CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.10 No.5, pp 330-340, 2017
Abstract : Core muscles endurance are important issues in lower extremity injury among football players. This study investigates the relation between core muscles’ endurance and the occurrence of different lower extremity injuries during one season. Eighty-two male football players (mean age 20.69±3.85, weight 76.3±14and height 178±9.6) were tested. After being screened for a season. The prone-bridge, side-bridge, trunk flexion and horizontal back extension hold times were recorded for endurance assessment; in addition the numbers of different lower extremity injuries during the current season. The negative binominal regression method revealed that the maximum holding time for trunk flexor endurance only was significantly related to occurrence of lower extremity injuries (p<0.05). On the other hand the maximum holding time for plank, side plank and trunk extensor endurance were not
significantly related to frequency of lower extremity injuries (p≥0.05).Abdominal muscle
endurance is related to the risk of lower extremity injuries more than plank, side plank and trunk extensor muscles endurance. Abdominal muscles endurance are more important issues in preventing different lower extremity injuries among male football players.
Football (Soccer) is the most popular sport worldwide with around 265 million players 1. It is a sport that uses walking, jogging, running, and sprinting. The most common injury locations in football players are the
2,3,4,5,6
knee (7–32%), ankle (9–31%) and thigh (6–22%) .These injuries include traumatic anterior cruciate ligament (ACL) ruptures to overuse injuries such as patellofemoral pain syndrome, iliotibial band friction syndrome, and femoral, hamstring strain and ankle sprain7,8 .
Hamstring strain injury is one of the most common injuries in sports, and causes significant loss of training and significantly affects the quality of life of injured athletes. Hamstring muscle injury also has a high re-injury rate, which frustrates the injured athletes as well as the clinicians and increases cost of the treatment 9. Anterior cruciate ligament (ACL) tear, is one of the most common knee injuries in sports 10, usually occurring
11,12
in a multitude of sports such as basketball, soccer, handball and tennis . Ankle inversion sprain are amongst the commonest injuries of lower extremities especially in athletes involved in high contact sports. A common complication after ankle sprain is the development of functional instability at the ankle joint and the tendency for the sprain to reoccur, thus resulting in chronic ankle instability 13.
Core stability is defined as the ability to control the position and motion of the trunk over the pelvis to allow optimum production, transfer and control of force and motion to the peripheral segment in integrated athletic activities. Core muscle activity is best understood as the pre-programmed integration of local, single-joint muscles and multi-joint muscles to provide stability and produce motion. This results in proximal stability for distal mobility, a proximal to distal patterning of generation of force, and the creation of interactive moments that move and protect distal joints 14.
The importance of core stability (CS) for injury prevention and performance enhancement has been increased during the recent period with minimal supporting evidence. Even though limited evidence exists, the integration of core stability exercises into injury prevention programs, particularly for lower extremity, is
15,16,17,18,19,20
demonstrating decreased injury rates .
Trunk and hip neuromuscular control measurements have been shown to predict the incidence of knee injury 21. Control and stability of the lumbopelvic region is important in the transfer of forces between the lower limbs and spine. Inability to stabilize the lumbopelvic region during dynamic lower extremity movements could lead to excessive load on joints (14).Lumbopelvic motor control training in elite athletes was shown to increase targeted muscle size, reduce low back pain (LBP) and reduce occurrence and severity of lower limb injuries
22,23,24,25
.
There is only minimal voluntary isometric contractions of trunk musculature are necessary to stabilize the spine, so that muscular endurance along with sensory-motor control are of greater importance than strength
26 27
In athletic tasks, muscle endurance appears to be more important than pure muscle strength. Many
when considering core stability | .Also, | stated that co-activation and coordination of the core muscles rather |
---|---|---|
than strength, provide an ideal core. | ||
28 |
studies have suggested that proper core stability is important for injury prevention, so poor core stability can be a predictor for injury. Poor core stability was reported as a predictor for anterior cruciate ligament injury,
29,30,31,32,33
patellofemoral pain, iliotibial band syndrome, low back pain, and improper landing kinematics . While other studies support the role of core training programs for injury prevention, they do not suggest that they will
30,34
improve physical tasks or improving strength and sport-specific performance .
