Youth resistance training: position Statement paper and literature review

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YOUTH RESISTANCE TRAINING:UPDATED POSITION
STATEMENT PAPER FROM THE NATIONAL STRENGTH
AND CONDITIONING ASSOCIATION
AVERY D. FAIGENBAUM,
1
WILLIAM J. KRAEMER,
2
CAMERON J. R. BLIMKIE,
3
IAN JEFFREYS,
4
LYLE J. MICHELI,
5
MIKE NITKA,
6
AND THOMAS W. ROWLAND
7
1
Department of Health and Exercise Science, The College of New Jersey, Ewing, New Jersey 08628;
2
Department of Kinesiology,
University of Connecticut, Storrs, Connecticut;
3
Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada;
4
Department of Science and Sport, University of Glamorgan, Pontypridd, Wales, United Kingdom;
5
Division of Sports Medicine,
Children’s Hospital, Boston, Massachusetts;
6
Health and Physical Education Department, Muskego High School, Muskego,
Wisconsin; and
7
Department of Pediatrics, Baystate Medical Center, Springfield, Massachusetts
ABSTRACT
Faigenbaum, AD, Kraemer, WJ, Blimkie, CJR, Jeffreys, I, Micheli,
LJ, Nitka, M, and Rowland, TW. Youth resistance training:
Updated position statement paper from the National Strength
and Conditioning Association. J Strength Cond Res 23(5):
S60–S79, 2009—Current recommendations suggest that
school-aged youth should participate daily in 60 minutes or
more of moderate to vigorous physical activity that is develop-
mentally appropriate and enjoyable and involves a variety of
activities (219). Not only is regular physical activity essential for
normal growth and development, but also a physically active
lifestyle during the pediatric years may help to reduce the risk
of developing some chronic diseases later in life (196). In
addition to aerobic activities such as swimming and bicycling,
research increasingly indicates that resistance training can offer
unique benefits for children and adolescents when appropri-
ately prescribed and supervised (28,66,111,139,147,234).
The qualified acceptance of youth resistance training by medi-
cal, fitness, and sport organizations is becoming universal
(5,6,8,12,18,33,104,167,192,215).
Nowadays, comprehensive school-based programs are specif-
ically designed to enhance health-related components of phy-
sical fitness, which include muscular strength (169). In addition,
the health club and sport conditioning industry is getting more
involved in the youth fitness market. In the U.S.A., the number
of health club members between the ages of 6 and 17 years
continues to increase (127,252) and a growing number of
private sport conditioning centers now cater to young athletes.
Thus, as more children and adolescents resistance train in
schools, health clubs, and sport training centers, it is imperative
to determine safe, effective, and enjoyable practices by which
resistance training can improve the health, fitness, and sports
performance of younger populations.
The National Strength and Conditioning Association (NSCA)
recognizes and supports the premise that many of the benefits
associated with adult resistance training programs are attain-
able by children and adolescents who follow age-specific
resistance training guidelines. The NSCA published the first
position statement paper on youth resistance training in 1985
(170) and revised this statement in 1996 (72). The purpose of
the present report is to update and clarify the 1996 recom-
mendations on 4 major areas of importance. These topics
include (a) the potential risks and concerns associated with
youth resistance training, (b) the potential health and fitness
benefits of youth resistance training, (c) the types and amount
of resistance training needed by healthy children and adoles-
cents, and (d) program design considerations for optimizing
long-term training adaptations. The NSCA based this position
statement paper on a comprehensive analysis of the pertinent
scientific evidence regarding the anatomical, physiological, and
psychosocial effects of youth resistance training. An expert
panel of exercise scientists, physicians, and health/physical
education teachers with clinical, practical, and research exper-
tise regarding issues related to pediatric exercise science,
sports medicine, and resistance training contributed to this
statement. The NSCA Research Committee reviewed this
report before the formal endorsement by the NSCA.
For the purpose of this article, the term children refers to boys
and girls who have not yet developed secondary sex character-
istics (approximately up to the age of 11 years in girls and 13
years in boys; Tanner stages 1 and 2 of sexual maturation). This
period of development is referred to as preadolescence. The
term adolescence refers to a period between childhood and
POSITION STATEMENT
Address correspondence to Avery Faigenbaum, faigenba@tcnj.edu.
23(Supplement 5)/S60–S79
Journal of Strength and Conditioning Research
Ó2009 National Strength and Conditioning Association
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adulthood and includes girls aged 12–18 years and boys aged
14–18 years (Tanner stages 3 and 4 of sexual maturation). The
terms youth and young athletes are broadly defined in this
report to include both children and adolescents.
By definition, the term resistance training refers to a specialized
method of conditioning, which involves the progressive use of
a wide range of resistive loads and a variety of training
modalities designed to enhance health, fitness, and sports
performance. Although the term resistance training, strength
training, and weight training are sometimes used synonymously,
the term resistance training encompasses a broader range of
training modalities and a wider variety of training goals. The
term weightlifting refers to a competitive sport that involves the
performance of the snatch and clean and jerk lifts.
This article builds on previous recommendations from the
NSCA and should serve as the prevailing statement regarding
youth resistance training. It is the current position of the NSCA
that:
1. A properly designed and supervised resistance training
program is relatively safe for youth.
2. A properly designed and supervised resistance training
program can enhance the muscular strength and power of
youth.
3. A properly designed and supervised resistance training
program can improve the cardiovascular risk profile of
youth.
4. A properly designed and supervised resistance training
program can improve motor skill performance and may
contribute to enhanced sports performance of youth.
5. A properly designed and supervised resistance training
program can increase a young athlete’s resistance to sports-
related injuries.
6. A properly designed and supervised resistance training
program can help improve the psychosocial well-being
of youth.
7. A properly designed and supervised resistance training
program can help promote and develop exercise habits
during childhood and adolescence.
KEY WORDS strength training, weight training, weightlifting,
children, adolescents
LITERATURE REVIEW
Risks and Concerns Related to Youth Resistance Training
During the 1970s and 1980s, one of the reasons that
resistance training was not often recommended
for children and adolescents was the presumed
high risk of injury associated with this type of
exercise. In part, the widespread fear of injury associated with
youth resistance training during this era stemmed from data
gathered by the National Electronic Injury Surveillance
System (NEISS) of the U.S. Consumer Product Safety
Commission. NEISS uses data from various emergency room
departments to make nationwide projections of the total
number of injuries related to exercises and equipment
(231,232). However, NEISS data are based on injuries that
patients state are related to resistance exercise and
equipment, and therefore, it is incorrect to conclude that
the injuries were caused by such activities and devices. In fact,
many of the reported injuries were actually caused by
inappropriate training techniques, excessive loading, poorly
designed equipment, ready access to the equipment, or lack
of qualified adult supervision. Although these findings
indicate that the unsupervised and improper use of resistance
training equipment may be injurious, it is misleading to
generalize these findings to properly designed and supervised
youth resistance training programs.
Current findings from prospective resistance training
studies indicate a low risk of injury in children and adolescents
who follow age-appropriate training guidelines. In the vast
majority of published reports, no overt clinical injuries have
been reported during resistance training. Although various
resistance training modalities and a variety of training regi-
mens have been used, all the training programs were super-
vised and appropriately prescribed to ensure that the training
program was matched to the initial capacity of the participant.
Only 3 published studies have reported resistance training–
related injuries in children (a shoulder strain that resolved
within 1 week of rest (187), a shoulder strain that resulted in
1 missed training session (144), and a nonspecific anterior
thigh pain that resolved with 5 minutes of rest (198)). In a
report (187), there was no evidence of either musculoskeletal
injury (measured by biphasic scintigraphy) or muscle
necrosis (determined by serum creatine phosphokinase
levels) after 14 weeks of progressive resistance training.
