by Sam Yim SPT
Percussion massage guns have grown in popularity within the past couple years and sponsor many pro athletes such as Patrick Mahomes and Russell Westbrook. The price point ranges from $50 for lower end models to upwards of $700 for the most expensive models. The question is, are massage guns really worth the investment? Massage gun companies state that their devices can relieve pain, increase range of motion, and decrease symptoms of soreness or stiffness. The companies also market their massage guns as ways to improve recovery time post workout and to decrease warm-up times so individuals can start their workouts faster. We’ll dive in and see if these claims are supported by the current literature.
Range of Motion and Strength
In an article published in 2020, researchers analyzed whether massage guns could actually improve range of motion as they advertise. This study took 16 adult males and split them into two groups. One group received a 10-minute warm-up on the bike with 5 minutes of treatment using a massage gun. The control group received just a 10-minute warm-up on the bike with no massage gun treatment. The treatment area of focus were the plantar flexors, which are a group of muscles in the calf that aid with pushing off the ground. The results demonstrated a 5.4 degree increase in plantar flexion with the massage gun group and no increase in range of motion in the control group.
The researchers of the above study found no difference in strength between the massage gun group and the control group. These results are supported by a study done in 2019 that delved into the effects of massage guns on vertical jump height. The researchers found that use of a massage gun did not improve physical performance measured by vertical jump height compared to general rest.
The claim to fame of massage guns is their ability to decrease soreness, pain, and to facilitate recovery. Researchers put this idea to the test and assessed whether or not massage guns were just as good or better than traditional massage therapy in preventing delayed onset muscle soreness (DOMS). The preliminary research identified that vibration therapy for 5 minutes displayed reduced DOMS equal to that of traditional massage therapy 24 hours, 48 hours, and 72 hours post exercise. Vibration therapy additionally resulted in a decreased accumulation of lactate 48 hours post exercise and reduced subjective pain levels.
There are some risks that one should consider before purchasing and using a massage gun. The main risks include causing increased soreness, bruising, and potential muscle damage. Recently there was a reported case where an individual utilized a massage gun post exercise and developed rhabdomyolysis, which is breakdown of muscle tissue. Rhabdomyolysis can be a potentially life-threatening condition if not treated appropriately. The individual in this case study did not participate in any overly strenuous exercise, just daily cycling and had no prior history of illness. The researchers attributed the cause of this case to be due to trauma from prolonged sessions of using the massage gun (greater than 10 minutes).
The current literature is not conclusive on whether or not massage guns provide the benefits that their companies say they do. Preliminary research shows that there could be some potential benefits to using massage guns such as improved range of motion, decreased subjective pain levels, and improved recovery time. However, all of the current research utilizes small sample sizes, young age groups, and minimal research is focused on the potential drawbacks of massage guns. The research also does not show the use of massage guns being any more effective compared to traditional massage techniques. Continued research with increased sample sizes are required to definitively determine the benefits, contraindications, and adverse risks associated with the use of massage guns. If you have a massage gun or are going to try one, start slowly and gradually increase the intensity and frequency of usage. If you notice abnormal aches or pain consult with your physical therapist or another medical professional.
Konrad A, Glashüttner C, Reiner MM, Bernsteiner D, Tilp M. The Acute Effects of a Percussive Massage Treatment with a Hypervolt Device on Plantar Flexor Muscles’ Range of Motion and Performance. J Sports Sci Med. 2020;19(4):690-694. Published 2020 Nov 19.
Kujala R., Davis C., Young L. (2019) The effect of handheld percussion treatment on vertical jump height. International Journal of Exercise Science: Conference Proceedings 8(7). 75.
Imtiyaz S, Veqar Z, Shareef MY. To Compare the Effect of Vibration Therapy and Massage in Prevention of Delayed Onset Muscle Soreness (DOMS). Journal of Clinical and Diagnostic Research : JCDR. 2014 Jan;8(1):133-136. DOI: 10.7860/jcdr/2014/7294.3971.
