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The Youth Physical
Development Model:
A New Approach to
Long-Term Athletic
Rhodri S. Lloyd, PhD, CSCS*D
and Jon L. Oliver, PhD
Faculty of Applied Sciences, University of Gloucestershire, United Kingdom; and
Cardiff School of Sport, Cardiff
Metropolitan University, United Kingdom
have shown an increasing interest in
the long-term development of young
athletes (7,23 ,30,4 4,6 3,65,8 0 ,100,10 2).
Enhancing the physical abilities of chil-
dren throughout childhood and adoles-
cence to maximize athletic success at an
adult age is not a novel concep t, as
evidenced by earlier youth-based train-
ing programs (20). Researchers have
previously documented the importance
of not treating children like ‘‘miniature
adults’’ owing to clear differences in
physical growth and stature (39). T here-
fore, the content and delivery of youth
strength and conditioning provision
should be markedly different from that
of fully matured adults.
The long-term athlete development
(LTAD) model (7) takes into consider-
ation the maturational status of the
child and offers a more strategic
approach to the athletic development
of youth. The LTAD model suggests
that there exist critical ‘‘windows
of opportunity’’ during the develop-
mental years, whereby children and
adolescents are more sensitive to
training-induced adaptation (7). The
model also states that a failure to use
these windows will result in the
limitation of future athletic potential
(7). However, this concept is largely
theoretical and lacks supporting longi-
tudinal empirical evidence (4,44,84).
This article will present a new model,
which provides a more considered and
evidence-based approach to the long-
term development of young athletes.
The model will demonstrate that most,
if not all, components of fitness are
trainable throughout childhood and
will question some preconceptions of
current LTAD theory.
Early attempts at objectifying the
process of LTAD were based on
research that highlighted distinct
phases of learning that characterized
the development of elite performers:
the early years, the middle years,
and the later years (18). This early
work was extended by Cote (32) who,
after interviewing elite junior athletes,
identified 3 distinct spo rt-specific
stages of development: the sampling
years (ages 6–12 ), the specializing
years (ages 13– 15), and the invest-
ment years (ages 16+). A co mmon
problem with these models is that
they are classified in accordance with
chronologic age, an approach that has
previously been deemed flawed (44),
pediatrics; maturation; long-term
athlete development
Copyright ! National Strength and Conditioning Association Strength and Conditioning Journal |
owing t o differential rates of devel-
opment of chronologic age and
biologic maturity (57,68,108).
Consequently, a more comprehensive
LTAD model was introduced that
attempted to address the interaction
between growth, maturation, and
training (7). The model suggests that
measures of height and weight are
routinely collected to be able to
identify peak height velocity (PHV)
and peak weight velocity (PWV),
which reflect individual maturation
rates (68). PHV refers to the maximum
velocity of growth in stature and has
been used to characterize develop-
ments in performance relative to the
adolescent growth spurt (68). PWV is
a phase of development characterized
by rapid increases in muscle mass as
a result of increasing sex hormone
concentrations (44). By objectively
measuring the rates of change in height
and body mass, it is suggested that
children can be trained according to
biologic status as opposed to chrono-
logic age (7).
A review article by Viru et al. (110)
examined developmental literature and
identified the existence of naturally
occurring periods of accelerated adap-
tation for a range of biomotor qualities.
A preadolescent spurt was highlighted
for strength, speed, explosive strength,
and endurance, in both boys and girls
(110). It was suggested that age -related
developments in neural properties were
responsible for the prepubertal window,
characterized by increased intramuscu-
lar and intermuscular coordination and
improvements in motor control pro-
grams (110). An adolescent spurt was
also identified in the review, but this
differentiated between biomotor quali-
ties (110). Maturity-related adaptations
are typically the result of increased
androgen concentrations, fiber-type dif-
ferentiation, resting adenosine triphos-
phate, and creatine phosphate levels
and further architectural development
of musculotendon units (73).
Viru et al. (110) identified that spurts in
speed and endurance occurred before
and around PHV, respectively,
whereas accelerated gains in strength
qualities occurred after PHV (110).
Using PHV as a key reference marker
of maturation, the LTAD model pro-
poses that these periods of accelerated
adaptation offer windows of opportu-
nity where training responses will be
maximized (7). In the LTAD model, it
is assumed that these periods of rapid
natural development represent a time
of increased sensitivity to training,
although empirical evidence support-
ing this suggestion is lacking (44).
Furthermore, according to the LTAD
model, should a child not engage in the
appropriate training during the specific
window, then their ceiling potential
may never be reached. This concept
would appear to be too simplistic
and has recently been questioned
by researchers (4,44,85). Conversely,
research would suggest that most
fitness components are trainable
throughout childhood and should not
be restricted to specific ‘‘windows’’
at various stages of development
(3,44,94). Another weakness of the
current LTAD model (7) is that its
inclusion of stamina, suppleness, speed,
strength, and skill presents a somewhat
limited approach to the holistic
development of young athletes.
Despite the importance of power,
agility, and hypertrophy to human
performance (56,98,120), no guidance
is offered as to when and why these
qualities should be trained throughout
childhood and adolescence.
Given the limitations of previous
athletic development models, the pres-
ent article introduces a new alternative
model that encompasses athletic
development from early childhood
(2 years of age) up to adulthood (21+
years of age). The model has been
titled the Youth Physical Development
(YPD) model and offers a comprehen-
sive approach to the development of
young males (Figure 1) and females
(Figure 2), respectively. It is expected
that the new model will provide
strength and conditioning coaches,
sports coaches, physical educators,
and parents with an overview of total
physical development, while identify-
ing when and why the training of
each fitness component should be
Within the model, training emphasis is
highlighted by increasing font size
(i.e., the greater the font size, the
more important it is to train for that
fitness quality). For example, the model
shows that a 12- to 13-year-old boy
should primarily focus their training
on strength, power, speed, agility, and
sport-specific skill (SSS) development,
with a reduced focus on hypertrophy,
mobility, fundamental movement skill
(FMS), endurance, and metabolic
conditioning. Discussion of how mat-
urational status, sex, and initial train-
ing level affect the application of
the mode l will be discussed later in
the article. Below is a detailed over-
view of the rationale behind the
emphasis of targeting various fitness
components at different stages of
The topi c of FMS development has
received considerable interest owing
to the close association between
FMS competency, health and well-
being, physical activity, and to
(29,38,66,82,8 3,103). Previous rese -
arch has indicated that F M S devel-
opment is essential t o ensure that
correct movement patterns are mas-
tered in a safe and fun environment
to ensure safe and effective p erfor-
mance of more complex sports
movements at a later stage (85).
FMSs have been viewed as the
building blocks for sport-specific
movement patterns and should typ-
ically be the focus of physical devel-
opment programs for children from
early childhood to develop gross
m otor skills (35). From the onset of
puberty, adolescents can then be
introduced to more S S Ss, whereby
FMSs are tested within more com-
petitive scenarios.