Youth resistance training, as with most physical activ-
ities, does carry with it some degree of inherent risk of
musculoskeletal injury, yet this risk is no greater than many
other sports and recreational activities in which children and
adolescents regularly participate. In a prospective study that
evaluated the incidence of sports-related injuries in school-
aged youth over a 1-year period (258), resistance training
resulted in 0.7% of 1576 injuries whereas football, basketball,
and soccer resulted in approximately 19, 15, and 2%,
respectively, of all injuries. When the data were evaluated
in terms of injury to participant ratio in school team sports,
football (28%), wrestling (16.4%), and gymnastics (13%) were
at the top of the list. In general, injuries related to resis-
tance training in high school athletes appear to involve the
aggressive progression of training loads or improper exercise
technique (31,35,108,197).
Findings from the 2005–2006 High School Sports-Related
Injury Surveillance Study revealed that participation in team
sports resulted in an estimated 1.4 million injuries at a rate of
2.4 injuries per 1,000 athlete exposures (i.e., practices and
competition) (45). Of the 9 sports studied, football had the
highest injury rate (4.36 injuries per 1,000 athlete exposures),
whereas boys’ baseball (1.19) and girls’ softball (1.13) had the
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lowest injury rates (45). Although data comparing the relative
safety of resistance training, weightlifting, and other sports
are limited, in a retrospective evaluation of injury rates in
adolescents it was revealed that resistance training and
weightlifting were markedly safer than many other sports
and activities (114). In the aforementioned report (114), the
overall injury rate per 100 participant hours was 0.8000 for
rugby and 0.0120 and 0.0013 for resistance training and
weightlifting, respectively. This later finding may be explained,
at least in part, by the fact that the sport of weightlifting is
typically characterized by well-informed coaches and a
gradual progression of training loads, which are required to
effectively learn the technique of advanced multi-joint lifts.
With qualified instruction and a stepwise progression of the
training program, researchers have reported significant gains
in muscular strength without any report of injury when
weightlifting movements (snatch; clean and jerk; and
modified cleans, pulls, and presses) were incorporated into
a youth resistance training program (74,105,198,204).
In support of these observations, others have evaluated the
incidence of injury in young weightlifters and concluded that
competitive weightlifting can be a relatively safe sport for
children and adolescents provided that age-appropriate
training guidelines are followed and qualified coaching is
available (38,182). Because weightlifting movements involve
more complex neural activation patterns than other resis-
tance exercises, childhood may be the ideal time to develop
the coordination and skill technique to perform these lifts
correctly (57). To date, no scientific evidence indicates that
properly performed and sensibly progressed weightlifting
movements performed during practice or competition are
riskier than other sports and activities in which youth
regularly participate. Nevertheless, due to the potential for
injury during the performance of multi-joint free weight
exercises (190), youth coaches should be aware of the
considerable amount of time it takes to teach these lifts and
should be knowledgeable of the progression from basic
exercises (e.g., front squat) to skill transfer exercises (e.g.,
overhead squat) and finally to the competitive lifts (snatch
and clean and jerk).
Another concern related to youth resistance training
regards the safety and suitability of plyometric training (also
called stretch-shortening cycle exercise) for children and
adolescents. Unlike traditional strength-building exercises,
plyometric training conditions the body through dynamic
movements, which involve a rapid eccentric muscle action
that is immediately followed by a rapid concentric muscle
action (47,97). When the stretching and shortening of
a muscle are performed quickly, the force generated during
the muscle action is greater than the force that would be
generated if the muscle were not stretched immediately
before the muscle action (97). The contention that age-
appropriate plyometric training is unsafe for youth or that
a predetermined baseline level of strength (e.g., 1 repetition
maximum [1RM] squat should be 1.5 times body weight)
should be a prerequisite for lower-body plyometric training is
not supported by current research and clinical observations.
Indeed, comprehensive resistance training programs that
include plyometric exercises have been found to enhance
movement biomechanics, improve functional abilities, and
decrease the number of sports-related injuries in young
athletes (115,120,143,149,168).
Research studies indicate that plyometric training
can be a safe and worthwhile method of conditioning
for youth if appropriately prescribed and implemented
(56,69,75,125,134,143,150,151,202). Although plyometric
exercises typically include hops and jumps that exploit the
muscles’ cycle of lengthening and shortening to increase
muscle power, watching children on a playground supports
the premise that the movement pattern of boys and girls as
they skip and jump can be considered plyometric. For
example, when a child plays hopscotch and jumps from
square to square, the quadriceps stretch eccentrically when
the child lands and then they shorten concentrically when
the child jumps. This type of exercise, although game like in
nature, actually conditions the body to increase speed of
movement and improve power production (47). Nonetheless,
there is the potential for injury or illness to occur if the
intensity, volume, or frequency of plyometric training exceed
the abilities of the participants. In a case report, a 12-year-old
boy developed exertional rhabdomyolysis after he was in-
structed to perform excessive (.250) repetitive squat jumps
in a physical education class (48).
A traditional area of concern related to youth resistance
training is the potential for training-induced damage to the
growth cartilage, which is found at 3 main sites in a growing
child’s body: the growth plates near the ends of the long
bones, the cartilage lining the joint surfaces (articular
cartilage), and the points at which the major tendons attach
to the bones (apophysis) (161). Because growth cartilage is
‘‘pre-bone,’’ it is weaker than adjacent connective tissue and
therefore more easily damaged by repetitive microtrauma
(161). In some cases, damage to this area of the bone could
result in time lost from training, significant discomfort, and
growth disturbances (41). A few retrospective case reports
published in the 1970s and 1980s noted injury to the growth
cartilage during preadolescence (108) and adolescence
(25,31,108,128,194,197). However, most of these injuries
were due to improper lifting techniques, maximal lifts, or lack
of qualified adult supervision.
Although children and adolescents are susceptible to injury
to the growth cartilage, the potential for this type of injury
may be less in a preadolescent child than in an adolescent
because the growth cartilage may actually be stronger and
more resistant to sheering type forces in younger children
(160). To date, injury to the growth cartilage has not been
reported in any prospective youth resistance training
research study. Furthermore, there is no evidence to suggest
that resistance training will negatively impact growth and
maturation during childhood and adolescence (91,147).
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The potential for repetitive-use soft-tissue injuries is
another concern related to youth resistance training. This
type of injury often does not always cause children or
adolescents to go to the emergency room or even to see
a physician, so the incidence of these injuries is more difficult
to determine. Nevertheless, lower back pain among youth has
become a significant public health issue with prevalence rates
in adolescents approaching those in adults (9,131). In several
reports, lower back pain was the most frequent injury in high
school athletes who participated in resistance training
programs (31,35,190). In a study that involved adolescent
powerlifters who presumably trained with maximal or near-
maximal resistances, it was revealed that 50% of reported
injuries were to the lower back (35). Although many factors
need to be considered when evaluating these data (e.g.,
exercise technique and progression of training loads), the
importance of general physical fitness and lower back health
should not be overlooked. Because insufficient strength,
muscular endurance, and stability in the lower back have
been associated with current and future lower back pain in
adolescents (9,211), there is a role for preventive interven-
tions that include resistance exercise to possibly reduce the
prevalence or severity of lower back pain in youth.
Of note, there is an increased risk of injury to children and
adolescents who use exercise equipment at home (107,132).
It has been reported that young children are more likely to be
injured from home exercise equipment than older age groups
due, in part, to unsafe behavior, equipment malfunction, and
lack of supervision (132). There is also the potential for
a catastrophic injury if safety standards for youth resistance
training are not followed. In a case study report, a 9-year-old
boy died when a barbell rolled off a bench press support
and fell on his chest (102). These findings underscore the
importance of providing close supervision and safe training
equipment for all youth resistance training programs.
