Chest Press Variations and Pectoralis Major Mechanics

Bench Press and Machine Chest Press Elicit Distinct Acute Mechanical Responses in the Pectoralis Major: A Randomized Controlled Study

This randomized controlled study aims to compare the acute effects of bench press (BP) and machine chest press (MCP) exercises on the mechanical properties of the pectoralis major muscle in resistance-trained bodybuilders. Sixteen male athletes are randomly assigned to BP or MCP groups. Both groups perform four sets of ten repetitions at 80% of one-repetition maximum with equalized volume load. Muscle mechanical properties, including oscillation frequency, stiffness, decrement, relaxation time, and creep, are measured using MyotonPRO before and immediately after exercise. The study hypothesizes that BP will induce greater stiffness due to higher stabilization demands, whereas MCP will produce greater increases in oscillation frequency due to more isolated loading.

Study Overview

• Status: Completed
• Conditions: Resistance Training; Muscle Mechanical Properties
• Intervention / Treatment: Behavioral: Bench Press Exercise; Behavioral: Machine Chest Press Exercise

Detailed Description

Exercise selection is a key determinant of acute neuromuscular responses during resistance training. Bench press (BP) and machine chest press (MCP) are widely used exercises targeting the pectoralis major, but they differ biomechanically in stabilization demands and load distribution. While BP requires multi-joint stabilization and increased neuromuscular coordination, MCP provides a guided movement pattern that isolates the pectoralis major.

Despite similar muscle activation reported in previous electromyographic studies, the acute mechanical responses of muscle tissue to these exercises have not been directly compared. Muscle mechanical properties, including oscillation frequency, stiffness, decrement, relaxation time, and creep, provide objective insights into neuromuscular function and fatigue.

In this randomized controlled trial, sixteen male bodybuilders with at least five years of resistance training experience are assigned to BP or MCP groups. Both groups perform four sets of ten repetitions at 80% 1RM. MyotonPRO is used to assess mechanical properties of the pectoralis major before and immediately after exercise.

The primary aim is to determine whether biomechanical differences between BP and MCP produce distinct acute mechanical responses in muscle tissue.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Centre
    • Giresun, Centre, Turkey (Türkiye), 28100
      • Giresun University - Sports Science Faculty

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Male participants
• Aged between 20 and 40 years
• Minimum of 5 years of regular resistance training experience
• Competitive bodybuilding athletes

Exclusion Criteria:

• History of musculoskeletal injury affecting the pectoralis major, shoulder, or upper extremity within the last 12 months
• History of upper extremity surgery
• Use of anabolic steroids or performance-enhancing substances within the last 12 months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Bench Press Group; Participants performed a single-session resistance training protocol consisting of four sets of ten repetitions at 80% of one-repetition maximum using barbell bench press with 2-minute rest intervals between sets.	Behavioral: Bench Press Exercise; Participants performed a resistance training protocol consisting of four sets of ten repetitions at 80% of one-repetition maximum using barbell bench press, with 2-minute rest intervals between sets.
Experimental: Machine Chest Press Group; Participants performed a single-session resistance training protocol consisting of four sets of ten repetitions at 80% of one-repetition maximum using a machine chest press with 2-minute rest intervals between sets.	Behavioral: Machine Chest Press Exercise; Participants performed a resistance training protocol consisting of four sets of ten repetitions at 80% of one-repetition maximum using a machine chest press, with 2-minute rest intervals between sets.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in pectoralis major muscle stiffness measured by MyotonPRO	Muscle stiffness (N/m) of the pectoralis major was measured using MyotonPRO before and immediately after the exercise protocol.	Baseline and immediately post-exercise (within 90 seconds)
Change in oscillation frequency (muscle tone) of the pectoralis major measured by MyotonPRO	Muscle stiffness (N/m) and oscillation frequency (Hz), representing muscle tone, were measured using MyotonPRO before and immediately after the exercise protocol.	Baseline and immediately post-exercise (within 90 seconds)

Collaborators and Investigators

• Sponsor: Nihat Sarıalioğlu

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2025
• Primary Completion (Actual): August 30, 2025
• Study Completion (Actual): December 31, 2025

Study Registration Dates

• First Submitted: April 13, 2026
• First Submitted That Met QC Criteria: April 13, 2026
• First Posted (Actual): April 20, 2026

Study Record Updates

• Last Update Posted (Actual): April 20, 2026
• Last Update Submitted That Met QC Criteria: April 13, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Resistance Training; Myotonometry; Bench Press; Machine Chest Press; Exercise selection
• Other Study ID Numbers: GRU-SBF-NS-05

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared due to the small sample size and to ensure participant confidentiality and data protection.

Drug and device information, study documents

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