High Ankle Injuries – Syndesmosis Injury vs Lateral Ligament Injuries

High Ankle Injuries or Syndesmosis injuries are important to be diagnosed correctly as the management and return from injury is very different to that of the common lateral ligament ankle sprain.

Anatomy

The lateral ligaments of an ankle and the syndesmosis ligament (anteriorly) are in close anatomical proximity to each other. This is why a lateral ligament ankle sprain can be mistaken for a syndesmosis injury.

Syndesmosis complex (in RED) consists of the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL), interosseous ligament (IOL), and the inferior transverse ligament (ITL). Its function is to hold the lower leg bones together – the tibia and fibula, so the ankle joint remains stable.

The lateral ligaments (in BLUE) consist of the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL).

How Are They Injured?

Syndesmosis Injury – Forced External Rotation of the ankle. Most commonly the force from an opponent landing on the outside of the lower leg, causing the ankle to be forced into external rotation (toes pointed outwards). This causes the fibula and tibia to be separated at the ankle and injuring the syndesmosis complex.

Lateral Ligament Injury – Ankle Inversion +/- Plantar Flexion. Most commonly from a landing from a jump or changing direction causing the ankle to roll inwards. Some other factors can contribute to this cause are landing from a jump onto an opponent’s foot and rolling off it or rolling an ankle because of a divot in the ground. This causes the lateral ligaments to stretch and be injured.

Diagnosis of the Injuries

Important and accurate diagnosis is required by a trained Sports & Exercise Physiotherapist as the management varies between syndesmosis injuries versus lateral ligament injuries and the severity of if the injuries.

These injuries are diagnosed by understanding how the patient injured themselves (See pictures above). A clinical examination is performed by a trained physiotherapist, who will differentiate the two types of injuries and the severity of the injuries.

Syndesmosis injuries are classified into 4 grades:

Grade 1: Isolated injury to AITFL

Grade 2: Injury to AITFL and IOL

Grade 3: Injury to AITFL, IL and PITFL

Grade 4: Injury to AITFL, IL, PITFL and Deltoid Ligament.

Correct diagnosis can and should be confirmed with a MRI if suspicious of more than a grade 2 injury. Of the radiographic tools, MRI has been found to have the highest specificity and sensitivity – meaning the most accurate form of imaging available. X-Ray is used to rule out fractures/breaks in bones. The reliability of x-ray, particularly using stress radiographs to diagnose injury to the ankle syndesmosis is controversial.

Lateral ligament most commonly injured is the ATFL and then the CFL.  PTFL are less likely to sustain damaging loads. Combination of the ligaments can also be injured.

Lateral Ligament Injuries are classified into 3 grades:

Grade 1: Microscopic injury without a partial tear

Grade 2: Macroscopic injury - Partial tear to ligament

Grade 3: Complete rupture to the ligament

These all present with different varying grades of symptoms. X-Ray can be used the exclude any acute bony injury and MRI can confirm the ligaments injured and the grading of these ligaents. MRI is usually only performed in a more serious presentations or where suspicion to other structures of the ankle such as talar dome may be injured.

Management 

Syndesmosis Injuries

 Syndesmosis injuries require a period of biological healing for the ligament before loading occurs. This ligament is loaded through weight-bearing and walking and therefore requires a period of time of off-load to allow healing to occur.

Usually grade 1 and grade 2 injuries are managed without surgery. They are put in a boot and are non-weight-bearing for a period of time depending on the grade. Management of swelling is important with compression, massage and ice. They are then weaned out of the boot and graded ROM, strength, balance of the ankle/foot is performed. This progresses to more functional rehab such as plyometrics, running mechanics, running and sport/exercise specific rehab when able. The rehab timelines for a grade 1-2 is usually 5-10 weeks depending on the patient’s presentation. 

Grade 3 injuries and sometimes grade 2 injuries can be surgically stabilised by a tight rope or screws. Rehab management again is a graded process working on ROM, strength, balance and functional progressions. The rehab timeline for a tightrope surgical stabilisation is usually 8-16 weeks.

Lateral Ligament Injuries

Management is similar to that of a syndesmosis ankle injury however rehab timelines are far quicker because the ligaments are non-weight bearing ligaments. Rehab timelines are purely based on competency-based progressions where, if the patient can walk with minimal symptoms, get them to walk. Get them doing as much ROM, strength and functional rehab within what symptoms allow.

Rehab timelines are dependent on how many of the lateral ligaments are injured at once. If ATFL ligament injured in isolation the time frames may be from 3 days to 6 weeks depending on the severity/grade of injury. With two ligaments injured usually ATFL and CFL, usually this is a more severe injury may be 2-8 weeks.

What do you do if you have an ankle injury?

Book in for a consultation with one of our physiotherapists, so a correct diagnosis can be made to ensure a safe and timely return to your activity or sport.  

Patella & Quadriceps Tendinopathies

Tendon injuries of the knee commonly occur of sports that require sprinting, change of direction and kicking. Patella and quadriceps tendons are less common injured in runners but do still occur. These tendon injuries occur for different reasons compared to other Runners Knee Injuries and need to be managed differently.

Causes

Runners Knee tendinopathies occur when running loads are very high or increased suddenly. They more often occur with running of increased speed or intensity and are more common in sports that require sprinting and jumping and landing.

Tendon injuries occur when there is a mismatch between tendon capacity (i.e what the tendon is capable and accustomed to doing) and the load placed on it (i.e the training stimulus) (Cook and Purdam, 2009). – See Jumpers Knee: Patellar Tendinopathy – Diagnosis & Management in our news section for further discussion on this topic https://www.hprsphysio.com.au/news/2018/1/11/diagnosis-management-of-jumpers-knee-patellar-tendinopathy.

Diagnosis

As with other running related knee injuries a thorough assessment and diagnosis from your Sports Physio or Sports Doctor is the first step. Often on looking back at your running history it will become obvious there is a recent spike in your workload over a relatively short period of time. Pain directly over your quadriceps tendon insertion or patella tendon origin at the inferior point of your knee cap, as well as a history of a spike in running load is common. Morning pain and stiffness are also key diagnostic features of these tendinopathies.

It is important to get a diagnosis of the phase of injury you have in your tendon as they are management different. Eg, a new acute injury is managed differently to a chronic overuse injury. A sports physio will help determine which phase of injury your tendon is in. Imaging can be used to assist this diagnosis but is not always accurate.

Management

Overuse tendon injuries around the knee respond well to strength work and running program modification.