Any exercise or activity recommendation for children and
adolescents has risks as well as benefits. The risk of injury
while resistance training or weightlifting can be minimized by
qualified supervision, appropriate program design, sensible
progression, and careful selection of training equipment.
In addition, the risk of injury can be minimized by limiting the
number of heavy lifts during a workout, allowing for adequate
recovery between training sessions, and listening to each
child’s questions and concerns. In general, the risk of injury
associated with resistance training is similar for youth and
adults. There are no justifiable safety reasons that preclude
children or adolescents from participating in such a resistance
training program.
Effectiveness of Youth Resistance Training
During childhood and adolescence, physiologic factors
related to growth and development are in a constant state
of evolution. Due to the progression of growth, it can be
expected that healthy children will show noticeable gains in
height, weight, maximal oxygen uptake, anaerobic capacity,
and muscle strength during the developmental years (195).
Although different children do not follow the same rates of
change, performance variables such as grip strength normally
increase from childhood through the early teenage years
(148). Consequently, strength changes from low-volume
(sets 3repetitions 3load), short-duration resistance training
programs may not be distinguishable from gains due to
normal growth and development (59,117). To differentiate
training adaptations from those of normal growth and
development, it is apparent that an adequate training stimulus
and a prolonged training period are required.
A compelling body of scientific evidence indicates that
children and adolescents can significantly increase their
strength—above and beyond growth and maturation—
providing that the resistance training program is of sufficient
intensity, volume, and duration (30,55,70,74,77,79,80,86–88,
92,144,180,183,186,199,205,210,221,227,238,246,248,250).
In addition, 2 meta-analyses on youth resistance training
indicated mean effect sizes of 0.57 and 0.75 (94,179). Collec-
tively, these findings along with clinical observations and
evidence-based reviews (28,66,111,139,147,200,234) indicate
that well-designed resistance training programs can enhance
the muscular strength of children and adolescents beyond
that which is normally due to growth and development.
Children as young as 5 and 6 years have benefited from
regular participation in a resistance training program (11,86,
246), although most samples typically spanned several years
(e.g., 7 to 12 years of age). While a majority of training studies
had a duration of 8–20 weeks (79,80,92,118,144,186,205,
210,246), studies lasting 2–3 school years have been reported
(93,198). A wide variety of resistance training programs from
single set sessions on weight machines (249) to progressive,
multi-set training protocols on different types of equipment
(22,74,105,186,198,238) have proven to be efficacious.
Training modalities have included weight machines (both
adult (55,180,238,239) and child size (79,80,86,183,249)), free
weights (22,55,74,94,105,198,199), hydraulic machines (30,246),
pneumatic machines (205), medicine balls (77,221); elastic
bands (11), isometric contractions (101,117,174), and body
weight exercises (17,92,210,236). As previously observed in
adult populations, training adaptations that occur in youth
are specific to the muscle action or muscle groups that are
trained (97,174).
Strength gains up to 74% (88) have been reported after
8 weeks of progressive resistance training, although gains of
roughly 30% are typically observed after short-term (8–20
weeks) youth resistance training programs. Reported relative
(% change above initial levels) strength gains achieved during
preadolescence are equal to if not greater than the relative
gains observed during adolescence (144,174,180,248). Adult
athletes tend to be stronger than adolescent athletes (14), and
there is no clear evidence of any major difference in strength
between preadolescent boys and girls (27,81,200). In terms of
absolute strength gains, it appears that adolescents make
greater gains than children (144,200,239) and adults make
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greater gains than young adolescents (199), although some
findings are at variance with this suggestion (248).
Persistence of Training-Induced Strength Gains
The evaluation of strength changes in youth after the tem-
porary or permanent reduction or withdrawal of a training
stimulus (referred to as detraining) is complicated by the con-
comitant growth-related strength increases during the same
period. Although relative information regarding the effects of
detraining on younger populations is not extensive, the
available data suggest that training-induced gains in strength
and power in children are impermanent and tend to regress
toward untrained control group values during the detraining
period (29,87,125,205,227). The precise nature of the detrain-
ing response and the physiological adaptations that occur
during this period remain uncertain, although changes in
neuromuscular functioning and the hormonal responses to
resistance training and detraining should be considered. Of
interest, researchers found that training-induced increases in
the levels of testosterone and free androgen index in children
were maintained during an 8-week detraining period despite
the regression of strength toward untrained control group
values during this phase of the study (226,227).
Only a limited number of studies have evaluated the effects
of training frequency on the maintenance of strength and
power in children and adolescents. After 20 weeks of progres-
sive resistance training, a once-weekly maintenance training
program was not adequate to maintain the training-induced
strength gains in preadolescent males (29). Conversely, a
once-weekly maintenance program was just as sufficient as a
twice-weekly maintenance program in retaining the strength
gains made after 12 weeks of resistance training in a group of
adolescent male athletes (55). Others observed that children
who participated in a 10-week plyometric training program
were able to maintain training-induced gains in power after
8 weeks of reduced training, which included soccer practice
(56). Clearly, more research is needed before specific main-
tenance training recommendations can be made.
Program Evaluation and Testing
Factors such as previous exercise experience, program design,
specificity of testing and training, choice of equipment, quality
of instruction, and whether or not the learning effect was
controlled for in the study can directly influence the degree
of measured strength change. In addition, the methods of
evaluating changes in muscular strength consequent to
training are noteworthy considerations. In some studies, the
subjects were trained and tested using different modalities
(180,205,246), and in other published reports, strength
changes were evaluated by relatively high RM values (e.g.,
10RM) (74,88,144,248). Strength changes have also been
evaluated by maximal load lifting (e.g., 1RM) on the equip-
ment used in training (22,55,79,80,118,178,183,186,198,238).
Some clinicians and researchers have not used 1RM testing
to evaluate training-induced changes in muscular strength
because of the presumption that high-intensity loading may
cause structural damage in children. Thus, the maximal force
production capabilities of children have not been directly
evaluated in some studies. Yet no injuries have been reported
in prospective studies that utilized adequate warm-up periods,
appropriate progression of loads, close and qualified super-
vision, and critically chosen maximal strength tests (1RM
performance lifts, maximal isometric tests, and maximal
isokinetic tests) to evaluate resistance training–induced
changes in children. In a study, 96 children performed a
1RM strength test on 1 upper-body and 1 lower-body
weight machine exercise (81). No abnormal responses or
injuries occurred during the study period, and the testing
protocol was reportedly well tolerated by the subjects.
In other reports, children and adolescents safely per-
formed 1RM strength tests using free weight exercises
(14,22,118,124,142,152,153,178,198,238).
Paradoxically, most of the forces that youth are exposed to
in various sports and recreational activities are likely to be
greater in both exposure time and magnitude than compe-
tently supervised and properly performed maximal strength
tests. These observations along with current research findings
indicate that the maximal force–producing capabilities of
healthy children and adolescents can be safely evaluated by
1RM testing procedures, provided that youth participate in an
habituation period before testing to learn proper exercise
technique and qualified professionals closely supervise and
administer each test. Detailed procedures for evaluating 1RM
strength are available elsewhere (81,140).
Although maximal strength testing can be used to evaluate
training-induced changes in muscular strength in children
and adolescents in clinical and recreational settings, when
properly administered 1RM tests are labor intensive and time
consuming. Thus, in some instances (e.g., physical education
class) the use of field-based measures may be more
appropriate and time efficient. Researchers have documented
significant correlations between 1RM strength and common
field measures (e.g., handgrip strength and long jump) in
children (164). In any case, unsupervised and improper 1RM
testing (e.g., inadequate progression of loading and poor
lifting technique) should not be performed by children or
adolescents under any circumstances due to the real risk of
injury (189,190).