CS is defined as the ability to control the position and motion of the trunk over the pelvis to allow optimum production, transfer and control of force and motion to the peripheral segment in integrated athletic activities. Core muscle activity is best understood as the pre-programmed integration of local, single-joint muscles and multi-joint muscles to provide stability and produce motion. This results in proximal stability for distal mobility, a proximal to distal patterning of generation of force, and the creation of interactive moments that move and protect distal joints 14.Therapist and trainers have considered CS as an approach for improving sports performance 14, preventing injury. However, these thoughts are not supported by clinical studies. Despite the strong believe in the positive effects of Core Stability Training (CST), there is limited scientific studies have shown direct relationship between stronger core muscles and better athletic performance and injury prevention
35,36
.
The relationship between core stability and injury prevention is also relevant. A study by 21 evaluated trunk displacement and stiffness in response to movement, as well as the ability to determine spatial position of the trunk. The findings were increased knee ligament and ACL injuries occurring in collegiate athletes which increase trunk displacement following a sudden force release and Lateral trunk displacement was illustrated to be the strongest predictor of knee ligament injury21.Over the past several years, the body of literature related to the relationship between core stability and injury prevention has significantly increased. However, this relationship has not been defined yet 37.
Eighty two male football players (mean age 20.69± 3.85, weight 76.3± 14and height 178± 9.6) who volunteered to participate in the study. They were interviewed and screened based on the following inclusion and exclusion criteria:
The volunteered football players were included in the study if they had Body mass index (BMI) was less than 30 kg/m².Age ranging from 18-30 yearswith no previous history of sprain or strain or losing performance in training during the past participation season. 82 players met that criteria and were included in the study. Then we recorded the participants who experienced an injury to one of his lower extremity through the current season. Back and abdominal muscles' strengths of grade five as assessed by manual muscle test. Ankle dorsiflexors and evertotrs strength should of grade five as assessed by manual muscle test.
The volunteers were excluded if they had any history of traumatic fracture of femur, tibia, fibula, foot bones, or of traumatic patellar subluxation or dislocation, or Previous surgery in the knee and hip joints, orknee and hip joints osteoarthritis, or any conditions affect muscle strength: diabetes mellitus, rheumatoid arthritis, a history of any previous back and/or abdominal surgeries and/or diseases , any previously perceived episodes of low back pain one year before being involved in the study. Tightness of the lumbar flexors, lateral flexors or rotators.Tightness of the hip flexors.
Instrumentations:
Assessment of the core endurance was done using
1.1. | The Prone Bridge |
1.2. | The Lateral Bridge |
1.3. | Torso Flexors Endurance |
It includes the following items: participant’s name, age, address, weight, height, body mass index and phone
number.
A universal height and weight scale was used to determine the participant’s height and weight.
Fig (1) height and weight scale
All volunteered players were informed by the purpose of the study and the testing procedure were fully explained and all relevant questions were answered. Then, if the individual agreed on participating in the current study, he signed on informed consent. A brief learning session about the nature of the study, the purpose of study and the tests to be done were provided to each participant.
1 Assessment of Core Stability:
Fig.(2): prone bridge test
The prone bridge is done by supporting the body's weight between the forearms and toes and assesses primarily the anterior and posterior core muscles. It is essential that the athlete keep the pelvis in a neutral position and the body straight. Failure occurs when the athlete loses neutral pelvis and falls into a lordotic position with anterior rotation of the pelvis 38. The total time the athlete was able to lift their pelvis from the table was recorded using a stopwatch.
1.2. Lateral Bridge Test:
Athletes performed the side bridge test as described by McGill et al.,38 as a measure of lateral core muscle capacity, particularly the quadratuslumborum.
The athletes were positioned in right side lying with their top foot in front of their bottom foot and their hips in zero degrees of flexion. The athletes were asked to lift their hips off the treatment table, using only their feet and right elbow for support. The left arm was held across their chest with their hand placed on the right shoulder. The total time the athlete was able to lift their bottom hip from the table was recorded using a stopwatch. McGillet al.,38 previously documented no significant difference between right and left side bridge endurance times. Therefore, the measure for the right lateral core muscles was used for data analysis. Failure occurs when the athlete loses them straight posture and the hip falls toward the table.
1.3. Torso Flexor Endurance Test:
Torso flexors endurance assesses the endurance of trunk flexors muscles in a static manner while subject maintained 60 degrees of trunk flexion against gravity.Testing of the torso flexors were done by timing how long the athlete can hold a position of seated torso flexion. The torso should be flexed at 60° and the knees and hips flexed at 90°. The toes should be secured under toe straps or held by the examiner. Failure occurred when the athlete's torso falls below 60°.
