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Position statement on youth resistance training:
the 2014 International Consensus
Rhodri S Lloyd,
1
Avery D Faigenbaum,
2
Michael H Stone,
3
Jon L Oliver,
1
Ian Jeffreys,
4
Jeremy A Moody,
1
Clive Brewer,
5
Kyle C Pierce,
6
Teri M McCambridge,
7
Rick Howard,
8
Lee Herrington,
9
Brian Hainline,
10
Lyle J Micheli,
11,12,13
Rod Jaques,
14
William J Kraemer,
15
Michael G McBride,
16
Thomas M Best,
17
Donald A Chu,
18,19
Brent A Alvar,
18
Gregory D Myer
7,13,20
For numbered affiliations see
end of article.
Correspondence to
Dr Gregory D Myer, Division of
Sports Medicine, Cincinnati
Children’s Hospital Medical
Center 3333 Burnet Ave,
MLC 10001, Cincinnati,
OH 45229, USA;
greg.myer@cchmc.org
Adapted from the position
statement of the UK Strength
and Conditioning Association
on youth resistance training
Endorsed by: American
Academy of Pediatrics (AAP);
American Alliance for Health,
Physical Education, Recreation
and Dance (AAHPERD);
American Medical Society for
Sports Medicine (AMSSM);
British Association of Sports
Rehabilitators and Trainers
(BASRaT); International
Federation of Sports Medicine
(FIMS); Faculty of Sport and
Exercise Medicine UK (FSEM);
North American Society for
Pediatric Exercise Medicine
(NASPEM); National Athletic
Trainers’Association (NATA);
Chief Medical Officer, National
Collegiate Athletic Associaiton
(NCAA); National Strength and
Conditioning Association
(NSCA)
Accepted 17 August 2013
To cite: Lloyd RS,
Faigenbaum AD, Stone MH,
et al.Br J Sports Med
Published Online First:
[please include Day Month
Year] doi:10.1136/bjsports-
2013-092952
ABSTRACT
The current manuscript has been adapted from the official
position statement of the UK Strength and Conditioning
Association on youth resistance training. It has
subsequently been reviewed and endorsed by leading
professional organisations within the fields of sports
medicine, exercise science and paediatrics. The authorship
team for this article was selected from the fields of
paediatric exercise science, paediatric medicine, physical
education, strength and conditioning and sports medicine.
OPERATIONAL DEFINITIONS
Prior to discussing the literature surrounding youth
resistance training, it is pertinent to define key ter-
minologies used throughout the manuscript.
▸Childhood represents the developmental period
of life from the end of infancy to the beginning
of adolescence. The term children refers to girls
and boys (generally up to the age of 11 and
13 years, respectively) who have not developed
secondary sex characteristics.
1
▸The term adolescence refers to a period of life
between childhood and adulthood. Although ado-
lescence is a more difficult period to define in
terms of chronological age due to differential mat-
uration rates,
2
girls 12–18 years and boys 14–
18 years are generally considered adolescents.
▸The terms youth and young athletes represent
global terms which include both children and
adolescents.
1
▸Growth is typically viewed as a quantifiable
change in body composition, the size of the
body as a whole or the size of specific regions of
the body.
3
▸Maturation refers to the highly variable timing
and tempo of progressive change within the
human body from childhood to adulthood, and
which, in addition to growth, influences overall
physical performance capabilities.
3
▸Training age refers to the number of years an
individual has been involved in a structured and
appropriately supervised training programme.
4
▸Resistance training refers to a specialised
method of conditioning whereby an individual
is working against a wide range of resistive loads
to enhance health, fitness and performance.
5
Forms of resistance training include the use of
body weight, weight machines, free weights
(barbells and dumbbells), elastic bands and
medicine balls.
▸Weightlifting is a sport that involves the per-
formance of the snatch and clean and jerk lifts
in competition.
6
Weightlifting training refers to
a variety of multijoint exercises including the
snatch, clean and jerk and modified variations of
these lifts, that are explosive but highly con-
trolled movements that require a high degree of
technical skill.
▸Qualified professional is a term used to repre-
sent those individuals who are trained and
aware of the unique physiological, physical and
psychosocial needs of children and adolescents,
and possess a relevant and recognised strength
and conditioning qualification (eg, the UK
Strength and Conditioning Association (UKSCA)
Accredited Strength and Conditioning Coach or
National Strength and Conditioning Association
(NSCA) Certified Strength and Conditioning
Specialist). Importantly, such individuals should
have a strong pedagogical background to ensure
that they are knowledgeable of the different
styles of communication and interaction that
will be needed to effectively teach or coach chil-
dren and adolescents.
45
Qualified professionals
should possess the knowledge and expertise to
plan, teach and progress age-related resistance
training programmes to youth of all ages and
abilities using various forms of resistance exer-
cises, and should be able to identify and modify
technical deficiencies when necessary. Qualified
professionals would also be expected to work
effectively and respectively with other health-
care practitioners (eg, physicians, physical thera-
pists, certified athletic trainers, registered
dieticians, physical education teachers, youth
coaches, paediatric exercise specialists and
researchers) to enhance the health and well-
being of all youth.
INTRODUCTION
Since seminal attempts to address concerns sur-
rounding prepubescent strength training,
7
the
concept of children and adolescents participating in
various forms of resistance training has been of
growing interest among researchers, clinicians and
practitioners. There is now a compelling body of
scientific evidence that supports regular participa-
tion in youth resistance training to reinforce posi-
tive health and fitness adaptations and sports
performance enhancement. There is even stronger
Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952 1
Consensus statement
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support for the use of resistance training in youth provided that
these programmes are supervised by qualified professionals and
consistent with the needs, goals and abilities of children and
adolescents.
