Hi there and welcome to post 61 of Strength and Conditioning For Therapists. Forgive me, it’s been a while since my last post (t sounds like I’m about to start a confession!). Like for many, life has been hectic recently. But, I think (hope) I’m through the bulk of the hectic-ness and I’m really glad to be back on the blog. Today we’re going to answer the question: what is rate of force development?
I feel this is becoming a hot topic in rehabilitation. So much so, I was invited on to the JOSPT podcast to discuss it. Rate of force development is something that I’ve measured, evaluated and sought to train/rehabilitate throughout my career, so it’s an idea of performance I know very well.
I’m delighted to include the link to the blog below. It’s about 30 mins long.
In this podcast I talk about:
- What RFD is
- What RFD isn’t
- How to measure RFD
- Can you measure RFD in the clinic?
- How does fatigue affect RFD?
- Does exercise-induced muscle damage affect RFD?
- Is RFD important in injury avoidance?
- How do you train RFD?
I hope you enjoy it. Please let me know 🙂 As a starter, here are the basics.
Rate Of Force Development and Muscle Power
Okay, the first thing to say is that rate of force development, or RFD, is not the same as muscle power. Yup, that’s right. I know that these terms may be used interchangeably, but they’re not exactly the same.
Broadly speaking, both can be classed as the speed of muscle force production, however, RFD is typically measured in laboratory settings with instrumented dynamometry. Muscle power is typically measured with more gross tests of function, like the vertical jump, or sprint over a set distance. RFD is an important component part of muscle power.
How to Measure RFD?
Right, so this is what it might look like if you’re assessing RFD (below). We’re looking at the slope of the force-time curve obtained from an isometric contraction. This assessment is conducted under very controlled conditions with very sensitive kit.
The steeper this slope, the greater the RFD, and RFD is measured in Newtons per second (N.s-1). Often we measure the slope of different parts of the curve, like over separate 50 millisecond time intervals.
How to Measure Muscle Power?
Muscle power is probably something you’re more familiar with. And I’m sure I don’t need to tell you the basics of these assessments. Typical tests include things like vertical jump for height, horizontal jump for distance and the kit required can rage from digitised and calibrated force plates, to a tape measure.
In the podcast I explain the difference a little more in detail and the relative advantages and disadvantages of these types of measurements.
Click below, sit back and relax.