Cerebral palsy (CP), a condition caused by damage to the brain’s structure and function, is the most common and severe movement disorder in children, with a prevalence of 1.6 per 1000 live births [1,2]. The brain injury itself is permanent and nonprogressive, but its consequences change over time [3]. CP is an umbrella term for a group of movement and functional disorders that encompass a highly heterogeneous population with varying levels of motor ability and functional capacity [3]. Therefore, CP is classified into subtypes based on clinical localization, predominant movement patterns, and functional capacity. The most common subtype is spastic CP, which accounts for approximately 80% of all CP cases [4].

For the classification of function in children with CP aged 0 to 18 years, clinicians and researchers usually use the Gross Motor Function Classification Scale (GMFCS) and Gross Motor Function Classification System—Expanded and Revised (GMFCS-ER). The GMFCS describes gross motor function, limitations of everyday activities, functional performance, and the use of assistive devices [5]. The classification is rated from I to V, with level I indicating minimal impairment of gross motor function [5].

CP resulting from upper motor neuron damage causes a sensorimotor disorder characterized by a velocity-dependent increase in muscle tone and stretch reflex activity [6]. Furthermore, it can show nonvelocity-dependent involuntary background activation. Nonneural factors (specifically, altered muscle mechanical properties) are also frequently present and limit joint range of motion (ROM) [7].

Although both neural and nonneural factors contribute to the joint hyper-resistance and movement difficulties observed in children with CP [8], nonneural factors may also play key roles in maintaining long-term functional ability [9,10]. This is because alterations in muscle mechanical properties (eg, increased stiffness) significantly impair a muscle’s ability to lengthen. Consequently, although the early brain injury in CP is nonprogressive, the associated musculoskeletal problems tend to worsen over time [11,12]. Impaired muscle lengthening capacity, especially during growth spurts, can rapidly reduce joint ROM, potentially leading to permanent muscle shortening. This condition, known as contracture, is characterized by abnormally stretched sarcomeres, a reduced number of sarcomeres in series, and alterations in collagen and the extracellular matrix (ECM) [13]. Children with CP can, as they grow, develop a permanent shortening of their musculotendinous units [14]. Contractures have clinically significant consequences, as they are associated with joint and bone deformities, pain, and loss of mobility [15].

The combination of muscle weakness, reduced ROM, contractures, and joint hyper-resistance often leads to altered gait patterns in children with CP [7,16]. These changes can result in a decrease in, or even the loss of, walking ability, while also causing difficulties in standing, balance, mobility, and overall functional capacity [16]. Walking ability in individuals with CP varies significantly depending on the severity of the motor deficits [17].

A common movement deviation in CP is crouch gait, which arises from short and spastic hamstring muscles. It is characterized by excessive knee and hip flexion and is often accompanied by in-toeing or out-toeing [18]. Another frequently seen deviation is toe-walking, which is associated with ankle equinus (increased ankle plantarflexion) resulting from short and spastic ankle plantar flexors [19]. These and other alterations in gait patterns can severely impair walking efficiency in children with CP [18], leading to increased energy consumption and fatigue during walking compared to healthy peers [20]. Thus, one of the main goals of rehabilitation for children and youth with GMFCS levels I to III is to improve walking ability, as enhanced walking can support the development of other motor functions while also promoting greater participation in daily life activities [17].

Both active and passive stretching have traditionally been used in rehabilitation to prevent muscle tightness and contractures and to improve movement patterns in children with CP [21,22]. The effects of stretching have been well studied; acute and long-term results show an acute increase in ROM of around 10° [22,23]. However, Harvey et al [24] found that stretching does not have a clinical impact on ROM. Kalkman et al [22] found that the muscles and tendons in children with CP do not exhibit acute changes following a series of stretching sessions, suggesting that they do not contribute to the observed increase in ROM. Instead, there was an increase in the maximal ankle joint torque tolerated by the participants [25].

Various factors, including alterations in muscle length [26], tendon length [22,27], and cross-sectional area [28], as well as changes in connective tissue properties [27], may contribute to muscle stiffness and reduced flexibility in CP. Furthermore, it has been suggested that the tendons may be longer and more compliant in children with CP than in their typically developing peers.

