Samenvatting

Abstract
Introduction: Although there is a lack of scientific evidence, it is still widely believed that pre-exercise stretching
is a quick and effective way to reduce the risk of injury. To determine if stretching is an effective means to
reduce the risk of injury, we first have to look what the effects of stretching are at muscle stiffness, compliance
and how long we need to hold the stretch for.
The main question of this study is: Is pre-exercise stretching an effective means to reduce the risk of injury?
The subquestions are:
1. Which stretch holding time is needed to increase ROM?
2. Is muscle stiffness a risk factor for muscle damage?
3. Does stretching increase muscle compliance?
Methods: The electronic databases used are: Pubmed and Omega. There has been searched using the following
terms and combinations of the terms: stretching, pre-exercise, injury, prevention, muscle and duration. Inclusion
criteria were: articles written in 2000 or later or the most recent known research, stretching had to be done preexercise,
the focus of the research had to be about stretching as a means to prevent injury. The methodological
quality of the articles have been assessed using a Cochrane checklist
Results: Stretch holding time: Roberts, Wilson.4 found that a stretch program with only a 5 seconds stretch
duration is sufficient to increase ROM. They have stretched 3 times a week for 5 weeks. The total stretch time
was 45 seconds.
Muscle stiffness: Malachy et al.5 have found that subjects with stiffer hamstring muscles experienced greater
strength loss, more pain and greater muscle tenderness.
Witvrouw et al.6 found a significant difference in ROM between the injured and uninjured players for the
quadriceps and hamstring muscle. There was no difference in ROM of the adductor and gastrocnemius
Compliance: Mahieu et al.7 found that after 6 weeks of stretching all groups had a significantly improved ankle
dorsiflexion, even the control group.
The passive resistive torque only decreased significantly for the static stretch group and not for the ballistic and
control group.
Cornwell et al.8 found stretching to decrease active stiffness, but no change was found on the static jump height.
Countermovement jump was significantly lower and ROM increased significantly.
Injury prevention: Brooks et al.9 found inconclusive results and Pope et al.10 found no significant effect of
stretching under 1538 army recruits
Conclusion: Stretch holding time: A stretch program with only a 5 seconds stretch duration is sufficient to
increase ROM.
Muscle stiffness: Based on the results in this article we conclude that muscle stiffness is a risk factor for muscle
damage
Compliance: At this moment there isn’t enough evidence to support stretching as an effective means to improve
the compliance of a muscle
Injury: Based on these results there isn’t enough evidence to support stretching as a means to prevent injury.
Recommendations: More research is needed with large populations and also combinations of stretching methods.
Discussion: Most of the results on which this paper is based are from small populations. Research with larger
populations is needed. All of the evidence is for lower limb injuries. No research is done for the upper
extremities. Maybe the influence of muscle stiffness on injury is different in individual muscle groups. This
would mean that stretching only particular muscle groups is effective. The compliance gained by stretching
might be overshadowed by the influence of other risk factors like age and overall fitness, and therefore no
reduction in injury is found.
Malachy et al.5 and Cornwell et al.8 had a short follow up. It is unknown if the examiner was blind for the
allocation with the studies of Malachy et al.5, Mahieu et al.7 and Cornwell et al.8