Common Muscle Strains LE: HCW

when should physical exam of muscle strain be done

12 hours to 2 days after injury

muscle strain etiology

A muscle strain may occur following cumulative microscopic muscle-damaging events, a single overloading event, or a combination of both.1,2 It is unknown whether a muscle strain requires both high levels of eccentric force and high levels of muscle strain, or if high levels of either can result in this damage.1 Muscle strains most often occur in athletes whose sports require rapid running or changes in direction.1,2

le muscle strain progression

In order to progress from the early to the intermediate phase, a patient with a hamstring strain should be able to perform pain-free walking, slow jogging, and high-knee marching, as well as pain-free isometric contractions against 50-70% of maximum resistance in the standard manual muscle test position (prone with 90 degrees of knee flexion). To progress to the late phase, they should be able to isometrically contract the hamstrings with full strength without pain (positioned in prone with 30 degrees of knee flexion); they also should be able to jog both backwards and forwards at 50% speed without pain.1 Note: There is not a specific consensus on what is required for return to play following a lower extremity muscle strain.1,2,4 However, Erickson and Sherry4 created an algorithm for return to sport following hamstring strains to assist clinicians in this decision-making process. This algorism addresses tenderness to palpation, muscle strength, athlete insecurity, single leg bridging (focus on core strength and eccentric control), sport-specific testing, and athlete pain or hesitation.1,4 Figure 1, a depiction of this algorithm, is included at the end of this worksheet.4

what factors following initial muscle strain have been associated with longer recovery times for those with HS strains

Initial VAS pain rating greater than 6/101,4 • Pain every day for more than 3 days1,4 • Increased time before first consultation1 • Need for more than 1 day to walk pain-free following injury1 • Athlete self-predicts longer time to return to play1 • Ecchymosis4 • Popping sound during injury4 • Greater than 15-degree difference in passive straightening of injured limb compared to uninjured limb4

location of symptoms muscle strain

Symptoms will usually be localized to the site of the affected muscle(s); for instance, with a hamstring strain, a patient will complain of sharp pain, tenderness and potentially tightness in the posterior thigh.1

muscle strain prognosis

Typically, prognosis is excellent following a muscle strain, and there are rarely complications.2 Reinjury is more common if an athlete is older, fatigued, inflexible, has a strength imbalance between the affected and unaffected extremities, or returns to sport within two weeks of the initial injury.1,4 The highest risk for re-injury is typically within the first two weeks returning to sport.4 Injury may be better avoided in the future if patients perform an adequate dynamic warm-up prior to intense exercise or sport, and do not participate in vigorous activities if they are extremely fatigued.2,4

more complex muscle strain will lead to

macroscopic damage; will cause: Damage to the muscle fascia and extracellular matrix • Inflammation • Blood vessel damage • Local ischemia • Collagen and proteoglycan degradation • Release of muscle enzymes

less complex muscle strain will cause:

microscopic damage: lead to Myofibril damage • Leakage of creatine kinase

what muscle strains are the most common

muscles that cross two joints

findings with palpation muscle strain LE

palpate from origin to insertion; reports of tenderness upon palpation/palpable defect

test/measures performed with muscle strain

palpation visual inspection ROM MMT gait analysis

what gait compensation is common with LE muscle strain and why

stiff legged gait because they will have pain with eccentric contraction of m

what can be used to differentiate between a full muscle tear and a partial tear

ultrasound

duration of treatment muscle strain

Generally, muscle strains will heal more quickly than tendon or ligament injuries since muscles have a more extensive blood supply. The specific duration of muscle strain rehabilitation is directly correlated to the location and extent of injury.1,2 A minor strain may heal in as short as one week, while a more severe injury could require 4-8 weeks of rehabilitation before returning to baseline.2 For instance, following a hamstring injury, patients may progress to the intermediate phase of rehabilitation about 2-6 weeks following injury.1 The late rehabilitation phase typically begins around 4-8 weeks following injury.1 If a patient is not consistently progressing towards return to sport after 12-14 weeks, adjunctive therapies such as dry needling and corticosteroid injections may be indicated.1

