Stress Modulation and Dynamic Balance

Study Design

• Type: Pre-post RCT, three parallel groups (n=24 each).
• Setting: Outpatient Clinic & Balance Laboratory, Faculty of Physical Therapy, Kafr Elsheikh University.
• Blinding: Assessor blinded to group allocation.

Population & Eligibility

• Sample: 72 students (both sexes), age 18-25, BMI 18.5-29.9.
• Inclusion: Free from neurological, musculoskeletal, or psychiatric disorders; willing to comply.
• Exclusion: Lower limb/spine injury/surgery (past 6 months), vestibular disorders, pregnancy, medications affecting balance/cognition, regular balance or mind-body training in past 6 months.

Randomization & Groups

• Computer-generated block randomization with opaque sealed envelopes.
• Group A (Balance only): dynamic balance exercises (backward walking, lateral stepping, single-leg forward/lateral reach, tandem gait).
• Group B (Dual-task): same balance exercises plus concurrent cognitive tasks: verbal fluency (e.g., name words starting with letter 'S'), arithmetic (e.g., subtract 7 from 100), or working memory (digit span backward). Cognitive tasks varied across sessions.
• Group C (Control): general health advice (regular daily activities, sleep, nutrition, avoid excessive stress); no structured exercise.

Intervention Protocol

• Duration: 6 weeks, twice/week, each session 20-30 minutes.
• Progression Not Explicitly Stated - but exercises are fixed (10 repetitions or 5-10 m distance per item).
• Safety: Arms crossed over chest in most exercises to eliminate upper limb compensation.

Outcome Measures (assessed at baseline & week 6)

• Primary - Perceived Stress: Arabic PSS-10 (0-40, higher = worse).
• Primary - Dynamic Balance: Balance check 636 (multiaxial wobble board with real-time software) - records anterior/posterior/right/left average deviations and overall stability index.
• Anthropometric: Weight, height, BMI via standard scale.

Statistical Analysis

• Software: SPSS v26.
• Normality: Shapiro-Wilk test.
• Within-group: Paired t-test or Wilcoxon signed-rank.
• Between-groups (post-intervention): One-way ANOVA or Kruskal-Wallis; post-hoc with Bonferroni.
• Power: G*Power (α=0.05, power=0.9, effect size 0.46) → n=72 (24/group, allowing 10% dropout).
• Significance level: p < 0.05.

Hypotheses (Null)

• No significant effect of dual-task exercises on stress modulation or dynamic balance.
• No significant difference between dual-task and balance-only groups.

Limitations Noted in Protocol

• No long-term follow-up.
• Single-site, student population (limited generalizability).
• No objective stress biomarker (only self-report PSS).

Timeline & Ethics

• Participants sign informed consent (Helsinki protocol). Voluntary withdrawal allowed without justification.
• Study period: not explicitly dated; protocol submitted 2026 for master's degree.

Inclusion criteria

• Participants will be included if they meet the following criteria:

Age between 18 and 25 years. Body Mass Index (BMI) ranging from 18.5 to 29.9 kg/m². Both males and females. Apparently healthy individuals with no diagnosed neurological, musculoskeletal, or psychological disorders.

Ability to understand instructions and provide informed consent. Willingness to participate and comply with the study protocol.

Exclusion criteria

• Participants will be excluded if they have any of the following:

Any neurological disorder affecting balance (e.g., vestibular disorders, Parkinson's disease, multiple sclerosis, peripheral neuropathy).

Any recent musculoskeletal injury (within the last 6 months) affecting the lower limbs or spine.

History of lower limb or spinal surgery. Severe visual or auditory impairment not corrected by aids. Use of medications that may affect balance or cognitive function (e.g., sedatives, antidepressants, anxiolytics, antipsychotics).

Pregnancy. Uncontrolled cardiovascular or respiratory disorders limiting exercise tolerance.

Current diagnosis of major psychiatric disorders (e.g., major depression, generalized anxiety disorder, panic disorder).

Regular participation in balance training, mind-body exercises (e.g., yoga, Pilates, tai chi), or structured stress management programs within the last 6 months.

Participation in another interventional study at the same time.