Indeed, in ankle plantar flexors, stretching exercises have been shown to primarily elongate the more compliant Achilles tendon rather than the muscle itself [29]. In children with CP, an increased amount of connective tissue within the muscle is associated with a reduced ability of the muscle to extend [23]. The lengthening of the muscle belly depends on the properties of both the muscle fascicles and the surrounding connective tissues—specifically the perimysium and endomysium [22]. As a result, fascial tissue may be the primary limiting factor in muscle elongation and should, therefore, be the main target during static stretching [30,31]. Although acute increases in ROM have been observed following stretching, there is no clear evidence supporting its effectiveness in preventing contractures [24]. Consequently, treatment strategies that more effectively target muscle connective tissues, such as fascia, could potentially lead to better outcomes in increasing ROM.

The role of fascial treatments in the rehabilitation of children with CP has received only limited attention. Fascial manipulation (FM) is a manual treatment that takes a different approach, targeting the deep fascia rather than focusing on the muscle fascicles, as in more frequently used stretching. Interventions targeting the deep fascia, particularly procedures scheduled before the onset of contractures and deformities, may be an essential strategy for improving motor function in this population.

The fascia consists of collagen fibers, loose connective tissue, and hyaluronic acid (HA) [32]. HA is a polysaccharide in the ECM of connective tissues [33]. In muscle tissue, HA functions as a lubricant within the endomysium, perimysium, and epimysium to facilitate the sliding of muscle fibers during movement [32]. Variations in the viscosity of HA within the fascia occur with mechanical loading and influence the fascia’s mechanical behavior and structure. During loading, viscoelasticity is reduced, and during rest, HA regains a viscous state [32]. The capsules of the muscle spindles that sense muscle stretch are connected to the perimysium, attach in multiple directions, and extend into the deep muscular fascia. This suggests that fascial tension may influence spindle sensitivity and contribute to increased muscle hyper-resistance [10,34-36]. Therefore, modulating fascial tension may represent a feasible and promising approach to maintaining the functional integrity of the muscle spindles to modulate the peripheral component of spasticity [35,36].

A trademarked manual therapy method for this type of fascial tension modulation is the Stecco FM protocol developed by physiotherapist Luigi Stecco [37-39]. FM relies on deep friction to restore gliding of the tissues of the deep fascia, aiming to influence the hyaluronan within the fascia connected to the muscle fibers [38,39]. Emerging evidence has shown increased joint ROM in the upper limb following FM, possibly due to decreased viscosity of the ECM [39,40]. Treatment points are selected based on a thorough assessment, which includes the patient’s medical history, movement analysis, and palpation tests [41]. For the treatment of spasticity, FM is directed to the spastic body parts to target the deep fascia associated with muscles, including the aponeurotic and epimysial fascia.

In children with CP, FM has emerged as a promising treatment for the upper limbs, as it reduces spasticity, increases ROM, and improves muscle strength [42]. Additionally, hyaluronidase injections applied to spastic upper extremities in adult patients, with injection points chosen based on clinical reasoning determined by FM, have shown positive effects on both active and passive movement [34]. This study also supported the application of this treatment to more segments than only the most spastic ones [34]. Notably, FM has demonstrated similar effects [38-40]. A qualitative interview study [43] conducted in Finland demonstrated that the inclusion of FM within neurological physiotherapy facilitated active movement and increased passive ROM for children with CP [43].

Although studies on FM are increasing, the evidence favoring its use remains limited, with pain frequently used as the primary outcome measure [36]. Despite clinical experience supporting the use of FM in the rehabilitation of children with CP, the lack of evidence, particularly regarding its effects on the lower extremities, highlights the need for further investigation into the potential of FM as an effective intervention to increase ROM and reduce spasticity, thereby enhancing physical function in this population.

This study is a 2-arm pilot RCT with an 8-week intervention period and a convergent mixed methods design. Quantitative data will be collected through preintervention, acute response, and postintervention assessments, while qualitative data will be collected through semistructured interviews conducted after completion of each child’s intervention [45]. The quantitative and qualitative findings will be integrated during data interpretation to provide complementary information regarding the feasibility and acceptability of the study procedures and the preliminary effects of the interventions [46].

Participants will be randomly allocated in a 1:1 ratio to 1 of 2 intervention groups. One group will receive targeted FM once weekly for 8 weeks, while the comparison group will receive traditional stretching once weekly for the same period (Figure 1). The schedule of enrollment, interventions, and assessments is presented in Table 1.

