Latissimus Dorsi Activation During Shoulder Extension Exercises
ConditionMuscle Activation
Trial statusRecruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18-40
SponsorHacettepe University
About this trial
This observational, cross-sectional laboratory study at Hacettepe University will examine surface EMG activation of the latissimus dorsi during resisted, dynamic shoulder extension performed at three shoulder flexion angles (30°,60°, 90°, 120°). The primary objective is to quantify latissimus dorsi activation and to determine how elevation angle influences activation; secondary analyses compare synergists.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Age between 18 and 40,
No restriction of the glenohumeral joint,
No complaints related to the shoulder, cervical, or lumbar region in the last 6 months,
No systemic or neurological disease,
Disqualifiers
A body mass index greater than 25 kg/m2
Trial population
Healthy, physically active adults aged 18-40 years, recruited from a university cohort and local community, for a single-visit laboratory EMG study at Hacettepe University. 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; individuals with BMI \>25 kg/m² are excluded
Trial design
Design model
Other
Time perspective
Cross-sectional
Treatments tested in this trial
Exercise
BehavioralStanding with the shoulder in \~30° abduction and external rotation and the elbow extended, participants elevate the arm to three preset flexion angles (30°,60°, 90°, 120°; measured by goniometer) and then perform shoulder extension past the trunk against color-coded elastic bands. Bands are anchored overhead and pulled diagonally downward; the band angle is adjusted to match each shoulder-flexion condition. Tempo is metronome-paced: 3 s concentric, 3 s isometric (at peak), 3 s eccentric. Resistance is individualized using the OMNI Perceived Exertion Scale and titrated until 6-8/10 is reached prior to data capture. Each condition is recorded for 3 repetitions with \~5 s between reps; \~2 min rest is provided between conditions. A brief familiarization (\~3 min per condition) is given, and the order of MVICs and exercise conditions is randomized.
Treatment groups
30 Participants
are divided into 1 treatment groupGroup A: Healthy Active Adults1 intervention
Trial outcomes
Primary outcomes
1
Electromyography
Muscle activation will be assessed with an 8-channel surface EMG system (TeleMyo DTS, Noraxon). Following SENIAM, bipolar Ag/AgCl electrodes (2 cm inter-electrode distance) will be placed over medial and lateral latissimus dorsi, teres major, infraspinatus, posterior deltoid, and triceps brachii, secured with double-sided tape. Before exercise, MVICs will be obtained on the dominant arm by the same assessor (3 × 5 s with 30 s between trials and 2 min between muscles) using standardized, literature-based positions with verbal encouragement.The exercise protocol will consist of elastic-band resisted shoulder extension performed for three repetitions (3 s concentric-3 s isometric-3 s eccentric) with 5 s between repetitions and 2 min rest between conditions, while EMG from all target muscles is recorded and timing is controlled by a metronome.
Time frame
Baseline (Day 1)Secondary outcomes
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.
Time frame
Baseline (Day 1)Sponsors and contacts
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Source ClinicalTrials.gov