Speed Matters: Unlocking Rate of Force Development in Rehab

rangeptmontana
Jun 17
2 min read

Written by Brenna McGuinness, DPT

When it comes to athletic performance and rehabilitation, how quickly you produce force can be just as important as how much force you produce. This is where Rate of Force Development (RFD) comes into play — a key metric that helps us understand explosive strength and neuromuscular function.

What is RFD?

RFD is a measure of how fast an individual can generate force — essentially, how quickly your muscles can “turn on” and produce power. In rehab and performance settings, this matters because real-world movements (like jumping, cutting, or reacting to a fall) don’t happen slowly — they require rapid force.

Why Do We Measure It?

Injury, surgery, or deconditioning can impair RFD, even when total strength appears to return. This can leave patients vulnerable to re-injury or reduced performance. By measuring RFD, clinicians can:

Monitor explosive strength recovery after injury (e.g., ACL reconstruction)
Identify asymmetries or deficits not obvious with peak-force tests
Tailor rehab programs to restore power, not just peak strength

How We Measure RFD with My Jump 2

The My Jump 2 app is a validated and accessible way to measure jump height and calculate metrics like RFD using slow-motion video. It works like this:

The athlete performs a jump test.
Using a high-frame-rate camera (often just an iPhone), the app analyzes the takeoff and landing frames.
From this, the app calculates flight time, jump height, and power outputs — which we can use to estimate RFD.

It’s a practical way to monitor progress over time and ensure that rehab includes a return to high-speed capacity — not just strength under slow load.

Who Is It For?

Post-op patients (e.g., ACL, Achilles, hip labral repairs)
Athletes returning to sport
Older adults working on fall prevention and reactive strength
Anyone rehabbing from injury with a goal to return to dynamic, explosive movement

IN SHORT: RFD matters. And with tools like My Jump 2, we can measure what matters — helping people get back to their goals faster, stronger, and safer.