Strength is very effective in these injuries to reduce pain and improve performance, but needs to be programmed individually to the injury and their running demands.

Relative rest may also be indicated for acute reactive tendon injuries to the patella or quadricep, but you should not completely cease running as the overall capacity (strength) of the tendon will decrease making this injury susceptible to recurrence (Kountouris & Cook, 2007).

Strength

Strengthening of the lower limb muscles, in particular the quadriceps, is the main form of management for these tendinopathies. Strength work consists of through range strength exercises where able and ISOMETRIC Strength exercises.

Isometric strength is where an exercise is held static for an extended period of time. Research has shown isometrics to be effective in reducing tendon pain for hours (Cook & Purdam, 2014; Cook, Rio & Docking, 2014). Specific isometric exercises for Patella and Quadriceps Tendiopathies include leg extension and leg press (See Pictures).

Isometrics are thought to work by maximally activating a large portion of the quadriceps muscles therefore taking load off the painful tendon. Working up to 3-4 sets of 45 seconds of heavy isometric holds is the aim here. These can be done pre and post running, as well as on days off as needed.

Leg Extension

Leg Press

Running Programming

Once your patella or quad tendon are acutely reactive and painful, the type and frequency of running you do needs to be addressed. A short relative rest period may be necessary initially to allow to tendon to settle. However, you should not rest completely for a long period of time as this with reduce your strength and the capacity of your tendon to run in the future. At the early stage you may be restricted to running only twice per week, ideally with a 2-3 day break between sessions. Tendons have been shown to take up to 72 hours to recover from a bout of intense exercise.

Other factors to consider when running with a tendon injury are;

-       Listen to your pain levels. It is generally ok to run with a pain of up 3/10. Pain greater than this during/after or the next day should be addressed

-       Minimal stretching. This can aggravate your injury

-       Pain killers and anti-inflammatory drugs can assist in symptom management, and used under the advice of a pharmacist or doctor. There is also some evidence that green tea and fish oil is helpful in tendon injuries (Fallon & Purdam et al. 2008).

Written By Chris Bailey - Titled Sports & Exercise Physiotherapist

References

Cook, J., Khan, K., Kiss, Z., Purdam, C., and Griffiths, L. (2001). Reproducibility and clinical utility of tendon palpation to detect patellar tendinopathy in young basketball players. British Journal of Sports Medicine, 35, 65–69. doi: doi:10.1136/bjsm.35.1.65

Cook, J.L, and Purdam, C.R. (2009). Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load induced tendinopathy. British Journal of Sports Medicine, 43(6), 409-16.

Cook, J., and Purdam, C. (2014). The challenge of managing tendinopathy in competing athletes. British Journal of Sports Medicine, 48, 506–509. doi:10.1136/bjsports-2012-092078

Cook, J., Rio, E., and Docking, S. (2014). Patellar tendinopathy and its diagnosis. Sport Health, 32(1), 17-20. Retrieved from: http://0-search.informit.com.au.alpha2.latrobe.edu.au/documentSummary;dn=322863309596697;res=IELHEA

Fallon, K., Purdam, C., Cook, J., Lovell, G. (2008). A ‘‘polypill’’ for acute tendon pain in athletes with tendinopathy? Journal of Science and Medicine in Sport, 11, 235—238. doi:10.1016/j.jsams.2007.09.002

Malliaras, P., Cook, J., and Kent, P. (2007) Anthropometric risk factors for patellar tendon injury among volleyball players. British Journal of Sports Medicine, 41(4), 259–263. doi:10.1136/bjsm.2006.030049

Kountouris, A., and Cook, J. (2007). Rehabilitation of Achilles and patellar tendinopathies. Best Practice & Research Clinical Rheumatology, 21(2), 295–316. doi:10.1016/j.berh.2006.12.003

Iliotibial Band Friction Syndrome

Introduction

Iliotibial band syndrome (ITBS) is the second most common RRI and the most common cause of lateral knee pain in runners.[3]

ITB Syndrome Anatomy

Cause

The aetiology of ITBS is thought to be multifactorial and remains poorly understood however several biomechanical risk factors have been proposed to contribute to the condition.[4] Traditionally, ITBS was thought to be caused by friction or excessive pressure at the distal iliotibial band (ITB) as it passes over the lateral femoral epicondyle during repetitive knee flexion and extension. [5] A more recent theory suggests that impingement at this site contributes to the condition rather than purely excessive lateral pressure.[6, 7]

Biomechanical Risk Factors

Proposed biomechanical risk factors for ITBFS include increased peak hip adduction,[8] knee internal rotation,[8-10] peak trunk ipsilateral flexion,[10, 11] and peak rearfoot pronation[12] as these factors can increase abnormal lengthening of the ITB (i.e. excess strain) and contribute to compression of the ITB at the lateral femoral condyle (i.e. excess stress).[13]

Poor Biomechanincs (Right) can contribute to ITBS

Prevention and Management

Preventative measures for ITBFS should include an appropriate training plan that includes gradual increases in running distance and appropriate load management strategies including programmed rest days and de-load phases.[2]

Management

The acute management of ITBS should focus on anti-inflammatory modalities, relative rest, soft tissue release and addressing biomechanical factors known to contribute to ITBS.[13] As irritability settles running can be gradually re introduced in line with a periodised running plan. Running retraining incorporating running with an increased cadence has been shown to increase the gluteal muscle recruitment during foot strike and mid stance of the running cycle [14] and may help to decrease load at the ITB insertion in patients with ITBS.

There is debate as to whether it is possible to modify running mechanics with strengthening exercises alone however positive results have been demonstrated in studies that focus on isometric and eccentric strength of the glute muscles in running specific positions[15] and include visual feedback with cueing.[16] The hip abductor muscles are known to contribute to peak hip adduction, knee internal rotation, ipsilateral trunk flexion[17] and have been shown to be related to other lower limb RRI’s.[14] Two gluteal muscles that control frontal and transverse plane hip and pelvic motion during running include the glute max and glute med.[14] Glute max EMG is shown to be highest in the step up and single leg squat exercise while the glute med EMG is shown to be highest in the side bridge with hip abduction exercise [18] (See Pictures Below). Despite a lack of prospective research it is plausible to include gluteal strengthening 2-3 x per week in the management of ITBS given the gluteal muscles’ relationship to biomechanical factors known to be associated with the condition.

While foot and ankle orthosis have been proposed as a tool to maintain a neutral foot position and control tibial internal rotation during running[19] to date, no prospective studies have investigated the use of orthosis for patients with ITBS.