58–13
Research has indicated that various forms of
resistance training can elicit significant performance improve-
ments in muscular strength,
14
power production,
515
running
velocity,
16
change-of-direction speed
17
and general motor per-
formance
12
in youth. From a health perspective, evidence indi-
cates that resistance training can make positive alterations in
overall body composition,
18
reduce body fat,
19 20
improve
insulin-sensitivity in adolescents who are overweight
21
and
enhance cardiac function in children who are obese.
22
Importantly, it has also been demonstrated that regular partici-
pation in an appropriately designed exercise programme inclu-
sive of resistance training, can enhance bone-mineral density
and improve skeletal health
23 24
and likely reduce sports-related
injury risk in young athletes.
25 26
This would appear to be an
important consideration given that approximately 3.5 million
sports-related injuries in youth require a medical visit each year
in the USA.
27
Comparable relative data from Europe found that
nearly 1.3 million cases of sports-related injuries reported in
2009 required hospitalisation for children under the age of
15 years.
28
Additionally, muscular strength and resistance train-
ing have been associated with positive psychological health and
well-being in children and adolescents.
29–33
The World Health Organization (WHO) and other public
health agencies now include resistance training as part of their
physical activity guidelines for children and adolescents.
34–36
However, recent evidence indicates that the muscular strength
levels of school-age youth are decreasing.
37–39
Progressive resist-
ance training under the supervision of qualified professionals
can offer a safe, effective and worthwhile method for reversing
this undesirable trend, while encouraging participation in resist-
ance training as an ongoing lifestyle choice. The importance of
effective education by qualified professionals is essential,
454041
as positive early experiences in physical education have been
associated with lifelong physical activity.
42
EFFECTS OF GROWTH AND MATURATION ON THE
DEVELOPMENT OF MUSCULAR STRENGTH DURING
CHILDHOOD AND ADOLESCENCE
It has been established previously that muscular strength devel-
opment is a multidimensional fitness component that is influ-
enced by a combination of muscular, neural and biomechanical
factors.
43
Due to the non-linear development of physiological
processes such as stature and body mass during childhood and
adolescence, the assessment and monitoring of muscular
strength can be a challenging task during the growing years.
44
Similarly, a non-linear pattern emerges when examining the
development of physical performance qualities in younger
populations.
3
Assessments of muscular strength in children and
adolescents indicate that strength increases in a relatively linear
fashion throughout childhood for both boys and girls.
45
As chil-
dren reach the onset of puberty, they experience rapid growth
along with observable non-linear gains in muscular strength.
46
During this period, sex differences in muscular strength begin to
emerge, with boys demonstrating accelerated gains as a result of
the adolescent spurt, and girls appearing to continue to develop
in a more linear fashion.
3
Potential factors inherently respon-
sible for increases in strength during childhood appear to be
related to the maturation of the central nervous system,
47
for
example, improvements in motor unit recruitment, firing fre-
quency, synchronisation and neural myelination.
48 49
Strength
gains during adolescence are typically driven by further neural
development, but structural and architectural changes resulting
largely from increased hormonal concentrations, including tes-
tosterone, growth hormone and insulin-like growth factor play a
significant role, especially in males.
2
Further increases in muscle
cross-sectional area, muscle pennation angle and continued
motor unit differentiation will typically enable adolescents to
express greater levels of force, and partly explain the age-related
differences in strength between children, adolescents and
adults.
50
The number of muscle fibres that an individual will
possess is determined as a result of prenatal myogenesis,
51
and
therefore it should be noted that postnatal increases in muscle
cross-sectional area will be largely governed by increases in
muscle fibre size, not an increase in the number of muscle
fibres.
51 52
Sex-related differences in muscular strength are more evident
as children enter adolescence, with males consistently outper-
forming females.
53
Research has indicated that muscle growth
will largely explain the disparity between sexes, especially for
absolute measures of muscular strength and power.
54 55
It is
essential that those responsible for teaching and training chil-
dren and adolescents are aware of these paediatric scientific
principles to ensure that an exercise prescription is planned
according to the unique demands of the individual inclusive of
baseline fitness levels, motor skill development, movement com-
petencies and health or medical issues. Owing to the highly
individualised nature of growth and maturation, children and
adolescents of the same chronological age will vary markedly in
biological status (up to 4–5 years), and consequently, chrono-
logical age is deemed a weak indicator of maturational status.
56
Awareness of the potential variation in biological age among
children of the same chronological age group is a central tenet
of most long-term physical development programmes in order
to ensure that youth are trained according to their biological
status, as opposed to age-group classifications.
457–62
In addition
to chronological and biological age, those responsible for the
design and implementation of youth resistance training pro-
grammes must take into consideration the training age of the
individual.
4
From a developmental perspective, this becomes
critically important when training an adolescent who is
approaching adulthood, but has no experience of participating
in a structured resistance training programme. Conversely, a
technically proficient 10-year-old child should not be restricted
to introductory training methods, provided they have the inter-
est and desire to participate in more advanced training
programmes.
463
HEALTH BENEFITS OF RESISTANCE TRAINING FOR YOUTH
The WHO now recognises physical inactivity as the fourth
leading risk factor for global mortality for non-communicable
diseases, and supports participation in a variety of physical activ-
ities including those that strengthen muscle and bone.
35
Since
contemporary youth are not as active as they should be,
64–67
children and adolescents should be encouraged to participate
regularly in play, games, sports and planned exercise in the
context of school and community activities. Not only is physical
activity essential for normal growth and development, but also
youth programmes that enhance muscular strength and funda-
mental movement skill performance early in life appear to build
the foundation for an active lifestyle later in life.