Chen J, Zhang F, Chen H, Pan H. Rhabdomyolysis After the Use of Percussion Massage Gun: A Case Report. Phys Ther. 2021;101(1):pzaa199. doi:10.1093/ptj/pzaa199
Article Review by Evan Peterson PT, DPT
The knee joint is composed of several parts. It contains bone, ligament, tendon, joint capsule, and different types of cartilage. The knee contains 2 distinct cartilages: articular and meniscus. Articular cartilage is at the ends of bones which come together to form the joint. The job of the articular cartilage is to provide a smooth surface that allows for proper gliding on the joint surfaces against one another. The meniscus cartilage on the other hand is designed to help decrease the load placed through the knee joint itself. The meniscus is horse shoe shaped and is comprised of a medial and lateral end. Because the femur and the tibia are both rounded, the meniscus is needed in order to spread out contact forces. This allows for improved shock absorption and knee stability. The menisci are composed of an anterior and a posterior which are attached to the tibia by strong roots. The roots help to provide increased knee stability and decrease amount of tibial rotation. These functions are important to protect the articular cartilage.
A meniscal tear can be either acute traumatic or degenerative. An acute traumatic tear typically occurs in the athletic population and is caused by knee twisting with a planted foot. Degenerative tears are more commonly in middle aged people both male and female. The symptoms of an acute tear are swelling, pain along the knee joint line, and locking or catching.
Root Tear Rehab Options for the Athlete
One option the athlete has is to attempt rehabilitation without surgery. Another option is for the surgeon to trim out a portion of the torn meniscus. The last option is for the surgeon to repair the meniscus. Whenever it is possible, the surgeon will prefer to repair the meniscal root of an athlete, which is based upon the desire to limit future knee arthritis. After meniscal surgery, it is recommended to attend physical therapy in order to address knee range of motion, strength, and neuromuscular knee control. The therapist can also assist in guiding the patient back to performing normal sport activities. After a meniscus root repair, there is a prolonged period of non-weightbearing and restricted range of motion to allow proper healing.
Phase I of Rehab: Surgery until 8 weeks
- Typically begins 3-5 days after surgery
- Toe touch weight bearing with brace
- Gradually unlock brace for 6 weeks; after 6 weeks no brace
- Goal to restore range of motion from 0-90 degrees, decrease leg swelling, and restore control
- Knee extension on bolster, prone hangs, quadricep sets, hamstring sets, straight leg raises, heel slides to 90 degrees
- Progression to next phase
- 8-10 weeks after surgery, pain free gait (no crutches), no swelling
Phase II of Rehab: 8 weeks post-surgery
- Goals are to improve single leg control, normalize gait, and improve functional control
- No forced knee flexion past 60 degrees, no impact activities
- Hip and core exercises, stationary bike tasks, and balance or proprioceptive drills
- To Progress
- Normal gait on all surfaces, functional tasks without unloading affected leg, and single limb stance greater than 15 seconds
Phase III of Rehab: Typically 12-16 weeks post-surgery
- Goals are good control while performing sport and work specific movements with impact
- Avoid excessive post exercise swelling or posterior knee pain with flexion
- Low velocity agility drills, closed chain progressive strengthening including unilateral tasks, begin low amplitude landing drills to prevent excess frontal plane trunk lean and reduce hip adduction during stance
Phase IV of Rehab: 20-24 weeks post-surgery
- Normal multi planar motion performed at high velocities without compensation
- Typical double leg landing mechanics
- Demonstration of adherence and understanding of HEP
- Progressive agility drills with increased velocity from the last phase
- Perform higher amplitude landing drills both bilateral and unilateral
- Reactive drills including cutting and pivoting
- Sport and work specific proprioceptive/ balance exercises
- Continue core and hip strengthening exercises.
- Progressive running program
- Returning to Sport/Work
- The patient must be cleared by orthopedic surgeon as well as the therapist/athletic trainer.
- The patient should be with a 15% deficit when performing all testing such as strength testing, hop tests, and force plate jumping.
Physical Therapy First
At Physical Therapy First, we have skilled therapists who are equipped to guide a patient through their recovery from a meniscal surgery. We take the time to examine the patient and help them to achieve their functional, recreational, and work-related goals. Please do not hesitate to reach out to us if you recently underwent or plan on having meniscal surgery.
Rehabilitation Guidelines for Meniscal Repair of Root and Complex Tears – UW health. https://www.uwhealth.org/files/uwhealth/docs/pdf/Meniscus_Root_Rehab_final.pdf. Accessed February 10, 2022.
