Effects of Bar Position and Squat Depth on Trunk and Lower-Limb Muscle Activity and Vertical Ground Reaction Forces During Squat Exercise

Status

Recruiting

Phases

Unknown

Study type

Interventional

Source

CRIS

Registry ID

KCT0011241

Enrollment

Registered

2025-12-03

Start date

2025-12-03

Completion date

Unknown

Last updated

2025-12-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Interventions

Behavioral : Single-group, within-subject randomized crossover exercise intervention. All participants attended two sessions. Session 1: One-repetition maximum (1RM) determination (standardized warm-

progressive loading protocol). Session 2: Surface Electromyography (sEMG) data collection and vertical ground reaction force measurement after Maximum Voluntary Isometric Contraction (MVIC) normaliza

3 repetitions per condition. The presentation order of conditions was randomized (Research Randomizer). Rest between conditions: 2 min. Technique standardization: shoulder-width stance

toes 0–10° out

full-foot contact (“L” foot loading)

thoracic lift with scapular retraction/depression for bracing

neutral lumbar posture

knees tracking toes

hip-hinge initiation with near-vertical trunk

neutral lumbopelvic alignment at depth. Safety and stopping rules: terminate a condition if dizziness, acute pain, undue fatigue, or pain =5/10 occurs. All participants received identical instruction

Eligibility

Sex/Gender

Male

Inclusion criteria

Inclusion criteria: 1. Healthy male adults aged 20–35 years (inclusive). 2. At least 2 years of continuous resistance-training experience. 3. Have performed barbell squats at =80% of 1RM at least once per week for =6 months.

Exclusion criteria

Exclusion criteria: 1. individuals with spinal or lower-limb pain 2. History of surgery involving the spine or lower limb(s). 3. individuals with central or peripheral nervous system lesions 4. Lower-limb length discrepancy = 10 mm. 5. Dermatologic disease, irritation, or open wound at any electrode application site. 6. Known hypersensitivity/allergy to isopropyl alcohol prep pads or Ag/AgCl electrode materials/adhesives.

Design outcomes

Primary

Measure	Time frame
Phase-specific mean surface electromyography (%Maximal Voluntary Isometric Contraction) of rectus femoris, vastus medialis , vastus lateralis, semi tendinosus, biceps femoris, gluteus maximus, rectus abodominis, and erector spinae (root mean square processed and normalized to Maximal Voluntary Isometric Contraction; mean of 3 reps per condition).	—

Secondary

Measure	Time frame
One-repetition maximum (kg): obtained in Session 1 using a standardized progressive loading	—

Countries

Korea, Republic of

Contacts

Public ContactCho hwiyoung

Gachon University

hwiyoung15@gmail.com+82-32-820-4560

Outcome results