Medical
History
Associated
with Adolescent
Powerlifting
Eugene
W. Brown,
PhD,
and
Richard
G. Kimball
From the Youth Sports Institute, Department of Health and Physical Education, Michigan State University, East Lansing
ABSTRACT. A questionnaire, designed to elicit informa-tion about the training, experience, and medical history of adolescent powerlifters, was administered to 71 con-testants entered in the 1981 Michigan Teenage Power-lifting Championship. The average subject had partici-pated in 4.1 workouts per week for 17.1 months. Each workout lasted an average of 99.2 minutes. The popula-tion sustained 98 powerlifting injuries which caused a
discontinuance of training for a total of 1,126 days. The incidence and severity of pain in 13 regions of the body, as well as the site and type of powerlifting injury, were
investigated. The low back region was shown to be the site with the greatest number of injuries (49). This region also had the highest percent of subjects recording an elevated occurrence and level of pain associated with powenlifting. Pediatrics 1983;72:636-644; injuries, athletic
injuries, sports medicine, weight lifting.
Powerlifting is a form of competitive weight lift-ing. It consists of three events (Fig 1): squat lift, dead lift, and bench press. The goal of competitive
powerlifters is to lift their maximum amount in
each event. Competition in this sport is sanctioned
by the International Powerlifting Federation for
various age categories, which includes a 14 through
19 year grouping.
The extent and intensity of adolescent
involve-ment in powerlifting is unknown. The fact that
heavy weights can be lifted without excessive
atten-tion to technique may be a factor that attracts
adolescent weight lifters to this sport. Figures on
the number of adolescents competing are not
read-ily available. Many adolescents, other than
corn-Received for publication July 23, 1982; accepted Jan 27, 1983. Reprint requests to (E.W.B.) Youth Sports Institute, Depart-ment of Health and Physical Education, Michigan State Uni-versity, East Lansing, MI 48824.
PEDIATRICS (ISSN 0031 4005). Copyright © 1983 by the
American Academy of Pediatrics.
petitive powerlifters, also engage in the three lifts.
This is exemplified by the inclusion of powerlifting exercises in the weight training programs of high
school sports teams. By definition, weight training
involves repetitive lifting of submaximal loads
us-ing many different exercises for total body
condi-tioning. However, the percent of maximum weight lifted and the number of repetitions typically
per-formed by the adolescent athlete using powerlifts
as part of a weight training program is unknown. In teenage powerlifting, it is common for the
musculoskeletal system to be exposed to loads that
exceed body weight by as much as two to three
times (Table 1). In order for the body to support these loads, opposing muscular torques (joint
turn-ing forces) must be exerted which are at least equal
to the resistive torques resulting from the load and the weight of contributing body segments.
Extensors of the spine, hip, knee, and ankle are the primary muscle groups that provide opposing muscular torque in the squat and dead lift to
pre-vent the body from collapsing from the load. The squat lift is performed basically like a deep knee bend. According to the rules of the International
Powerlifting Federation, “. . . the lifter shall bend the knees and lower the body until the surface of
the legs at the hip joint is lower than the tops of
the knees.” The extensors of the ankle, knee, hip,
and trunk first engage in a lengthening (eccentric
contraction) when lowering the body and then a
shortening (concentric contraction) in the upward movement in opposing the force that is applied to
the body from the weights positioned across the shoulders at the back of the neck. Force is similarly
applied to the body at the shoulder region in the
dead lift. However, it is transmitted via tensile force
applied by the weights to the upper extremity and
opposed by concentric contraction of the extensors.
In this lift, a weighted bar is raised from the floor
SQUAT LIFT DEAD LIFT BENCH PRESS
Fig 1. Three competitive powerlifts.
TABLE 1. Perfor mance Results: 1981 Michi gan Teen age Powerlifting C hampion ship
Lift Type Weight Class (lb)
275’/4 242#{189} 220#{188} 198/4 181/4 165’/4 148/4 132/4 123#{189} 114#{189} 105
Squat lift (ib) Mean No.ofsubjects Maximum 305.0 (2) 330 478.3 (3) 550 440.0 (5) 475 375.7 (7) 475 344.4 386.7 (9) (9) 420 450 316.8 (11) 400 292.9 (7) 345 266.3 (4) 330 204.0 (5) 230 146.3 (4) 180
Dead lift (lb) Mean No.ofsubjects Maximum 325.0 (2) 350 526.7 (3) 600 545.0 (6) 600 447.5 (6) 510 425.8 448.8 (12) (8) 550 560 386.5 (10) 465 367.9 (7) 420 357.5 (4) 450 264.0 (5) 280 215.0 (4) 245
Bench press (lb)
Mean No.ofsubjects Maximum 267.5 (2) 310 358.3 (3) 450 298.0 (5) 360 270.0 (6) 340 238.3 259.4 (12) (9) 325 300 200.0 (12) 260 200.0 (7) 245 155.0 (4) 180 142.0 (5) 170 109.0 (4) 140
one continuous motion until the lifter is standing erect”.’
