Cycling Fitness / Training Advice

That kind of session won't make you slower at this time of year the only thing that will make you slower is not riding your bike. Its a strength endurance session but those won't make you faster for cross or 10 mile tts as they're intense events so you need to replicate that type of intensity or harder in smaller chunks in your training in the 6-8 weeks building up to the season. The low cadence strength/torque endurance sessions are good this time of year as they don't take much out of you if your building volume. A good version of that type of session for you would be to do that but on the recoveries do those under geared at high cadence >110 rpm that makes it more specific for you if your riding sscx as you'll be grinding and spinning during that. I've got plenty of tasty sessions for cx and 10 mile tts when the time comes for those if your interested?