE
RUGBY UNION PLAYERS
MATTHEW J. BARR,
1
JEREMY M. SHEPPARD,
1
TIM J. GABBETT,
2,3
AND ROBERT U. NEWTON
1
1
Center for Exercise and Sports Science Research, Edith Cowan University, Joondalup, Western Australia, Australia;
2
School of
Exercise Science, Australian Catholic University, Brisbane, Queensland, Australia; and
3
School of Human Movement Studies,
The University of Queensland, Brisbane, Queensland, Australia
ABSTRACT
Barr, MJ, Sheppard, JM, Gabbett, TJ, and Newton, RU. Long-
term training-induced changes in sprinting speed and sprint
momentum in elite rugby union players. J Strength Cond Res
28(10): 2724–2731, 2014—Speed and sprint momentum are
considered to be important physical qualities for rugby. The
purpose of the study was to understand the development of
these qualities in senior and junior international rugby players.
In part 1 of the study, a group of senior (n= 38) and junior (n=
31) players were tested for speed over 40 m. Initial sprint
velocity (ISV), maximal sprint velocity (MSV), initial sprint
momentum (ISM), and maximal sprint momentum (MSM) were
calculated using 10-m splits. In part 2 of the study, a group of
junior (n= 12) and senior (n= 15) players were tracked over
a 2-year period for body mass, ISV, MSV, ISM, and MSM. In
part 1, senior backs and forwards were not found to have
significantly greater ISV and MSV than junior players but were
found to have greater ISM and MSM. Forwards were found to
have significantly greater ISM and MSM than backs but signif-
icantly lower ISV and MSV than backs. In part 2, no significant
differences were found over the 2 years between senior and
junior players, but greater effect sizes for juniors were generally
found when compared with seniors for improvements in ISV
(d= 0.73 vs. 0.79), MSV (d= 1.09 vs. 0.68), ISM (d= 0.96 vs.
0.54), and MSM (d= 1.15 vs. 0.50). Sprint momentum is a key
discriminator between senior and junior players, and large
changes can be made by junior players as they transition into
senior rugby. Speed appears to peak for players in their early
20s but sprint momentum appears to be more trainable.
KEY WORDS acceleration, maximal sprint velocity, long-term
athlete development
INTRODUCTION
Speed is commonly considered to be a highly valu-
able ability in rugby union and a key component of
a team’s success (9). A notable difference between
specialist sprinters competing in track and field
and rugby players is the body mass. When examining his-
torical data of the body types of elite sprinters, it would
appear that there exists an optimal body mass for sprinters
(26,27,29) that is not likely optimal for rugby union players
(8). The mass differences between sprinters and rugby play-
ers are likely related to the various collisions in the game that
favor heavy body mass (7,18). An indicator of the continued
importance of size in rugby union has been the steady
increase in body mass of players over the history of the game
(16,22). The importance of both body mass and sprinting
speed in rugby may mean that the combination of the 2,
sprint momentum, is a more important determinant of suc-
cess in rugby union. Sprint momentum, calculated by mul-
tiplying sprinting velocity with body mass, has previously
been found to discriminate between performance levels of
elite rugby league players (4), but there is currently a gap in
the literature analyzing the importance of sprint momentum
in elite rugby union players. Elite rugby union players might
choose to play at a body mass that is not optimal for max-
imizing sprinting speed but optimizes sprint momentum.
However, the relationships between sprinting speed, mass,
and momentum and how they may discriminate between
playing levels of elite rugby players are currently unclear.
Previous research that has examined long-term changes in
strength and power in contact field-sport athletes such as
rugby union (1), rugby league (2,3), and American football
(12,15,24) players indicated that strength development can
continue throughout a playing career. Long-term changes in
the sprinting speed of American university football players,
however, suggest that the development of speed is much
more limited when compared with strength (15,24). It may
be possible that speed peaks very early as a physical quality
in contact field-sport athletes but sprint momentum contin-
ues to develop for a longer period of time as athletes con-
tinue to gain muscle mass (1). There are currently no
Address correspondence to Matthew J. Barr, mjbarr@our.ecu.edu.au.
28(10)/2724–2731
Journal of Strength and Conditioning Research
Ó2014 National Strength and Conditioning Association
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published studies that have examined whether or not elite
rugby union players improve sprint momentum and sprint-
ing speed over several years of training.
The purpose of the study was to understand the devel-
opment of the sprinting speed and sprint momentum in
senior and junior international rugby players. Three different
components of sprint momentum and sprinting speed were
specifically examined. First, we examined whether speed or
momentum could discriminate between senior and junior
international rugby union players. Second, we examined
whether or not junior rugby union players transitioning into
senior rugby develop sprint momentum and speed at greater
rates than senior rugby union players. Finally, we examined
the relationship between sprinting speed, sprint momentum,
and body mass. It was hypothesized that sprint momentum
but not speed would discriminate senior and junior union
players. It was hypothesized that junior players transitioning
into senior rugby would improve sprint momentum at
a greater rate than senior players and would close the sprint
momentum gap over 2 years. It was also hypothesized that
body mass would negatively affect sprinting speed but there
would be an optimal body mass for maximizing sprint
momentum.
