The Workout: SFR
/SFR = Salite Forza Resistenza. Italian for climbing strength resistance, or at least in my poor Italian that’s how I translate. SFRs are a bread and butter workout that we use with our athletes year round, in different variations and timing of prescription. I don’t believe for a moment that we’re novel in incorporating SFRs, coaches have been prescribing them at least since the 1980s, and people have been riding up steep hills at low cadence for long before that! Other names for SFR efforts that we see are muscle tension, slow frequency repetitions, big gear repeats, et cetera. What I love about SFRs though is that you can put a lot of twists on them to add a bit of specificity to the period you’re in. And regardless of the period you’re in, this is a workout that I feel adds benefit year round in a lot of ways.
For us, SFR means doing efforts @ 50-60 rpm, usually in mid to upper zone 3 power (85-90% of FTP for that school of thought). Every now and then we will have athletes do SFR in zone 4 power, but not regularly. At it’s core, SFRs are about torque / force production. Power = torque x cadence. If an athlete is doing 400 watts @ 90 rpm, they are producing a given torque. Well, riding around all winter doing efforts @ 400 watts is usually more taxing aerobically than they type of work we’re aiming for in that period. But, we still want to train some of the pathways that allow athletes to produce that 400 watts. If we lower the cadence, say from 90 rpm to 50 rpm, of a normal tempo effort an athlete would be doing the torque goes up. Takeaway being one of the big points of SFR is we train the torque demand for higher power efforts, without the aerobic strain. So we are building some of the pathways to top end power, without the same damage / fatigue. Ability to produce torque translates across a large spectrum of demands on the bike. Additionally, by training high torque, we’re training the ability to resist fatigue due to high torque - paramount.
Physiologically there is also a bit more going on, especially when it comes to muscle fiber recruitment. 300 watts done at 90 rpm vs 50 rpm are going to result in different muscle fiber recruitments. To me, I always think of training as “building up a tool box”. So it’s not that the fibers we are recruiting at 50 rpm are more important than the 90 rpm fibers, but we want to be comfortable recruiting all of them. The more muscle showing up to work the better someone’s going to ride in most scenarios.
On a more anecdotal note, there are some things about SFRs that I also believe to be super valuable year round. Pushing the big gear just seems to help set someone up solid and square on the bike - sort of the idea that slowing things down allows for more focus on balance and equality side to side. These efforts are great at building glute recruitment. These efforts are also great for working to keep a calm upper body and controlled breathing. All of this is critical, but it doesn’t necessarily show up as bullet points in the physiological aspects.
OK, quite a bit of why SFRs, but now a little how:
6x4 min SFR (50-60 rpm, high Z3 power) / 3 min recovery - this is a bread and butter session, that we’ll aim to do 1 x per week in the winter/base period and once every 2-3 weeks as maintenance through the race season
SFR “transitions” - this is a twist that is great for switching between cadences and working on lifting to threshold power while already under load. We’ll mix these efforts in a progression of a few variations:
6 x 5 min, of 4 min SFR < 1 min @ threshold, 95+ rpm
3-4 x 8 min alternating 3 min SFR / 1 min @ threshold, 95+ rpm continuously
2-3 x 15 min alternating 4 min SFR / 1 min @ threshold, 95+ rpm continuously
SFR<Punch - another twist, that I really like to use when building to the race season. These require a big sprint from high torque, but not in the isolation of just a sprint without an aerobic load on the front end. I feel it’s a great translation from base fitness towards race specifics. We will usually aim to put this session in 2-3 x in the 4-5 weeks leading up to the start of the race season:
4-8 x 4 min of SFR, but the last 15 sec big sprint out of the saddle from the gear you’re in
Now that you’re sold on SFRs, the next step is to go do them and let us know how it goes. Oh yea, one last caveat emptor. This isn’t one of those workouts that is your big workout and you do it 1-2x per year and you feel like a hero for getting through it. Quite the opposite, we tell athletes all the time that this is a “going through the motions” workout. That can downplay the importance of it, but the reality is that shows how important it is. It’s such a valuable workout we’re doing it all the time, and because we’re doing it all the time it’s about just punching in and punching out. It’s no one workout, but the sum of the workouts that moves the needle. Thanks for reading!