1.4. Torso Extensors Endurance Test:
Testing of the torso extensors can be done with the athlete in a prone position and the pelvis, hips, and knees secured on a table by the therapist.
The upper body was held out straight over the end of the table. Muscle capacity of the posterior core was measured using the modified Biering-Sorensen test McGill 38.The athlete was required to maintain the body in a horizontal position for as long as possible. The total time that the athlete was able to maintain the horizontal position until they touched down on the bench in front of them with their hands was recorded in seconds using a stopwatch. Failure occurred when the upper body falls from horizontal into a flexed position.
Preseason Data Collection.
The therapist obtained written informed consent from each player. Information on previous injuries (within the past 6 months and 1 year) and sports participation (within the past 6 months and 1 year) was collected. Past history, in addition to other medical history, were recorded from the athlete. The therapist completed measurements of height, weight, leg dominance, with all participating players. The leg preferred for kicking soccer ball determined leg dominance.
Any sports injury that resulted in the following: the inability to complete a full session, missing a subsequent session, or medical attention was recorded. The team therapist informed the researcher or the players informed the researcher directly by meeting him or calling him about his injury. If time loss from sports was associated with the injury assessed by the therapist and appropriate treatment was provided
Eighty two male soccer players were participated in the current study without any missing of their injury profile during their playing season. The maximum holding time for plank, sideplank, trunk flexor endurance and trunk extensor endurance tests recorded as independent variables and numbers of injuries were recorded as a dependent variable during the current season. The holding time for each test was listed in Table (1).
The recording of the frequency of lower extremity injuries (number of injury) is considered a count variable we should use passion regression analysis. In our study we used the negative binominal regression method during statistical analysis of our data due to over diversion of passion regression.
There was no significant relation between holding time of plank and number of injuries (p = 0.860). There was no significant relation between holding time of side plank and number of injuries (p = 0.355). There was a significant relation between holding time of trunk flexor endurance test and number of injuries (p = 0.008). Also, There was no significant relation between holding time of, trunk extensors endurance test and number of injuries (p = 0.786) as illustrated in a table (2).
Table (1) Holding Times or Endurance Tests
Minimum N | Maximum | Mean | Std. Deviation | ||
---|---|---|---|---|---|
Frequency of injuries | numberofinjury | 0.00 82 | 6.00 | 1.15 | 1.62 |
TEET | 2.00 82 82 | 325.00 | 84.57 | 49.23 | |
TFET LBT | 43.00 6.50 82 | 275.00 173.30 | 129.44 89.99 | 42.86 32.29 | |
Core endurance | |||||
PBT | 23.70 82 | 154.20 | 64.11 | 26.88 |
TEET : Trunk Extensor Endurance Test TFET : Trunk Flexor Endurance Test LBT : Lateral Bridge Test PBT : Prone Bridge Test Table (2) Negative Binominal Regression showed The Relation Between Variables
TEET : Trunk Extensor Endurance Test TFET : Trunk Flexor Endurance Test LBT : Lateral Bridge Test PBT : Prone Bridge Test
The purpose of this study was to examine the relationship between core muscles endurance measures and risk of different lower extremity injuries among male football players. It was a trial to identify one or a combination of core endurance measures that could be used to identify those individuals who are at increased risk for lower extremity injury. In the current study there was no significant relation between the endurance measures (holding time) for plank, side plank, trunk extensor endurance and the frequency of lower extremity injuries. While there was a significant relation between the endurance measures (holding time) for trunk flexor (abdominal) endurance and lower extremity injuries among male players (P = 0.008) with 95% confidence interval (0.003:0.023).We suggest that trunk muscles weakness reduces the ability of the athletes to stabilize the trunk against the large external forces experienced by these segments during athletic maneuvers especially the anterior abdominal muscles.Our finding agree with previous studies that clarified that CS has been considered an important issue for maintaining dynamic joint stability throughout the kinetic chain that extends from the
39,40
foot to the lumbar spine .Alteration of neuromuscular activation patterns in the core and the lower extremity
41,42
have been documented in patients with joint injuries that are distant from the affected musculature . The injury-related neural effect on muscle activation can occur in either a distal-to-proximal or proximal-to-distal direction. Lower extremity dysfunction increases susceptibility to low back injury 29and susceptibility to lower
21,41,43
extremity injury appears to be increased by low back dysfunction.
