Who “kneeds” quadriceps strain sidelining them?! Bad puns may be annoying, but so can a nagging quadriceps injury. Whether you hit the hardwood, the gridiron or the baseball diamond, a quadriceps strain can hit you.
The quadriceps muscle is actually a group of four muscles in your front thigh that connect to your knee just below the knee cap. They straighten the knee to help you kick a ball. They bend your knee, enabling you to squat. They move your leg forward as you run and fire as your foot contacts the ground to absorb shock. These muscles also help you jump and provide stability during one-leg standing like during a layup. (Blame them for your inability to dunk!)
When Knees Are A Pain
Athletes with quadriceps strains often complain of a “pulling” sensation in the front of the thigh. Pain, swelling, bruising and muscle tenderness may also occur. Its severity is categorized by grades:
- Grade 1 is where the player has mild discomfort in the thigh and no loss of strength.
- Grade 2 is when moderate pain, swelling and some loss of strength occurs.
- Grade 3 is a complete rupture of the fibers leaving the player in severe pain and unable to walk. Grade 3 usually requires surgery.
Quadriceps tears can sideline a player anywhere from two weeks to three months depending on the severity.
Why You’re Sidelined
If a sudden motion overpowers the strength of the quads’ muscle fibers, tears can occur. This injury is common in football, basketball, soccer, running and baseball.
Sudden twists can also cause a tear in the quads, but other factors like muscle fatigue, tightness and muscle imbalance can predispose your to quadriceps tears.
A torn quad can really mess with your performance. Think of sitting into a low chair — the quadriceps help control lowering you into the seat by working in unison with the hamstrings. If the quadriceps are not strong enough to counter the hamstring force, you “plop” down. This “ plopping” is not what you want coming down after rebounding a basketball!
In football, a lineman’s quads contract to straighten the knee, thrusting him to an upright position from a squatting position into an opposing player who weighs 300 pounds. If a tear is present, the player will have less power to boost him into the hit.
How To Get Back In The Game
Keeping muscle fibers in good alignment allows them to glide well and tolerate forces. Stretching and strengthening can help do this.
Prone Stretch On A Bench (Don’t allow back to arch)
- Lie on stomach, keeping pelvis flat on a table or bench
- Place one leg on table and the other on the floor
- Bring heel of table leg towards buttocks
- Hold 30 seconds
- Step up slowly onto a six-inch step and straighten knee
- Keep knees in line with big toe and second toe
- Now slowly lower foot back down in a controlled knee bend
- Don’t let hip pop out to side
- 2 sets of 10 reps
Ball vs. Wall
- Lean against a physioball that is between your back and wall
- Slowly squat down keeping knees in line with big toe and second toe
- 2 sets of 10 reps
Always check with a physician prior to any exercise routine. And remember: You may be sidelined. but not for long!
WebMD defines a quad strain and helps you get back in the game.
Quadriceps Muscle Strain
- 1 Definition/Description
- 2 Clinically Relevant Anatomy
- 3 Epidemiology/ Etiology
- 4 Mechanism of injury
- 5 Characteristics/Clinical Presentation
- 5.1 Grades of quadriceps strain
- 5.2 Observation and palpation
- 6 Differential Diagnosis
- 7 Diagnostic Procedures
- 7.1 Medical Imaging
- 7.2 Outcome Measures
- 7.3 Examination
- 8 Medical Management
- 8.1 Surgery
- 8.2 Indications for Surgery
- 8.3 Recommended Principles for Surgery
- 8.3.1 Post operative treatment
- 9 Physical Therapy Management
- 9.1 Knee Positioning
- 9.2 Rice Therapy
- 9.3 Active Phase of Management
- 10 Rehabilitation Protocol Example 
- 10.1 Return to Sports Criteria
- 11 Key Research
- 12 Clinical Bottom Line
- 13 References
A quadriceps muscle strain is an acute tearing injury of the quadriceps.This injury is usually due to an acute stretch of the muscle, often at the same time of a forceful contraction or repetitive functional overloading. The quadriceps, which consists of four parts, can be overloaded by repeated eccentric muscle contractions of the knee extensor mechanism. 
