Hamstring Muscle Strains A Common Injury Physical Education Essay

Published Date: 23 Mar 2015

Hamstring muscle strains are one of the common problems for many athletes which results in significant loss of on-field time. These injuries tend to heel slowly. Hamstring injuries are more common in sprinters and athletes, as they perform high-speed skilled movements. Once hamstring injury occurs, without proper rehabilitation and rest the athlete is at high risk for recurrence.

Some pose complicated challenges remains after the injury rehabilitation, when returning the athletes quickly and safely to participate in sports. The most common soft tissue injuries in thigh occur in hamstrings; particularly at the musculo-tendinous junctions (Fox 1986, King and Robertson 1986). A 4 year study was conducted of injury rates for Memphis state university football team. The study showed that hamstring strains were the third most common injuries after knee and ankle injuries during sports.

The re-injury rate was 12% for hamstring strains when compared with an average re-injury rate of 7% for all other injuries. The injury recurrence is at highest risk during first 2 weeks of return to sports. Moreover, following return to sport nearly one third of these injury recurrences appear within the first year. An author, in his study reported that out of 30 sprinters 15 suffered from preceding hamstring strains.

The commonly utilized rehabilitation programs for hamstring injuries may be insufficient at resolving reduced tissue extensibility, possible muscular weakness and altered movement patterns associated with injury suggests the high re-injury rates. The primary objective of the rehabilitation program for hamstring is to restore the athlete with the level of activities previously carried out with minimal risk of recurrence of the injury of their participation in sports.

ANATOMY

There are 3 hamstring muscles present in the posterior thigh: the semitendinosus, semimembranosus and biceps femoris. The semitendinosus originates at the ischial tuberosity and gets inserted at the pes anserine; the semimembranosus gets origin from the ischial tuberosity and inserts at the posterior medial tibia. The biceps femoris has two heads; a long head which originates at the ischial tuberosity and a short head originate at the postero-lateral femur. Both heads of biceps femoris gets inserted into the head of the fibula. The hamstring muscle acts as knee flexors and hip extensors.

ANATOMY OF HAMSTRING MUSCLE

MECHANISM OF INJURY:

A muscle is commonly strained or torn during rapid acceleration or deceleration movements. The most implicated cause of hamstring strains is the imbalance between the quadriceps and the hamstring muscles. The hamstring muscle group is a two joint muscle and thus the anatomical configuration of the muscle group is at increased risk and more susceptible for strains.

Clanton and Coupe (1998) describes about mechanism of injury. The underlying mechanism for hamstring strains is suggested to be the increased force generated during eccentric action of muscle as opposed to a concentric contraction suggested as. The most common 2 factors in hamstring injury are lack of adequate flexibility and strength imbalances in hamstring muscle group.

Eccentric contractions are characterized by active lengthening of muscle fibres. In eccentric contraction, as the speed of contraction increases the force of contraction also increases as well. Conversely, during concentric contractions shortening of muscle fibres occurs and inverse relationship between the speed and force of contraction. During late swing phase, the hip is flexed and the knee is extended which is suggested for injuries to occur. In a high speed running, the hamstring strain occurs during terminal swing phase of gait cycle. The greatest musculo-tendon stretch is incurred by the biceps femoris muscle, which is more often injured than the other two hamstring muscles (semimembranosus and semitendinosus) during high speed running.

MECHANISM OF INJURY

HAMSTRING MUSCLE INJURY

CLASSIFICATIONS OF MUSCLE INJURY:

Injuries to muscles and tendons of the hamstrings are generally classified into three categories. These injuries are mentioned as: the strains of first, second and third grade.

A first degree strain is less severe. It is the result of a minor stretch of the muscles and tendons, and is accompanied by a slight pain, stiffness and swelling. In general, very little loss of function is present after a first degree strain.

A second degree strain is the result of both stretching and some tearing of muscles and tendons. There is an increased pain and swelling accompanied with a strain in the second degree. A moderate loss of function of that exacting muscle will be present.

A third degree strain is the most rigorous of the three degrees of strains. Complete tear or rupture of one or more of the muscles and tendons is said to be third degree strain. It results in severe pain, massive swelling and gross instability.

GRADES OF MUSCLE STRAIN

RISK FACTORS:

While an athlete performing running or jumping activities in sport, hamstring injuries happens usually as a result of rapid acceleration or deceleration movements. There are some main modifiable risk factors which include:

* In-adequate warm-up leading to muscle fatigue

* Muscle tightness

* Imbalance of muscular strength with low hamstring to quadriceps ratio

* Previous injury.