VOLUME 34 | NUMBER 3 | JUNE 2012
Youth Physical Development Model
However, it must be noted that FMS
should always be present within any
strength and conditioning program, for
any athlete, of any age (65). For
example, the main emphasis of a train-
ing session for an inexperienced 7-year-
old boy may revolve around a series of
FMS development exercises, whereas
a young, elite, 21-year-old man may
integrate FMS maintenance exercises
within a dynamic warm-up. This
logical approach is reflected in the
YPD model (Figures 1 and 2), where
an emphasis is placed on FMS devel-
opment up to the onset of puberty, and
subsequently, focus is given to SSS
from adolescence onward. However,
the YPD model also shows that both
FMS and SSS are present at all times
throughout childhood and adoles-
cence, but the emphasis placed on
both components varies according to
developmental stage.
Despite previous concerns, it is now
accepted that children can safely and
effectively participate in strength train-
ing, when prescribed and supervised by
appropriately qualified personnel
(6,11,39,62,88,105). The LTAD model
(7) suggests that a ‘‘window of oppor-
tunity’’ for strength development in
youths occurs 12–18 months after
PHV, which is typically commensurate
with PWV (14,15). The rationale
behind this window is that around
the time of PWV, adolescents will
undergo periods of rapid gains in muscle
mass resulting from increased circulat-
ing androgen concentrations (110).
However, by limiting the period of
trainability to coincide with maturity-
related increases in muscle mass would
suggest that children can only become
stronger as a consequence of muscle
fiber hypertrophy and subsequent
increases in muscle cross-sectional
area. Despite this, it has previously
been established that strength devel-
opment is multifaceted and results
from a combination of muscular,
Figure 1. The YPD model for males. Font size refers to importance; light blue boxes refer to preadolescent periods of adaptation,
dark blue boxes refer to adolescent periods of adaptation. FMS = fundamental movement skills; MC = metabolic
conditioning; PHV = peak height velocity; SSS = sport-specific skills; YPD = youth physical development.
Strength and Conditioning Journal |
neural, and mechanical factors (1,34).
Owing to the neural plasticity associ-
ated with the prepubertal years, where
development of the neuromuscular
system naturally accelerates (21), it is
suggested that strength development
should be targeted during childhood in
addition to after the adolescent spurt.
This notion is reinforced by research
and meta-analytical reviews that have
proven that both prepubertal children
and adolescents can achieve training-
induced improvements in muscular
strength (12,13,40,42,48).
The YPD model shows that the devel-
opment of muscular strength should be
a priority at all stages of development
for both males and females (Figures 1
and 2). This notion is based on
previous research that has revealed
close associations between muscular
strength and running speed (114),
muscular power (104,116), change of
direction speed (78), plyometric ability
(71), and endurance (53). Additionally,
it has been speculated that muscular
strength is indeed critical for successful
FMS development (12). Consequently,
it is reasonable to suggest that devel-
oping levels of muscular strength
should be a priority of any athlete
development program, as strength
would appear to transcend all other
fitness components. Although not all
these relationships have been validated
in pediatric populations, early research
has indicated that muscular strength
(in addition to stature) could account
for up to 70% of the variability in
a range of motor skills including
throwing, jumping, and sprinting in
7- to 12-year-old boys (106).
The development of muscular strength
should also be viewed as an integral
component of youth strength and
conditioning programs not only for
performance enhancement but also for
reducing the risk of sport-related
injuries (39). It has been reported that
high aerobic fitness and low levels of
muscle strength heighten the risk of
fracture in children participating in
exercise protocols (26), highlighting
the importance of strength within an
Figure 2. The YPD model for females. Font size refers to importance; light pink boxes refer to preadolescent periods of adaptation,
dark pink boxes refer to adolescent periods of adaptation. FMS = fundamental movement skills; MC = metabolic
conditioning; PHV = peak height velocity; SSS = sport-specific skills; YPD = youth physical development.
VOLUME 34 | NUMBER 3 | JUNE 2012
Youth Physical Development Model
athletic development program. It is
now accepted that the risk of sports-
related injuries in yout hs can be
reduced by regular ly engaging in an
appropriately designed strengt h
training program that is supervised
by appropriately qualified personnel
(42,73). In 2011, the National
Athl e t i c Trainer s ’ A s s oci a t i on sug-
gested that approximately 50 % of
overuse injuries within youth sports
could be preven table in part with
appropriate preparatory conditioning
(109). However, it must be stressed
that strength development sessions
should not simply be viewed as an
addition to a young athletes’ devel-
opment program but as a replacement
for another form of training (e.g.,
endurance tra ining or skill develop-
ment session).
The YPD model depicts that an
emphasis on training for hypertrophy
may begin around the ages of 14 years
in male and 12 years in female athletes.
As mentioned previously, these phases
of development will typically occur
after PHV, at a time where levels of
circulating testosterone and growth
hormone rapidly increase in accor-
dance with the adolescent growth
spurt (68,110). Increases in serum con-
centrations of testosterone, estradiol,
and progesterone have been directly
linked with the stimulation of protein
synthesizing pathways (45) and are
responsible for the pubertal growth
spurt and adaptations to muscle and
skeletal tissue (19). Although not
proven with direct evidence, it is
reasonable to assume that because of
a lack of circulating androgens, signif-
icant training-induced increases in
muscle size before adolescence would
appear limited. Consequently, within
the YPD model, it is suggested in terms
of resistance training that a focus
should be geared toward strength
development before adolescence, and
after the adolescent spurt, strength
training should be interspersed with
bouts of hypertrophy training to make
further gains in muscular strength and
overall performance.
The ability to generate high levels of
power is essential for sporting success
(119); however, power is omitted from
the current LTAD model (7). Vertical
jump height is an indirect measure of
muscular power, and owing to its
simplicity, most developmental litera-
ture has used the test modality to assess
pediatric lower limb muscular power
The YPD model shows that the key
period of power development starts at
the onset of adolescence and continues
throughout adulthood, largely because
of rapid improvements in muscle
power during adolescence being attrib-
uted to maturational influences (15).
However, although power develop-
ment is emphasized primarily after
the onset of puberty, the YPD model
does suggest that some training focus
should also be given to developing
power during the prepubertal
phase. This is in r esponse to
research that shows that both chil-
dren and adolescents can make
worthwhile training-induced impro-
vements in measures of muscular
power (25,41, 64,69,92,97,118). As is
the case with m uscular strength, the
research would therefore suggest
that muscular power is trainable
throughout childhood, although the
magnitude and rate of development
may differ before and after the onset
of puberty.
Currently, the LTAD model advocates
that windows of opportunity for speed
development are entirely age related
(7). According to the model, any
training effects will therefore result
from neural adaptations, which have
previously been highlighted as signifi-
cant factors in speed gains (21).
However, alternative research has
indicated that speed development in
young athletes might also be influenced
by maturation (94), which suggests that
as is the case with many fitness
components, speed is indeed trainable
throughout childhood and adolescence.
