Efficacy of muscles training versus stretching in plantar fascitis management-A comparative study

The feet are
essential support to the body in weight transmission, balance, posture
maintenance and gait. They are responsible for the autonomy, independence and
wellbeing of the individual. Foot posture and function are closely linked to
the development of specific foot disorders. Currently, there is an increase
in the prevalence of foot pathologies, ranging between 61 and 79%, which is
why they constitute an important public health problem**.1,2**

Feet is the complex anatomical structure, understanding the foot and ankle conditions is important, as these conditions can significantly impact patients quality of life and mobility.3 Foot impairments, such as pain and weakness, are associated with functional limitations and disability, particularly in older adults.4

Heel painis a common presenting symptom and has an extensive differential diagnosis such as plantar heel pain includes plantar fasciitis/fasciosis, Heel spur, Calcaneal stress fracture. Posteriorly includes Achilles tendinopathy, Retrocalcaneal bursitis, Haglaund deformity. Midfoot(medial) includes posterior tibialis tendinopathy, Tarsal tunnel syndrome, Flexor digitorum longus tendinopathy, Flexor hallucis longus tendinopathy. Midfoot(lateral) includes Peroneal tendinopathy, Sinus tarsi syndrome**.5**  Plantar fasciitis (PF) is recognized as the most common cause of heel pain, contributing significantly to foot pain cases.6

PF is also known as plantar fasciopathy, is a painful heel condition caused by inflammation of the plantar fascia aponeurosis at its origin on the calcaneous7 and normally occurs during the first few steps in the morning or after a prolonged non-weight bearing activity. The condition presents  as  sharp  pain  in  the heel that extends  from the medial border of the plantar fascia at the medial  tuberosity  of  the  calcaneus**.8** The condition is associated with degeneration of the plantar fascia, often exacerbated by factors such as obesity, over-pronation of the foot, overuse injuries9 and by repetitive trauma, excessive stretching, which can result in inflammation and tears in the plantar fascia.10

PF is prevalent in the United States, with millions experiencing heel pain annually. PF occurs in about 10% of the general population, with 83% of these patients being active working adults between 25 and 65 years. The peak incidence is among the general population of 40 to 60 years.  11% to 15% of all foot symptoms requiring professional medical care. This condition accounts for about 10% of runner-related injuries. A higher prevalence of PF was observed in women compared to men.11

Risk factors for developing PF can be divided into anatomical, biomechanical, and environmental. Anatomical factor includes Pes planus, Pes cavus, Obesity, Fat pad atrophy, Shortened Achilles tendon. Biomechanical factors are Equinus, weak plantar flexor muscles, weak intrinsic muscles of foot, Excessive subtalar joint pronation, limited ankle dorsiflexion   and Environmental risk factor are trauma, hard surfaces, walking barefoot etc12.

Diagnosis of PF can be made through the patient history, clinical symptoms, foot questionnaires, and objective assessments such as pain level, palpation, muscle tightness, joint range of motion, or muscle strength. In addition, diagnostic imaging may be used to exclude other causes of pain such as heel spurs or tissue inflammation.13 Ultrasonography may be diagnostically useful but routinely it is not used. Here the thickness of the plantar fascia will be increased.14

Early recognition and management of PF leads to short course of treatment and greater chance of success with conservative therapies. Generally, these patients start with non-surgical or conservative treatment. If this treatment cannot improve the symptoms after 6–12 months, surgical treatment will be considered.13  Numerous interventions have been described for treatment of  PF, which include: Oral analgesia,  non-steroidal anti-inflammatory drugs (NSAIDS), rest, heat, ice pack, heel pads, magnetic insole, night splints, walking cast, steroid injection, platelet-rich plasma injection, and surgery.15

The physiotherapy treatment techniques for PF include passive joint manipulation of the ankle and foot; myofascial manuevers of the gastrocnemius, soleus muscles, and plantar fascia; neural mobilization of the tibial nerve, stretching of plantar fascia and triceps surae; strengthening of hip abductors andexternal rotators. Electrotherapy modalities like cryotherapy, ultrasound, laser and kinesio taping are found to be effective in reducing plantar heel pain.16

Ultrasound (US) is the Electrotherapy modality used in treating pain in PF. US is a high frequency sound wave with an affinity for tendons and ligaments (highly organized, without high water content). US enhances to increase chemical activity in tissues, increase cell membrane permeability, deform molecular structures, and alter diffusion and protein synthesis rates, all potentially affecting the speed of tissue repair.17 A study conducted by Hana Hronkova on PF in which group received US for PF showed significant reduction in pain18,19. Another study conducted by Nipapron Konjen MD et al in 2015, concluded that in chronic PF treatment both rESWT and US groups found to be effective in reducing pain and increasing mobility.36