68–71
Since mus-
cular strength is an essential component of motor skill perform-
ance,
21272
developing competence and confidence to perform
resistance exercise during the growing years may have important
long-term implications for health, fitness and sports
performance.
73
2 Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952
Consensus statement
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Resistance training as part of a well-rounded fitness training
programme can offer unique health benefits to children and
adolescents when appropriately prescribed and supervised.
Regular participation in youth resistance training programme
has been shown to elicit favourable short-term influences on
musculoskeletal health, body composition and cardiovascular
risk factors.
11 74–77
However, following a period of detraining
(8–12 weeks) various measures of muscular fitness appear to
regress towards baseline values,
78–80
suggesting that engagement
in resistance training should be viewed as a long-term, year-
round commitment to a well-constructed and varied periodised
programme.
Given the growing prevalence of youth who are overweight
and obese and the associated health-related concerns, the influ-
ence of resistance training on the metabolic health, body com-
position and injury risk profile of children and adolescents with
excess body fat has received increased attention.
21 81–86
Although low intensity, long-duration aerobic exercise is typic-
ally prescribed for youth who are overweight or obese, excess
body fat and weight may hinder the performance of physical
activities such as jogging. Additionally, adolescents who are
overweight and obese are more than twice as likely to be injured
in sports and other physical activities compared with their peers
who are not overweight or obese, typically due to a reduced
ability to demonstrate and maintain postural stability.
84
Furthermore, youth deemed to be overweight and obese seem
to demonstrate significantly lower motor coordination than
normal weight youth,
87–89
which is of concern due to the estab-
lished relationship between motor coordination and levels of
physical activity.
70 90–92
While the treatment of youth who are
overweight and obese is complex, participation in a formalised
training programme that is inclusive of resistance training may
provide an opportunity to improve their muscle strength,
enhance motor coordination and gain confidence in their per-
ceived abilities to be physically active.
93 94
The available evidence indicates that resistance training has
the potential to offer observable health value to sedentary youth
and young athletes, and such training should always be designed
by qualified professionals to meet the needs of all children and
adolescents, regardless of body size or physical ability.
Resistance training and the growing skeleton
From a public health perspective, it is noteworthy that trad-
itional fears and misinformed concerns that resistance training
would be harmful to the developing skeleton have been replaced
by reports indicating that childhood may be the opportune time
to build bone mass and enhance bone structure by participating
in weight-bearing physical activities.
95–97
Fears that resistance
training would injure the growth plates of youths are not sup-
ported by scientific reports or clinical observations, which indi-
cate that the mechanical stress placed on the developing growth
plates from resistance exercise, or high strain eliciting sports
such as gymnastics or weightlifting, may be beneficial for bone
formation and growth.
29 98–102
While children have a lower risk
of resistance training-related injury to joint sprains and muscle
strains than adults,
103
attention to initial postural alignment and
technical competency during all exercises throughout the train-
ing programme is essential to ensure safe and effective practice
irrespective of resistance training mode. While numerous
factors, including genetics and nutritional status influence skel-
etal health, regular participation in sports and fitness pro-
grammes, which include multijoint, moderate-to-high intensity
resistance exercise, can help to optimise bone-mineral accrual
during childhood and adolescence.
23 24 97 104–110
In fact, the
literature suggests that childhood and adolescence are indeed
key developmental periods for increasing bone-mineral density,
and that failure to participate in moderate-to-vigorous weight-
bearing physical activity during these stages of growth may pre-
dispose individuals to long-term bone-health implica-
tions.
24 95 111
Furthermore, no scientific evidence indicates that
resistance training will have an adverse effect on linear growth
during childhood or adolescence
99 112
or reduce eventual height
in adulthood.
98–100
INJURY PREVENTION BENEFITS OF RESISTANCE TRAINING
FOR YOUTH
Although the total elimination of sport-related and physical
activity-related injuries is an unrealistic goal, multifaceted train-
ing programmes that include general and specific strength and
conditioning activities may help to reduce the likelihood of
injuries in youth. Cahill and Griffith
113
incorporated resistance
training into their preseason conditioning for adolescent
American football players and reported a reduction in non-
serious knee injuries, as well as knee injuries requiring surgery,
over four competitive seasons. Hejna et al
114
reported that ado-
lescent athletes who incorporated resistance training in their
physical development programme suffered fewer injuries and
recovered from injuries with less time spent in rehabilitation as
compared with team-mates who did not participate in a similar
resistance training programme. Similarly, Soligard et al
115
suc-
cessfully reduced the risk of severe and overuse injuries in
female adolescent soccer players, following the implementation
of a comprehensive warm-up programme that incorporated
resistance-based exercises. Likewise, Emery and Meeuwisse
116
reported a reduction in overall injuries and acute injury inci-
dence in adolescent soccer players with the use of an integrative
training programme that included resistance training. Of note,
recent evidence suggests that adherence of adolescent female
soccer players to injury prevention programmes is greater when
facilitated by appropriately skilled coaches.
117
This underscores
the importance of regular coach education to ensure that quali-
fied professionals understand the mechanical requirements of
correct exercise techniques, fundamental principles of paediatric
exercise science and the pedagogical aspects of coaching youth
training programmes.
Despite specific case study reports highlighting acute resist-
ance training-related injuries,
112 118 119
such injuries have gener-
ally occurred when youth are unsupervised or supervised by
individuals with unqualified instruction and/or inappropriate
training loads.
29
Recent data examining acute resistance
training-related injuries in youth and adults reveal that approxi-
mately 77.2% of all injuries are accidental
103
and that most
injuries are potentially avoidable with appropriate supervision,
sensible training progression based on technical competency and
a safe training environment.
