Hamstring Strain

Description

A hamstring strain is caused by a rapid broad contraction or intense stretching of the hamstring muscle group, which results in high mechanical stress. This results in varying degrees of rupture within the fibers of the tendon unit. [1]

Hamstring strains are common in sports of a dynamic nature, such as sprint jumping contact sports, such as Australian Rules Football (AFL) American football and soccer, where rapid eccentric contractions are regular. In football, this is the most common injury. [1]. Hamstring injuries can also occur in Recreational sports, such as water skiing and bull riding, force the knee into full extension during the injury.

The hamstrings are made up of three muscles:

• The biceps femoris
• The semitendinosus and
• The semimembranosus. [2]

For a more detailed look at the anatomy of the hamstrings, see the article on the hamstrings.

[3]

Epidemiology/Etiology

The cause of a hamstring muscle strain is often unknown. During the second half of the swing phase, the hamstrings are at their maximum length, when they develop maximum tension [4]. During this phase, the hamstrings contract eccentrically to slow flexion of the hip joint and extension of the lower body legs [5]. At this point, the muscle spindle activity of the hamstrings is at its peak. Requires a strong contraction of the hamstrings and relaxation of the quadriceps. According to “Klafs and Arnheim”, the breakdown of coordination between these opposing muscles may be Resulting in a hamstring tear [5]. The greatest muscle-tendon stretch is caused by the biceps femoris, which may cause it to be more prone to injury than the other 2 hamstrings (semimembranosus and semitendinosus) during high-speed running. [6]

Predisposing Factors/Risk Factors

There are various risk factors that may play a role in hamstring injuries:[7][8]

• Older age
• Previous hamstring injury
• Limited hamstring flexibility[9]
• Increased fatigue
• Poor core stability
• Strength imbalance
• Ethnicity
• Previous calf injury
• Previous substantial knee injury
• Osteitis pubis
• Increased quadriceps flexibility was inversely associated with incidence of hamstring strains in a cohort of amateur Australian Rules football players
• Players presenting certain polymorphisms of IGF2 and CCL2 (particularly their allelic form GG) may be more susceptible to serious injury and should participate in specific prevention programs
• Tight hip flexors[10]
• Previously associated lumbar abnormalities. Kicking and abdominal strengthening exercises with straight legs have been identified as possible causes of lordosis. Anatomical reasons appear to be that the iliopsoas group is primarily involved in kicking and Straight-leg raises or straight-leg sit-ups help strengthen this muscle’. Therefore, certain physical activities and training methods that exacerbate postural deficits may also predispose athletes to injury. [11]

During activities such as running and kicking, the hamstrings lengthen with hip flexion and knee extension, and this lengthening can reach the muscle’s mechanical limit or lead to the accumulation of microscopic muscle damage. [12] Possible hamstring injury Potential uncoordinated contraction of the biceps femoris muscle secondary to dual nerve supply. [7]

Another debate concerns changes in the hamstrings in the muscular structure. The short head of the biceps femoris (BFS) has a longer bundle (allowing greater muscle extensibility and reducing the risk of over-stretching during eccentric contractions) and a longer bundle than Long head of biceps femoris (BFL). While BFL presents shorter fascicles compared with BFS, BFS undergoes repetitive over-lengthening and cumulative muscle damage.

Excessive forward pelvic tilt lengthens the hamstrings, which some research suggests may increase the risk of strain injuries. [13]

Characteristics/Clinical Presentation

A hamstring strain can cause sudden onset of mild to severe pain in the back of the thigh. The impression of bursting or tearing can also be described. [14] Swelling and bruising may sometimes occur, but they may be delayed for several days after the injury. Rarely symptoms are numbness, tingling and Distal extremity weakness. These symptoms warrant further investigation for sciatic nerve irritation. Large hematomas or scar tissue can result from complete tears and avulsions.

Other possible symptoms:[6]

• Pain
• Tenderness
• Loss of motion
• Decreased isometric strength
• Decreased length of the hamstrings

Hamstring strains are divided into 3 groups based on the degree of painful weakness and loss of motion.