METHODS
Experimental Approach to the Problem
To understand how sprint momentum and sprinting speed
are developed in elite rugby players, the study was divided
into 2 parts. The first part consisted of a causal-comparative
cross-sectional design and second part of the study was
a longitudinal quasi-experimental design. The first part of the
study consisted of determining sprinting velocity, sprint
momentum, and body mass of 69 junior and senior
international rugby players. The second part consisted of
tracking the changes in body, sprinting speed, and sprint
momentum of 28 international rugby union players over a
2-year period. Two-way and repeated-measure analyses
of variance (ANOVAs) were used to calculate differences
between the different conditions and groups. Correlations
were also calculated between mass, sprint momentum, and
sprinting velocity in part 1 and the changes in these qualities
over 2 years in part 2.
TABLE 1. Typical speed exercises used during
training (100–350 m per session total volume).
Flat sprints (10–60 m)
38Uphill sprints (10–20 m)
Resisted sled sprints (5–15 m)
38Downhill sprints (20–40 m)
Change of direction drills
TABLE 2. Differences in maximal sprint momentum, initial sprint momentum, maximal sprint velocity, and initial sprint velocity between senior and under-20
national team rugby forwards and backs.*
Initial sprint velocity
(m$s
21
)
Maximal sprint velocity
(m$s
21
)
Initial sprint momentum
(kg$m
21
$s
21
)
Maximal sprint momentum
(kg$m
21
$s
21
) Mass (kg)
Senior Junior Senior Junior Senior Junior Senior Junior Senior Junior
Forwards 5.49 5.50 8.30 8.40 613 555 925 845 111.7 101.0
SD 0.27 0.26 0.49 0.57 45 40 45 47 6.5 9.6
Backs 5.73 5.81 9.08 9.07 527 486 836 758 91.9 83.7
SD 0.24 0.26 0.48 0.33 50 44 84 60 6.6 7.8
Difference between under-20
and senior
p= 0.426, d= 0.17 p= 0.71, d= 0.09 p,0.0001, d= 0.81 p,0.0001, d= 0.95 p,0.0001, d= 0.75
Difference between forwards
and backs
p,0.0001, d= 1.04 p,0.0001, d= 1.4 p,0.0001, d= 1.68 p,0.0001, d= 1.45 p,0.0001, d= 1.95
*Differences, as calculated by a 2-way ANOVA and Tukey’s post hoc analysis, are listed below with pvalue and effect sizes (Cohen’s d).
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TABLE 3. Two year changes in mass, maximal sprint momentum, initial sprint momentum, maximal sprint velocity, and initial sprint velocity of senior and junior
national team players transitioning into senior international rugby.*
Mass (kg)
Initial sprint
velocity (m$s
21
)
Maximal sprint
velocity (m$s
21
)
Initial sprint
momentum
(kg$m
21
$s
21
)
Maximal sprint
momentum
(kg$m
21
$s
21
)
Pre Year 1 Year 2 Pre Year 1 Year 2 Pre Year 1 Year 2 Pre Year 1 Year 2 Pre Year 1 Year 2
Junior
Mean 92.2 93.6 96.6 5.59 5.80 5.79 8.64 8.97 9.14 514 541 558 795 839 881
6SD 8.8 8.3 9.7 0.28 0.26 0.21 0.46 0.45 0.42 46 36 45 74 78 80
Senior
Mean 94.6 95.9 95.9 5.53 5.74 5.71 8.65 8.87 8.92 522 550 548 817 849 854
6SD 8.6 9.2 8.4 0.23 0.21 0.22 0.39 0.45 0.50 47 53 51 75 86 82
Pre–
year 1
Year 1–
year 2
Pre–
year 2
Pre–year
1
Year 1–
year 2
Pre–
year 2
Pre–
year 1
Year 1–
year 2
Pre–
year 2
Pre–
year 1
Year 1–
year 2
Pre–
year 2
Pre–
year 1
Year 1–
year 2
Pre–
year 2
Junior
d0.16 0.33 0.50 0.75 0.02 0.73 0.73 0.37 1.09 0.58 0.43 0.96 0.58 0.50 1.15
p0.93 0.69 0.46 0.13 0.99 0.13 0.17 0.63 0.02 0.29 0.58 0.04 0.17 0.23 0.01
Senior
d0.15 0.01 0.16 0.92 0.14 0.79 0.55 0.10 0.68 0.59 0.04 0.54 0.43 0.06 0.50
p0.89 0.99 0.84 0.004 0.85 0.02 0.39 0.95 0.24 0.30 0.99 0.36 0.28 0.98 0.39
*Cohen’s effect sizes (d) and alpha (p) of differences from the initial testing to the end of the first year and second year are listed below.