29
With respect to overuse injuries,
literature indicates that appropriately prescribed and well-
supervised training programmes will reduce the likelihood of
overuse injuries occurring in youth populations
120–122
and that
resistance training focused on addressing the risk factors asso-
ciated with youth-sport injuries (eg, low-fitness level, muscle
imbalances and errors in training) has the potential to reduce
overuse injuries by approximately 50% in children and adoles-
cents.
26 123
For example, training protocols incorporated into
preseason and in-season conditioning programmes reduced
overuse injury risks, and decreased anterior cruciate ligament
(ACL) injuries in adolescent athletes.
124–128
It appears that multifaceted programmes that increase muscle
strength, enhance movement mechanics and improve functional
Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952 3
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abilities may be the most effective strategy for reducing sports-
related injuries in young athletes.
116 124 129 130
Additionally, the
effectiveness of these injury prevention programmes is greater if
implemented in younger age groups prior to the onset of neuro-
muscular deficits and biomechanical alterations.
130 131
Clearly,
participation in physical activity should not begin with competi-
tive sport but should evolve out of preparatory fitness condi-
tioning that is sensibly progressed over time. This notion is
supported by the fact that basic jumping and landing activities
commonly encountered within both competitive sports and free-
play activities can expose individuals to ground reaction forces
of approximately 5–7 times body weight,
132 133
which are in
excess of the forces experienced during resistance training
activities.
Since physical inactivity is a risk factor for activity-related
injuries in children,
134
youth who participate regularly in
age-appropriate fitness programmes, which include resistance
exercise, may be less likely to suffer an injury owing to the
apparent decline in free-time physical activity among children
and adolescents.
34 67 135–137
As such, it seems that the musculo-
skeletal system of some aspiring young athletes may be ill-
prepared for the demands of sports practice and competi-
tion.
25 29 138 139
Recent position statements have recognised the
importance of physical activity and sport for youth, and
promote the early identification of fitness deficits in aspiring
young athletes and the proper prescription of training pro-
grammes to address individual limitations.
140 141
Consequently,
aspiring young athletes should be encouraged to participate in,
and appreciate the value of, multifaceted preparatory condition-
ing programmes that include resistance training to address defi-
cits in muscular fitness and skill development, and enhance
symmetry in strength development around joints. Importantly,
for youth who participate in multiple sports or multiple leagues
within the same sport, resistance training sessions should not be
simply viewed as an addition to the overall sporting schedule,
but should form a compulsory component in lieu of additional
competitive events or sport-specific training sessions.
Resistance training considerations for young females
Musculoskeletal growth during puberty, in the absence of corre-
sponding neuromuscular adaptation, may facilitate the develop-
ment of abnormal joint mechanics and injury risk factors in
young adolescent girls.
142 143
If not addressed, these intrinsic
risk factors may continue to develop throughout adolescence,
thus predisposing female athletes to increased risk of
injuries.
144 145
In a recent longitudinal study, Ford et al
146
noted that young females who did not participate in resistance
training programmes as they matured developed injury risk
factors (eg, increased knee valgus moment when landing).
Conversely, those maturing athletes who did report participation
in resistance training activities were found to have safer move-
ment mechanics and increased posterior chain strength.
146
Well-supervised, multifaceted resistance training programmes
have been shown to reduce abnormal biomechanics (eg,
increased knee valgus landing) that manifest during adoles-
cence
127 128 147 148
and appear to decrease injury rates in
female athletes.
127
The findings of a recent meta-analysis
revealed that within existing literature, an age-related association
between resistance training and reduction of ACL incidence
only occurred in the youngest female athletes (14–18 years),
indicating that the earlier youth can engage with a well-rounded
training programme inclusive of resistance training, the lower
the likelihood of ACL injury.
130
Resistance training utilised to
enrich the motor learning environment in early youth may
initiate adaptation and help low-motor competence children
‘catch-up’with their peers in neuromuscular control.
149–153
In
addition to reduced knee injuries in adolescent
154
and
mature
155
female athletes, regular participation in a multifaceted
resistance training programme may also induce measures of the
‘neuromuscular spurt’,defined as the natural increases in muscle
power, strength and coordination that occurs with increasing
age in adolescent boys,
139
which are not typically seen in
females.
128 153
Of potential interest to sports medicine profes-
sionals, resistance training timed with growth and development
may induce the desired neuromuscular spurt, which may
improve sports performance and improve biomechanics related
to injury risk in young females.
128 144
Observed relative gains in
females can be greater than in males, perhaps because baseline
neuromuscular performance levels are lower on average in
females.
128 156–159
PSYCHOSOCIAL BENEFITS OF RESISTANCE TRAINING FOR
YOUTH
At present, research examining the psychological benefits of
resistance training for youth is limited, and the literature that is
available has thus far produced equivocal findings. While a
small number of studies have previously failed to demonstrate
significant resistance training-induced psychological benefits for
healthy youth,
112 160
other research indicates that physical activ-
ity interventions inclusive of resistance training can lead to
improvements in psychological well-being,
30 33
mood and self-
appraisal.
161
Of note, youth who possess relatively low levels of
self-concept at the start of an exercise programme may be more
likely to show significant improvement in comparison with
those who begin training with a relatively high self-concept.
160
Research indicates that self-concept and self-perception are
related to an individual’s level of engagement in physical activ-
ity.
162–166
It has been reported that adolescent girls improved
their physical self-perceptions in response to an 8-week resist-
ance training programme.
167
Similarly, various measures of self-
concept have been shown to improve in adolescent males and
females after a 12-week resistance training programme.
32
Collectively, these findings indicate that age-related resistance
training can have a favourable influence on the psychological
well-being of school-age youth provided that self-improvement
and enjoyment remain central to the training programme.