Interestingly, the review of Rumpf et al.
(94) revealed that prepubescents
benefited most from training requiring
high levels of neural activation (plyo-
metrics and sprint training), whereas
adolescents responded more favorably
to training modes that targeted both
neural and structural development
(strength and plyometrics). This might
support the concept of windows when
different training adaptations predomi-
nate reflecting natural development;
however, trainability per se remains
throughout childhood. From a practical
perspective, this would suggest that
prepubescent children should focus
their speed development around plyo-
metrics, technical competency, and
sprint work to develop existing physical
qualities, whereas adolescents should
focus more on strength training, plyo-
metrics, and sprint training, to maximize
overall speed gains.
Agility is arguably one of the most
underresearched fitness components
within the pediatric literature, despite
the acknowledgment that a high
degree of agility is required for optimal
performance in the majority of sports
(56). Furthermore, a window of oppor-
tunity is not present within the current
LTAD model (7). Consequently, it is
difficult to determine whether age,
maturation, or both are determinants
of agility performance. There is a lack
of research that identifies appropriate
time frames to target agility-specific
training. Therefore, the YPD model
makes inferences in relation to the
development of the subcomponents of
agility, as defined previously (99,120):
change of direction speed (inclusive of
technique, straight sprinting speed,
lower limb strength, and anthropom-
etry) and cognitive function (perceptual
and decision-making processes).
Change of direction speed. When
examining the literature surrounding
these components, the YPD model
suggests that agility should be targeted
during both prepubescence and ado-
lescence. As lower limb strength
and straight running speed are compo-
nents of agility (120), it is logical to
look to develop agility and reinforce
Strength and Conditioning Journal |
coordination and movement pattern
accuracy during the early years. The
prepubertal years have already been
shown to represent an opportunity for
children to enhance strength (12,48)
and speed (94), resulting from
enhanced neural contribution to rate
of force development (110). Once
a child reaches adolescence, they will
typically experience further gains in
strength through continued neural
maturation and also significant in-
creases in lean muscle mass, owing to
increased serum androgen concentra-
tions (110). It is reasonable to suggest
that adolescence will therefore serve as
an opportune time to further develop
agility, as peak force and peak rate
of force development are likely to
increase because of the adaptation in
muscle structure. Prepubescence has
also been identified as a period that
sees children undergo rapid develop-
ments in the neuromuscular system
(21), with the rates of brain maturation
peaking between 6 and 8 and 10 and
12 years (90). Naturally, owing to the
neural plasticity associated with pre-
pubescence, this would seem an ideal
opportunity to develop motor control
programs inclusive of basic change
of direction techniques in the first
instance and then progressing to more
sport-specific agility movements as the
child approaches adolescence.
Cognitive function. According to
Sheppard and Young (99), a number
of perceptual variables influence agility.
Specifically, the authors state that
visual scanning, knowledge of situa-
tions, pattern recognition, and antici-
patory qualities influence individual
agility performance (99). Minimal lit-
erature exists examining the influence of
growth and maturation on these com-
ponents and their subsequent effects
on agility performance. Outside sport-
ing situations, research suggests that
cognitive capacities increase during
late childhood and adolescence and
that throughout these phases of
development, repeated exposure to
a given stimulus will result in faster
response times because of an apparent
strengthening of existing synaptic path-
ways (24). Whether these theories
translate to actual sporting situations,
in which athletes will need to react
rapidly to fluctuating stimuli (e.g. body
position, bounce of ball, opposition
movement), remains to be seen.
It is expected that the locomotive
vocabulary developed during the pre-
pubertal phase will continuously be
enhanced as the child progresses
through adolescence and into adult-
hood, through an increase in experiential
learning opportunities within sports-
specific environments. Given the lack
of existing developmental literature, it is
suggested that the training focus of
agility should be made more challenging
as the individual progresses thro ugh
childhood and into adulthoo d, with
the use of more open and unplanned
training methods to continually overload
the training stimulus. Additionally, with
an incr ease in traini ng demands within
an overall athletic schedule, it is expected
that agility development (and mainte-
nance) will be garnered from specific
sports skill-based sessions, where move-
ment demands replicate the exact loco-
motive demands of the sport.
As per speed development, a caveat
should be noted for agility development
during adolescence, as children learn to
move with longer limbs. The rapid
gains in limb length during the adoles-
cent growth spurt can lead to decre-
ments in motor control performance,
a concept commonly referred to as
‘‘adolescent awkwardness’’ (87). During
this stage of development, researchers
have suggested that many of the pre-
viously acquired movement patterns
will need to be reperfected (37).
Through regular monitoring of growth
rates, periods of adolescent awkward-
ness can potentially be identified and
strength and conditioning coaches
should be aware of the underlying
processes attributable to such disrup-
tions in motor control and adjust the
content of training sessions accordingly.
Despite highlighting ‘‘suppleness’’ as
one of the key components to develop
through training (7), the LTAD model
fails to suggest an appropriate window
of opportunity for its development.
The YPD model purports that at no
stage is mobility the main emphasis of
a training program during childhood or
adolescence. However, it should be
noted that as authors, we recommend
that mobility development and main-
tenance should be an essential part of
any athletic program to ensure athletes
are capable of reaching the requisite
ranges of motion required for their
Specifically, the YPD model proposes
that middle childhood (ages 5–11)
serves as the most important time
frame for an individual to incorporate
flexibility and mobility training. The
rationale for this selection is that it
incorporates a period that has pre-
viously been termed a critical period of
development for flexibility (67,96). Sex
differences are apparent within the
research, suggesting that boys show
a reduction in trunk forward flexibility
between 9 and 12 years (16), whereas
girls demonstrate accelerated improve-
ment beginning at 11 years of age (22).
It is therefore suggested that pre-
pubescence serves as an opportunity
to develop mobility, whereas main-
tenance of the acquired levels
should be the focus for adolescents
and adults.
Early research produced conflicting
results with respect to the trainability
of youths, with studies suggesting that
children who were circa-PHV pos-
sessed greater training responsiveness
(113) or, conversely, that large training
gains were possible for children who
were pre-PHV (93). It is suggested that
inconsistencies in research design have
been attributable to these confounding
results and that a lack of longitudinal
empirical evidence refutes the claims of
the existence of a window of opportu-
nity as defined in the LTAD model (44).
Regardless of the lack of evidence,
growth-related changes in central and
peripheral cardiovascular systems, neu-
romuscular function, and metabolic
VOLUME 34 | NUMBER 3 | JUNE 2012
Youth Physical Development Model
capacities are expected to influence
endurance and metabolic conditioning
development throughout childhood
(93). As physiological components are
continuingly developed throughout
childhood and adolescence, it is not sur-
prising that prepubertal, circumpuber-
tal, and postpubertal children have all
been reported as being able to make
worthwhile improvements in endur-
ance performance as indicated by
max responses (3).