Physiological Mechanisms for Strength Development
In children it appears that training-induced strength gains are
more related to neural mechanisms than to hypertrophic
factors (139,147,178,186,200). Without adequate levels of
circulating testosterone to stimulate increases in muscle size,
children appear to experience more difficulty increasing their
muscle mass consequent to a resistance training program
(up to 20 weeks) as compared with older populations
(178,186,239). However, because some findings are at
variance with this suggestion (100,158), it cannot be stated
a priori that resistance training will not increase the muscle
mass of prepubescent youth. It is possible that more intensive
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training programs, longer training durations, and more
sensitive measuring techniques that are ethically appro-
priate for this population may be needed to partition the
effects of training on fat free mass from expected gains due to
growth and maturation.
Without corresponding increases in fat-free mass, it appears
that neural adaptations (i.e., a trend toward increased motor
unit activation and changes in motor unit coordination,
recruitment, and firing) (178,186) and possibly intrinsic
muscle adaptations (as evidenced by increases in twitch
torque) (186) are primarily responsible for training-induced
strength gains during preadolescence. Improvements in
motor skill performance and the coordination of the involved
muscle groups may also play a significant role because
measured increases in training-induced strength are typically
greater than changes in neuromuscular activation (178,186).
Although speculative, developmental alterations in muscle
fiber architecture (e.g., pennation angle) and changes in cen-
tral inhibitory influences on maximal muscle strength should
also be considered (195). In support of these observations,
several training studies have reported significant improve-
ments in strength during preadolescence without corre-
sponding increases in gross limb morphology, as compared
with a similar control group (88,144,178,186,199,246).
During puberty, testicular testosterone secretion in males is
associated with considerable increases in fat-free mass and
linear growth (139,195). Training-induced strength gains
during and after puberty in males may therefore be associated
with changes in hypertrophic factors because testosterone
and other hormonal influences on muscle hypertrophy
would be operant (139). Smaller amounts of testosterone in
females (resulting from enzymatic conversion of androgenic
precursors in the adrenal gland) limit the magnitude of
training-induced increases in muscle hypertrophy (195,200).
Other hormone and growth factors (e.g., growth hormone
and insulin-like growth factors) may be at least partly
responsible for muscle development in females (135).
Potential Health and Fitness Benefits
There are many health and fitness benefits associated with
regular physical activity in children and adolescents. Not only
is habitual physical activity essential for normal growth and
development, but also participation in age-appropriate fitness
programs can enhance the physical and psychosocial well-
being of youth. Although a majority of the pediatric research
has focused on activities that enhance cardiorespiratory fitness
(195), recent findings indicate that resistance training can offer
unique benefits for children and adolescents when appropri-
ately prescribed and supervised. As previously observed in
adults (97), regular participation in a resistance training
program has the potential to positively influence several
measurable indices of health and fitness. Youth resistance
training can improve one’s cardiovascular risk profile, facilitate
weight control, strengthen bone, enhance psychosocial well-
being, improve motor performance skills, and increase a young
athletes’ resistance to sports-related injuries.
Research that supports the utility of youth resistance
training in the acquisition of favorable degrees of health-
associated characteristics is expanding (67,147,219). More-
over, the contention that the overall health of children and
adolescents is likely to improve rather than be adversely
affected by regular participation in a resistance training
program is supported by statements from professional
organizations (8,18,33,167,192). Although good health habits
established during childhood do not always carry over into
adulthood, the potential positive influence of these habits on
the adult lifestyle should be recognized (146,196,222,225).
Hence, a compelling reason to encourage children and
adolescents to participate regularly in physical activity is to
reduce their risk of developing adult diseases later in life.
Cardiovascular Risk Profile. The potential influence of resis-
tance training on body composition (the percentage of total
body weight that is fat compared with the percentage that is
fat free) has become an important topic of investigation, given
that the prevalence of obesity among children and adoles-
cents continues to increase worldwide (175,240). Today,
childhood obesity, with its associated comorbidities such as
type 2 diabetes and likelihood of persistence into adulthood,
is a critical public health threat (126). Although genetic,
psychosocial, economic, and environmental factors likely
play a role in the development of obesity during childhood
and adolescence (4,62), it is becoming more apparent that the
increasing prevalence of obesity among school-aged youth
may be due, at least in part, to a sedentary lifestyle (62,106).
Although obese youth have traditionally been encouraged
to participate in aerobic activities, excess body weight hinders
the performance of weight-bearing physical activities such
as jogging and increases the risk of musculoskeletal overuse
injuries. Furthermore, obese youth often lack the motor skills
and confidence to be physically active, and they may actually
perceive prolonged periods of aerobic exercise to be boring or
discomforting. In support of these observations, it has been
reported that total body fat was inversely related to minutes
of vigorous physical activity per day in youth (54). Others
observed that this decline in physical activity may start early
in life in obese youth (103).
Recently, it has been suggested that resistance training may
offer observable health value to obese children and adoles-
cents (23,83,243). Obese youth tend to enjoy resistance
training because it is typically characterized by short periods
of physical activity interspersed with brief rest periods
between sets and exercises, which is more consistent with
how youth move and play (13,106). Several studies have
reported favorable changes in body composition in children
and adolescents who were obese or at risk for obesity after
participation in a resistance training program or a circuit
weight training (i.e., combined resistance and aerobic train-
ing) program (24,203,206,214,220,224,242,254). In a report,
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the level of adiposity in school-aged youth was a strong
negative predictor of the resistance training effect in the
lower limbs (93). Thus, obese youth may need a higher
relative training intensity to produce the desired effect.
Of interest, researchers found that participation in a 16-
week resistance training program significantly decreased
body fat and significantly increased insulin sensitivity in
adolescent males who were at risk for obesity (206). Because
the increase in insulin sensitively remained significant after
adjustment for changes in total fat mass and total lean mass, it
appeared that regular resistance training may have resulted in
qualitative changes in skeletal muscle that contributed
to enhanced insulin action. Compliance to this program
was impressive with 96% of the participants completing the
program. Other researchers identified muscular strength as
an independent and powerful predictor of better insulin
sensitivity in youth aged 10–15 years (21). Because resistance
training may provide a more enjoyable and sustainable
approach to health-related physical activity promotion in
children and adolescents who are obese or at risk for obesity,
additional randomized controlled trials are needed to further
examine the effects of resistance training on metabolic health
outcomes in youth.
At present, there is no clear association between regular
physical activity and reducing blood pressure in normotensive
youth, although limited data suggest that resistance training
may be an effective nonpharmacologic intervention in hyper-
tensive adolescents, provided that submaximal loads are used
and proper exercise procedures are followed (112). Others
have recommended low-intensity, high-repetition resistance
training for hypertensive adolescents who want to experience
this type of training (256). Although the acute blood pressure
response to resistance exercise is reportedly similar between
children and adults (172), blackouts (loss of consciousness)
and chronic hypertension, which have been reported in adult
competitive weightlifters (49), have not been reported in
children (88,187) or adolescents (112) after resistance training.
The effects of resistance training on blood lipoproteins in
youth are not well documented. Limited data suggest that
when compared with an inactive control group, resistance
training characterized by moderate loads and a high number
of repetitions can have a positive influence on the blood lipid
profile of children (220,247), and similar trends have been
observed in adolescents (98). Because changes in body
composition and nutritional intake may influence lipoprotein
concentrations in youth, a comprehensive health-enhancing
program that includes regular physical activity, behavioral
counseling, and nutrition education may be most effective for
improving the blood lipid profile in youth with dyslipidemia (7).
Bone Health. Despite traditional fears that resistance training
would be harmful to the immature skeletal of youth, current
observations suggest that childhood and adolescence may be
the opportune time for the bone modeling and remodeling
process to respond to the tensile and compressive forces
associated with weight-bearing activities (15,121,230,235).
