What is sustainable training? Training has to be sustainable in order for us to see results, stay healthy and prevent injury.
For recovery, this actually means recovering from hard workouts or races. Recovery isn't getting a sports massage, foam rolling or wearing compression gear. Recovery is getting sufficient sleep, refuelling enough (and healthily) along with keeping on top of stress and your mental health.
A sustainable approach also isn't deciding to race on the back of no training or cram in multiple races at once. I've seen many runners simply fall back to square one after trying to claw back some fitness or sense of normality from this approach. Runners need to be realistic about the goals they set based off their current fitness.
Invest in sustainable training that priorities recovery as the main element to securing fitness. This is the most practical and efficient way to ensure performance gains
This generally manifests itself in the below list:
-Train all year round, with allocated periods of rest/easy or steady running. Or reduced mileage. This can be an ad-hoc thing to cater for any busy periods at work, stress or simply because you need a mental break.
--Do 2 x speed sessions a week which are ran to feel and intensity/volume is again changed to cater training load, stress, tiredness, or training needs. (So longer threshold/ Tempo stuff for half marathon races etc.)
--keep steady running actually easy and steady. I've seen an uncomfortable amount of people regularly run their easy stuff within a minute of their 5k pace, and this does nothing but wear you down over the long run. Slow down, running is a lot more enjoyable that way, and it means you can retain quality for the speed sessions, increase running mileage without tiring yourself out, and not get injured. Sounds like a pretty good deal to me.
-- In all running you do, listen to how your body is feeling and adjust pace and distance accordingly. Best thing I suggest here is to remove pace/HR readings off your watch entirely.
-- Do races that are right for you and you only. Way too many people get sucked into the noise of races they most likely won't enjoy or is beneficial for them. Find your niche, ignore what anyone else says. Also, running isn't all about the marathon. There's races out there that don't mentally and physically destroy you, and don't come with the noise or stress either. Middle distance stuff is honourable and anyone who suggests a 5k is 'only a 5k' then they haven't raced one before (or properly). 3ks and 5ks aren't just fun runs. From my training with Peterborough I've seen so much energy, passion and enthusiasm put into these distances on the track, it really is inspiring. So do races that make you actually want to do them. Do races that inspire you and motivate you. Not because you have to do them as some 'rite of passage' or prove things to others.
--And finally as per above, recovery is the most important out of anything so sleep loads, refuel very well, and keep yourself healthy , mentally and physically. There's more important things to life than running.