Tried to hold 170 heart rate but couldn't quite get there. Was a bit tired today, form wasn't the best, ended up slouching a bit while trying to get more pressure and increase effort level and struggled to hold stroke rate up. Worked on hip drive for a while at the end after the intervals. Workout: - 10-min Warmup at 70% - 4 sets of 10' at 90% with 3 minutes rest - 10-min Cooldown at 70%