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Summary
P
hysical fitness is a state of being that reflects a person's ability to
perform specific exercises or functions, and is related to present and
future health outcomes. In the United States, serious efforts to assess
the physical fitness of youth with a battery of tests began in the 19th cen-
tury. These efforts intensified during times of war, focused primarily on
improving athletic performance and military preparedness. Over time, the
focus of such surveys shifted to assessing health rather than performance,
reflecting growing concern about the current and future health of the
nation's youth. While measures of performance-related fitness are designed
to evaluate a person's capability to carry out certain physical tasks or activi-
ties, the focus of health-related fitness testing is on the concurrent or future
health status of the subject under assessment.
The first U.S. national survey of youth fitness in 1958 was followed
by surveys in 1965 and 1975 and then in 1985-1986. States and schools
have continued to assess fitness in youth during the past two decades; after
the 1985-1986 survey, however, there was no national-level assessment
of youth fitness until 2012, as part of the National Health and Nutrition
Examination Survey. Several factors may account for this gap, including the
fact that interest and effort have been directed more toward understanding
the role of physical activity in youth. This shift and the challenges inherent
in associating fitness in youth with health have resulted in few advances in
our understanding of the physiology and outcomes of fitness.
Assessment of fitness historically has encompassed such components as
body composition, cardiorespiratory endurance, musculoskeletal strength
and endurance, and flexibility. Examples of tests used historically in national
1
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2 FITNESS MEASURES AND HEALTH OUTCOMES IN YOUTH
surveys and schools are the progressive shuttle run and mile run tests for
cardiovascular endurance, measurement of body mass index (BMI) for
assessment of body composition, the curl-up and push-up tests for muscular
endurance, and the sit-and-reach tests for flexibility.
While the components of fitness measured and the specific test items
included in protocols have varied considerably across test batteries and
over time, youth fitness testing has become a well-established institution
in school physical education programs during the past half-century. In a
school context, tests are being used as institutional fitness assessment tools,
as educational tools to teach youth and their families about the importance
of physical fitness, and as communication tools to guide individuals on
attainable goals for maintaining fitness and health. These efforts are costly
in terms of not only human capacity and financial resources, but also the
extensive training and organizational and communication skills required for
their implementation. Most important, it is essential to use appropriate tests
and understand the results in a health context to minimize misclassification
and stigmatization of youth. Selection of the best tests is therefore a crucial
process, and knowledge gaps in this area were an important motivator of
the present study.
This study was undertaken in light of the past challenges encountered
in identifying fitness tests related to health in youth, spurred by a renewed
interest in fitness as one of the key tenets of health.
STUDY APPROACH
Given the gaps in knowledge noted above, the Institute of Medicine
(IOM) convened an 11-member committee with expertise in fitness mea-
sures, body composition and maturity, physical activity, physical education,
the development of cut-points (cutoff scores), motor development and skill,
and modifiers of fitness to conduct this study. The committee was asked to
assess the relationships between fitness tests and health outcomes in youth
based on a review of the literature designed and conducted by the Centers
for Disease Control and Prevention (CDC) (the committee's statement of
task is shown in Box S-1). The CDC search criteria included longitudinal,
experimental study designs in which fitness and health were measured in
healthy1 children aged 5-18 during 2000-2010. The CDC searches were
conducted specifically for the fitness components cardiorespiratory endur-
1The criteria included overweight and obese youth, but excluded youth with various dis-
abilities or congenital diseases. Since the primary task for this study was to identify fitness tests
appropriate for a national youth fitness survey of the general youth population, the commit-
tee did not review additional literature specific to populations with disabilities, such as those
with cognitive or physical impairments, activity limitations, or participation restrictions (as
defined in Appendix B).