• Grade 1 (mild): Only a few muscle fibers are damaged or broken. This rarely affects muscle strength and endurance. Pain and sensitivity usually occur the day after the injury (varies from person to person). Normal patient complains of posterior stiffness leg. The patient can walk normally. There may be slight swelling, but the knee can still bend normally. [15] [16]
• Grade 2 (moderate): About half of the fibers are torn. Symptoms are acute painful swelling and mild loss of function. The patient’s walking will be affected. Pain can be reproduced by exerting precision on the hamstring muscles or bending the knee against resistance. [15] [16]
• Grade 3 (severe): From more than half of the fibers ruptured to complete muscle rupture. Both the muscle belly and the tendon suffer from this injury. It causes great swelling and pain. The function of the hamstring cannot be exerted, and the muscles show Great weakness. [15] [16]

Differential Diagnosis

When examining a patient, a physical therapist may have to differentiate between different injuries such as

• Adductor strain and avulsion injury Lumbosacral referred pain syndrome Piriformis syndrome Sacroiliac dysfunction Sciatica Hamstring tendonitis and sciatic bursitis [14]
• Other sources of hamstring pain may also be confused with a hamstring strain and should be considered during the examination. Specific tests and imaging are used to assess and rule out the possibility of those different pain sources. [14]
• Restricted sciatic nerve mobility can lead to pain in the back of the thigh, and in some cases, adverse nerve tension may be the sole source of pain without any specific muscle damage. In some cases, it can be difficult to determine whether it is the hamstrings or another muscle group such as the glutes Injured adductor muscles due to proximity (eg M. Gracilis and M. Adductor Magnus and Longus.). Imaging procedures may sometimes be needed to determine the exact location of the injury. [14]
• Other conditions with a similar presentation to hamstring strains include popliteus strain tendonitis at either origin of the gastrocnemius muscle, posterior cruciate ligament apophysitis-ischial tuberosity pain, lumbar spine disease, and superior tibiofibular joint injury. [14]

Diagnostic Procedures

Most acute injuries can be easily detected by having the patient tell how the injury occurred. To be sure, they’ll have to do some research on the hamstring, too.

When the therapist is not sure, he can order medical imaging. This would rule out all other possibilities. [12]

• X-rays: One of the benefits of X-rays is that through this imaging, the cause of the pain can be distinguished. It can differentiate between muscular disorders, such as muscle strains, or bone disorders, such as stress fractures. [15]
• Ultrasound (US): This imaging method is heavily used because it is an inexpensive method. It’s also a great approach because it enables dynamic imaging of muscles. The disadvantage of ultrasound is that it requires a skilled and experienced clinician. [15] [17]
• Magnetic resonance imaging (MRI): MRI provides a detailed view of muscle damage. But sometimes it may not be clear according to the image. If this occurs, the therapist must rely on the story the patient tells him (see Characteristics/Clinical Presentations). [15] [17]

MRI studies are performed to distinguish two main groups of muscle damage: direct or indirect.

• In the group of injuries caused by indirect trauma, the classification introduces the concepts of functional and structural damage. Changes in functional muscle damage occur but there is no macroscopic evidence of fiber tearing. These lesions have a variety of causes and are divided into the following subgroups Reflecting its clinical origin, such as overload or neuromuscular disease. Structural muscle injuries are those where MRI studies show macroscopic evidence of fibrous tearing, i.e. structural damage. They are usually located at the tendon junction because these areas are biomechanically weak point. [18] Some studies have screened patients after hamstring injuries and they have concluded that normalization of this increased signal intensity in MRI does not appear to be necessary for a successful return to play (RTP) [19] 。

Injury type definition MRI Direct contusion: blunt trauma from external agent, intact tear of muscle tissue: blunt trauma from external agent with muscle rupture hematoma Indirect: functional 1A: muscle impairment due to fatigue acute muscle soreness Inflammatory Pain Type 2: Muscle disorders of neuromuscular origin 2A: Spine-related neuromuscular disorders Increased muscle tone due to neurological disorders 2B: Muscle-related neuromuscular disorders Increased muscle tone due to altered neuromuscular control Negative Negative or isolated of Edema structure Type 3: partial muscle tear 3A: mild partial muscle tear: tear involving a small area of maximum muscle diameter 3B: moderate partial muscle tear: tear involving a moderate area of maximum muscle diameter Type 4: ( Sub) total muscle tear with avulsion: involves the entire muscle Diameter muscle defect with disrupted contraction of fibers and complete interruption of hematoma fibers