Acute strain injuries of the quadriceps commonly occur in athletic competitions such as soccer, rugby, and football. These sports regularly require sudden forceful eccentric contraction of the quadriceps during regulation of knee ﬂexion and hip extension. Higher forces across the muscle–tendon units with eccentric contraction can lead to strain injury. Excessive passive stretching or activation of a maximally stretched muscle can also cause strains. Of the quadriceps muscles, the rectus femoris is most frequently strained. Several factors predispose this muscle and others to more frequent strain injury. These include muscles crossing two joints, those with a high percentage of Type II ﬁbers, and muscles with complex musculotendinous architecture. Muscle fatigue has also been shown to play a role in acute muscle injury. 
Clinically Relevant Anatomy
The Quadriceps femoris is a hip flexor and a knee extensor. It is located in the anterior compartment of the thigh. This muscle is composed of 4 sub components:
The Rectus femoris is the only part of the muscle participating in both flexion of the hip and extension of the knee. The other 3 parts are only involved in the extension of the knee. The rectus femoris is the most superficial part of the quadriceps and it crosses both the hip and knee joints, thus also making it more susceptible to stretch-induced strain injuries.  The most common sites of strains are the muscle tendon junction just above the knee (both distal and proximal but most frequently at the distal muscle-tendon) and in the muscle itself.
Literature studies does not reveal great consensus when it comes to classifying muscle injuries, despite their clinical importance. However, the most differentiating factor is the trauma mechanism. Muscle injuries can therefore be broadly classified as either traumatic (acute) or overuse (chronic) injuries.
Acute injuries: are usually the result of a single traumatic event and cause a macro-trauma to the muscle. There is an obvious link between the cause and noticeable symptoms.They mostly occur in contact sports such as rugby, soccer and basketball because of their dynamic and high collision nature.  
Overuse:(chronic or exercise-induced injuries)are subtler and usually occur over a longer period of time.They result from repetitive micro-trauma to the muscle. Diagnosing is more challenging since there is a less obvious link between the cause of the injury and the symptoms. 
Mechanism of injury
There are generally three mechanisms of injury for a quadriceps strain:
1. Sudden deceleration of the leg (e.g. kicking),
2. violent contraction of the quadriceps (sprinting) and
3. rapid deceleration of an overstretched muscle (by quickly change of direction).
Grades of quadriceps strain
Strains are graded 1 to 3 depending on how bad the injury is, with a grade 1 being mild and a grade 3 involving a complete or near complete tear of the muscle.
Grade 1 symptoms
Symptoms of a grade 1 quadriceps strain are not always serious enough to stop training at the time of injury. A twinge may be felt in the thigh and a general feeling of tightness.The athlete may feel mild discomfort on walking and running might be difficult.There is unlikely to be swelling. A lump or area of spasm at the site of injury may be felt.
Grade 2 symptoms
The athlete may feel a sudden sharp pain when running, jumping or kicking and be unable to play on.Pain will make walking difficult and swelling or mild bruising may be noticed.The pain would be felt when pressing in on the suspected location of the quad muscle tear.Straightening the knee against resistance is likely to cause pain and the injured athlete will be unable to fully bend the knee.
Grade 3 symptoms
Symptoms consist of a severe,sudden pain in the front of the thigh.The patient will be unable to walk without the aid of crutches.Bad swelling will appear immediately and significant bruising within 24 hours.A static muscle contraction will be painful and is likely to produce a bulge in the muscle.The patient can expect to be out of competition for 6 to 12 weeks. 
Observation and palpation
The therapist will have a close look at the injured area, observing for swelling and bruising in particular.They should also observe the patient in standing and walking, looking for postural abnormalities.Palpation of the quadriceps muscle should occur along the entire length of the muscles and the aponeuroses.This is required to identify swelling, thickening, tenderness, defects and masses if present.
- Jumper’s Knee
- Femoral Neck Stress Fracture
- Slipped Capital Femoral Epiphysis
- Previous injury seems not to constitute a risk factor 
Most acute injuries in the quadriceps muscles can be found easily by the therapist by just letting the patient tell how the injury occurred and doing a quick examination of the quadriceps muscles afterwards. But when the therapist isn’t too sure, he can always consider medical imaging to give a definite answer. Medical imaging tells us for example the exact type and location of the muscle strain. 
After obtaining a thorough history, a careful examination should ensue including observation, palpation, strength testing, and evaluation of motion.
- Observation: Strain injuries of the quadriceps may present with an obvious deformity such as a bulge or defect in the muscle belly. Ecchymosis may not develop until 24 hours after the injury.