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SUMMARY 3
BOX S-1
Statement of Task
An ad hoc committee will recommend physical fitness test items for
assessment of youth fitness components that are associated with health
outcomes. The recommended items will be suitable for inclusion in a
national survey of fitness in children and youth. The committee will make
use of a systematic review of the literature conducted by the Centers for
Disease Control and Prevention. In examining the review, the commit-
tee will evaluate the relationships between the fitness components and
health outcomes (e.g., cardiovascular disease risk factors, musculosk-
eletal health, diabetes, obesity and others). Further, for selected fitness
components the committee will examine the relationships between per-
formance on specific test items and health outcomes.
In addition to the primary task above, the committee will answer the
following questions:
1.For recommended test items for which there is evidence of an
association with health, how should performance for the test
items be interpreted? Should the interpretation be based on a
cut-point approach? Are there alternative approaches to interpret
performance?
2.If the association between a particular test and health outcomes
reveals no obvious relationship to health, what strategy is most
appropriate for identifying a criterion-referenced standard? In such
a case, the committee may consider the use of norm-referenced
standards.
3.How do demographic characteristics and overweight and obesity
affect the tests scores and subsequent evaluations?
4.What additional research is needed to augment the evidence (or
lack thereof) about the associations between fitness measures and
health outcomes?
The committee will also study to what extent is change in perfor-
mance on a fitness test item (e.g., handgrip strength or 1.5-mile walk/run)
associated with change in health outcomes in youth who are apparently
"healthy" but include both obese and nonobese. In addition, the com-
mittee will identify the strengths and weaknesses of fitness test items
in regards to their practicality and as indicators of health outcomes in a
school setting and, based on practicality, will provide recommendations
for the most appropriate measures for each fitness component.
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4 FITNESS MEASURES AND HEALTH OUTCOMES IN YOUTH
ance and musculoskeletal strength and endurance. The relationship of
body composition measures to health is well established, so a systematic
review of their relationship to health was not conducted. Although time
and resources did not allow for a systematic review of the flexibility com-
ponent, the committee evaluated the relationships between flexibility and
health outcomes in studies from the CDC review that included a flexibility
measure.
To guide its review and deliberations, the committee created a concep-
tual framework that depicts the potential relationships between physical
fitness components and health as they are modified by various factors, such
as demographic characteristics, maturity status, motor skills, and genetics. In
addition to this conceptual framework, the committee developed the follow-
ing set of general criteria for selecting tests to be implemented in the field:
· identification of a relationship between a fitness component and
health markers;
· evaluation of the quality of the studies and the strength of the
evidence for a relationship between fitness test items and health
markers in youth, based on the CDC's systematic review;
· identification of health-related test items;
· evaluation of the integrity of test items (i.e., validity and reliability);
and
· evaluation of the feasibility of implementing test items.
In its statement of task, the committee was asked not only to select
test items for a national fitness survey but also to consider the practicality
of their implementation. The committee reviewed only the evidence for
field-based methods because, even if they are more prone to error than
laboratory methods, they require less highly specialized training and are
conducted with mobile equipment, adequate for assessing large samples of
youth. The committee also recognized that national surveys and schools
and other educational settings2 raise different implementation issues. In
addition, the conduct of fitness tests in schools may be driven by goals
beyond health, such as educating about the importance of specific fitness
components. Because of their role as educational tools, certain test items
will be beneficial in a school fitness test battery even if their relationship
to health cannot as yet be confirmed in youth. Therefore, the committee
developed separate sets of recommendations for these two settings.
Implementing the best health-related fitness items entails important
steps that relate to the interpretation and communication of the test results
in a health context. Identifying one or more health outcomes that are
2Other educational settings include, for example, gymnasiums and fitness centers.
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SUMMARY 5
related to the test items of interest, then, is essential. Equally important is
understanding the relationship between the test items and the associated
health outcomes in quantitative terms so the results can be interpreted in
a health context. For this purpose, a criterion-referenced cut-point--a test
performance score below (or above) which a risk to health may exist--can
be used. Ideally, criterion-referenced cut-points would be derived from
population-based data on the relationship between a fitness test and a
health outcome or marker in youth. As noted earlier, however, data on the
relationship between fitness and health in youth are limited, mainly because
of the difficulty of identifying such associations when health constructs in
youth are not well defined. When data in youth populations are not avail-
able, alternative approaches can be followed to derive cut-points (interim
cut-points). Box S-2 provides the committee's guidance on methods for
selecting criterion-referenced cut-points and interim cut-points for health-
related fitness testing in youth.