This study is conducted in collaboration among Orton Hospital (hereafter, Orton), the New Children’s Hospital, HUS Helsinki University Hospital, and Arcada University of Applied Sciences. Recruitment began in October 2024, and the study is expected to be completed in December 2027.

The study design is convergent, meaning that the interventions, assessments, and qualitative interview data are collected, analyzed, and reported simultaneously [47].

Twenty children fulfilling the eligibility criteria shown in Textbox 1 will be included.

This pilot RCT is designed to assess the feasibility and acceptability of the trial procedures and interventions and to inform the design of a future definitive RCT. The sample size was therefore determined based on feasibility considerations rather than on statistical power to detect treatment effects. A total sample of 20 participants (10 per group) was considered appropriate to assess key feasibility outcomes, including recruitment and retention, intervention adherence, and completion of outcome assessments, while also providing preliminary estimates of outcome variability to inform the planning of a future definitive trial. Consistent with recommendations for pilot and feasibility trials, the sample size was justified according to the objectives and feasibility outcomes of the pilot rather than on formal hypothesis testing of intervention effects [48,49]. Secondary clinical outcomes will be considered exploratory and will not be used to determine the sample size.

Participants are being recruited through the patient register of the Helsinki University Hospital New Children’s Hospital (HUS/ULS). A research coordinator involved in the project at HUS/ULS initially selects from the register those children who meet the inclusion criteria. Subsequently, once the participants are identified and contacted, an information letter is sent to their families regarding their preliminary willingness to participate in the study. The letter provides information about the study, its purpose, and what participation in the project entails for the participants and their families. Upon expression of interest, participants will be screened against the eligibility criteria, and the participant information sheet and consent form will be sent to prospective participants via email. If the participant or guardian refuses, a new participant will be identified from the register. The recruitment process, which started between August and September 2024, will end when the required numbers of participants in both groups are reached.

If both the participant and the guardian preliminarily agree to participate, the distribution to intervention groups is conducted using a computer-based randomization tool. The primary randomization strategy is permuted block randomization with block sizes of 4, stratified by age, sex, and GMFCS level. To account for potential recruitment constraints in this population, a matched-pair allocation procedure is prespecified as a fallback strategy if the primary block randomization procedure cannot be maintained for the remaining participants. Under this procedure, participants will be prospectively matched in pairs based on GMFCS level, age, and sex. Once a matched pair has been formed, the 2 participants will be randomly allocated in a 1:1 ratio to either the FM group or stretching group. This process will be repeated until both intervention groups are filled. The child and the guardian are not informed about their group assignment until they have provided their agreement to participate.

The nature of the intervention precludes blinding of either participants or staff to allocation. However, 2 members of the research team and the study statistician will remain blinded to group allocation during data preparation and statistical analysis to minimize the risk of bias in data interpretation. In the flowchart (Figure 1), the timeline of the study is visualized in relation to the progress of the actual RCT, and the flowchart’s functionality is being evaluated in this pilot.

In this research protocol, FM will be performed once a week for 8 weeks at home or at school by a therapist highly educated in the FM method. The aim of the manual friction treatment of specific points in the deep fascia is to increase the local temperature, as this can reverse the aggregation of HA, thereby restoring the gliding of the underlying fascial layers, enhancing the function of muscle-related deep fascia, enabling movement, and allowing overstrained or painful structures to heal [40,41,50].

The treatment points in FM are selected by a specific protocol that includes clinical history-taking, an assessment of movement and palpation, which directs an individual choice of treatment [38,39]. A specific structured assessment approach is used, with emphasis on chronology, previous musculoskeletal events, and patient symptomatology [39]. Palpatory verification of the deep fascia of the most affected segments defines which centers of coordination points, centers of fusion points, and myofascial chains are treated [39]. Treatment of muscles located both proximally and distally to the primary stiffness along the agonist and antagonist myofascial chains gives better results [34]. Excessively painful areas are initially excluded to enhance patient comfort and therapeutic effectiveness [51]. The same functional movement that is assessed before treatment is assessed again afterward to actively engage with the functional changes and provide experience with altered muscle function.

