16 X 100 meters at about 80-85% of max, yes this is a tempo run for sprinters. I ran these on a soccer field as diagonals. Diagonal across a soccer field measures 114 meters but I didn't nit pick on the meters. I just ran. I'm a long time fan of diagonals partly because of the soft surface and also because you don't nit pick or geek out on data, you just run by feel across, then walk the "end zone".
Today I added various exercises to the recovery like walking lunges which I'm doing mainly to rehab my upper hamstring. Eccentric exercises to help with tendinopathy isn't completely understood but one theory is that it smooths the muscle that is attached to the tendon thereby reducing chronic stress on the tendon. This is another reason I massage and scrape my hamstrings every day and place a lacrosse ball under my upper hamstring when I drive. Another is that collagen (what tendons are made of) production is most stimulated by eccentric loads and can help to repair the tendon. Either way it seems to help me mitigate the issue. I also did push-ups, reverse crunches and ankling. I'm still amazed at out how ankling drills can exhaust my lower legs. I do a variation that is less dynamic and more of a heel to toe walking action that focuses more on the tibialis muscle to help build strength and endurance in dorsiflexion. Dorsiflexion of the ankle throughout the leg cycle is something I've never really considered or developed so I feel I have a weakness in that aspect. Plantaar flexion which is not necessarily incorrect and doesn't factor in as much in slower running, does contribute to hamstring stress and is also a wasted movement in sprinting. I've been working on developing muscle memory to keep my ankles flexed while running, which after 34 years of doing it differently is a bit of a struggle.
The suggested rest intervals for tempo vary according to who you talk to ranging from 30" up to 2:00. Today I kept it under a minute with a full recovery after #8. My legs felt healthier than yesterday but definitely fatigued. This session isn't technically a quality run and can be done 2-3 times a week. I personally don't think this should be done that frequently during a race prep phase as it can be a fairly tough session depending on your fatigue and will inhibit recovery needed to ensure quality days are just that. My own outlook with this whole 400 meter race thing has evolved into a 2-3 year plan using this year simply to build and gain experience so I'm not too concerned with trying to peak my potential in my upcoming races. This session though is best done in a general build phases 8+ weeks out from an 'A' race. This is also a complimentary session on a weight training day with the weights after the run. Not exhausting but still stimulating.