Speed and Momentum of Rugby Players
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Subjects
The participants in the first part of the analysis (height,
1.84 60.1 m; body mass, 102.8 611.9 kg; age, 26.2 63.2 years)
were 38 senior national team players (21 forwards and 17
backs) from the same national team (typically 11th–15th
place in the International Rugby Board world rankings)
and 31 under-20 national team players (17 forwards and 14
backs) also from the same country’s national team (height,
1.84 60.1 m; body mass,
93.2 612.3 kg; age, 19.2 6
0.9 years). The participants in
the second part of the analysis
were 12 (4 forwards and 8
backs) junior national team
players (height, 1.85 60.07
m; body mass, 92.2 68.8 kg;
age 18.9 60.5 years) transition-
ing into senior rugby and 15 (6
forwards and 9 backs) senior
national team players (height,
1.83 60.06 m; body mass,
94.6 68.6 kg; age, 24.1 62.3
years). All of the junior players
were playing under-20 national
team players at the beginning
of the study and had played
senior international rugby (IRB
test match or A match) by the
end of the study. All of the par-
ticipants involved in the study
were training on a full-time basis
at a national team training acad-
emy. Each of the participants
was typically involved in
approximately 8–12 weeks per
year of national team duty, 24
Figure 1. Differences in maximal sprint momentum (A), initial sprint momentum (B), maximal sprint velocity (C),
and initial sprint (D) between senior and under-20 national team rugby forwards and backs. Senior group results
are in black and under-20 players are in white. Asterisk denotes a significant difference (p#0.05) between senior
and under-20 players. Dashed line denotes a significant difference (p#0.05) between forwards and backs.
TABLE 4. Pearson’s correlations between momentum, velocity and mass in elite rugby players (n= 69).
Initial sprint velocity (m$s
21
)
0.83 Maximal sprint velocity (m$s
21
)
20.15 20.40 Initial sprint momentum (kg$m
21
$s
21
)
20.09 20.17 0.93 Maximal sprint momentum (kg$m
21
$s
21
)
20.52 20.68 0.92 0.84 Mass (kg)
TABLE 5. Pearson’s correlations between changes in momentum, velocity and mass in elite rugby players over
2 years (n= 27).
Initial sprint velocity (m$s
21
)
0.04 Maximal sprint velocity (m$s
21
)
0.59 20.04 Initial sprint momentum (kg$m
21
$s
21
)
20.01 0.63 0.57 Maximal sprint momentum (kg$m
21
$s
21
)
20.02 20.07 0.80 0.73 Mass (kg)
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weeks per year of club rugby, 12–16 weeks per year of pre-
season training, and 4 weeks of rest. Training during national
team competition weeks involved 1–2 strength training ses-
sions and 3–4 rugby practices per week. Training during club
rugby competition weeks typically involved 2–3 strength train-
ing sessions, 1–2 speed training sessions, and 2–3 rugby prac-
tices per week. Training during preseason training typically
involved 2–3 speed training session, 3–4 strength training ses-
sions, and 1–2 rugby practices per week. Given the intense
nature of rugby, each player was injured at some point
of the study so that their training had to be modified, but
no players were injured to an extent that long-term layoffs
(.1 month) occurred. Each participant was following their
own individualized training program, but typical sprint training
sessions were based on the exercises listed in Table 1. Strength
training sessions typically consisted of variations of the Olym-
pic lifts, squats, pressing exercises, upper-body pulling exer-
cises, plyometrics, and other exercises. Each session typically
consisted of 4–6 exercises performed for 5–8 sets of 1–8 rep-
etitions. Each participant gave written informed consent, and
the study had Institutional Review Board approval.
Procedures
Each of the players performed four 40-m sprints on an
artificial field using a Brower (Brower Timing Systems,
Draper, UT, USA) system with timing gates placed on 1 m
high tripods at 0, 10, 30, and 40 m. The players began each
sprint with their front foot beside a cone 0.75 m behind the
first gate. The order of the trials was randomized for each
subject to balance the possible effects of fatigue. Each subject
completed at least 1 trial of each condition before their
second round where they completed trials in the same order.
A rest time of 4–5 minutes was given between each trial. The
fastest 0- to 10- and 30- to 40-m splits were kept for analysis.
The 0- to 10-m split is representative of acceleration ability,
and the 30- to 40-m split is representative of maximal veloc-
ity (6). Velocity scores (m$s
21
) were calculated for both of
these splits by dividing the 10-m split by the time taken to
complete the trial. The 0- to 10-m split was defined as initial
sprint velocity (ISV) and the 30- to 40-m split as maximal
sprint velocity (MSV). The mass of the athlete was multi-
plied by both velocity scores (kg$m
21
$s
21
) to obtain an
initial sprint momentum (ISM) and maximal sprint momen-
tum (MSM) score. Mass, height, and sum of 7 skinfolds
(bicep, tricep, subscapular, abdominal, supraspinale, front
Figure 2. Two-year changes in mass (E), initial sprint velocity (D),
maximal sprint velocity (C), initial sprint momentum (B), and maximal
sprint momentum (A) of senior international rugby players and junior
rugby players transitioning into senior international rugby. Senior players
are denoted with solid bars and junior players transitioning into senior
rugby are denoted with dashed bars. Error bars denote SD.