Single Leg Squat

Side Bridge with Hip Abduction

Conclusion

Based off the available evidence the best management for ITBS includes appropriate management in the acute stage to settle irritability followed by gluteal strengthening with an emphasis on isometric and eccentric frontal and transverse plane movements and physiotherapist guided running retraining.

Take Away Points

·      ITBS is the second most common RRI and the most common cause of lateral knee pain in runners.

·      ITBS is thought to be caused by either excessive lateral pressure or impingement as the ITB runs over the lateral femoral epicondyle during knee flexion and extension.

·      Gluteal weakness is proposed as a modifiable contributing factor in ITBS.

·      Gluteal strengthening should focus on isometric and eccentric exercises in running specific positions and should be carried out with appropriate cueing and visual feedback.

·      Running retraining including running with an increased cadence has been proposed to increase gluteal muscle activation during running.

Written by Cameron Dyer – Physiotherapist and Athlete Rehab Specialist

References

1.         Videbæk, S., et al., Incidence of Running-Related Injuries Per 1000 h of running in Different Types of Runners: A Systematic Review and Meta-Analysis. Sports Medicine, 2015. 45(7): p. 1017-1026.

2.         van Gent, R.N., et al., Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. British Journal of Sports Medicine, 2007. 41(8): p. 469-480.

3.         Taunton, J.E., et al., A retrospective case-control analysis of 2002 running injuries. British Journal of Sports Medicine, 2002. 36(2): p. 95.

4.         Beers, A., et al., Effects of Multi-modal Physiotherapy, Including Hip Abductor Strengthening, in Patients with Iliotibial Band Friction Syndrome. Physiotherapy Canada. Physiotherapie Canada, 2008. 60(2): p. 180-188.

5.         Orchard, J.W., et al., Biomechanics of Iliotibial Band Friction Syndrome in Runners. The American Journal of Sports Medicine, 1996. 24(3): p. 375-379.

6.         Hamill, J., et al., A prospective study of iliotibial band strain in runners. Clinical Biomechanics, 2008. 23(8): p. 1018-1025.

7.         Fairclough, J., et al., Is iliotibial band syndrome really a friction syndrome? Journal of Science and Medicine in Sport, 2007. 10(2): p. 74-76.

8.         Noehren, B., I. Davis, and J. Hamill, ASB clinical biomechanics award winner 2006 prospective study of the biomechanical factors associated with iliotibial band syndrome. Clinical biomechanics (Bristol, Avon), 2007. 22(9): p. 951.

9.         Ferber, R., et al., Competitive female runners with a history of iliotibial band syndrome demonstrate atypical hip and knee kinematics. The Journal of orthopaedic and sports physical therapy, 2010. 40(2): p. 52.

10.       Foch, E., et al., Associations between iliotibial band injury status and running biomechanics in women. Gait & Posture, 2015. 41(2): p. 706-710.

11.       Foch, E. and C.E. Milner, The influence of iliotibial band syndrome history on running biomechanics examined via principal components analysis. Journal of Biomechanics, 2014. 47(1): p. 81-86.

12.       Messier, P.S., et al., Etiology of iliotibial band friction syndrome in distance runners. Medicine & Science in Sports & Exercise, 1995. 27(7): p. 951-960.

13.       Baker, R.L. and M. Fredericson, Iliotibial Band Syndrome in Runners: Biomechanical Implications and Exercise Interventions: Biomechanical Implications and Exercise Interventions. Physical Medicine & Rehabilitation Clinics of North America, 2016. 27(1): p. 53-77.

14.       Semciw, A., R. Neate, and T. Pizzari, Running related gluteus medius function in health and injury: A systematic review with meta-analysis. Journal of Electromyography and Kinesiology, 2016. 30: p. 98-110.

15.       Fredericson, L.M., et al., Hip Abductor Weakness in Distance Runners with Iliotibial Band Syndrome. Clinical Journal of Sport Medicine, 2000. 10(3): p. 169-175.

16.       Barrios, J.A., K.M. Crossley, and I.S. Davis, Gait retraining to reduce the knee adduction moment through real-time visual feedback of dynamic knee alignment. Journal of Biomechanics, 2010. 43(11): p. 2208-2213.

17.       Mucha, M.D., et al., Hip abductor strength and lower extremity running related injury in distance runners: A systematic review. Journal of Science and Medicine in Sport, 2017. 20(4): p. 349-355.

18.       Macadam, P., J. Cronin, and B. Contreras, An examination of the gluteal muscle activity associated with dynamic hip abduction and hip external rotation exercises. A systematic review. International journal of sports physical therapy, 2015. 10(5): p. 573.

19.Aderem, J. and Q.A. Louw, Biomechanical risk factors associated with iliotibial band syndrome in runners: A systematic review Rehabilitation, physical therapy and occupational health. BMC Musculoskeletal Disorders, 2015. 16(1): p. <xocs:firstpage xmlns:xocs=""/>.

Patellofemoral Pain Syndrome (PFPS)

PFPS is the most common cause of knee pain in runners. It is characterised by an ache directly under or around the knee, which often worsens the further you run. The injury is also prone to recurrence and chronic pain. This PFPS can be managed successfully in the short term, but often causes longer term issues as once the symptoms subside people cease managing what causes the pain (Davis and Powers, 2009). PFPS is more common in females, and more likely to occur in adolescence.

Causes

The cause of PFPS is commonly multifactorial.

As with other running injuries the causes are from biomechanical sources:

• from the knee, hip and/or foot,

• or from running overload, or a combination of both.

Knee

Poor tracking of the kneecap (Patella) in the knee grove (Trochlear grove) can occur locally at the knee. Over time this creates more load over a smaller surface area of the knee leading to pain. This maltracking can be contributed to by the anatomy of the knee, or hyper-mobility, or simply due to weakness of the quadriceps muscles.

Hip

The angle of the hip can contribute to the amount of load going through the anterior knee, as can the strength of the muscles around the hip. If the gluteal muscles in particular are weak, or do not switch on quick enough, this can lead to PFPS during activities such as running or going downstairs.

Foot

People with flatter (or pronated feet) can be more prone to anterior knee pain. Having pronated feet causes the knee to turn in which places greater load on the patella and leads to pain. A combination of simple orthotics and strength work around the foot can improve the biomechanics in the knee above and an improvement in PFPS.