MRI grading of muscle strains

Grade I: No identifiable disruption of the muscle fibers • Grade II: Partial-thickness tear is defined as grade II, depicted as a hyperintense signal on a T2 weighted image, with a focal hematoma present at the myotendinous junction • Grade III: Complete tear is considered a grade III strain; may or may not include muscle retraction

muscle strain grades

Grade I: results in no loss of strength or function • Grade II: muscle with reduced strength with some residual function • Grade III strain is defined by a complete loss of function of that muscle.

modalities for muscle strains

Dry needling or other adjunctive therapies (e.g. corticosteroid injections, autologous platelet-rich plasma injections) may be indicated for patients who are not consistently progressing after 12-14 weeks of PT rehabilitation.1

activity restrictions muscle strain

Activity restrictions will be dependent on the severity of the muscle strain, as well as the muscle(s) affected; severity can range from minimal loss of function to complete loss of function, depending on the grade of the strain.1 A strain will likely affect an athlete's ability to participate in sport.1,4

aggravating factors muscle strain

Aggravating factors include active or passive stretching of the affected muscle(s).1,2 Pain will likely be most obvious to the patient throughout the phases of gait that involve eccentric activation of the affected muscle, and therefore the patient's sports participation and ADLs will be affected secondary to pain.1,2,4 The patient is also likely to report tenderness upon palpation.1,2

24 hour behavior muscle strains

Aside from changes in pain, inflammation, and ecchymosis within the first 12-48 hours following injury, there is not a significant difference in symptom presentation over the course of 24 hours.1,2 Any changes in symptom presentation will be activity dependent.

LE muscle strain Prevalence

Lower extremity muscle strains are fairly common injuries, especially in athletes; for instance, hamstring strains are the most common lower limb injury in athletes.1 Usually, muscles involved in strains are those that cross multiple joints, contain a high percentage of type II muscle fibers, and/or primarily work eccentrically.2,3 In particular, the most common muscles groups strained are the hamstrings, adductors, quadriceps and gastrocnemius/ soleus.2,3 The vast majority of muscle strains occur in non-contact scenarios (usually from running/ sprinting), and the reinjury rate is high; reinjury occurs in approximately one-third of hamstring strains.3,4

muscle strain pathophys

Muscle strains most often occur during forced stretching of the affected muscle, typically when the muscle is eccentrically contracting.2,4 For instance, hamstring muscle strains often occur during maximal speed running due to the high eccentric demands on the muscle group, specifically during the early stance and swing phases.1,2 The pathophysiology of a muscle strain will depend on the extent of the injury.

working differential muscle strain

Neural pathology resulting in referred pain to the affected muscle(s) may result in a somewhat similar presentation to a lower-extremity muscle strain; to rule out neural pathology, a lumbosacral MRI may be indicated.1,4 Other musculoskeletal conditions of the hip, pelvis, thigh, knee or lower leg (e.g. sacroiliitis, stress fractures, iliotibial band syndrome, knee collateral ligament sprain, gastrocnemius strain), as well as nerve conditions such as piriformis syndrome or sciatica, may also present similarly to a hamstring muscle strain.1,4 Plain-film radiographs may be necessary to rule out avulsion fractures.1

muscle strain risk factors

Non-modifiable risk factors: o Older age,1,4,5 o Previous injuries4,5 • Modifiable risk factors: o Improper warmup1,5 o Weakness in affected muscle and/or strength imbalance between agonist and antagonist muscles1,4 o Fatigue1,4 o Reduced flexibility in affected or adjacent musculature1,4 o Lack of core and pelvic strength and coordination4

non operative treatment options muscle strain

Nonoperative, therapy-based treatment is nearly universal for the management of muscle strains.1,2 An effective rehabilitation program should address all modifiable risk factors (muscle weakness, reduced flexibility, and strength imbalances; core and pelvic strength and coordination; and patient education on proper warm-up and risk of fatigue).1,4,5 Implementation of eccentric training and neuromuscular facilitation is key for successful muscle strain rehabilitation; eccentric resistance training decreases recovery time as well as the risk for recurrent injury in the future.1,4 A patient's apprehension and insecurity should also be addressed throughout rehabilitation.4