Figure 3. Relationship between body mass and maximal sprint
momentum (solid diamonds, top graph), initial sprint momentum (open
circles, top graph), maximal sprint velocity (solid diamonds, bottom
graph), and initial sprint velocity (open circles, bottom graph).
Speed and Momentum of Rugby Players
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thigh, and medial calf) of the athletes were tested using the
protocol of the International Society for the Advancement of
Kinanthropometry (23) by an ISAK-certified tester (level 2).
Statistical Analyses
Reliability for ISV and MSV was determined to be very
reliable with intraclass correlations of r= 0.91 and r= 0.94.
To compare mass, momentum, and velocity differences
between under-20 and senior players in part 1, a 2-way
(positional 3age group) ANOVA was used. To compare
changes in mass, momentum, and velocity differences
between under-20 and senior players in part 2, a 2-way
repeated (time 3age group) ANOVA was used. The level
of significance was set at p#0.05. If a significant Fvalue was
found, then a Tukey’s post hoc test was used to determine
the source of these differences. Complete data sets of sum of
7 skinfolds were only available for the beginning of the
2-year period and the end of the 2-year period, so a paired
t-test was used to compare them. Pearson’s correlations
were calculated to characterize the relationship between
sprinting velocity, sprint momentum, and mass. To charac-
terize the differences between groups, Cohen’s deffect sizes
were calculated. The following classification system was
used to determine the magnitude (13) of Cohen’s deffect
sizes, effect sizes were considered trivial for being ,0.2, small
for $0.2 and ,0.6, moderate for $0.6 and ,1.2, large
for $1.2 and ,2.0, and very large for .2.0. An alpha
of p#0.05 was set for level of significance for ANOVAs.
All statistical analyses were conducted using XLSTAT
(Addinsoft, NY, USA) software.
RESULTS
In part 1, moderate differences in ISM (mean difference:
49 kg$m
21
$s
21
,p,0.0001, Cohen’s d= 0.81) and MSM
(79 kg$m
21
$s
21
,p,0.0001, d= 0.95) were found between
senior and under-20 players. Trivial differences in ISV (p=
0.426, d= 0.17) and MSV (0.05 m$s
21
,p= 0.71, d= 0.09)
were found between senior and under-20 players. Very large
correlations were found between mass and MSM (r= 0.84)
as well mass and ISM (r= 0.92). Large correlations were
found between ISV (r=20.52) and MSV (r=20.68). In
part 2, no significant differences were detected between the
senior and junior groups at any of the time points. The junior
group made large improvements in MSM (mean change:
86 kg$m
21
$s
21
,p= 0.03, d= 1.15) and MSV (0.5 m$s
21
,
p= 0.02, d= 1.09) and moderate increases in ISM
(44 kg$m
21
$s
21
,p= 0.04, d= 0.96) and ISV (0.2 m$s
21
,
p= 0.13, d= 0.73) over the 2 years. The changes in the
senior group were considerably lower with moderate im-
provements in ISV (0.18 m$s
21
,p= 0.02, d= 0.79), MSV
(0.27 m$s
21
,p= 0.24, d= 0.68), ISM (26 kg$m
21
$s
21
,p=
0.36, d= 0.54), and MSM (37 kg$m
21
$s
21
,p= 0.42, d=
0.50). Trivial differences (p= 0.92, d= 0.02) were found
for changes in sum of 7 skinfolds between the pretesting
period (65.8 620.0 mm) and end of the 2-year period
(66.3 618.4 mm) in the combined group of junior and
senior players (Tables 2–5; Figures 1–3).
DISCUSSION
The similarity of sprinting speed but significant difference of
mass and momentum between senior and junior players in
part 1 are consistent with a previously reported comparison
of elite junior and senior players (10) that showed differences
in body mass but not sprinting speed. The differences in
mass between forwards (;11 kg) and backs (;8 kg) in part
1 could indicate that this is a normal amount of mass for
junior players to put on as they progress into senior rugby
and they do so without increasing sprinting speed. The dif-
ferences in mass and momentum between the 2 age groups
could also have been skewed by junior players who do not
have the frame to carry large amounts of muscle mass and
will not progress onto senior rugby. Height was equivalent
between the 2 groups but skeletal dimensions were not mea-
sured so this is unknown. The junior players transitioning
into senior rugby did put on mass over 2 years (4.4 kg) but it
was much less than the differences between the 2 age groups
in part 1.