Management

PFPS management will depend on which of the above issue(s) are contributing to your runners’ knee. Most commonly you need to address a combination of these factors to improve your pain. Ultimately management will depend on a through and accurate assessment of the causes of your PFPS.

For the Knee local strength work and McConnell strapping is effective in improving the knee maltracking and relieving symptoms. Runners with greater strength have been found to be less prone to anterior knee pain with running (Duffey et al, 2000). In particular quad strength.

Patellofemoral Joint Strapping

For the Hip the gluteal muscles are targeted with strength work. Exercises such as hip thrusts, crab walk and bridges target glute strength. This will decrease the load placed on the anterior knee when running.

Barbell Hip Thrust

For the Foot, orthotics and foot intrinsic muscle work will improve lower body tolerance of pounding the pavement and get the knee in a better position to decrease the load through the Patellofemoral Joint.

Practical Tips

Strength Work - Address your strength deficits. Whether it’s weakness around your knee, hip and/or foot strength work here will improve your running.

Strapping - For local knee tracking issues

Orthotics - Even generic orthotics can be very effective in helping alleviate PFPS if identified as a cause.

Sports Physio or Sports Doc - See a professional to assess the above and help design a plan to get you pain free with running.

Written By Chris Bailey - Titled Sports & Exercise Physio

References

Irene Davis & Christopher Powers (2009). Patellofemoral Pain Syndrome: Proximal, distal and local factors. Journal of Orthopaedic and Sports Physiotherapy.

Michael Duffey Et Al (2000). Etiologic factors associated with anterior knee pain in distance runners. Medicine & Science in Sport & Exercise

Anterior Knee Pain (Aka Runners Knee)

Runners Knee

Runners Knee is a broad term used to describe pain that occurs across the front of the knee in runners. This can be caused by many different anatomical sources and is the most common injury experienced by runners.

Most Common Knee Injuries

The most common Runners Knee injuries are

-       Patellofemoral Pain Syndrome (PFPS)

-       Iliotibial Band Friction Syndrome (ITBFS)

-       Patella and Quadriceps Tendinopathies

-       Joint Pain (OA or Cartilage Injuries)

Causes

There are 2 major factors that commonly contribute to anterior knee pain:

-       Biomechanical Factors – that is the way that you run. Often due to lack of strength or anatomical factors.

-       Running Overload – this is caused by running too frequently or increasing your running volume too quickly, or both.

Biomechanical Factors

Biomechanical factors contributing to anterior knee pain can arise locally in the knee, or from the hip joint above, or the foot below.

Locally the knee may have poor quads strength which leads to poor tracking of the kneecap (patella) and pain. Other factors include anatomical issues such as hypermobility, or a shallow track (femoral trochlea) which causes overload in the patella and pain.

The hip joint commonly contributes to knee pain if the glutes are weak (Davies and Powers, 2009). Another cause is increased hip width which translates to more load in the anterior knee, this is one reason why females are more prone to these injuries.

In the foot flatter (pronated) feet can make you more susceptible to anterior knee pain with running.

Running Overload

The training principle of progressive overload needs to be considered when planning how to progress your running. That is, to get fitter or run further you need to increase your running with greater than normal loads. This should be done gradually over an extended period of weeks or months depending on the individual and their goals. There is no magic number here but increasing by between 5-20% initially is usually safe. If running frequency or running volume is increased too quickly, you are at a higher risk of injury.

Recovery periods in your training blocks will also decrease risk of injury.

Management

Management of Runners Knee will depend on the location and cause of pain. It is also important to identify the contributing factors for your injury as this will guide the management needed.

Post running muscle soreness and tightness is normal after progressing running and unaccustomed exercise. Often stretching/mobility/foam rolling, and other recovery modalities can address this soreness and allow you to keep running.

If your pain is acute, single sided and/or stops you from running it should be addressed by seeing a Sports Physio or Sports Doctor.

Management may include any or all of the following; specific strength work, mobility exercises, strapping, and orthotics to address the cause of your injury. It’s also important to map out a running plan that is tailored to you and specific to your goals and injury.

PRACTICAL TIPS

Mobility/foam rolling – Of your lower body, often quads and hips are target areas.

Strengthening – Quadricep and Gluteal strength work is usually targeted for these runners injuries.

Foot/Ankle – Strength work to improve your balance or arch strength. Wearing the appropriate shoes for your foot type.

Written by Chris Bailey - Titled Sports and Exercise Physio

Returning to Run Programs – What, Why, When and How

Have you been told by a physio to complete a ‘return to run’ program before returning to sport?

This article will answer all your return to run program questions including:

·       What it is?

·       Why it is important?

·       When it is appropriate?

·       What should it include?

·       How long should it last?

What is it?

A return to run (RTR) program is a series of running progressions that aims to prepare the athlete returning from injury for the demands of a running based sport. As such, a well-designed return to running program should:

1.     Consider the injury and the demands of the sport

2.     Restore efficient running mechanics

3.     Ensure the athlete is appropriately prepared for the running demands of a running based sport

Why is it important?

A RTR program is important for two main reasons:

1.     Running is often either the cause or a contributing factor to why the initial running related injury occurred. Efficient running technique has been shown to both improve performance and reduce the risk of running related injuries therefore efficient running shoulder be restored prior to returning to sport.

2.     Running is a potent stimulus on the body with 5-8 x bodyweight load shown to be absorbed by the body during running. As such, running must be restored gradually while respecting principles of recovery and tissue adaptation. If you return to running too quickly after an injury you may be at risk of sustaining a subsequent or recurrent injury.

When is it appropriate?

A RTR program is appropriate for any injury where the athlete is required to run as part of their sport. For example, an ACL injury in a soccer player, a hamstring injury in a rugby player or a stress fracture in a netball player should all progress through some form of a RTR program due to the running based nature of these respective sports.

What should it include?

A RTR program should be designed based on the specific injury and the demands of the sport that the athlete is returning to. In saying this, RTR programs should generally include components of each of the following areas:

1.     Warm Up - Goals of this phase are to raise the core body temperature and increase blood flow to working muscles. Example: Slow jog 2 x 1:00

2.     Dynamic mobility - Goals of this phase are to increase range of motion at key areas of the body specific to running i.e. hip, lumbar spine, hamstring. Example: Leg swings, dynamic lunge, hamstring sweep.

