Posts in patellofemoral pain
Treating Knee Pain in Runners

As the snows melts many of us will return to the amazing Boulder trail system for our training runs.  This popular form of exercise comes with tremendous health benefits, but can also place some runners at risk for running injuries such as knee pain.  Patellofemoral Pain (pain on the front of the knee) is the leading cause for medical consultation attributed to a running program (Taunton et al. 2002).  

Authors have suggested multiple reasons for the pain including training errors (too much volume, too soon), weakness and/or tightness in lower body muscles, and poor control of the lower extremity during the running gait cycle.  Loads on the knee joint have been measured at 4-5 times body weight during running (Roos et al. 2012) with higher loads noted in runners with knee pain (Davis et al. 2010).  Physical Therapy remains the gold standard for treatment of this disorder due its' unique ability to identify and treat the specific factors contributing the symptoms in this group of athletes. 

Prior research on knee pain in runners has shown gait retraining to be an inexpensive and effective treatment for reducing pain and improving function.  In particular, cuing to to improve step frequency and to land softer can significantly reduce impact forces at the knee during running.  A recent article in the Journal of Sports Rehabilitation expands on this research and highlights the impact of a multimodal treatment program for runners with knee pain (Esculier et al. 2016).

The authors included 21 runners with > 3 months of knee pain who were running at least 15 km per week.  These runners must have at least 3/10 pain with running and report pain with stair climbing, kneeling and squatting to be included in the study.  All of the runners were evaluated by a Physical Therapist for their running gait as well as an assessment of strength, flexibility, and control of their knee during functional testing.  Each runner underwent treatment for 8 weeks based on this initial examination performing exercises at home in addition to treatments with the Physical Therapist.  Runners were instructed to increase their step frequency to reduce the loading on their knees, as well as, to land softer to reduce the vertical loading on their legs.  

75% of the runners reported success with improved knee pain and function following the treatments.  Interestingly, the 5 runners who reported low to moderate success did not demonstrate significant changes in the forces across the knee at the end of the trial.  These athletes may require further gait retraining to make a significant impact on their symptoms.  

This study highlights the importance of running gait retraining, without the need for expensive bio-mechanical equipment, and strengthening exercises on improving pain and function among runners.  To learn more about how you can improve your knee pain and get back to running contact your local Physical Therapist.   

 

Physical Therapy Treatments for Knee Pain

The internet is excellent at providing information on a multitude of subjects, but the application of this information is limited because of the existence of individual situations and people.  An example of this would be the failure of a one size fits all approach to Physical Therapy.  In this example, every patient with a certain diagnosis would be given the same treatment regardless of their presentation.  This approach has led to higher costs and poor outcomes in the Physical Therapy research.  Conversely, examining each patient and providing specific treatments to match their presentation has been shown to improve outcomes for many conditions including low back pain.  

Pain on the front of the knee, anterior knee pain or patellofemoral pain, is a common source of knee pain in the active population.   Patients with this diagnosis often present with impairments in flexibility and/or strength at the adjacent joints in the hip and ankle.  These impairments above and below the knee joint can affect both the mechanics and loading of the leg during activity.  The multifactorial nature behind knee pain limits our ability to find a one size fits all treatment option.  Instead new research is identifying sub groups of patients with knee pain to improve our ability to study and treat these patients.  

In a recent issue of the British Journal of Sports Medicine authors studied 130 patients with anterior knee pain and placed them through a Physical Therapy examination (Selfe et al. 2016).  The authors broke these patients with knee pain into 3 sub groups based on the examination findings.  The groups included strong (29 patients), weak and tight (49), and weak and pronated feet (49).  Each group consisted of individual exam items which either precipitated or perpetuated their knee symptoms.  For example, in the weak and pronated foot group authors found weakness throughout the lower body likely contributing to the poor mechanics during activity seen in this group of patients.  Future research is needed to determine if these subgroups lead to more specific and impactful treatments as seen in the low back pain research.

Patients with knee pain are encouraged to avoid a one size fits all exercise approache and instead use a local Physical Therapist to identify impairments like flexibility and/or strength leading to reduced costs and improved outcomes.   