SYMPTOMS AND SIGNS:

In Grade 1 (Mild) : Local pain over posterior thigh, mild spasm, swelling, ecchymosis, local tenderness, mild pain on passive stretch and active contraction of the involved muscle, minor disability with loss of function and strength.

In Grade 2 (Moderate) : Local pain, moderate spasm, swelling, ecchymosis, local tenderness, moderate pain on passive stretch and active contraction of the involved muscle, moderate disability with impaired muscle function and strength.

In Grade 3 (Severe): Severe pain, severe spasm, swelling, ecchymosis, haematoma, tenderness, loss of muscle function, palpable defect may be present.

STRETCHING:

Stretching is believed to increase the range of motion around a joint through a decrease in visco-elasticity and an increase in compliance of muscle. By improving force absorption for a given length of muscle, thereby making the muscle is limited as the positive effect was demonstrated in only minor injuries.

Stretching exercises can be carried out as an individual training to enhance the flexibility of a muscle or as a warm-up planned to avoid injury and prepare the body for workout to pursue. Stretching gently lengthens the muscles before and after other exercises and helps to improve tissue elasticity and flexibility. It is suggested that a person should warm-up previous to stretching to enhance the blood flow. In turn this improved blood circulation makes the muscles more flexible. It is also not compulsory that all static stretches are supposed for 15 seconds at least prior to being released in order to stretch the muscle efficiently.

STRENGTHENING EXERCISES:

The development of muscle strength is an integral component of most rehabilitation or conditioning programs for individuals of all ages and all ability levels.

Strengthening of the hamstrings is an essential role in rehabilitation after injury to obtain the muscles back to their complete strength. This strengthening program will also facilitate to prevent anymore upcoming injuries. The most common adaptation to heavy resistance exercise is an increase in the maximum force-producing capacity of muscle, that is, an increase in muscle strength, primarily as the result of neural adaptations and an increase in muscle fibre size.

PROGRESSIVE AGILITY EXERCISES:

Agility training is a great way to help develop speed as well as becoming agile. This kind of method in training an athlete is enormously beneficial.

The benefits of agility training can certainly give a progression to any athletes in their overall performance. The skill to execute on the field and yet off the field is also improved. It also increases the running speed because running is the supreme foundation of all athletics. These agility exercises are also worn to increase the speed and quickness in all sports kind. These agility training vary from conventional speed training in that they integrate a lot more lateral movement.

TRUNK STABILIZATION EXERCISES:

Trunk stabilization exercises give strong, flexible trunk muscles that support well-aligned bones. It refers to progressive conditioning of the musculature of the pelvis and hip girdle, lumbar spine, abdominal region and peri-scapular musculature particularly as the use of these muscles relates to the performance of specific dynamic tasks involving the trunk of extremities. These exercises will strengthen the lower back and abdomen. Strengthening the core is essential to prevent all forms of injury around the lower back area. The concept of core stability has a theoretical basis in the treatment and prevention of various musculo-skeletal conditions. Many therapists now include a component of core stability training in the rehabilitation of a wide variety of lower limb injuries.

This had led some physical therapists to make use of a variety of trunk stabilization and progressive agility exercises for hamstring rehabilitation programs.

OPERATIONAL DEFINITIONS:

Muscle Strain:

A muscle strain is defined as an excessive stretch, which leads to muscle fibre damage and disrupts the integrity of related vascular and connective tissue structures.

Stretching:

Stretching is a form of physical exercise in which a specific skeletal muscle (or muscle group) is deliberately elongated to its fullest length in order to improve the muscle's felt elasticity and reaffirm comfortable muscle tone.

Strengthening:

Strength training is defined as a systematic procedure of a muscle or muscle group lifting, lowering or controlling heavy loads (resistance) for a relatively low number of repetitions or over a short period of time.

Agility:

Agility is the ability to perform a series of explosive power movements in rapid succession in opposing directions.

Trunk Stabilization:

There is no formally endorsed definition of trunk stabilization. It refers to the balanced development of the deep and superficial muscles that stabilize, align and move the trunk of the body, especially the abdominals and muscles of the back.

