Understanding acceleration in alpine ski racing
In alpine skiing, athletes do not generate speed in the way a runner or a cross-country skier does. There is no pushing against the ground to create forward motion. Acceleration comes almost entirely from gravity.
Performance depends on how well an athlete manages that acceleration as they move through the course. That distinction matters when reviewing runs. Video shows what an athlete did. Acceleration shows what happened as a result.
Want the short version? Acceleration helps coaches see where an athlete is accelerating, holding, or braking, inside the turn. Protern shows this directly on video and across full runs.
See how Protern works in a training day
Acceleration is about how gravity is used
In simple terms, acceleration in alpine skiing is about how effectively an athlete allows gravity to act in the direction they want to go. When an athlete moves closer to the fall line and allows the skis to run, acceleration builds. When they turn away from it, scrub pressure, or brake unintentionally, acceleration drops.
Every turn includes moments where acceleration builds, holds steady, or is reduced. Those moments are where meaningful performance differences usually appear, even when two runs look similar on video.
Why acceleration matters inside the turn
Most performance differences are not created between turns. They happen inside them.
Two athletes can take a similar line and still manage acceleration very differently. One may allow acceleration to build earlier in the turn. Another may delay it. One may carry momentum through the exit. Another may shed it while trying to regain control.
Acceleration analysis makes those differences visible. Instead of relying only on what the movement looks like, coaches can see where an athlete is accelerating, where they are holding, and where they are braking.
Related reading: Data-linked video analysis and Clear performance comparison.
Acceleration overlays in Protern Video
In Protern Video, acceleration can be shown directly on the athlete’s path through the turn. This allows coaches to see where acceleration builds and where it drops, exactly where it happens on the course. It becomes much easier to explain why a turn felt fast but did not produce the expected outcome, or why a turn that looked controlled resulted in braking.
- See acceleration changes inside the turn, not just at the end of the section
- Connect what you see on video to what happened on the snow
- Explain where braking starts, and where acceleration resumes
Comparing acceleration between two runs
Acceleration becomes even more useful when runs are compared. In side-by-side video comparison, two runs can be viewed together while also comparing how acceleration changes through the same section. This often reveals differences that are difficult to see with video alone.
One athlete may be accelerating earlier in the turn. Another may be braking slightly longer before releasing. Those differences often explain why one run carries more momentum into the next gate.
- Compare where braking begins in each run
- Compare how quickly acceleration builds after the release
- Use the same section as a shared reference during review
Related reading: Shared understanding between coach and athlete.
Acceleration across a full run in Protern Web
In Protern Web, acceleration can be reviewed across multiple runs at once. This makes it possible to see where acceleration builds and drops along the course, across an entire run, and across many runs. Coaches can identify consistent patterns, sections where athletes struggle to build momentum, or areas where braking appears repeatedly.
- Compare multiple runs to find repeatable braking points
- Spot sections where athletes fail to rebuild acceleration after the gate
- Use the course view to guide what you focus on in video review
Learn more about comparing runs
Using late-season acceleration as next season’s reference
Acceleration analysis is most valuable when it comes from meaningful runs. Late-season training and races often show athletes at their sharpest. Capturing acceleration patterns during this period provides a strong reference for comparison when the next season begins.
- Capture race data when athletes are sharp and confident
- Use late-season runs as a baseline for early-season comparison
- Carry a clear reference into the first races of next season
If you are planning ahead for next season, this is also the easiest time to start using Protern. You get value now, and you arrive at next season with a library of reference runs.
Where acceleration fits in a normal review
Acceleration analysis is not a replacement for video review. It is a way to make video explanations clearer. By linking acceleration directly to what athletes see on video, coaches can explain not just what happened, but why it happened. That shared understanding makes feedback easier to absorb and easier to apply on the next run.
Acceleration can be reviewed in three places:
- Protern Video (single athlete): acceleration shown on the path through the turn
- Protern Video (side-by-side): compare two runs to see differences in braking and acceleration
- Protern Web (full run): compare multiple runs and see where acceleration builds and drops along the course
Related reading: Data-linked video analysis, Faster feedback during training, and How Protern works.
Next step
If you want to see how acceleration overlays look with your own athletes, the fastest path is to use Protern during real training days and real races.