The YPD model proposes that more
attention is given to endurance and
metabolic conditioning as the child
approaches adulthood, and at no stage,
it is seen as the main focus of an
individual’s training. Although this may
appear controversial, the rationale is
based on the assumption that an
individual will be exposed to sport-
specific endurance development while
participating in organized matches or
competitions and potentially within
a technical skill session of their given
sport. Additionally, remarkable levels of
endurance are not necessarily required
in the majority of sports, and endurance
appears to remain trainable in adult-
hood. Within the education sector,
cardiovascular endurance is inadver-
tently the most commonly developed
fitness component, as asking a child to
perform some form of submaximal
locomotion would appear safer to
teachers than asking them to participate
in some form of resistance training. This
is especially the case within the primary
school setting in the United Kingdom,
where not only have strength levels in
children diminished in the last decade
(31) but also it is recognized that
teachers are inappropriately prepared
through their teacher training to teach
physical education and that statutory
requirements for physical education are
routinely not achieved (59).
The YPD model is presented for both
males (Figure 1) and females (Figure 2)
displaying what would be classified as
an average maturing child (i.e., not an
early or late maturer). However,
strength and conditioning coaches will
habitually come into contact with
athletes of varying stages of matura-
tion, age, sex, and training history.
Although previous models have
alluded to these variables (7), it is not
apparent that the impact of the
individual variables on training pre-
scription has been addressed. Conse-
quently, the following section will
examine how the YPD model should
be manipulated when considering sex-
dependent factors, timing and rates of
maturation, and the training history
associated with different athletes.
Despite more boys engaging in youth
sports than girls, there has been an
increase in the overall number of
children and adolescents actively par-
ticipating in organized youth sports
over the past decade (77). With
participation numbers increasing, it is
imperative that any strength and
conditioning coach is aware of the
physiological and maturational differ-
ences that exist between males and
females and design-specific programs
During the prepubertal years, boys and
girls will follow similar rates of devel-
opment in growth and maturation, and
despite consistent sex differences,
strength, speed, power, endurance,
and coordination will develop at sim-
ilar rates for both sexes throughout
childhood (14). Consequently, from
a training perspective, both boys and
girls can follow similar training pro-
grams during the prepubertal years.
The YPD model advocates a prepuber-
tal focus of training for both boys and
girls that centers on FMS, strength
speed, and agility development.
The prepubertal years are a period
where children will experience rapid
gains in bone mass because of model-
ing and remodeling (9). Exposure to
appropriately designed weight-bearing
exercise of moderate- to high-load
intensity (with appropriate technical
competency) is an osteogenic stimulus
(60,61,111,115). Such training can result
in large increases in bone mass and
density (5,10,17,46,117), and research
has suggested that this adaptive res-
ponse is most sensitive during the
prepubertal years (8). Due to women
possessing a greater risk of osteoporosis
in later life (58) and that strength
training has previously been deemed
to offer the potential of reducing
osteoporotic fractures in older women
(79), the importance of strength training
for women at all stages of development
should not be underestimated.
Upon the onset of the adolescent
growth spurt, clear maturational differ-
ences are apparent for nearly all
components of fitness, with men
making greater improvements in most
physical qualities, with the exception of
flexibility (14,68). Typically, the onset
of the adolescent growth spurt occurs
around 2 years earlier in girls (about
10 years of age) than in boys (approx-
imately 12 years of age) (14), and in the
majority of instances, girls experience
PHV at an earlier age than boys
(12 years versus 14 years) (15). Despite
an earlier attainment of PHV in girls,
the magnitude of the growth spurt is
greater in boys (15).
During the adolescen t spurt, female
athletes will un dergo sex-specific
physiological processes that may
affect performance: increased fat
mass, differential rates of develop-
ment of neuromuscular strength, and
height and weight; commencement of
menstrual cycle, increased joint laxity,
increased kne e valgus angle; and
increased reliance on quadrice ps-
dominant landing strategies, all of
which have been ass ociated with
an increased risk of noncontact
anterior cruciate ligament injury
(2,43,51,52,72,75,86 ,89).
Consequently, the YP D model sug-
gests that training strategies designed
to reduce the risk of noncontact
anterior cruciate ligament injuries,
such as plyometrics, core strength-
ening, strength training, and balance
and perturbation training (74),
should be implemented within the
strength and conditioning program
Strength and Conditioning Journal |
of female athletes and maintained
into adulthood.
Because of the highly in dividual ti ming
of maturation, it is imperative that an y
LTAD model contains a degree of
flexibility (65). An early maturing child
has previously been defined as a girl
or boy who sta rts their ado lescent
growth spurt approximately 1.5 o r
2 years earlier than a late maturing
child (47).
Although research has indicated
that eventual adult height is not
affected by early or late maturation
(49), strength and conditioning
coaches must appreciate that an early
or late maturing child will need to
be treated somewhat differently than
an ‘‘average’’ maturing child, when
prescribing long-term athletic develop-
ment programs. For example, if a child
is routinely monitored for stature and
body mass every 3–6 months through-
out childhood, growth rates, percent-
age of adult height, and predictions of
age from PHV can be calculated (70).
Using these measurements, the matu-
rational status of a child can be
approximated, thus providing a more r-
obust estimate of their biological age.
In relation to the YP D model, if
maturer, then the compone nts of
the model will need to be moved to
the left, thus enabling the child to
commence more advanced training
techniques at an earlier chronologic
age. In contrast, a strength and
conditioning coach must allow the
components of the YP D model to
be moved to the right for a child
who is deemed a late maturer, thereby
introducing them to more adva nced
training at a later chronologic age,
when they are physiologically ready
to c ope with the increased training
stimulus. In either of these instances,
although training prescription will
vary according to chronological age,
it should allow grea ter consistency
and more accuracy in terms of the
child’s biological age.
Irrespective of chronological or biolog-
ical age, a strength and conditionin g
coach must give thought to the training
age of any athlete that they start
working with. Training age can be
defined as the number of years an
athlete has been participating in formal-
ized training and is an important factor
to consider when designing long-term
athletic development programs. Such an
approach is particularly pertinent when
begins to work with an athlete who is
approaching adulthood that has missed
the initial stages of the YPD model.
In such an instance, the athletes should
begin with early development of FMS
and muscular strength before embark-
ing on the training content that is
commensurate with their chronologi-
cal age. Conversely, should a strength
and conditioning coach begin working
with an early maturing 10-year-old boy
who can display exceptional strength,
speed, and power while maintaining
the requisite technical competency,
then they should not be restricted to
the introductory training methods
more akin to his chronological age.
This concept has previously been
discussed in relation to both plyomet-
ric (63) and weightlifting (65) devel-
opment models.
Well-being has been defined as a pos-
itive and sustainable state that allows
individuals, groups, or nations to thrive
and flourish (54). The philosophy of
the YPD model is that it permits
individualization, is athlete centered,
and promotes the development of the
child over performance outcomes. This
may sacrifice short-term performance
success but should maximize the
opportunity to foster a sense of well-
being and provide long-term gains.