NEED FOR THE STUDY:

The athlete returning to sport at previous level of functional performance with a minimal risk of injury recurrence is the primary goal of a rehabilitation program following a hamstring strain injury. The high re-injury rate may be due to the use of inappropriate criteria for determining suitability for return to sport or, alternatively, that traditional rehabilitation methods are insufficient for reducing risk for re-injury.

The need for the study was to determine that improved coordination of the lumbo-pelvic region allows the hamstrings for its optimal function at safe lengths and loads during athletic movement, thereby reducing injury risk.

AIM:

The aim of this study is to compare the effectiveness of Stretching and Strengthening program with Progressive agility and trunk stabilization program in the rehabilitation of acute hamstring strains.

OBJECTIVES:

To compare the effectiveness of two rehabilitation programs for acute hamstring strains by evaluating the relationship between functional testing performances.

HYPOTHESIS:

Null hypothesis:

There is no significant difference between the Stretching and Strengthening program against Progressive agility and trunk stabilization program in the functional testing performance of the athletes for acute hamstring strains on the day of return to sports.

Alternate hypothesis:

There is a significant difference between the Stretching and Strengthening program against Progressive agility and trunk stabilization program in the functional testing performance of the athletes for acute hamstring strains on the day of return to sports.

2. REVIEW OF LITERATURE

Bryan C. Heiderscheit, Marc A. Sherry, Amy Silder, Elizabeth and Darryl G. Thelen (2010) In a study says that there is a mounting evidence that the risk of re-injury can be minimized by utilizing rehabilitation strategies that incorporate neuromuscular control exercises and eccentric strength training, combined with objective measures to assess musculo-tendon recovery and readiness to return to sport.

Mason DL.Dickens V.Vaila(2007) In their study suggested that there is only limited evidence for rate of recovery can be increased with an increased daily frequency of hamstring stretching exercises. While managing a hamstring injury, the lumbar spine, sacroiliac and pelvic alignment along with the postural control mechanisms also must be concentrated. Lumbar stability and pelvic muscle control may also be a factor in reducing the rate of recurrence of hamstring injury.

G.Verrall, J.Slavotinek and P.Barnes(2005) Increasing the amount of anaerobic interval training, stretching whilst the muscle is fatigued and implementing sport specific training drills resulted in a significant reduction in the number and consequences of hamstring muscle strain injuries.

Thelen. D.G, E.S. Chumanov, M.A. Sherry and B.C. Heiderscheit(2006) In this article shows that hamstring strains are a common and recurrent injury among sprinting athletes and describes about the mechanics of hamstring injury and the influence of muscle co-ordination on hamstring mechanics. These observations are important for establishing effective injury prevention and rehabilitation programs.

Clanton TO, Coupe KJ (1998) Hamstring strains are among the most common injuries in athletes. This muscle injury occurs mostly at the myo-tendinous junction, when the force is concentrated. Concurrent pain-free stretching and strengthening exercises are essential to regain flexibility and to prevent further injury.

Gabbe BJ, Brason R and Bennell KL (2006) Evaluated the effectiveness of a pre-season eccentric training program on 220 players for preventing hamstring injuries. Five exercise sessions are completed over 2 weeks. Their finding suggests that a simple program of eccentric exercise could reduce the incidence of hamstring injuries.

David J.Magee, James E.Zachazewski, William S.Quillen (2009) Strain or overload of the hamstring tissues also may be due to a pelvic alignment fault or mal-alignment that changes the length/tension relationship of the hamstrings. Athletes with hamstring strain often show an anterior in-nominate tilt on the affected side. Rehabilitation of hamstring strains using progressive agility and trunk stabilisation exercises has been found to be more effective than a program emphasizing isolated hamstring stretching and strengthening and enable to return to activity more quickly than those treated with more conservative measures.

Robert Donatelli (2007) According to the clinical experience of the author, patello-femoral pain, hamstring strains, lateral hip pain results from lower quadrant core muscle deficits. Leerun et al demonstrated that core stability played an important role in injury prevention. Mascal et al reported that strengthening the hip, pelvis and trunk musculature resulted in a significant improvement in lower-extremity kinematics and ability to return to their sporting activities.

Thomas E.Hyde, Marianne S.Gengenbach (2007) Muckel states that hypomobility of the lower lumbar spinal segments is a cause of repetitive hamstring strains. Anterior pelvic tilt causing increased stretching of the hamstring also has been incriminated as a cause.

