Effects Of Passive Static Stretching On Hip Range Of Motion In Patients With Joint Pathologies And Healthy Individuals: A Pilot Study
Conditions: Hip Joint Disorders, Recovery After Total Hip Arthroplasty, Healthy Individuals
Sponsor: Omicron beta research

Effects of Passive Static Stretching on Hip Range of Motion in 
Patients with Joint Pathologies and Healthy Individuals: A Pilot Study
Principal Investigator: 
Emanuele Novelli
Affiliation / Organization: 
Omicron Beta
Contact Information:
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Mobile: +39 349 538 7885
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Email: enovelli.osteopatia@gmail.com
Date: March 2026
Location: Italy

1. Introduction and Study Overview
This pilot study aimed to explore the effects of a four-week passive static stretching program on hip 
mobility in three groups: patients who had undergone total hip arthroplasty (THA), patients with 
chronic non-surgical hip pain, and healthy individuals with no history of hip problems. The main 
goal was to investigate whether the stretching protocol could improve hip flexion and abduction, 
while also assessing feasibility, safety, and adherence to the intervention.
We enrolled 12 participants in total (7 women and 5 men; mean age 52.5 ± 6.8 years), divided into 
three homogeneous groups of four participants each. Group A included patients who had undergone 
THA, Group B consisted of patients with chronic hip pain, and Group C comprised healthy 
volunteers. Participants were selected based on their ability to complete the protocol, absence of 
neurological or musculoskeletal conditions affecting motor control, and no contraindications to 
stretching. All participants provided written informed consent before enrollment.
2. Study Design and Intervention
The study followed a prospective, non-randomized design and adhered to the CONSORT extension 
for pilot and feasibility studies. This approach ensured transparency and rigor, even though the 
small sample size meant that all analyses were primarily exploratory.
The stretching program consisted of assisted hip flexion and abduction exercises, each held for 30 
seconds, performed three times per week for four consecutive weeks (12 sessions in total). Every 
session was supervised by an experienced kinesiologist, who ensured proper positioning, correct 
biomechanical alignment, and submaximal intensity to avoid pain or injury. All sessions took place 
in a controlled laboratory environment to minimize variability in temperature, lighting, noise, and 
equipment.
Participants were asked to maintain their usual daily routines and refrain from initiating any new 
hip-specific rehabilitation or medication during the study period.
3. Outcome Measures
The primary outcome was hip range of motion (ROM), measured in flexion and abduction using 
high-precision triaxial electronic sensors (Sensorize) equipped with accelerometers and gyroscopes. 
Measurements were taken both before and after the intervention by the same assessor with 
extensive experience, ensuring consistency and reliability.
Secondary outcomes included treatment feasibility, adherence, and safety. Although participants and 
therapists could not be blinded due to the nature of the intervention, outcome assessors and data 
analysts were blinded to group allocation.
4. Statistical Analysis Plan
Given the small sample size (n=4 per group), analyses were mostly descriptive. Continuous 
variables were summarized using means and standard deviations, while categorical data were 
presented as counts and percentages.

Pre–post comparisons of hip ROM within each group were performed using two-tailed paired t-
tests, with a significance threshold of p < 0.05. Analyses were conducted separately for flexion and 
abduction. No post hoc or subgroup analyses were performed. Missing data were either imputed or 
excluded, depending on availability.
5. Baseline Characteristics
Participants ranged from 32 to 77 years of age, with diverse occupational and activity backgrounds. 
Some reported unilateral or bilateral hip pain, while others were asymptomatic. Baseline ROM 
reflected these differences:
6. Results and Interpretation
After completing the 4-week program, all groups showed significant improvements in hip flexion 
and abduction (p < 0.05). No adverse events were reported, and all participants attended every 
session, indicating high adherence and feasibility.
Given the exploratory nature of this pilot study, results should be interpreted cautiously. 
Nonetheless, the findings suggest that passive static stretching is safe, well-tolerated, and potentially 
beneficial for improving hip mobility in both clinical and healthy populations.
Group
n
Flexion (°)
Abduction (°)
A (THA)
4 78.2 ± 5.4
27.4 ± 3.1
B (Chronic hip pain)
4 89.6 ± 4.9
33.7 ± 2.8
C (Healthy)
4 101.3 ± 6.2
40.9 ± 4.1