What External Load Alone Misses: 5 Examples from Pro Performance Staff

In this article, performance professionals across elite sports teams give 5 examples of why you shouldn’t rely on external load data alone and how combining it with internal load data influences coaching decisions.

A Mountain of Data – But What to Do With It?

For many pro teams, the challenge is not collecting data; it’s making sense of it. GPS systems, athlete tracking technologies, and wellness monitoring tools generate more information than ever before.

Yet despite this abundance of data, coaches are often left with the same question: what should we actually do with it?

The real competitive advantage doesn’t come from having more data. It comes from turning data into better decisions, understanding how internal and external load interact, and using that connection to guide daily coaching decisions.

As Alexi Pianosi, Head of Strength & Conditioning for the Colorado Avalanche, puts it:

“I don’t want the data to give me answers. I want it to ask better questions.”

That mindset is what separates monitoring from decision‑making.

Why Coaches Need to Monitor Both Internal and External Load

External load describes what the athlete does:

• Distance covered
• High‑speed running or skating
• Accelerations and decelerations
• Time on ice or minutes played

These metrics are essential for understanding exposure to physical demands.

But they don’t explain how hard that work was for the athlete.

Internal load shows the cost of the work and how the body responds:

• Heart rate response
• Time spent at high physiological intensity
• TRIMP and TRIMP per minute
• Subjective perception of effort

As Georgia Brown (San Diego Wave FC) explained during our women’s soccer panel:

“Two players can complete the same session with the same external load, and one may experience it as a very hard session while the other does not.”

Without monitoring internal load, coaches can be unaware of these individual differences, relying only on subjective feedback from the athletes and guesswork.

Let’s take a look at some case studies where combining both external and internal load influenced real coaching decisions.

Example 1: Differences in Max Heart Rates in Small-Sided Games

During small‑sided games, a women’s professional soccer team observed fairly even GPS outputs across the squad. Distance, speed, and work rate appeared consistent.

However, heart rate monitoring told a different story.

Some players spent large portions of the session above 90% of their maximum heart rate, while others accumulated far less internal load from the same drills.

The coaching decision that followed:

Instead of treating the group uniformly:

• Rest intervals were adjusted for certain players
• Exposure to repeated bouts was reduced for others
• Some athletes were progressed, while others were protected

Georgia notes: “Internal load helped us adapt sessions, so we weren’t killing new players just because the session looked fine on GPS.”

This decision would not have been made from looking at external load alone.

Example 2: Returning to Play Too Quickly

In rehabilitation settings, athletes often regain movement quality before full physiological readiness.

Dr. Nicole Surdyka (Physical Therapist & Sports Scientist) describes how internal load plays a critical role here: “Whilst the injured tissue might be coping, the cardiovascular system and nervous system often lag behind.”

In several return‑to‑play cases, Nicole noticed that heart rate responses for injured players during reintegration drills remained elevated compared to pre‑injury baselines, even though the external outputs looked ok.

The coaching decision that followed:

Instead of accelerating match exposure:

• Conditioning intensity was temporarily reduced
• Additional recovery was added mid‑week
• Full match minutes were delayed by one microcycle

This resulted in successful player returns without further setbacks.

Example 3: Why External Load Alone Falls Short in Ice Hockey

The previous two case studies give examples of why you should combine internal and external load data in soccer, but what about in other sports, like ice hockey?

During our NHL webinar, Alexi Pianosi explained how two defensemen with similar minutes and roles can accumulate vastly different internal loads due to:

• Playing style
• Physical contact
• Skating efficiency
• Tactical responsibilities

In one example, Alexi explains that when two defensemen played similar minutes against the same opponent:

• One accumulated a significant red‑zone heart rate time
• The other spent almost no time in the red zone

Both players were effective and helped the team win, but both showed very different responses that would have been difficult to see by looking only at external load.

Pianosi emphasizes the importance of looking at each individual’s response. “You have to evaluate players relative to themselves, not each other.”

Example 4: Goalies and Hidden Load

Goalkeepers offer another reminder of why monitoring internal load matters.

Despite minimal external movement, NHL goalies often accumulate very high physiological strain across games due to:

• Sustained sympathetic activation
• Reaction‑based stress
• Long periods at an elevated heart rate

As Alexi explains: “A goalie’s aerobic system is constantly engaged, even when they aren’t moving much.”

Without looking at internal load, this stress would be largely invisible.

Example 5: Tracking Adaptation with Submaximal Testing

Another way to connect internal and external load is through submaximal fitness testing.

By standardizing the external load (for example, a four‑minute continuous effort at a fixed speed), coaches can track how internal load changes over time:

• A lower heart rate for the same work suggests improved fitness
• A higher heart rate response may indicate fatigue or incomplete recovery

During a recent Firstbeat webinar, Philipp Lussi from TSG 1899 Hoffenheim gave an example of how he used submaximal testing to build stories around player data over a season:

“I saw a player’s heart rate in the preseason and at the beginning of the season, more or less going down in the right direction the whole season. You can confirm, OK, the training adaptation is good, fitness is going in a good direction.”

By using repeat submaximal testing over time, coaches can easily monitor changes in cardiovascular fitness and continually review and evaluate whether any adjustments are required to training, either on a group level or individually.

Understanding the Bigger Picture

Across team sports and rehabilitation settings, the message is clear: performance data is most valuable when internal and external load are viewed together.

External load shows what athletes did. Internal load shows how they responded. Connecting the two provides the context needed to make smarter training, recovery, and return-to-play decisions.

As Alexi Pianosi summarizes:

“The goal isn’t more data. It’s better decisions.”

And that is what connecting the dots is really about.

Download our free training load guide for strength and conditioning coaches to learn more about internal load metrics and how they can help support your coaching decisions.