Stress fractures—a prospective study amongst recruits
BACKGROUND Stress fracture (SF) is the single most common cause for the lost number of manpower days during training of recruits in the Armed Forces. This prospective study was undertaken with a view to develop baseline data on incidence of SF and to identify related variables. METHOD A prospective study over a period of five years during 2004–2009 in which a total of 8,570 recruits were enrolled at the start of their training to find out the incidence and pattern of SFs. RESULTS A total of 604 (7.04%, 95% CI 6.40–7.40%) out of a total of 8,570 recruits sustained SF during the study period. The majority of fractures occurred during basic training. The factors like urban residence, vegetarianism and those without prior history of physical activity were found to be associated with SF. Tibia was the commonest bone involved. CONCLUSION Prevention is undoubtedly the best approach in SF and other sports injuries. Priority should be given to individuals with good sports and physical activity background during recruitment. Intensity of training should be gradually increased during first three months (12 weeks) of training.
MJAFI Vol 68 No 2 118 © 2012, AFMS
*Ex-Senior Advisor (Surgery), Command Hospital (SC), Pune – 40,
Professor, Department of Community Medicine, AFMC, Pune – 40.
Correspondence: Lt Col AS Kushwaha, Associate Professor,
Department of Community Medicine, AFMC, Pune – 40.
Received: 14.06.2011; Accepted: 05.12.2011
isolated studies done on the subject though some intervention
studies on its management are reported.
There is a paucity
of prospective studies on the incidence of SF in the Indian
This prospective study was embarked on with a view
to develop baseline data on incidence of SF and to identify re-
lated variables. Stress fracture is the single most common
cause for the lost number of manpower days during training of
recruits in the Armed Forces. Stress fractures are among the
five most common running injuries, and account for 50% of all
injuries sustained by runners and military recruits.
dence of SF ranges from 1.5% to 31%.
Women are reported to
be at greater risk, with one study reporting a two-fold increase
of bilateral SF over men.
Stress fractures were first described
in the medical literature as March Fractures by Briethaupt in
1855 who found them in the metatarsals of the Prussian Army
There are no data available on SF amongst Indian
women but there is a need for research in this direction as well
due to induction of women in the defence forces. There are
very few prospective studies on SF available in the literature.
Strategies designed to prevent SF are not well understood.
Proposed strategies include gradual and progressive initiation
of vigorous physical training,
recovery periods with no
running or marching after 2–3 weeks of training,
proper running shoes,
use of shock-absorbent insoles, use of
orthotic shoe inserts, and adherence to an appropriate diet.
While a number of prevention strategies have been recom-
mended, few have been evaluated adequately.
MATERIALS AND METHOD
A prospective study was carried out to find the incidence of SF
amongst recruits undergoing training at a regimental training
centre located in southern India with recruits drawn from
southern states. The centre has one MO posted with it. The
centre is located at an altitude of 6,000 ft in the Nilgiri Hills of
Tamil Nadu. Annually 800–1,200 recruits join at the training
centre depending on the requirement. Over a period of five
years between 2004 and 2009, a total of 8,570 recruits were
enrolled into the study at the start of their training to find out
the incidence and pattern of SF. Details were recorded on their
demographic parameters, dietary history and relevant history
on prior physical activity. Prior physical activity was consid-
ered to be present prior to training if the recruit had a history
of participation in sports and games activity at inter school,
zonal, state or national level in track and field events, and field
sports like football, hockey, volleyball, basketball, handball,
Stress fractures—a prospective study amongst recruits
Col Niranjan Dash (Retd)*, Lt Col AS Kushwaha
Stress fracture (SF) is the single most common cause for the lost number
of manpower days during training of recruits in the Armed Forces. This
prospective study was undertaken with a view to develop baseline data
on incidence of SF and to identify related variables.
A prospective study over a period of five years during 2004–2009 in
which a total of 8,570 recruits were enrolled at the start of their training
to find out the incidence and pattern of SFs.
A total of 604 (7.04%, 95% CI 6.40–7.40%) out of a total of 8,570
recruits sustained SF during the study period. The majority of fractures
occurred during basic training. The factors like urban residence, vegetari-
anism and those without prior history of physical activity were found to
be associated with SF. Tibia was the commonest bone involved.
Prevention is undoubtedly the best approach in SF and other sports inju-
ries. Priority should be given to individuals with good sports and physical
activity background during recruitment. Intensity of training should be
gradually increased during first three months (12 weeks) of training.
Key Words: recruits; stress fracture
The problem of stress fractures (SF) amongst athletes and re-
cruits is as old as the history of military itself. Though, it has been
known since antiquity, exact understanding of its mechanism,
prediction, and prevention has been not researched enough
and no army can claim to have eliminated this disorder.
The literature on its prevalence from India is scanty with few
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Stress Fractures—A Prospective Study Amongst Recruits
wrestling, boxing, etc. Dietary habits (vegetarian and non-
vegetarian) were also noted. The recruits thus enrolled were
followed up through their training period for occurrence of SF.