CONCLUSIONS AND RECOMMENDATIONS
The committee developed conclusions and recommendations regard-
ing fitness measures for youth for each of four components of fitness:
body composition, cardiorespiratory endurance, musculoskeletal fitness,
and flexibility. For each of these components, the committee identified test
items, reviewed the evidence on these items, applied the general criteria for
selection listed earlier, considered modifying factors, assessed the feasibil-
ity of implementation, and applied the guidance in Box S-2 for selecting
cut-points. In general, the studies reviewed provided insufficient data with
which to assess the influence of several potential modifiers--age, gender,
race/ethnicity, body composition, maturation status, motor skill--on per-
formance on tests of cardiorespiratory endurance, musculoskeletal fitness,
and flexibility.
As noted earlier, the committee's recommendations are specific to the
implementation of fitness measures either in a national youth fitness survey
or in schools and other educational settings. The recommended tests for
a national youth fitness survey represent valid, reliable, feasible, and safe
tests for the assessment of health-related fitness in youth for population-
level health-monitoring purposes. National survey fitness tests are intended
to be implemented by skilled national administrators of such surveys (i.e.,
those familiar with the procedures for conducting large surveys and the
protocols for fitness tests) in school settings. For schools, recommendations
are made for fitness tests that are low in cost and equipment requirements
such that they are practical for school-based implementation. Regardless of
the setting, test administrators and those interpreting and communicating
the results should receive appropriate training in conducting and interpret-
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6 FITNESS MEASURES AND HEALTH OUTCOMES IN YOUTH
BOX S-2
Guidance for Developing Cut-Points
The committee determined that a criterion-referenced method should
be employed in developing cut-points. That is, a test taker's performance
should be compared against an absolute criterion that is related to
health. The following are options, depending on the available evidence:
· W
hen a confirmed concurrent relationship exists between health
outcome measures and fitness tests in youth, criterion-referenced
cut-points can be determined by using a data-mining procedure
that establishes the statistical evidence for that relationship.
· When a confirmed concurrent relationship exists only in adults but
not in youth, either a relative position or a panel-driven method can
be used, whereby interim criterion-referenced cut-points in youth
are derived from the percentile values (related to health outcomes)
extrapolated from the adult population or by a panel of experts
using cut-points for adults and other available information (e.g.,
growth curves and performance characteristics for different ages
and genders).
· When no confirmed relationship exists in either youth or adults, a
comparatively relative position method can be employed, whereby
interim criterion-referenced cut-points are derived from the per-
centile values (related to health outcomes) extrapolated from a
different test. When the percentile from another test is used, the
two tests should be as comparable as possible in their nature (e.g.,
both require movement of the body) and in the dimension they
measure (e.g., upper-body strength).
ing the tests to minimize measurement and classification errors and prevent
adverse events. Finally, the committee offers recommendations for future
research that would advance understanding of youth fitness measures and
their association with health outcomes.
Conclusions About Components of Fitness
The committee's conclusions relate to the four components of fitness
detailed above: body composition, cardiorespiratory endurance, musculo-
skeletal fitness, and flexibility.
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SUMMARY 7
Body Composition
Body composition denotes the sum of the basic components that make
up body weight, including fat, muscle, and bone content. The committee
defined body composition operationally as a component of fitness, a health
marker, and a modifier of fitness. Field-based measures of body composi-
tion relate to different dimensions. For example, skinfold is an indicator of
subcutaneous fat, whereas waist circumference is an indicator of abdominal
adiposity, and BMI measures body weight-for-height. These measures also
vary in that they have been associated with different health markers; for
example, skinfold measures are related to risk factors for cardiovascular
disease and metabolic syndrome, waist circumference has been associated
with cardiovascular disease, and BMI is related to risk of diabetes and
hypertension. When implementing and interpreting measures of body com-
position, it is important to note that many factors, such as physical activ-
ity, calorie consumption, age, and maturation, influence body composition
measures. The committee selected measures of body composition based on
their relationship to health markers, their integrity, and their feasibility.
