I do a 20 min stairmaster hill program on level 15, really makes me sweat. I often don't do the warm down after the last big hill, so it's really only 17 min.
I've found a way to more effectively use the glute hip machine. I call them 'super sets.' I'm using 350lb on the glute machine, 35 lbs more than I was using in '15 (in this video)
7 sets with 350 lbs each leg then change sides - sets are:
50, 5x20, 40 or to fail
For hip flexors:
5 sets with 220 lbs each leg then change sides - sets are:
20, 3x12, 15 or to fail
So, why can I push so much more with glutes than hip flexors? A couple reasons. Glute is a bigger more powerful muscle. Glute machine I'm pushing down - using both some of my body weight and helped by gravity. Hip flexor I'm pushing up, against gravity. I don't think glutes and hip flexors need to be equal strength. Glutes and upper hams propel the body upward and forward, hip flexors simply recycle the leg back to prepare the next stride. Anyway, I'm really as strong on these exercises as I've ever been but of course, no telling how that will translate to speed. These exercises are great in that they spare the feet and knees and I can do them explosively, but I also do single leg squats, adductor, abductor, and a variety of upper body and core. I hope to continue this regime so long as it doesn't hurt my hips, so far hips are fine. I really think I can make some gains if I start eating better and begin creatine and more protein.
I may well wait til at least Sunday or Monday before I hit the track again. Really want to start running fast but that's weeks away.