The cross-sectional data from part 1 and the study of
Hansen et al. (10) might cause coaches to conclude that
speed is not improved past 19 years of age because there
was no difference in speed between juniors and seniors. The
data from part 2 of this study provide strong evidence that
sprinting speed, sprint momentum, and mass can all be
improved with senior and junior players but junior players
do have a greater window of adaptation for developing these
qualities. No differences at any of the time points were de-
tected between the senior and junior groups but the differ-
ences in effect sizes of the groups show that the senior group
was near exhausting their potential of speed and sprint
momentum improvement. The junior group made greater
changes in the different sprint qualities when compared with
the senior group with the exception of ISV that was similar
between the 2 groups (Table 3; Figure 2). These results show
that large changes can be made in all of the different sprint
qualities in junior players transitioning into senior rugby but
the greatest changes can be made in MSM. The strength and
speed training (Table 1) that all of the players undertook
likely influenced the athletes’ ability to increase sprinting
speed and sprint momentum. The heavy squatting, pressing,
and pulling exercises were likely helpful for increasing body
mass (1,5), and the emphasis on power exercises (5,11,19,25)
and sprint-specific training methods (17,28) were likely able
to improve the ability to develop the large but brief forces
(14,29) necessary for maximal speed sprinting. Improving
sprint momentum is likely somewhat more complex than
improving sprinting speed as there are simultaneous goals
of increasing muscle mass but improving the ability to
develop mass-specific forces in a briefer time period. It could
be inferred from the improvements in sprint momentum and
sprinting velocity that the strength and speed exercises used
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in this study, at least in junior players, are successful for this.
The smaller improvements in senior players in the first year
and negligible improvements in the second year may indi-
cate a few different things. It may indicate that the technique
and neuromuscular changes that can improve sprinting
speed (20) were possibly exhausted in these athletes, and
no further improvements could be made. Alternatively, the
exercises or training frequencies were inadequate for improv-
ing performance. Another possibility is that the extensive
training background of the athletes may mean that larger
gains must be made in training activities to observe notewor-
thy gains in sprint activities.
A hypothesis of this study was that body mass would
negatively affect sprinting speed. Body mass in part 1 was
found to have a stronger negative association with MSV
(r=20.68) than with ISV (r=20.52) (Figure 3). This
finding is in agreement with research that suggests that
MSV is limited by the ability to develop mass-specific forces
in a briefer period of time (30), but higher body masses
negatively affect the ability to develop mass-specific forces
(21). The mass of the players in part 1 of this study (101.7 6
11.8 kg) was considerably higher than the narrow range of
body masses (77.0 66.6 kg) reported by Uth (26). If speed
was the only key physical ability for rugby players, then the
implication would be that players should focus on lowering
their body mass. The small changes in mass of the players
over 2 years, however, did not negatively affect their
sprinting velocity (Tables 3 and 5), so these results would
support the idea that small gains in mass can be made with-
out compromising improvements in sprinting speed. The
correlations between the changes in mass with ISV (r=
20.02) and MSV (r=20.07) over 2 years were very weak,
which means that it is a safe assumption that increasing
muscle mass to increase sprint momentum will not nega-
tively affect sprinting velocity.
Given the number and intensity of collisions in rugby,
maximizing sprint momentum likely needs be a key focus for
training rugby players. In part 1, a very large correlation
(Figure 3) was found between mass and both ISM (r= 0.92)
and MSM (r= 0.84). It could be concluded from this that
there is a compromise between maximizing sprint momen-
tum and maximizing sprinting velocity as mass positively
affects one (momentum) and negatively affects the other
(velocity). The longitudinal data from Table 5 indicate that
increasing mass has the greatest effect on increasing ISM
(r= 0.80) and MSM (r= 0.73), but the increases in momen-
tum also correspond to increases in ISV (r= 0.59) and MSV
(r= 0.63). This means that the sprint momentum of elite
rugby players can be increased by developing both body
mass and sprinting speed. It may be possible that excessively
increasing body mass will negatively affect sprinting speed
but positively affect sprint momentum. Maximizing momen-
tum through increasing body mass is likely important for
players whose position involves ball carrying in situations
where contact is unavoidable (tight 5 players, etc.), and
maximizing sprinting speed by minimizing body mass is
more important for players where carrying a ball at maximal
speed is normal and contact is somewhat avoidable (wingers,
etc.). This is supported by the fact that in part 1, forwards
were slower for both ISV (mean difference: 20.28 m$s
21
,
p,0.0001, d= 1.04) and MSV (20.72 m$s
21
,p,0.0001,
d= 1.4) but had higher levels of ISM (77 kg$m
21
$s
21
,
p,0.0001, d= 1.68) and MSM (88 kg$m
21
$s
21
,p,
0.0001, d= 1.45). The relationship between sprint momen-
tum, body mass, and sprint velocity would suggest that posi-
tional ideal standards should be set and all 3 scores need to
be considered when testing.