Reviewed by Evan Peterson PT, DPT
Mobility over the last several years has been a source of topic when discussing general health and wellness. Many people believe the more mobile a joint is the better off it will be. There are varying degrees to which a joint may be mobile. A hypomobile joint is one in which the bones do not glide or roll as well as one would expect. The opposite is for a joint to be hypermobile. Joint hypermobility is the excess to which a joint has the ability to go through its range. Increased joint play is not always bad, at times it can be advantageous. However, increased mobility may lead to increased risk for injury or be a sign of systemic disease. These diseases are known as Heritable Disorders of Connective Tissue (HDCT). The 2 most common of them is Ehler’s Danlos Syndrome (hEDS) and Hypermobility Spectrum Disorder (HSD).
Where do we see hypermobility?
A variety of factors can influence who gets hypermobility, including age, gender, muscle tone, joint shape, injury, and systemic disease. More often than not, children are more mobile and as they age they become less mobile. Due to the aging affects on joint mobility, scoring tools must be adjusted to determine the severity. Factors such as injury or training can play a factor in the development in mono-articular joint hypermobility. For example, the article notes swimmers tend to have knee extension hypermobility and gymnasts seem to have greater hip hypermobility.
To identify hypermobility, it is important to examine both active a passive range of motion (ROM) in joints. Several screening tools have also been developed to look for generalized hypermobility. The most commonly utilized is the Beighton scale which is a 9-item list. Scores of 6 or more in 5-year olds to skeletal maturity, 5 or more in adults to 50 years of age, and 4 or more when older than 50, is positive. Along with the screening tool, a 5-part questionnaire is typically attached. This is the 5-part hypermobility questionnaire which asks questions such as “Do you consider yourself double jointed” and “Can you now (or could you ever) bend your thumb to touch your forearms?”. Despite this screening tool, it does not completely rule out generalized or other forms of hypermobility. Specifically, the temporomandibular, shoulder, hip, cervical, and ankle, joints should be paid close attention. Other recommended screening tools are the Upper Limb Hypermobility Assessment Tool (ULHAT) and the Lower Limb Assessment Score (LLAS). The LLAS is the only one of the two which has been validated for the pediatric and adult; whereas, the ULHAT has been validated for adults.
Diagnosing Hypermobility Disorders
The most common diagnosis of hypermobility in the past was Joint Hypermobility Disorder; however, most recently hypermobile Ehler’s Danlos Syndrome (hEDS) and Joint hypermobility (JH) are thought of as a spectrum ranging from asymptomatic JH to hEDS. Filling the middle of this spectrum is HSD. The importance of recognizing HSD is to understand that it may appear in a variety of different ways: localized, peripheralized, generalized, or historic. Historic refers to someone who had joint hypermobility in the past but due to an injury lost their ability to demonstrate increased mobility.
The severity of both HSD and hEDS present across a spectrum and can be complex or present with minimal symptoms. Symptoms typically are musculoskeletal pain, fatigue, dysautonomia, gastrointestinal, urogenital, and cognitive symptoms. Central sensitization has also been found to be a common symptom. Other common findings alongside hEDS and HSD are postural tachycardic syndrome (POTS) and Mast Cell Activation Syndrome. The link between hypermobility and these disorders are not fully understand at this time.
Dysfunction in hEDS or HSD typically are related to pain, fatigue, or psychosocial stress. In children it is common to also have developmental coordination disorder which can persist into adulthood. A key aspect of hEDS is that it is a first-degree family diagnosis which can be picked up in the subjective. Due to systemic symptoms, therapist may need to refer out to other specialists for more well-rounded care. When performing physical aspect of assessment pay close attention to end ranges of motion due to increased risk of aggravating pain. It is also recommended to perform tests such as the LLAS or ULHAT. The author suggests tests, such as the navicular drop test, are indicated to further assess mobility of foot and ankle joints. Therapist should pay close attention to neuromuscular control, balance, and proprioception as these have all been shown to be associated with hypermobility disorders. If finding symptoms of dizziness, chest pain or syncope, therapist should take blood pressure and heart rate. Greater than a 30-beat increase in heart rate upon standing in adults is suggestive of POTS; greater than 40 beats in children. When examining children, it is important to address quality of movements as well which may not be observed when utilizing the BOT-2 or Movement ABC.