3.     Activation - Goals of this phase are to teach the athlete to effectively activate key muscle groups in running specific positions i.e. calf / achillies, glute, hamstring, trunk. Examples: Skipping, wall drills, step to base drills

4.     Running mechanics - Goals are to expose the athlete to efficient running positions and postures and to practice efficient running mechanics in low load cyclical drills. Examples: A skip, A run + progressions

5.     Running content

a.      The specific content of a return to run program is based off the injury and demands of the sport that the athlete is returning to.

b.     When planning content of a return to run program the physiotherapist should consider the following categories and program according to their importance to the individual’s sport:

                                               i.     Straight line running

                                              ii.     Change of direction (COD)

                                             iii.     Agility

                                             iv.     Acceleration / deceleration

                                              v.     Sprinting

                                             vi.     Conditioning

                                            vii.     Sport specific drills

c.      In addition, the physiotherapist should monitor the overall volume of running particularly the volume and intensity of high-speed running to ensure loads are progressed appropriately.

How long should it last?

There is no set length of time that an athlete should complete a RTR program for. The duration of a RTR program should be made with the athlete, the physiotherapist and the sporting coach on a case by case basis considering tissue healing time frames and return to sport goals. Enough time should be allowed for the injured tissues to adapt to the demands of running and to allow adequate time for motor learning to occur between sessions.

Hot Topic - Can a RTR Program improve running mechanics

There is currently no consensus on whether running drills in training change running mechanics during competition. It is likely that we can influence running mechanics to some extent but that each athlete will use their own adaptive strategy during competition given individual, environmental and contextual constraints.

Summary

A return to run program is an important part of an athletes return to play process. Supervised return to run programs aim to improve an athlete’s running efficiency which both improves running performance and reduces the risk of subsequent or recurrent running related injuries.

Written By Sport Physio Cameron Dyer

Acute Shoulder Dislocation

What is a Dislocated Shoulder?

The shoulder is the most mobile joint in the body and thus susceptible to being dislocated or partially dislocated (aka subluxed). [1] The shoulder is classified as a ball and socket joint composed of three different bones: humerus, scapula and clavicle. Joints are classified as either stable joints, think knee (only moves in one direction) or a mobile joint like the shoulder or hip. Because of this mobility, stability of the joint is compromised and provided by not only the ligaments but also muscles known as the rotator cuff. These are the important dynamic restraints of the shoulder.

In the case of a shoulder dislocation, the ball (humerus) is forcefully put of out its position on its socket (glenoid labrum). This is typically associated with significant pain and an inability to use your arm until the shoulder is relocated. A shoulder subluxation is an instability event where the humerus will slide partly away from the glenoid labrum and return before a full dislocation occurs

Types of Dislocations

When the shoulder is dislocated from the joint it can occur in 3 different ways dependent upon the way that the humerus moves away from the glenoid.

·      Anterior Dislocation – most common type accounting for 95-97% of cases caused by an arm being placed in a position of abduction and external rotation like making a tackle and the shoulder displaces forwards [2]

·      Posterior Dislocation – accounts of approximately 2-4% of cases and occur with the humerus displaced towards the back of the body. This can occur with a fall on an outstretched arm or elbow [3]

·      Inferior Dislocation – the rarest type where the top of the humerus is displaced downwards, typically occurs via trauma to the shoulder.

Causes

The most common cause of shoulder dislocation is trauma through force applied to the shoulder in various angles which causes the humerus to leave the glenoid labrum. These injuries commonly in contact sports such as Rugby and AFL, Eg. When making a tackle or when contact occurs contesting for a mark. 

In addition, some people who have looser ligaments throughout their body who are able to dislocate their shoulder with relative ease. The best thing for this population is to do a targeted strengthening program to reduce the risk of dislocations occurring with repetitive shoulder movements. [4]

Management of Shoulder Dislocations

Once the shoulder is relocated, there are multiple factors that will determine which direction someone may choose to proceed with treatment. However normally non-operative rehabilitation is the first line of management. An assessment with a trained Sports Physio or Specialist Sports Doctor with the appropriate imaging can help decide the best course of management in each case.

Non-Operative Management

Conservative management is the first line of treatment in most cases of first time acute shoulder dislocation. The main goals in this type of management are

·      Pain relief – reduce localised pain and reduce swelling (Rest Ice Compression Elevation - RICE)

·      Physiotherapy - Maintain and restore muscular strength and proprioceptive feedback. Regain normal range of motion once pain has settled.

·      Rehab - Increase strength to prevent further instability episodes and withstand the forces placed on the shoulder during sport and in daily life.

·      Return to full function with prevention strategies to ideally avoid a recurrent dislocation

Surgical Management

Surgical management for this injury is common in recurrent dislocators and those returning to contact sports. These shoulder reconstructive surgeries are very successful in restoring stable anatomy allowing the athlete to their chosen sport competing at the same level. A sling will be applied post-surgery for a short period of time before the required physiotherapy. Strength rehabilitation is essential in restoring the shoulder to its pre-injury status and to prevent further injury. Rehab timeframes can last from 4-9 months depending on various factors.

Written By Sports Physiotherapist Simon Wybenga

References

1.     Dodson, CC et al. Anterior glenohumeral hoint dislocations. Orthopaedic Clinical North America, 2008. 39(4): p507-18

2.     Boone, JL et al. First time anterior shoulder dislocations: has the standard changed? British Journal of Sports Medicine, 2010. 44: p355-36

3.     Farrar NG et al. An overview of shoulder instability and its management. Open Orthopaedic Journal, 2013.  7: p338-346

4.     Cutts, S et al. Anterior shoulder dislocation. Ann R Coll Surg England, 2009. 91(1): p2-7

5.     Wang, RY et al. The recognition and treatment of first-time shoulder dislocation in active individuals. JOSPT, 2009. 39(2):p118-123

Iliotibial Band Syndrome

Introduction

Running related injuries (RRI’s) are common in long distance runners with injury incidence shown to range between 17.8 (95% CI 16.7-19.1) injuries per 1000 hours of running in novice runners and 7.7 (95% CI 6.9-8.7) injuries per 1000 hours of running in recreational runners.[1] Known risk factors for RRI’s include history of previous injury and a greater training distance per week while a gradual increase in training distance per week is a protective factor. [2]

ITB Syndrome Anatomy

Cause

Iliotibial band syndrome (ITBS) is the second most common RRI and the most common cause of lateral knee pain in runners.[3] The aetiology of ITBS is thought to be multifactorial and remains poorly understood however several biomechanical risk factors have been proposed to contribute to the condition.[4] Traditionally, ITBS was thought to be caused by friction or excessive pressure at the distal iliotibial band (ITB) as it passes over the lateral femoral epicondyle during repetitive knee flexion and extension. [5] A more recent theory suggests that impingement at this site contributes to the condition rather than purely excessive lateral pressure.[6, 7]