Given the importance of sprint momentum for rugby
union, it would be beneficial for future research to assess the
impact of players improving sprint momentum. It would be
worthwhile to know if the ability to gain mass and increase
sprint momentum differentiates players who are successful in
advancing to higher levels of competition from their peers
who do not progress to higher levels. Additionally, it would
also be interesting to know whether an increase in sprint
momentum leads to individual improvements in perfor-
mance during games. For instance, an off-season training
program resulting in an increase in sprint momentum could
lead to more effective tackles while on defence and more
tackle breaks (31) while on offense during the following
season.
PRACTICAL APPLICATIONS
Improving sprint momentum is likely a key component of
physical preparation for rugby. Monitoring sprint momen-
tum, and not just sprinting speed, should be a key focus for
strength and conditioning coaches working with rugby
players. Measuring sprint times with 10-m splits allows for
coaches to consider both sprinting speed and sprint
momentum qualities. This allows for coaches to track
meaningful changes in performance while considering
improvements in both lean body mass and sprinting speed.
Positional standards for both momentum and speed should
be developed and be set as targets when planning training
programs. The window for adaptation in developing sprint
momentum and sprinting speed is likely greater for players
in their late teens and early 20s when compared with players
in their mid-to-late 20s. Developing sprint momentum and
sprinting speed should, thus, be a key focus with this age
group. To increase sprint momentum, strength training likely
needs to consist of exercises that will increase both muscular
hypertrophy and power. These exercises also need to be
combined with different sprint training methods, so an
increase in body mass does not negatively affect sprinting
speed.
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... 160 Sprint momentum appears to be more trainable than sprint velocity; with maximum sprinting speed 161 tending to peak for rugby union players in their mid-20s. In contrast, sprint momentum continues to 162 improve amongst academy and elite senior rugby players in association with increased body mass 163 (5,15). A novel aspect of one recent study is the inclusion of simple regression analysis to predict the 164 level of change in a physical measure necessary to improve an associated game statistic (14). ...
... Furthermore, sprint 168 momentum is an underreported measure within the literature, with some studies failing to present the 169 relationship between sprint momentum and ball-carrying capability despite reporting measurements of 170 body mass and sprint times over 10 m, 20 m, and 30 m (53). The window for adaptation in the 171 development of sprint momentum has been shown to be greater for players in their late teens and early 172 20s when compared with players in their mid-to-late 20s (5). As sprint momentum has been reported to 173 be a strong indicator of ball-carrying capability amongst international rugby union players, particularly 174 the backs (14), developing sprint momentum should be a key focus in the physical preparation of players 175 within this age category (5,15). ...
... The window for adaptation in the 171 development of sprint momentum has been shown to be greater for players in their late teens and early 172 20s when compared with players in their mid-to-late 20s (5). As sprint momentum has been reported to 173 be a strong indicator of ball-carrying capability amongst international rugby union players, particularly 174 the backs (14), developing sprint momentum should be a key focus in the physical preparation of players 175 within this age category (5,15). To increase sprint momentum, physical training will likely need to 176 consist of exercises that will promote muscular hypertrophy and maintain maximum sprint velocity 177 (5,15). ...
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... Casserly et al. (2020) reported that smaller junior players must undergo increases in body mass (BM) to achieve senior professional status. This has important implications for rugby practitioners, since BM has been shown to have a detrimental effect on high-intensity running , endurance capacity and sprint speed and momentum (Barr et al., 2014). As such, coaches need to carefully balance improvements in physical qualities with simultaneous improvements in the anthropometric profiles of adolescent players (Casserly et al., 2020). ...
... Given the fact that sprinting speed and SM are considered relevant abilities in rugby union (Barr et al., 2014), monitoring changes across an entire season should be considered by coaches and practitioners. Remarkably, this is the first study to track changes in several speed-related parameters (e.g. ...
... split times, Vmax, SM max , SM ini ) across an entire competitive season in youth amateur rugby union players. To the best of our knowledge, only Barr et al. (2014) tracked the changes in similar variables in a group of junior players (i.e. U20) transitioning into senior rugby over a two-year period; however, the authors did not discriminate their analysis by playing position. ...
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... Among various performance components, improvement of speed for the players having extensive training experience becomes most challenging to the coach and trainer. In this direction; the coaches who are working with traditional training methods faced a plateau (Barr et al., 2014) called speed barrier for further improvement of sprinting speed after reaching up to certain level eliciting no further training adaptation (Barr et al., 2015).Very often, a well-trained athlete has reached a speed plateau, in which his or her training no longer yields faster speeds. This stabilization of the athlete's speed qual- ities is the speed barrier. ...
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... 32 Forwards have a higher body mass, muscle mass and strength compared with backs, whereas backs have less body and muscle mass, possess higher levels of aerobic fitness and are faster than forwards. 5,27,39 The distinct differences in positional demands and activity of forwards versus backs on the Rugby field suggest that variations in injury incidence and trends are likely. In Rugby league, variations in injury nature, site, and mechanism of injury were evident when analyzing injury data by playing position. ...