The committee concluded that the above three measures of body com-
position--skinfold, waist circumference, and BMI--are important to collect
in a national youth fitness survey. Each is a proximal estimation of body fat
and has increased standard of error over laboratory measures. Moreover,
the measurement of body composition is multidimensional; no single mea-
sure is considered representative of all body composition tenets for youth
of all morphologies.
In selecting measures of body composition, some feasibility factors
must be considered: the availability of administrators with the highly spe-
cialized training required and the accessibility of appropriate space in which
to conduct the test. The reliability of skinfold and waist circumference
measurements depends on the skill of the test administrator; to avoid the
introduction of errors in the measurements, specific and intense training
is required. Training is also required to minimize concerns related to pri-
vacy in the administration of these measures. Also to ensure privacy, the
appropriate space should be available for conducting the tests. Given the
challenges associated with avoiding measurement errors, maintaining good
reliability, and ensuring privacy in the administration of skinfold and waist
circumference measurements, only BMI measurement is recommended for
administration in schools.
Cardiorespiratory Endurance
Cardiorespiratory endurance is the ability to perform large-muscle,
whole-body exercise at moderate to high intensity for an extended period
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8 FITNESS MEASURES AND HEALTH OUTCOMES IN YOUTH
of time. There is a well-established association between cardiorespiratory
endurance and health outcomes in adults and health markers or risk factors
in children--in particular, body weight, body composition, cardiometabolic
risk factors, blood pressure, cognitive function, and pulmonary function.
Although the fitness tests and protocols used vary substantially, the cardio-
respiratory endurance tests associated most frequently and strongly with a
positive change in health markers or risk factors are heart rate extrapolation
tests (i.e., those that use a treadmill or cycle ergometer and measure car-
diorespiratory endurance as maximal oxygen consumption [VO2max]) and
the progressive shuttle run. The health markers most frequently assessed
are related to body weight or adiposity and cardiometabolic risk factors.
The heart rate extrapolation and progressive shuttle run tests have high
validity and reliability. In terms of feasibility, the progressive shuttle run
is advantageous when time and financial constraints exist with respect to
the necessary training and equipment. Treadmill and cycle ergometer tests
are valid and reliable alternatives for a national survey in which space
limitations are a concern, but extensive training is feasible. The validity
and reliability of distance runs are more variable and in general lower than
has been reported for the heart rate extrapolation and progressive shuttle
run methods; however, these tests are appropriate for a school setting for
practical reasons.
Musculoskeletal Fitness
Musculoskeletal fitness is a multidimensional construct that encom-
passes three related components: muscle strength (the ability of skeletal
muscle to produce force under controlled conditions), muscle endurance
(the ability of skeletal muscle to perform repeated contractions against a
load), and muscle power (the peak force of a skeletal muscle multiplied by
the velocity of the muscle contraction). Neither any of these components
individually nor any single test can describe overall musculoskeletal fitness.
Therefore, a number of tests that measure various dimensions of musculo-
skeletal fitness often are used in combination. As with other fitness compo-
nents, a wide variety of tests, such as the curl-up, the push-up, the handgrip,
and jumps, have been used to measure musculoskeletal fitness in the past.
The committee concluded that adequate experimental and prospective
longitudinal evidence supports the relationship between the multidimen-
sional construct of musculoskeletal fitness and health. Empirical evidence
also is increasing for the importance of musculoskeletal fitness, especially
muscle strength and power, to health outcomes in adults. There is, however,
insufficient high-quality evidence to support a strong association between
any single musculoskeletal fitness test item and health markers in youth.
Based predominantly on evidence indicating a relationship to health out-
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SUMMARY 9
comes in adults, the committee concluded that musculoskeletal fitness
should be assessed in a national youth fitness survey.