Indeed, weight-bearing physical activity is essential for
normal bone formation and growth (148). If age-specific
resistance training guidelines are followed and if nutritional
recommendations (e.g., adequate calcium) are adhered to,
regular participation in a resistance training program can
maximize bone mineral density during childhood and adoles-
cence (230,235,238). Moreover, there is no detrimental effect
of resistance training on linear growth in children and
adolescents (91,147)
Results from several research studies indicate that regular
participation in sports and specialized fitness programs that
include resistance training can be a potent osteogenic
stimulus in youth (16,20,50,145,154,166,173,237,241). It has
been reported that adolescent weightlifters displayed levels
of bone mineral density (50) and bone mineral content (237)
well above values of age-matched controls. Other researchers
found that weightlifting can impart some benefit on bone
development in youth but not as much as year-round soccer
(20). The repetitive exposure to physical loading in sports
such as gymnastics has also resulted in significantly higher
bone mineral density in young athletes as compared with
age-matched controls (16,241).
In a study that provides direct evidence that high-impact
exercise enhances bone accrual in preadolescent girls,
participation in a 10-month physical activity program
(combined resistance training and aerobic exercise) resulted
in significant improvements in bone mineral density in the
exercise group as compared with the control group (166).
Likewise, preadolescent boys who performed a high-impact
circuit exercise program for 20 months had greater bone
expansion on both the periosteal and endosteal surfaces
(145). Others noted that a school-based physical activity
intervention that included plyometric training enhanced bone
mass at the weight-bearing proximal femur in children (154).
Although peak bone mass is influenced by genetics (43),
regular participation in high-strain-eliciting sports and
specialized exercise such as resistance training may have
a desirable influence on bone health in children and adoles-
cents. It appears that the osteogenic response to exercise in
youth can be enhanced by sensibly prescribing multi-joint,
moderate to high intensity resistance training exercises
(e.g., bench press, squat, and weightlifting movements) and
unaccustomed plyometric exercises (e.g., jumping and
hopping). Although additional clinical trials are needed to
more precisely define the exercise prescription, the impor-
tance of maintaining participation in sports and specialized
activities throughout life must not be overlooked because
training-induced improvements in bone health may be lost
over time if the program is not continued (110).
Psychosocial Health and Well-being. Data from adult studies
suggest that the effects of resistance training extend beyond
physical measures and include improvements in mental health
and well-being (157,228,229). Although it is reasonable to
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assume that similar findings would be observed in children
and adolescents who participate in a resistance training
program, caution is needed in extending observations to
younger populations because of the psychological immatu-
rity of youth as compared with adults. Limited evidence
suggests that resistance training may positively influence the
psychological well-being of children (123,253). Others noted
significant improvements in mood and self-appraisal factors
in children who participated in a physical activity program
that included resistance training and aerobic games (10).
Conversely, no significant changes in self-concept were
found in children after resistance training in other studies
(89,198), although initial scores in psychological measures
were relatively high in these reports. Although speculative,
the psychological benefits of resistance training may be most
apparent in youth who begin training with below average
measures of strength and psychosocial well-being.
Of interest, clinicians have noted that the socialization and
mental discipline exhibited by children who resistance trained
were similar to those exhibited by team sport participants
(187), and children’s attitudes toward physical education,
physical fitness, and lifelong exercise reportedly improved
after a conditioning program that included resistance training
(249,250). If appropriate resistance training guidelines are
followed and if children and adolescents are encouraged
to embrace self-improvement and feel good about their
performances, the positive psychosocial effects of resistance
training programs may indeed be comparable with other
sports and recreational activities. Conversely, intensive train-
ing, overzealous coaching, and excessive pressure to perform
at a level beyond one’s capabilities can have a negative effect
on some youth who are emotionally and psychologically
vulnerable (3,42). In some cases, inappropriate coaching
methods, unethical training practices, or an emphasis on
leanness may lead to the abuse of performance-enhancing
drugs (122), restrictive eating behaviors (171), or burnout
(overtraining syndrome) (32).
Motor Performance Skills and Sports Performance. Improvements
in selected motor performance skills (e.g., long jump, vertical
jump, sprint speed, and medicine ball toss) have been
observed in children and adolescents after resistance training
with weight machines, free weights, body weight strength
exercises, and medicine balls (77,92,96,118,144,221,246).
Gains in motor performance skills in youth have also been
noted after regular participation in plyometric training
programs (36,134,151,216). More recently, researchers have
reported that the combination of resistance training and
plyometric training may offer the most benefit for adolescent
athletes (75,143,168,202). As previously observed in adults
(2,95), the effects of resistance training and plyometric
training may actually be synergistic, with their combined
effects being greater than each program performed alone.
In contrast, other studies (80,88,96) reported significant
gains in strength without concomitant improvements in
selected motor performance skills after several weeks of
resistance training. Because the effects of resistance training
on motor performance are dependent on the design of the
training program, the principle of training specificity should
be considered when evaluating these data. As previously
observed in adult populations (97), training adaptations in
children and adolescents are rather specific to the movement
pattern, velocity of movement, contraction type, and con-
traction force (113,174). Thus, irrespective of age, resistance
training programs that include specific exercises (e.g.,
weightlifting movements and plyometrics) and types of
muscle actions in a manner that is specific for which training
is being performed are more likely to result in the greatest
improvements in motor skill performance.
Although the potential for resistance training to enhance
the sports performance of young athletes seems reasonable,
scientific evaluations of this observation are difficult because
athletic performance is such a multivariate outcome. Two
studies (26,37) reported favorable changes in swim perfor-
mance in age group swimmers, although one study found no
significant difference in freestyle turning performance in
adolescent swimmers who performed 15 minutes of plyo-
metric training for 20 weeks (51). In another report,
researchers found significant correlations between balance
and skating speed in junior ice hockey players younger than
19 years (19). Other studies involving young basketball and
soccer players have noted the importance of incorporating
some type of resistance training into sports training sessions
to maximize gains in strength and power in young athletes
(46,233). Although most published reports and anecdotal
comments from youth coaches suggest that regular partic-
ipation in a well-designed resistance training program will
result in some degree of improvement in athletic perfor-
mance (84,137,163), further research is still required in this
important field of study.
To date, there have not been any long-term investigations
studying the effects of a comprehensive youth resistance
training program on sports performance during the adult
years, although theoretical models highlighting the potential
benefits have been proposed (130). Nevertheless, based on
the available evidence, curtailment of sports practice and
competitions during the developmental years to allow time
for fitness conditioning that includes resistance training
seems reasonable, providing that the training program is
competently supervised, is progressive, and is of sufficient
duration and intensity. Because aspiring young athletes
cannot play themselves into shape, one of the greatest
benefits of youth resistance training may be its ability to
better prepare children and adolescents for successful and
enjoyable participation in athletic activities.
Sports-Related Injuries. The number of children and adoles-
cents in school-sponsored and community-based sports
programs continues to increase. However, along with this
increase in sports participation has come numerous reports of
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injuries to the ill-prepared or improperly trained young
athlete (3,40,64,162). Sports-related injuries have become
a significant cause of hospitalization and health care costs
during childhood and adolescence (162), and it is possible
that certain youth sport injuries can increase the risk of
osteoarthritis later in life (61). Sports-related injuries are also
one reason why some young athletes drop out of sports (109).