This philosophy will help the child to
appreciate the benefits of training and
develop intrinsic motivation for par-
ticipating in training, which is a strong
predictor of well-being (95) and is
associated with positive behaviors
(112). Additionally, provided the coach
can deliver the content of the model in
a positive manner the child should
recognize the gains they are achieving
(e.g., technical, physical, developmen-
tal), leading to increased perceived
competence, which is a primary
determinant of a sense of well-being
in child athletes (91). This will increase
the likelihood of the child being able
to persist in the face of adversity and
to sustain continued interest in sport
The YPD model advocates the devel-
opment of FMS from a young age,
which are associated with physical and
psychologic health benefits in children
(66). Furthermore, the progression
provided throughout the YPD model
will enable the children to experience
continued mastery of new tasks
throughout their developmental years.
Task mastery is associated with incre-
ased enjoyment, perceived competence,
satisfaction, and beliefs that effort causes
success (81,101,107). Such positive
experiences should also provide valu-
able and highly transferable life skills
(33). The continued and overlapping
development of a number of fitness
components in the YPD model should
also provide the strength and condi-
tioning coach with the ability to
develop training programs containing
a high degree of variation, something
that has been suggested to be important
in maintaining the interest of and
promoting the well-being of child
athletes (85).
It is important to realize that the
success of any long-term development
program will be dependent largely on
the level of education and quality of
instruction received by the athlete from
the responsible coach (73). Within the
literature, cases of training-induced
injury in children and adolescents are
reported only in instances where
a young athlete has been exposed to
excessive, unfamiliar, and poorly pre-
scribed training, which in both cases
have led to exertional rhabdomyolysis
VOLUME 34 | NUMBER 3 | JUNE 2012
Youth Physical Development Model
and hospitalization (27,28). Research
suggests that outside these isolated
cases, most incidences of resistance
training-related injuries tend to be
accidental in nature, with the number
of accidental injuries decreasing with age
(76). However, to minimize the chances
of such isolated ins tance s occurring, it is
imperative that those coaches who
actively coach young athletes possess
the appropriate credentials.
First, a coach must hold a relevant
strength and conditioning qualification
(e.g., Certified Strength and Condition-
ing Specialist in the United States or
Accredited Strength and Conditioning
Coach in the United Kingdom). Sec-
ond, a coach must have a sound un-
derpinning knowledge of pediatric
exercise science, ideally at an under-
graduate or postgraduate level. Finally,
a coach should have a strong peda-
gogical background to ensure they
have an appreciation of the different
styles of communication and interac-
tion that they will need to adopt with
athletes, who might range from early
prepubescent to late adolescent. Satis-
faction of these criteria will hopefully
ensure that young athlete development
models are delivered in a safe and
effective manner, underpinned
by appropriate individual program
design (inclusive of exercise selection
and progressions, volume loads, rest,
and recovery), realistic goal setting, and
a coaching philosophy that is tailored
toward the holistic development of the
young athlete.
The present article has provided a sound
rationale for the YPD model. This
approach to the development of young
athletes appears to be more realistic in
terms of acknowledging that most
fitness components are trainable
throughout childhood. Central to the
YPD model is that during prepubes-
cence, strength, FMS, speed, and agility
should be the main physical qualities
targeted and that adaptive responses to
the appropriate training methods will be
neural in nature. Once the child reaches
adolescence, additional components
(SSS, power, and hypertrophy) become
more important owing to the increased
androgenic internal environment asso-
ciated with this stage of development.
The need for individualization of the
model should not be underestimated
when dealing with athletes of different
sex, maturity status, and training history.
Crucially, appropriately qualified per-
sonnel should always be responsible for
the imp lementation of the YPD model,
to ensure the holistic development of
children and adolescents.
Rhodri S. Lloyd
is the program
director for the
Sport Strength and
degrees at the
University of
Jon L. Oliver
is a lecturer in
Sport and Exercise
Physiology at
Cardiff Metropoli-
tan University.
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VOLUME 34 | NUMBER 3 | JUNE 2012
Youth Physical Development Model
... Once in secondary education (i.e., key stages three and four) the focus shifts towards teaching pupils' techniques through playing competitive sports and focusing on performance during PE lessons [28]. Thus, there appears to be alignment between the PE curriculum and long-term athletic development models (e.g., youth physical development model [30]), which recommend a similar approach of progressing motor competence development from fundamental movement skills towards sports specific skills as youth physically and psychosocially mature. However, S&C coaches do not have a set curriculum, only recommendations from long-term athletic development models, meaning they have more freedom and subjectiveness with what they deliver within their youth programmes. ...
... Therefore, understanding and comparing perceptions between coaches and teachers may highlight the need for coach/teacher education and could facilitate collaboration and curriculum reflection to enhance motor competence development for all youths. Additionally, results from Burton et al. [27] failed to account for how S&C coaches' perceptions may differ according to stage of maturity, which has been highlighted as a critical feature of long-term athletic development [2,26,30]. Therefore, it is necessary to explore how perceptions of coaches and teachers differ between stages of maturity (i.e., childhood, adolescent pre-peak height velocity [PHV], adolescent circa-PHV, adolescent post-PHV). ...
... Within the questionnaire, participants reported their perceptions of motor competence across the stages of maturity. The stages of maturity were described in the questionnaire based on the thresholds stated in the Youth Physical Development model for males and females [30] because the model presents stages of maturity for males and females, along with chronological ages ranges where each stage typically occurs. This factor therefore enabled participants who may be unfamiliar with the maturity status concept (e.g., PE teachers as their curriculum aligns towards chronological rather than biological age) to provide perceptions for each stage of maturity. ...
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Physical education (PE) teachers and strength and conditioning (S&C) coaches are well placed to develop motor competence within youth populations. However, both groups’ perceptions of important motor competencies are relatively unknown, especially when considering stage of maturity. Therefore, this study aimed to 1) present PE teachers and S&C coaches’ perceptions of motor competence importance according to stage of maturity; 2) compare perceptions of motor competence between stages of maturity, and between PE teachers and S&C coaches; and 3) explore factors that influence PE teachers and S&C coaches’ perceptions of motor competence importance. Via a mixed-method questionnaire, 47 PE teachers (professional experience = 10.3±6.6 years) and 48 S&C coaches (professional experience = 8.6±4.8 years) rated the importance of developing 21 motor competencies across four stages of maturity (childhood, pre-peak height velocity [PHV], circa-PHV, and post-PHV) using a Likert-scale (1 = not important, 5 = very important). Participants also provided open-ended explanations for their perceptions. Frequency analysis indicated that participants rated a broad range of competencies important, with S&C coaches rating more competencies important than PE teachers across all stages of maturity. Mixed-model analysis highlighted several differences in motor competence importance when comparing perceptions between participant groups, and between stages of maturity for PE teachers and S&C coaches. For example, S&C coaches rated strength-based motor competencies less important during childhood ( d = -1.83 to -0.43), while PE teachers rated them less important during childhood ( d = -2.22 to -0.42) and pre-PHV ( d = -1.70 to -0.51) compared to other stages of maturity. Codebook thematic analysis showed several factors that influenced participant’s perceptions of motor competence importance (e.g., participants understanding of themselves). The findings suggest that multiple environments may be required to adequately facilitate motor competence development amongst youth. Coach education should target misunderstandings around the risks of strength-based activity during early stages of maturity and the benefits of developing strength-based motor competencies across youth populations.