It should be noted that excessive volumes of physical training
(inclusive of resistance training) could lead to negative psycho-
social effects, especially for those youth who are emotionally
and psychologically vulnerable.
168
Excessive training with inad-
equate recovery may lead to a child or adolescent experiencing
overtraining syndrome, which is identified by prolonged mal-
adaptation of biological, neurochemical and hormonal systems.
In addition to physiological concerns, overtraining can have
serious psychosocial consequences
169
and may require substan-
tial time for a young athlete to make a full recovery.
170
This
highlights the need for appropriate prescription and supervision
by qualified professionals who listen to individual concerns and
understand the physical and psychological uniqueness of
younger populations.
EFFECTIVENESS OF YOUTH RESISTANCE TRAINING FOR
THE DEVELOPMENT OF MUSCLE STRENGTH, MOTOR SKILL
AND PHYSICAL PERFORMANCE
The term ‘trainability’describes the sensitivity of developing
athletes to a given training stimulus.
2
As previously documented,
children and adolescents will increase muscular strength levels
as a result of growth and maturation.
2356171172
Growth and
4 Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952
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maturation can obscure the effects of training, as they can quite
often mask potential training effects if the intensity and volume
of the conditioning programme are suboptimal.
169 173 174
The
appropriate development of muscular strength can have import-
ant implications for sport and daily life. To induce adaptations
in muscular strength above and beyond those of growth and
maturation alone, the volume and intensity of training stimulus
must be sufficient.
2 5 12 175 176
Research clearly indicates that
appropriately designed resistance training programmes can
benefit youth of all ages, with children as young as 5–6 years of
age making noticeable improvements in muscular fitness follow-
ing exposure to basic resistance training exercises using free
weights, elastic resistance bands and machine weights.
161 177–179
Irrespective of chronological age, it is recommended that any
child engaging in a form of resistance training is emotionally
mature enough to accept and follow directions, and possesses
competent levels of balance and postural control.
59
While
reports indicate that the magnitude of absolute strength gains is
greater in adolescents (effect size=1.91) in comparison to chil-
dren (effect size=0.81),
14
relative increases in strength appear
to be similar during the developmental periods of childhood
and adolescence.
119 180 181
It is acknowledged that muscular strength is important for
effective motor skill performance.
272
Findings from a recent
meta-analysis showed that resistance training is effective in
enhancing motor skill performance ( jumping, running and
throwing tasks), and that children showed greater gains in per-
formance than adolescents.
12
These findings, in addition to
several reviews
41314252974100180182
highlight the effective-
ness of resistance training for enhancing motor skill perform-
ance in school-age youth, and underscore the importance of
implementing progressive interventions early in life when chil-
dren possess higher levels of neural plasticity.
Despite the growing body of evidence demonstrating that
resistance training can lead to established improvements in
motor performance through increases in qualities such as
strength, speed, power and other related characteristics,
12
an
aspect of discussion among some observers relates to the degree
of training-induced muscle hypertrophy that is possible in chil-
dren prior to puberty.
169 183–185
Existing research suggests that
increases in muscular strength are a result of muscle cross-
sectional area, architectural (muscle size, moment arm length)
and neural (voluntary activation level) adaptations.
53 186
However, the mechanisms appear to differ according to the
stage of development and are tissue dependent (ie, muscle vs
tendon). The primary mechanism underlying resistance
training-induced gains in muscular strength and related charac-
teristics before puberty depend primarily on neural adapta-
tions.
2 49 187 188
However, among early and particularly late
adolescents, the effects of resistance training appear to be a
result of additional gains in lean body mass and muscle cross-
sectional area (especially in males); with further alterations in
neural mechanisms appearing to be the same as those adapta-
tions experienced by adults.
14 189
Therefore, the focus of resist-
ance training for children should be based on goals related to
enhancement of muscle strength, function and control, as
opposed to trying to make substantial increases in muscle size.
Indeed, when training children and adolescents the adoption of
a long-term approach to physical development should be imple-
mented with a clear understanding of the primary mechanisms
responsible for training-induced adaptations during different
stages of development.
441
Collectively, the existing literature highlights several import-
ant concepts. First, appropriate resistance training can result in
an increased level of strength during childhood and adoles-
cence.
12 14 182 190–195
Gains in maximum strength have ranged
from approximately 10% to 90%,
14
depending on several
factors including the volume, intensity, frequency, duration and
design of the training programme, as well as the quality of
supervision.
196
However, in general, expected strength gains of
30–40% are typically observed in untrained youth following
participation in an introductory (8–20 weeks) resistance training
programme.
5
Second, resistance training results in only a minor
sex-associated effect on both absolute and relative strength gains
among prepubertal children, however, the magnitude of effect
does appear to be a function of sex in older groups.
119
Third,
evidence indicates that the most effective programmes last more
than 8 weeks and involve multiple sets, and that generally
strength gains increase with the frequency of training sessions
per week.
12
Finally, following a short training programme,
detraining will be quite rapid.
78–80
Consequently, youth should
be encouraged to participate in year-round resistance training in
order to maintain training-induced gains in muscular strength. It
should be noted that resistance training programmes for youth
should follow a training model with a progressive and systematic
variation in exercise selection, intensity, volume, frequency and
repetition velocity to enhance training adaptations, reduce
boredom and decrease the risk of overuse injuries.
197–199
Qualified professionals should regularly assess the readiness of
youth to participate in resistance training sessions, and should
manipulate daily training sessions when appropriate.
Weightlifting for youth
The available literature indicates that participation in the sport
of weightlifting and the performance of weightlifting move-
ments as part of a strength and conditioning programme can be
safe, effective and enjoyable for children and adolescents pro-
vided qualified supervision and instruction are available and
progression is based on the technical performance of each
lift.