Although the total elimination of sports-related injuries is
an unrealistic goal, appropriately designed and sensibly
progressed fitness conditioning programs that include resis-
tance training may help reduce the likelihood of sports-
related injuries in young athletes (1,119,161,212). In a growing
number of cases, it seems that aspiring young athletes are ill
prepared for the demands of sports practice and competition
(64,162). By addressing the risk factors associated with youth
sport injuries (e.g., previous injury, poor conditioning, muscle
imbalances, and errors in training), it has been suggested that
both acute and overuse injuries could be reduced by 15–50%
(161). Although there are many mechanisms to potentially
reduce sports-related injuries in young athletes (e.g., coach-
ing education, safe equipment, proper nutrition), enhancing
physical fitness as a preventative health measure should
be considered a cornerstone of multicomponent treatment
programs.
Comprehensive conditioning programs that included re-
sistance training, plyometric training, or both have proven to
be an effective strategy for reducing sports-related injuries in
adolescent athletes (39,60,115,116,120,149,176), and it is
possible that similar effects would be observed in children,
although additional research is needed to support this
contention. Preseason conditioning programs that included
resistance training decreased the number and severity of
injuries in high school football players (39) and, similarly,
decreased the incidence of injury in adolescent soccer players
(115). Others observed that balance training (63,65) or
balance training and strengthening exercises (244,245) were
effective in reducing sports-related injuries in adolescent
athletes.
Because of the relatively high incidence of knee injuries in
young female athletes as compared with males (185),
researchers have investigated the effects of various training
programs on injury rates in young female subjects. Of note,
preseason conditioning programs that included plyometric
exercises, resistance training, and education on jumping
mechanics significantly reduced the number of serious knee
injuries in adolescent female athletes (120,149). Conversely,
no significant differences in injury rates were observed in
adolescent female athletes who participated in an in-season
plyometric training program (181) or structured warm-up
activities that included strength, balance, and agility exercises
(217). Differences in the design of the training programs and
time of implementation (i.e., preseason vs. in-season) could
explain, at least in part, these conflicting results.
Collectively, a majority of the evidence suggests that
regular participation in a preseason conditioning program
that includes plyometric exercises, resistance training, balance
skills, and education may reduce the likelihood of sports-
related injuries in young athletes. Yet some data suggest that
only a minority of young athletes participate in comprehen-
sive conditioning programs before sports participation (34).
Clearly, there is an ongoing need for school- or coach-
sponsored involvement to ensure that all young athletes
participate in multi-component conditioning programs
before sports training and competition.
However, the addition of preseason conditioning to the
total exercise dose, which includes free play as well as
organized sports, should be carefully considered because this
type of training adds to the chronic, repetitive stress placed on
the developing musculoskeletal system. Some young athletes
with relatively immature musculoskeletal systems may be
intolerant of the same exercise dose that the majority of the
athletes in the same program can tolerate. This biologic
uniqueness in growing athletes can result in stress fracture
syndromes manifested by a variety of conditions such as
traction apophysitis, injuries to the developing joint surfaces,
or injuries to the immature spine (3,159,177).
Because of the interindividual variability of stress tolerance,
each child must be treated as an individual and observed for
signs of incipient stress failure syndromes, which would
require a modification of the frequency, volume, intensity, and
progression of training. With the awareness of this variability
in children and adolescents of the same age to accept and
tolerate stress, many of these stress failure syndromes can be
prevented. In some instances, it may be necessary for young
athletes to reduce their sport involvement to allow time for
preparatory strength and conditioning with adequate rest and
recovery between training sessions. A reduction in per-
formance and an increased risk of injury can result by fre-
quent training sessions without adequate rest and recovery
in-between (99).
There is insufficient evidence to decide for or against
improvements in subjective ‘‘energy’’ level, sleep patterns,
emotional maturity, immune function, nutritional status, cog-
nitive performance, or health care utilization. It is probable
that either these characteristics would be favorably altered or
at least not unfavorably influenced by resistance training,
providing that the program is properly designed, pleasurable,
and rewarding.
Youth Resistance Training Guidelines
A prerequisite for the development and administration of safe,
effective, and enjoyable youth resistance training programs is
an understanding of established training principles and an
appreciation for the physical and psychosocial uniqueness of
children and adolescents. Although there is no minimum age
requirement at which children can begin resistance training,
all participants must be mentally and physically ready to
comply with coaching instructions and undergo the stress
of a training program. In general, if a child is ready for
participation in sport activities (generally age 7 or 8 years),
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then he or she is ready for some type of resistance training.
Although a medical examination before participation in
a youth resistance training program is not mandatory for
apparently healthy children, a medical examination is
recommended for youth with signs or symptoms suggestive
of disease and for youth with known disease.
Instruction and supervision should be provided by qualified
adults who have an understanding of youth resistance training
guidelines and who are knowledgeable of the physical and
psychosocial uniqueness of children and adolescents. More-
over, teachers, personal fitness trainers, and youth coaches
should develop an appropriate philosophy about training
youth that is consistent with the needs, goals, and interests of
children and adolescents. Ideally, adults who teach and coach
youth resistance training should have practical experience
working with children and adolescents, a recognized pro-
fessional certification (e.g., National Strength and Condition-
ing Association [NSCA] Certified Strength and Conditioning
Specialist or NSCA Certified Personal Trainer), and a level of
knowledge commensurate with a college degree in physical
education, exercise science, or a related field. For youths
participating in advanced training programs, coaches should
have additional knowledge and practical experience to
properly instruct and sensibly prescribe or advance this type
of training. Although less experienced supervisors may assist
in the organization and implementation of youth resistance
training programs, it is unlikely they will be able to provide the
quality of care and instruction needed for more advanced
training. If qualified supervision, age-appropriate exercise
equipment, and a safe training environment are not available,
youth should not perform resistance exercise due to the
increased risk of injury (107,132).
Basic education on weight room etiquette, proper exercise
technique, individual goals, and realistic outcomes should be
part of youth resistance training programs. All participants
should receive instruction on safety concerns including the
correct use of collars; appropriate spotting procedures;
the proper storage of exercise equipment; the appropriate
handling of barbells, dumbbells, and plates; and sensible
starting weights. This is particularly important for untrained
children who often overestimate their physical abilities (184)
and who may not be aware of the inherent risks associated
with resistance training exercise equipment. Instead of
competing against each other, youth should be encouraged
to embrace self-improvement and feel good about their
performances (e.g., the ability to correctly perform a multi-
joint lift). The importance of creating an enjoyable exercise
experience for all participants should not be overlooked
because enjoyment has been shown to mediate the effects of
youth physical activity programs (58). Adults should teach
youth about their bodies as well as the potential benefits of
a healthy lifestyle (e.g., proper nutrition, adequate sleep, stress
management, and regular physical activity) (129).
Qualified and enthusiastic instruction not only enhance
participant safety and enjoyment but also direct supervision of
youth resistance training programs can improve program
adherence and optimize strength gains (53). Although all
training sessions should be supervised by a qualified adult (or
several adults depending on class size), additional supervision
may be needed during the first few weeks of the resistance
training program when participants are learning proper
exercise technique and training procedures. Adults should
present information to children and adolescents in a style and
language that is appropriate for their level of understanding,
and positive, encouraging feedback should be used to foster
feelings of competence and reduce anxiety (188). All
participants should be encouraged to ask questions and
freely state their concerns about the program. Charts, posters,
and workout cards that promote proper exercise technique
and realistic expectations are helpful.
Various combinations of resistance training program
variables have proven to be safe and effective for children,
providing that program developers used scientific informa-
tion, established training principles, and common sense. All
youth resistance training programs should include instruction
on proper lifting techniques, safety procedures, and specific
methods of progression. Because the act of resistance training
itself does not ensure that optimal gains in strength and power
will be realized, the ideal approach is to incorporate resistance
training into a progressive conditioning program in which the
volume and intensity of training change throughout the year
(141). It is the systematic structuring of program variables
along with individual effort and qualified instruction that
will determine the outcomes associated with resistance
training. Finally, children and adolescents must not be treated
as miniature adults, nor should adult exercise guidelines and
training philosophies be imposed on youth.
