FN-05Field note 5 of 6 · Foam rolling: the null

Does eight minutes of pre-practice foam rolling, daily for three weeks, lower my next-morning soreness by at least 0.5 points?

Baseline 4.10, rolling 4.12. My flexibility improved for about an hour. My headline did not.

Null

Dates

Nov 03 – Dec 03, 2025

Duration

31 days

Pre-registered primary

Next-morning soreness (0–10)

FN-05 · 01

The question

Foam rolling is the most defaulted-to recovery ritual in my gym: the roller sits by the door, and rolling on it feels productive in a way that is difficult to argue with. The mechanism stories attached to it, breaking adhesions, releasing fascia, are mostly not physically plausible at the pressures a bodyweight roller produces; the Library piece runs those numbers. But 'the story is wrong' is not the same claim as 'the practice does nothing,' and the second claim is testable on me.

Falsifiable form: eight minutes of rolling before every practice for three weeks, and my next-morning soreness has to drop at least half a point against a ten-day baseline. Soreness, not flexibility. That distinction is about to become the entire entry.

FN-05 · 02

Pre-registration

Pre-registration · sealed recordLocked Nov 02, 2025 · 21:26, before the first baseline day

Protocol: 8 minutes before every practice: quads, calves, glutes, thoracic spine, 60 to 90 seconds per region per side, moderate pressure (uncomfortable, not heroic). On no-practice days, same routine in the morning.
Duration: 10-day no-rolling baseline, then 21 consecutive days of rolling.
Primary outcome: Next-morning soreness, 0 to 10 in half-point steps, rated before getting out of bed, same instrument as FN-03.
Secondary outcomes: Acute sit-and-reach change, cm, measured immediately before and after each rolling session
Sit-and-reach re-test 60 minutes later, spot-checked on five sessions
Counts as null: Soreness change under 0.5 points is a null, published as a null, with the null in the title. If a secondary outcome moves, it stays a secondary. I am writing this sentence now because I can already feel the temptation coming: rolling feels productive, and if soreness does not move I will want to say 'but I felt looser.' Looseness is listed above, in the secondary slot, where it will remain regardless of what it shows.

Saved as a dated, unedited note before day one. The goalposts above are the goalposts the data was judged against; nothing in this record was touched after the first measurement.

FN-05 · 03

The protocol

Twenty-one days of rolling, zero missed sessions, because eight minutes is not a heroic ask. Baseline first: ten days of normal practice with no rolling at all, soreness logged every morning to establish what my legs do on their own.

The sit-and-reach measurements bracketed every rolling session: sit, reach, mark, roll for eight minutes, sit, reach, mark again. On five sessions spread across the three weeks I re-tested a third time, 60 minutes later, to ask how long whatever-this-is lasts. Cheap instrumentation, but consistent: same box, same shoes off, same no-bouncing rule.

Session dose

8min

Compliance

21/21sessions

Baseline

10days

ROM brackets

21pre/post pairs

FN-05 · 04

The log

The actual daily data, charted with the intervention window shaded, plus the raw log as a table under each chart. Same arrays feed both, so they cannot disagree.

Primary outcomeNext-morning soreness, daily0–10 scale

The two dashed means differ by 0.02 points. At this resolution they are the same line, which is the finding.

›View the raw log · 31 rows

Next-morning soreness, daily, in 0–10 scale. Full daily log.
study day	Date	Phase	Soreness (0–10 scale)
1	Nov 03	baseline	4
2	Nov 04	baseline	4.5
3	Nov 05	baseline	3.5
4	Nov 06	baseline	4
5	Nov 07	baseline	4.5
6	Nov 08	baseline	4
7	Nov 09	baseline	3.5
8	Nov 10	baseline	4.5
9	Nov 11	baseline	4
10	Nov 12	baseline	4.5
11	Nov 13	intervention	4.5
12	Nov 14	intervention	4
13	Nov 15	intervention	4
14	Nov 16	intervention	4.5
15	Nov 17	intervention	3.5
16	Nov 18	intervention	4
17	Nov 19	intervention	4.5
18	Nov 20	intervention	4
19	Nov 21	intervention	4.5
20	Nov 22	intervention	4
21	Nov 23	intervention	3.5
22	Nov 24	intervention	4.5
23	Nov 25	intervention	4
24	Nov 26	intervention	4
25	Nov 27	intervention	4.5
26	Nov 28	intervention	4
27	Nov 29	intervention	4.5
28	Nov 30	intervention	3.5
29	Dec 01	intervention	4
30	Dec 02	intervention	4.5
31	Dec 03	intervention	4

SecondaryAcute sit-and-reach change per session (secondary)cm (post − pre)

Every session, without exception, immediate range of motion improved. The five 60-minute re-tests averaged +0.4 cm: it evaporates within the hour. This stayed a secondary outcome, per the sealed record.