41 103 200–202
However, it must be emphasised that regardless
of the exercise choice, all youth resistance training programmes
should be consistent with a participant’s training age, technical
competency and maturational status. Additionally, qualified pro-
fessionals who are knowledgeable of youth resistance training
protocols and are able to teach and progress a variety of exer-
cises including weightlifting movements should instruct such
programmes.
Weightlifting exercises have previously been used by paediat-
ric researchers to examine the potential effects of strength-
power training on a number of performance and physiological
variables.
200 203 204
The data gleaned from these studies indicate
that the incorporation of weightlifting exercises into a training
programme can produce positive alterations in body compos-
ition, cardiorespiratory variables, various motor fitness para-
meters (eg, jumping and sprinting) and overall weightlifting
performance among youth.
200 203 204
Additionally, weightlifting
injury rate is reportedly lower than other forms of resistance
training and sports in general.
200 201
If training and competition
are properly supervised and sensibly progressed, then the per-
formance of weightlifting exercises may provide a safe and
effective stimulus for enhancing strength and power perform-
ance in school-age youth. Owing to the skill level required to
perform weightlifting movements correctly, it is important that
individuals responsible for teaching complex movements to
youth hold the requisite coaching qualifications, and have
experience teaching weightlifting to children and adolescents to
ensure their continued safety and well-being.
Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952 5
Consensus statement
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RESISTANCE TRAINING GUIDELINES FOR CHILDREN AND
ADOLESCENTS
Training variable considerations
Exercise selection
While a range of exercises performed using a variety of equip-
ment can be prescribed to both children and adolescents, it is
vital that the fundamentals of technical competency are priori-
tised at all times. The principles of equipment suitability and
familiarity for paediatric testing, also apply for youth participat-
ing in a resistance training programme. The use of child-size
equipment (light barbells, small dumbbells or fixed machine
weights) is important for children or adolescents to properly
and safely execute a movement with correct technique.
205
Some of the resistance modes available to those prescribing
youth resistance training programmes include bodyweight,
weight machines, free weights (ie, barbells and dumbbells),
elastic resistance bands and medicine balls; all of which have
been proven to elicit physiological adaptation and/or perform-
ance enhancement when used in youth resistance training
programmes.
17 21 79 80 112 128 153 177 190 206–217
The selection of the resistance modality will largely depend
on the technical ability and baseline fitness levels of the individ-
ual, the level of coaching expertise, the overall goal of the train-
ing programme and the availability of equipment. However,
when basic bodyweight exercise technique (eg, bodyweight
squatting, lunging, pressing and pulling movements) is suffi-
ciently developed in the individual, exercises with free weights
should be incorporated into the training programme since alter-
native forms of resistance such as machine-based resistance have
been reported to stimulate less muscle activation in lower
body,
218
upper body
219
and whole-body
220
exercises compared
with free-weight resistance, albeit in adult populations. For
technically competent youth, dynamic qualities can be
enhanced with multijoint, velocity-specific training in the form
of free-weight resistance training (eg, weightlifting and
plyometrics).
202 210 212
For youths with a minimal training experience and associated
poor technical competency (ie, low-training age), qualified pro-
fessionals should employ a range of exercises which are
designed to promote the development of muscular strength and
enhance overall fundamental motor skill competency.
Childhood is deemed to be a crucial time in which to develop
motor skill competency, as it is during these formative years that
neuromuscular coordination is most susceptible to change.
221
During this stage of development, children will experience rapid
brain maturation,
222
and exposing children to key athletic move-
ment patterns at a time where natural strengthening of existing
synaptic pathways
223
and synaptic pruning
224
takes place, is
considered crucial for long-term athletic development
4
and life-
long physical activity.
225
Once the child can demonstrate appro-
priate technical competency, they can be introduced to more
advanced exercises that challenge the child in terms of coordin-
ation and require greater levels and rates of force production. In
the case of weightlifting exercises, which by their nature are
more complex movements, researchers have previously sug-
gested that early exposure should focus on technical develop-
ment using modified equipment and light external loads.
541
Training volume and intensity
Volume and intensity are key resistance training variables that
are routinely manipulated within a training session, or overall
phase of training, depending on the primary training goal of the
individual. Volume refers to the total number of times an
exercise is performed within a training session multiplied by the
resistance used (kg).
197 226
Intensity most commonly refers to
the resistance that is required to overcome during a repeti-
tion.
226
The relationship between volume and intensity is
inverse in nature; the greater the load (intensity), the lower the
number of repetitions that can be completed (volume) by the
individual.
226
Both variables must be considered synergistically
when prescribing resistance training to maximise physiological
adaptation and minimise injury risk. Exposing a child or adoles-
cent to excessive intensity (external loading) at the expense of
correct technique may lead to acute injury, while prescribing
excessive volume of training over a training block may induce a
state of overtraining. This highlights the need for qualified pro-
fessionals to not only understand resistance training prescription
theory but also the unique intricacies associated with youth of
different ages and maturity levels.
To prescribe appropriate training intensity, teachers and
coaches typically stipulate a percentage of an individuals’one
repetition-maximum (1 RM). Research indicates that maximal
strength and power testing of children
227
and adolescents
228
is
safe and reliable when standardised protocols are implemented
and monitored by qualified professionals. While 1 RM measure-
ments are routinely used within paediatric research settings and
youth sport training facilities, owing to time and class size, phys-
ical education teachers and youth fitness professionals may
benefit from the use of alternative means of assessing strength.
Predictive equations that estimate 1 RM values from submaxi-
mal loads have been used in adult populations,
229–231
however,
methods of predicting 1 RM values from higher repetition
ranges possess less accuracy, in particular when repetition ranges
exceed more than 10.