... In contrast, linear speed performance did not significantly differ between young male vs. female runners of different age categories (U8-U16 years) (15). Moreover, in addition to the empirical findings, the youth physical development model introduced by Lloyd and Oliver (16) suggested that fitness components are not equally important throughout the stages of long-term athlete development. While muscle strength should be a priority at all stages for males and females, attention to endurance and metabolic conditioning is given as the child approaches adulthood, and at no stage, it is seen as the main focus of an individual's training (16). ...
... Moreover, in addition to the empirical findings, the youth physical development model introduced by Lloyd and Oliver (16) suggested that fitness components are not equally important throughout the stages of long-term athlete development. While muscle strength should be a priority at all stages for males and females, attention to endurance and metabolic conditioning is given as the child approaches adulthood, and at no stage, it is seen as the main focus of an individual's training (16). Consequently, measures of anthropometry, physical fitness, and sport-specific performance and the respective inter-item correlation may specifically depend on age and/or sex potentially affecting the accuracy and structure of statistical models. ...
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Introduction: Anthropometric and physical fitness data can predict sport-specific performance (e.g., canoe sprint race time) in young athletes. Of note, inter-item correlations (i.e., multicollinearity) may exist between tests assessing similar physical qualities. However, multicollinearity among tests may change across age and/or sex due to age-/sex-specific non-linear development of test performances. Therefore, the present study aimed at analyzing inter-item correlations between anthropometric, physical fitness, and sport-specific performance data as a function of age and sex in young canoe sprint athletes. Methods: Anthropometric, physical fitness, and sport-specific performance data of 618 male and 297 female young canoe sprint athletes (discipline: male/female kayak, male canoe) were recorded during a national talent identification program between 1992 and 2019. For each discipline, a correlation matrix (i.e., network analysis) was calculated for age category (U13, U14, U15, U16) and sex including anthropometrics (e.g., standing body height, body mass), physical fitness (e.g., cardiorespiratory endurance, muscle power), and sport-specific performance (i.e., 250 and 2,000-m on-water canoe sprint time). Network plots were used to explore the correlation patterns by visual inspection. Further, trimmed means (μtrimmed) of inter-item Pearson's correlations coefficients were calculated for each discipline, age category, and sex. Effects of age and sex were analyzed using one-way ANOVAs. Results: Visual inspection revealed consistent associations among anthropometric measures across age categories, irrespective of sex. Further, associations between physical fitness and sport-specific performance were lower with increasing age, particularly in males. In this sense, statistically significant differences for μtrimmed were observed in male canoeists (p < 0.01, ξ = 0.36) and male kayakers (p < 0.01, ξ = 0.38) with lower μtrimmed in older compared with younger athletes (i.e., ≥U15). For female kayakers, no statistically significant effect of age on μtrimmed was observed (p = 0.34, ξ = 0.14). Discussion: Our study revealed that inter-item correlation patterns (i.e., multicollinearity) of anthropometric, physical fitness, and sport-specific performance measures were lower in older (U15, U16) versus younger (U13, U14) male canoe sprint athletes but not in females. Thus, age and sex should be considered to identify predictors for sport-specific performance and design effective testing batteries for talent identification programs in canoe sprint athletes.
... 32 These findings indicate that while coaches value strength and conditioning programmes for different reasons, the primary benefits will likely align with broader principles of longterm athletic development frameworks. 33 Coach and player education should continue to highlight that strength and conditioning programmes have the dual benefit of improving performance and reducing the risk of injury. In practical terms, strength and conditioning programmes should look to incorporate training modes that target neuromuscular qualities (e.g. ...
... Research has shown that prepubescence is an important developmental stage to introduce children to neuromuscular training due to their heightened neural plasticity. 33 Therefore, children should begin participating in some form of resistance training once it is deemed that they are mature enough to respond to coaching instruction and to handle the demands of training. 31 If young golfers are only exposed to strength and conditioning from 14 to 15 years of age onwards, they will arguably be missing out on a crucial stage of their long-term athletic development journey. ...
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Golfers who want to improve their technical proficiency will undoubtedly hire a swing coach who may also influence and give advice on how the golfer can improve outside of technical enhancement (i.e. strength and conditioning, warm-ups, cool-downs etc.). With research examining the effects of strength and conditioning on youth golfers beginning to materialise, it is important to ascertain golf coaches' perceptions of strength and conditioning, warm-ups and cool-downs and how they are utilised with youth golfers. Fifty Professional Golfers' Association Professionals and Assistant Professionals completed an online questionnaire on their perceptions of, and approaches to, strength and conditioning, warm-up and cool-down activities for youth golfers. Data indicated that 84% and 80% of coaches perceived strength and conditioning could enhance golf swing performance and reduce the risk of injury, respectively. Although all coaches agreed golfers aged 18 years and under can take part in strength and conditioning activities, there was no consensus on when a golfer should start strength and conditioning activities, with most coaches unaware of the existing guidelines surrounding youth resistance training. Warm-ups are perceived by coaches to be beneficial for youth golfers with > 75% of coaches stating their players completed a warm-up, however, the modes of exercise coaches deemed suitable for a warm-up were varied. Cool-downs were deemed beneficial for aiding recovery post-round, yet over half of coaches selected their players did not habitually complete one. Findings from the questionnaire highlight that although perceptions towards strength and conditioning, warm-ups and cool-downs are positive, educational solutions to disseminate the underlying contemporary guidelines and practical applications to coaches and players are required.
... Developing strength and power is recommended in LTAD models 14 and is supported by NGBs. [15][16][17] When comparing the chronological age academy players start a formal S&C program, the current study demonstrated that players in SA start later than those in the UK (Figure 1), which may impact their ability to fulfill their physical potential. ...
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Differences exist between top-tier soccer leagues (e.g. anthropometry and match demands), which may influence strength and conditioning (S&C) practice. Thus, the aim of this study was to investigate whether current S&C practice in men's and women's (first team and academy) squads differed between global regions. A total of 170 participants, involved in the delivery of S&C support at their soccer club (based on South America (SA), the USA, the UK, or other European countries (EUR)), completed a survey examining their S&C methods. The survey comprised six sections: (i) academic qualifications and S&C coaching experience; and their preferred methods for (ii) physical testing; (iii) strength and power development; (iv) plyometric training; (v) speed development; and (vi) periodization. Coaches in EUR conducted fewer formal S&C sessions, placed less importance on free-weight resistance training (RT), and performed less speed and plyometric training compared to coaches in other global regions (all p < 0.05). While coaches working with UK squads devoted more time to physical development than those in EUR, they regarded bodyweight training as the most important RT modality in comparison to USA and SA, who prioritized free-weight RT. Finally, SA academy players are introduced to formal S&C later (∼14 years old) than those in the UK (∼12 years old, p = 0.002). However, it is reasonable to suggest that the S&C practice of coaches in the USA and SA align better with scientific guidelines for strength and power development in soccer, with emphasis on free-weight RT alongside regular sprint and plyometric training, compared to coaches in the UK and EUR.