Biomechanical Risk Factors

Proposed biomechanical risk factors for ITBFS include increased peak hip adduction,[8] knee internal rotation,[8-10] peak trunk ipsilateral flexion,[10, 11] and peak rearfoot pronation[12] as these factors can increase abnormal lengthening of the ITB (i.e. excess strain) and contribute to compression of the ITB at the lateral femoral condyle (i.e. excess stress).[13]

Poor Biomechanincs (Right) can contribute to ITBS

Prevention and Management

Preventative measures for ITBFS should include an appropriate training plan that includes gradual increases in running distance and appropriate load management strategies including programmed rest days and de-load phases.[2]

Management

The acute management of ITBS should focus on anti-inflammatory modalities, relative rest, soft tissue release and addressing biomechanical factors known to contribute to ITBS.[13] As irritability settles running can be gradually re introduced in line with a periodised running plan. Running retraining incorporating running with an increased cadence has been shown to increase the gluteal muscle recruitment during foot strike and mid stance of the running cycle [14] and may help to decrease load at the ITB insertion in patients with ITBS.

There is debate as to whether it is possible to modify running mechanics with strengthening exercises alone however positive results have been demonstrated in studies that focus on isometric and eccentric strength of the glute muscles in running specific positions[15] and include visual feedback with cueing.[16] The hip abductor muscles are known to contribute to peak hip adduction, knee internal rotation, ipsilateral trunk flexion[17] and have been shown to be related to other lower limb RRI’s.[14] Two gluteal muscles that control frontal and transverse plane hip and pelvic motion during running include the glute max and glute med.[14] Glute max EMG is shown to be highest in the step up and single leg squat exercise while the glute med EMG is shown to be highest in the side bridge with hip abduction exercise [18] (See Pictures Below). Despite a lack of prospective research it is plausible to include gluteal strengthening 2-3 x per week in the management of ITBS given the gluteal muscles’ relationship to biomechanical factors known to be associated with the condition.

While foot and ankle orthosis have been proposed as a tool to maintain a neutral foot position and control tibial internal rotation during running[19] to date, no prospective studies have investigated the use of orthosis for patients with ITBS.

Single Leg Squat

Side Bridge with Hip Abduction

Conclusion

Based off the available evidence the best management for ITBS includes appropriate management in the acute stage to settle irritability followed by gluteal strengthening with an emphasis on isometric and eccentric frontal and transverse plane movements and physiotherapist guided running retraining.

Take Away Points

·      ITBS is the second most common RRI and the most common cause of lateral knee pain in runners.

·      ITBS is thought to be caused by either excessive lateral pressure or impingement as the ITB runs over the lateral femoral epicondyle during knee flexion and extension.

·      Gluteal weakness is proposed as a modifiable contributing factor in ITBS.

·      Gluteal strengthening should focus on isometric and eccentric exercises in running specific positions and should be carried out with appropriate cueing and visual feedback.

·      Running retraining including running with an increased cadence has been proposed to increase gluteal muscle activation during running.

Written by Cameron Dyer – Physiotherapist and Athlete Rehab Specialist

References

1.         Videbæk, S., et al., Incidence of Running-Related Injuries Per 1000 h of running in Different Types of Runners: A Systematic Review and Meta-Analysis. Sports Medicine, 2015. 45(7): p. 1017-1026.

2.         van Gent, R.N., et al., Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. British Journal of Sports Medicine, 2007. 41(8): p. 469-480.

3.         Taunton, J.E., et al., A retrospective case-control analysis of 2002 running injuries. British Journal of Sports Medicine, 2002. 36(2): p. 95.

4.         Beers, A., et al., Effects of Multi-modal Physiotherapy, Including Hip Abductor Strengthening, in Patients with Iliotibial Band Friction Syndrome. Physiotherapy Canada. Physiotherapie Canada, 2008. 60(2): p. 180-188.

5.         Orchard, J.W., et al., Biomechanics of Iliotibial Band Friction Syndrome in Runners. The American Journal of Sports Medicine, 1996. 24(3): p. 375-379.

6.         Hamill, J., et al., A prospective study of iliotibial band strain in runners. Clinical Biomechanics, 2008. 23(8): p. 1018-1025.

7.         Fairclough, J., et al., Is iliotibial band syndrome really a friction syndrome? Journal of Science and Medicine in Sport, 2007. 10(2): p. 74-76.

8.         Noehren, B., I. Davis, and J. Hamill, ASB clinical biomechanics award winner 2006 prospective study of the biomechanical factors associated with iliotibial band syndrome. Clinical biomechanics (Bristol, Avon), 2007. 22(9): p. 951.

9.         Ferber, R., et al., Competitive female runners with a history of iliotibial band syndrome demonstrate atypical hip and knee kinematics. The Journal of orthopaedic and sports physical therapy, 2010. 40(2): p. 52.

10.       Foch, E., et al., Associations between iliotibial band injury status and running biomechanics in women. Gait & Posture, 2015. 41(2): p. 706-710.

11.       Foch, E. and C.E. Milner, The influence of iliotibial band syndrome history on running biomechanics examined via principal components analysis. Journal of Biomechanics, 2014. 47(1): p. 81-86.

12.       Messier, P.S., et al., Etiology of iliotibial band friction syndrome in distance runners. Medicine & Science in Sports & Exercise, 1995. 27(7): p. 951-960.

13.       Baker, R.L. and M. Fredericson, Iliotibial Band Syndrome in Runners: Biomechanical Implications and Exercise Interventions: Biomechanical Implications and Exercise Interventions. Physical Medicine & Rehabilitation Clinics of North America, 2016. 27(1): p. 53-77.

14.       Semciw, A., R. Neate, and T. Pizzari, Running related gluteus medius function in health and injury: A systematic review with meta-analysis. Journal of Electromyography and Kinesiology, 2016. 30: p. 98-110.

15.       Fredericson, L.M., et al., Hip Abductor Weakness in Distance Runners with Iliotibial Band Syndrome. Clinical Journal of Sport Medicine, 2000. 10(3): p. 169-175.

16.       Barrios, J.A., K.M. Crossley, and I.S. Davis, Gait retraining to reduce the knee adduction moment through real-time visual feedback of dynamic knee alignment. Journal of Biomechanics, 2010. 43(11): p. 2208-2213.