How Deep Should I Squat?
how-deep-should-I-squat

The squat may be one of the best exercises for the development of strength and mobility through the lower quarter of the body.  It is often used as the foundation of strength training by both recreational athletes and pro athletes alike.  I often use the squat in our Physical Therapy practice with patients recovering from arm, leg, or spine injuries as they progress through their rehabilitation programs.  The squat's multi joint nature requires a tremendous amount of coordination and proper technique to avoid compensatory movements which may place an individual at risk of future injury.  No where is this more apparent than in our young athletes asked to perform olympic lifting without proper training in technique. 

After an athlete returns to activity a common question we receive is how deep should I squat?  The easy answer is it depends, but in a healthy athlete there is no risk of squatting below parallel thighs.  At 90 degrees of knee bend the highest amounts of joint pressure are placed across the knee, but deeper squats do not increase this pressure (Hehne et al. 1990).  Patients who stop at one quarter or one half the distance to the floor likely require greater weights in order to stimulate the physiological changes consistent with muscle hypertrophy or strength development.  This increase in weights increasing the loading on the spinal and knee joints compared to a lighter weight used through the full range of motion in the deep squat.  Conversely, working through a deeper range of motion, given proper technique, has been shown to improve load distribution through the leg and reduce forces at the knee (Hartmann et al. Sports Medicine. 2013).

Athletes with patellofemoral pain, pain on the front of the knee, or knee osteoarthritis should limit their squat depth to one quarter.  Avoiding this degree of movement will reduce forces across the knee joint.  Healthy athletes should work through their available range of motion to maximize strength and performance gains.  To learn more about how the squat can improve your strength and performance or safely strengthen your legs after a knee injury contact your local Physical Therapist.   

Economic Cost of Running Injuries

Mend Physical Therapy has previously written on the prevention and treatment of running injuries  in multiple prior blog posts.    Running is very common form of exercise in the United States and here Boulder County. The vast majority of runners will sustain an injury in the upcoming year which will prevent them from training or competing at their intended levels.  Our prior posts have described the risk factors for these injuries and our ability to prevent them.  In particular, having a twice a week running specific strengthening program and a Physical Therapy assessment of your running gait may create the biggest impact and keep you on the trails.  

Once an injury is sustained an athlete faces an impact on both his or her training and possibly their finances.  These may be in the form of changes in footwear, running coaches, gait analysis, physical therapy visits, diagnostic tests, etc.  A recent article in the Scandinavian Journal of Medicine and Science in Sport documented the economic impact of running related injuries among athletes training for an upcoming race event (Junior, L. 2015).

Junior et al. followed 53 runners training for an upcoming 5K, 10K, or 10 mile race.  All runners participated in run training programs put on by the upcoming race events.  These programs consisted of written materials on race preparation and weekly supervised group run training sessions based on experience and ability levels.  The supervised program consisted of a warm up, cool down, and 60 minutes of run training over 5-10K focused on speed development.  

Over half, 32 out of 59 runners, sustained a running related injury during the training period with 85% of these injuries being classified as overuse in nature.  Interestingly, the authors noted a higher percentage of running injuries in the experienced group compared to those with <1 year of running experience.  Of the running related injuries, 73% caused athletes to miss upcoming training sessions and 34% lead athletes to seek medical attention.  These individuals sought medical attention from their primary care MD or a medical specialist, with 38 receiving Physical Therapy care.  

The economic impact of these injuries among these 53 runners was significant.  $6200 was spent on these 32 athletes, 66% of this cost (direct cost) went towards direct health care consultations.  Each injury was broken down into a direct cost and an indirect cost due to lost time from work.  The indirect costs from loss of work time were twice that of those directly related to health care consultations.  Due to the high financial impact of running injuries, the authors recommend runners be given injury prevention programs to prevent health care expenses and time off of work due to injury.  