Details of their training schedule were obtained. On occur-
rence of SF, the history of clinical features, bone involved, and
site affected were noted. In case of tibial fractures intercondy-
lar and inter malleolar distance was measured to find any rela-
tive bowleg and knock knee. The SF were graded in to four
groups based on the suggested clinic-radiological classification
by Agarwal et al,
and further modified by us as given in Table 1.
The 604 cases were managed with standard measures which in-
cluded rest, immobilisation, and dietary supplementation and
observed in low medical category and sick leave depending
upon the classification of the SF.
A total of 604 (7.04%, 95% CI 6.40–7.40%) out of a total
of 8,570 recruits enrolled for undergoing training between
2004 and 2009 sustained SF during this study period. On study
of distribution of SF cases according to clinicoradiological
classification in grades, it was observed that two-third cases
of SF belong to grade II (67.5%) and minimum (2.5%) to
grade III (Table 1). It is observed that a major proportion of SF
were concentrated in the training period of basic training phase
from nine weeks to 27 weeks (Table 2). Most of the SF in this
prospective study involved tibia whereas, the metatarsals were
least affected. As the tibia was the most common bone in-
volved (n = 535, 88.57%) we studied the distribution of SF ac-
cording to the region involved and it was seen that upper
one-third of tibia was the predominant site affected (Table 3).
The occurrence of SF in recruits from urban area is signifi-
cantly more (P = 0.000) in comparison to those from rural area.
It is observed that the occurrence of SF is significantly more
(P = 0.000) in recruits who were not involved in prior physical
activity in comparison to recruits having prior physical activ-
ity. It is also observed that the incidence of SF is significantly
more in recruits with vegetarian dietary habit in comparison to
non-vegetarians (P = 0.000) (Table 4).
Disposal and Outcome of All Stress Fracture Cases After
It is observed that two-third of the cases of SF required sick
leave after a brief hospitalisation. About a quarter of all cases
showed good recovery only after brief hospitalisation. Average
duration of hospitalisation for grade I SF was 16.3 days (varied
from one week to four weeks). They were discharged from
Table 1 Distribution of stress fracture according to clinicoradiological classification.
Grades Clinical picture (at presentation) Radiography (at two week; plain radiograph) SF n (%)
I Mild pain Periosteal reaction 163 (27)
Walks without pain
II Severe pain Hair line crack of cortex 410 (67.5)
Walks without support
III Severe pain Partial thickness involvement of cortex 13 (2.5)
Walks with support
IV Severe pain
Cannot walk/walks with difficulty even with support Full thickness of cortex involved 18 (3)
Total 604 (100)
SF: stress fractures.
Table 2 Distribution of onset of stress fractures according to duration of training.
Onset of training (wk) Phase* 1999–2000 2000–2001 2001–2002 2002–2003 2003–2004 Total n (%)
Up to 8 ‘O’ training phase 3 0 0 2 0 5 (0.82)
9–27 Basic training 98 58 59 88 176 479 (79.3)
28–31 Four week leave
32–46 Advanced training 23 31 22 18 26 120 (19.86)
Total 124 89 81 108 202 604 (100)
*‘O’ phase training: education, WT, PT—1 mile, drill; basic training: battle physical efficiency test, drill without arms, battle obstacle course, firing, route march—12 Km;
advanced training: battle physical efficiency test, route march of 20 Km, 30 Km, and 40 Km.
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recruits by Scully and Besterman,
to high as 31% reported by
Giladi et al among 295 recruits of the Israeli Army.
series of 1,014 recruits published by Singh et al, the incidence
In another Indian series
the total number of re-
cruits who underwent training over five years was 12,700 out
of whom 1,452 were diagnosed as cases of SF (11.4%). The SF
incidence of 7.04% in our study is not on the higher side in
comparison to the Indian series.
There is no classification described for SF in the literature
based on clinical features and plain radiographic findings.
Hence, this modified classification by Agarwal et al was used
in categorising SF, planning management, and also prognosti-
In a large Indian series based on similar classification
by Agarwal et al it was found that the most common grade
of SF was grade I.
However, in our series, the common grade
of SF was grade II followed by grade I. Greaney et al
Gracic et al
reported that 60% and 40% of SF, respectively,
had occurred during the initial military training. According
to Giladi et al the occurrence of SF was found maximum at
14 weeks of training.
Sterling et al observed the maximum
occurrence of SF at 15 weeks of training.
In this study, the
maximum occurrence of SF is found between nine weeks and
27 weeks, i.e. the basic phase of training similar to the study
by Giladi et al.
The distribution of sites of SF in this study is
similar to the other military studies.
The most affected
bone is tibia and the common site of tibial involvement is the
upper one-third which is similar to Orava et al and Singh et al.