17.       Mucha, M.D., et al., Hip abductor strength and lower extremity running related injury in distance runners: A systematic review. Journal of Science and Medicine in Sport, 2017. 20(4): p. 349-355.

18.       Macadam, P., J. Cronin, and B. Contreras, An examination of the gluteal muscle activity associated with dynamic hip abduction and hip external rotation exercises. A systematic review. International journal of sports physical therapy, 2015. 10(5): p. 573.

19.Aderem, J. and Q.A. Louw, Biomechanical risk factors associated with iliotibial band syndrome in runners: A systematic review Rehabilitation, physical therapy and occupational health. BMC Musculoskeletal Disorders, 2015. 16(1): p. <xocs:firstpage xmlns:xocs=""/>.

Achilles Tendon Pain And Isometrics

Tendons

Tendon injuries and pain are common amongst athletes of various sports and ages. Tendons attach muscle to bones and allow muscles to transmit force across our joints which allow us to move, walk, run and jump!

Tendons most commonly become injured when they undergo a period of loading above and beyond what they are used to. We call these injuries Tendinopathies and they have been shown to have a continuum of dysfunction ranging from reactive to degenerative, or more commonly described as acute or chronic (Cook and Purdam 2008). Due to this variability of tendinopathy injuries, management for tendon injuries can be difficult and requires accurate assessment and targeted individualised interventions.

Isometrics

Current research in patella tendons has shown isometric exercise has a place in athletes with pain as it has an analgesic effect (Rio et al 2017). The findings of these studies in patella tendons have been applied for tendons throughout the body in both professional sports and in private practice with the general population. The proposed cause of pain relief with isometrics in these studies is a reduction in pain related muscle inhibition leading to increase in strength and changes to the central nervous system which dampen pain. (Rio et al 2015)

More recently it has been proposed that this widespread adoption of isometrics may not be applicable to tendons throughout the body in areas such as the Achilles tendon, lateral epicondylalgia (tennis elbow) or hamstring tendons (Coombes et al 2016).

Achilles Tendon Anatomy

Muscles That Attach to the Achllies - Gastrocnemius Vs Soleus

There are 3 muscles that attached to the Achilles Tendon. The soleus and the gastrocs are the largest and have the most significant contribution to athletes who run, jump and change direction. The gastroc’s crosses the knee and is a more active in ankle movements when the knee is straight, and the soleus is more active when the knee is bent. The reality is that both muscles are quite different in their location and function, but they both need the be strong and work together to support the Achilles Tendon during sport.

Calf Muscle Anatomy

People with tendon injuries and tendon pain have been found to have weaker calf strength in both the injured and the corresponding limb muscles than other people without tendon pain (O’Neill 2018). Essentially if an athlete does not have the adequate strength in their muscle, their tendon will be required to take on more load. As a result we often see them fail and become painful as they attempt to cope with the excessive loading that the tendon is unaccustomed to. So STRENGTH is the key! But which type???

Other Exercise Therapy

Isotonic (Or through range strength training) strength training, which includes both concentric and eccentric components, has recently been suggested as a more appropriate way to manage tendon injuries other than the patella tendon (O’Neill et 2018).  This type of strength training needs to be heavy at around 70-80% of 8RM (repetitions maximum), and must be appropriate to the type and stage of tendon injury as detailed above. In Achilles Tendinopathies the most appropriate exercises are loaded calf raise in seated and standing positions (see pictures below). These should be progressed to single leg variations with load as symptoms and strength allows. Both of these exercises target the major calf muscles of the gastrocnemius and soleus in differing amounts.

*NOTE: These aren’t intended to be pain relieving and need to be prescribed around the athletes training appropriately.

Loaded Standing Single Leg Calf Raise

Loaded Seated Calf Raise

To Isometric Or Not

The type of strength stimulus we put through our tendon and adjoining muscles is extremely important when dealing with injury and needs to be case specific. As mentioned Isometric strength training has been successfully used for tendinopathies in certain areas of the body, and as a result adapted to other areas throughout the body.

However, they are not the only form of resistance training we should expose to an injured tendon, as strength gain’s through ROM are important and functional to the sports that many athletes play. As for the Achilles the focus should be on improving strength in the calf complex relative to the athlete’s sport. This may be a combination of loaded strength rehab and higher velocity power strength work. This ALWAYS needs to be specific to the demands of the athlete’s sport and goals.

Isometric exercises still have an important role in tendon pathology!! But they aren’t the only type of strength to take into consideration when you have any type of tendon pain.

For other general information regarding tendons and in particular patella tendons refer to our previous article published by Luke Heath on our website “Jumpers Knee: Patella Tendiopathy – Diagnosis and Management”.

For any further questions or to book an appointment contact us online or via phone.

Written By Chris Bailey - Titled Sports Physiotherapist and Rehab Specialist

References

·      Cook J, Purdam C. Is Tendon Pathology a Continuum? A Pathology Model to Explain the Clinical Presentation of Load-Induced Tendinopathy. British Journal of Sports Medicine. 2009

·      Coombes B, Tucker K, Vincenzino B. Achilles and Patella Tendinopathy Display Opposite Changes on Elastic Properties: A Shear Wave Elastograpy Study. Scandavian Journal of Medicine and Science in Sports. 2018 

·      O’Neill S, Radia J, Bird K, Rathleff M, Bandholm T, Jorgensen M, Thorborg K. Acute Sensory and Motor Response to 45-s Heavy Isometric Holds for the Plantar Flexors in Patients with Achilles Tendinopathy. Journal of Knee Surgey, Sports Tramatology and Arthroscopy. 2018

·      O’Neill S. PhysioEdge podcast Episode 82. 2018

·      O’Neill S, Watson P, Barry, S. Why are Eccentric Exercises Effective for Achilles Tendinopathy? The International Journal of Sports Physical Therapy. 2015

·      Rio E, Kidgell D, Purdam C, Gaida J, Mosely L, Pearce A, Cook J. Isometric Exercise Induces Analgesia and Reduces Inhibition in Patella Tendinopathy. British Jounal of Sports Medicine. 2015

·      Rio E, Van Ark M, Docking S, Mosley L, Kidgell D, Akker-Scheek I, Zwerver J, Cook J. Isometric Contractions are More Analgesic than Isotonic Contractions for Patella Tendon Pain: An In-Season Randomised Clinical Trail. Clinical Journal of Sports Medicine. 2017

Strength Training for Endurance Sports Performance

Strength training remains an under-utilised tool to improve performance in endurance sports despite recent evidence showing beneficial outcomes (Blagrove, Howatson, & Hayes, 2018). Concerns about slowing down, gaining muscle mass and the perceived opportunity cost of spending time performing strength training rather than doing endurance training prevent many endurance sports athletes from the benefits of strength training.