The program variables that should be considered when
designing a youth resistance training program include (a)
warm-up and cool-down, (b) choice and order of exercise, (c)
training intensity and volume, (d) rest intervals between sets
and exercises, (e) repetition velocity, (f) training frequency,
and (g) program variation. Table 1 summarizes youth
resistance training guidelines. A more detailed description
of youth resistance program variables and training consid-
erations is available elsewhere (47,84,130,137,156,192).
Warm-up and Cool-down. Over the past few years, long-held
beliefs regarding the routine practice of warm-up static
stretching have been questioned (133,208,223). An acute bout
of static stretching has been found to have a negative impact
on strength and power performance in adults (208), and
similar findings have been reported in adolescents (155,257).
In recent times, there has been rising interest in warm-up
procedures that involve the performance of dynamic move-
ments (e.g., hops, skips, jumps, and movement-based
exercises for the upper and lower body) designed to elevate
core body temperature, enhance motor unit excitability,
improve kinesthetic awareness, and maximize active ranges
of motion (73,191). This type of dynamic warm-up may
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create an optimal environment for resistance training by
enhancing neuromuscular function (191,201). It has been
reported that warm-up protocols that include moderate to
high intensity dynamic movements can enhance power
performance in youth (68,71,76,209).
In the absence of sufficient evidence to endorse pre-event
static stretching with respect to performance enhancement,
the potential impact of pre-event dynamic exercise on
anaerobic fitness performance should be considered. In
addition to potential physiological benefits, a well-designed
dynamic warm-up can also set the tone for the training
session and establish a desired tempo for the upcoming
activities. A reasonable suggestion is to perform 5–10 minutes
of dynamic activities during the warm-up period and less
intense calisthenics and static stretching at the end of the
workout. A cool-down period consisting of general calis-
thenics and static stretching can help relax the body and
improve flexibility. Moreover, regular long-term stretching
(not performed during the warm-up) may improve perfor-
mance and mayreduce the risk ofinjury (208,218). During the
cool-down period, it is often worthwhile to reflect on what
each participant learned and review training objectives for
the next session.
Choice and Order of Exercise. Although a limitless number of
exercises can be used to enhance muscular fitness, it is
important to select exercises that are appropriate for a child’s
body size, fitness level, and exercise technique experience.
Also, the choice of exercises should promote muscle balance
across joints and between opposing muscle groups (e.g.,
quadriceps and hamstrings). Weight machines (both child
sized and adult sized) as well as free weights, elastic bands,
medicine balls, and body weight exercises have been used by
children and adolescents in clinical- and school-based
exercise programs. It is reasonable to start with relatively
simple exercises and gradually progress to more advanced
multi-joint movements as confidence and competence
improve. However, in some cases (e.g., weightlifting class),
it may be appropriate to start with multi-joint movements,
provided that light loads are used and the focus is on
enhancing fundamental movement patterns. Regardless of
the mode of exercise, the concentric and eccentric phases of
each lift should be performed in a controlled manner with
proper exercise technique.
There are many ways to arrange the sequence of exercises
in a resistance training session. Most youth will perform total
body workouts several times per week, which involve
multiple exercises stressing all major muscle groups each
session. In this type of workout, large muscle group exercises
should be performed before smaller muscle group exercises,
and multi-joint exercises should be performed before single-
joint exercises. It is also helpful to perform more challenging
exercises earlier in the workout when the neuromuscular
system is less fatigued. Thus, if a child is learning how to
perform a weightlifting movement or a plyometric exercise,
this type of exercise should be performed early in the training
session so that the child can practice the exercise without
undue fatigue.
Training Intensity and Volume. Training intensity typically
refers to the amount of resistance used for a specific exercise,
whereas training volume generally refers to the total amount
of work performed in a training session. Although both of
these program variables are significant, training intensity is
one of the more important factors in the design of a resistance
training program. However, to maximize gains in muscular
fitness and reduce the risk of injury, youth must first learn how
to perform each exercise correctly with a light load (e.g.,
TABLE 1. General youth resistance training guidelines.
Provide qualified instruction and supervision
Ensure the exercise environment is safe and free of hazards
Start each training session with a 5- to 10-minute dynamic warm-up period
Begin with relatively light loads and always focus on the correct exercise technique
Perform 1–3 sets of 6–15 repetitions on a variety of upper- and lower-body strength exercises
Include specific exercises that strengthen the abdominal and lower back region
Focus on symmetrical muscular development and appropriate muscle balance around joints
Perform 1–3 sets of 3–6 repetitions on a variety of upper- and lower-body power exercises
Sensibly progress the training program depending on needs, goals, and abilities
Increase the resistance gradually (5–10%) as strength improves
Cool-down with less intense calisthenics and static stretching
Listen to individual needs and concerns throughout each session
Begin resistance training 2–3 times per week on nonconsecutive days
Use individualized workout logs to monitor progress
Keep the program fresh and challenging by systematically varying the training program
Optimize performance and recovery with healthy nutrition, proper hydration, and adequate sleep
Support and encouragement from instructors and parents will help maintain interest
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unloaded barbell) and then gradually progress the training
intensity, or volume, or both, without compromising exercise
technique to lift heavier loads.
If 1RM tests are not performed, a simple approach may be
to first establish the repetition range and then by trial and
error determine the maximum load that can be handled for
the prescribed range. For example, a child or adolescent may
begin resistance training with 1 or 2 sets of 10–15 repetitions
with a relatively light or moderate load to develop proper
exercise technique. Depending on individuals’ needs, goals,
and abilities, over time the program can be progressed to
include additional sets with heavier loads (e.g., 6 to 10RM) on
large muscle group exercises to maximize gains in muscle
strength and power. Although additional training studies are
needed to explore the effects of different resistance training
programs on youth, multiple-set training protocols have
proven to be more effective than single-set protocols in adults
(136), and it is likely that similar findings would occur in
children and adolescents over the long-term.
With a careful prescription of sets and repetitions, the
training stimulus will remain effective and therefore the effort
to benefit ratio will be maximized. However, it is important to
realize that not all exercises need to be performed for the same
number of sets and repetitions. For example, an adolescent
with resistance training experience may perform 3 sets of 6–8
repetitions on multi-joint exercises (e.g., back squat and bench
press) with a relatively heavy weight and 2 sets of 10–12
repetitions on single-joint exercises (e.g., biceps curl and
triceps extension) with a relatively moderate weight. Of
interest, findings from adult studies indicate that the number
of repetitions that can be performed at a given percentage of
the 1RM is influenced by the amount of muscle mass used
during an exercise (207), and similar observations have been
reported in children (85).
Due to the relatively intense nature of power exercises
(e.g., plyometric or weightlifting movements), fewer than 6–8
repetitions per set are typically recommended for youth.
Unlike traditional strength-building exercises, power exer-
cises are explosive but highly controlled movements that
require a high degree of technical skill. Because fatigue can
influence the performance of power exercises, it is recom-
mended that youth perform fewer quality repetitions to
maintain movement speed and efficiency for all repetitions
within a set.
In an attempt to aid in the exercise prescription, researchers
have developed prediction equations based on repetitions
performed to fatigue with a submaximal load (124,142,152).
In general, it was found that 1RM strength on selected
exercises may be predicted with reasonable accuracy in
young male and female athletes. Others have developed
child-specific perceived exertion rating scales to assess the
exertional perceptions of children during resistance exercise
(78,193). Subjective information from these scales can be
used to assist in the prescription of effective youth resistance
training programs.
