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Predicting Session External Load: Performance Data & GPS Analysis
- Enrico Mordillo
- 6 days ago
- 5 min read
From Data Collection to Performance Prediction
Welcome to the fourth installment of our series on GPS data in football. In this post, we explore one of the most sophisticated aspects of sport science: predicting and estimating the external load for both a single session and an entire weekly microcycle.
While most content online focuses on analyzing what happened after training, this guide shifts the focus to the future. By learning how to estimate load, you can design training sessions with a precise "physical target" in mind, ensuring your periodization is truly data-driven.
Watch the Guide: Step-by-Step Load Estimation
In the video below, I dive into a topic rarely discussed in detail on the web. I provide a step-by-step tutorial on how to use historical GPS data and drill constraints to forecast the external load.
What you will learn in this video:
How to establish "standard" intensity values for your drills.
The impact of pitch dimensions (Area per Player) on predicted output.
How to build a predictive model for a full weekly microcycle.
The Three Pillars of GPS Data Analysis
To maximize the impact of GPS technology in professional football, I categorize the analysis process into three distinct and critical phases. Each phase serves a specific purpose in the performance-optimization cycle:
Phase 1: External Load Estimation (Forecasting)
Scope: Single Drill – Training Session – Weekly Microcycle.
Objective: This is the "pre-pitch" phase. Based on historical data and the specific constraints of the session (Area per Player, duration, rules), we estimate the expected physical output. This allows the coaching staff to align the training design with the tactical and physical objectives of the day.
Phase 2: LIVE Analysis (Real-Time Monitoring)
Scope: In-session monitoring.
Objective: During the training session, real-time analysis allows us to verify if the players are hitting the predicted targets. If a drill is significantly over or under the estimated intensity, the S&C coach can provide immediate feedback to the head coach to adjust dimensions, duration, or rest periods on the fly.
Phase 3: Post-Session Analysis (Reporting & Evaluation)
Scope: Retrospective analysis.
Objective: Once the session is concluded, we conduct a deep dive into the data to quantify the actual external load. This phase is crucial for assessing the "Work Done" vs. "Work Planned," managing individual recovery protocols, and updating the historical database to refine future Phase 1 estimations.
Phase 1: Estimating External Load
Today we focus on the first phase of the workflow. Although it sits at the beginning of the planning cycle, it "hypothetically" occurs after post-training analysis, as it requires a robust database built from actual on-field performance metrics.
In the video, I demonstrate the process of estimation—a term I prefer over "prediction," as we lack the mathematical certainty that the exact values will be replicated during the session. We will explore how to estimate load in three different contexts:
Session External Load Estimation (Team): How to select various training drills and compile them to estimate the total physical parameters of a full session.
Weekly Microcycle Estimation (Team): Calculating the cumulative external load of an entire work week by sequencing the estimated sessions designed during the planning phase.
Individualization of the Estimation Process: Moving beyond team averages to introduce load estimation tailored to specific roles or individual player profiles.
The first and most critical step is creating a solid database built from EFFECTIVE analyses of various drills executed on the pitch. It is crucial not to use "Global" session analyses, as the inclusion of rest periods would dilute the metrics and skew the results.
To obtain a clear picture of the actual intensity, we must isolate the effective work time for each drill.
Data Normalization: The "Per Minute" Approach
Once we have extracted the data from our previous analyses, we need to normalize it. This means converting all metrics into relative values per minute (e.g., m/min, ACC/min).
By doing this, we can transform these values into functions of time, allowing us to accurately estimate the load regardless of the duration we choose to set for future sessions.
The Solution: Automating the Process with Excel
So, how can we estimate the external load simply and automatically?
I have developed a dedicated Excel tool designed for this exact purpose. Using a "Combo Box" (drop-down menu), I can select specific drills from my archive. Once the drill is selected, I simply input the training protocol (number of sets and their duration), and the system automatically calculates the estimated load. It's that simple!
From Data to Insights: The Session Report
Once each "puzzle piece" of the session is selected, the tool automatically generates a comprehensive Performance Report (see images below), providing an estimation of the entire training day.
To make the data actionable, I have integrated two key analytical features:
1. Drill Profiling via Scatter Plots
I use a scatter plot to visualize the profile of every single drill. This allow us to immediately identify the specific impact on the players:
Metabolic-driven drills: High energy cost and metabolic power.
Neuromuscular-driven drills: High frequency of accelerations, decelerations, and changes of direction (CoD). This visual mapping ensures that the session's physical theme aligns with the tactical periodization.
2. Immediate Feedback with Z-Scores
To evaluate how much the estimated parameters deviate from the team's "normal" or "average" loads, I utilize Z-Scores. This provides an instant visual feedback:
It highlights whether a parameter is being over-stimulated or under-replicated compared to the historical baseline.
It helps in maintaining the correct balance throughout the microcycle, preventing unwanted spikes in load.
Beyond the Single Session: Estimating the Weekly Microcycle
Up to this point, the process is relatively straightforward. But what if we want to go further? What if we want to estimate an entire weekly microcycle?
Using the same Excel tool I developed, this is not only possible but highly efficient. By following the same procedure—inputting each drill that composes the various sessions of the week—you can obtain a comprehensive overview of the total weekly workload.
Why Microcycle Estimation Matters
Having this data at your fingertips allows you to "see further ahead" in time. Specifically, it enables you to:
Monitor Load Variability: Understand the fluctuations in intensity and volume between different microcycles.
Match Performance Benchmarking: By entering data for each individual session, the tool generates a detailed report that compares the estimated external load against the Match Performance Model.
Informed Modulation: This comparison tells us immediately if the workload is sufficient, excessive, or if we need to modulate specific variables to reach our peak performance goals.
Final Considerations
Personally, I believe that estimating the load of a session or a microcycle is an invaluable asset for minimizing errors on the pitch. However, we must always remember that this remains an "estimation" and should be approached with the necessary professional caution.
For GPS analysis to be truly effective—and not just an exercise in data collection—a collaborative team effort is essential. It requires a synergy between the Sport Scientist's analysis and the Head Coach's execution on the field. Without a precise and high-quality data management process, we are simply looking at numbers that tell us nothing.
In the video, I focused on team-level load estimation. Depending on your professional context, this process can be further refined: from analyzing specific units (defense, midfield, attack) to individualizing the estimation for each player, ensuring that every athlete receives the exact stimulus they need.
Click the link below to download my Excel tool for External Load Estimation and start optimizing your microcycles today! - Predict Training Load Program Excel File
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