Passive stretching is performed once a week, supervised by a physiotherapist, in the participant’s home or school. The stretching protocol follows the procedure described by Valadão et al [52], with the addition of stretching the calf muscles [52]. The muscles are stretched by moving the joint to the end-range position. Four sets of 45 seconds of manual passive-static stretches at the pain threshold (ie, the position at which the participant acknowledges an initial pain sensation) are performed for each muscle group. The stretched muscles are the 1- and 2-joint hip flexors, hip adductors, knee flexors, and calf muscles. A Tabata timer on a cellular phone is used to standardize the duration of the stretches. Table 2 shows the protocol for passive stretching. This stretching protocol targets the hip, knee, and ankle, the commonly affected joints of contractures in children with CP [15].

Regular physiotherapy for participants in both groups continues as scheduled. The physiotherapist responsible for each participant’s usual physiotherapy receives information about the intervention study (eg, by telephone) to coordinate the participant’s usual physiotherapy with participation in the intervention study. This arrangement is applied for ethical reasons and is intended to enable a more reliable assessment of the potential added value of including FM in rehabilitation.

Data collection will include semistructured interviews with the participant’s guardian (parent) and the children’s regular physiotherapists in both groups after the final assessment. The number of parent interviews will equal the number of child participants: 10 parents of children who participated in the FM group and 10 parents of children who participated in the stretching group. If the child attends physiotherapy regularly, their physiotherapist will be asked to participate in an interview, resulting in interviews with approximately 20 physiotherapists.

The researcher will contact each interviewee to arrange a suitable interview time. The interview will be conducted either via Microsoft Teams (remote connection) or face-to-face. Each interview will last approximately 30 minutes. The interviews will be recorded with the interviewees’ consent.

As a feasibility pilot RCT, the statistical analysis will focus primarily on descriptive statistics to evaluate trial feasibility, acceptability, and safety. Recruitment, eligibility, retention, and intervention adherence rates will be calculated with corresponding 95% CIs.

The exploratory clinical outcomes will be analyzed separately according to the timing of outcome assessment and the specific research question. Acute outcomes measured at baseline and immediately following the first treatment session will be analyzed using linear mixed-effects models (LMMs), with treatment group, time, and their interaction specified as fixed effects, and a random intercept for individual participants to account for within-participant correlations. For acute outcomes measured at 3 time points (baseline, immediately posttreatment, and 1 h posttreatment), the same LMM framework will be applied with time specified as a 3-level categorical fixed effect to characterize the immediate treatment response and its temporal evolution during the first hour following treatment. Longitudinal outcomes measured at baseline and after the 8-week intervention will be analyzed using a corresponding LMM framework, with treatment group, time, and their interaction specified as fixed effects and participant specified as a random intercept. For outcomes measured at both acute and longitudinal time points, separate analyses will be conducted to address the acute and longitudinal research questions, with the acute analysis including the relevant baseline and posttreatment measurements and the longitudinal analysis comparing baseline with the 8-week postintervention assessment.

Given the pilot nature of the study, these analyses will be considered exploratory and will focus primarily on estimating preliminary treatment effects and their uncertainty rather than on formal hypothesis testing. Treatment effects will be expressed as estimated mean differences with corresponding 95% CIs. No formal adjustments for multiple comparisons for the exploratory clinical outcomes will be made. LMMs will use all available data under the assumption that missing data are missing at random. Estimates of outcome variability, including SDs and within-participant correlations, will be used to inform sample size calculations for a future definitive RCT.

The recorded interviews will be transcribed anonymously, and no personal data will be linked to the anonymized transcripts. The transcribed interviews will be analyzed using a phenomenographic approach to identify and describe the qualitatively different ways in which the phenomenon under study is experienced, conceptualized, perceived, and understood [61]. The steps of the phenomenographic analysis are visualized in Figure 2.

Although the participants constitute a small and purposively selected sample, variation in age, sex, and professional experience will be assumed to provide diverse perspectives and contribute to a broader understanding of the phenomenon under study. To enhance credibility, the most relevant meaning units will be carefully selected during the analysis process. Furthermore, quotations from participants will be used to illustrate similarities and differences within the data and to support the interpretation of the findings. If data collection is conducted over an extended period, there will be a potential risk of inconsistency, which could negatively affect dependability [62]. To minimize this risk, the interview guide will be used consistently throughout the interview. The semistructured interview protocols are shown in the appendices (Multimedia Appendices 1 and 2); all the interviews will be conducted by the same researcher, who will also have regular discussions with the research team to ensure a shared understanding of the study procedures and emerging findings. Data analysis will be performed independently by 2 researchers, who will subsequently compare and discuss their findings to reach consensus. A third researcher will be consulted when necessary to resolve discrepancies. Although transferability is inherently limited due to the small sample size, a rich and transparent description of the research context, participants, sampling procedures, data collection, and data analysis will be provided to enhance the overall trustworthiness of the study and allow readers to judge the potential transferability of the findings.