The lower one-third SF of tibia is common amongst recruits
having mild knock knee. In our series, it was decided to study
whether the intercondylar distance (relative bow leg) made
any significant difference to the site of SF. It is observed that
greater the intercondylar distance more were chances of in-
volvement of upper one-third of tibia, though not statistically
significant. Similarly, the study was undertaken to correlate the
significance of inter malleolar distance (relative knock knee)
with the occurrence of SF at the lower one-third of tibia, again
not statistically significant. Though, it is mentioned in the text-
books that bowleg and knock knee do increase the incidence
of SF of tibia, no intercondylar or inter malleolar distance
study has been carried out earlier in the literature.
There is marked and significant difference in the incidence
of SF in recruits from urban areas (10.08%) in comparison to
hospital without sick leave. Grade II SF were kept in hospital
for a minimum of four weeks and sent on sick leave for 4–8
weeks depending on response to treatment. Grade III SF after
four weeks of hospitalisation and sick leave of 4–12 weeks were
observed in low med cat (LMC) at the regimental centre for a
maximum period of 12 weeks with some light duties and sub-
sequently upgraded to A1 (fit for continuing training activities).
A total of 21 cases (3.46%) of SF had to be invalided out of
service due to poor response to management and their inability
to continue training. One case of grade II SF was observed in
LMC for 12 weeks but despite this he had to be invalided out
because of inadequate response to management. Two cases of
grade III SF had to be invalided out. All 18 recruits of category IV
SF could not continue their training because of persistent pain
at the site of fracture in spite of satisfactory radiological oste-
oblastic activity (bone union). Hence, they were boarded out
Stress fracture is the single largest cause of loss of training
among military recruits.
However, the incidence of SF among
military recruits vary widely from 1.3% reported among 6,677
Table 4 Distribution of stress fractures cases according to place of residence prior to training, history of prior physical activity, and dietary habits.
Parameter Class SF occurred (%) SF not occurred (%) c
test P value*
Place of residence Urban (3,558) 362 (10.1) 3,196 (89.9) 90.77 0
Rural (5,012) 242 (4.8) 4,770 (95.2)
Prior physical activity Present (1,960) 99 (5.0) 1,861 (95.0) 15.47 0
Absent (6,610) 505 (7.6) 6,105 (92.4)
Dietary habit Veg (2,131) 209 (9.8) 1,922 (90.2) 32.97 0
Non-veg (6,439) 395 (6.1) 6,044 (93.9)
*P value significant at < 0.05.
SF: stress fractures.
Table 3 Distribution of stress fractures according to bones affected.
Bones No. of cases (%) Distribution of tibial involvement
Femur 10 (1.65)
Tibia 535 (88.57) Site of tibia involved No. of SF (%)
Upper 1/3rd 382 (71.4)
Middle 1/3rd 89 (16.63)
Lower 1/3rd 64 (11.96)
Total 535 (100)
Fibula 56 (9.27) 50 cases of lower 1/3 fibula,
six middle 1/3 fibula
Metatarsals 3 (0.5) Two involved 3rd metatarsal,
one case 4th metatarsal
Total 604 (100)
SF: stress fractures.
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Stress Fractures—A Prospective Study Amongst Recruits
Intellectual Contributions of Authors
Study concept: Col Niranjan Das (Retd)
Drafting and manuscript revision: Col Niranjan Das (Retd),
Lt Col AS Kushwaha
Technical support: Lt Col AS Kushwaha
Study supervision: Col Niranjan Das (Retd), Lt Col AS
CONFLICTS OF INTEREST
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In our study it is interesting to observe that the incidence of
SF increases (5.89%) in recruits with history of no physical
activity in comparison to recruits with history of physical activity
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(9.8%) in a vegetarian recruit in comparison to non-vegetarians
(6.13%). Though, it is mentioned in the textbooks that dietary/
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(NSAIDs) and cyclooxygenase two selective NSAIDs.
we treated cases of SF with severe unbearable pain with non-
specific NSAIDs and got satisfactory clinical response.
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cases were SF femur out of a total of 10 cases (60%), 11 cases
were SF tibia, and four cases were SF both tibia and fibula. Out
of 15 cases of SF tibia (invalided out), eight were upper one-
third and four were lower one-third and were associated with
relative bow leg and relative knock knees, respectively, and
the remaining three cases were SF of middle one-third of tibia.
Out of 21 cases of SF invalided out, 16 were having an urban
back ground with history of less physical activities in compari-
son to five cases of SF of rural background with history of
more physical activities.
Our study brings out the fact that those with prior physical
activity, non-vegetarian diet, and belonging to rural area had
significantly lower incidence of SF. Priority should be given to
individuals with good sports and physical activity background
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Dash and Kushwaha
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factors, except for gender, were also related to overuse injuries.
The authors concluded that during BCT, adiposity expressed
as BFP and not as BMI can predict the magnitude and type
(acute-overuse) of musculoskeletal injuries in Greek cadets.
Col MM Harjai*
*Senior Advisor (Surgery and Paediatric Surgery),
Command Hospital (SC), Pune – 40.
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