This archive contains a collection of documents and studies related to the BASE System, balance measurement, and various shooting‑sports topics.

XMas at Prins Hendrik

In December 2019, the “Amersfoortse Schietsportverenging Prins Hendrik” held its annual informal Christmas match.
During this event, the BASE System was used to challenge participants to stand as still as possible.

For this experiment, the audio biofeedback of the BASE System was switched off. The platform was used purely as a measurement tool to assess postural stability in two conditions:

• Eyes open
• Eyes closed

You can read about the set-up and results of this experiment here.

Stabliogram: before BASE existed

Back in 1999, Wim Bles and I conducted a pilot study on postural control and shooting performance in air‑rifle athletes.  We took the “stabilometer" to the “Amersfoortse Schietsportverenging Prins Hendrik” to do our measurements.

We wrote our initial report on this study in Dutch –   you can find it here.  A lightly revised and translated English version (2020) is available over here.

Shot group statistics

Febr 2005

A web page dealing with questions like:

• Relationship between the shot group s.d. and the scoring distribution: how many 9-s, 8-s, etc. are reasonable to score in a match, given your mean score?
• Matching Ammo To The Rifle
• How much points do you lose due to your ammo quality, given your own performance level?
• What’s an acceptable shot group diameter when selecting pellets?

Picking the most precise ammo, probably

May 2006

Suppose you have two batches of pellets and you want to decide which one is the best for your competition shooting. These pages covers three issues.

• From several known measures for shot group tightness measures, which one is the most often correct when you are trying to identify the best batch (no matter how small the difference).
• What is the best way to spend a given number if shots: all in 1 group, or several sub-groups?
• Using a statistical test to find out if the differences between two batches are statistically significant.

Adding pressure to air rifle training

A practical idea on how to apply some psychological pressure during training sessions

Don’t even THINK about shooting an 8

Cant angle

• Here you can read where, why, and how far the point of impact moves due to canting the rifle. This is discussed using a simple theory, supported with calculations from PCB.
• Here you can read about a test that was conducted to verify this theory and PCB’s calculations with respect to the cant angle effect.
• Here you can read about a test that was conducted to verify this theory and PCB’s calculations with respect to the line of sight height (riser blocks)

PCB (PC Ballistics)