Peter Brukner and Karim khan (2007) Core stability program have shown the positive benefit in the management of sporting injuries. Many physiotherapists now incorporate an element of core stability program in rehabilitation of a wide variety of lower limb injuries and prevention of various musculoskeletal conditions.

Paul Gamble(2009) Single-leg hop tests of the type of vertical jump test have seen application in the rehabilitation setting to evaluate functional performance of injured and uninjured leg.

Agre JC (1985) Many of the recurrent injuries to the hamstring musculo-tendinous unit are the result of inadequate rehabilitation following the initial injury. The treatment for hamstring injuries should include training to maintain and improve strength, flexibility, endurance, co-ordination, and agility.

Hopper DM, Strauss GR, Boyle JJ, Bell J(2008) The functional hop performance in subjects with an ACL reconstruction and the hop tests results showed different levels of imposed demands on the knee that could be used to assess functional recovery and readiness to resume sport.

Andrea Reid, Trevor B Birmingham, Paul W Stratford, Robert Giffin (2006) conducted a study with 42 patients during rehabilitation after ACL reconstruction. The results show that the described series of hop tests provide a reliable and valid performance based outcome measures. These results sustain the utilization and facilitation in interpretation of hop tests for research and clinical practice.

JW Orchard, P Farhart, C Leopold (2004) suggests that the lumbar spine region pathology is a factor in some of the players who find that they have recurrent hamstring and calf musculo-tendinous injuries despite regular preventing maintenance. This brief report prompts us to consider lower lumbar pathology as a source of hamstring and calf problems (probably strains).

Croisier JL (2004) The risk factors which are examined in the literature have been associated with injury. Inadequate warm-up, invalid structure and the content of training, muscle tightness or weakness, agonist/antagonist imbalances, underestimation of an extensive injury and incomplete or aggressive rehabilitation are said to be most likely.

Malliaropoulos N, Papalexandris S, Papalada A, Papacostas E (2004) a total of 80 athletes with hamstring muscle strains were recruited in the study and the effects of stretching in rehabilitation of hamstring injuries were assessed. The results imply that stretching is of great value in treating muscle strain injuries in that it improves the effectiveness of the rest rehabilitation program.

Young W, Russell a, Burge P, Clarke a, Cormack S, Stewart G (2008), In a study determined the relationships between split times within sprint tests over 30m and 40m. They suggested that sprint tests over 30m and 40m can be conducted to provide information about independent speed qualities in athletes and concluded that this test can be used to estimate maximum speed capabilities.

Allen Hedrick, Lt. Jason Sanderson (1996) evaluated the effectiveness of training program using heavy resistance in improving vertical jump ability. Many strength and conditioning programs use the vertical jump test to measure the physiological adaptations from the training. Vertical jump testing is commonly used to measure improvements in the vertical jump for sports and as a general measure of lower body power in sports that requires high levels of lower body power.

Bill foran (2001) functional performance is a representation of actual efficiency through specific testing of gross performance (power, speed, etc). 40 yard dash speed represents the efficiency of the body. It allows the athlete to demonstrate the ability to store energy, efficiency, co-ordination and momentum management.

3. MATERIALS AND METHODS

MATERIALS (TOOLS)

ƒ˜ Stop watch

ƒ˜ Measuring tape

Cone markers

Chalk or Ink

ƒ˜ Thera-bands

Free weights

Couch

Ice packs

Stationary bike

ƒ˜ Data collection sheet and recording sheet

METHODOLOGY

3.1 STUDY DESIGN

An Experimental study design of a pre-test and post-test.

24 athletes with an acute hamstring strain were randomly assigned to 2 rehabilitation groups.

Group A - 12 athletes were assigned to the protocol consisting of static stretching, isolated progressive hamstring resistance exercise and icing (STST group).

Group B - 12 athletes were assigned to the program consisting of progressive agility and trunk stabilization exercise and icing (PATS group).

3.2 STUDY SETTING

This study was carried out with the students in sports team of Sri Ramakrishna Matriculation School, Sri Ramakrishna Institute of Paramedical Sciences and SNR College, Coimbatore.

3.3 SAMPLING

All acute hamstring strain patients were included in this study, hence this will be a simple random sampling.

Each group were assigned with 12 Athletes.

A sample of 24 Athletes were randomly selected and divided into Group A (STST group) and Group B (PATS group).

Both groups were evaluated after the rehabilitation programs for their functional testing profile by hop test for height and sprint test on the day of return to sports.

