Absolute vs Normalized Acceleration and Deceleration Load in Football Microcycles (NORM-ACCDEC)

Comparison of Absolute and Individualized Normalized Acceleration and Deceleration Thresholds Across the Football Microcycle

This observational repeated-measures study investigates differences between absolute and individualized normalized acceleration and deceleration thresholds across the football microcycle. Match-derived locomotor metrics are commonly used to guide training prescription, although match performance may not reflect each player's maximal physical capacity. Therefore, this study monitored under-23 male football players across a full competitive season using 10-Hz GPS technology during training sessions and matches. High-intensity normalized thresholds were defined as 75-100% of individual maximum acceleration and deceleration, and were compared with conventional absolute thresholds (>3 m/s² and <-3 m/s²). The study aims to determine whether normalized approaches provide a more accurate representation of high-intensity locomotor demands across microcycle sessions relative to match load.

Study Overview

• Status: Completed
• Conditions: Athletic Performance; Soccer; Training Load Monitoring
• Intervention / Treatment: Other: External Load Monitoring

Detailed Description

This season-long observational cohort study examined the distribution of acceleration and deceleration external load across the football microcycle using both absolute and individualized normalized thresholds. Twenty-seven under-23 male football players competing at the national level were monitored throughout one competitive season using 10-Hz GPS devices during all training sessions and official matches.

Individual maximum acceleration and deceleration were determined using the average of the three highest values recorded across the season while excluding potential measurement artefacts. High-intensity normalized thresholds were defined as 75-100% of these individual maxima and compared with conventional absolute thresholds (>3 m/s² and <-3 m/s²). Outcome measures included counts and distances of acceleration and deceleration efforts across microcycle days relative to match load, adjusted for playing position.

Generalized linear mixed models were used to evaluate differences between threshold definitions and temporal patterns across the microcycle. The primary objective was to determine whether normalized thresholds provide a more sensitive and ecologically valid characterization of high-intensity locomotor demands compared with fixed absolute thresholds, with implications for training load monitoring and prescription in football.

• Study Type: Observational
• Enrollment (Actual): 27

Contacts and Locations

Study Locations

• Portugal
  • Porto District
    • Maia, Porto District, Portugal, 4475-690
      • University of Maia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Male under-23 outfield football players from a Portuguese national-level team monitored across one competitive season using GPS technology during routine training sessions and official matches.

Description

Inclusion Criteria:

• Male under-23 outfield football players competing at national level and participating in regular training sessions and official matches with valid GPS data.

Exclusion Criteria:

• Goalkeepers, players with long-term injury preventing participation, or sessions with missing or invalid GPS data.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
U23 Football Players; Male under-23 football players competing at national level monitored across one competitive season using GPS technology during training sessions and matches.	Other: External Load Monitoring; Observational monitoring of locomotor demands using GPS technology during routine training sessions and matches. No experimental intervention was applied.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Counts of High-Intensity Accelerations and Decelerations (Absolute vs Normalized Thresholds)	Number of acceleration and deceleration efforts performed at high intensity using absolute thresholds (>3 m/s² and <-3 m/s²) and individualized normalized thresholds (75-100% of individual maximum) across microcycle sessions relative to match load.	Across one competitive season (approximately 10 months)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Distance Covered in High-Intensity Accelerations and Decelerations	Distance covered during high-intensity acceleration and deceleration efforts using absolute and normalized thresholds across microcycle sessions relative to match load.	Across one competitive season (approximately 10 months)
Training-to-Match Load Ratios	Ratios comparing locomotor acceleration and deceleration demands between training sessions and matches across the microcycle.	Across one competitive season (approximately 10 months)

Collaborators and Investigators

• Sponsor: University of Maia
• Investigators: Principal Investigator: Ricado Lemos Pimenta, PhD, University of Maia

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2024
• Primary Completion (Actual): July 31, 2025
• Study Completion (Actual): July 31, 2025

Study Registration Dates

• First Submitted: February 27, 2026
• First Submitted That Met QC Criteria: February 27, 2026
• First Posted (Actual): March 5, 2026

Study Record Updates

• Last Update Posted (Actual): March 5, 2026
• Last Update Submitted That Met QC Criteria: February 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Soccer; Microcycle; Acceleration; External Load; Sports Science; GPS Monitoring; Deceleration; Normalization
• Other Study ID Numbers: ACCDEC-NORM-U23-2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be publicly shared due to privacy considerations and institutional agreements with the participating football club. Aggregated data may be available from the corresponding author upon reasonable request.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No