... Previous study suggested that most physical qualities are trainable throughout maturation [18]. However, an incorrect exercise technique or poor supervision increases the resistance training (RT) injury risk of adolescent athletes [19]. ...
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Unlabelled: This study investigated the effects of handheld-load-specific jump training on standing broad jump (SBJ) performance in youth athletes and the biomechanics changes involved. Methods: Fifteen male athletes (mean age, body weight, height, and body mass index were 14.7 ± 0.9 years, 59.3 ± 8.0 kg, 1.73 ± 0.07 m, 19.8 ± 2, respectively) underwent 15 SBJ training sessions over 8 weeks. The data were collected over three phases: before training, after training, and after training with 4 kg loading. Ten infrared high-speed motion-capture cameras and two force platforms, whose sampling rates were 250 and 1000 Hz, respectively, were used to record the kinematic and kinetic data. Visual three-dimensional software was used for the data analyses. Results: Jump performance and all biomechanics variables, including joint and takeoff velocities, ground reaction force, takeoff impulse, and mechanical outputs, improved after training. Conclusions: SBJ training under handheld loading resulted in considerable acute improvements as well as training transfer after 8 weeks. Moreover, explosive ability was effectively enhanced. The present findings serve as a reference for SBJ assessment and jump-related training.
... In addition, the participating U15 but not U13 players were already engaged in some basic strength and power training, including two weekly sessions, which further explains better lower limbs performance in the older compared with the younger age group (Table 4). Thus, between-group differences in measures of strength and power cannot only be related to developmental factors such as the growth spurt [56], but also to the positive effects of additional strength and conditioning exercises. ...
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Background The aim of this study was to analyze the shoulder functional profile (rotation range of motion [ROM] and strength), upper and lower body performance, and throwing speed of U13 versus U15 male handball players, and to establish the relationship between these measures of physical fitness and throwing speed. Methods One-hundred and nineteen young male handball players (under (U)-13 (U13) [n = 85]) and U15 [n = 34]) volunteered to participate in this study. The participating athletes had a mean background of sytematic handball training of 5.5 ± 2.8 years and they exercised on average 540 ± 10.1 min per week including sport-specific team handball training and strength and conditioning programs. Players were tested for passive shoulder range-of-motion (ROM) for both internal (IR) and external rotation (ER) and isometric strength (i.e., IR and ER) of the dominant/non-dominant shoulders, overhead medicine ball throw (OMB), hip isometric abductor (ABD) and adductor (ADD) strength, hip ROM, jumps (countermovement jump [CMJ] and triple leg-hop [3H] for distance), linear sprint test, modified 505 change-of-direction (COD) test and handball throwing speed (7 m [HT7] and 9 m [HT9]). Results U15 players outperformed U13 in upper (i.e., HT7 and HT9 speed, OMB, absolute IR and ER strength of the dominant and non-dominant sides; Cohen’s d: 0.76–2.13) and lower body (i.e., CMJ, 3H, 20-m sprint and COD, hip ABD and ADD; d: 0.70–2.33) performance measures. Regarding shoulder ROM outcomes, a lower IR ROM was found of the dominant side in the U15 group compared to the U13 and a higher ER ROM on both sides in U15 (d: 0.76–1.04). It seems that primarily anthropometric characteristics (i.e., body height, body mass) and upper body strength/power (OMB distance) are the most important factors that explain the throw speed variance in male handball players, particularly in U13. Conclusions Findings from this study imply that regular performance monitoring is important for performance development and for minimizing injury risk of the shoulder in both age categories of young male handball players. Besides measures of physical fitness, anthropometric data should be recorded because handball throwing performance is related to these measures.
... The variation of maturation status (i.e., early, on-time, and late) between players within a single chronological age group can lead to up to 5-years difference in biological age [41]. The trainability and performance of physical competencies are closely aligned with maturity status [42]. Male players who experience their adolescent growth spurt mature earlier than their peers are invariably taller and heavier from late childhood and possess greater absolute and relative lean mass [43][44][45]. ...
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The talent development processes in youth football are both complex and multidimensional. The purpose of this two-fold study was to apply a multidisciplinary, machine learning approach to examine: (a) the developmental characteristics of under-9 to under-16 academy players (n = 98; Study 1), and (b) the characteristics of selected and deselected under-18 academy players (n = 18; Study 2). A combined total of 53 factors cumulated from eight data collection methods across two seasons were analysed. A cross-validated Lasso regression was implemented, using the glmnet package in R, to analyse the factors that contributed to: (a) player review ratings (Study 1), and (b) achieving a professional contract (Study 2). Results showed non-zero coefficients for improvement in subjective performance in 15 out of the 53 analysed features, with key findings revealing advanced percentage of predicted adult height (0.196), greater lob pass (0.160) and average dribble completion percentage (0.124), more total match-play hours (0.145), and an older relative age (BQ1 vs. BQ2: −0.133; BQ1 vs. BQ4: −0.060) were the most important features that contributed towards player review ratings. Moreover, PCDEQ Factor 3 and an ability to organise and engage in quality practice (PCDEQ Factor 4) were important contributing factors towards achieving a professional contract. Overall, it appears the key factors associated with positive developmental outcomes are not always technical and tactical in nature, where coaches often have their expertise. Indeed, the relative importance of these factors is likely to change over time, and with age, although psychological attributes appear to be key to reaching potential across the academy journey. The methodological techniques used here also serve as an impetus for researchers to adopt a machine learning approach when analysing multidimensional databases.
... It is highly recommended that children should participate in multiple sports at an early age (6-12) in order to develop a range of foundational skills (Côté 1999). Even throughout a participant's adolescence, coaches should be encouraged to support the maintenance of FMS as the focus on sport-specific skills increases (Lloyd and Oliver 2012). ...
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El propósito de esta relatoría es presentar una sistematización del material bibliográfico abordado por el Grupo de Estudios e Investigaciones en Rugby (GEIR) durante el período julio 2021-julio 2022 con el objetivo de ampliar la mirada en torno al proceso formativo que deben transitar los entrenadores y las entrenadoras de rugby. La selección de los textos abordados durante los meses de trabajo estuvo orientada a proporcionar a los/as entrenadores/as diversas herramientas que les permitan comprender las necesidades de sus deportistas, tomar mejores decisiones y emplear estrategias que resulten más eficaces a través de las cuales sea posible mejorar cada área de actuación. Anclado en un paradigma cualitativo a través del cual fue posible llevar adelante un análisis interpretativo de las lecturas abordadas, la interdisciplinariedad del Grupo de Estudios permitió avanzar en una lectura reflexiva que puso en diálogo aspectos teóricos y prácticos en relación a la formación de los/as entrenadores/as de rugby. Cabe mencionar que la siguiente relatoría fue realizada a modo de sistematización del trabajo realizado por el GEIR durante su primer año, el cual tuvo como único objetivo la revisión de diversos materiales bibliográficos para, en una segunda etapa de trabajo, proceder a la producción de artículos académicos.