3.4 DURATION OF THE STUDY

This study was carried out for the period of one year.

3.5 DURATION OF THE TREATMENT

Group A

Phase I - 40 minutes each session, 2 sessions per day.

Phase II - 60 minutes each session, 2 sessions per day.

Group B

Phase I - 40 minutes each session, 2 sessions per day.

Phase II - 60 minutes each session, 2 sessions per day.

3.6. INCLUSION CRITERIA

¶ 14 - 22 yrs of age

¶ Only males

¶ Acute hamstring strains (within past 10 days)

¶ Only first and second degree of injury

3.7 EXCLUSION CRITERIA

¶ Less than 14 yrs or more than 22 yrs of age

¶ Females

Non- acute hamstring injuries

Complete muscle disruption (Third degree injury)

Avulsion injuries

Recent other lower extremity injuries

Inguinal or femoral hernia

Radiculopathy

History of malignant disease

Incomplete healing

Rehabilitation of pelvis or lower extremity features

Nerve entrapment

Lack of daily compliance

Posterior thigh pain not consistent with hamstring

Any other impairment limiting participation in rehabilitation program.

3.8 PARAMETERS OF THE STUDY

a) Hop test for height (in centimetres).

b) Sprinting test (in seconds).

3.9 TECHNIQUE

Group A:

Athletes received the protocol consisting of static stretching, isolated progressive hamstring resistance exercise and icing.

Group B:

Athletes received the program consisting of progressive agility and trunk stabilization exercise and icing.

3.10 STATISTICAL TOOLS

In this experimental study, statistical method was used to show the effectiveness of functional testing profile in Group A and Group B was the dependent 't' test.

The dependent 't' test was calculated to find the difference between pre test and post test within the group, using the formula

Dependent 't' test =

Where,

d = Difference of pre test and post test values.

N = Number of patients

Then the combined standard deviation is calculated using the formula

Combined standard deviation,

S =

Where,

X1 = Difference of post test values and pre test values of Group A

= Mean difference of Group A

X2 = Difference of post test values and pre test values of Group B

= Mean difference of Group B

n1 = Number of patients in Group A

n2 = Number of patients in Group B

With the combined standard deviation value 'S' obtained, and from the values of Group A and Group B, the independent 't' test is performed to show the effectiveness. The obtained independent 't' test values is compared with 22 degrees of freedom of two tailed table value. If the 't' value is greater than table value of 22 degrees of freedom, we can reject the null hypothesis and accept the alternative hypothesis and show the effectiveness of the study.

Independent 't' test was performed with the formula.

Independent 't' test =

Where:

= Mean difference of Group A

= Mean difference of Group B

S = Combined standard deviation

n1 = Number of patients in Group A

n2 = Number of patients in Group B

4. TREATMENT TECHNIQUE

1. STRETCHING and STRENGTHENING (STST) GROUP:

The 4-phase program theorized that progressive stretching and strengthening of the injured tissue would help to remodel and align collagen fibres in the scar tissue. The acute phase (2-4 days) consisted of control of inflammation and early motion of the lower extremity in the sagittal plane. The sub acute period consisted of stationary biking, isolated hamstring progressive resistance exercises and pain-free stretching.

The re-modeling phase consisted of continued, isolated, hamstring progressive resistance exercises (PREs), with the addition of eccentric exercise and continued hamstring stretching. The functional phase included jogging, sprinting, sport-specific drills and continued hamstring strengthening and stretching.

Phase 1

Intensity

Low to moderate

Duration

40 minutes

ISOLATED HAMSTRING STRETCHING

Treatment protocol

Stationary biking with no resistance - 10 mins.

Supine hip flexion with knee extension stretch - 4Ã-20 sec.

Standing hip flexion with knee extension stretch with slow side to side rotation during stretch - 4Ã-20 sec.

Contract-relax hamstring stretch in standing with foot on stool - 4Ã-10 sec contraction, 4Ã-20 sec stretch.

Sub-maximal isometric hamstring sets - 10 repetitions.

Icing in long sitting for 20 mins.

Progression criteria:

Athletes were progressed from exercises in phase 1 to exercise in phase 2 when they could walk with a normal gait pattern and do a high knee march in place without pain.

Phase 2

Intensity

Moderate to high

Duration

60 minutes

STATIONARY BIKING

PRONE LEG CURLS

Treatment protocol:

Stationary biking - 15 mins.