Evaluation, Diagnosis, Management
For hEDS to be diagnosed 3 criteria must be met. They must have generalized joint hypermobility, systemic manifestations of a connective tissue disorder, and the exclusion of other reasons for the current symptoms. After diagnosis is made, the therapist must address the severity of the disorder in order to establish if a multi-disciplinary approach is required. One of the most important interventions is education. Patients who understand their triggers for exacerbation can more effectively reduce symptoms when flare ups occur. It is also important to understand various strategies to protect joints as well as manage subluxations/dislocations. Other suggestions are adding compression clothing in order to enhance proprioception. Exercise is the mainstay in management as it has been shown to decrease spinal pain, joint pain, and improved neuromuscular control of movements. Often patients with hEDS respond well to strengthening programs but require gradual progressions in order not to aggravate muscle and tendon. In patients with POTS, it is also important to understand their decreased tolerance for exercise and increased fatigue following exercise. Patient’s should be educated on ways to mitigate symptoms such as fist clenching. It is recommended to begin with recumbent exercises and lower extremity tasks to promote venous return.
As is evident by the above presented information patient with hypermobility disorders would benefit greatly from skilled intervention focusing on a variety of factors. It is important to address each of the impairments through exercise and education. It is also important to recognize when a person requires a multi-disciplinary approach for overall improvement in symptom management.
Physical Therapy First
We here at Physical Therapy First are trained to examine a variety of patients who presents with symptoms related to hypermobility. At PTF, therapists are experienced utilizing scales, such as the Beighton scale, and work with patients to create exercise routines appropriate for the individual. We understand the many factors that may present themselves in a person with hEDS and can tailor strategies to decrease pain and improve functionality. If you are someone who was diagnosed with hEDS or feel that you are hypermobile and have increased pain, please do not hesitate to reach out to the therapists at Physical Therapy First.
Simmonds, J. V. (2022). Masterclass: Hypermobility and hypermobility related disorders. Musculoskeletal Science and Practice, 57, 102465. https://doi.org/10.1016/j.msksp.2021.102465
Article reviewed by Evan Peterson PT, DPT
Foot pain is a common injury experienced across the population in both the athletic and non-athletic population alike. There are many different causes for foot pain, but one in particular is often misdiagnosed or missed. Cuboid syndrome is one cause of lateral foot pain which is thought to arise from a change in the arthrokinematics of the calcaneocuboid joint. The author of this article states this condition may be brought on insidiously or after a traumatic event.
The Cuboid and It’s Mechanics
The cuboid is surrounded by a variety of other foot bones on the lateral side of the foot. Its borders are the navicular, the calcaneus, the 4th and 5th metatarsals, and the lateral cuneiform. The cuboid is part of the midtarsal portion of the foot and moves in tandem with the navicular. Though it has a variety of motions, the calcaneocuboid joint typically rotates medially or laterally (inversion or eversion). Due to the congruence of articular surfaces, the cuboid is relatively stable but it also has the support of ligaments as well as a fibroadipose labra between the calcaneocuboid joint and cuboid-metatarsal joints. Another stabilizing feature is the peroneus longus tendon wrapping underneath the cuboid. The cuboid acts as a pulley system for the peroneal tendon to allow for efficient eversion during the late stance phase of gait to propel the body forward. The mid tarsal joint plays a large role in allowing the foot to be both a mobile adaptor and a rigid lever for push off. When the foot transitions its weight from lateral to medial, it creates the windlass effect giving the foot enough energy to push off effectively.
What Causes Cuboid Syndrome?
Although a distinct reason for the cause of cuboid syndrome is uncertain at this time, several pathologies have been suggested as culprits. Causes proposed are excessive pronation, overuse, and inversion ankle sprains. The actual mechanical movement of the cuboid is isolated eversion while the calcaneus is in an inverted state. The unwanted cuboid eversion may be caused by improper peroneus longus muscle firing causing an eversion moment on the cuboid. In turn, causing incongruence between the calcaneus and the cuboid resulting in pain.
There are a multitude of factors that could predispose someone to cuboid syndrome such as ill-fitting shoes, midtarsal instability, and being overweight. A study showed 80% of patients with excess pronation had cuboid syndrome due to the increased moment arm of the peroneus longus. Because the calcaneocuboid joint has a labrum, it may become impinged and restrict motion.
The prevalence of cuboid syndrome is not fully understood but it appears to be most common in ballet dancers with foot/ankle injuries or those with plantarflexion/inversion sprains.
