On various surfaces. Practice race starts. Get clipped in and go for 6 x 30-60 sec all out. 5 min recoveries between efforts.
Walk 5 min, Jog 2 min easy HR should be Z-2 or less, Walk 5 min.
On cross bike practice skills: mount/dismount, barriers, run-ups, trails...etc. Keep HR zone 3 or lower. Skills not effort today.
BT: Warmup well then do 3 x 10 min at the top end of your Z-3 and bottom end of your Z-4 HR (5-minute recoveries). Add in 5 x 1 min fast pedaling efforts in a very light gear at 120 rpm (1 min rest) Smooth pedaling. 80-90 rpm.
Walk 5 min, Jog 4 min easy HR should be Z-2 or less, Walk 5 min.
Very easy recovery spin on a flat course. Best on road bike/road wheels. Small chain ring only.
BT: Hilly course with long climbs. Stay in the heart rate 2-4 zones on hills. No anaerobic. Do not force the effort on hills. Hold back some on climbs. Mostly seated on climbs.