Outcome Measures

• FASH: The FASH (Functional Assessment Scale for Acute Hamstring Injury) questionnaire is a self-administered questionnaire that is now only available in Greek, English and German. Because hamstring injuries are the most common soccer injuries, they tested for validity and reliability German-speaking football players with acute hamstring injuries on the FASH-G (G = ⟩ German version) questionnaire. The FASH-G is a valid and reliable tool for assessing and determining the severity of hamstring injuries in a population of athletes. [20]
• LEFS: lower extremity function scale
• SFMA: The Selective Functional Movement Assessment (SFMA) is a clinical assessment system designed to identify musculoskeletal dysfunction by assessing limitations of basic movement or provocation of symptoms. [twenty one]
• PSFS: Patient Specific Functioning Scale
• VAS: Visual Analog Scale
• NPRS: Numerical Pain Rating Scale  

Examination

Running Gait: The physical examination begins with an examination of running gait. People with hamstring strains often have a shortened walking gait. Swelling and bruising are not always detectable in the initial stages of an injury as they usually appear a few days after the injury initial injury.

Observations: Physical examination also presents visible findings. Examine the posterior thigh for asymmetric swelling ecchymosis and deformity.

Palpation: Palpation of the posterior thigh can be used to identify specific areas of injury due to pain provocation, as well as to determine the presence of palpable defects in the musculotendinous unit. With the patient lying prone, repeat knee flexion and extension without Resistance through small ranges of motion may help identify the location of individual hamstring muscles and tendons. With the knee held in full extension, the point of greatest pain can be identified by palpation and positioned relative to the ischial tuberosity Measure the total length of the painful area. Total length width and the distance between the ischial tuberosity and the area of greatest pain were measured in centimeters. [22] Although these two measurements are only used for the location of the point of greatest pain (relative to the ischium nodules) are associated with the recovery period. That is, the closer you are to the site of greatest pain, the longer it will take to return to your pre-injury level. Proximity to the ischial tuberosity is thought to reflect the extent of tendon involvement proximal to the injured muscle So the recovery period is longer. [6]

Range of motion: Range of motion testing should consider both the hip and knee. Passive straight leg raises (hips) and active knee extension tests (knees) are often used sequentially to estimate hamstring flexibility and maximal length. Typical hamstring length should allow hip flexion 80° in the passive straight leg raise and up to 20° of knee extension in the active knee extension test. When assessing muscle length after injury, available range of motion should be based on patient-reported episodes of discomfort or stiffness. in serious injury In athletes these tests are often limited by pain and therefore may not accurately assess muscular tendon extensibility. Again, a two-sided comparison is recommended.

Hip Flexibility The hip flexion test combines a passive unilateral straight leg raise (SLR) test with pain assessment according to the Borg CR-10 scale. The sprinter lies supine with the pelvis and opposite leg strapped in place. A standard flexometer is placed 10 cm into the skull The bottom of the patella. With plantar flexion, the investigator slowly (approximately 30 degrees) raises the leg, with the knee straight, until the subject estimates a 3 (“moderate pain”) on the Borg CR-10 scale (0 = no pain, 10 = maximum pain) ). The hip flexion angle at this time Record and take the maximum angle of 3 repetitions as the Range of Motion (ROM) test result. Values for the injured leg are expressed as a percentage of the uninjured leg for intra-group and inter-group comparisons. There was no warm-up prior to flexibility measurements.

Knee flexion strength: Isometric knee flexion strength was measured in sprinters in the prone position with the pelvis and contralateral leg immobilized. The ergometer is placed perpendicular to the calf at the ankle. The foot is in plantar flexion and the knee is in extension. three Maximal voluntary isometric knee flexion contraction with each gradual increase in force. Each contraction lasts 3 seconds, with a 30-second rest in between. Take the highest force value as the strength test result [23]. Attempt to bias the inner or outer hamstrings internally Or separately externally rotating the calf during strength testing may help identify the muscles involved.