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... One of the most interesting findings of the study was that when the sprint time and sprint speed of these groups were examined, there was no significant difference compared to the balanced mesomorphic groups, but significant differences were found observed in the momentum data. The similarity in sprint speed but the significant difference in sprint momentum between somatotype groups are consistent with previous studies [37,38]. When calculating sprint momentum, the possibility that differences in somatotype directly affect momentum was strengthened by considering sprint speed along with body mass. ...
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... Moreover, it is also plausible that incoming SKILL trained acceleration more and earlier compared with incoming LOS. If true, further SKILL improvement would likely be attenuated because of diminishing returns compared with LOS (5). ...
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Baur, DA, Johnson, JB, Giron-Molina, LG, Caterisano, M, Shaner, C, Caterisano, A, and Gentry, M. Career-best changes in body mass and physical fitness test performance among Division 1 college football players encompassing 28 years at the same institution. J Strength Cond Res XX(X): 000-000, 2022-Understanding typical changes induced by collegiate American football strength and conditioning programs is essential for optimizing program design and athletic development. The purpose of the study was to evaluate body mass and physical fitness test performance changes at a Division 1 program with 28 years of coaching stability. Initial and personal record results were collected from 1,102 players who were subdivided into 3 position groups: combination players (COMBO), skill players (SKILL), and line of scrimmage players. Players followed a linear periodized training program with biannual body mass and performance testing. Tested variables included body mass, strength (bench press, back squat, and front squat), impulse (power clean, push jerk, and vertical jump [VJ]), and speed/agility (10-yard dash [10YD], 40-yard dash, and 20-yard shuttle). The fixed effect of time and position group on the dependent variables was assessed using linear mixed models. If appropriate, post hoc tests using the estimated marginal means were used to evaluate the source of any significant effects. Significance was accepted as p < 0.05. Normative values were produced by descriptive statistics (i.e., weighted means). All players and position groups increased/improved across all tested variables (p < 0.05). Improvements were 8.2%, 11.9-18.3%, 13.5-17.5%, and 3.6-6.0% for body mass, strength, impulse, and speed/agility, respectively. Line of scrimmage improvements were absolutely larger across most tested variables and relatively larger for back squat, VJ, and 10YD vs. SKILL and with VJ vs. COMBO/SKILL (p < 0.05). These results reveal typical expectations for 4-5 years performance improvements and that position group differences in trainability may influence game readiness and training needs.
... high intensity running, endurance capacity, sprint speed, and momentum). [75][76][77] Moreover, recently Weldon et al. 55 revealed that body composition was the most common physical test implemented by SCCs across professional sports. This is the first study to describe the use of technology in rugby union, which naturally limits additional comparisons. ...
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Purpose The aims of the present study were two-fold: (i) to investigate the relationship between physical characteristics and the game statistics associated with ball-carrying capability amongst sub-elite rugby union players, and (ii) to predict the level of change in these physical characteristics required to improve the associated game statistic via regression analysis. Methods Thirty-eight senior professional players (forwards, n = 22; backs, n = 16) were assessed for body mass (BM), back squat (BS) single-repetition maximum (1RM) normalised to BM (1RM/BM), 10 m sprint velocity (S10), 10 m sprint momentum (SM10), and the game statistics from 22 games within the 2019/20 RFU Championship season. The relationship between these measures and the predicted level of change in a physical measure required to improve the total number of the associated game statistic by one were assessed by Pearson’s correlation coefficient and simple regression analyses. Results In forwards, an ~ 11.5% reduction in BM, an ~ 11.8% improvement in BS 1RM/BM, or an ~ 11.5% increase in S10 was required to improve the game statistics associated with ball-carrying capability. In backs, a ~ 19.3% increase in BM or a ~ 15.6% improvement in SM10 was required. Conclusions These findings demonstrate that improvements in lower-body relative strength, acceleration performance, and position-specific alterations in body mass are required to maximise the ball-carrying capability and therefore match outcome of sub-elite rugby union players.
Article
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Chapter
Although rugby is a contact collision sport, in all its codes the sport involves considerable running activity. Although backs may be perceived to do more high-speed running and sprinting, however forwards often undertake considerable sprinting more frequently from a standing start and with greater weight leading to higher momentum. High-intensity and sprint training must be specific for players of all positions.
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The purpose of this study was to characterize the sprinting kinematics of elite rugby players as they transition from a standing start to maximal velocity. A group of players (n=11) underwent an assessment of their sprinting ability by performing four 50 m sprints. All players (height = 1.86 ± 0.08 m, mass = 100 ± 9 kg) had played senior international rugby. Each of the sprints was filmed using Nikon J1 video cameras recording at 400 f/s at the 3 m, 9 m, 15 m, 21 m, 27 m, 33 m, 39 m, and 45 m marks of the 50 m sprints. Stride length, stride rate, ground contact time, flight time and velocity were calculated using a computer program (Kinovea). Velocity peaked at either the 33 m or 39 m mark with significant differences in velocity between the 33 m mark and velocities at 3 m, 9 m and 15 m marks (P<0.05 - P<0.0001). Ground contact time at the 3 m mark was significantly longer than at every other distance measured (P<0.0001). Stride length was significantly shorter at the 3 m (P<0.0001) than every other section. Stride length and ground contact time at 9 m were significantly different from every other distance except for 15 m. No differences were found in stride rate between any of the distances. Elite rugby players achieve their top speed between 30 m and 40 m and do so by decreasing ground contact time and increasing stride length as they accelerate.
