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.