Clinical tests:

A systematic review by Reiman et al examined clinical trials for hamstring injuries. [24] This review included patients presenting with hamstring or posterior thigh pain, but excluded those whose pathology was associated with conditions originating elsewhere that transferred the pain to The hamstring/posterior thigh (i.e. lumbar spine) results are as follows [24]:

• Puranen-Orava Test – Actively stretch the hamstrings in a standing position with hips flexed approximately 90*, knees fully extended, and feet on a firm surface. Positive – symptoms worsen. (SN 0.76 SP 0.82 +LR 4.2 -LR 0.29)
• Knee stretch test (SN 0.84 SP 0.87 +LR 6.5 -LR 0.18)
• Modified flexed knee tension test (SN 0.89 SP 0.91 +LR 9.9 -LR 0.12)
• Shoe Off Test / Hamstring Resistance Test (SN 1.00 SP 1.00 +LR 280.0 -LR 0.00)
• Active ROM test (SN 0.55 SP 1.00 +LR 154.6 -LR 0.50)
• Passive ROM test (SN 0.57 SP 1.00 +LR 160.6 -LR 0.43)
• Resistance ROM test (SN 0.61 SP 1.00 +LR 170.6 -LR 0.40)

Tests Summary TestSensitivitySpecificity+LR-LRPuranen-Orava0.76 0.824.20.29Bent-Knee stretch 0.840.876.50.18Modified Bent-knee stretch0.890.919.90.12Taking off the shoe1.001.002800.00Active ROM 0.551.00154.60.50Passive ROM 0.571.00160.60. 43電阻ROM 0.611.00170.60.40

LR: The likelihood ratio allows the best use of clinical test results to make a diagnosis for an individual patient.

+LR: Individuals with the target disease have a higher probability of testing positive than individuals without the target disease

-LR: the probability that a person with the condition tests negative/probability than an individual without the condition has negative test

Medical Management

Surgical intervention is extremely rare following a hamstring strain. Surgery is only recommended if the hamstring is completely torn. Almost all patients felt that they had improved with surgery. A study [25] showed that 91% of people were satisfied with their Happiness is 75% or higher. Hamstring endurance tests and hamstring strength tests were better and scored higher after surgery. Muscle strength tests after surgery ranged from 45% to 88%. Hamstring endurance tests range from 26% to 100%. physical examination and Follow-up showed that all repairs were intact.

Physiotherapy Management

The primary goal of a physical therapy and rehabilitation program is to maximize the return of patient function and/or return the athlete to a previous level of activity while minimizing the risk of re-injury.

Hamstring strains remain a challenge for athletes and clinicians given their high incidence, slow healing, and persistent symptoms. Furthermore, nearly one-third of these injuries recur within the first year of returning to sport, with subsequent injuries often more severe than the original. [26] Using a specific and adequate training program for recovery from hamstring strains may be a decisive factor in healing and preventing recurrent hamstring strains. Different kinds of therapy are used to recover from a hamstring strain, but are they all like Is it effective enough in the first year after returning to sport to prevent recurrence? Different studies have attempted to show the effect of eccentric exercises such as dry needling and deep peeling massage on hamstring strain rehabilitation.

The use of eccentric strengthening during long muscle length exercises as a rehabilitation tool to examine the effect of preventing recurrence of hamstring injuries after revalidation. The results showed that using eccentric strength training on the long muscles had a positive effect. effect[27]

On the other hand, one study attempted to compare eccentric strength training (STST) with progressive agility and trunk stabilization training (PATS). Rehabilitation in the STST group consisted of static stretching isolated progressive hamstring resistance training and ice packs. PATS Group Includes progressive agility and trunk stability exercises and ice therapy. The study found that patients who rehabilitated through progressive agility and trunk stabilization had significantly better outcomes. Significantly lower rates of reinjury in the PATS group after one year Return to sport (1 of 13 athletes instead of 7 of 11 athletes in the STST group). Rehabilitation programs consisting of progressive agility and trunk stability exercises are more effective than programs emphasizing isolated hamstring stretching and strengthening Return to sport and prevent re-injury in athletes with acute hamstring strains. [28]

Deep peeling massage is another technique used in hamstring strain rehabilitation. Most of the time it is combined with other rehabilitation techniques. Use Deep Stripping Massage (DSMS) alone or in combination with eccentric resistance to examine the effect on hamstring length and strength. These results show that DSMS increased hamstring length but had no effect on strength in less than 3 minutes. Additionally, combining DSMS with eccentric resistance produces more hamstring flexibility than DSMS alone, without compromising strength. [29]

Functional dry needling combined with an eccentric training program has been reported to be effective in relieving pain and dysfunction following muscle strain, but there is limited published literature on its effects on recovery or injury recurrence. [30]

The Effects of Kinesiology Taping has been shown to be effective in increasing muscle flexibility, which can prevent or reduce the risk of injury. [31] Kinesiology tape can be used in conjunction with other rehabilitation programs to improve muscle flexibility.