Rest Intervals Between Sets and Exercises. The length of the rest
interval between sets and exercises is a program variable
of primary importance to coaches, teachers, athletes, and
researchers (251). Because acute force and power production
may be compromised if the rest interval is too short, longer
rest intervals of at least 2–3 minutes for primary, multi-
ple-joint exercises are typically recommended during adult
resistance training programs (136). However, rest interval
recommendations for adults may not be consistent with the
needs and abilities of younger populations due to growth-
and maturation-related differences in response to physical
exertion. Studies have shown that children are able to recover
from high-intensity, short-term, intermittent exercise faster
than adults (82,90,255).
Although few data examining the effects of rest interval
length on strength performance in younger populations are
available, it appears that children and adolescents can resist
fatigue to a greater extent than adults during several repeated
sets of resistance exercise (82,213,255). Thus, a shorter rest
interval (about 1 minute) may suffice in children and adoles-
cents when performing a moderate-intensity resistance exer-
cise protocol, although the likelihood that adolescents may
fatigue more rapidly than children should be considered.
Obviously, training intensity, training volume, exercise
choice, and fitness level will influence the length of the rest
interval. Some young athletes (e.g., adolescent weightlifters)
who perform exercises that require higher levels of power or
skill may require longer rest intervals (e.g., 2–3 minutes)
between sets and trials during practice and competition to
maintain muscle performance.
Repetition Velocity. The velocity or cadence at which a strength
exercise is performed can affect the adaptations to a training
program (136). Because youth need to learn how to perform
each exercise correctly with a relatively light load, it is
generally recommended that youth resistance train in
a controlled manner at a moderate velocity. However,
different training velocities may be used depending on the
choice of exercise. For example, plyometric exercises and
weightlifting movements are explosive but highly controlled
movements that should be performed at a high velocity.
Although additional research is needed, it is likely that the
performance of different training velocities within a training
program may provide the most effective resistance training
stimulus.
Training Frequency. A resistance training frequency of 2–3
times per week on nonconsecutive days is recommended for
children and adolescents. Limited evidence indicates that
1dwk
21
of resistance training may be suboptimal for
enhancing muscular strength in youth (29,79), although once
per week training maybe effective in retaining the strength
gains made after resistance training (55). In general, a training
frequency of 2 or 3 times per week on nonconsecutive
days will allow for adequate recovery between sessions
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(48–72 hours between sessions) and will be effective for
enhancing strength and power in children and adolescents.
Although some young athletes may participate in strength
and conditioning activities more than 3 dwk
21
, factors such
as the training volume, training intensity, exercise selection,
nutritional intake, and sleep habits need to be considered as
these factors may influence one’s ability to recover from and
adapt to the training program. As training programs become
more advanced (and potentially more frequent), the
importance of reinforcing proper exercise technique and
training habits with less intense workouts during the week
should not be overlooked.
Program Variation. By periodically varying program variables,
long-term performance gains will be optimized, boredom will
be reduced, and the risk of overuse injuries will likely decrease
(136,138). The concept whereby a training program is
systematically varied over time is known as periodization. In
the long term, periodized resistance training programs (with
adequate recovery between training sessions) will allow
participants to make even greater gains because the body will
be challenged to adapt to even greater demands. Although
additional research involving younger populations is needed,
it is reasonable to suggest that children and adolescents who
participate in well-designed, periodized resistance training
programs and continue to improve their health and fitness
may be more likely to adhere to their exercise programs.
Furthermore, planned changes in the program variables can
help prevent training plateaus, which are not uncommon
after the first 8–12 weeks of resistance training.
Program variables for progression during youth resistance
training for strength and power are outlined in Table 2 and
Table 3, respectively. Regardless of the training goal, all youth
should begin with a light load and progress gradually to learn
proper exercise technique and become skilled in various
exercise procedures. Because both force and velocity
components are important for power training, 2 loading
strategies are required, namely, moderate to heavy loads for
strength and light to moderate loads performed at an
explosive lifting velocity. Although multi-joint exercises such
as power cleans and push presses have been used extensively
for power training, proper technique must be stressed
because the quality of effort per repetition (maximal velocity)
is critical to the performance of these lifts. A power
component for novice and intermediate lifters consisting of
1–3 sets of 3–6 repetitions performed not to failure should be
integrated into the resistance training program. Although
traditional repetition systems normally involve the perfor-
mance of successive repetitions with minimal pause in
between each repetition, the performance of explosive
movements does not always need to conform to this pattern.
Given the importance of learning proper exercise technique,
every repetition should be initiated from the proper starting
position. Hence, it may be advantageous for young
weightlifters to pause briefly between each repetition to
reset their starting position to ensure that optimal technique
is achieved on every repetition.
For the purpose of this review, a ‘‘novice’’ refers to an
individual who has no or limited resistance training
experience (#2 to 3 months) or an individual who has not
trained for several months. ‘‘Intermediate’’ refers to an
individual who has approximately 3–12 months of consistent
resistance training experience. ‘‘Advanced’’ refers to those
individuals with at least 12 months of resistance training
experience who also attained significant improvements in
muscular strength and power.
Although there is not one model of periodization, the
general concept is to prioritize training goals and then
develop a long-term plan that changes throughout the year.
By periodically varying the training intensity, training volume,
rest interval length, and exercise choice, the risk of over-
training may be minimized and potential for maintaining
training-induced gains could be maximized (99). It is worth
noting that periodized training programs should include
periods of active rest (e.g., 1–3 weeks recovery between sport
seasons) to allow for physical and psychological recovery
from the training sessions. This is particularly important for
youth who represent different sports teams, specialize in 1
TABLE 2. Recommendations for progression during resistance training for strength.*
Novice Intermediate Advanced
Muscle action ECC and CON ECC and CON ECC and CON
Exercise choice SJ and MJ SJ and MJ SJ and MJ
Intensity 50–70% 1RM 60–80% 1RM 70–85% 1RM
Volume 1–2 sets 310–15 reps 2–3 sets 38–12 reps $3 sets 36–10 reps
Rest intervals (min) 1 1–2 2–3
Velocity Moderate Moderate Moderate
Frequency (dwk
21
) 2–3 2–3 3–4
*ECC = eccentric; CON = concentric; SJ = single joint; MJ = multi-joint; 1RM = 1 repetition maximum; rep = repetition.
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sport year-round, or participate in extracurricular condition-
ing activities at private training centers. In addition, to
promote long-term gains in strength and performance in
children and adolescents, training programs should include
educational sessions on lifestyle factors and behaviors that
are conductive to high performance (129). Of note, the
importance of proper nutrition (52), sufficient hydration (44),
and adequate sleep (165) should not be overlooked. A
detailed review of periodization and lifestyle factors that may
influence athletic performance are beyond the scope of this
review, but they are available elsewhere (129,136,138).
CONCLUSIONS
Despite outdated concerns regarding the safety or effective-
ness of youth resistance training, scientific evidence and
clinical impressions indicate that youth resistance training has
the potential to offer observable health and fitness value to
children and adolescents, provided that appropriate training
guidelines are followed and qualified instruction is available.
In addition to performance-related benefits, the effects of
resistance training on selected health-related measures
including bone health, body composition, and sports injury
reduction should be recognized by teachers, coaches, parents,
and health care providers. These health benefits can be safely
obtained by most children and adolescents when prescribed
age-appropriate resistance training guidelines.
We now have the information to support the consideration
of incorporating resistance training into a health-oriented
approach to lifelong physical activity. Important future
research goals should be to elucidate the mechanisms
responsible for the health-related benefits associated with
youth resistance exercise, to establish the combination of
program variables that may optimize long-term training
adaptations and exercise adherence in children and adoles-
cents, and to explore the potential benefits of resistance
training on youth with various medical conditions including
obesity, diabetes, cancer, severe burns, and physical limita-
tions, and intellectual disabilities.
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