Effects of Core Exercise on Posture and Trunk Endurance in Sedentary Males

Increased sedentary lifestyles due to modern technological advancements have negatively impacted posture and trunk stability. Proper posture relies on balanced dorsal and ventral muscles, trunk stabilization, and joint flexibility. Deviations in these factors may lead to postural abnormalities and, over time, structural deformities. Early detection and intervention through corrective exercises can mitigate these issues. Various measurement techniques, including 2D and 3D scanning, allow for objective posture assessment. Core stabilization exercises have been shown to influence spinal alignment and muscle endurance, improving postural control. However, limited research focuses on young adult males. This study aimed to evaluate the effects of an 8-week core exercise program on posture and trunk endurance in sedentary university students.

A randomized controlled trial was conducted on male university students at the University of Novi Sad, Serbia. Participants were recruited through an open call, and those with prior musculoskeletal, neurological, or metabolic conditions were excluded. The final sample included 138 participants divided into an experimental group (EG) and a control group (CG). The EG followed an 8-week core stabilization program, while the CG did not receive any intervention.

Postural assessments were conducted using CONTEMPLAS TEMPLO software with 2D and 3D analysis protocols. Measurements included the Fröner Posture Index (PI) and the Kyphosis-Inclination-Lordosis (KIL) scheme, evaluating thoracic kyphosis, cervico-lumbar, and lumbar-gluteal angles. Trunk endurance was assessed through the Sorensen Back Extensor Test (BET), the Abdominal Flexor Endurance Test (FET), and the Double Leg Lowering Test (DLL). The intervention program consisted of progressive core stabilization exercises, increasing in difficulty from basic planks to exercises on unstable surfaces.

The experimental group underwent structured core training three times a week for eight weeks. The program included exercises to enhance mobility and strengthen the neck, shoulders, pelvis, and hips, with a focus on stabilizing the spine through anti-flexion, anti-extension, and anti-rotation movements. Exercises progressed from static planks to dynamic and unstable surface training. The control group did not participate in any structured physical activity.

At the beginning of the 21st century, technological and social changes have significantly impacted human health and development. Increased reliance on technology has contributed to a sedentary lifestyle, leading to reduced physical activity and associated health issues. One major concern is the effect of prolonged sitting on posture and trunk stability. Proper posture is essential for maintaining musculoskeletal health and functional movement. It depends on the balance between dorsal and ventral muscles, the strength of trunk stabilizers, and the flexibility of joints.

Misalignments in body posture, especially in the sagittal plane, can lead to postural abnormalities. If left untreated, these abnormalities may develop into structural deformities. The biomechanics of the spine are particularly sensitive to prolonged external forces, which can result in muscular imbalances and impaired postural reflexes. Addressing these issues through early intervention and corrective exercises can help restore proper alignment and reduce the risk of developing chronic conditions.

Traditional postural assessments often rely on visual inspection, which lacks scientific precision. Recent advancements in technology, such as 2D and 3D scanning techniques, allow for more objective posture evaluation. The CONTEMPLAS TEMPLO software is one such tool that provides detailed postural analysis based on reference points, angles, and postural indices. Using such technologies, researchers can quantitatively assess changes in posture before and after intervention programs.

Several studies have demonstrated the benefits of core stabilization exercises in improving postural control and trunk endurance. These exercises have been shown to correct thoracic and lumbar curvatures, enhance muscular balance, and improve movement patterns. However, most posture-related studies focus on children and adolescents. There is limited research on postural interventions in young adult males. The present study aims to investigate the effects of an 8-week core exercise program on posture and trunk endurance in sedentary university students.

The study recruited male university students from the University of Novi Sad, Serbia. Participants were selected through an open application process, with an initial sample of 250 individuals. After an initial screening, 230 participants met the inclusion criteria. The selection process was designed to ensure a homogeneous sample by excluding individuals with prior musculoskeletal, neurological, or metabolic conditions that could affect balance and posture.

After randomization, 230 participants were divided into two groups:

Measurements Anthropometric Measurements Height: Measured using Martin's anthropometry Weight: Measured using a digital scale BMI: Calculated based on height and weight Postural Assessment Postural disorders were evaluated using the CONTEMPLAS TEMPLO photometric system, which analyzes body alignment based on 2D and 3D protocols.

2D Analysis Fröner Posture Index (PI): Calculated based on spinal curvatures, including thoracic kyphosis and lumbar lordosis. PI values range from 0.8 to 1.7, with optimal posture between 1.0 and 1.2.

Kyphosis-Inclination-Lordosis (KIL) Scheme: Evaluates:

Thoracic Kyphosis Index (TKI) Cervico-Lumbar Lead Angle (CCL) Lumbar-Gluteal Lead Angle (LGL) The KIL scheme helps assess postural asymmetry and spinal curvatures.

3D Analysis

The 3D spine analysis protocol provides a comprehensive assessment of the sagittal and frontal posture, including:

Shoulder and pelvis alignment Spinal curvature relative to the vertical reference line

Trunk Muscle Endurance Tests Sorensen Back Extensor Test (BET): Measures back extensor endurance in a prone position. Participants attempt to maintain a horizontal position for as long as possible.

Abdominal Flexor Endurance Test (FET): Measures abdominal endurance with participants sitting at a 50-degree incline and maintaining the position.

Double Leg Lowering Test (DLL): Assesses core stability by measuring the angle at which participants can control pelvic movement during leg lowering.

Intervention Protocol

Control Group (CG) The control group received no intervention and continued their regular daily activities.

Experimental Group (EG)

The experimental group participated in an 8-week core stabilization program, conducted three times per week. Each session lasted 30 minutes and consisted of:

Weeks 1-2:

Basic stabilization exercises (planks, forearm support, quadruped positioning) Core activation drills (McGill curl-up, plank walking)

Weeks 3-4:

Additional movement patterns (superman holds, alternating hand and foot raises) Rotation-based stabilization (faceplate switches)

Weeks 5-6:

Introduction of unstable surfaces (stability ball, balance boards) Unilateral exercises (single-leg planks, single-arm support)

Weeks 7-8:

Advanced core exercises (stirring the pot, one-arm side planks) Increased resistance and endurance-based progressions The intensity of the program was gradually increased based on participants' progress.

Eligibility Criteria:
Inclusion Criteria:

* no injuries within the past six months,
* no other medical conditions, including COVID-19,
* no scheduled physical activity in the previous three months,
* we considered the experimental programs valid if participants completed at least 80% of all training sessions.

Exclusion Criteria:

* had a history of neurological or musculoskeletal disorders,
* had clinical conditions that could affect balance, such as motor disorders, diabetes, heart disease, stroke, vision problems, thyroid issues, or issues with nerves or blood vessels.