The 90-minute free-form session involves going out and riding hard. Sweet Spot training is a great way to increase your lactate threshold, so if you want to improve Time trial performance or hang with the fast group ride this is the workout for you. It’s important to keep a steady effort throughout the interval with no drop or peak in pace. Start at 95 percent of your threshold power. As you fatigue, let your wattage fall slightly but continue to push. You should accept that your wattage will rise and fall as the fatigue sets in, but at about 90 percent power, you will be riding in the sweet spot.