 Even though PF has several risk factors, an abnormal biomechanical structure is considered to play an important role. Abnormalities include tightness in the Achilles tendon and plantar fascia and reduced foot and ankle muscle strength.21 Patients with  PF often also have myofascial restrictions and muscle stiffness or tightness in the gastro-soleus complex and plantar fascia.22,23 Among several conservative treatments, plantar fascia–specific and gastrocnemius/soleus stretching have shown to have moderate treatment effects which provide short-term (1 week to 4 months) pain relief for individu­als with heel pain/ PF. They are often used in the treatment programs for the patients with PF.24,25 In 2006, Digiovanni et al.26 reported that specific stretches of the plantar fascia for 8 weeks had the long-term benefit of reducing pain and function limitations, with high rate of patient satisfaction. A more recent sys­tematic review by Sweeting and colleagues concluded that the main pain-relieving benefits of stretching appear to occur within the first 2 weeks to 4 months, but could not support one method of stretching over another as being more effec­tive for reducing pain or improving function27.

On the other hand, strengthening exercises focus on enhancing the strength of the foot and lower leg muscles, which can help support the arch of the foot and reduce strain on the plantar fascia (Barredo et al., 2007).28

Reduced strength of the plantar flexors, toe flexors and abductor hallucis muscles as well as a reduction in muscle volume in the forefoot are reported to contribute to  PF.35 In 2015, Sullivan et al29 identified musculoskeletal factors in patients with PF compared to normal healthy people, and they found weakness in various muscles such as ankle evertors (peroneus brevis and longus) and toe flexors (flexor hallucis longus and brevis, flexor digitorum longus and brevis).29 In addition, weakness of the tibialis posterior muscle was also reported in previous studies.25,30

Weakness of the intrinsic and extrinsic muscles of the foot may result in the recurrent symptoms of PF due to improper functioning of the muscle and joint positioning during walking.20,25,29  Results of the univariate analysis showed that the following factors predicted a higher rate of  PF: being 40 to 55 years old; being 56 to 65 years old; having weakness of the gastrocnemius, soleus, and intrinsic foot muscles31. Weakness and tightness of the gastrocnemius soleus and the intrinsic foot muscles were found in 0.9% of the participants. Similar findings were reported in the study conducted by Huerta et al., in which tightness of the gastrocnemius muscle was found to be linked with PF in most of the participants31. According to a 2014 study by Rathleff et al., daily heel-raising activities are more helpful than plantar-specific stretching after three months. At 1, 2, 6, or 12 months following this intervention, however, these exercises did not demonstrate any difference in foot function13.

Research has shown that a combination of stretching and strengthening exercises can be effective in managing  PF. Studies have compared different physiotherapy methods, including calf stretching and plantar fascia-specific stretching**,** and have found positive outcomes in terms of pain reduction and improved function(Ersen et al., 2017)

The closed kinetic chain theory suggests that proximal core hip strength is needed for control of distal segments to prevent injury. If one joint of the lower extremity is not functioning properly, injuries can be manifested in other joints or structures, particularly those that are distal to the affected joint.  So hip muscles weakness may play a role in knee and ankle overuse injuries. Studies identifying various diagnoses and treatment findings in injured runners experiencing anterior knee pain,  Achilles tendinosis,  PF and stress fractures have focused examination findings and biomechanical risk factors directly on or distal to the site of pain but have not included proximal risk factors such as hip weakness. Recent studies have reported that foot postures such as apparent low-arch foot (pronated) and high-arch foot (supinated) were associated with weakness of the hip abductor muscles, since the hip muscles play an important role in lower limb biomechanics. Increased compensatory mechanisms of the ankle joint caused by weakness of the hip abductor muscles may have caused the intractable heel pain. Weakness of the hip abductor muscles during walking may result in plantar flexion muscle overuse, which can increase the load on the plantar fascia.33,34

The exercise regimens mentioned earlier play a role in promoting PF recovery by enhancing muscle strength and alleviating muscle tightness. However, due to a scarcity of comparative studies evaluating the efficacy of muscles training versus stretching exercises, it remains unclear which type of exercise yields greater improvement in PF symptoms. Therefore, this study aimed to investigate the effects of muscles training and stretching exercise programs combined with a physical therapy intervention on pain intensity, disability and activity restriction in patients with PF.