Workouts / Interval
Interval
Hard Starts 4x4
4×4:00 hard-start VO2 intervals (30s @ 140% then 3:30 @ 105%) with equal rest.
Duration57:00
TSS52
IF0.74
Blocks5
Time57:00
TSS52
IF0.74
Profile
Targets in % FTP
100%50%0%
0:0028:3057:00
Z1 46% · 26 minZ2 26% · 15 minZ4 25% · 14 minZ6 4% · 2 min
Intervals
5 blocksZ2
Warm-upBuild cadence
15:0060%Repeat 4×
Z6
IntervalHard start @ 140%
0:30140%Z4
IntervalSettle at 105%
3:30105%Z1
RecoveryEqual rest
4:0050%Z1
Cool-downEasy finish
10:0050%What it trains
VO2-focused intervals raise aerobic ceiling and repeatability for attacks, climbs, and hard surges.