Does four weeks of daily, actually-completed dorsiflexion work move my injured ankle's knee-to-wall distance by more than 1 cm?
+3.4 cm on the injured side, +0.2 cm on the control side. Objective, boring, and the best data in this series.
Dates
Sep 29 – Nov 03, 2025
Duration
4 weeks + baseline
Pre-registered primary
Knee-to-wall distance, left ankle (cm)
FN-04 · 01
The question
The August lateral sprain was my second on the left ankle, and it came with the usual prescription: a daily dorsiflexion routine from my physical therapist, the kind of homework that every PT knows is where rehab actually dies. Sophomore me ran the low-compliance arm of this study on the first sprain, unregistered, and the results were bad. This time I did the opposite: total compliance, plus measurement.
To be precise about what is being tested, because it matters: the protocol here is my PT's, not mine. I did not invent a rehab program, and this module never will. The experiment is narrower and more honest: if the prescribed work is actually done, every day, does the stiffest measurement I own move? Falsifiable form: knee-to-wall distance on the injured left ankle improves by more than 1 cm in four weeks, with the right ankle measured identically as a drift detector.
FN-04 · 02
Pre-registration
- Protocol
- The PT-prescribed routine, 10 minutes daily: half-kneeling weighted knee-to-wall rocks, banded talocrural mobilizations, and full-range calf raises, exactly as prescribed. Nothing added, nothing skipped, nothing progressed without her say-so.
- Duration
- Four weeks, starting Oct 06. Measurements Monday and Thursday mornings, plus the three baseline sessions already logged.
- Primary outcome
- Knee-to-wall distance, left ankle: big toe to wall in cm with the knee touching the wall and the heel down, average of three trials, tape measure fixed to the floor for the entire study.
- Secondary outcomes
- Right (uninjured) ankle, same protocol, as a control limb
- Single-leg balance time, eyes closed, seconds
- Counts as null
- Left-ankle gain under 1 cm is a null. Separately: if the right ankle 'improves' by a similar amount, the left gain is reclassified as measurement drift regardless of its size. The control limb outranks my enthusiasm.
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-04 · 03
The protocol
Compliance: 26 of 28 days, with the two misses logged (a tournament Saturday and a night I simply forgot, which goes in the record because pretending I am a robot would defeat the purpose). Ten minutes, every day, mostly while watching film.
Measurement is the part I am actually proud of. A tape measure taped to the floor and left there for five weeks, a wall that does not move, the same bare-foot setup, three trials per ankle averaged, both ankles every session. Knee-to-wall is brutally simple: slide the foot back until the knee can only just touch the wall with the heel down, read the centimeters. No rating, no opinion, no vibe. The tape does not care how optimistic I am.
Compliance
26/28days
Daily dose
10min
Measurements
11sessions
Trials averaged
3per ankle
FN-04 · 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.
The flat gray line is the whole argument: if the left-ankle gain were technique drift or tape creep, the right ankle would show it too. It shows 0.2 cm, inside trial-to-trial spread.
›View the raw log · 11 rows
| measurement session | Date | Phase | Left (injured) (cm) | Right (control limb) (cm) |
|---|---|---|---|---|
| 1 | Sep 29 | baseline | 6.1 | 10.4 |
| 2 | Oct 02 | baseline | 5.9 | 10.6 |
| 3 | Oct 05 | baseline | 6 | 10.5 |
| 4 | Oct 09 | intervention | 6.3 | 10.5 |
| 5 | Oct 13 | intervention | 6.8 | 10.4 |
| 6 | Oct 16 | intervention | 7.2 | 10.6 |
| 7 | Oct 20 | intervention | 7.7 | 10.7 |
| 8 | Oct 23 | intervention | 8.3 | 10.5 |
| 9 | Oct 27 | intervention | 8.7 | 10.6 |
| 10 | Oct 30 | intervention | 9.1 | 10.8 |
| 11 | Nov 03 | intervention | 9.4 | 10.7 |
FN-04 · 05
What happened
Left, baseline
6.0cm
Left, final
9.4cm
Left gain
+3.4cm
Right drift
+0.2cm
Left ankle: baseline mean 6.0 cm, final measurement 9.4 cm, a gain of 3.4 cm against a bar of 1.0. The trajectory is almost embarrassingly clean: roughly 0.8 to 0.9 cm per week, near-linear, no plateau yet at four weeks. The right ankle went from a 10.5 cm baseline to 10.7, a 0.2 cm drift that sits comfortably inside trial-to-trial spread. The drift detector says the tape did not move and my technique did not quietly improve; the injured ankle did.
