Acute Effects of Proprioceptive Neuromuscular Facilitation on Hamstring-to-Quadriceps Strength Ratio (Acute Effects)

Acute Effects of Proprioceptive Neuromuscular Facilitation and Static Stretching on Hamstring-to-Quadriceps Strength Ratio in Healthy Young Men

This study aimed to compare the acute effects of proprioceptive neuromuscular facilitation (PNF) and static stretching on hamstring-to-quadriceps (H/Q) strength ratios in healthy young men. A randomized crossover design was used in which participants completed both stretching protocols on separate days. Isokinetic muscle strength and H/Q ratios were assessed following each intervention. The findings provide insight into the immediate effects of different stretching modalities on muscle balance and performance.

Study Overview

• Status: Completed
• Conditions: Muscle Strength; Neuromuscular Function; Muscle Strength Development
• Intervention / Treatment: Other: PNF Stretching; Other: Static Stretching

Detailed Description

The present study investigated the acute effects of two commonly used stretching modalities-proprioceptive neuromuscular facilitation (PNF) and static stretching-on isokinetic muscle strength and hamstring-to-quadriceps (H/Q) ratios in physically active healthy young males. The study employed a randomized crossover design with repeated measures, allowing each participant to complete both experimental conditions under standardized laboratory settings.

Participants attended three sessions: a familiarization session followed by two experimental sessions separated by at least 48 hours. Each experimental session included a standardized warm-up, followed by either PNF or static stretching intervention, and subsequent isokinetic strength testing. Peak torque values for quadriceps (concentric) and hamstrings (concentric and eccentric) were measured using an isokinetic dynamometer at 60°/s. Traditional and functional H/Q ratios were calculated.

The primary aim was to determine whether these stretching modalities produce acute alterations in muscle strength and H/Q ratios. The study also examined whether the type of ratio (traditional vs. functional) significantly influences outcomes. Findings contribute to understanding the neuromuscular implications of stretching in warm-up protocols.

• Study Type: Interventional
• Enrollment (Actual): 23
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Trabzon, Ordu, Giresun, Rize, Artvin, Gümüşhane
    • Gümüşhane, Trabzon, Ordu, Giresun, Rize, Artvin, Gümüşhane, Turkey (Türkiye), 29600
      • Gumushane Univetsity

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age between 18 - 25 years, healthy male individuals
• Physically active (≥3 days/week, ≥30 min/day)

Exclusion Criteria:

• Musculoskeletal injury in the last 6 months
• Any neurological or orthopedic disorder

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PNF Stretching; Participants performed four repetitions of PNF stretching consisting of a 6-second isometric hamstring contraction at approximately 60% of maximal voluntary contraction followed by a 30-second passive stretch. Rest intervals were standardized.	Other: PNF Stretching; Participants performed four repetitions of PNF stretching consisting of a 6-second isometric hamstring contraction at approximately 60% of maximal voluntary contraction followed by a 30-second passive stretch. Rest intervals were standardized.; Other: Static Stretching; Participants performed four repetitions of static hamstring stretching, each lasting 30 seconds, with 30-second rest intervals between repetitions.
Experimental: Static Stretching; Participants performed four repetitions of static hamstring stretching, each lasting 30 seconds, with 30-second rest intervals between repetitions	Other: PNF Stretching; Participants performed four repetitions of PNF stretching consisting of a 6-second isometric hamstring contraction at approximately 60% of maximal voluntary contraction followed by a 30-second passive stretch. Rest intervals were standardized.; Other: Static Stretching; Participants performed four repetitions of static hamstring stretching, each lasting 30 seconds, with 30-second rest intervals between repetitions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hamstring-to-Quadriceps (H/Q) Ratio	Both traditional (Hcon/Qcon) and functional (Hecc/Qcon) ratios were calculated using isokinetic peak torque values.	Immediately after intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quadriceps Concentric Peak Torque	Quadriceps Concentric Peak Torque	Immediately post-intervention
Hamstring Concentric Peak Torque	Hamstring Concentric Peak Torque	Immediately post-intervention
Hamstring Eccentric Peak Torque	Hamstring Eccentric Peak Torque	Immediately post-intervention

Collaborators and Investigators

• Sponsor: Gümüşhane Universıty

Study record dates

Study Major Dates

• Study Start (Actual): March 5, 2025
• Primary Completion (Actual): April 15, 2025
• Study Completion (Actual): April 20, 2025

Study Registration Dates

• First Submitted: May 6, 2026
• First Submitted That Met QC Criteria: May 13, 2026
• First Posted (Actual): May 15, 2026

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 13, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: PNF stretching; Static stretching; Isokinetic strength; Acute effect; Hamstring quadriceps ratio
• Additional Relevant MeSH Terms: Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Therapeutics; Physical Therapy Modalities; Patient Care; Exercise Therapy; Rehabilitation; Aftercare; Continuity of Patient Care; Exercise; Muscle Stretching Exercises
• Other Study ID Numbers: 2025/169

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No