Moderate velocity walk - 5 mins.

Supine hip flexion with knee extension stretch - 4Ã-20 secs.

Standing hip flexion with knee extension stretch with slow side to side rotation - 4Ã-20 secs.

Prone leg curls with ankle weight for resistance - 3Ã-10 repetitions.

Hip extension in standing with knee straight using theraband resistance - 3Ã-10 repetitions.

Non - weight bearing foot catches - 3Ã-30 secs.

Icing for 20 mins (only if there is any local fatigue or discomfort).

ICING IN LONG SITTING

2. PROGRESSIVE AGILITY and TRUNK STABILIZATION (PATS) GROUP:

Some other authors have described similar programs. As the pelvis is the origin attachment site for the hamstring muscles, it has been suggested that neuromuscular control of the lumbo-pelvic region, including anterior and posterior pelvic tilt, is needed to create optimal function of the hamstrings in sprinting and high-speed skilled movement. Changes in pelvic position could lead to changes in length tension relationships or force - velocity relationships.

This has led some clinicians to utilize various trunk stabilization and progressive agility exercises for hamstring rehabilitation programs.

Phase 1

Intensity

Low to moderate

Duration

40 minutes

Treatment protocol

Side stepping - 3Ã-1 min.

Grapevine stepping in both directions - 3Ã-1 min.

Steps forward and backward over a tape line while moving sideways - 2Ã-1 min.

Single leg stand progressing from eyes open to eyes closed - 4Ã-20 secs.

Prone abdominal body bridge - 4Ã-20 secs.

Supine Extension Bridge - 4Ã-20 secs.

SIDE STEPPING

GRAPEVINE STEPPING

Side Bridge - 4Ã-20 secs on each side.

Icing in long sitting for 20 mins.

Progression criteria:

Athletes were progressed from exercises in phase 1 to exercise in phase 2 when they could walk with a normal gait pattern and do a high knee march in place without pain.

Phase 2

Intensity

Moderate to high

Duration

60 minutes

Treatment protocol

Side stepping - 3Ã-1 min.

Grapevine stepping - 3Ã-1 min.

Steps forward and backward while moving sideways - 2Ã-1 min.

Single leg stand windmill touches of repetitive alternate hand touches - 4Ã-20 secs.

Push-up stabilization with trunk rotation - 2Ã-15 repetitions on each side.

Fast feet in place - 4Ã-20 secs.

Proprioceptive neuromuscular facilitation trunk pull-downs with theraband to the right and left - 2Ã-15 repetitions.

PRONE ABDOMINAL BODY BRIDGE

SUPINE EXTENSION BRIDGE

SIDE BRIDGE

Icing for 20 mins (if any symptoms of local fatigue or discomfort are present).

Criteria for return to sport:

Subjects were allowed to return to sports when they demonstrated 5/5 strength when manually resisting knee flexion in prone with the hip in neutral extension, had no palpable tenderness along the posterior thigh and when they demonstrated subjective readiness after completing agility and running tests.

5. DATA ANALYSIS AND INTERPRETATION

The calculations were tabulated for easier statistical calculations and better comprehension. The pre test and post test values of the functional testing profile are obtained by hop test for height and sprinting test were as follows:

6. RESULTS

The functional performance between pre-test and post-test of the individuals within the same group are calculated by using dependent 't' test. For sprinting test, the mean difference obtained for group A is 2.27 and standard deviation is 0.471. Mean difference of group B is 2.65 and standard deviation is 0.393. In hop test for height, the pre and post test values are compared within the group and mean difference of group A is 13.6, where the standard deviation is 1.61. Mean difference of group B is 15.2 and its standard deviation is 1.94.

Performance on the functional testing profile was compared between the Stretching and strengthening program and progressive agility and trunk stabilization program and the t values are calculated using Independent 't' test. In sprinting test, the calculated 't' value is 2.18 with 22 degrees of freedom is greater than the table value, where p=0.05 respectively. In hop test for height, the 't' value calculated is 2.16 with 22 degrees of freedom which is greater than the table value gives p=0.05. Hence, The p value is 0.05 in both sprinting test and hop test for height, it shows statistically significant difference between the two groups in their functional testing profile.

7. DISCUSSION

The purpose of this study is to show the effectiveness of STST group and PATS group for acute hamstring strains. In this study the rate of re-injury is higher in group of athletes performing hamstring stretching and strengthening exercises, as compared to a group performing progressive agility and trunk stabilization exercises after return to sport. The findings in this study shows that functional performance tested on the day of return to sports between STST group and PATS group showed statistically significant differences.

