The Numbers Behind Rehab and Sport

Written By David Ding

Athletes today have wearables and GPS tracking systems to track every part of their life – walking, sleeping, eating, running, jumping, you name it. All the amazing tech that’s easily accessible today is gathering valuable data with the goal for athletes to minimise risk of injuries.

You’d think that with all this data, injuries would be dropping. But in reality, the opposite seems true: injuries are more common, and many athletes experience repeated injuries to the same joint or muscle group.

The problem? We’re great at measuring loads in sport, but we’re not matching them in rehab. Most rehabilitation protocols are still based on low-load, low-force exercises that may get you pain-free…

But nowhere near sport-ready.

Let’s break this down in numbers - this will help us understand in a quantitative manner.

No guessing, just facts.


The High Rate of Re-Tears

Re-injury statistics in major joints and tendons are alarmingly high:

  • ACL reconstructions – re-tear rates range from 10–25% within the first 2 years.

  • Achilles tendon ruptures – re-rupture rates around 8–20%.

  • Rotator cuff repairs – re-tear rates as high as 20–70% depending on tear size and follow-up length.

One major reason? Rehab exercises are simply not loading the tissues anywhere close to the forces experienced in sport.


Industry-standard protocols often stop at “safe” exercises that are great for pain reduction but woefully underpowered for performance return.


The Numbers in Sport:

Bodyweight Multiples & Force Management

Sports are brutal on the body. They demand huge, repetitive loads that your tissues need to be ready for:

  • Running/jogging: ~3–7 × bodyweight through the knees with each step.

  • Jumping/landing: ~7–15 × bodyweight through knees and Achilles on impact.

  • Badminton smaashes/baseball throws: up to 1,000–1,500 N on the shoulder rotator cuff during rapid acceleration and deceleration phases.

These aren’t occasional spikes – they happen hundreds of times in a match.


What Rehab Usually Gives You

Now compare those forces to what standard rehab exercises deliver:

  • Clamshells & crab walks (for knee rehab): ~0.5–0.8 × bodyweight load on knee joint.

  • Double-leg calf raise (Achilles rehab): ~1 × bodyweight load on Achilles tendon.

  • Single-leg calf raise: ~1.2–1.3 × bodyweight load on Achilles tendon.

  • Banded pull-aparts, prone W/Y/Ts (rotator cuff): ~0.2–0.6 N x bodyweight load on rotator cuff.

Numbers don’t lie – these are miles below what sport will throw at you.


Exercises That Match the Demands of Sport

If the sport demands high force, rehab needs to progressively get there. Effective rehab isn’t about doing “harder” exercises for the sake of it — it’s about progressively exposing tissues to the same loads they’ll face in sport.

You don’t need crazy and complicated exercises. You just need to start feeding your body, joints, and tendons the numbers they deserve. This is best achieved through intentional loading with the right exercises.

Here are a few simple ones to try at home.

  • Knees: Pistol squats (~3–4 × BW load), Split-Stance Hops (~5–8 × BW on landing).

  • Achilles: Weighted single-leg calf raises (~1.8–2.5 × BW), pogo jumps/double-leg hops (~4–6 × BW).

  • Rotator cuff: Pull-ups (~1 × BW for most athletes), side-lying external rotation with heavy load (can reach 1–4 × BW torque equivalent at the shoulder).

These exercises don’t just restore movement – they bridge the gap between clinical clearance and real-world resilience.


The Takeaway

Rehab often stops short of preparing athletes for the real world.


Sport is unforgiving — it doesn’t care that you’ve been cleared by your physio or surgeon, and it certainly doesn’t adjust its forces to match your training.

If your rehab doesn’t bridge the gap between pain-free movement and sport-level load, you’re not returning to play — you’re stepping into risk.

The solution is clear: use the numbers. Know the loads of your sport, measure the loads in your rehab, and make sure you meet or exceed them before stepping back on the field or court.

Know your numbers, use them, and minimise your risk of injuries - the right way.

Here’s a table that summarises all the numbers we’ve talked about!

forcetable
David Ding