The bench press poses an entirely different prob-lem to the lifter. In this lift, the musculoskeletal
system of the shoulder girdle acts to provide a base of support for the motion of lowering and raising
the weight to and from the chest. Alternately ec-centric and concentric contractions occur in the elbow extensors and horizontal flexors of the
shoul-den joint.
At present, little research has been conducted on adolescent powerlifters. Most research into the
po-tential adverse effects of weight lifting has focused
on adult Olympic-style lifters. Kulund et a!2 studied
80 Olympic-style lifters who performed the squat and dead lift as well as Olympic and other types of
lifts in their weight training program. These lifters reported 1 1 1 injuries. The incidence of injury by
type of lift, areas of the body injured, and duration of impairment, were also reported. The two
pow-erlifts accounted for 32 of the 111 injuries. The
injury potential of these two powerlifts, relative to
the other lifts, can not be determined because train-ing details were not documented. Kotani et a!3 studied 26 outstanding weight lifters who ranged in
age from 18 to 24 years. It was found that 24 of the
26 lifters had recurrent episodes of low back pain. Roentgenogram examinatioon revealed eight cases of spondylolysis, four cases of lumbar spine deform-ity, and two cases of spina bifida occulta.
An increase in strength is a common goal sought by adolescent weight lifters. However, adverse stress on the musculoskeletal system from lifting heavy weights may result in unwarranted risk. This is an important issue, especially in young lifters.
According to a recent policy statement of the Amen-ican Academy of Pediatrics, “. . . weight lifting is a
competitive sport with a high injury rate that
should not be practiced by the preadolescent. Teen-agens who wish to participate should have proper safety precautions and capable supervision.”4
to be relatively unskilled and are apt to try heavy weights in the absence oftrained instructors.” Also,
adolescents are not structurally mature. In fact, the vertebrae of the spine, which are areas of concern, are not completely ossified until 25 to 30 years of
age.6 Mason7 and Troup5 expressed their theoretical concerns for possible deleterious effects of the dead lift on the spines of young lifters. Troup suggested
a marked shearing stress, at the start of the dead
lift, resisted by the pars interarticulanis of succes-sive vertebrae in the region of the vertebral arch between the superior and inferior facets. Jesse8
expressed opposition to any young athlete taking up weight training with weights greater than 40% of body weight prior to one year of basic strength development of spinal muscles through a full range of movement. He suggested a lack of muscular
development of back muscles, improper warm-up, and a lack of lifting skill as contributors to low
back pain and injury.
It is evident that more needs to be known about
the potential adverse effects of weight lifting on adolescent lifters. This is especially true of power-lifting because the body is exposed to resistances of relatively large magnitudes. Thus, the purpose of this study was to construct a profile of the medical
history of adolescent powenlifters in order to
com-prehend more fully the potential for injury in this
sport.
METHODS
The subjects who participated in this study were the 71 male contestants who entered the 1981 Mich-igan Teenage Powerlifting Championship. In-formed consent was obtained from the subjects. A questionnaire, which had been previously pilot tested on college age powenlifters and used in a study of contestants in the 1980 Michigan Teenage Powenlifting Championship,9 was modified to in-dude additional questions on injury types and sites. Questionnaire items required short fill-in answers and opinion scale responses. These questions were designed to elicit information about the training,
experience, and medical history ofthe lifters so that a profile could be composed. A room, monitored by a proctor familiar with the questionnaire, was set
aside for its administration. Subjects completed the questionnaire when time breaks occurred in their lifting schedule. (A copy of the questionnaire can
be obtained by writing the authors.)
RESULTS
All subjects did not respond to all questionnaire
items and some responses were not interpretable. Therefore, the number of subjects responding to
each questionnaire item varied. Subject response
numbers are indicated throughout this report.