There are many techniques and procedures that can be used to revalidate a hamstring strain, but the effectiveness of these techniques cannot all be proven due to a lack of research. Therefore, eccentric training is the most widely known and most used program Rehabilitation of a hamstring strain. The use of this approach has shown good results. A common criticism of rehabilitation programs that emphasize eccentric strength training is the lack of focus on the musculature surrounding the hamstring. someone suggested Neuromuscular control of the lumbopelvic region is required for optimal hamstring function during normal physical activity.

Example Rehabilitation Protocol

Phase I (week 0-3)

Goals

• Protect healing tissue
• Minimize atrophy and strength loss
• Prevent motion loss

Precautions

• Avoid excessive active or passive lengthening of the hamstrings
• Avoid antalgic gait pattern

Rehab

• Ice – 2-3 times daily
• Stationary bike
• Sub-maximal isometric at 90, 60 and 30
• Single leg balance
• Balance board
• Soft tissue mobs/IASTM
• Pulsed ultrasound (50% duty cycle 1 MHz 1.2 W/cm2)
• Progressive hip strengthening
• Painfree isotonic knee flexion
• Active sciatic nerve flossing
• Conventional TENS

Criteria for moving to the next stage

• Normal walking stride without pain
• Painless isometric contraction against submaximal (50%-75%) resistance in prone position with knee flexed to 90 degrees.

Phase 2 (week 3-12)

Goals

• Restore Pain-Free Hamstring Strength with Full ROM
• Develop neuromuscular control of the trunk and pelvis with gradual increases in movement and speed in preparation for functional movement

Precautions

• If painful, avoid end-range extensions in the hamstring

Rehab

• Ice – post-exercise
• Stationary bike
• Running on a treadmill at a pain-free pace and stride of moderate to high intensity
• Constant Velocity Eccentric in Non-Extended State
• Single Limb Balance Windmill Weightless Touch
• Single leg stance with perturbations
• Supine hamstring curls on theraball
• STM/IASTM
• Nordic hamstring Ex
• Shuttle jumps
• Prone leg drops
• Lateral and retro band walks
• Sciatic nerve tensioning

Eccentric protocol

• Once you’re comfortable with non-weightbearing exercises, you can start low-speed eccentric movements such as straight-leg deadlifts, eccentric hamstring pushdowns/Nordic hamstring Ex*, and split squats.

*Nordic Hamstring Ex

Criteria for progression

• Prone knee flexed 90 degrees at full strength 5/5 Painless
• Jogging at a moderate intensity before and after pain-free
• Strength deficit of less than 20% compared to the uninjured limb
• Painless maximum eccentricity in non-stretched state

Phase 3 (week 12+)

Goals

• Symptom-free during all activities
• Normal concentric and eccentric forces through full ROM and speed
• Improve neuromuscular control of the trunk and pelvis
• Integrate Postural Control into Specific Movements

Precautions

• Train within symptoms free intensity

Rehab

• Ice – Post Exercise – As Needed
• Tolerable moderate-to-high-intensity treadmill
• Terminal ROM Isokinetic Eccentric Training (Hyperflexion)
• STM/IASTM
• Plyometric jump training
• 5-10 yard accelerations/decelerations
• A single-limb balance pinwheel touches a heavy object on an unstable surface
• Sport-specific training combining postural control and progressive speed

Eccentric protocol

• Include higher velocity eccentric exercises, including plyometrics and sport-specific activities
• Examples: Includes squat jumps, split jumps, jumping and deep jumps, single-leg jumps, backward jumps, jumps, side jumps, side jumps, zigzag jumps, boundary-enhanced box jumps, eccentric backward steps, eccentric lunge drops, Eccentric Forward Pulls, Single and Double Leg Deadlifts, and Split Stances Deadlift (Good morning Ex)

Return to sport criteria

• Pain-free at full strength in the extended state test position
• Peak torque knee flexion angle bilateral symmetry
• Full ROM without pain
• To replicate the actions of a specific sport at race speed without symptoms.
• Isokinetic strength tests shall be carried out under concentric and eccentric action conditions. The ratio of eccentric hamstring strength (30d/s) to concentric quadriceps strength (240d/s) should be less than 5% [32].