Growing evidence supports use of the handgrip strength test and the
standing long jump as health-related musculoskeletal fitness test items in
youth. Studies reviewed show a relationship between performance on these
tests and bone health and body composition. The handgrip strength test
demonstrates moderate to strong validity when assessed against upper-
and lower-body criterion muscle strength measures. The standing long
jump, although not strictly a measure of muscle strength, demonstrates
acceptable validity against lower- and upper-body criterion muscle strength
measures and lower-body muscle power measures. The handgrip strength
and standing long jump tests demonstrate strong and moderate reliability,
respectively. The committee recommends that the handgrip strength and
standing long jump tests be included in a national survey. While these tests
should not be interpreted in a health context until their relationships with
health outcomes have been established more firmly in youth, they can be
included for their educational value. Other measures of muscular strength,
such as the modified pull-up or push-up as an alternative for measuring
upper-body musculoskeletal strength and power or the curl-up for measur-
ing core strength and endurance, also can be used in schools.
Flexibility
Flexibility is the intrinsic property of body tissues, including muscle and
connective tissue, that determines the range of motion achievable without
injury at a joint or group of joints. Like musculoskeletal fitness, flexibility is
specific; a person can have a good range of motion around a shoulder joint,
for example, but lack range of motion in the hip. Such specificity precludes
any relationship between a given measure of flexibility and any systemic
health markers (e.g., back pain, risk of injury, posture problems). Moreover,
clinical theory suggests that the complex interaction among multiple mus-
culoskeletal components (e.g., flexibility, strength, endurance), rather than
one component alone, is most likely to be associated with health markers
or outcomes. Further, possible associations with health are complicated by
the fact that risk may be higher for those with low or exceptionally high
flexibility than for those in the middle ranges. Finally, although evidence
suggests a link between flexibility and health among adults (e.g., low-back
pain), such evidence is more difficult to establish in youth given that the
commonly used health risk outcomes may take years to manifest.
The literature review did not reveal a relationship between any flexibil-
ity test and health in youth. In addition to the challenges mentioned above,
this could be due to the study designs included in this review. Specifically,
in contrast to studies on other fitness components, there was a lack of high-
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10 FITNESS MEASURES AND HEALTH OUTCOMES IN YOUTH
quality longitudinal and experimental studies measuring the association
between flexibility and health markers in youth. For example, many studies
did not include health markers hypothesized to be related to flexibility and
typically did not include a control. Future efforts to study the relationship
of flexibility to health will require a multivariate approach. Although no
relationship to health has been shown, the sit-and-reach test is feasible to
implement and has acceptable validity and reliability.
Recommendations for National Surveys
A substantial body of evidence supports the idea that specific tests
measuring cardiorespiratory endurance and body composition are related
to health markers in youth. The evidence for an association between mus-
culoskeletal fitness and health markers in youth is less extensive. The com-
mittee concluded that insufficient evidence has thus far been accumulated
to support recommending a health-related measure of flexibility for youth
at this time.
The committee concluded that a criterion-referenced approach using
cut-points associated with health markers is the ideal approach for inter-
preting scores. There is, however, insufficient evidence with which to
develop age- and gender-specific criterion-referenced cut-points for all
measures except for BMI. Until data are collected with which to establish
criterion-referenced cut-points, age- and gender-specific interim cut-points
corresponding to percentiles for adults on tests related to the same com-
ponent or for youth on tests related to a different or the same component
should be used.
RECOMMENDATION 8-1.3 A national survey of health-related
physical fitness in youth should include measures of cardiorespiratory
endurance, body composition, and musculoskeletal fitness. The survey
should include the following fitness test items: (1) measures of BMI,
waist circumference, and skinfold thickness (triceps and subscapular
sites) to assess body composition; (2) a progressive shuttle run, such as
the 20-meter shuttle run (or a submaximal treadmill or cycle ergom-
eter test if there are space limitations) to measure cardiorespiratory
endurance; and (3) handgrip strength and standing long jump tests to
measure musculoskeletal fitness.
