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Recreational Injury Interventions
Physical Conditioning & Stretching
Background Stretching
Many athletes stretch their muscles before exercise because of the common belief
that this reduces the risk of injury. However, the data on the effectiveness of
stretching in preventing injury are very limited. Basic science data would argue
against stretching as a mechanism to prevent injury (Shrier 1999). Increases in resting muscle compliance
are associated with a decrease in resistance to injury in resting animal muscle.
We found two RCTs and one before-after study evaluating the effectiveness of stretching
in preventing musculo-skeletal injuries.
Review of stretching studies:
Author | Pope et al, 2000 |
Study design and target population | Australian Army recruits RCT of platoons: 19 platoons
(735 subjects) to intervention and 20 platoons (803 subjects) to control. |
Intervention | Stretch protocol of 20 sec static stretch for each
muscle group. |
Outcomes | Any lower extremity injury that prevented
returning to full activity within 3 days. |
Results | Overall risk of injury was 5.5 injuries per 1000 training
hours.
HR for the intervention group= 1.04 (95% CI 0.82, 1.33).
No significant effect of stretching
on either soft tissue or bony injuries. |
Study quality and conclusions | Well done study. |
Author | Cross et al, 1999 |
Study design and target population | Before/after study.
195college football players.
|
Intervention | Static stretch program for LE. |
Outcomes | Strain acute injury as certified by an athletic trainer,
resulting in 1 day or more absence from practice. |
Results | Pre: 155 injurie, 28% LE
Post: 153 injuries, 13.7% LE. |
Study quality and conclusions | Weak study design.
|
Author | Van Mechelen, 1993 |
Study design and target population | RCT 421 male recreational runners.
|
Intervention | 16 week intervention of warm up and stretching.
|
Outcomes | |
Results | RR= 1.12 |
Study quality and conclusions | Lot of non-compliance in both groups.
|
Summary of stretching interventions
There is evidence that stretching does not prevent musculo-skeletal injury. The
best evidence comes form the RCT by Pope. This had sufficient power to detect any
clinically important protective effect. This RCT is also supported by a prior systematic
review by Shrier (1999) who found no protective
effect of stretching.
Shrier (2000) also points out that there are
no biological reasons to suspect that stretching would be protective.
1. An increase in tissue compliance is associated with a decreased ability to absorb
energy.
2. Injuries usually occur within the normal range of motion.
3. Even mild stretching can cause damage at the cytoskeletal level.
4. Stretching increases tolerance to pain, which might result in further damage
to injured tissues.
Recommendations on stretching
programs
There is no evidence to recommend stretching programs to prevent
athletic injuries.
Background Conditioning
Conventional wisdom and common sense indicate
that athletes in good physical condition are less susceptible to injury. Cardiovascular
fitness, muscle strength and flexibility are important for general health and well
being as well as athletic performance. Studies which have evaluated various types
of conditioning programs are summarized below.
Review of physical conditioning
studies:
Author | Bixler and Jones, 1992 |
Study design and target population | Most closely resembles cohort study design with elements
of case-cross-over design.
Population: Football players from 5 high schools
in the Mid-Penn Football Conference. |
Intervention | 3 minute warm up and stretching routine prior to start
of second half of game. 3 teams assigned to intervention group, two to control
group. |
Outcomes | Sprain and strain injuries occurring in the third quarter
of game. Also recorded the number and severity of injuries. Injury defined as
an event that was recognized by a trainer and that altered athletic performance.
Severity defined as: Class 1 (any recognized injury) or Class 2 (injuries which
caused player to miss one or more days of practice) |
Results | 108 injuries occurred in 55 games. 38% of injuries
were ligament sprains and muscle strains. Number of third quarter sprains and
strains per game significantly lower in intervention group (p<0.05). |
Study quality and conclusions | Authors conclude short half time routine may reduce
sprains.
Program implemented at the school level; for analysis
intervention group teams were treated as controls when stretching routine
not done at a specific game. No information available about players, equipment,
fields, or football program. |
Author | Cahill and Griffith, 1978
Cahill and Griffith, 1984 |
Study design and target population | Before/after study design.
Population: high school varsity football players
in the Midstate Eight conference, Peoria . 12 years; 3,789 players |
Intervention | Preseason conditioning program (PSC), duration 6 weeks.
Program emphasizes total body conditioning, cardiovascular stressing, acclimatization
to heat, flexibility drills, and agility exercises.
NC 1969-72
(no conditioning)
C1 1973-76, PSC with close supervision
C2 1977-1980, PSC not as closely supervised
by sports medicine staff; coaches could modify program. |
Outcomes | Knee injuries, defined as an injury severe enough to
cause an athlete to miss 2 consecutive practices or one practice and a game. |
Results | Injury rate:
NC 68 per 1000
C1 40 per 1000
C2 40 per 1000
Surgical operations:
NC 15.2 per 1000
C1 5.7 per 1000
C2 2.3 per 1000
Non-surgical hospitalization decreased
C1, C2 from NC levels, p<0.05. |
Study quality and conclusions | District wide program appears to reduce knee injuries
(NC vs C1). Program success maintained under less supervised conditions (C2).
No information given on other facets of the
football program, types of shoes worn, playing surfaces or physical condition
of individual players. |
Author | Heiser et al., 1984 |
Study design and target population | Before/after study design.
Population: Intercollegiate football players
at University of Nebraska, 1973-1982 |
Intervention | Cybex II testing to detect muscle imbalances monitor
hamstring strain rehabilitation. Isokinetic rehabilitation program to correct
muscle imbalance initiated prior to season. |
Outcomes | Hamstring muscle strains (both primary and recurrent) |
Results | Group I (pre-Cybex) 41 primary hamstring strains in
534 player-years (7.7%); 13 players had recurrences (31.7%).
Group II (post Cybex) 6 injuries in 564 player-years
(1.1%), no recurrences. |
Study quality and conclusions | Isokinetic testing and rehabilitation of muscle imbalances
can prevent hamstring strains, aid in rehabilitation and prevent recurrences.
Data not presented in article. No information
on injury by player position. Group II: Conditioning program changed with
the addition of closely supervised strength training for all players and increased
emphasis on stretching. |
Summary of physical conditioning
interventions
The Heiser and Cahill
sudies25-27 indicate that specific conditioning programs
may reduce hamstring muscle strain and knee injuries in football. While one would
expect that a well conditioned athlete would be less likely to be injured, there
is no research evidence to support this statement.
Recommendations on physical
conditioning programs
No recommendations can be made based on the
available evidence.
Recommendations for future
research
Randomized controlled trials
are possibly the only way to control for all the individual and situational variations
and study the contribution of conditioning to injury prevention in various sports.
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