Training and Experience
Data on the training and experience of the lifters
were compiled by age in years (Table 2). From Table
2 and other computed values, several facts were
evident. The average powerlifting experience of all subjects was 17.1 months. However, a median value
of 11.9 months indicated that more than 50% of the respondents were involved with powenlifting for less than 1 year; the minimum experience was 2
months and the maximum was 46 months. The average subject began participation in powerlifting
at 15.3 years of age and had previously participated
in 3.4 contests. However, 70.0% of the subjects had
participated in three contests or less. For 21.7% of the subjects, the present contest was their first.
Throughout their entire powerlifting experience,
the average subject trained 4.1 times per week and spent 99.2 minutes per training session. On the average, training was performed alone or with friends, without the supervision of a “trained coach,” 51.6% of the time. There was a tendency toward an increased percentage of training alone or with friends, without the supervision of a “trained
coach,” with increase in age. In fact, 99.0% of the
19-year-old subjects trained in this manner. The training sites varied. The greatest percent of train-ing time (37.7%) occurred at school. This average
figure may have been even higher if the 19-year-old subjects, who were probably no longer in school,
were excluded from the calculation.
An evaluation of where the lifters obtained their
knowledge of powerlifting resulted in two interest-ing relationships. First, there was a tendency to-ward a direct relationship between percent of
knowledge obtained by trial and error and increased
age. Second, the percent of knowledge obtained
from “trained coaches and instructors” tended to
be inversely related to age. On the average, 48.6%
of the lifters’ knowledge of powerlifting was ob-tamed from “trained coaches and instructors.” The average subject obtained 26.1% of his knowledge
from trial and error. Knowledge obtained in this
manner may be somewhat dangerous, especially
when lifting heavy weights.
Approximately 44% of the subjects engaged in intentional weight loss to compete in a lower weight class in the Michigan Teenage Powerlifting
Cham-pionship. Lifters who purposefully lost weight, lost
Selected Questionnaire Items Age (yr)
14 15 16 17 18
Entire Population
19 Not
Given
Av powerlifting experience (mo)
Av no. of powerlifting contests
previ-ously entered
Av no. of workouts per week
Av time/workout (mm)
Av %of time training
Alone
With friends, without supervision of trained coach
Under supervision of trained coach
Av % of time training At home or friend’s home
At gym/YMCA
At school
Other
Av % of knowledge about powerlifting obtained from:
Trial and error
Friends
Trained coaches and instructors
Reading and films
Other 17.1 (59) 3.4 (60) 4.1 (62) 99.2 (59) 23.2 (61) 28.4 (61) 48.4 (61) 28.9 (61) 28.8 (61) 37.7 (61) 4.6 (61) 26.1 (58) 15.3 (58) 48.6 (58) 9.9 (58) 0.2 (58) 73.9 (34) 8.0 (34) 15.2 (34) 0.0 (34) 2.9 (34) 44.3 (61)
the beneficial or harmful effects of intentional gions of the body. This information was evaluated
weight loss in this population must be withheld. over three time intervals (when lifting, immediately
after workouts, and between workouts). The
de-scriptive scale for the occurrence of pain ranged from never to always. The descriptive scale for the Information about the occurrence and level of level of pain ranged from none to severe. The pain associated with teenage participation in pow- percent of subjects who indicated various scale
erlifting was obtained from the subjects on 13 re- levels is summarized in Fig 2 for the upper
extrem-TABLE 2. Subject Training and Experience*
Av % of treatment of injuries that
caused training discontinuance