- Palpation of the anterior thigh should include the length of the injured muscle, locating the area of maximal tenderness and feeling for any defect in the muscle. Acute compartment syndrome should be considered if there is tenseness of the fascial envelope surrounding the compartment and pain out of proportion to the clinical situation
- Strength testing: of the quadriceps should include resistance of knee extension and hip flexion. Adequate strength testing of the rectus femoris must include resisted knee extension with the hip flexed and extended. Practically, this is best accomplished by evaluating the patient in both a sitting and prone-lying position. The prone-lying position also allows for optimum assessment of quadriceps motion and flexibility. Pain is typically felt by the patient with resisted muscle activation, passive stretching, and direct palpation over the muscle strain.
- Assessing tenderness:any palpable defect and strength at the onset of muscle injury will determine grading of the injury and provide direction for further diagnostic testing and treatment.
There are several types of medical imaging which can be used for muscle strains:
- Radiographs: a positive point about radiographs is that they are good to differentiate the etiology of the pain in the quadriceps muscles. Etiologies can be muscular (muscle strain etc.) or bony (stress fracture etc.).
- Ultrasound: Ultrasound is very often used because it is relatively inexpensive. But it also has a quite big disadvantage, namely the fact that it’s highly operator dependent and requires a skilled and experienced clinician. Another advantage of US is the fact that it has the ability to image the muscles dynamically and to asses for bleedings and hematoma formation via Doppler.
- Magnetic resonance imaging (MRI): MRI is a good way to give detailed images of the muscle injury. If it’s not clear whether it’s a contusion or a strain, the therapist must rely on the patient’s recollection of the injury in order to deduce whether it is a contusion or strain. 
- Voluntary activation by superimposing percutaneous electrical stimulation on to an isometric quadriceps. When the muscle is fully activated, the electrical stimulation does not generate additional force above the voluntary contraction.
- Muscle test: quadriceps force and ROM. There are 5 grades of manual testing: Grade 0 is the lowest grade where the patient isn’t able to do anything . Grade 5 is the highest grade where the patient can move his leg against a maximum resistance given by the therapist. 
Ely’s test :The Ely’s test (or Duncan-Ely test) is used to assess rectus femoris spasticity or tightness.
The patient lies prone in a relaxed state. The therapist is standing next to the patient, at the side of the leg that will be tested. One hand should be on the lower back, the other holding the leg at the heel. Passively flex the knee in a rapid fashion. The heel should touch the buttocks. Test both sides for comparison. The test is positive when the heel cannot touch the buttocks, the hip of the tested side rises up from the table, the patient feels pain or tingling in the back or legs.
Other evaluation methods are:
• Hamstrings/Quadriceps ratio (H vs. Q) – A calculation in which the strength (peak torque) of the hamstring muscles in eccentric motion is divided by the strength of the quadriceps in a concentric motion: Asymmetries/dysbalances in the functional H/Q ratio was shown to significantly impact injury incidence .
• Range of motion decrease (ROM)
• Muscle strength loss
• Skin temperature
• Pain (under pressure)
• Bruises (ecchymosis)
• Sore end-feel
The use of NSAID’s ( nonsteroidal anti-inflammatory drugs) is still controversial, their benefit, cost and potential adverse effects may be taken into consideration. If used, it should be during the inflamatory period (48h-72h) 
Surgical Intervention may be necessary if there is a complete quadriceps muscle rupture.
There has been an experimental study (1998) about the use of hyperbaric oxygen therapy. The therapy should be applied during the early phase of the repair of the injured muscle.This therapy could accelerate the repair of the injured muscle. Care should be taken to extend these findings to clinical practice, as there is not enough scientific evidence on the use of hyperbaric oxygen therapy in the treatment of muscle or other types of soft tissue injuries in athletes.  
One should exercise extreme caution in considering surgical intervention in the treatment of muscle injuries, as a properly executed nonoperative treatment results in a good outcome in virtually all cases. In fact, the phrase “muscle injuries do heal conservatively” could be used as a guiding principle in the treatment of muscle traumas.
Having said that, there are certain highly specific indications in which surgical intervention might actually be beneficial.
Indications for Surgery
- large intramuscular hematoma(s),
- a complete (III degree) strain or
- tear of a muscle with few or no agonist muscles, or
- a partial (II degree) strain if more than half of the muscle belly is torn.