The side-to-side gap, which is what my PT actually watches, closed from 4.5 cm to 1.3 cm in four weeks. She looked at the graph and said 'huh,' which I am choosing to log as peer review.
What made this entry feel different from every other one in the series is that there was nothing to argue with. No expectation debate, no scale steps, no wondering whether I wanted it too much. Centimeters against a wall, read off a tape, with a built-in control limb. After three experiments about feelings, measuring something was a physical relief.
The tape measure does not care how optimistic I am. That is the entire reason to own one.
FN-04 · 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.
01
Time is a confound with a healing injury
I was eight to ten weeks post-sprain. Capsular stiffness improves with natural history alone, so some unknown fraction of 3.4 cm would have arrived with no routine at all. The control limb detects measurement drift; it cannot detect healing, because it was never injured.
02
No counterfactual limb for compliance
The honest comparison is this ankle with the routine versus this ankle without, and that experiment is unrunnable. Sophomore me's sloppy-compliance sprain is suggestive, but that is an anecdote wearing a lab coat, and it involved a different sprain in a different year.
03
Knee-to-wall is a composite
Capsule mobility, soleus extensibility, residual swelling, and end-range pain tolerance all feed one number. The number moved; which tissue moved is invisible to this measurement. Notably, end-range pain fell across the month, and less pain alone yields more centimeters.
04
Tester, subject, and believer in one body
By week four I wanted the line to keep climbing, and knee-to-wall has a 'push a little harder' margin. Averaging three trials and fixing the tape reduces this; it does not remove it. A control limb helps only if I lean on both ankles with equal hope, which I cannot verify.
05
The control limb is not fully independent
Cross-education effects (training one limb slightly affecting the other) are real, though small for mobility work. If anything this biases the right ankle upward, which would make the left-right contrast conservative, but it belongs on the list.
FN-04 · 07
What I would do differently
- 01Film every trial from a fixed phone mount and re-read the distances from stills after the study, blind to session order.
- 02Have someone else read the tape at least once a week, so the study's most enthusiastic participant is not also its only instrument reader.
- 03Add figure-8 girth measurement each session to separate residual swelling from actual mobility change.
- 04In a non-rehab context, insert a deliberate week off mid-study: if the line flattens and resumes with the routine, causality firms up considerably. I did not do this here because pausing prescribed rehab to satisfy my inner methodologist is exactly backwards.
FN-04 · 08
The verdict
The verdict, for me
EffectEffect, and the one result in this series I would defend at a dinner table. The bar was 1 cm; the gain was 3.4 with a flat control limb and an objective instrument. I cannot cleanly split the credit between the routine and eight weeks of biology, and I do not need to: the ankle I land on dorsiflexes like an ankle again, and the marginal cost was ten minutes a day.
The non-verdict, for you
Your rehab belongs to your PT, not to this website, and the routine above is reproduced as a compliance story, not a program. If your ankle is the problem, the Coach's first answer will be the same as mine: get assessed by a human.
What transfers is the method: a tape line on the floor and two mornings a week turn 'I think it is getting better' into a number with a slope. Rehab compliance is miserable precisely because progress is invisible day to day. Make it visible and the whole psychology inverts.
FN-04 · Cross-references
Where this entry leads
The group evidence, the mechanism, and the instruments behind this experiment live in the other modules.
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.