11.0 10.9 13.1 11.6 16.0 19.4 15.3
(2) (11) (15) (10) (14) (4) (3)
2.5 3.0 2.1 2.3 5.2 6.4 3.2
(2) (11) (14) (10) (14) (5) (5)
3.5 4.2 4.1 3.8 4.2 3.8 4.3
(2) (11) (14) (10) (14) (5) (6)
105.0 95.5 85.4 107.0 108.9 120.0 73.8
(2) (10) (14) (10) (14) (5) (4)
25.0 10.4 9.0 17.8 42.4 69.0 4.3
(2) (11) (14) (9) (14) (5) (6)
10.0 33.8 33.0 19.4 28.4 30.0 25.8
(2) (11) (14) (9) (14) (5) (6)
65.0 55.8 58.0 62.8 29.2 1.0 69.8
(2) (11) (14) (9) (14) (5) (6)
10.0 27.8 9.6 39.6 43.5 32.0 29.3
(2) (11) (14) (9) (14) (5) (6)
90.0 20.0 37.1 12.2 25.9 62.0 9.2
(2) (11) (14) (9) (14) (5) (6)
0.0 45.4 51.8 39.9 23.4 6.0 59.8
(2) (11) (14) (9) (14) (5) (6)
0.0 6.8 1.4 8.3 7.1 0.0 1.7
(2) (11) (14) (9) (14) (5) (6)
7.5 10.4 23.3 21.9 37.5 70.0 6.0
(2) (11) (12) (9) (14) (5) (5)
0.0 29.8 10.0 12.0 12.9 10.0 20.0
(2) (11) (12) (9) (14) (5) (5)
92.5 57.5 61.3 53.9 27.8 8.4 70.0
(2) (11) (12) (9) (14) (5) (5)
0.0 2.3 5.4 11.1 21.9 11.6 4.0
(2) (11) (12) (9) (14) (5) (5)
0.0 0.0 0.0 1.1 0.0 0.0 0.0
(2) (11) (12) (9) (14) (5) (5)
Rest 100.0 66.7 73.8 74.8 65.6 99.8 25.0
(2) (3) (8) (6) (8) (5) (2)
Trainer 0.0 0.0 20.0 0.2 13.8 0.0 0.0
(2) (3) (8) (6) (8) (5) (2)
Medical doctor, without surgery 0.0 0.0 6.3 25.0 20.6 0.2 75.0
(2) (3) (8) (6) (8) (5) (2)
Surgery 0.0 0.0 0.0 0.0 0.0 0.0 0.0
(2) (3) (8) (6) (8) (5) (2)
Other 0.0 33.3 0.0 0.0 0.0 0.0 0.0
(2) (3) (8) (6) (8) (5) (2)
% of contestants who lost weight to en- 50.0 45.4 33.3 40.0 46.2 60.0 60.0
ter lower weight class (2) (11) (15) (10) (13) (5) (5)
* Number of subjects by grouping who responded to questionnaire items is shown in parentheses.
Most of the time
22! to always
Extremity
I00
75
Shoulders % 50
25 22.0 90
0.2 iO.3 iO.3 2 i
0
____________
l00
75
Elbows % 5
(58)
25
6.9 52 52 8.6 i0. i2.i
0 _____________
100
75
Wrists O/ so (57)
2: Lis
I00
75 Hands O/ 50
(57)
25
7.0 7.0 5.3 8.8 70 7.0
0 F k’W _________________
None
67 2
40.7
8.6 69 69 120 2.0
__________________
2i I 22.8 21 I fI810.5
21.0 r1123 I23
I
Time Interval !‘
0
>. 8
S 8 8 8
i!
OccurrencePAIN
Level
Almost never Sometimes
to never
Somewhat severe
Moderate to mild to severe
*Numbers in parentheses are the minimum number of subjects who responded by body region
Fig 2. Upper extremity, occurrence and level of pain. Minimum number of subjects who responded by body region is shown in parentheses.
ity, Fig 3 for the lower extremity, and Fig 4 for the
axial body.
In the upper extremity (Fig 2), the greatest
per-centage of subjects indicated higher incidences and
levels of pain in the shoulder over the three time intervals. When lifting, 32.2% of the subjects
mdi-cated an occurrence of pain sometimes to always and 50.9% indicated a mild to severe level of pain in the shoulder region. Pain occurred in the wrists sometimes to most of the time in 26.3% of the respondents when they were lifting and the level of
pain in the wrists when lifting was mild to severe
in 31.6% of the subjects. The percent of subjects indicating an occurrence of pain in the wrists most
of the time to always (10.5%) and a level of wrist
pain somewhat severe to severe (10.5%) when
lift-ing was considerably reduced after and between
workouts.
In the lower extremity (Fig 3), the greatest
per-centage of subjects indicated higher incidences and
levels of pain in the knee over the three time intervals. An occurrence of pain sometimes to
al-ways in the knee was indicated by 21.6% to 31.6%
of the subjects over the three time intervals. A mild to severe level of pain in the knees over the three
time intervals was indicated by 33.3% to 42.2% of
the subjects. The hip was another region of the lower extremity in which the occurrence of pain was increased. Pain occurred in the hips sometimes
Mostofthetime Almostnever
Sometimes
Lower to always to never
Extremity
100 r
j:
_
Hips % 50
(55)*
25L
16.1L
.36 3617__________
91 11.9100
75
F’
Groin %s4.
