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Recreational Injury Interventions
Running
Background
Running is one of the most common activities
during which overuse injuries of the lower extremities occur. These injuries occur
when the lower extremities are exposed to a large number of repetitive forces, which
individually will not cause an acute injury, but cumulatively overtime can cause
fatigue and overuse injuries such as stress fracture, shin splints, chondromalacia
patellae, plantar fasciitis, and Achilles tendinitis. Amongst recreational and competitive
runners, between 27% and 70% sustain overuse injuries during any 1-year period,
Hreljac et al, 2000.
The benefits of running are not limited to an increase of cardiovasuclar
strength. The initial stress of an intensive physical conditioning program promotes
bone remodeling and the formation of new more structurally stable bone. There is,
however, a lag between new bone formation and a state in which the bone is temporarily
more weakened and susceptible to stress fracture. Therefore, a sudden increase in
training intensity could contribute to overuse injury. Proposed training programs
including rest periods, stretching, use of protective devices such as braces and
insoles, and reduced frequency and duration of running impact may be essential in
reducing the risk of running injuries. Agreement has yet to be reached regarding
the the benefits of modified training programs and the amount and timing of rest
periods, Popovich et al, 2000.
Additionally, the anatomical and biomechanical variables of each
individual must be considered to determine their own limits of an injury free training
program. Three studies below attempt to identify the role of
modified training programs and physical variables in the causation of overuse injury
in adolescent and adult runners participating in recreational, competitive, and
military training activities. The relative level of training intensity varies across
groups and should be considered when evaluating injury rates.
Review of running studies:
Author | Yeung & Yeung, 2001 |
Study design and target population | Review of randomized controlled trials. Population:
12 trials with 8,806 runners from adolescence to middle age. |
Intervention | Lower limb soft-tissue running injury preventions including;
stretching, modfied training schedules, and use of protective devices. |
Outcomes | Incidence of lower limb injury,
severity, complication of intervention, compliance with intervention, and
measure of service utilization (medical visits, cost of devices). |
Results | No overall evidence of significant
protection against soft tissue injury from stretching exercises.
Subjects tended to comply more with warm-up and cool-down exercises
than stretching routine, (RR 0.46; 95% CI 0.36 to 0.59; RR 0.54; 95% CI
0.43 to 0.69).
Reducing frequency (RR 0.19; 95% CI 0.06 to 0.66) or duration
(RR 0.41; 95% CI 0.21 to 0.79) of training significantly reduced injury
incidence.
No significant difference in risk reduction for heel pads/inserts
and shock absorbing soles.
Significant reduction, (RR 0.35; 95% CI 0.13 to 0.91) in
incidence of anterior knee pain in 8 week training regime.
No difference in incidence of shin splints with combined
stretching and insole strategy (RR 1.05; 95% CI 0.58 to 1.90). |
Study quality and conclusions | No benefit was found from stretching interventions.
Reduction in duration, frequency, or distance could influence
risk of overuse injuries.
Shock absorbing insoles show no significant benefit. Knee
braces appear to be effective in the prevention of anterior knee pain.
Injury defined differently between
studies. Injury severity not stated in some trials.
Study population subject to a higher
than average training load.
Some control and intervention groups
exposed to stretching prior to training. Population composed mainly of young,
active males, in the military. |
Author | Popovich, et al., 2000 |
Study design and target population | Non-random controlled trial.
Population: 1357 male military recruits, participated
Sept-Nov 1989. Median age 18, range 17-40 years. |
Intervention | 8-week basic military training (BMT) program, including
running and marching with rest intervention during 2nd, 3rd, & 4th weeks. |
Outcomes | Daily training documented in logs.
Performance recorded with Amry physical fitness test (APFT).
All medical clinic visits and injuries and illness were
abstracted from recruit's medical records. |
Results | No reduction in stress fx/rx or
other injuries in the intervention companies compared to their controls.
236 (17%) of recruits with overuse injury. 144 (11%) with traumatic
injury.
Stress fx/rx rate 3-8 per 100 recruits in intervention groups,
and 2-7 per 100 in controls. Total injury rate 18-35 per 100 in intervention
groups, and 18-29 in controls. |
Study quality and conclusions | No evidence of protective effect
on overuse injuries from 1 week of resting period during any stage of training.
Injury rates more likely related to other variables and not intervention.
Consistent training schedules were not maintained. |
Author | Hreljac, et al., 2000 |
Study design and target population | Case control study. Population:
2 groups of 8 female and 12 male competitive runners in Auckland, NZ.
One group injury free (IF), other
with at least one overuse injury, (I). |
Intervention | Questionnaire used to collect training data. Anatomical
data collected, and biomechanical data collected in laboratory. |
Outcomes | Biomechanical data. Variable
stride measures. |
Results | No significant difference between groups in average
running pace, or weekly distance run (I=77.8 +
43.4km, IF=72.5 + 39.6km).
IF group performed signifcantly better in sit and reach
test compared to I group, (IF=3.2 + 10.2cm, I= -3.7 + 11.5cm).
Significant differences between groups for vertical force
impact peak & maximal vertical loading rate. IF group demonstrated significantly
lower values. |
Study quality and conclusions | Stride patterns that incorporate relatively low impact
forces and moderately rapid rate of pronation reduce risk of overuse running
injuries.
Anatomical and biomechanical variables determine limits of an individual's
susceptibility to injury and should be considered when defining an injury
free training program.
Groups well matched for important variables.
Orthopaedic screening was not predictable tool for predicting
running injuries. |
Summary of running interventions
Modified training programs including rest periods, a reduction in
duration, frequency, or distance may reduce the risk of overuse injuries. Such programs
could benefit runners of all levels, if an individual's anatomical and biomechanical
variables are considered. There is still no consensus regarding the amount and timing
of rest periods. Additionally, sudden changes in training habits or running distance
suggest an increase risk of lower limb injury. Stretching programs and use of shock
absorbing insoles did not appear to be effective in reducing overuse running injuries.
However, this study examined a competitive mostly male population participating
at a relative high level of training intensity who were all exposed to pre-training
stretching. Knee braces appear to be effective in the prevention of anterior knee
pain, but this is the result of a single preliminary study.
Recommendations on running
programs
Training program interventions should consider including stretching
exercises, rest periods, and modified schedules, use of protective devices such
as knee braces and insoles, and the physical limitations or variables of each individual.
Special consideration should be given in early and late phases of training when
there appears to be a peak in stress fracture incidence.
Recommendations for future
research
There is a need for randomized controlled trials of
training program interventions that include stretching exercises, rest periods,
and modified schedules, as past studies have not effectively controlled for consistent
training schedules. Further research should be conducted regarding the benefit of
protective devices such as knee braces and insoles. There is conflicting evidence
regarding the benefit of shock absorbing insoles. Therefore, studies examining the
benefit of shock abosrbing insoles that also modify structural abnormalities should
be considered. Further efforts should also be made to define a reliable tool for
predicting running injuries, and to study the incidence of injury in younger populations,
recreatoinal runners, and female runners.
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