Almost every lower-limb injury changes the way you walk. Sometimes the change is obvious — a visible limp, a hand resting on the counter for balance. More often it's subtle: a quarter-second less weight on one side, a step length that's three centimetres shorter on the left, a cadence dropped from 116 to 102. Those small differences are usually the signal of where recovery actually is, separate from how it feels.
This is the hub article in a series. Each subsequent piece will drill into one injury type and what the numbers do across weeks and months. The point of starting at the top: most readers' first question isn't "what specifically happens after ACL?" — it's "what should I be paying attention to at all?" Here's that grounding piece.
The five numbers that matter most
Across every gait-affecting injury we've worked with, five report metrics carry most of the recovery signal. Three of them you can feel changing on a good day; two of them you can't, and that's why measuring them is the point.
- Walking velocity — your average speed. The single most clinically meaningful number. Healthy adults walk at ~1.2–1.4 m/s; recovery from most lower-limb surgery shows velocity climbing in steps as confidence returns.
- Cadence — steps per minute. People drop cadence to feel safer. As pain and uncertainty fade, cadence climbs back toward your pre-injury baseline.
- Stride length — distance per stride. Surgery and joint pain shorten the affected-side step; symmetry returns weeks later than people report it has.
- Single-support time, per side — how long you spend balancing on one foot. The clearest "I trust this leg" signal. Compare left vs right week-over-week.
- Asymmetry index — a roll-up of the above into one number. Useful for sharing with a physio: "It's gone from 9% to 3%" is more legible than ten line charts.
Each one is defined in the glossary with a healthy-adult range and what an unusual reading typically means. Bookmark it — the reports use these words a lot.
How recovery moves through the metrics
The order in which numbers improve is fairly consistent across injuries:
- Cadence recovers first, often within weeks. You feel safer, you walk faster, the steps-per-minute climbs.
- Stride length on the unaffected side recovers next. The "good" leg starts pushing off properly again.
- Single-support time on the affected side follows — usually weeks behind cadence. This is when patients say "it finally feels like my leg again."
- Asymmetry index trails everything else by another few weeks. By the time the asymmetry rolls into the "healthy" range, the recovery is real, not a momentum effect.
Common gait-affecting injuries — a primer
Each of these will get a deep-dive post in the coming weeks. The summaries below sketch what to expect; the linked future articles will go into typical timelines, common plateaus, and the specific patterns that show up on the ReWalk report.
ACL reconstruction
The standard pattern: stride length on the affected side stays short for 8–12 weeks while you protect the joint. Single-support time on the surgical leg often takes 4–6 months to fully match the other side. Cadence comes back early but misleadingly — feeling fast doesn't mean symmetric.
Future article: "ACL Reconstruction: Walking Patterns to Watch from Week 1 to Month 12"
Total knee replacement (TKR)
Range of motion is the headline metric here — knee flexion and extension recover on a timeline that's mostly determined by how aggressive the physiotherapy is. Stance phase on the affected leg often runs short for the first six weeks because full extension still hurts at the end of stance.
Future article: "Total Knee Replacement: When Does Your Gait Normalize?"
Hip replacement (THR)
Pelvic tilt and step length asymmetry are the two metrics most surgeons want to see normalise. Trendelenburg patterns (a contralateral hip drop during single-support) often show up in the data for weeks longer than they're visible to the naked eye.
Future article: "Hip Replacement Recovery: 6 Weeks, 6 Months, 6 Years"
Ankle sprain
The most under-measured injury in the list. Most people stop thinking about an ankle sprain weeks before their gait fully normalises. Foot clearance on the affected side often stays slightly low (a clue that the ankle isn't dorsiflexing confidently) for months after the swelling is gone.
Future article: "Ankle Sprain Recovery: Tracking the Limp You Can't See"
Achilles repair
Toe-off power is the headline. Without a properly recovering Achilles, you don't push off the trailing foot fully — cadence stays low, stride length stays short. The signal in the report is usually a long-lasting single-support deficit on the surgical side.
Future article: "Achilles Tendon Repair: Why Toe-Off Takes So Long to Come Back"
Stroke / hemiparesis
The most complex case — every metric is informative because the recovery is non-linear and asymmetric by definition. Patients and physios both benefit from charting velocity and asymmetry over months rather than days; the day-to-day signal is noisy but the trend is clear.
Future article: "Stroke Recovery: What Six Months of Gait Data Reveals"
Foot drop / common peroneal nerve injury
Foot clearance crashes; toe-strike often replaces heel-strike on the affected side. With or without an AFO brace, the report tells you exactly how much compensatory hip-hike is happening as the affected leg swings through.
Future article: "Foot Drop and Gait: What the Numbers Say with and without a Brace"
How home gait monitoring fits in
The pattern that's universal: rehabilitation doesn't happen in the clinic — it happens between clinic visits. Without measurement, what gets shared back is the patient's memory of the last fortnight ("I think it's better"), which is the noisiest possible data source. With measurement, what gets shared is the line chart.
ReWalk turns the phone you already carry into a capture device. Strap it to your back, walk for a minute, get every metric in this article computed automatically. Trends roll up weekly; PDF reports go to your physio or GP with one tap. There's a 14-day free trial on every paid plan, and a forever- free tier for occasional use. See the plans page for what's included.
Track your own gait recovery from home.
Set up takes under five minutes. The first assessment captures a baseline you'll compare every future session to.
See the device appWhat comes next in this series
Over the coming weeks each of the injury sections above gets a dedicated post that goes deeper into typical timelines, what the five-number recovery story looks like for that specific diagnosis, and the patterns the physios we work with watch for. Subscribe via info@rewalk.life if you'd like the next one in your inbox.