A Research Report submitted to the Faculty of
Health Sciences, University of the Witwatersrand
Gauteng, 2017 / Background
Soccer is a sport that is gaining in popularity in the elite and non-elite populations worldwide.
As a result, the number of injuries in soccer is increasing. Hamstring injuries in particular,
with a reported incidence rate as high as 63%, are of significant concern. Most hamstring
injuries tend to occur during the swing phase of sprinting when hamstring activity is at its
highest. As the speed of sprinting increases, greater mobility in the lumbo-pelvic area is
required to maximise sprinting efficiency. Any abnormal or dysfunctional lumbo-pelvic
movement during this phase could induce pain and hamstring injury. Lumbo-pelvic
movement control dysfunction may therefore indirectly link abnormal lumbar spine
movement to lumbo-pelvic pain and hamstring injury.
The first aim of this study was to compare the performance of the erector spinae, gluteus
maximus, hamstrings (biceps femoris) and quadriceps (rectus femoris) muscles in soccer
players, with and without recent hamstring injuries, while performing isometric contractions,
a functional squat and sprinting. The study’s second aim was to compare lumbo-pelvic
movement control in soccer players with and without recent hamstring injuries.
Method
Thirty soccer players were selected to participate in this study. Fifteen were assigned to the
injured group and 15 to an uninjured group. The injured group comprised players who had
sustained a hamstring injury six months prior to the research and who had partially returned
to training, and the uninjured group comprised players with no recent hamstring injuries and
who were actively involved in full training. Players were matched in respect of age, height,
weight and playing position.
All players gave informed written consent, completed the physical activity, training and
injury questionnaire, and the Oslo hamstring injury questionnaire. Physical tests, which
included isometric contraction of the erector spinae, gluteus maximus, hamstrings (biceps
femoris) and quadriceps (rectus femoris) muscles, a functional squat and a thirty-metre sprint
were done. Muscle activity during these tests was recorded via electromyography (EMG). To
determine the lumbo-pelvic movement control of the players, the dorsal pelvic tilt, waiter’s
bow, one leg stand and prone knee bend tests were used.
Cohen's d (parametric) and Spearman’s correlation coefficient (nonparametric) were used to
calculate the effect size, and the Chi-square test and Fisher’s exact to analyse the lumbopelvic
movement control data. To establish a statistical significance, the p-value of the study
was set at p<0.05.
Results
EMG muscle activity during isometric contractions was lower in the erector spinae muscles
(p=0.04) and biceps femoris muscle (p=0.02) of the injured group. Both these findings were
statistically significant. There was no statistically significant difference in muscle activity
during the functional squat between the study and uninjured groups. The results of the EMG
activity in the thirty-metre sprint were determined to be significant as they demonstrated that
the hamstring muscle (p=0.01) activation in the injured group was decreased in comparison
with the uninjured group.
During the performance of the lumbo-pelvic test, no association was found between the two
groups in the dorsal pelvic tilt and one leg stand. The performance of the waiter’s bow
(p=0.01) and prone knee bend (p=0.004) revealed statistically significant differences between
the study and uninjured groups. The majority of the players in the injured group performed
both of these functional tests incorrectly (WB n=10; PKB n=14).
Conclusion
The study found that the hamstring muscle is at great risk of injury during eccentric
contraction of the hamstring muscles. This can be associated with poor lumbo-pelvic
movement control, as the load on the hamstring muscle is increased to provide intersegmental
stability around the neutral zone, the area of high spinal flexibility. / MT2017
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/23180 |
| Date | January 2017 |
| Creators | Roos, Riali |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf, application/pdf |
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