Orchard and Best suggests the early loading of the muscle-tendon unit to avoid secondary atrophy. The progressive agility and trunk stabilization program used in this study controls the early range of motion for dynamic activities by controlling the direction of movement. Frontal plane movements will not increase the length of the hamstring muscle-tendon unit as much as sagittal plane movements. The controlled direction of movement permits early retraining of quick changes in agonist and antagonist muscle contractions of the muscles that control hip and pelvis movement.

Some other authors have hypothesized that the ability to control the lumbo-pelvic region during higher speed skilled movements may prevent hamstring injury. Progressive agility and trunk stabilization drills do involve a combination of concentric, eccentric and isometric contractions of the hamstring muscles in various length-tension positions.

Statistical analysis of the functional testing profile between individuals in the group A (STST group) and group B (PATS group), P values based on independent 't' test are 0.05 respectively, which shows statistically significant between two groups. Hop tests for the injured limb are measured in cms and sprinting tests are measured in seconds. This study has recognised a limitation that, there is no direct evidence that PATS group had improved the functional performance of the individuals because of improved neuromuscular control or trunk stabilization.

8. SUMMARY AND CONCLUSION

Based on the results from the data analysed, it is concluded that the rehabilitation program consisting of progressive agility and trunk stabilization exercises is effective in promoting the better functional performance in athletes on the day of return to sports than athletes those who completes more traditional isolated stretching and strengthening exercise program, who have sustained an acute hamstring strain.

Hence, in this study the null hypothesis is rejected.

9. LIMITATIONS

The sample size of the study is small.

The duration of the study is short.

Only the functional testing profiles between the two groups have been assessed.

10. RECOMMENDATIONS

Similar study can be conducted with large samples and in longer study duration.

In the similar study re-injury rates of athletes between two groups can be evaluated.

Similar study can be conducted in other lower limb injuries as well.

The present study may be repeated by selecting of subjects belonging to other age groups.

REFERENCES:

BOOKS:

T.S.Ranganathan, "HUMAN ANATOMY", 5th edition.

David J. Magee, "ORTHOPAEDIC PHYSICAL ASSESSMENT", 4th edition.

S. Brent Brotzman, Kevin E.Wilk, "CLINICAL ORTHOPAEDIC REHABILITATION", 2nd edition.

Carolyn Kisner, Lynn allen colby, "THERAPEUTIC EXERCISE" foundations and techniques 5th edition.

Peter Brukner and Karim Khan, "CLINICAL SPORTS MEDICINE", 3rd edition.

Thomas E.Hyde, Marianne S.Gengenbach, "CONSERVATIVE MANAGEMENT OF SPORTS INJURIES",(2007).

David J.Magee, James E.Zachazewski, William S.Quillen, "PATHOLOGY AND INTERVENTION IN MUSCULOSKELETAL REHABILITATION", (2009).

Robert Donatelli, "SPORTS-SPECIFIC REHABILITATION",(2007).

Paul Gamble, "STRENGTH AND CONDITIONING FOR TEAM SPORTS: SPORT-SPECIFIC PHYSICAL PREPARATION FOR HIGH PERFORMANCE", (2009).

Bill foran, "HIGH PERFORMANCE SPORTS CONDITIONING", (2001).

ABSTRACTS:

Marc A. Sherry, Thomas M.Best, "A comparison of 2 rehabilitation programs in the treatment of acute hamstring strains", Journal of orthopaedic and sports physical therapy (2004; 34).

Osita Hibbert, Krystie Cheong, Andrew Grant and Trevor Moizumi, "A systemic review of the effectiveness of eccentric strength training in the prevention of hamstring muscle strains in otherwise healthy individuals", NAJSPT ,(2008;May).

Bryan C. Heiderscheit, Marc A. Sherry, Amy Silder, Elizabeth and Darryl G.Thelen, "Hamstring strain injuries: Recommendations for diagnosis, Rehabilitation and injury prevention", Journal of orthopaedic sports physical therapy, (2010; Feb).

Mason. DL, Dickens V.Vaila, "Rehabilitation of hamstring injuries" ,Cochrane database systemic review,(2007;Jan).