This study has been designed and will be conducted in strict accordance with the ethical principles outlined in the Declaration of Helsinki [63], as well as national legislation and regulations in Finland, including the Finnish Constitution (731/1999, Sections 6‐23) [64], the Medical Research Act (488/1999) [65], and the Data Protection Act (1050/2018) [66]. As the study involves minors, additional safeguards have been implemented to protect the participants’ welfare, autonomy, and rights. Written informed consent will be obtained from guardians, and assent will be sought from the children themselves. Information about the study will be presented in age-appropriate language to ensure comprehension.

All study-related data will be handled in accordance with the Finnish Data Protection Act (1050/2018), the EU General Data Protection Regulation (GDPR, 2016/679) [67], and institutional data security policies. Study data will be stored securely at the New Children’s Hospital, Helsinki University Hospital (HUS/ULS). Physical materials (eg, consent forms and paper questionnaires) will be stored in locked cabinets in restricted-access areas. Digital data will be stored on secure, HUS-approved platforms that meet institutional and national information security standards.

To ensure participant confidentiality, all research forms, reports, and datasets will be coded with unique study IDs. Personally identifiable information (eg, names and personal identity codes) will be stored separately from the research data and linked only via coded identifiers. Local databases will be password-protected, and access will be limited to authorized study personnel. Interview data collected during the qualitative portion of the study will be fully anonymized prior to analysis, ensuring that individual participants cannot be identified.

All research data will be retained for 15 years following the end of the study, in line with the principles of good clinical practice and institutional guidelines. After the retention period, the data will be securely destroyed, except for anonymized interview material, which will be archived without any identifiable information for potential future research use.

Ethical approval has been obtained from the Regional Ethics Committee of the Hospital District of Helsinki and Uusimaa, which has assessed and approved the protocol (statement ID: HUS/8556/2023). Institutional permission has been granted by HUS’s New Children’s Hospital (research permit ID: HUS/564/2024). The trial is registered in the ClinicalTrials.gov database (trial ID: NCT06837025; accessed on February 20, 2025).

Patients and members of the public were not involved in the design of the research question or study protocol. Participants and their families contribute to the study through their involvement in the intervention and assessment procedures. The outcome measures were selected by the research team with consideration for participant burden and feasibility in children with CP. Once the trial has been published, patients will be informed of the results in a study newsletter suitable for a nonspecialist audience. The results of the study will be submitted for open-access publication.

Participation in the study is voluntary. Written informed consent will be obtained from all guardians or legal representatives of participants below 15 years of age. In addition, assent will be sought from the children themselves, and the researchers will respect the children’s right to refuse or withdraw from the study at any time, without giving any reasons and regardless of parental consent. Information about the study will be presented in age-appropriate language to ensure comprehension. The researchers will adhere to ethical principles that prioritize the autonomy, best interests, and welfare of the participating children.

Participation does not entail any costs for the families and will not interfere with the participants’ regular physiotherapy, which will continue as scheduled. The intervention, either FM or supervised passive stretching, is delivered once weekly and is considered safe and noninvasive.

However, all potential AEs will be actively monitored throughout the study. AEs will be defined as any unfavorable or unintended sign, symptom, or disease temporally associated with the intervention, whether causally related or not. Data on harms will be collected through direct observation, participant or family reports, and standardized AE reporting forms completed by physiotherapists at each intervention session. If any AEs are identified during the study period, these will be reported to the ethics committee within 15 days (approximately 2 wk) and transparently included in the study’s final reporting. SAEs will be reported to the principal investigator within 24 hours and submitted to the ethics committee within 15 days. A summary of AEs and SAEs will be included in any resulting publications. No data safety monitoring board has been and will be established due to the nonpharmacological and low-risk nature of the intervention; however, safety oversight will be managed by the study steering group.

The results of this study will be submitted for publication in peer-reviewed scientific journals and presented at relevant academic conferences. Reporting will follow the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) 2025 statement (Checklist 1) [68] and any applicable extensions, ensuring clarity, transparency, and reproducibility.