Cadence work mostly increases your heart rate through leg speed and builds speed endurance but not necessarily leg strength. Our next workout will focus on building leg strength. Doing both the cadence work and this on-the-bike strength work together is a great idea, since they will complement each other.
If you are doing long rides outside, I would suggest adding some hills. When you ride the hills, instead of trying to go up it fast, put your bike in a big gear and grind it out at about 60 rpm. This will keep your heart rate down and turn the climb into a leg-press workout to build strength in your climbing-specific muscles. You can do this workout off road with a lot of success. If you need to do your long rides indoors still, I would suggest turning up the resistance for 3-8 minutes with 5 minutes in between to mimic a hill interval workout with low cadence. You can do these intervals both seated and standing but make sure you are comfortable seated because you need to maintain traction on your mountainbike.
On days where you don’t have time to ride for a long period of time, but have been doing gym workouts lifting weights, this time of year might be a good time to turn these workouts into a circuit. I do this workout at home with a ball, wobble board, weights and Powercranks. Powercranks on the trainer are a challenge. They are cranks which are on an individual clutch system which basically means you are single-legged pedaling all the time. You need a fairly high resistance to keep on top of the cranks, so it becomes a strength workout and you also get the benefit of the technique improvements associated with single leg pedaling. Double bonus! If you do not have Powercranks, or you don’t have space at home to do this kind of workout, do it in the gym with a spinning bike or on your trainer doing some single leg intervals instead of just pedaling.