25
(58)
II .9
0L
o 0 0___________
100
7511
Knees %
54-25L 15.8 58 17.0 57
(5’)
L
r-00
75
r
Ankles % 501
(57)
25
L
L
1.7 .8 .8 4ii.8 .826.8 25.4 5.4 36
r-k4_0 _______________
20.4
j4l.7
r-0 8.8 7
r
33.4 32 I 33.3 2.36670.3 88 88 0 0 0
Time Interval ‘
000
.5
t 2
-.
- . 0 C
-:
0 0 0 000
S a C
- V
PAIN
Occurrence Level
100
75 Feet % 50
(55)
25
0
-
________
inparentheses ore the minimum number of subjects who responded bybody region.
Somewhat severe
Moderate to mild None
to severe
Fig 3. Lower extremity, occurrence and level of pain. Minimum number of subjects who responded by body region is shown in parentheses.
32.2% of the subjects.
An evaluation of all regions of the body showed
that the axial regions of the upper and lower back
had the highest percent of subjects who indicated
an increased occurrence and level of pain (Fig 4). In the upper back, 20.7% to 31.0% of the respond-ents indicated that they sometimes had pain over the three time intervals. Few subjects responded to
a higher incidence ofpain in this region. The upper
back pain level was mild to moderate in 37.9% to 50.0% of the subjects. Only a few subjects indicated
a level of pain in the upper back more severe than
moderate. Ofall the regions ofthe body, the greatest percentage of subjects indicated higher occurrences
and levels of pain in the low back over the three time intervals. In fact, 60.0% to 66.7% of these
lifters recorded an occurrence of pain sometimes to
Occurrence
Almost never Sometimes
to never
qI Body Regions
100
r
75F
Neck %
50-(59)*
25L
iso 5.2 360 _____________
Level
Somewhat severe Moderate to mild None to severe
35.0 339
_Li_ 0 ______________
Abdomen
(stomach
region)
(58)
100
75
% 50 25 0
34 3.4 3.4
----‘--LJ.6.9 69
I
Time Interval . .
I!!
3.4 3.4 3.4
22.4
..
2
#{149}!
..
i 8S
a’ 8
V
E
PAIN
Upper Back
(53)
Most of the time
to always
I 00 75
[
%
_
20725
__________
__________
0 578.6 0 _L!._L7
60.3
50.0 50.0
r-i1#{149}r-1
Lower Bock
(52)
100
75
25
___
___
___
L
iii
21222.8182 952749iri\
0/0 50 28 8 40.4 40.0 40.0 26.9 246 32.7
*Nums in parentheses are the minimum number of subjects who responded by body region.
Fig 4. Axial body regions, occurrence and level of pain. Minimum number of subjects who responded by body region is shown in parentheses.
40.0% recorded an incidence of almost never to never. The level of pain in the low back region was
correspondingly high. Somewhat severe to severe
pain was indicated by 18.2% to 22.8% of these teenage powerlifters over the three time intervals.
Mild to moderate levels of pain were reported in
49.1% to 52.7% of the subjects.
In addition to the occurrence and level of pain,
subjects responded to questionnaire items on types and sites of injuries that were severe enough to cause them to discontinue training for at least one day. The results of this phase of the questionnaire are shown in Fig 5. Of 71 subjects responding to
injury types and sites, 28 subjects recorded at least
one injury that caused them to discontinue their
training. In all, 98 injuries by type and site were
recorded. These injuries caused a discontinuance of training for a total of 1,126 days or an average of
11.5 successive days discontinued per injury.
A summary of injury types reported by the lifters
is presented in Fig 5 for general information.
Valid-ity of subject responses regarding injury type may be questionable because of their lack of diagnostic training. Because only 23.2% of all recorded injuries that caused a discontinuance of training were treated by someone trained in diagnosing injury types (Table 1), this information would be difficult to obtain. It is evident that the injury type with the highest incidence (61.2%), as indicated by the
sub-jects, was muscle pull. Muscle-associated injuries
9
‘4
0
‘4 4,
4,
0 4’
0
4,
(J_) cl
w .
‘:: (I)
>-c
-, E E
!
‘;c -;
4, 4, .a
rniii-..
I:!
gi
0 !‘!1
I-4i0
_2 w :x:
a discontinuance of training.
