Effects of Different Sled Loads on Sprint and Neuromuscular Performance in Young Male Football Players: An 8-Week Periodized Field Study

NCT07797920 | Not Yet Recruiting

• 1 other identifier: BEU-ANT-MZK-01
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this 8-week periodized field study is to investigate and compare the acute and chronic effects of three different sled towing loads (10%, 15%, and 20% of body weight \[BW\]) on sprint performance (5m, 10m, 15m) and neuromuscular characteristics (Squat Jump \[SJ\], Countermovement Jump \[CMJ\], Drop Jump \[DJ\], and Reactive Strength Index \[RSI\]) in trained male youth football players aged 13-14 years. While all other training variables (distance, frequency, volume, and rest intervals) are standardized, this study aims to identify the optimal sled load that enhances acceleration and horizontal force production without compromising running mechanics during a critical pediatric athletic development window.

Conditions

Athletic Performance; Neuromuscular Adaptations

Keywords

Sled towing; Resisted sprint training; Youth football; Neuromuscular performance; Reactive Strength Index; Acceleration

Outcome Measures

Primary Outcomes (4)

• Linear Sprint Performance (5m, 10m, and 15m Sprint Times)

  Linear sprint performance measured over 5 meters (acceleration), 10 meters, and 15 meters using a high-precision wireless photocell timing system. Times are measured in seconds (s), where lower values indicate better sprint performance.

  Baseline (Pre-test) and 8 weeks (Post-test)

• Squat Jump (SJ) Height

  Lower-limb concentric explosive power output measured via Squat Jump test on a digital contact mat/force platform. Surcharge from arm swing is isolated by keeping hands on hips. Jump height is measured in centimeters (cm), where higher values indicate greater explosive power output.

  Baseline (Pre-test) and 8 weeks (Post-test)

• Countermovement Jump (CMJ) Height

  Stretch-shortening cycle (SSC) performance and lower-limb reactive power measured via Countermovement Jump test on a digital contact mat/force platform. Jump height is recorded in centimeters (cm), where higher values represent superior vertical jump capacity.

  Baseline (Pre-test) and 8 weeks (Post-test)

• Reactive Strength Index (RSI)

  Reactive strength capacity and neuromuscular stiffness assessed via Drop Jump (DJ) test from a 30 cm box. Calculated as jump height (meters) divided by ground contact time (seconds) \[RSI = Jump Height (m) / Contact Time (s)\]. Higher index scores reflect better reactive strength and shorter contact time.

  Baseline (Pre-test) and 8 weeks (Post-test)

Study Arms (3)

Light Sled Load Group (10% BW)

EXPERIMENTAL

Participants perform resisted sprint training using a sled loaded with 10% of their individual body weight (BW). Training is performed 2 sessions/week for 8 weeks (16 sessions) over 15 meters with standardized progression (2-3 sets, 3-4 reps, 2 min inter-repitition rest, 3 min inter-set rest).

Other: Resisted Sled Sprint Training

Moderate Sled Load Group (15% BW)

EXPERIMENTAL

Participants perform resisted sprint training using a sled loaded with 15% of their individual body weight (BW). Training is performed 2 sessions/week for 8 weeks (16 sessions) over 15 meters with standardized progression (2-3 sets, 3-4 reps, 2 min inter-repitition rest, 3 min inter-set rest).

Other: Resisted Sled Sprint Training

Heavy Sled Load Group (20% BW)

EXPERIMENTAL

Participants perform resisted sprint training using a sled loaded with 20% of their individual body weight (BW). Training is performed 2 sessions/week for 8 weeks (16 sessions) over 15 meters with standardized progression (2-3 sets, 3-4 reps, 2 min inter-repitition rest, 3 min inter-set rest).

Other: Resisted Sled Sprint Training

Interventions

Resisted Sled Sprint Training OTHER

An 8-week periodized resisted sprint training protocol using weighted sleds. Sessions are performed twice weekly over a 15-meter sprint distance, immediately following a standardized warm-up. Participants are assigned to sled towing loads equivalent to 10%, 15%, or 20% of their individual body weight (BW). Training volume progresses systematically from 2 sets of 3 repetitions (Weeks 1-2) to 3 sets of 4 repetitions (Weeks 7-8) with 2 minutes of inter-repetition rest and 3 minutes of inter-set rest.

Also known as: Sled Towing

Heavy Sled Load Group (20% BW); Light Sled Load Group (10% BW); Moderate Sled Load Group (15% BW)

Eligibility Criteria

• Age: 13 Years - 14 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Male football players aged chronologically between 13 and 14 years.
• Minimum of 2 years of active, licensed competitive football experience in a club or academy.
• Regular attendance at scheduled team training sessions.
• Written Informed Consent/Assent signed by both the participant (Child Assent Form) and parent/legal guardian (Parental Consent Form).
• Free of severe lower-limb musculoskeletal injuries (e.g., ligament tears, fractures, meniscus injuries) in the past 6 months.

You may not qualify if:

• Chronological age \<13 or \>14 years.
• Presence of chronic, cardiovascular, metabolic, or respiratory conditions (e.g., asthma) that pose risks during high-intensity maximal exercise.
• Regular use of performance-enhancing supplements or medications affecting physiological and neuromuscular responses.
• Absence from more than 10% of prescribed sled training sessions (2 or more sessions out of 16).
• Failure to complete pre- or post-intervention performance testing batteries, or failure to demonstrate maximal effort during testing.
• Concurrent participation in external individual strength, speed, or fitness programs outside the football academy.

Sponsors & Collaborators

• Bitlis Eren University: lead

Study Sites (1)

Bitlis Eren University

Bitlis, Central, 13000, Turkey (Türkiye)

Location

Study Officials

• Muhammed Z Kahraman, PhD

  Bitlis Eren University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Muhammed Z Kahraman, PhD

CONTACT

00904342220000; mzkahraman@beu.edu.tr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor, Department of Coaching Education, Faculty of Sport Sciences, Bitlis Eren University

Model Details: A parallel-group, randomized experimental field design with three active intervention groups (10% BW, 15% BW, and 20% BW sled towing loads). Participants are stratified and allocated into homogeneous groups based on baseline 15-meter sprint performance. All groups receive their respective resisted sprint protocols twice weekly over an 8-week period while maintaining identical overall external training volume, sprint distance (15 m), and rest intervals.

Study Record Dates

• First Submitted: August 27, 2026
• First Posted: September 1, 2026
• Study Start: September 5, 2026
• Primary Completion (Estimated): October 31, 2026
• Study Completion (Estimated): November 15, 2026
• Last Updated: September 1, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)