Why is this the case?

Before we discuss strength training for endurance athletes there are three primary physiological determinants of endurance sports performance that we need to acknowledge. The combination of these three factors form the primary physiological and biomechanical determinants of endurance sport outcome.

·       VO2 max – the maximal amount of oxygen that can be consumed during aerobic exercise. This can be viewed as the overall CAPACITY of the body to use oxygen to perform work.

·       Blood lactate markers – when our muscles use oxygen to create energy a waste product called lactic acid is formed. The blood lactate threshold refers to the maximal amount of oxygen that can be consumed before lactic acid accumulates and causes a reduction in work capacity.  Blood lactate markers can be viewed as the COST of muscle metabolism.

·       Economy – reflects the oxygen or energy cost of sustaining a given sub-maximal running velocity. This is a measure of how efficiently you use oxygen at submaximal levels and is determined predominantly by neuromuscular factors. Movement economy can be thought of as the overall EFFICIENCY of the body to generate energy.

A recent systematic review by Blagrove et al (2018) (Blagrove et al., 2018) reviewed 24 studies of 469 trained (>6 months) middle and long distance runners to assess the effect of strength training on the above three physiological determinants of performance. The review only included studies that had a control group of endurance only training and included strength training interventions using either heavy resistance training, explosive resistance training or plyometric training between 1 and 4 x per week.

The results of the review are included in a table 1.

Factors affecting performance

Table 1. Results from Systematic Review of Blagrove et al (2018)

The review also found that while strength training did NOT improve VO2 max or blood lactate levels, they were not negatively affected. In addition, the athletes that performed strength training achieved a higher terminal velocity in a maximal aerobic running test i.e. they improved their running velocity significantly more than matched controls that only did endurance training.

Improvements in running economy, measured as the oxygen or energy cost of running at a given speed, hold the biggest key for endurance athletes to improve their performance. Running economy was improved by three main mechanisms:

1.     Improved muscle tendon stiffness

a.     Muscle tendon stiffness refers to the bodies ability to utilise the stretch shortening cycle to generate force. Put simply, rather than the muscles having to generate all the force to propel the body forward each step, the muscle tendon unit can store elastic energy from the previous step and ‘release’ it into the following step. Think of an elite runner and how they seem to effortlessly bounce along the track verses a beginner that plods along. Who is running more efficiently?

2.     Improved neural function

a.     Strength can improve by two primary ways:

                                               i.     Greater coordination of the muscle unit

                                              ii.     Larger cross-sectional area (size) of the muscle fiber

b.     Strength training in endurance athletes works by increasing the maximum voluntary contraction and the rate of force development i.e. better coordination between the nerve signal and the muscle unit

3.     Structural changes in muscle tissue

a.     There are different types of skeletal muscle fibers that each have specific qualities. Strength training converts the large fast twitch highly fatigable (type IIX) fibers to the smaller fast twitch more efficient (type IIA) fibers.

Figure 2. Proposed mechanisms by which short term and long term endurance performance can be improved from the addition of strength training to the ongoing endurance training plan. (Aagaard & Andersen, 2010)

Interestingly, including strength training did not result in an increase in muscle mass despite participants getting significantly stronger. This is because performing a high volume of endurance training stunts the intracellular hypertrophy response normally associated with resistance training (Wilson et al., 2012) (Nader, 2006). This suggests that strength training in endurance athletes improves strength via neural changes i.e. greater coordination of muscle firing and faster rate of contraction rather than by increasing the size of the muscle.

Besides the performance benefits, strength training is also a key component of most injury prevention programs. Runners are known to have a high overall musculoskeletal running related injury (MRRI) incidence of 19.4-79.3%. (van Gent et al., 2007) The most common MRRI is medial tibial stress syndrome which is known to have several strength related risk factors i.e. low calf power and poor glute medius strength (Galbraith & Lavallee, 2009). In this way, strength training not only helps to improve performance but can help in building resilience to common running related injuries.

In summary - strength training can significantly improve running economy, running velocity and reduce time lost to common running related injuries without causing an increase in weight, muscle mass or negatively affecting VO2 max or blood lactate markers.

Which leaves me with the question…

When integrating strength training into an endurance training plan, athletes should look to work with an experienced coach that understands your injury history, training history, goals and has experience writing strength programs for running based athletes.

Many endurance sports athletes have little to no experience with strength training and for this reason the strength training program must be planned, periodised, supervised and progressively overloaded with detail and care.

For more information about strength training for endurance sports athlete’s feel free to reach out.

Written by Cameron Dyer – Physiotherapist and Athlete Rehab Specialist

References:

Aagaard, P., & Andersen, J. L. (2010). Effects of strength training on endurance capacity in top-level endurance athletes. In (Vol. 20 Suppl 2, pp. 39).

Blagrove, R., Howatson, G., & Hayes, P. (2018). Effects of Strength Training on the Physiological Determinants of Middle- and Long-Distance Running Performance: A Systematic Review. Sports Medicine, 48(5), 1117-1149. doi:10.1007/s40279-017-0835-7

Galbraith, R., & Lavallee, M. (2009). Medial tibial stress syndrome: conservative treatment options. Current Reviews in Musculoskeletal Medicine, 2(3), 127-133. doi:10.1007/s12178-009-9055-6

Nader, A. G. (2006). Concurrent Strength and Endurance Training: From Molecules to Man. Medicine & Science in Sports & Exercise, 38(11), 1965-1970. doi:10.1249/01.mss.0000233795.39282.33

van Gent, R. N., Siem, D., van Middelkoop, M., van Os, A. G., Bierma-Zeinstra, S. M. A., Koes, B. W., & Taunton, J. E. (2007). Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. British Journal of Sports Medicine, 41(8), 469-480. doi:10.1136/bjsm.2006.033548

Wilson, M. J., Marin, J. P., Rhea, R. M., Wilson, M. C. S., Loenneke, P. J., & Anderson, C. J. (2012). Concurrent Training: A Meta-Analysis Examining Interference of Aerobic and Resistance Exercises. Journal of Strength and Conditioning Research, 26(8), 2293-2307. doi:10.1519/JSC.0b013e31823a3e2d