alleviating factors muscle strain

One of the most important ways to alleviate pain following a hamstring strain is to limit the aggravating activities. In the acute stage, PRICE (Protection, Rest, Ice, Compression, and Elevation) is recommended to help decrease inflammation and pain.1,2 Medications such as NSAIDs and acetaminophen may also be used to assist with pain relief as necessary.1,2

hx of episode muscle strain

PTs should inquire about... • The activities that preceded the injury1,2 o Hamstring muscle strains often occur following kicking, jumping, high-speed running, or sudden changes in direction, as these activities all eccentrically the hamstrings1,2 • Loss of function in the affected limb1 • Gait impairments1,4 o Patients with hamstring strain often present with a stiff-legged gait because they are attempting to avoid knee extension and hip flexion1 o A strain affecting another muscle of the lower extremity will likely affect the phases of gait during which that muscle is eccentrically contracting • Whether any sounds were heard at the time of injury, such as a pop1 • Previous injuries at or around the affected muscle, and what treatments were implemented following that injury1

muscle strain nature of symptoms

Patients will typically present with acute onset of sharp pain and tenderness at the site of the affected muscle(s), especially during sports activities.1,2 Swelling and ecchymosis may also be present, as well as weakness and progressive tightening of the affected muscle(s).1,2 Muscle defects may be palpated with more severe (i.e. higher grade) muscle strains.1

findings with ROM and MMT muscle strain

ROM performed 48 hours after injury; muscles will be weak and will commonly experience loss of function and complain of pain against resistance

Late Pt management muscle strain

The interventions within this phase are specifically centered around return to sport and mitigating the risk of future re-injury. Manual therapy can be continued throughout this phase, and more aggressive manual therapy may be indicated if there are concerns of excessive scar tissue.1,4 Direct stretching of the affected muscle(s) may also begin in this phase and is very valuable for return to sport; for hamstring strains, stretching four times daily may significantly decrease recovery time compared to once-daily stretching.1 Core strengthening and agility drills should continue to be progressed, and eccentric strengthening of the affected muscle(s) should specifically be implemented at end-range; this increases the stability and strength of the muscle when it is outside of its optimal length-tension relationship, decreasing the risk for future injury.1,4 The patient may also begin plyometrics, running, and returning to sport-specific activities throughout the late phase.1 Return to run and return to sport plans should be implemented gradually to minimize the risk of re-injury.1,4 It is also recommended that an athlete performs a sufficient dynamic warm-up prior to activity to reduce the risk of re-injury.1,2,4

typical impairments muscle strain

The most common impairments seen with muscle strains are decreased strength and range of motion.1-4 The patient will likely be limited by pain as well, especially in the early and intermediate stages of rehabilitation.1

intermediate Pt management

When normal, pain-free ambulation is reached, the physical therapist should continue to progress the agility and core stabilization exercises that were first implemented in the early stage.1 Additionally, the physical therapist can begin to implement moderate resistance training and eccentric strengthening of the affected muscles.1,4 Manual therapy that indirectly addresses joint mobility or flexibility limitations may also be indicated at this time, but direct stretching of the affected muscle(s) should still be avoided.1 PRICE can still be continued throughout this phase, and all activities should be modified as necessary so that they are pain-free.1

early PT management

With an acute muscle strain, activity should be limited, and PRICE should be implemented.1,2 If both of these strategies are not effective in reducing pain, acetaminophen or NSAIDs may be used as well to assist with pain control.1,2 If gait is antalgic, an AD should be used. Direct stretching of the affected muscle(s) should be avoided at this time.1 Low-intensity, pain-free activities, such as stationary biking, agility exercises, and core stabilization exercises, may indicated during early rehabilitation.1,4