NCT07418892

Effects of Resisted Versus Unresisted Sprint Training on Sprint Force-Velocity Profile in Youth Footballers

Effects of Resisted Versus Non-resisted Sprint Training on Countermovement Jump and Sprint Force-velocity Profile in Youth Footballers: a Randomised Controlled Trial

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 44 (actual)
• Sponsor: Federal University of Vicosa · Academic / Other
• Sex: Male
• Age: 13 Years – 17 Years
• Healthy volunteers: Not accepted

Summary

This randomised, controlled, two-arm trial evaluates whether light resisted sprint training (sled towing at 20% of body mass) produces superior improvements in 30 m sprint mechanical outputs compared with matched-dose unresisted sprint training in youth footballers. Participants complete two supervised sessions per week for six consecutive weeks, integrated into normal academy microcycles on the same artificial-turf surface. Primary outcomes are changes in sprint-derived force-velocity-power profile parameters and 30 m sprint performance, with secondary outcomes including countermovement jump height and anthropometrics.

Detailed description

The study uses a parallel-group randomised design. Allocation is stratified by squad category (Under-14 and Juvenile) with simple randomisation within strata using computer-generated random numbers prepared by a researcher not involved in training delivery. The intervention is delivered on a third-generation artificial-turf pitch at a youth academy integrated within a professional development pathway. Forty-four outfield players from two squads are enrolled. Both arms complete 20 m maximal sprints with identical volume and rest structure (3 sets × 5 repetitions, 45 s inter-repetition rest, 3 min inter-set rest). The experimental arm performs sled towing at 20% body mass (sled tare 3 kg plus plates), whereas the comparator arm performs unresisted maximal sprints. No additional lower-limb strength or speed work beyond the head coach's standard plan is introduced during the intervention period. Primary outcomes are derived from 30 m sprint profiling, using high-speed video and the MySprint application to compute split times and estimate sprint mechanical variables within the Morin-Samozino framework. Outcome assessors/video analysts and the statistician are blinded to group codes, while full participant blinding is not feasible due to the presence of the sled.

Conditions

• Sprint Force-Velocity-Power Profile
• Football (Soccer) Sprint Performance

Interventions

Type	Name	Description
OTHER	Resisted Sprint Training	20 m maximal sprints towing a sled loaded to 20% of individual body mass (sled tare 3 kg; plates added). 3 sets × 5 repetitions, 45 s inter-rep rest, 3 min inter-set rest; two supervised sessions/week for six weeks, conducted at the start of squad training, on the same artificial-turf surface.
OTHER	Unresisted Sprint Training	20 m maximal sprints without external resistance; dose and rest schedule identical to RST (3 × 5 × 20 m; 45 s; 3 min); two sessions/week for six weeks; same surface and session placement; standard team training continues.

Timeline

• Start date: 2024-08-01
• Primary completion: 2024-09-20
• Completion: 2024-09-20
• First posted: 2026-02-18
• Last updated: 2026-02-18

Locations

1 site across 1 country: Colombia