227
Additionally, the fatiguing effects of
higher RM testing schemes (eg, 5 RM or 10 RM) are note-
worthy since the cumulative effects of fatigue will influence the
ability of a child or adolescent to maintain proper exercise tech-
nique throughout the testing set. If an overarching demonstra-
tion of muscular strength is the desired outcome, simple
field-based measures such as vertical jump, long jump and hand-
grip strength assessment have been significantly correlated to 1
RM strength values in youth and may serve as an appropriate
surrogate measure of muscular strength, especially in schools
and recreational settings.
232 233
Crucially, it should be noted
that a child or adolescent must be able to demonstrate sound
technical competency irrespective of the RM load or test
selected.
Progression of volume and intensity
When untrained or sedentary youth with a low-training age and
poor technical competency first begin to participate in forma-
lised resistance training programmes, the use of 1RM measure-
ments (actual or predicted) to determine training intensities will
typically be unnecessary. Consequently, an appropriate repeti-
tion range should be prescribed to develop technical compe-
tency and acquire a base level of adaptation, and over time the
external load can be increased provided exercise technique has
sufficiently improved. For individuals without prior experience
of resistance training, initial prescription should use low volume
(1–2 sets) and low-moderate training intensities (≤60% 1 RM)
for a range of exercises and movement patterns.
197
It should be
noted that when children are initially exposed to multijoint
resistance training exercises (eg, squatting), then multiple repeti-
tions might be counterproductive for motor control develop-
ment. Instead, it is recommended that children perform fewer
repetitions (1–3) and are provided with real-time feedback after
each repetition to ensure safe and correct movement
6 Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952
Consensus statement
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development. This is especially true for weightlifting exercises,
which will naturally require more frequent feedback owing to
the increased technical demands, associated with the move-
ments. Once basic exercise technique is competent, then pre-
scription should be progressed; for example, 2–4 sets of 6–12
repetitions with a low-moderate training intensity (≤80% 1
RM). Such progression should provide the child with sufficient
exposure in order to aid motor control development, while
serving as a suitable volume for physical conditioning. As train-
ing age and athletic competency increases, youth can be intro-
duced to periodic phases of lower repetition ranges (≤6) and
higher external loads (>85% 1 RM) in training, on the proviso
that technical competency remains.
15 77 200 234 235
However, it is important to note that not all exercises need to
be performed for the same number of sets and repetitions
within a training session. For example, an experienced adoles-
cent lifter may perform three sets of three repetitions of a
power-oriented exercise (eg, clean and jerk, snatch and deriva-
tives of these lifts); then complete three sets of 3–5 repetitions
of a large compound, multijoint movement (eg, back squat);
and then finish with two sets of 6–8 repetitions of a unilateral
exercise (eg, dumbbell lunge). Irrespective of the specificpre-
scription, qualified professionals must observe and monitor for
the effects of accumulated fatigue during the training session to
minimise the risks of fatigue-induced technique decrements,
which may predispose youth to training-related injury.
Depending on the learning environment, qualified profes-
sionals will need to provide feedback to ensure that technical
competency is maintained throughout each set of the training
programme. The frequency and mode of feedback will depend
to a large degree on the number of individuals training, type of
exercise being performed and the stage of learning and person-
ality traits of the youth involved. For example, when coaching a
novice, constructive feedback may be most helpful if it is pro-
vided after each repetition.
41
In physical education classes in
which the focus of the lesson is aimed at enhancing muscle
strength and fundamental motor skill development, constructive
feedback is most important since students are typically learning
the correct movement patterns for the first time.
Rest intervals during training sessions
Available research indicates that children can recover more
quickly from fatigue-inducing resistance training,
236 237
and
are less likely to suffer muscle damage following this form of
exercise, owing to the increased pliability of their muscle
tissue.
238
Therefore, rest periods of approximately 1 min
should suffice for most children. However, this may need to
be increased (eg, 2–3 min) as the intensity of training
increases, especially if the exercises require high levels of skill,
force or power production (eg, weightlifting or plyometric
exercises). While children can recover more quickly from
short, intermittent high-intensity exercise bouts than
adults,
236 237 239
within-session resistance training performance
should always be monitored to ensure correct resistance exer-
cise technique is maintained throughout the training session.
As such, commercial metabolic high-intensity resistance train-
ing programmes characterised by insufficient recovery between
sets and exercises may result in the performance of potentially
injurious exercise movements.
Training frequency
Training frequency typically refers to the number of sessions per-
formed within a week. Previous research has indicated that 2–3
sessions per week on non-consecutive days is most appropriate
in order to develop muscular strength levels in children and
adolescents.
5 240
Behringer et al
14
recently substantiated these
recommendations, indicating that across 42 studies (where mean
training frequency was 2.7±0.8 sessions/week), training fre-
quency was significantly correlated with increased resistance
training effect. Since youth are still growing and developing,
resistance training programmes should provide adequate time
for rest and recovery. Youth who participate in resistance train-
ing programmes with a high training frequency should be moni-
tored closely. Training frequency may increase as children go
through adolescence and approach adulthood, especially for
youth in competitive sport. While sampling and exposure to a
variety of physical activity experiences should be recommended
to help promote long-term physical development,
4225
parents,
coaches and fitness professionals should be cognisant of the
potential difficulties when youth participate in numerous activ-
ities resulting in the accumulation of high exercise volumes. For
youth participating in competitive sports, in-season resistance
training is needed to maintain gains in muscular fitness and
reduce injury-risk. However, to reduce the chances of non-
functional overreaching or overtraining, and to allow natural
growth processes to occur, resistance training should not simply
be viewed as an additional training session within the overall
youth training programme, but as an alternative commitment in
place of sport-specific training sessions and/or competitive fix-
tures. Depending on the competitive demands of the sport, any-
where between one and three resistance training sessions should
be completed in-season to enable the development (or at least
the maintenance) of previously acquired strength gains, and to
allow adequate time for rest and recovery. Increased lesson time
in physical education, taught by well-trained specialists may
hold a realistic and evidenced-based opportunity to increase
muscle strength and motor skill competency, which would facili-
tate an overall improvement in general physical fitness.