Suboptimal endurance of the core muscles has been associated with impaired neuromuscular control of
the body’s center of mass, inhibition of lower extremity muscles, and elevated risk for lower extremity
injury. Early fatigue in core muscles also may be a cause in predisposing athletes to injury, as fatigue of the abdominal muscles has been found to be a contributor to hamstring injuries 45. There also may be gender differences in whether CS plays a role in risk of injury, as suggested by 21 who found that increased trunk displacement and decreased proprioception on testing predicted knee ligament injury for women, although these findings were not predictive in men.
The current study found that core endurance measures of abdominal muscles are predictors of injury status over the course of one athletic season for football male players. However, the trunk flexors are only some of elements of core stability, and other elements of core stability not included in this study that may add to the predictive value of the regression equation. Core stability is dependent on motor control and muscular capacity of the lumbo-pelvic-hip complex.Decreased perception of rapid body core displacements during sport-specific tasks may interfere with the ability to generate adequate corrective responses of the core muscles, which requires lower extremity joints to displace to a greater extent to maintain postural stability40.Any delay in activating muscles that span the displaced joints is likely to increase injury susceptibility.The time an individual can sustain a static body position that involves loading of the core musculature may be valuable for quantifying the risk for injury to either the core or the lower extremity 46.
Greater rectus abdominis, external oblique, and internal oblique activity occurs in the side bridge compared with the crunch exercise 47. No significant difference in rectus abdominis activity were found during prone and side bridge, but significantly greater external oblique and lumbar paraspinal activity was seen in the side bridge compared with the prone bridge 48. The crunch and side bridge are effective in activating the internal oblique and transversusabdominis49while the side bridge is effective in recruiting the quadratuslumborum 50.
Side bridge on toes and knees demonstrated significantly less upper and lower rectus abdominis, internal oblique, and latissimusdorsi activity as well as rectus femoris activity but significantly greater lumbar paraspinal activity compared with supine and prone position exercises 51.
Our results did not come with agreement with both Zazulak et al.,21 who reported that lateral trunk control was a predictor of knee injury risk, and Hewett et al.,52 who used observations of noncontact ACL injury events to conclude that lateral trunk position may be an important factor in the ACL injury mechanism. Leetun et al., 32 found that the performance in the side bridge test was not a risk factor for low back and LL injuries during a season in basketball and track and field athletes which support our results as we limited our sample to male football players only.
Vleeming and colleagues 53noted that the gluteus maximus and contralateral latissimusdorsi provide a perpendicular force to stabilize the Sacroiliac (SI) joint. The SI joint activates the gluteus maximus, quadratuslumborum, and multifidus54.So, the SI joint provides lumbopelvic stabilization for locomotion and posture. Changes in the loading of the SI joint may alter the activation of stabilizing muscles. Contraction of the TransversusAbdominis (TrA) has been shown to increase SI joint stability 55.Preactivation of the multifidus and internal oblique muscles contributes to compression of the SI joint necessary for lumbopelvic stabilization during load transfer from double-to single-leg stance56.
The cause of groin injury may not be the groin area itself but rather the supporting areas of the abdominal core and hip. Athletes with chronic groin pain demonstrate delayed activation of the TrA compared
57 58
with controls .Holmich et al. utilized a successful gradual strengthening and conditioning program for weak abdominal muscles and hip adductors in athletes with chronic groin pain. A recent study reported that a progressive agility training program with trunk stabilization exercises is more effective than an isolated hamstring stretching and strengthening rehabilitation program 59.
Abdominal muscle endurance is related to the risk of lower extremity injuries more than plank, side plank and trunk extensor muscles endurance. Abdominal muscles endurance are more important issues in preventing different lower extremity injuries among male football players.
The primary limitation of this study was the relatively small number of injuries sustained by the football players during a surveillance period that was limited to a single season.Also a limitation of this study was the operational definition of an injury as any core or lower extremity sprain or strain.The results of this study made many questions for further studies. For example, future studies may use measures that assess core muscles function during closed chain activities. Further, these tests may not reflect the degree to which the muscles are recruited by the athletes during athletic participation. Future studies also should add a dynamic test of lower extremity alignment during a closed kinetic chain activity such as the single leg step down test.
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