- surgical intervention should be considered if a patient complains of persisting extension pain (duration, >4-6 months) in a previously injured muscle, particularly if the pain is accompanied by a clear extension deficit. In this particular case, one has to suspect the formation of scar adhesions restricting the movement of the muscle at the site of the injury, a phenomenon that often requires surgical debridement of the adhesions.
If surgery is indeed warranted in the treatment of an acute skeletal muscle injury, the following general principles are recommended:
Recommended Principles for Surgery
- The entire hematoma and all necrotic tissue should be carefully removed from the injured area.
- One should not attempt to reattach the ruptured stumps of the muscle to each other via sutures unless the sutures can be placed through a fascia overlying the muscle.Sutures placed solely through myofibers possess virtually no strength and will only pierce through the muscle tissue.
- Loop-type sutures should be placed very loosely through the fascia, as attempts to overtighten them will only cause them to pierce through the myofibers beneath the fascia, resulting in additional damage to the injured muscle. It needs to be emphasized here that sutures might not always provide the required strength to reappose all ruptured muscle fibers, and accordingly, the formation of empty gaps between the ruptured muscle stumps cannot always be completely prevented.
- As a general rule of thumb, the surgical repair of the injured skeletal muscle is usually easier if the injury has taken place close to the MTJ, rather than in the middle of the muscle belly, because the fascia overlying the muscle is stronger at the proximity of the MTJ, enabling more exact anatomical reconstruction.
- In treating muscle injuries with 2 or more overlying compartments, such as the muscle quadriceps femoris, one should attempt to repair the fascias of the different compartments separately, beginning with the deep fascia and then finishing with the repair of the superficial fascia.
- After surgical repair, the operated skeletal muscle should be supported with an elastic bandage wrapped around the extremity to provide some compression (relative immobility, no complete immobilization, eg, in cast, is needed).
- Despite the fact that experimental studies suggest that immobilization in the lengthened position substantially reduces the atrophy of the myofibers and the deposition of connective tissue within the skeletal muscle in comparison to immobilization in the shortened position, the lengthened position has an obvious draw-back of placing the antagonist muscles in the shortened position and, thus, subjecting them to the deleterious effects of immobility.
After a careful consideration of all the above-noted information, we have adopted the following postoperative treatment regimen for operated muscle injuries.
Post operative treatment
- The operated muscle is immobilized in a neutral position with an orthosis that prevents one from loading the injured extremity.
- The duration of immobilization naturally depends on the severity of the trauma, but patients with a complete rupture of the m. quadriceps femoris or gastrocnemius are instructed not to bear any weight for 4 weeks,
- Although one is allowed to cautiously stretch the operated muscle within the limits of pain at 2 weeks postoperatively.
- Four weeks after operation, bearing weight and mobilization of the extremity are gradually initiated until approximately 6 weeks after the surgery, after which there is no need to restrict the weightbearing at all.
Experimental studies have suggested that in the most severe muscle injury cases, operative treatment may provide benefits. If the gap between the ruptured stumps is exceptionally long, the denervated part of the muscle may become permanently denervated and atrophied. Under such circumstances, the chance for the reinnervation of the denervated stump is improved, and the development of large scar tissue within the muscle tissue can possibly be at least partly prevented by bringing the retracted muscle stumps closer together through (micro) surgical means. However, in the context of experimental studies, it should be noted that the suturation of the fascia does not prevent contraction of the ruptured muscle fibers or subsequent formation of large hematoma in the deep parts of the muscle belly.
Physical Therapy Management
When a quadriceps muscle strain occurs during a competition or training, it is important to react immediately. In the 10 minutes following the trauma one needs to put the knee of the affected leg immediately in 120° of flexion.   This avoids potential muscle spasms, reduces the hemorrhage and minimizes the risk of developing myositis ossificans  .Practically, this can be done by placing the patient in a hinged knee brace at 120° of knee flexion or using elastic compression wrap to maintain this position of flexion.If the knee is left in extension the healing process will be slower and more painful because the quadriceps will start to heal in a shortened position. 