To learn more about how you can prevent injuries contact the experts at Mend Physical Therapy

Running Foot Strike Patterns and Injury Risk

Our previous blog post detailed the differences in biomechanics between foot strike patterns in runners.  There are clear bio mechanical differences between utilizing a forefoot and rear foot strike pattern and these are important for gait retraining and injury risk.  Obviously, the foot is the first part of the body to strike the ground in running and this impact transmits forces through the lower quarter.  For example, a fore foot versus rear foot striker would have more knee flexion or extension at impact, respectively.  This would require greater or lessor work from the quadriceps to control this impact.  When we consider the number of strides taken in a runner's mile, up to 2000 strides per mile depending on speed, we can gain an appreciation of the repetitive loading which may predispose a runner to different injuries based on their stride frequency and foot strike pattern.  

running, heel strike pattern, physical therapy gait analysis
running, forefoot strike pattern, physical therapy running analysis

A recent article in the American Journal of Sports Medicine examined the impact of stride frequency and strike patterns on injury predictors in running (Boyer et al. 2015).  The authors examined 42 runners (50% rear foot, 50% mid foot) as they ran between 7 and 8 miles per hour at their self selected stride length then at both 5 and 10% shorter lengths.  The authors noted changes in biomechanics within runners when they shortened their strides consistent with a greater stride frequency to maintain the 7-8 mph speed.  Iliotibial (IT) band strain did not differ between forefoot and rear foot strikers but did increase when runners reduced their stride length (greater knee flexion).  A reduction in both pelvic drop and knee adduction, which we commonly see in overuse injuries of the lower quarter in runners, was reduced when runners increased their stride frequency and decreased their stride length.  The authors concluded that one foot strike pattern was not better than another, but rather the step rate and stride length has a greater impact on these biomechanics variables.  

Consistent with our understanding on running injuries and biomechanics, there is not one preferred strike pattern for the foot but rather the amount of time an athlete spends in contact with the ground as well as stride variables (step length and rate) may have a greater impact on injury.  To learn more about your running gait and its' impact on performance and injury risk contact the experts at Mend.  

Forefoot vs. Rear foot Strike Patterns and Biomechanics in Running

Running Mechanics

Running is one of the most common forms of exercise and has grown in popularity as evidenced by the wide range of age and ability levels running in Boulder County.  Unfortunately, injuries effect a significant number of athletes with up to 90% reporting a prior injury(1). The vast majority of these injuries are over use in nature including plantar fasciosis, achilles tendonosis, or shin pain.  The high number of injuries associated with running has driven many researchers and clinicians to search for effective methods to reduce injury risk among runners.  In particular, recent evidence has documented the effectiveness of real time feedback provided by Physical Therapists in reducing pain and improving running form(2).  One aspect a Physical Therapist may examine is the strike pattern of a runner and how this impacts the biomechanics of the lower quarter for both injury risk and performance. 

physical therapy feedback, running gait retraining

A recent systematic review of the literature gathered evidence to quantify the biomechanics occurring at the lower extremity with different foot strike patterns.  Almeida et al. and colleagues reviewed the literature on foot strike patterns during running to compare and contrast the changes noted in fore and rear foot strikers (3). 

running-heel-strike-biomechanics-forces

These two pictures above demonstrate the relative changes in lower extremity joint range of motion and loading between the two strike patterns in runners.  Each strike pattern can be associated with different injuries in the lower extremity (detailed below) based on impact forces during running.  Also of importance would be the frequency of the stride.  Runners with a slower stride frequency would spend a higher relative time in stance phase and thus have a greater transmission of forces through the lower quarter.  

running-fore-mid-foot-mechanics-forces
running strike patterns and injury risk, physical therapy boulder

In conclusion, a runner's form is largely self selected and there is not a "perfect" running form, but knowing the biomechanics of the two strike patterns can influence decision making for improving  performance and reducing injury risk. 

References

1. Yamato TP, Saragiotto BT, Hespanhol Junior LC, Yeung SS, Lopes AD. Descriptors used to define running-related musculoskeletal injury: a systematic review. J Orthop Sports Phys Ther. 2015;45:366-374. 10.2519/jospt.2015.5750 

2. Agresta, C. et al. Gait retraining for injured and healthy runners using augmented feedback. A systematic literature review. JOSPT. 2015. 45(8):576-584. 

3. Almeida, A. et al. Biomechanical differences of foot strike patterns during running: A systematic review with meta analysis. JOSPT. 2015.