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In an attempt to develop a new measure of agility in the horizontal plane, this study examines several tests, including: the Illinois agility test, the 20m dash and two new tests - the Up and Back (UAB) and 505 tests, which both involve a short sprint and a reversal of direction. Eighteen subjects performed the tests in a randomised order. A strobe video and time were used to record the displacement data of the subjects, over set intervals, in the UAB and 505 tests. These data were then smoothed using a least-squares polynomial, and differentiated to produce a velocity and acceleration values. Times were recorded for the completion of the Illinois agility test and the 20m dash. The results for the four tests and the derived velocity and acceleration values were subjected to a correlation matrix. Significant correlations were found between the 505 test and acceleration values, but not with velocity values. The other tests correlated significantly with each other. It is concluded that the UAB test and Illinois Agility test are not purely agility tests because of their significant relationships with the 20m dash. The 505 test, however, has no significant correlation with velocity, but rather with acceleration. Therefore, the 505 test is seen as the test which best isolates agility in the horizontal plane.
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The present study compared the anthropometry of sprinters and people belonging to the normal population. The height and body mass (BM) distribution of sprinters (42 men and 44 women) were statistically compared to the distributions of American and Danish normal populations. The main results showed that there was significantly less BM and height variability (measured as standard deviation) among male sprinters than among the normal male population (US and Danish), while female sprinters showed less BM variability than the US and Danish normal female populations. On average the American normal population was shorter than the sprinters. There was no height difference between the sprinters and the Danish normal population. All female groups had similar height variability. Both male and female sprinters had lower body mass index (BMI) than the normal populations. It is likely that there is no single optimal height for sprinters, but instead there is an optimum range that differs for males and females. This range in height appears to exclude people who are very tall or very short in stature. Sprinters are generally lighter in BM than normal populations. Also, the BM variation among sprinters is less than the variation among normal populations. These anthropometric characteristics typical of sprinters might be explained, in part, by the influence the anthropometric characteristics have on relative muscle strength and step length. Key PointsThe male sprinters were less variable in height, body mass and body mass index than the normal populationsThe sprinters were lighter than the normal populations.The sprinters were taller than the American normal population.The female sprinters were less variable in body mass and body mass index than the normal population.
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Baker, DG. 10-year changes in upper body strength and power in elite professional rugby league players-The effect of training age, stage, and content. J Strength Cond Res 27(2): 285-292, 2013-The purpose of this investigation was to observe changes in maximal upper body strength and power across a 10-year period in professional athletes who were experienced resistance trainers. Six professional rugby league players were observed with test data reported according to 2 important training stages in their professional careers. The first stage (1996-1998) monitored the changes as the subjects strived to establish themselves as elite professionals in their sport. The remaining test data are from the latter stage (2000-2006), which is characterized by a longer competition schedule and shorter periods devoted to improving physical preparation. The changes in upper body strength, assessed by the 1 repetition maximum bench press and mean maximum power during bench press throws with various barbell resistances of 40-80 kg, were assessed by effect size (ES) and smallest worthwhile change (SWC) statistics. Large increases in strength and power of approximately 22-23% were reported across the 10-year period, however, only small changes (as determined by ES) in strength or power occurred after year 2000 till 2006. This result of only small changes in strength or power despite 6 years of intense resistance training was attributed to 3 main factors. Key among them are the possible existence of a "strength ceiling" for experienced resistance trainers, the Long-term Athlete Development model, and possibly an inappropriate volume of strength-endurance training from 2004 to 2005. The fact that an SWC in strength and power occurred in the year after the cessation of strength-endurance training suggests that training program manipulation is still an influencing factor in continuing strength and power gains in experienced resistance trainers.
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Contact skills are fundamental attributes of performance in rugby union. This study explored how the qualities of contact intensity and fending strategies related to tackle outcome in rugby union. Seven Super 14 games were coded using numerous quantitative and qualitative variables that assessed team patterns and individual skill execution during attacking ball carries. A variety of contact skills were shown to contribute significantly to the prediction of tackle-breaks. It was shown that 92% of tackle-breaks occurred as a result of poor defensive positioning. In addition, strong contact intensity and active fending strategies predicted 86% of poor defensive positions. Notably, active fend strategies were associated with positive phase outcomes when running straight at the defence and when using evasive methods of attack. This study provided critical insight regarding how the qualities of contact intensity and fending strategies influence effective ball carries in rugby union.