The rest of the therapy during the healing process is based on the RICE therapy, this includes:
- Ice treatment
- Elevation 
Rest : Rest prevents worsening of the initial injury.By placing the injured extremity to rest the first 3-7 days after the trauma, we can prevent further retraction of the ruptured muscle stumps (the formation of a large gap within the muscle), reduce the size of the hematoma, and subsequently, the size of the connective tissue scar.  During the first few days after the injury, a short period of immobilization accelerates the formation of granulation tissue at the site of injury, but it should be noted that the duration of reduced activity (immobilization) ought to be limited only until the scar reaches sufficient strength to bear the muscle-contraction induced pulling forces without re-rupture. At this point, gradual mobilization should be started followed by a progressively intensified exercise program to optimize the healing by restoring the strength of the injured muscle, preventing the muscle atrophy, the loss of strength and the extensibility, all of which can follow prolonged immobilization. 
Ice or cold application : It is thought to lower intra-muscular temperature and decrease blood flow to the injured area.Regarding the use of cold on injured skeletal muscle, it has been shown that early use of cryotherapy is associated with a significantly smaller hematoma between the ruptured myofiber stumps, less inflammation and tissue necrosis, and somewhat accelerated early regeneration.   But according to the most recent data on topic (2007), icing of the injured skeletal muscle should continue for an extended period of time (6 hours) to obtain substantial effect on limiting the hemorrhaging and tissue necrosis at the site of the injury. 
Compression : This may help decrease blood flow and accompanied by elevation will serve to decrease both blood flow and excess interstitial fluid accumulation. The goal is to prevent hematoma formation and interstitial edema, thus decreasing tissue ischemia. However, if the immobilization phase is prolonged, it will be detrimental for muscle regeneration.  Cryotherapy, accompanied by compression, should be applied for 15–20 min at a time with 30–60 min between applications. During this time period, the quadriceps should be kept relatively immobile to allow for appropriate healing and prevent further injury.
Elevation : The elevation of an injured extremity above the level of heart results in a decrease in hydrostatic pressure, and subsequently, reduces the accumulation of interstitial fluid, so there is less swelling at the place of injury. But it needs to be stressed that there is not a single randomized, clinical trial to validate the effectiveness of the RICE-principle in the treatment of soft tissue injury.
Active Phase of Management
The acute phase of treatment is subsequently followed by an active phase of management once the injured leg is recovering well. This phase usually begins approximately 3–5 days after the initial injury depending on its severity. Stretching, strengthening, range of motion, maintenance of aerobic fitness, proprioceptive exercises, and functional training are the primary components of this phase.  .
- Stretching : Stretching should be done carefully and always to the point of discomfort, but not pain. Various techniques can be utilized including passive, active–passive, dynamic, and proprioceptive neuromuscular facilitation stretching. Generally, ballistic stretching is discouraged due to the risk of re-tearing muscle fibers. If it is pain free , stretch the quad muscles.
Static quad stretch :This can be performed in either standing, or laying on your front. Pull the foot of the injured leg towards your buttock until you can feel a gentle stretch on the front of the thigh. To increase the stretch, tilt your hips backwards. Hold for 20-30 seconds and repeat 3 times. Do this at least 3 times a day.
The aim of strengthening exercises is to gradually increase the load that is put through a muscle. Strengthening exercises can start as early as day 5 as long as they are low-level and must be done pain-free.Isometric or static exercises are advised first and then progress to dynamic exercises with resistance band and finishing with sports specific running and sprint drills. scientific evidence is lacking on the consensus of treatment principles of muscle injuries 
- Isometrics : Initial isometrics with quadriceps contractions done with the knee fully extended and in different positions at 20 degree increments as knee flexion improves May discontinue isometrics when patient can sit comfortable.
A quadriceps muscle strain is an acute tearing injury of the quadriceps.This injury is usually due to an acute stretch of the muscle, often at the same time of a forceful contraction or repetitive functional overloading. The quadriceps, which consists of four parts, can be overloaded by repeated eccentric muscle contractions of the knee extensor mechanism. Acute strain injuries of the quadriceps commonly occur in athletic competitions such as soccer, rugby, and football. These sports regularly require sudden forceful eccentric contraction of the quadriceps during regulation of knee ﬂexion and hip extension. Higher forces across the muscle–tendon units with eccentric contraction can lead to strain injury. Excessive passive stretching or activation of a maximally stretched muscle can also cause strains. Of the quadriceps muscles, the rectus femoris is most frequently strained. Several factors predispose this muscle and others to more frequent strain injury. These include muscles crossing two joints, those with a high percentage of Type II ﬁbers, and muscles with complex musculotendinous architecture. Muscle fatigue has also been shown to play a role in acute muscle injury.