RECOMMENDATION 8-2. Standard protocols for the administration
of measures of youth fitness in national surveys should be developed
3The committee's recommendations are numbered according to the chapter of the main
text in which they appear.
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SUMMARY 11
and implemented. The focus should be on maximizing the measures'
reliability, validity, and safety. Trained personnel should be used for test
administration and data collection.
RECOMMENDATION 8-3. Developers of fitness test batteries should
use age- and sex-specific cut-points to determine which individuals are
at risk of poor fitness-related health outcomes. Optimum cut-points
should be based on criterion values when population-based evidence
is available on the relationship between the level of performance on
a fitness test and a health outcome or marker. In the absence of cri-
terion values, interim population-based percentile values should be
applied. These values might be derived from adults on tests for the
same component or from youth on tests for a different or the same
component. Specifically, the guidance of the committee should be
applied as follows:
· ody composition: For BMI, the CDC-established cut-points
B
for underweight, overweight, and obesity evaluations should
be used. Interim cut-points for skinfold and waist circumfer-
ence measures could be derived from the CDC-established
percentiles for BMI.
· Cardiorespiratory endurance: For measures of cardiorespira-
tory endurance, interim cut-points could be derived from the
lowest performers (e.g., 20th percentile) on the cardiorespira-
tory endurance distribution curve.
· Musculoskeletal fitness: For musculoskeletal fitness tests, interim
cut-points could be derived by borrowing the percentile (e.g.,
20th percentile) from the cardiorespiratory endurance tests.
Recommendations for Schools and Other Educational Settings
The preceding recommendations outline the optimum test items for
measuring fitness in youth in national surveys. Conducting fitness tests in
educational settings can yield further benefits, such as contributing to the
body of evidence on the association between health-related fitness compo-
nents and learning outcomes, improving individuals' fitness performance,
and educating about the importance of physical fitness. The committee
considered the strengths and weaknesses of the test items recommended
for a national survey with regard to their practicality in schools and other
educational settings.
School leaders and teachers should apply the following recommenda-
tion and select applicable test items in light of the contextual variables that
characterize their schools, such as available equipment, space, and test
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12 FITNESS MEASURES AND HEALTH OUTCOMES IN YOUTH
administrators, as well as cost, as schools differ greatly on these variables.
Factors related to culture and race/ethnicity, as well as how a test item
aligns with the existing curriculum, should also be considered. Finally, per-
haps the most important element of fitness testing in schools is the interpre-
tation and dissemination of results. This element represents an opportunity
to assist participants in preventing disease and understanding fitness, but
can have detrimental effects on the individuals involved if not carried out
appropriately. As mentioned above, training in the administration of pro-
tocols and the interpretation and communication of test results is essential.
RECOMMENDATION 9-1. Developers and administrators of fitness
test batteries in schools and other educational settings should consider
including the following test items:
· tanding height (measure of linear growth status) and weight
s
(measure of body mass) to calculate BMI as an indicator of
body composition;
· a progressive shuttle run, such as the 20-meter shuttle run, to
measure cardiorespiratory endurance; and
· handgrip strength and standing long jump tests to measure
upper- and lower-body musculoskeletal strength and power,
respectively.
Additional tests that have not yet been shown to be related to health
but that are valid, reliable, and feasible may also be considered as supple-
mental educational tools. For cardiorespiratory endurance, alternatives to
the shuttle run include distance and/or timed runs, such as the 9-minute or
1-mile run, while the modified pull-up and push-up are possible alterna-
tives for measuring upper-body musculoskeletal strength. The curl-up may
be considered in addition to the suggested musculoskeletal fitness tests
for measuring core strength and endurance. Although the committee does
not recommend a flexibility measure as a core component of a fitness test
battery, administrators in schools and other educational settings may wish
to include the sit-and-reach test or its alternatives (e.g., backsaver sit-and-
reach) to measure flexibility. Experts who establish cut-points for inter-
preting performance on these fitness test items should follow the guidance
provided earlier (Box S-2 and Recommendation 8-3).
