Intramuscular injection is one of the most common invasive procedures in childhood and is frequently associated with pain and fear. These negative experiences may affect children's attitudes toward healthcare and complicate nursing care. Therefore, using non-pharmacological methods is essential for promoting child-friendly services. This study aims to evaluate the effects of the Helfer Skin Tap and vibration techniques on pain and fear levels in children aged 5-10 years during intramuscular injections.

The study is designed as a parallel, three-arm randomized controlled trial conducted in the Pediatric Emergency Clinic of Ege University Hospital. Participants will be allocated by simple randomization to Helfer Skin Tap, vibration, or standard care. Sample size was calculated with G*Power 3.1 using a repeated-measures within-between interaction model with two time points (T0-T1), α=0.05, and power=0.80. Assuming a medium effect size (f=0.25) based on previous studies, at least 159 children are required. Allowing for 15% attrition, the final sample will include 186 participants (62 per group).

Data will be collected using a Child Information Form including sociodemographic characteristics and prior injection experiences. A Procedure Record Form will document randomization, assigned group, medication, dose, injection site, duration, child's position, and parental presence.

Pain and fear will be assessed immediately before (T0) and after (T1) the injection. Pain will be measured with the Wong-Baker FACES Pain Rating Scale (0-10) and fear with the Children's Fear Scale (0-4). Ratings will be obtained independently from the child, parent, and observing nurse.

The procedure will be video-recorded to enable objective evaluation of behavioral responses. Recordings will be scored by an independent blinded expert using standardized criteria. Videos will be used only for research purposes, with identifying features concealed, stored in coded format, and destroyed after study completion.

Intramuscular injection is one of the most frequently performed invasive procedures in childhood and is often associated with pain and fear. This situation can negatively affect children's healthcare experiences and cause difficulties for nurses in the care process. The use of non-pharmacological methods to reduce pain and fear is important for the development of child-friendly healthcare services. This project aims to evaluate the effect of the Helfer Skin Tap and vibration techniques used during intramuscular injections in children aged 5-10 years on the levels of pain and fear experienced by children.

The study was designed as a parallel, three-arm, randomized controlled experimental study at the Ege University Hospital Pediatric Emergency Clinic. Participants will be divided into three groups using simple random sampling; the first group will receive the Helfer Skin Tap technique, the second group will receive the vibration technique, and the third group will be the standard care control group. The sample size was calculated using the G*Power 3.1 program. Since the study involved three groups (Helfer Skin Tap, vibration, and control) and measurements at two time points (T0-T1), a 'within-between interaction' model was used for the analysis of variance for repeated measures. The Type I error level was set at α=0.05 and power (1-β)=0.80. Considering the effect sizes in similar intervention studies in the literature, a medium effect size (f=0.25) was assumed (Kurt et al., 2024). With these parameters, a total of at least 159 participants (approximately 53 children/group) are required. Considering possible losses, the sample size was planned to be 186 children (62 children/group) with a 15% increase. The Child Information Form, prepared by researchers in line with the relevant literature (Kurt et al., 2024), contains information on the children's sociodemographic characteristics (age, gender, height, weight, presence of other children in the family) and their experience with intramuscular injections (previous intramuscular injections, reactions to previous experiences). The Procedure Record Form will record randomization information, the study group to which the child was assigned (Helfer Skin Tap, vibration, or control), and technical information related to the injection (drug, dose, application site, procedure duration, child's position, and parent's presence during the procedure).

Children's pain and fear levels will be assessed at two time points: before the procedure (T0: immediately before the injection begins) and after the procedure (T1: immediately after the injection ends). Pain levels will be measured using the Wong-Baker FACES Pain Rating Scale (0-10 points), and fear levels will be measured using the Children's Fear Scale (CFS, 0-4 points). These assessments will be performed independently by the child, the parent, and the nurse observing the procedure.

Additionally, the intramuscular injection process will be video-recorded to objectively assess children's behavioral responses. The video recordings will be viewed by an expert evaluator who is not involved in the study and is unaware of the group assignments (blinded). The child's behavioral responses to pain and fear will be scored according to predefined standard evaluation criteria. Camera recordings will be used solely for scientific purposes; faces and identifying information will be concealed; recordings will be stored in coded form and will be destroyed after the study is completed.

Inclusion Criteria:

• The child must be in the 5-10 age group
• Intramuscular injection must be performed,
• The child must be able to communicate in Turkish,
• Verbal/written consent must be obtained from the parents/legal guardians

Exclusion Criteria:

• Known neurological disorders,
• Inability to communicate cognitively,
• Chronic pain syndrome
• Acute and life-threatening clinical condition