Description

Cervical Radiculopathy (CR) is an objective loss of sensory and/or motor function as a result of conduction block in axons of a spinal nerve or its roots (IASP, 2011) due to compression or irritation of the cervical spinal nerve root (Woods \& Hilibrand, 2015). Etiology is atributed to cervical foraminal compression in 70-75 % of cases due to anterior and posterior degenerative changes of the zygapophyseal joints, cervical spondylosis and reduction in disc height (Carette \& Fehlings, 2005; Radhakrishnan et al.,1994). The most common clinical manifestations of CR include sensory impairments (e.g. paresthesias), motor abnormalities (e.g. muscle weakness) and neck pain radiating to the arm (Katsuura et al., 2019; Marco et al., 2022; Yousif et al., 2025).

It is a common diagnosis, incidence of which ranged between 0.832 - 1.79 per 1,000 person, and prevalence values ranged from 1.21 - 5.8 per 1,000 according to the latest epidemiological studies (Mansfield et al., 2020).

The incidence of neck pain was found to be high in college students: 48%-78% (Hanvold et al., 2014; Crawford et al., 2018). What is more, the annual growth rate of cervical spondylosis in college students was twice that of the 50-year-old participants (Zhao et al., 2020). A high incidence of neck pain among college students was associated with a heavy academic workload and the pressure of examinations, which may lead to the deformation of the neck and shoulders, as well as soft tissue damage (Algarni et al., 2017).

In the meta-analysis by Gao et al. (2023), the effect of college grade differences on neck pain was analyzed in 2287 college students. The results showed that a higher probability and frequency of neck pain occurred at senior grade level. As can be seen from the review of existing literature, based on the incidence of neck pain, the potential of developing cervical radiculopathy is increasing at a younger age than was previously shown by Radhakrishnan et al. (1994), in which the peak age was 50 to 54 years. If left untreated, CR could lead to future disability and persistent functional impairments due to neural inflammation and edema, hypoxia and ischemia of structures (Carette \& Fehlings, 2005; Kim et al., 2017).

However, despite the severity of the condition and the rapid incidence growth rate, there is still a lack of evidence in the area of conservative treatment, i.e. physiotherapy options. For example, Kroeling et al. (2013) showed that Electrical Muscle Stimulation (EMS) had no significant impact on pain relief, disability and patient satisfaction when used as an adjunct to cervical mobilization and manipulation, at post treatment, short-term and intermediate-term follow-up. Moreover, exercise treatment (ET) also consists of various interventions and is typically combined with drugs and other treatments, which make it difficult to determine the effects of a single intervention (Liang et al., 2013).

Nevertheless, results of more recent studies, are favoring application of EMS on various muscle groups, for example Kemmler et al. (2021) it was stated that EMS has significant effect on muscle strength of quadriceps and trunk extensors, similar randomized controlled trial by Lee et al. (2023) also observed significant effect of EMS on upper extremity strength. Moreover, Jang et al. (2014) showed that neuromuscular electrical stimulation (NMES) induced a decrease of cortical activation during execution of hand movements, which indicates that application of NMES can increase the efficiency of the cerebral cortex during execution of motor tasks.

One should also consider that in the recent systematic review by Gross et al. (2015) solitary ET directed on strengthening deep cervical flexors, scapulo - thoracic and upper extremity muscles had beneficial effect on pain and function at immediate post treatment and up to long-term follow-up. Moreover, strong evidence was found for effectiveness of deep cervical flexors (DCF) training on neuromuscular coordination of the neck (Blomgren et al., 2018), because it reduces the overactivation of the superficial muscles (Brage et al., 2015) and improves the activation pattern of the cervical muscles (Jull et al., 2009).

It is also worth mentioning that, compared with the healthy adults, the individuals with CR have significantly smaller anterior displacements of the centers of mass and pressure (Lin et al., 2021), reduced muscle activity of the upper trapezius (Lin et al., 2021), sternocleidomastoid and splenius capitis muscles in response to all postural perturbations (Boudreau \& Falla, 2014). Those findings are indicative of altered neural control of the neck musculature (Boudreau \& Falla, 2014), leaving the cervical spine vulnerable to reactive forces (Falla et al., 2004).

Thus, physical therapy options for conservative management of CR should mainly focus on improving muscle function and neuromuscular control of the neck.

Given the promising results of EMS and ET, it is worth to investigate both in terms of neck muscle function. Thus, this research will try to do that.

Looking at the existing literature, training based on electrical muscle stimulation and voluntary muscle contraction has positive effects on muscle strength of various muscle groups, when applied in superimposition due to facilitation of additional muscle fibers recruitment (Koutedakis et al., 1995; Pailard et al., 2005; Barsi et al., 2008).

However, superimposition of electrical stimulation on exercise was not assessed in the context of CR patients, who present with incomplete central activation levels and could favor from this kind of treatment, in terms of improving motor control. Additionally, according to Kisner et al. (2018) restoring muscle balance in cervico - scapular region, adds to the proper neutral alignment of the cervical vertebrae, leading to increased intervertebral foraminal area, decreased nerve root compression and relieve of cervical radiculopathy symptoms.

Thus, the proposed study is aimed to investigate the effects of exercise therapy with electrical muscle stimulation and just exercise on cervical muscle function. Secondly, compare the effects of both therapy options. Lastly, see if improvement of neck muscle function would have and impact on cervical radiculopathy symptoms, in terms of pain and motor deficits.