Muscle mass and strength are subjected to several regulations. We found endocrine signals such as growth hormone, insulin-like growth factor 1, testosterone, thyroid hormones, and glucocorticoids among them. Neural inputs also influence muscle development, modulating mass and strength. Among the external stimuli that modulate these muscular features is physical training such as resistance and endurance training. Specifically, resistance training can mediate an increase in muscle mass by hypertrophy in adults, but the effects in children and adolescents are full of myths for most of the population. However, the evidence shows that the impact of resistance training on children and adolescents is clear and provides a wide range of benefits. However, qualified professionals must be available since exercise prescription and subsequent supervision must follow this population’s abilities, needs, and interests.
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Objectives To determine (1) correlations between isokinetic lower extremity strength and functional performance and (2) correlations among different modes of isokinetic testing. Design and Setting A correlational design with 6 measures. A series of strength, power, and agility tests was performed at a hospital-based outpatient physical therapy clinic. Participants A volunteer sample of 29 male and 31 female, college-age subjects participated. Measurements All subjects were tested in the following isokinetic tests: reciprocal leg press, single-leg squat, and knee extension. Performance tests included single-leg hop and vertical jump and a speed/agility test. Results Analysis showed isokinetic knee extension, leg press, and single-leg squat strength significantly correlated to all functional tests. There were significant correlations among the 3 different isokinetic strength measures, as well. Conclusions These results suggest a significant relationship between lower extremity open and closed chain isokinetic strength and functional performance testing.
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Annual age-grouping is a common organizational strategy in sport. However, such a strategy appears to promote relative age effects (RAEs). RAEs refer both to the immediate participation and long-term attainment constraints in sport, occurring as a result of chronological age and associated physical (e.g. height) differences as well as selection practices in annual age-grouped cohorts. This article represents the first meta-analytical review of RAEs, aimed to collectively determine (i) the overall prevalence and strength of RAEs across and within sports, and (ii) identify moderator variables. A total of 38 studies, spanning 1984–2007, containing 253 independent samples across 14 sports and 16 countries were re-examined and included in a single analysis using odds ratios and random effects procedures for combining study estimates. Overall results identified consistent prevalence of RAEs, but with small effect sizes. Effect size increased linearly with relative age differences. Follow-up analyses identified age category, skill level and sport context as moderators of RAE magnitude. Sports context involving adolescent (aged 15–18 years) males, at the representative (i.e. regional and national) level in highly popular sports appear most at risk to RAE inequalities. Researchers need to understand the mechanisms by which RAEs magnify and subside, as well as confirm whether RAEs exist in female and more culturally diverse contexts. To reduce and eliminate this social inequality from influencing athletes’ experiences, especially within developmental periods, direct policy, organizational and practitioner intervention is required.
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The purpose of this study was to investigate the effects of 9 months of plyometric jump training on bone mineral content (BMC), lower extremity performance, and static balance in adolescent girls (aged 14.6 +/- 0.5 yr; 22.7 +/- 14.0 months past menarche). Exercisers (N = 25) trained 30-45 min, three times per week, performing various exercises using weighted vests (squats, lunges, calf raises) and plyometrics (hopping, jumping, bounding, and box depth jumps). The program was designed to load the lower extremities. Controls (N = 28), matched to exercisers for age and months past menarche, maintained their usual activities. The following were assessed at baseline and 9 months: BMC, strength by isokinetic dynamometry, power (Wingate), and static balance. Repeated measures ANOVA revealed no significant differences between groups for BMC, nor were the changes in anthropometric or performance variables, analyzed by MANOVA, significant. In follow-up analyses, t-tests for independent samples revealed that both groups experienced a significant (P < 0.01) increase in percent change in bone mass compared to zero, for the whole body (mean: 3.7% exercisers, 3.6% controls), femoral neck (4.5% vs 2.4%), lumbar spine (L2-4) (6.6% vs 5.3%), and femoral shaft (3.4% vs 2.3%), but only the exercisers improved BMC of the greater trochanter (3.1% vs 1.9%). Furthermore, the exercise group significantly improved knee extensor strength (14.7% vs 7.3%) and medial/lateral balance (38.1% vs 9.5%), whereas the control group demonstrated no changes. The variety of lateral movement activities performed by the exercise group may have contributed to the differences observed between groups for greater trochanter bone mineral density (BMD), leg strength, and medial/lateral balance. The trends observed in bone mass between groups suggest that plyometric jump training continued over a longer period of time during adolescent growth may increase peak bone mass.
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Mastery-oriented motivational climates and achievement goal orientations have been associated with a range of salutary and clinically relevant outcomes in both educational and sport research. In view of this, an intervention was developed for youth sport coaches designed to promote a mastery motivational climate, and a field experiment was conducted to assess its effects on changes in athletes’ achievement goal orientations over the course of a sport season. The experimental group was comprised of 155 boys and girls, who played for 20 basketball coaches; 70 youngsters played for 17 control group coaches. The coach intervention resulted in higher Mastery-climate scores and lower Ego-climate scores compared with the control condition, and athletes who played for the trained coaches exhibited significant increases in Mastery goal orientation scores and significant decreases in Ego-orientation scores across the season, whereas control group participants did not. Practical and theoretical implications of the findings are discussed.
This study investigated a possible relationship between cardiorespiratory endurance and fundamental movement skill proficiency among adolescents. Locomotor (run and jump) and object-control (catch, throw, kick, and strike) skills and cardiorespiratory endurance, indirectly measured using the Multistage Fitness Test (MFT) or PACER, were assessed in 2,026 boys and girls in Grade 8 (mean age = 13.3 years) and Grade 10 (mean age = 15.3 years), who were part of a randomly selected sample who agreed to participate in the New South Wales Schools Fitness and Physical Activity Survey, 1997. Boys had higher levels of cardiorespiratory endurance and were more competent than girls on 5 out of 6 skills. Grade 10 students were better on all skills and were aerobically fitter than Grade 8 students. All six skills and a skills index were related to the number of laps completed on the MFF. The six skills explained 20% and 26% of the variance in the number of laps completed on the MFT for Grade 8 and Grade 10 girls, respectively, and 12% and 17% for Grade 8 and Grade 10 boys, respectively. This finding can be interpreted as evidence of a relationship between cardiorespiratory endurance and fundamental movement skills among adolescents. Further studies are recommended to determine if improved movement skills in adolescents can promote cardiorespiratory endurance.