What to Look For
Pain is often broadly felt along the lateral aspect of the foot. There may also be bruising, redness, and in some cases a prominence may be felt along the plantar surface of the foot. Patient may be tender to palpate along the peroneals, the cuboid groove, or the extensor digitorum brevis muscle. The patient may also have pain with resisted eversion as well as painful or decreased push off during gait. Although there is no gold standard for cuboid syndrome testing, the author suggests two procedures to rule in the possibility of cuboid syndrome. Either the midtarsal adduction test or the midtarsal supination test. The adduction test stabilizes the calcaneus while the mid tarsal joint is distracted medially and compressed laterally. The supination test adds compression into inversion and plantarflexion. Pain may also be elicited with dorsal or plantar cuboid movement with surrounding joints stable. The therapist must rule out fracture or dislocation of the cuboid, calcaneus, 4th and 5th metatarsals, plantar fasciitis, sinus tarsi syndrome, and several others.
Treatment of Cuboid Syndrome
It is recommended to perform manipulations upon initial presentation of cuboid syndrome. The two techniques most commonly used are the cuboid whip and the cuboid squeeze. The cuboid whip is performed with the patient in prone and the patient’s foot resting in neutral. The therapist then will “whip” the foot into plantarflexion and inversion while thrusting thumbs into cuboid. The cuboid squeeze is performed when the therapist stretches foot into maximal plantarflexion and maximal toe flexion. The therapist will then push the cuboid dorsal. Manipulation should only be performed when bruising subsides or the patient has no other contraindications for manipulation. Following manipulation, if successful, the therapist can implement taping techniques, lateral wedge, and foot intrinsic strengthening.
Physical Therapy First
If you are someone who recently had an ankle sprain or have been experiencing lateral foot pain, reach out to Physical Therapy First where you will be examined by a physical therapist trained in the techniques to pick up on and address cuboid syndrome.
Durall, C. J. (2011). Examination and treatment of Cuboid syndrome. Sports Health: A Multidisciplinary Approach, 3(6), 514–519. https://doi.org/10.1177/1941738111405965
by Bridget Collier PT, DPT
The study, “Comparison of 3 Preventative Methods to Reduce the Recurrence of Ankle Inversion Sprains in Male Soccer Players” looks at 3 interventions and a control group to determine which is the most effective in preventing recurring ankle sprains.
Ankle inversion sprains are the most common injury among soccer players. This type of injury occurs when the foot is pointed and turns in. Multiple studies have found that once an individual sprains their ankle, they have an increased chance of reinjuring the same ankle.
There are three interventions that have been proven to help prevent re-current ankle sprains in previous studies; proprioceptive training, strength training, and ankle orthoses. Proprioception refers to the awareness of one’s self movement and body position and training typically includes balance activities on varying surfaces. In terms of strength training for the ankle, multiple studies have determined that strengthening the ankle evertors will help to prevent re-current ankle sprains. Ankle orthoses (ankle braces) are a commonly used device that individuals wear to prevent ankle sprains and research has supported that these can help protect the ankle during impact.
This study separated 80 male soccer players participating in a men’s league with a history of an inversion ankle sprain in the previous season with no prior history of LE injuries into 4 groups. The groups consisted of proprioceptive training, strength training of the evertors, orthoses group (using the Aircast Inc Sport Stirrup orthosis), and a control group (no treatment intervention completed). The athletes were followed for one soccer season where each group participated in about 120 games and practices combined.
This study found that one individual in the proprioceptive training group, four individuals in the strength training group, two individuals in the orthosis group and eight individuals in the control group had a re-current ankle sprains during the soccer season. Statistically, there was a significant lower incidence of ankle sprains in athletes of the proprioceptive training group compared to the control group. However, there were no statistically significant differences between either the strength training group or the orthosis group compared to the control group.
Overall, the study found that proprioceptive training is an effective intervention to reduce risk of ankle sprains when compared to no intervention in male soccer players who have suffered a prior ankle sprain. Although this study did not find significant differences between the strengthening and orthotic group compared to the control group, there is other clinical evidence that indicates that these interventions have been proven effective. This study was relatively small with a select population, so results may have been statistically significant if the study was broadened.