272137
Research demonstrates that exposure to resistance training with
qualified supervision during exercise lessons or physical educa-
tion classes does not have an adverse effect on after-school per-
formance in adolescent athletes.
241
Repetition velocity
While moderate movement velocities may typically be recom-
mended for youth when learning new movements or exercises,
there is also a need to promote the intention to move quickly to
develop motor unit recruitment patterns and firing frequencies
within the neuromuscular system.
242
A child with limited train-
ing experience may need to perform resistance exercises with a
moderate speed to maximise control and ensure correct tech-
nical development (eg, limb alignment, maintenance of correct
posture); however, a participant with a training history of
several months should be exposed to much greater movement
velocities. Repetition velocities may also fluctuate within a
session; for example, the movement preparation phase (includ-
ing low load technical warm-up exercises) may consist of slower,
controlled movements, however, the main strength and power
exercises (inclusive of weightlifting and plyometric exercises)
will involve rapid movement speeds. For resistance training
exercises, the mass of the resistance will govern the velocity at
which the movement is performed. Although heavy strength
development exercises such as squatting, deadlifting, pressing
and pulling will typically involve slower movement velocities,
there should always be an intention to move as explosively as
possible to promote appropriate neuromuscular adaptations and
to maximise the transfer of training effect,
243
providing the
individual can demonstrate appropriate technique. The
Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952 7
Consensus statement
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development of high velocity movement may be especially
important during the growing years when neural plasticity and
motor coordination are most sensitive to change.
224
SUMMARY
A compelling body of scientific evidence supports participation
in appropriately designed youth resistance training programmes
that are supervised and instructed by qualified professionals.
The current article has added to previous position statements
from medical and fitness organisations, and has outlined the
health, fitness and performance benefits associated with this
training for children and adolescents. In summarising this
manuscript, it is proposed that
1. The use of resistance training by children and adolescents is
supported on the proviso that qualified professionals design
and supervise training programmes that are consistent with
the needs, goals and abilities of younger populations.
2. Parents, teachers, coaches and healthcare providers should
recognise the potential health and fitness-related benefits of
resistance exercise for all children and adolescents. Youth
who do not participate in activities that enhance muscle
strength and motor skills early in life may be at increased
risk for negative health outcomes later in life.
3. Appropriately designed resistance training programmes may
reduce sports-related injuries, and should be viewed as an
essential component of preparatory training programmes for
aspiring young athletes.
4. Regular participation in a variety of physical activities that
include resistance training during childhood and adolescence
can support and encourage participation in physical activity
as an ongoing lifestyle choice later in life.
5. Resistance training prescription should be based according to
training age, motor skill competency, technical proficiency
and existing strength levels. Qualified professionals should
also consider the biological age and psychosocial maturity
level of the child or adolescent.
6. The focus of youth resistance training should be on develop-
ing the technical skill and competency to perform a variety of
resistance training exercises at the appropriate intensity and
volume, while providing youth with an opportunity to par-
ticipate in programmes that are safe, effective and enjoyable.
Author affiliations
1
Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, Wales, UK
2
Department of Health and Exercise Science, The College of New Jersey, Ewing,
New Jersey, USA
3
Center of Excellence for Sport Science and Coach Education, East Tennessee State
University, Johnson City, Tennessee, USA
4
Faculty of Health, Sport and Science, University of South Wales, UK
5
Widnes Vikings Rugby League Club, Widnes, UK
6
Department of Kinesiology and Health Science, Shreveport, Louisiana State
University, Louisiana, USA
7
Division of Sports Medicine, Cincinnati Children’s Hospital Medical Center,
Cincinnati, Ohio, USA
8
Department of Kinesiology, Temple University, Philadelphia, Pennsylvania, USA
9
School of Health Sciences, University of Salford, Salford, UK
10
National Collegiate Athletic Association (NCAA), Indianapolis, Indiana, USA
11
Department of Orthopaedics, Division of Sports Medicine, Boston Children’s
Hospital, Boston, Massachusetts, USA
12
Harvard Medical School, Boston, Massachusetts, USA
13
The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts, USA
14
Faculty of Sport and Exercise Medicine (FSEM), Edinburgh, UK
15
Human Performance Laboratory, Department of Kinesiology, University of
Connecticut, Storrs, Connecticut, USA
16
Division of Cardiology, The Children’s Hospital of Philadelphia, Philadelphia,
Pennsylvania, USA
17
Division of Sports Medicine, Department of Family Medicine, Sports Health and
Performance Institute, Ohio State University, Ohio, USA
18
Rocky Mountain University of Health Professions, Provo, Utah, USA
19
Athercare Fitness and Rehabilitation, Alameda, California, USA
20
Athletic Training Division, School of Allied Medical Professions, The Ohio State
University, Columbus, Ohio, USA
Competing interests None.
Patient consent Obtained.
Provenance and peer review Commissioned; internally peer reviewed.
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12 Lloyd RS, et al.Br J Sports Med 2013;0:1–12. doi:10.1136/bjsports-2013-092952
Consensus statement
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published online September 20, 2013Br J Sports Med
Rhodri S Lloyd, Avery D Faigenbaum, Michael H Stone, et al.
training: the 2014 International Consensus
Position statement on youth resistance
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