Recommendations for Future Research
Altogether, the CDC's literature review revealed many gaps in under-
standing of the relationship between fitness measures and health in youth.
Although the review revealed a number of associations between the two,
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SUMMARY 13
many of the studies reviewed were not designed to assess the independent
association between performance on a fitness test and a health outcome or
marker. Moreover, while not included in the search strategy, studies predict-
ing health outcomes in adulthood would be valuable in characterizing the
importance of a health marker. For example, it remains to be determined
whether changes in muscle strength and power during youth are predictive
of health outcomes in later life.
The committee offers the following recommendations for designing and
conducting research on some of the most pressing questions that must be
answered if progress is to continue in selecting the best measures of fitness
in youth. It should be noted that the committee is recommending research
only for those test items that have been studied well enough to justify their
inclusion here. At the same time, it is not the intent of the committee to
eliminate from future consideration those test items that currently do not
meet the level of evidence necessary for inclusion in a battery of tests.
RECOMMENDATION 10-1. Well-designed research studies aimed at
advancing understanding of the associations between fitness compo-
nents and health in youth should be undertaken. Researchers should
ensure that the interventions studied are both specific and sufficient
(i.e., appropriate dosage and duration) to induce a change in fitness.
In addition, studies should be designed so that the effect of potential
confounders (e.g., nutrition, physical activity, demographic variables,
maturity status) and the potential for adverse events can be analyzed.
RECOMMENDATION 10-2. Longitudinal studies should be con-
ducted to provide empirical evidence concerning how health markers
related to fitness track from youth into adulthood.
RECOMMENDATION 10-3. Randomized controlled trials and longi-
tudinal studies should be undertaken to understand the following issues
regarding the relationships between (1) specific fitness tests and health,
and (2) fitness components and health:
· tudies should explore the relationship between body composi-
S
tion measures and physical fitness tests and the potential interac-
tions among body composition, fitness, and health in youth.
· Studies should examine the relationship between changes in
cardiorespiratory endurance as measured by field tests, includ-
ing the shuttle run and timed and distance runs, and subse-
quent changes in health risk factors in youth beyond weight
status and cardiometabolic risk factors. Examples include bone
health and neurocognitive function and behavior.
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14 FITNESS MEASURES AND HEALTH OUTCOMES IN YOUTH
· tudies should address the relationship between specific mus-
S
culoskeletal fitness test items and health markers in youth.
Priority should be given to test items for which there is growing
evidence, such as the handgrip strength or standing long jump
test, or others that are promising. Since musculoskeletal fitness
is a multivariate construct, the studies should be designed so
that a variety of tests are conducted.
· Studies should investigate the relationship between specific
flexibility test items (e.g., sit-and-reach and its modifications),
either by themselves or in combination with musculoskeletal
fitness test items, and potential health markers (e.g., back pain,
posture, injury prevention). Such studies should include stretch-
ing interventions specifically designed to produce changes in
joint-specific flexibility. Since flexibility is a multivariate con-
struct, the studies should be designed so that a variety of tests
are conducted. Researchers should investigate the develop-
ment and validation of a general marker of musculoskeletal
systemic flexibility and its relationship to health markers and
risk factors.
· Studies should examine the potential effects of modifying fac-
tors (i.e., age, gender, race/ethnicity, body composition, matu-
rity status, training status/practice, motor skill, socioeconomic
factors) on fitness components and on the relationship between
a change in a health-related fitness component and health
markers in specific populations.
RECOMMENDATION 10-4. Developers of national surveys of
health-related physical fitness in youth should consider the inclusion
of measures of cardiometabolic health, bone health, and neurocogni-
tive function. The collection of fitness and health data in the same
individuals would allow investigators to further confirm whether direct
relationships between specific test items and health markers and risk
factors exist.
RECOMMENDATION 10-5. When an association between a fitness
test and a health marker is confirmed, research should be conducted to
establish and validate health-related cut-points for that test. For exam-
ple, given the association of skinfold measures with health markers,
large national studies should be conducted to establish health-related
cut-points for skinfold measures in youth.
