Football (Soccer) Sprint Performance, Sprint Force-Velocity-Power Profile
Conditions
Keywords
Resisted sprint training, Sled towing, Unresisted sprinting, Youth footballers, force-velocity profile, Horizontal power, RF-peak, Countermovement jump
Brief 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.
Interventions
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.
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.
Sponsors
Federal University of Vicosa
Universidad de Antioquia
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
13 Years to 17 Years
Healthy volunteers
No
Inclusion criteria
* Male football (soccer) player aged 13 to 17 years. * Registered Under-14 or Juvenile player in an organized football program/club/league. * At least 1 year of organized football experience. * Current health-system affiliation (e.g., EPS). * Provided informed assent; parent/guardian provided written informed consent (for minors). * Able to attend and comply with the sessional training and testing protocol.
Exclusion criteria
* Current musculoskeletal complaint or injury at baseline. * Ongoing rehabilitation at baseline. * Logistical constraints preventing participation in the sessional protocol (e.g., inability to attend required sessions/assessments). * Injury incurred during the intervention that prevents safe continuation (participant will be withdrawn).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline to post-intervention in best 30 m sprint time | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Best (fastest) 30 m sprint time, expressed in seconds (s). The reported value is the best 30 m time (s). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline to post-intervention in peak sprint velocity | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Peak velocity reached during the sprint assessment, expressed in meters per second (m/s). |
| Change from baseline to post-intervention in rate of decrease in RF with velocity (DRF) | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Sprint-derived rate of decrease in RF with velocity (DRF), expressed as % per m. |
| Change from baseline to post-intervention in peak ratio of horizontal force (RF_peak) | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Sprint-derived peak ratio of horizontal force (RF\_peak), expressed as percentage (%). |
| Change from baseline to post-intervention in ratio of horizontal force (RF) | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Sprint-derived ratio of horizontal force (RF), expressed as percentage (%). |
| Change from baseline to post-intervention in maximal horizontal power (Pmax) | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Sprint-derived maximal horizontal power (Pmax), expressed relative to body mass (W/kg). |
| Change from baseline to post-intervention in theoretical maximal running velocity (V0) | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Sprint-derived theoretical maximal running velocity (V0), expressed in meters per second (m/s). |
| Change from baseline to post-intervention in theoretical maximal horizontal force (F0) | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Sprint-derived theoretical maximal horizontal force (F0), expressed relative to body mass (N/kg). |
| Change from baseline to post-intervention in countermovement jump (CMJ) height | From baseline assessment (within 1 week prior to first training session) to post-intervention assessment (within 1 week after the final training session), over the 6-week intervention period. | Countermovement jump (CMJ) height, expressed in centimeters (cm). The reported value is CMJ height (cm). |
Countries
Colombia
Outcome results
None listed