›View the raw log · 21 rows

Acute sit-and-reach change per session (secondary), in cm (post − pre). Full daily log.
rolling session	Date	Phase	Post-roll gain (cm (post − pre))
1	Nov 13	intervention	2.5
2	Nov 14	intervention	3
3	Nov 15	intervention	2
4	Nov 16	intervention	2.5
5	Nov 17	intervention	3.5
6	Nov 18	intervention	2.5
7	Nov 19	intervention	3
8	Nov 20	intervention	2
9	Nov 21	intervention	2.5
10	Nov 22	intervention	3
11	Nov 23	intervention	2.5
12	Nov 24	intervention	2
13	Nov 25	intervention	3
14	Nov 26	intervention	2.5
15	Nov 27	intervention	3.5
16	Nov 28	intervention	2.5
17	Nov 29	intervention	2
18	Nov 30	intervention	3
19	Dec 01	intervention	2.5
20	Dec 02	intervention	3
21	Dec 03	intervention	2.5

FN-05 · 05

What happened

Soreness, baseline

4.10/ 10

Soreness, rolling

4.12/ 10

Primary delta

+0.02pts

Acute ROM (2°)

+2.6cm

The primary outcome: baseline soreness averaged 4.10 over ten days; soreness during three weeks of daily rolling averaged 4.12. The difference is 0.02 points, which is not merely under the 0.5 bar, it is as null as this instrument is physically capable of expressing. The ranges are identical: 3.5 to 4.5 in both phases. Twenty-one consecutive days of dutiful rolling produced next-morning legs that were indistinguishable, to the limit of my measurement, from the legs that got no rolling at all.

The secondary outcome moved, and moved every single time. Immediate sit-and-reach improved by a mean of 2.6 cm after every one of 21 sessions, range 2.0 to 3.5, without a single exception. That is a real, repeatable, honest little effect, and it is consistent with what the literature says short-term rolling does: a transient increase in range of motion, probably neural in origin, an acute change in stretch tolerance rather than any mechanical change in the tissue. The 60-minute re-tests averaged +0.4 cm. It is gone within the hour, like the smell of rain.

Now the trap this entry exists to demonstrate. If I had not pre-registered, I would right now be writing a headline about how foam rolling works: plus 2.6 centimeters! Every session! Consistency you could set a watch by! And I would quietly have forgotten that the question I actually asked, the one I cared about enough to spend a month on, was about soreness. That move is not exactly lying. It has a name: outcome switching. It is how half the recovery industry writes its copy, and the only thing that stood between me and doing it accidentally is a sealed paragraph written on November 2 by a version of me who did not yet know the answer.

The sealed record is the only thing standing between me and a better-sounding result.

FN-05 · 06 · Mandatory in every entry

Why this is weak evidence

This section is the module’s actual thesis. The result above is the least important thing on this page; the list below is why.

A null is not a proof of nothing

This entry's headline claim needs the same skepticism as any effect would. My instrument (a half-point subjective scale, n of 1, 21 days) could miss a small true benefit. I can roughly bound it: an average effect much larger than half a point over three weeks would probably have surfaced; anything smaller, I am blind to. 'Nothing detectable by me' is the claim. 'Nothing' is not.

Dose is one point in a large space

Eight minutes at moderate pressure is one protocol. Heavier pressure, longer durations, post-practice instead of pre-practice timing: all untested here. The null covers my protocol, not the roller.

Sequencing, again

Baseline first, intervention second, no randomization: the standard weakness of every before-and-after design in this series. It cuts differently for a null, though: expectation was pushing toward an effect, the design was tilted toward finding one, and none appeared anyway. A biased search that comes home empty is modestly reassuring in reverse.

Floor effects

My soreness averaged a mild 4 all month; this was a normal training block, not a brutal one. Rolling might genuinely help at a soreness of 7 after a tournament. This study cannot see that from where it stood.

Expectation can suppress as well as inflate

By week two I suspected the null and had started composing this write-up in my head. In principle that could bias ratings downward-toward-boring. The direction of my original expectation argues against it mattering here, but symmetric honesty requires the line.

FN-05 · 07

What I would do differently

01Alternate rolling and no-rolling days FN-03 style, so both conditions sample the same training weeks instead of adjacent months.
02Run it across a deliberately heavy block, where soreness has headroom to fall and a real effect would have room to show itself.
03Add a pressure-pain threshold measurement with a cheap algometer: an objective, quantitative soreness proxy instead of a morning opinion.
04Blind the sit-and-reach reads: a friend records where my fingers land and tells me nothing until the study closes. My secondary deserved better instrumentation than my own eyes at close range.

FN-05 · 08

The verdict

The verdict, for me

Null

Null on the question I actually asked, and the proudest result in this series precisely because publishing it stings a little. I still roll sometimes before practice, and I can even defend it honestly: two and a half centimeters of range for an hour is a real, small, useful thing right before a session that needs the range. What I stopped doing is calling it recovery, because for me, measurably, it is not.

The non-verdict, for you

The transferable part of this entry has nothing to do with foam. It is that the question you write down before you start is the only question you get to answer. Everything interesting you notice along the way, and you will notice things, goes back into the hypothesis pile for the next experiment. That rule feels pedantic right up until the day it is the only thing keeping your headline honest.

Previous · FN-04The ankle projectOpen Next · FN-06Tart cherry, in real lifeOpen

FN-05 · Cross-references

Where this entry leads

The group evidence, the mechanism, and the instruments behind this experiment live in the other modules.

Truth Engine · TEThe foam rolling audit: fascia does not work that wayOpen Science Library · SLWhy range of motion changes in minutes: stretch toleranceOpen

Education, not diagnosis. This is a student-authored science platform. Nothing here replaces a physician, a physical therapist, or an athletic trainer. Sudden severe pain, numbness, an inability to bear weight, or visible deformity means stop reading and get seen.