Injury site evaluation was divided into the regions of the upper extremity, lower extremity, and axial body (Fig 5). In the upper extremity, the elbow and
shoulder were sites of the highest incidence of
in-jury, each accounting for 6.1% of all injuries. In the
lower extremity, the knee was the site of greatest
injury (8.2%). The axial body site of the low back
accounted for 50% of all incidents of injury sites. The low back was by far the site with the highest
incidence of injury.
The percent of total days missed by injury type
and site was calculated and included in parentheses in Fig 5. These values, in comparison with the respective type and site response percents, provide
a scale of immediate injury severity. For example,
6.1% of all incidences of injuries reported were in
the elbow. These elbow injuries caused a discontin-uance of training equal to 12.9% of the total days
discontinued due to all injuries. Therefore, elbow injuries caused a disproportionately longer discon-tinuance of training than the average injury. On the other hand, low back injuries caused a dispro-portionately short stoppage of training. A similar comparison by injury type can be made by using the pairs of calculated percentage values in Fig 5. Muscle pulls, cramps, abrasions, and sprains, on the average, tended to be less debilitating than
tendonitis, nerve injuries, broken bones, and dislo-cations.
What relationships existed between the site of pain (Figs 2 to 4) and the sites of injuries (Fig 5)? First, it should be noted that chest and thigh were not included as response areas under questionnaire items related to the occurrence and level of pain. Therefore, no relationships could be drawn about these areas. However, other sites with high injury response percents (knee, shoulder, elbow, and low
back) were also regions of the body in which a
higher percent of subjects indicated elevated occur-rences and levels of pain. This relationship is most evident in the low back region where: (1) the
great-est percent of subjects indicated higher occurrences
and levels of pain; (2) 50% of all powerlifting inju-ries were reported to have occurred; and (3) 41.3% of the total days of training missed due to injury occurred.
DISCUSSION
AND SUMMARY
This study was conducted to construct a profile
of the medical history of adolescent powerlifters in
order to comprehend more fully the risks associated with participation in.this sport. The subjects se-lected for study were contestants in the 1981
Mich-igan Teenage Powerlifting Championship. An
eva!-uation of their training revealed them to be rela-tively inexperienced, as would be expected because of their age. Fewer than 50% of the subjects had
participated in powerlifting for 1 year or more. However, they trained an average of 6.8 h/wk.
Analysis of the occurrence and level of pain in 13
regions of the body implicated powenlifting as po-tentially injurious to the low back, knee, shoulder, and elbow. This was substantiated by an evaluation
of the 98 powerlifting injuries reported by the
sub-jects. The low back region was the dominant injury
site; 50% of all injuries occurred in this region. The
knee, shoulder, and elbow were other sites of ele-vated injury occurrences. Musculoskeletal injuries (muscle pulls, tendonitis, cramps, sprains, broken
bones, and dislocations) were perceived to account
for 90.7% of all injury types.
The findings are specific to the teenage
popula-tion studied. However, the results can provide input into an assessment of the immediate risks of pow-erlifting relative to the purported benefits of this sport. Because this study was cross sectional,
prog-nosis about the long-term effects of powerlifting is
not warranted, but is in need of further study. The findings of this study are not only important to those associated with teenage powerlifting, but also to the many young athletes who perform powerlifts
as part of their weight training program for other
sports.
REFERENCES
1. Patterson C: Official Rules ofthe International Powerlifting Association. Cedar Hill, TX, AAU-TPBA, 1978, pp, 19, 21 2. Kuland DN, Dewey JB, Brubaker CE, et al: Olympic
weight-lifting injuries. Physician Sports Med 1978;6:111
3. Kotani PT, Ichikawa N, Wakabayashi W, et al: Studies of
spondylolysis found among weight lifters. Br J Sports Med 1971;6:4
4. American Academy of Pediatrics: Committee on Sports Medicine: Weight Training and Weight Lifting Information for the Pediatrician. News and Comment 1982;35:7 5. Troup JDG: The risk of weight-training and weight lifting
in young people: functional anatomy of the spine. Br J Sports Med 1970;5:27
6. Gray H: Gray’s Anatomy: The Classic Collector’s Edition.
New York, Bounty Books, 1977
7. Mason TA: Is weight lifting deleterious to the spines of young people? Br J Sports Med 1970;5:54
8. Jesse JP: Olympic Lifting Movements Endanger Adoles-cents. Physician Sports Med 1977:5:61