For more information regarding this topic or the research presented, please see the article referenced below. If you have an ankle sprain or re-current ankle sprains, the physical therapists here at Physical Therapy First will examine you and develop an individualized rehabilitation plan to help improve your symptoms. Proprioceptive and strength training will likely be incorporated into your unique program. Give us a call or visit the website to schedule an appointment!
Mohammadi, Farshid. (2007). Comparison of 3 Preventive Methods to Reduce the Recurrence of Ankle Inversion Sprains in Male Soccer Players. The American journal of sports medicine. 35. 922-6. 10.1177/0363546507299259.
Article Review by Evan Peterson PT, DPT
Over the years, there has been much discussion regarding building “core” muscle and stability. When the term “core” is used, generally the public immediately is drawn to the abdominal and trunk musculature. In this article by McKeon et al (2014), the writers discuss the importance of a different core system. They address the need for further attention to the intrinsic portion of the foot alongside the extrinsic muscle system for improved mechanics and function.
Throughout our normal gait pattern, the human foot has to go through many adjustments and adaptations to allow for the most efficient gait possible. Each phase of the gait cycle requires the different structures to stiffen or become mobile for proper energy storage and release. If the 4 intrinsic layers of the foot do not operate appropriately it may lead to unwanted deformation of the arch, which in turn, leads to a variety of problems such as plantar fasciitis, posterior tibial tendon dysfunction, medial tibial stress syndrome, and chronic lower leg pain.
The authors discuss the origin of the human foot and its development of arches defined by long and strong ligaments, an adducted great toe, shortened lateral toes, and compaction of the mid tarsal region to help prevent collapse. Apes unlike humans also lack the pronounced Achilles tendon and plantar aponeurosis designed for storing and releasing energy required for running. Humans, unlike quadruped runners, also have the additional intrinsic foot muscle system. Quadruped runners rely almost solely on passive stability from ligaments.
Due to the above-mentioned facts, McKeon et al, suggest the idea of the “foot core system” which working together provides stability and flexibility to accommodate varying surfaces and loads. The system consists of 3 different subsystems: Passive, Active, and Neural. The passive system consists of the bones of the foot which create a half dome, the plantar fascia, and ligaments of the foot. The active subsystem of the foot consists of both intrinsic and extrinsic foot musculature. The extrinsic muscles start in the lower leg and cross the ankle joint; whereas, the intrinsic are all located below the ankle joint. The intrinsics and extrinsics along with the passive system work synergistically to allow for proper foot function. The neural system accounts for the proprioceptive aspects of the plantar fascia, ligaments, joint capsules, muscles and tendons. It is proposed that the foot intrinsics play a key role in detecting quick stretches allowing for correction in foot dome posture.
Despite the evident importance of the core muscle system, currently there is no gold standard for measurement of the foot intrinsics. Most testing looks at flexion strength which does not completely isolate the intrinsic system and also does not test the person’s ability to maintain an arch. The authors suggest an intrinsic foot muscle test, which looks at the ability to maintain and the medial longitudinal arch while in single limb stance after the therapist sets the foot in subtalar neutral. The goal is to maintain the arch without excessive global muscle involvement.
To address any deficits found, it is suggested to utilize the “short foot” exercise as opposed to toe flexion exercises like the towel crunch in order to eliminate flexor hallicus longus and digitorum longus involvement. McKeon et al relate this to the idea of the abdominal draw in maneuver used for lumbopelvic core stability. It is necessary to build a strong base to allow for the other moving parts to perform correctly. Several studies, as mentioned in this article, have shown the short foot exercise to improve balance and self-reported function in those with chronic ankle instability.
Due to the importance of our foot’s core, the authors believe barefoot/minimal footwear is ideal for training the intrinsic foot musculature. Studies have shown increase in foot core muscle size while wearing barefoot shoes as well as have demonstrated improvements in balance and postural stability. The authors do not suggest this method for those with altered sensation in their feet.
The authors believe, at first adding external support to the foot in an acute injury is acceptable; however, the support should be removed as soon as possible to allow for strengthening of the foot core.
Here at Physical Therapy First, you can work with a physical therapist 1 on 1 for an examination and be instructed in the proper way to address your foot’s core.
McKeon, P. O., Hertel, J., Bramble, D., & Davis, I. (2014). The foot core system: A new paradigm for understanding intrinsic foot muscle function. British Journal of Sports Medicine, 49(5), 290–290. https://doi.org/10.1136/bjsports-2013-092690