Darryl G.Thelen, Elizabeth S.Chumanov, Marc A.Sherry and Bryan C.Heiderscheit, "Neuro-musculoskeletal models provide insights into the mechanisms and rehabilitation of hamstring strains", Exerc. Sport sci. Rev., Vol.34.

Gabbe BJ, Brason R and Bennel KL, "A pilot randomised controlled trial of eccentric exercise to prevent hamstring injuries in community level Australian football", Journal of sci. med. Sport (2006; May).

G.Verrall, J.Slavotinek and P.Barnes, "The effect of sports specific training on reducing the incidence of hamstring injuries in professional Australian rules football players", BJSM (2005; Jun).

Agre JC, "Hamstring injuries, proposed aetiological factors, prevention and treatment", Sports med.,(1985;Jan).

Clanton TO, Coupe KJ, "Hamstring strains in athletes: Diagnosis and treatment", J.Am.Acad.Orthop.Surg.,(1998;Jul).

Hopper DM, Strauss GR, Boyle JJ, Bell J, "Functional recovery after anterior cruciate ligament reconstruction: A longitudinal perspective", Archives of Physical medicine and Rehabilitation, (2008;Aug).

Andrea Reid, Birmingham TB, Stratford PW, Giffin JR, "Hop testing provides a reliable and valid outcome measure during rehabilitation after anterior cruciate ligament reconstruction", Journal of American physical therapy association,(2006;Nov).

JW Orchard, P Farhart, C Leopold, "Lumbar spine region pathology and hamstring, calf injuries in athletes: Is there a connection", BJSM (2004).

Croisier JL, "Factors associated with recurrent hamstring injuries", Sports med., (2004).

Malliaropoulos N, Papalexandris S, Papalada A, Papacostas E, "The role of stretching in rehabilitation of hamstring injuries: 80 athletes follow-up", Med. Sci. sports exerc., (2004:May).

Young W, Russell A, Burge P, Clarke A, Cormack S, Stewart G, "The use of sprint tests for assessment of speed qualities of elite Australian rules footballers", Int. J. Sports physiol. Perform., (2008;Jun).

Allen Hedrick, Lt. Jason C.Anderson, "The vertical jump: A review of the literature and a team case study", National strength and conditioning association, (1996; Feb), vol.18.

APPENDIX

CONSENT TO PARTICIPATE VOLUNTARY IN A RESEARCH INVESTIGATION

Department of Physiotherapy

Sri Ramakrishna institute of paramedical sciences, Coimbatore-44.

Name :

Age :

Sex :

Occupation :

Address for communication :

Declaration:

I have fully understood the nature and purpose of the study. I accept to be a subject in this study. I declare that the above information is true to my knowledge.

Signature of the Subject

Date :

Place :

APPENDIX-1

40 Yard Dash

Sprint or speed tests can be performed over varying distances, depending on the factors being tested and the relevance to the sport. The 40 Yard (36.6 meters) Dash is part of the SPARQ rating system for football, and their protocol is listed here.

Purpose: The aim of this test is to determine acceleration, and also a reliable indicator of speed, agility and quickness.

Equipment required: measuring tape or marked track, stopwatch or timing gates, cone markers, flat and unobstructed grass, track, or turf surface of at least 60 yards.

Procedure: The test involves running a single maximum sprint over 40 yards, with the time recorded. A thorough warm up should be given, including some practice starts and accelerations. Start from a comfortable stationary 3-point stance position, a position that is most familiar to you and that you think will yield the best time. The front foot must be on or behind the starting line. This starting position should be held for 3 seconds prior to starting, you may lean across the starting line, and no rocking movements are allowed. The tester should provide hints to maximizing speed and encouragement to continue running hard past the finish line.

40 yard Sprint Scores

(general guidelines)

College Footballers

4.6 - 4.9 secs

High School Footballers

4.9 - 5.6 secs

Recreational College athletes (male)

~5.0 secs

Recreational College athletes (female)

~5.8 secs

Results: Two trials are allowed, and the best time is recorded to the nearest 2 decimal places. The timing starts from the first movement (if using a stopwatch) or when the timing system is triggered, and finishes when the chest crosses the finish line and/or the finishing timing gate is triggered.

Target population: football and other sports in which speed over that distance is important

Reliability: Reliability is greatly improved if timing gates are used. Also weather conditions and running surface can affect the results, and these conditions should be recorded with the results. If possible, set up the track with a crosswind to minimize the effect of wind.

Comments: 40 yards is 36.58 meters.