Latissimus Dorsi Activity During Different Exercises (L-DORSI-EMG)

Investigation of Latissimus Dorsi Muscle Activation During Different Exercises

This single-visit, laboratory study will quantify latissimus dorsi activation during standardized band/body-weight exercises commonly used in rehabilitation (e.g., standing bent-over row, inferior glide, seated press-up, body-lifting). Healthy, physically active adults (18-40 y; Tegner ≥5) will perform three repetitions per exercise with metronome-paced phases (≈3 s concentric, 3 s isometric, 3 s eccentric), 5-s rest between repetitions and 2-min between exercises; load will be individualized to reach OMNI RPE 6-8. Surface EMG (TeleMyo DTS; Noraxon) will be recorded from the latissimus dorsi (medial and lateral) and selected synergists (teres major, infraspinatus, posterior deltoid, triceps); electrode placement will follow SENIAM recommendations. Signals will be band-pass filtered (20-500 Hz), rectified, RMS-smoothed with a 100-ms window, and normalized to %MVIC using standardized MVC tests; exercise/MVC order will be randomized to limit bias. The primary outcome is mean normalized EMG amplitude per exercise; secondary outcomes include peak amplitude and categorical activation levels (low ≤20% MVIC, moderate 21-40%, high 41-60%, very high >60%). The study involves minimal risk (possible mild skin irritation under electrodes and transient post-exercise fatigue).

Study Overview

• Status: Recruiting
• Conditions: Muscle Activation
• Intervention / Treatment: Behavioral: Exercise

Detailed Description

The latissimus dorsi (LD) originates from the spinous processes of the lower six thoracic vertebrae and the thoracolumbar fascia/iliac crest, and-together with the teres major-attaches to the medial lip of the intertubercular groove of the humerus. Functionally, LD contributes to shoulder adduction, internal rotation, and extension, linking the upper limb to the trunk. Alongside the rotator cuff, prevention of superior translation of the humeral head may be provided by the glenohumeral adductors (pectoralis major and LD) acting as humeral head depressors via a medio-inferior vector created by their tendon orientation. From an osteokinematic perspective, LD may protect against subacromial pain by facilitating inferior glide of the humeral head on the glenoid.

Selecting an appropriate strengthening exercise is critical to restore muscle performance and functional arm elevation in patients with shoulder injury or dysfunction. The literature emphasizes exercises targeting activation of the rotator cuff and scapulothoracic muscles that contribute to functional elevation. Surface electromyography (sEMG) is commonly used to guide exercise selection and progression by quantifying a muscle's contribution across different exercises, thereby enabling evidence-based advancement in strengthening programs.

However, much of the existing LD literature centers on lateral pull-down variations, with limited data for rehabilitation-relevant tasks such as low row, inferior glide, bent-over row (with trunk flexion), seated press-up, and body-lifting. Focusing on a single exercise limits clinical decision-making for shoulder rehabilitation (exercise selection and progression). Therefore, to support a scientific, evidence-based progression for LD strengthening in rehabilitation, this study was planned to obtain comprehensive sEMG data across multiple exercises.

Aim: To examine LD EMG activation levels during different exercises and determine between-exercise differences.

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Altındag
    • Ankara, Altındag, Turkey (Türkiye), 06100
      • Recruiting
      • Hacettepe University
      • Contact: Kubra Caylan Gurses, Research Assistant; Phone Number: +90 312-305 25 25-186; Email: kubracaylan@hacettepe.edu.tr
      • Sub-Investigator: Gizem Soylu, MSc
      • Sub-Investigator: Kubra Caylan Gurses, MSc
      • Sub-Investigator: Ceyda Sevinc, PhD

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Healthy, physically active adults aged 18-40 years. Eligibility requires Tegner ≥5, full glenohumeral range of motion, no shoulder/cervical/lumbar complaints in the past 6 months, and no systemic or neurological disease.

Description

Inclusion Criteria:

• Age 18-40 years
• No range-of-motion restriction at the glenohumeral joint
• No shoulder, cervical, or lumbar region complaints/injury within the past 6 months
• No systemic or neurological disease
• Competent to consent and provides written informed consent
• Tegner Activity Scale ≥ 5

Exclusion Criteria:

• Body mass index (BMI) > 25 kg/m²

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Healthy adults; Single-visit laboratory cohort. Physically active adults perform exercises; surface EMG is recorded from the latissimus dorsi

Behavioral: Exercise; Participants will perform six standardized pulling tasks-inferior glide, low row, seated row, bent-over row, seated press-up, and body lifting-using a resistance band or body weight. Each exercise is done for 3 repetitions with ~5 s between reps and ~2 min between exercises. Resisted exercises follow a metronome-paced 3 s concentric / 3 s isometric / 3 s eccentric tempo; purely isometric tasks are held for 3 s. Load is individualized with the OMNI 0-10 scale and increased during up to 10 familiarization reps until perceived exertion reaches 6-8/10. Exercise order is randomized to minimize ordering effects.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Electromyography	Surface EMG from the latissimus dorsi (medial and lateral sites) will be recorded with an 8-channel system (TeleMyo DTS; Noraxon). Skin will be shaved and cleaned with 70% isopropyl alcohol; bipolar Ag/AgCl electrodes will be placed per SENIAM with a 2 cm inter-electrode distance (MLD ~lateral to T9; LLD ~4 cm inferior to the scapular inferior angle, midway between the spine and lateral trunk). A synchronized video (Logitech C920) will mark movement onset/offset and will be deleted after analysis (no copies kept). Signals will be normalized to %MVIC using three 5-s MVIC trials (30-s rest between trials; ~2-min between muscles) performed in standardized positions with verbal encouragement. The outcome is the mean %MVIC during the steady phase of each exercise.	Baseline (Day 1)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Electromyography-Other muscles	Surface EMG will also be recorded from teres major, infraspinatus, posterior deltoid, and triceps using the same preparation, SENIAM-based placement, and processing/normalization procedures described above. The outcome is the mean normalized EMG amplitude (%MVIC) during the steady phase of each exercise (isometric: central 3-s window; resisted: concentric 3 sec -isometric 3 sec- eccentric 3 sec).	Baseline (Day 1)
Activity Level	Baseline physical activity will be characterized using the Tegner Activity Scale (0-10) prior to testing; higher scores indicate greater habitual activity.	Baseline (Day 1)

Collaborators and Investigators

• Sponsor: Hacettepe University

Study record dates

Study Major Dates

• Study Start (Actual): October 12, 2025
• Primary Completion (Estimated): February 25, 2026
• Study Completion (Estimated): February 25, 2026

Study Registration Dates

• First Submitted: December 9, 2025
• First Submitted That Met QC Criteria: December 9, 2025
• First Posted (Estimated): December 22, 2025

Study Record Updates

• Last Update Posted (Actual): December 29, 2025
• Last Update Submitted That Met QC Criteria: December 22, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Shoulder; Electromyography; Latissimus Dorsi
• Additional Relevant MeSH Terms: Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Exercise
• Other Study ID Numbers: LDORSI-EMG

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No individual participant data (IPD) will be shared. De-identified aggregate results will be disseminated in publications. The dataset includes physiological signals; synchronized videos are deleted after analysis.

Drug and device information, study documents

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